Carranza 12e - Furcation Involvement And Treatment 2o5n1n
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CHAPTER 62 Furcation: Involvement and Treatment Thomas Sims and Henry H. Takei CHAPTER OUTLINE Etiologic Factors Diagnosis and Classification of Furcation Defects Local Anatomic Factors
Anatomy of The Bony Lesions Indices of Furcation Involvement Treatment
Nonsurgical Therapy Surgical Therapy Prognosis
For online-only content on root resection, hemisection, and root resection/hemisection procedure in the surgical therapy section, please visit the companion website at www.expertconsult.com. Some figures may be out of numeric order in this printed chapter. Editors Note: An animation (slide show) has been added as a supplement to the chapter by the Editors. This was produced by My Dental Hub as a patient education tool and covers the basic elements in a conceptual manner. It is not intended to be a procedural guide for dental professionals.
The progress of inflammatory periodontal disease, if unabated, ultimately results in attachment loss sufficient enough to affect the bifurcation or trifurcation of multirooted teeth. The furcation is an area of complex anatomic morphology5,6,11 that may be difficult or impossible to debride by routine periodontal instrumentation.29,36 Routine home care methods may not keep the furcation area free of plaque17,23 (see Video 62-1: Bone Loss with Furcation). The presence of furcation involvement is one clinical finding that can lead to a diagnosis of advanced periodontitis and potentially to a less-favorable prognosis for the affected tooth or teeth. Furcation involvement therefore presents both diagnostic and therapeutic dilemmas.
Etiologic Factors The primary etiologic factor in the development of furcation defects is bacterial plaque and the inflammatory consequences that result from its long-term presence. The extent of attachment loss required to produce a furcation defect is variable and related to local anatomic factors (e.g., root trunk length, root morphology)12,27 and local developmental anomalies (e.g., cervical enamel projections).22,27 Local factors may affect the rate of plaque deposition or complicate the performance of oral hygiene procedures, thereby contributing to the development of periodontitis and attachment loss. Studies indicate that prevalence and severity of furcation involvement increase with age.21,22,36 Dental caries and pulpal death may also affect a tooth with furcation involvement or even the area of the furcation. All of these factors should be considered during the diagnosis, treatment planning, and therapy of the patient with furcation defects.
Diagnosis and Classification of Furcation Defects A thorough clinical examination is the key to diagnosis and treatment planning. Careful probing is required to determine the presence and extent of furcation involvement, the position of the attachment relative to the furca, and the extent and configuration
of the furcation defect.38 The Nabors probe may be helpful to enter and measure difficult to access furcal areas (Figure 62-1). Transgingival sounding may further define the anatomy of the furcation defect.29 The goal of this examination is to identify and classify the extent of furcation involvement and to identify factors that may have contributed to the development of the furcation defect or that could affect treatment outcome. These factors include (a) the morphology of the affected tooth, (b) the position of the tooth relative to adjacent teeth, (c) the local anatomy of the alveolar bone, (d) the configuration of any bony defects, and (e) the presence and extent of other dental diseases (e.g., caries, pulpal necrosis). The dimension of the furcation entrance is variable but usually quite small; 81% of furcations have an orifice of l mm or less, and 58% are 0.75 mm or less.5,6 The clinician should consider these dimensions, and the local anatomy of the furcation area,11-13 when selecting instruments for probing. A probe of small cross-sectional dimension is required if the clinician is to detect early furcation involvement.
Local Anatomic Factors Clinical examination of the patient should allow the therapist to identify not only furcation defects but also many of the local anatomic factors that may affect the result of therapy (prognosis). Well-made dental radiographs, although not allowing a definitive classification of furcation involvement, provide additional information vital for treatment planning (Figure 62-2). Important local factors include anatomic features of the affected teeth, as described next.
Root Trunk Length A key factor in both the development and the treatment of furcation involvement is the root trunk length. The distance from the cementoenamel junction to the entrance of the furcation can vary extensively. Teeth may have very short root trunks, moderate root trunk length, or roots that may be fused to a point near the apex (Figure
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62-3). The combination of root trunk length with the number and configuration of the roots affects the ease and success of therapy. The shorter the root trunk, the less attachment needs to be lost before the furcation is involved. Once the furcation is exposed, teeth with short root trunks may be more accessible to maintenance procedures, and the short root trunks may facilitate some surgical procedures. Alternatively, teeth with unusually long root trunks or fused roots may not be appropriate candidates for treatment once the furcation has been affected.
Root Length Root length is directly related to the quantity of attachment ing the tooth. Teeth with long root trunks and short roots may have lost a majority of their by the time that the furcation becomes affected.13,20 Teeth with long roots and short-to-moderate root trunk length are more readily treated because sufficient attachment remains to meet functional demands.
Root Form The mesial root of most mandibular first and second molars and the mesiofacial root of the maxillary first molar are typically curved to the distal side in the apical third. In addition, the distal aspect of this root is usually heavily fluted. The curvature and fluting may increase the potential for root perforation during endodontic therapy or complicate post placement during restoration.1,25 These anatomic features may also result in an increased incidence of vertical root fracture. The size of the mesial radicular pulp may result in removal of most of this portion of the tooth during preparation.
Interradicular Dimension The degree of separation of the roots is also an important factor in treatment planning. Closely approximated or fused roots can preclude adequate instrumentation during scaling, root planing, and surgery. Teeth with widely separated roots present more treatment options and are more readily treated.
Anatomy of Furcation The anatomy of the furcation is complex. The presence of bifurcational ridges, a concavity in the dome,11 and possible accessory canals16 complicates not only scaling, root planing, and surgical therapy,28 but also periodontal maintenance. Odontoplasty to reduce or eliminate these ridges may be required during surgical therapy for an optimal result.
Cervical Enamel Projections Cervical enamel projections (CEPs) are reported to occur on 8.6% to 28.6% of molars.26,27,35 The prevalence is highest for mandibular and maxillary second molars. The extent of CEPs was classified by Masters and Hoskins27 in 1964 (Box 62-1). Figure 62-4 provides an example of a grade III CEP. These projections can affect plaque removal, can complicate scaling and root planing, and may be a local factor in the development of gingivitis and periodontitis. CEPs should be removed to facilitate maintenance.
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Anatomy of the Bony Lesions Pattern of Attachment Loss B Figure 62-1 A, The Nabors probe is designed to probe into the
furcation. B, The probe placed into a Class II furcation of a dried skull.
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The form of the bony lesions associated with the furcation can vary significantly. Horizontal bone loss can expose the furcation as thin facial/lingual plates of bone that may be totally lost during resorption. Alternatively, areas with thickened bony ledges may persist and predispose to the development of furcations with deep vertical components. The pattern of bone loss on other surfaces of the
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Figure 62-2 Different degrees of furcation involvement in radiographs. A, Grade I furcation on the mandibular first molar and a grade III furcation on the mandibular second molar. The root approximation on the second molar may be sufficient to impede accurate probing of this defect. B, Multiple furcation defects on a maxillary first molar. Grade I buccal furcation involvement and grade II mesiopalatal and distopalatal furcations are present. Deep developmental grooves on the maxillary second molar simulate furcation involvement in this molar with fused roots. C, Grades III and IV furcations on mandibular molars.
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BOX 62-1 Classification of Cervical Enamel Projections Grade I: The enamel projection extends from the cementoenamel junction of the tooth toward the furcation entrance. Grade II: The enamel projection approaches the entrance to the furcation. It does not enter the furcation, and therefore no horizontal component is present. Grade III: The enamel projection extends horizontally into the furcation. From Masters DH, Hoskins SW: J Periodontol 35:49, 1964.
Figure 62-5 Advanced bone loss, furcation involvement, and
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root approximation. Note the buccal furcation, which communicates with the distal furcation of a maxillary first molar that also displays advanced attachment loss on the distal root and approximation with the mesial root of the maxillary second molar. The patient with such teeth may benefit from root resection of the distobuccal root of the first molar or extraction of the molar.
Figure 62-3 Different anatomic features that may be important
in prognosis and treatment of furcation involvement. A, Widely separated roots. B, Roots are separated but close. C, Fused roots separated only in their apical portion. D, Presence of enamel projection that may be conducive to early furcation involvement.
development of a number of indices to record furcation involvement. These indices are based on the horizontal measurement of attachment loss in the furcation,14,17 on a combination of horizontal and vertical measurements,37 or a combination of these findings with the localized configuration of the bony deformity.10 Glickman14 classified furcation involvement into four grades (Figure 62-6).
Grade I A grade I furcation involvement is the incipient or early stage of furcation involvement (see Figure 62-6, A). The pocket is suprabony and primarily affects the soft tissues. Early bone loss may have occurred with an increase in probing depth, but radiographic changes are not usually found.
Grade II Figure 62-4 Furcation involvement by grade III cervical enamel
projections.
affected tooth and adjacent teeth must also be considered during treatment planning. The treatment response in deep, multiwalled bony defects is different from that in areas of horizontal bone loss. Complex multiwalled defects with deep, interradicular vertical components may be candidates for regenerative therapies. Alternatively, molars with advanced attachment loss on only one root may be treated by resective procedures.
Other Dental Findings The dental and periodontal condition of the adjacent teeth must be considered during treatment planning for furcation involvement. The combination of furcation involvement and root approximation with an adjacent tooth represents the same problem that exists in furcations without adequate root separation. Such a finding may dictate the removal of the most severely affected tooth or the removal of a root or roots (Figure 62-5). The presence of an adequate band of gingiva and a moderate to deep vestibule will facilitate the performance of a surgical procedure, if indicated.
Indices of Furcation Involvement The extent and configuration of the furcation defect are factors in both diagnosis and treatment planning. This has led to the
A grade II furcation can affect one or more of the furcations of the same tooth. The furcation lesion is essentially a cul-de-sac (see Figure 62-6, B) with a definite horizontal component. If multiple defects are present, they do not communicate with each other because a portion of the alveolar bone remains attached to the tooth. The extent of the horizontal probing of the furcation determines whether the defect is early or advanced. Vertical bone loss may be present and represents a therapeutic complication. Radiographs may or may not depict the furcation involvement, particularly with maxillary molars because of the radiographic overlap of the roots. In some views, however, the presence of furcation “arrows” indicates possible furcation involvement (see Chapter 31).
Grade III In grade III furcations, the bone is not attached to the dome of the furcation. In early grade III involvement, the opening may be filled with soft tissue and may not be visible. The clinician may not even be able to a periodontal probe completely through the furcation because of interference with the bifurcational ridges or facial/ lingual bony margins. However, if the clinician adds the buccal and lingual probing dimensions and obtains a cumulative probing measurement that is equal to or greater than the buccal/lingual dimension of the tooth at the furcation orifice, the clinician must conclude that a grade III furcation exists (see Figure 62-6, C). Properly exposed and angled radiographs of early Class III furcations
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Figure 62-6 Glickman’s classification of furcation involvement. A, Grade I furcation involvement. Although a space is visible at the entrance to the furcation, no horizontal component of the furcation is evident on probing. B, Grade II furcation in a dried skull. Note both the horizontal and the vertical component of this cul-de-sac. C, Grade III furcations on maxillary molars. Probing confirms that the buccal furcation connects with the distal furcation of both these molars, yet the furcation is filled with soft tissue. D, Grade IV furcation. The soft tissues have receded sufficiently to allow direct vision into the furcation of this maxillary molar.
display the defect as a radiolucent area in the crotch of the tooth (see Chapter 31).
Grade IV In grade IV furcations, the interdental bone is destroyed, and the soft tissues have receded apically so that the furcation opening is clinically visible. A tunnel therefore exists between the roots of such an affected tooth. Thus the periodontal probe es readily from one aspect of the tooth to another (see Figure 62-6, D).
Other Classification Indices Hamp et al17 modified a three-stage classification system by attaching a millimeter measurement to separate the extent of horizontal involvement. Easley and Drennan10 and Tarnow and Fletcher37 have described classification systems that consider both horizontal and vertical attachment loss in classifying the extent of furcation involvement. The Tarnow and Fletcher article utilizes a subclassification that measures the probeable vertical depth from the roof of the furca apically. The subclasses being proposed are: A, B, and C. “A” indicates a probeable vertical depth of 1 to 3 mm, “B” indicates 4 to 6 mm, and “C” indicates 7 or more mm of probeable depth from the roof of the furca apically. Furcations would thus be classified as IA, IB, and IC; IIA, IIB, and IIC; and IIIA, IIIB, and IIIC. Consideration of defect configuration and the vertical component of the defect provides additional information that is useful in planning therapy.
Treatment The objectives of furcation therapy are to (a) facilitate maintenance, (b) prevent further attachment loss, and (c) obliterate the furcation defects as a periodontal maintenance problem. The
selection of therapeutic mode varies with the class of furcation involvement, the extent and configuration of bone loss, and other anatomic factors.
Therapeutic Classes of Furcation Defects Class I: Early Defects. Incipient or early furcation defects
(Class I) are amenable to conservative periodontal therapy.15 Because the pocket is suprabony and has not entered the furcation, oral hygiene, scaling, and root planing are effective.16 Any thick overhanging margins of restorations, facial grooves, or CEPs should be eliminated by odontoplasty, recontouring, or replacement. The resolution of inflammation and subsequent repair of the periodontal ligament and bone are usually sufficient to restore periodontal health.
Class II. Once a horizontal component to the furcation has devel-
oped (Class II), therapy becomes more complicated. Shallow horizontal involvement without significant vertical bone loss usually responds favorably to localized flap procedures with odontoplasty, osteoplasty, and ostectomy. Isolated deep Class II furcations may respond to flap procedures with osteoplasty and odontoplasty (Figure 62-7). This reduces the dome of the furcation and alters gingival contours to facilitate the patient’s plaque removal.
Classes II to IV: Advanced Defects. The development of
a significant horizontal component to one or more furcations of a multirooted tooth (late Class II, Class III, or Class IV13) or the development of a deep vertical component to the furca poses additional problems. Nonsurgical treatment is usually ineffective because the ability to instrument the tooth surfaces adequately is compromised.31,40 Periodontal surgery, endodontic therapy, and restoration of the tooth may be required to retain the tooth.
CHAPTER 62 Furcation: Involvement and Treatment
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Figure 62-7 Treatment of a grade II furcation by osteoplasty and odontoplasty. A, This mandibular first molar has been treated endodontically and an area of caries in the furcation repaired. A Class II furcation is present. B, Results of flap debridement, osteoplasty, and severe odontoplasty 5 years postoperatively. Note the adaptation of the gingiva into the furcation area. (Courtesy Dr. Ronald Rott, Sacramento, CA.)
Nonsurgical Therapy Oral Hygiene Procedures Furcal management is difficult at best. Therapeutic modalities for the treatment and maintenance of furcations have long been a dilemma amongst periodontists and restorative dentists. Nonsurgical therapy is a very effective way of producing a satisfactory stable result. Ideal results with furcations are impossible to obtain. Once furcation breakdown has begun, there is always a somewhat compromised result clinically. Both surgical and nonsurgical therapies have been shown to work effectively over time. Nonsurgical therapy, a combination of oral hygiene instruction and scaling and root planing, has provided excellent results in some patients. The earlier the furcation is detected and treated the more likely a good long-term result can be obtained. Nonetheless, even advanced furcation lesions can have successful long-term treatment.34 Several oral hygiene procedures have been used over time. All include access to the furcation. Obtaining access to the furcation requires a combination of the awareness of the furcation by the patient and an oral hygiene tool that facilitates that access. Many tools, including rubber tips; periodontal aids; toothbrushes, both specific and general; and other aids have been used over time for access to the patient (Figure 62-8).
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Scaling and Root Planing Nonsurgical maintenance by the clinician has also improved over time as instrumentation has improved. In recent decades, instruments beyond simple curettes have been used to instrument the furcation. The frustration of instrumentation of the furcation was illustrated beautifully by Bower in 1979 in his articles5,6 showing that only 58% of furcations could be entered by typically using curettes (see Chapter 33). Subsequently, other instrumentation has evolved, including DeMarco curettes, diamond files, Quetin furcation curettes, and mini Five Gracey Curettes. See Chapter 46 for a detailed discussion on this subject. Svärdström and Wennström34 illustrated that in the long term, furcations could be maintained using nonaggressive techniques over a 10-year period in patients who were participants in consistent maintenance. Other studies also illustrate that maintenance therapy is useful for patients to facilitate furcation cleanliness. Chemotherapy has proven disappointing. Ribeiro et al32 found that nonsurgical therapy can effectively treat Class II furcation involvements, but using povidone-iodine did not provide additional benefits to subgingival instrumentation.
B Figure 62-8 A, The utilization of a Perio-Aid into the furcation for
plaque removal. B, Proxy brush is used for plaque removal into the furcation lesion. (Courtesy Karen DeYoung, RDH, and Janet Shigekawa, RDH.)
The area most critical in furcation management is maintaining a relatively plaque-free status to the furcation. Attaining access is a problem in this regard, but with the previously mentioned instruments and an effective nonsurgical approach, much can be accomplished. The most critical component of multirooted tooth maintenance is always the successful reduction or elimination of plaque retention areas from the furcation area; meticulous oral hygiene by the patient and an effective nonsurgical therapy can play a major role in attaining this goal.21,33
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Surgical Therapy Osseous Resection Osseous surgical therapy can be divided into resective and regenerative therapy. This also applies to the furcation areas when surgical therapy is contemplated. For many years, osteoplasty and ostectomy have been used to make the furcation areas cleansable. In the advanced cases, techniques were used to open the furcation into a Class IV from a severe Class II or III case. This would allow easier hygiene into the furcation area for the patient. These techniques have limited usefulness today, but in the compromised individual in whom teeth cannot be extracted or in whom conservative therapy has failed, these surgical techniques have been used. The immediate goal with these surgical approaches is to create access for the patient to maintain good hygiene.
Regeneration In furcal lesions, bone regeneration is often thought to be relatively futile. The periodontal literature has well-documented therapeutic efforts designed to induce new attachment and reconstruction on molars with furcation defects. Many surgical procedures using a variety of grafting materials have been tested on teeth with different classes of furcation involvement. Some investigators have reported clinical success,24 whereas others have suggested that the use of these materials in Class II, III, or IV furcations offers little advantage compared with surgical controls.3,9,30 Furcation defects with deep two-walled or three-walled components may be suitable for reconstruction procedures. These vertical bony deformities respond favorably to a variety of surgical procedures, including debridement with or without membranes and bone grafts. Chapter 61 addresses therapies designed to induce new attachment or reattachment. Tsao et al39 have shown that the furcation defect is a graftable lesion. They found that lesions that were grafted had greater vertical fill than areas treated with open flap debridement alone. Bowers et al7 have shown furcation bone grafting using various membranes can improve the clinical status of these lesions. Nonetheless, bone grafting remains an elusive goal with variable results in furcation lesions. Another area of interest has been barrier membrane technology. Analysis of published studies demonstrated a great variability in the clinical outcomes in mandibular grade II furcations treated with different types of nonbioabsorbable and bioabsorbable barrier membranes. Although many barrier membrane studies show a slight clinical improvement after treatment in both maxillary and mandibular furcations, the results are generally inconsistent.
Extraction The extraction of teeth with through-and-through furcation defects (Classes III and IV) and advanced attachment loss may be the most appropriate therapy for some patients. This is particularly true for individuals who cannot or will not perform adequate plaque control, who have a high level of caries activity, who will not commit to a suitable maintenance program, or who have socioeconomic factors that may preclude more complex therapies. Some patients are reluctant to accept periodontal surgery or even allow the removal of a tooth with advanced furcation involvement, even though the long-term prognosis is poor. The patient may elect to forego therapy, opt to treat the area with scaling and root planing or site-specific antibacterial therapies, and delay extraction until the tooth becomes symptomatic. Although additional attachment loss may occur, such teeth may survive a significant number of years.21,33
Dental Implants The advent of osseointegrated dental implants as an alternative abutment source has had a major impact on the retention of teeth with advanced furcation problems. The high level of predictability of osseointegration may motivate the therapist and patient to consider removal of teeth with a guarded or poor prognosis and to seek an implant-ed prosthetic treatment plan. Therefore careful evaluation of the long-term periodontal, endodontic, and restorative prognosis must be considered before invasive surgical therapy is undertaken to save a tooth with an advanced furcated lesion (Figure 62-15).
Prognosis For many years the presence of significant furcation involvement meant a hopeless long-term prognosis for the tooth. Clinical research, however, has indicated that furcation problems are not as severe a complication as originally suspected if one can prevent the development of caries in the furcation. Relatively simple periodontal therapy is sufficient to maintain these teeth in function for long periods.21,33 Other investigators have defined the reasons for clinical failure of root-resected or hemisected teeth.2,25 Their data indicate that recurrent periodontal disease is not a major cause of the failure of these teeth. Investigations of root-resected or hemisected teeth have shown that such teeth can function successfully for long periods.2,8,25 The keys to long-term success appear to be (a) thorough diagnosis, (b) selection of patients with good oral hygiene, (c) excellence in nonsurgical therapy, and (d) careful surgical and restorative management.
CHAPTER 62 Furcation: Involvement and Treatment
Root Resection Root resection may be indicated in multirooted teeth with grades II to IV furcation involvements. Root resection may be performed on vital teeth19 or endodontically treated teeth. It is preferable, however, to have endodontic therapy completed before resection of a root(s).18 If this is not possible, the pulp should be removed, the patency of the canals determined, and the pulp chamber medicated before resection. It is distressing for both patient and clinician to perform a vital root resection and subsequently have an unfavorable event occur, such as perforation, fracture of the root, or an inability to instrument the canal. The indications and contraindications for root resection were well summarized by Bassaraba.1 In general, teeth planned for root resection include the following: 1. Teeth that are critically important to the overall dental treatment plan.4 Examples are teeth serving as abutments for fixed or removable restorations for which loss of the tooth would result in loss of the prosthesis and entail major prosthetic retreatment. 2. Teeth that have sufficient attachment remaining for function. Molars with advanced bone loss in the interproximal and interradicular zones, unless the lesions have three bony walls, are not candidates for root amputation. 3. Teeth for which a more predictable or cost-effective method of therapy is not available. Examples are teeth with furcation defects that have been treated successfully with endodontics but now present with a vertical root fracture, advanced bone loss, or caries on the root. 4. Teeth in patients with good oral hygiene and low activity for caries are suitable for root resection. Patients unable or unwilling to perform good oral hygiene and preventive measures are not suitable candidates for root resection or hemisection. Rootresected teeth require endodontic treatment18 and usually cast restorations. These therapies can represent a sizable financial investment by the patient in an effort to save the tooth. Alternative therapies and their impact on the overall treatment plan should always be considered and presented to the patient.
Which Root to Remove. A tooth with an isolated furcation defect in an otherwise intact dental segment may present few diagnostic problems. However, the existence of multiple furcation defects of varying severity combined with generalized advanced periodontitis can be a challenge to treatment planning. Careful diagnosis usually allows the therapist to determine the feasibility of root resection and the identification of which root to remove before surgery (Figure 62-9). Every attempt should be made to determine this prior to surgical exposure. The following is a guide to determining which root should be removed in these cases: 1. Remove the root(s) that will eliminate the furcation and allow the production of a maintainable architecture on the remaining roots. 2. Remove the root with the greatest amount of bone and attachment loss. Sufficient periodontal attachment must remain after surgery for the tooth to withstand the functional demands placed on it such as bridge abutments and in bruxers. Teeth with uniform advanced horizontal bone loss are not suitable for root resection. 3. Remove the root that best contributes to the elimination of periodontal problems on adjacent teeth. For example, a maxillary first molar with a Class III buccal-to-distal furcation is
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adjacent to a maxillary second molar with a two-walled intrabony defect between the molars and an early Class II furcation on the mesial furcation of the second molar. There may or may not be local anatomic factors affecting the teeth. The removal of the distobuccal root of the first molar allows the elimination of the furcation and management of the two-wall intrabony lesion and also facilitates access for instrumentation and maintenance of the second molar. 4. Remove the root with the greatest number of anatomic problems such as severe curvature, developmental grooves, root flutings, or accessory and multiple root canals. 5. Remove the root that least complicates future periodontal maintenance.
Hemisection Hemisection is the splitting of a two-rooted tooth into two separate portions. This process has been called bicuspidization or separation because it changes the molar into two separate roots. Hemisection is most likely to be performed on mandibular molars with buccal and lingual Class II or III furcation involvements. As with root resection, molars with advanced bone loss in the interproximal and interradicular zones are not good candidates for hemisection. After sectioning of the teeth, one or both roots can be retained. This decision is based on the extent and pattern of bony loss, root trunk and root length, ability to eliminate the osseous defect, and endodontic and restorative considerations. The anatomy of the mesial roots of mandibular molars often leads to their extraction and the retention of the distal root to facilitate both endodontic and restorative therapy. The interradicular dimension between the two roots of a tooth to be hemisected is also important. Narrow interradicular zones can complicate the surgical procedure. The retention of both molar roots can complicate the restoration of the tooth, since it may be virtually impossible to finish margins or to provide an adequate embrasure between the two roots for effective oral hygiene and maintenance (Figure 62-10). Therefore, orthodontic separation of the roots is often required to allow restoration with adequate embrasure form (Figure 62-11). The result can be the need for multiple procedures and extensive interdisciplinary therapy. In these patients the availability of other treatment alternatives should be considered such as guided tissue/guided bone regeneration or replacement by osseointegrated dental implants.
Root Resection/Hemisection Procedure The most common root resection involves the distobuccal root of the maxillary first molar,2,26 as diagrammed in Figure 62-12. After appropriate local anesthesia, a full-thickness mucoperiosteal flap is elevated. Root resection or hemisection of teeth with advanced attachment loss usually requires opening both facial and lingual/ palatal flaps (see Chapter 57). Typically, a root cannot be resected without elevating a flap. The flap should provide adequate access for visualization and instrumentation and minimize surgical trauma. After debridement, resection of the root begins with the exposure of the furcation on the root to be removed (see Figure 62-12, A). The removal of a small amount of facial or palatal bone may be required to provide access for elevation and facilitate root removal (see Figure 62-12, B). A cut is then directed from just apical to the point of the tooth, through the tooth, and to the facial and distal orifices of the furcation (see Figure 62-12, C). This cut is made with a high-speed, surgical-length fissure or crosscut fissure carbide bur. The placement of a curved periodontal probe into or through the furcation aids in orienting the angle of the resection. For hemisection, a vertically oriented cut is made
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Figure 62-9 Resection of a root with advanced bone loss. A, Facial osseous contours. There is an early grade II furcation on the facial
aspect of the mandibular first molar and a Class III furcation on the mandibular second molar. B, Resection of the mesial root. The mesial portion of the crown was retained to prevent mesial drift of the distal root during healing. The grade II furcations were treated by osteoplasty. C, Buccal flaps adapted and sutured. D, Lingual flaps adapted and sutured. E, Three-month postoperative view of the buccal aspect of this resection. New restorations were subsequently placed. F, Three-month postoperative view of the lingual aspect of this resection.
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Figure 62-10 A, Grade III furcation lesion. B, Hemisection to divide the tooth into mesial and distal portions. C, Postoperative view of a
hemisected mandibular with new crowns for both roots.
CHAPTER 62 Furcation: Involvement and Treatment
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Figure 62-11 Hemisection and interradicular dimension. A, Buccal preoperative view of a mandibular right second molar with a deep
grade II buccal furcation and root approximation. B, Buccal view of bony lesions with flaps. Note the mesial and distal one-wall bony defects. The lingual furcation was similarly affected. C, The molar has been hemisected and partially prepared for temporary crowns. Observe the minimal dimension between the two roots. D, Buccal view 3 weeks postoperatively. Because the embrasure space is minimal, these roots will be separated with orthodontic therapy to facilitate restoration. (Courtesy Dr. Louis Cuccia, Roseville, CA.)
faciolingually through the buccal and lingual developmental grooves of the tooth, through the pulp chamber, and through the furcation. If the sectioning cut es through a metallic restoration, the metallic portion of the cut should be made before flap elevation. This prevents contamination of the surgical field with metallic particles. If a vital root resection is to be performed, a more horizontal cut through the root is advisable (see Figure 62-12, D). An oblique cut exposes a large surface area of the radicular pulp and/or dental pulp chamber. This can lead to postoperative pain and can complicate endodontic therapy. A horizontal cut, although it may complicate root removal, has fewer postoperative complications. This root stump can be removed by odontoplasty after the completion of endodontic therapy or at the time of tooth preparation. After sectioning, the root is elevated from its socket (see Figure 62-12, E). Care should be taken not to traumatize bone on the remaining roots or to damage an adjacent tooth. Removal of the root provides visibility to the furcation aspects of the remaining roots and simplifies the debridement of the furcation with hand, rotary, or ultrasonic instruments. If necessary, odontoplasty is performed to
remove portions of the developmental ridges and prepare a furcation that is free of any deformity that would enhance plaque retention or adversely affect plaque removal (see Figure 62-12, F). Patients with advanced periodontitis often have root resection performed in conjunction with other surgical procedures. Figure 68-13 provides an example of combining root resection and periodontal osseous surgery. The bony lesions that may be present on adjacent teeth are then treated using resective or regenerative therapies. After resection, the flaps are then approximated to cover any grafted tissues or slightly cover the bony margins around the tooth. Sutures are then placed to maintain the position of the flaps. The area may or may not be covered with a surgical dressing. The removal of a root alters the distribution of occlusal forces on the remaining roots. Therefore, it is wise to evaluate the occlusion of teeth from which roots have been resected and, if necessary, adjust the occlusion. Centric holds should be maintained, but eccentric forces should be eliminated from the area over the root that was removed. Patients with advanced attachment loss may benefit from temporary stabilization of the resected tooth to prevent movement (Figure 62-14).
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Figure 62-12 Diagrams of distobuccal root resection of maxillary first molar. A, Preoperative bony contours with grade II buccal furca-
tion and a crater between the first and second molar. B, Removal of bone from the facial side of the distobuccal root and exposure of the furcation for instrumentation. C, Oblique section that separates the distal root from the mesial and palatal roots of the molar. D, More horizontal section that may be used on a vital root amputation because it exposes less of the pulp of the tooth. E, Areas of application of instruments to elevate the sectioned root. F, Final contours of the resection.
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Figure 62-13 Hemisection combined with osseous surgery to treat furcation defects. A, Buccal preoperative view with provisional
bridge. B, Lingual view with provisional bridge in place. C, Radiograph of bony defects. Note the deep mesial bony defect, largely of one wall, and the radiolucent area in the furcation of the first molar, indicating a grade II defect. D, Buccal view before osseous surgery. In addition to the furcation involvement, a root separation problem exists between the two roots of the first molar. Class II furcations are present on the second molar. E, Buccal view after osseous surgery. Mesial root hemisected and removed. The other defects were treated by osteoplasty and ostectomy. F, Lingual preoperative view. Note the heavy bony ledging at the lingual surface of these first and second molars. G, Lingual postoperative view. The mesial root has been resected, the bony ledging recontoured, and the grade II furcations treated by osteoplasty. H, Buccal view 10 years after treatment. I, Lingual view 10 years after treatment. (Courtesy Dr. Louis Cuccia, Roseville, CA.)
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Figure 62-14 Mesial root resection in the presence of advanced bone loss. A and B, Buccal and lingual preoperative views. Note the
soft-tissue contours that are predictive of the bony defects. C, Radiograph of extent of furcation involvement of the first and second molars. D and E, Buccal preoperative and postoperative views. The mesial root of the second molar was resected and the interproximal craters treated by osteoplasty and minor ostectomy. F and G, Lingual preresection and postresection views. The heavy ledges and horizontal bone loss on the lingual surface were managed by osteoplasty. H and I, Buccal and lingual views 6 weeks postoperatively. A temporary wire splint has been bonded to the molars to prevent tipping of the distal root of the mandibular second molar. (Courtesy Dr. Louis Cucci, Roseville, CA.)
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C Figure 62-15 A, Clinical picture of a Class III furcation involvement. B, Radiographic appearance is far more grave than the clinical appearance. C, After the tooth is removed, a computed tomography (CT) radiograph is taken to plan treatment for implant replacement. D, The implant restored. (Courtesy Dr. Sarvenaz Angha, Los Angeles.)
Suggested Readings DeSanctis M, Murphy KG: The role of resective periodontal surgery in the treatment of furcation defects. J Periodontol 22:154–168, 2000. Newell DH: The diagnosis and treatment of molar furcation invasions. Dent Clin North Am 42(2):301–337, 1998.
References References for this chapter are found on the companion website www.expertconsult.com.
CHAPTER 62 Furcation: Involvement and Treatment
References 1. Bassaraba N: Root amputation and tooth hemisection. Dent Clin North Am 13:121, 1969. 2. Basten CH, Ammons WF, Persson R: Long-term evaluation of root resected molars: a retrospective study. Int J Periodont Restor Dent 16(3):207, 1996. 3. Becker W, Becker BE, Berg L, et al: New attachment after treatment with root isolation procedures: report for treated class III and class II furcations and vertical osseous defects. Int J Periodont Restor Dent 8(3):9, 1988. 4. Black GV: The American system of dentistry, Philadelphia, 1886, Lea Brothers. 5. Bower RC: Furcation morphology relative to periodontal treatment: furcation root surface anatomy. J Periodontol 50:366, 1979. 6. Bower RC: Furcation morphology relative to periodontal treatment: furcation entrance architecture. J Periodontol 50:23, 1979. 7. Bowers GM, Schallhorn RG, McClain PK, et al: Factors influencing the outcome of regenerative therapy in mandibular class II furcations: part I. J Periodontol 74(9):1255–1268, 2003. 8. Carnevale G, DiFebo G, Toyelli MP, et al: A retrospective analysis of the periodontal-prosthodontic treatment of molars with interradicular lesions. Int J Periodont Restor Dent 11:188, 1991. 9. Demolon IA, Person GR, Ammons WF, et al: Effects of antibiotic treatment on clinical conditions with guided tissue regeneration: oneyear results. J Periodontol 65:713, 1994. 10. Easley JR, Drennan GA: Morphological classification of the furca. J Can Dent Assoc 35:104, 1969. 11. Everett F, Jump E, Holder T, et al: The intermediate bifurcational ridge: a study of the morphology of the bifurcation of the lower molar. J Dent Res 37:162, 1958. 12. Gher ME, Vernino AR: Root morphology: clinical significance in pathogenesis and treatment of periodontal disease. J Am Dent Assoc 101:627, 1980. 13. Gher ME, Jr, Dunlap RW: Linear variation of the root surface area of the maxillary first molar. J Periodontol 56:39, 1985. 14. Glickman I: Clinical periodontology, Philadelphia, 1953, Saunders. 15. Goldman HM: Therapy of the incipient bifurcation involvement. J Periodontol 29:112, 1958. 16. Gutmann JL: Prevalence, location and patency of accessory canals in the furcation region of permanent molars. J Periodontol 49:21, 1978. 17. Hamp SE, Nyman S, Lindhe J: Periodontal treatment of multirooted teeth. Results after 5 years. J Clin Periodontol 2:126, 1975. 18. Harrington GW: The perio-endo question: differential diagnosis. Dent Clin North Am 23:673, 1979. 19. Haskell EW, Stanley HR: A review of vital root resection. Int J Periodont Restor Dent 2(6):29, 1982. 20. Hermann DW, Gher ME, Jr, Dumlap RM, et al: The potential attachment area of the maxillary first molar. J Periodontol 54:431, 1983. 21. Hirschfeld L, Wasserman B: A long-term survey of tooth loss in 600 treated periodontal patients. J Periodontol 49:225, 1978.
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22. Hou GL, Tasai CC: Relationship between periodontal furcation involvement and molar cervical enamel projection. J Periodontol 58:715, 1978. 23. Kalkwarf K, Kaldahl W, Patil K, et al: Evaluation of furcation region response to periodontal therapy. J Periodontol 59:794, 1988. 24. Kenney EB, Lekovic V, Elbaz JJ, et al: The use of porous hydroxylapatite implants in periodontal defects. II. Treatment of class II furcation lesions in lower molars. J Periodontol 59:67, 1988. 25. Langer B, Stein SD, Wagenberg B: An evaluation of root resections: a ten-year study. J Periodontol 52:719, 1981. 26. Larato DC: Some anatomical factors related to furcation involvement. J Periodontol 46:608, 1975. 27. Masters DH, Hoskins SW: Projection of cervical enamel into molar furcations. J Periodontol 35:49, 1964. 28. Matia JB, Bissada NF, Maybury JE, et al: Efficiency of scaling of the molar furcation area with and without surgical access. Int J Periodont Restor Dent 6(6):25, 1986. 29. Mealy BL, Beybayer MF, Butzin CA, et al: Use of furcal bone sounding to improve accuracy of furcation diagnosis. J Periodontol 65:649, 1994. 30. Metzler DG, Seamons BC, Mellonig JT, et al: Clinical evaluation of guided tissue regeneration in the treatment of maxillary class II molar furcation. J Periodontol 62:353, 1991. 31. Parashis AO, Anognou-Vareltzides A, Demetrious N: Calculus removal from multirooted teeth with and without surgical access. I. Efficacy on external and furcation surfaces in relation to probing depth. J Clin Periodontol 20:63, 1993. 32. Ribeiro EDP, Bittencourt S, Ambrosano GMB, et al: Povidone-iodine used as an adjunct to non-surgical treatment of furcation involvements. J Periodontol 77(2):211–217, 2006. 33. Ross I, Thompson RH: A long-term study of root retention of maxillary molars with furcation involvement. J Periodontol 49:238, 1978. 34. Svärdström G, Wennström J: Periodontal treatment decisions for molars: an analysis of influencing factors and long-term outcome. J Periodontol 71(4):579–585, 2000. 35. Tal H: Furcal bony defects in dry mandibles. I. Biometric study. J Periodontol 53:360, 1982. 36. Tal H, Lemmer J: Furcal defects in dry mandibles. II. Severity of furcal defects. J Periodontol 53:364, 1982. 37. Tarnow D, Fletcher P: Classification of the vertical component of furcation involvement. J Periodontol 55:283, 1984. 38. Tibbetts LF: Use of diagnostic probes for detection of periodontal disease. J Am Dent Assoc 78:549, 1969. 39. Tsao Y, Neiva R, Al-Shammari K, et al: Factors influencing treatment outcomes in mandibular class II furcation defects. J Periodontol 77(4):641–646, 2006. 40. Wylam JM, Mealey B, Mills MP, et al: The clinical effectiveness of open versus closed scaling and root planing on multi-rooted teeth. J Periodontol 64:1023, 1993.
Anatomy of The Bony Lesions Indices of Furcation Involvement Treatment
Nonsurgical Therapy Surgical Therapy Prognosis
For online-only content on root resection, hemisection, and root resection/hemisection procedure in the surgical therapy section, please visit the companion website at www.expertconsult.com. Some figures may be out of numeric order in this printed chapter. Editors Note: An animation (slide show) has been added as a supplement to the chapter by the Editors. This was produced by My Dental Hub as a patient education tool and covers the basic elements in a conceptual manner. It is not intended to be a procedural guide for dental professionals.
The progress of inflammatory periodontal disease, if unabated, ultimately results in attachment loss sufficient enough to affect the bifurcation or trifurcation of multirooted teeth. The furcation is an area of complex anatomic morphology5,6,11 that may be difficult or impossible to debride by routine periodontal instrumentation.29,36 Routine home care methods may not keep the furcation area free of plaque17,23 (see Video 62-1: Bone Loss with Furcation). The presence of furcation involvement is one clinical finding that can lead to a diagnosis of advanced periodontitis and potentially to a less-favorable prognosis for the affected tooth or teeth. Furcation involvement therefore presents both diagnostic and therapeutic dilemmas.
Etiologic Factors The primary etiologic factor in the development of furcation defects is bacterial plaque and the inflammatory consequences that result from its long-term presence. The extent of attachment loss required to produce a furcation defect is variable and related to local anatomic factors (e.g., root trunk length, root morphology)12,27 and local developmental anomalies (e.g., cervical enamel projections).22,27 Local factors may affect the rate of plaque deposition or complicate the performance of oral hygiene procedures, thereby contributing to the development of periodontitis and attachment loss. Studies indicate that prevalence and severity of furcation involvement increase with age.21,22,36 Dental caries and pulpal death may also affect a tooth with furcation involvement or even the area of the furcation. All of these factors should be considered during the diagnosis, treatment planning, and therapy of the patient with furcation defects.
Diagnosis and Classification of Furcation Defects A thorough clinical examination is the key to diagnosis and treatment planning. Careful probing is required to determine the presence and extent of furcation involvement, the position of the attachment relative to the furca, and the extent and configuration
of the furcation defect.38 The Nabors probe may be helpful to enter and measure difficult to access furcal areas (Figure 62-1). Transgingival sounding may further define the anatomy of the furcation defect.29 The goal of this examination is to identify and classify the extent of furcation involvement and to identify factors that may have contributed to the development of the furcation defect or that could affect treatment outcome. These factors include (a) the morphology of the affected tooth, (b) the position of the tooth relative to adjacent teeth, (c) the local anatomy of the alveolar bone, (d) the configuration of any bony defects, and (e) the presence and extent of other dental diseases (e.g., caries, pulpal necrosis). The dimension of the furcation entrance is variable but usually quite small; 81% of furcations have an orifice of l mm or less, and 58% are 0.75 mm or less.5,6 The clinician should consider these dimensions, and the local anatomy of the furcation area,11-13 when selecting instruments for probing. A probe of small cross-sectional dimension is required if the clinician is to detect early furcation involvement.
Local Anatomic Factors Clinical examination of the patient should allow the therapist to identify not only furcation defects but also many of the local anatomic factors that may affect the result of therapy (prognosis). Well-made dental radiographs, although not allowing a definitive classification of furcation involvement, provide additional information vital for treatment planning (Figure 62-2). Important local factors include anatomic features of the affected teeth, as described next.
Root Trunk Length A key factor in both the development and the treatment of furcation involvement is the root trunk length. The distance from the cementoenamel junction to the entrance of the furcation can vary extensively. Teeth may have very short root trunks, moderate root trunk length, or roots that may be fused to a point near the apex (Figure
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62-3). The combination of root trunk length with the number and configuration of the roots affects the ease and success of therapy. The shorter the root trunk, the less attachment needs to be lost before the furcation is involved. Once the furcation is exposed, teeth with short root trunks may be more accessible to maintenance procedures, and the short root trunks may facilitate some surgical procedures. Alternatively, teeth with unusually long root trunks or fused roots may not be appropriate candidates for treatment once the furcation has been affected.
Root Length Root length is directly related to the quantity of attachment ing the tooth. Teeth with long root trunks and short roots may have lost a majority of their by the time that the furcation becomes affected.13,20 Teeth with long roots and short-to-moderate root trunk length are more readily treated because sufficient attachment remains to meet functional demands.
Root Form The mesial root of most mandibular first and second molars and the mesiofacial root of the maxillary first molar are typically curved to the distal side in the apical third. In addition, the distal aspect of this root is usually heavily fluted. The curvature and fluting may increase the potential for root perforation during endodontic therapy or complicate post placement during restoration.1,25 These anatomic features may also result in an increased incidence of vertical root fracture. The size of the mesial radicular pulp may result in removal of most of this portion of the tooth during preparation.
Interradicular Dimension The degree of separation of the roots is also an important factor in treatment planning. Closely approximated or fused roots can preclude adequate instrumentation during scaling, root planing, and surgery. Teeth with widely separated roots present more treatment options and are more readily treated.
Anatomy of Furcation The anatomy of the furcation is complex. The presence of bifurcational ridges, a concavity in the dome,11 and possible accessory canals16 complicates not only scaling, root planing, and surgical therapy,28 but also periodontal maintenance. Odontoplasty to reduce or eliminate these ridges may be required during surgical therapy for an optimal result.
Cervical Enamel Projections Cervical enamel projections (CEPs) are reported to occur on 8.6% to 28.6% of molars.26,27,35 The prevalence is highest for mandibular and maxillary second molars. The extent of CEPs was classified by Masters and Hoskins27 in 1964 (Box 62-1). Figure 62-4 provides an example of a grade III CEP. These projections can affect plaque removal, can complicate scaling and root planing, and may be a local factor in the development of gingivitis and periodontitis. CEPs should be removed to facilitate maintenance.
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Anatomy of the Bony Lesions Pattern of Attachment Loss B Figure 62-1 A, The Nabors probe is designed to probe into the
furcation. B, The probe placed into a Class II furcation of a dried skull.
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The form of the bony lesions associated with the furcation can vary significantly. Horizontal bone loss can expose the furcation as thin facial/lingual plates of bone that may be totally lost during resorption. Alternatively, areas with thickened bony ledges may persist and predispose to the development of furcations with deep vertical components. The pattern of bone loss on other surfaces of the
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Figure 62-2 Different degrees of furcation involvement in radiographs. A, Grade I furcation on the mandibular first molar and a grade III furcation on the mandibular second molar. The root approximation on the second molar may be sufficient to impede accurate probing of this defect. B, Multiple furcation defects on a maxillary first molar. Grade I buccal furcation involvement and grade II mesiopalatal and distopalatal furcations are present. Deep developmental grooves on the maxillary second molar simulate furcation involvement in this molar with fused roots. C, Grades III and IV furcations on mandibular molars.
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BOX 62-1 Classification of Cervical Enamel Projections Grade I: The enamel projection extends from the cementoenamel junction of the tooth toward the furcation entrance. Grade II: The enamel projection approaches the entrance to the furcation. It does not enter the furcation, and therefore no horizontal component is present. Grade III: The enamel projection extends horizontally into the furcation. From Masters DH, Hoskins SW: J Periodontol 35:49, 1964.
Figure 62-5 Advanced bone loss, furcation involvement, and
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root approximation. Note the buccal furcation, which communicates with the distal furcation of a maxillary first molar that also displays advanced attachment loss on the distal root and approximation with the mesial root of the maxillary second molar. The patient with such teeth may benefit from root resection of the distobuccal root of the first molar or extraction of the molar.
Figure 62-3 Different anatomic features that may be important
in prognosis and treatment of furcation involvement. A, Widely separated roots. B, Roots are separated but close. C, Fused roots separated only in their apical portion. D, Presence of enamel projection that may be conducive to early furcation involvement.
development of a number of indices to record furcation involvement. These indices are based on the horizontal measurement of attachment loss in the furcation,14,17 on a combination of horizontal and vertical measurements,37 or a combination of these findings with the localized configuration of the bony deformity.10 Glickman14 classified furcation involvement into four grades (Figure 62-6).
Grade I A grade I furcation involvement is the incipient or early stage of furcation involvement (see Figure 62-6, A). The pocket is suprabony and primarily affects the soft tissues. Early bone loss may have occurred with an increase in probing depth, but radiographic changes are not usually found.
Grade II Figure 62-4 Furcation involvement by grade III cervical enamel
projections.
affected tooth and adjacent teeth must also be considered during treatment planning. The treatment response in deep, multiwalled bony defects is different from that in areas of horizontal bone loss. Complex multiwalled defects with deep, interradicular vertical components may be candidates for regenerative therapies. Alternatively, molars with advanced attachment loss on only one root may be treated by resective procedures.
Other Dental Findings The dental and periodontal condition of the adjacent teeth must be considered during treatment planning for furcation involvement. The combination of furcation involvement and root approximation with an adjacent tooth represents the same problem that exists in furcations without adequate root separation. Such a finding may dictate the removal of the most severely affected tooth or the removal of a root or roots (Figure 62-5). The presence of an adequate band of gingiva and a moderate to deep vestibule will facilitate the performance of a surgical procedure, if indicated.
Indices of Furcation Involvement The extent and configuration of the furcation defect are factors in both diagnosis and treatment planning. This has led to the
A grade II furcation can affect one or more of the furcations of the same tooth. The furcation lesion is essentially a cul-de-sac (see Figure 62-6, B) with a definite horizontal component. If multiple defects are present, they do not communicate with each other because a portion of the alveolar bone remains attached to the tooth. The extent of the horizontal probing of the furcation determines whether the defect is early or advanced. Vertical bone loss may be present and represents a therapeutic complication. Radiographs may or may not depict the furcation involvement, particularly with maxillary molars because of the radiographic overlap of the roots. In some views, however, the presence of furcation “arrows” indicates possible furcation involvement (see Chapter 31).
Grade III In grade III furcations, the bone is not attached to the dome of the furcation. In early grade III involvement, the opening may be filled with soft tissue and may not be visible. The clinician may not even be able to a periodontal probe completely through the furcation because of interference with the bifurcational ridges or facial/ lingual bony margins. However, if the clinician adds the buccal and lingual probing dimensions and obtains a cumulative probing measurement that is equal to or greater than the buccal/lingual dimension of the tooth at the furcation orifice, the clinician must conclude that a grade III furcation exists (see Figure 62-6, C). Properly exposed and angled radiographs of early Class III furcations
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Figure 62-6 Glickman’s classification of furcation involvement. A, Grade I furcation involvement. Although a space is visible at the entrance to the furcation, no horizontal component of the furcation is evident on probing. B, Grade II furcation in a dried skull. Note both the horizontal and the vertical component of this cul-de-sac. C, Grade III furcations on maxillary molars. Probing confirms that the buccal furcation connects with the distal furcation of both these molars, yet the furcation is filled with soft tissue. D, Grade IV furcation. The soft tissues have receded sufficiently to allow direct vision into the furcation of this maxillary molar.
display the defect as a radiolucent area in the crotch of the tooth (see Chapter 31).
Grade IV In grade IV furcations, the interdental bone is destroyed, and the soft tissues have receded apically so that the furcation opening is clinically visible. A tunnel therefore exists between the roots of such an affected tooth. Thus the periodontal probe es readily from one aspect of the tooth to another (see Figure 62-6, D).
Other Classification Indices Hamp et al17 modified a three-stage classification system by attaching a millimeter measurement to separate the extent of horizontal involvement. Easley and Drennan10 and Tarnow and Fletcher37 have described classification systems that consider both horizontal and vertical attachment loss in classifying the extent of furcation involvement. The Tarnow and Fletcher article utilizes a subclassification that measures the probeable vertical depth from the roof of the furca apically. The subclasses being proposed are: A, B, and C. “A” indicates a probeable vertical depth of 1 to 3 mm, “B” indicates 4 to 6 mm, and “C” indicates 7 or more mm of probeable depth from the roof of the furca apically. Furcations would thus be classified as IA, IB, and IC; IIA, IIB, and IIC; and IIIA, IIIB, and IIIC. Consideration of defect configuration and the vertical component of the defect provides additional information that is useful in planning therapy.
Treatment The objectives of furcation therapy are to (a) facilitate maintenance, (b) prevent further attachment loss, and (c) obliterate the furcation defects as a periodontal maintenance problem. The
selection of therapeutic mode varies with the class of furcation involvement, the extent and configuration of bone loss, and other anatomic factors.
Therapeutic Classes of Furcation Defects Class I: Early Defects. Incipient or early furcation defects
(Class I) are amenable to conservative periodontal therapy.15 Because the pocket is suprabony and has not entered the furcation, oral hygiene, scaling, and root planing are effective.16 Any thick overhanging margins of restorations, facial grooves, or CEPs should be eliminated by odontoplasty, recontouring, or replacement. The resolution of inflammation and subsequent repair of the periodontal ligament and bone are usually sufficient to restore periodontal health.
Class II. Once a horizontal component to the furcation has devel-
oped (Class II), therapy becomes more complicated. Shallow horizontal involvement without significant vertical bone loss usually responds favorably to localized flap procedures with odontoplasty, osteoplasty, and ostectomy. Isolated deep Class II furcations may respond to flap procedures with osteoplasty and odontoplasty (Figure 62-7). This reduces the dome of the furcation and alters gingival contours to facilitate the patient’s plaque removal.
Classes II to IV: Advanced Defects. The development of
a significant horizontal component to one or more furcations of a multirooted tooth (late Class II, Class III, or Class IV13) or the development of a deep vertical component to the furca poses additional problems. Nonsurgical treatment is usually ineffective because the ability to instrument the tooth surfaces adequately is compromised.31,40 Periodontal surgery, endodontic therapy, and restoration of the tooth may be required to retain the tooth.
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Figure 62-7 Treatment of a grade II furcation by osteoplasty and odontoplasty. A, This mandibular first molar has been treated endodontically and an area of caries in the furcation repaired. A Class II furcation is present. B, Results of flap debridement, osteoplasty, and severe odontoplasty 5 years postoperatively. Note the adaptation of the gingiva into the furcation area. (Courtesy Dr. Ronald Rott, Sacramento, CA.)
Nonsurgical Therapy Oral Hygiene Procedures Furcal management is difficult at best. Therapeutic modalities for the treatment and maintenance of furcations have long been a dilemma amongst periodontists and restorative dentists. Nonsurgical therapy is a very effective way of producing a satisfactory stable result. Ideal results with furcations are impossible to obtain. Once furcation breakdown has begun, there is always a somewhat compromised result clinically. Both surgical and nonsurgical therapies have been shown to work effectively over time. Nonsurgical therapy, a combination of oral hygiene instruction and scaling and root planing, has provided excellent results in some patients. The earlier the furcation is detected and treated the more likely a good long-term result can be obtained. Nonetheless, even advanced furcation lesions can have successful long-term treatment.34 Several oral hygiene procedures have been used over time. All include access to the furcation. Obtaining access to the furcation requires a combination of the awareness of the furcation by the patient and an oral hygiene tool that facilitates that access. Many tools, including rubber tips; periodontal aids; toothbrushes, both specific and general; and other aids have been used over time for access to the patient (Figure 62-8).
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Scaling and Root Planing Nonsurgical maintenance by the clinician has also improved over time as instrumentation has improved. In recent decades, instruments beyond simple curettes have been used to instrument the furcation. The frustration of instrumentation of the furcation was illustrated beautifully by Bower in 1979 in his articles5,6 showing that only 58% of furcations could be entered by typically using curettes (see Chapter 33). Subsequently, other instrumentation has evolved, including DeMarco curettes, diamond files, Quetin furcation curettes, and mini Five Gracey Curettes. See Chapter 46 for a detailed discussion on this subject. Svärdström and Wennström34 illustrated that in the long term, furcations could be maintained using nonaggressive techniques over a 10-year period in patients who were participants in consistent maintenance. Other studies also illustrate that maintenance therapy is useful for patients to facilitate furcation cleanliness. Chemotherapy has proven disappointing. Ribeiro et al32 found that nonsurgical therapy can effectively treat Class II furcation involvements, but using povidone-iodine did not provide additional benefits to subgingival instrumentation.
B Figure 62-8 A, The utilization of a Perio-Aid into the furcation for
plaque removal. B, Proxy brush is used for plaque removal into the furcation lesion. (Courtesy Karen DeYoung, RDH, and Janet Shigekawa, RDH.)
The area most critical in furcation management is maintaining a relatively plaque-free status to the furcation. Attaining access is a problem in this regard, but with the previously mentioned instruments and an effective nonsurgical approach, much can be accomplished. The most critical component of multirooted tooth maintenance is always the successful reduction or elimination of plaque retention areas from the furcation area; meticulous oral hygiene by the patient and an effective nonsurgical therapy can play a major role in attaining this goal.21,33
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Surgical Therapy Osseous Resection Osseous surgical therapy can be divided into resective and regenerative therapy. This also applies to the furcation areas when surgical therapy is contemplated. For many years, osteoplasty and ostectomy have been used to make the furcation areas cleansable. In the advanced cases, techniques were used to open the furcation into a Class IV from a severe Class II or III case. This would allow easier hygiene into the furcation area for the patient. These techniques have limited usefulness today, but in the compromised individual in whom teeth cannot be extracted or in whom conservative therapy has failed, these surgical techniques have been used. The immediate goal with these surgical approaches is to create access for the patient to maintain good hygiene.
Regeneration In furcal lesions, bone regeneration is often thought to be relatively futile. The periodontal literature has well-documented therapeutic efforts designed to induce new attachment and reconstruction on molars with furcation defects. Many surgical procedures using a variety of grafting materials have been tested on teeth with different classes of furcation involvement. Some investigators have reported clinical success,24 whereas others have suggested that the use of these materials in Class II, III, or IV furcations offers little advantage compared with surgical controls.3,9,30 Furcation defects with deep two-walled or three-walled components may be suitable for reconstruction procedures. These vertical bony deformities respond favorably to a variety of surgical procedures, including debridement with or without membranes and bone grafts. Chapter 61 addresses therapies designed to induce new attachment or reattachment. Tsao et al39 have shown that the furcation defect is a graftable lesion. They found that lesions that were grafted had greater vertical fill than areas treated with open flap debridement alone. Bowers et al7 have shown furcation bone grafting using various membranes can improve the clinical status of these lesions. Nonetheless, bone grafting remains an elusive goal with variable results in furcation lesions. Another area of interest has been barrier membrane technology. Analysis of published studies demonstrated a great variability in the clinical outcomes in mandibular grade II furcations treated with different types of nonbioabsorbable and bioabsorbable barrier membranes. Although many barrier membrane studies show a slight clinical improvement after treatment in both maxillary and mandibular furcations, the results are generally inconsistent.
Extraction The extraction of teeth with through-and-through furcation defects (Classes III and IV) and advanced attachment loss may be the most appropriate therapy for some patients. This is particularly true for individuals who cannot or will not perform adequate plaque control, who have a high level of caries activity, who will not commit to a suitable maintenance program, or who have socioeconomic factors that may preclude more complex therapies. Some patients are reluctant to accept periodontal surgery or even allow the removal of a tooth with advanced furcation involvement, even though the long-term prognosis is poor. The patient may elect to forego therapy, opt to treat the area with scaling and root planing or site-specific antibacterial therapies, and delay extraction until the tooth becomes symptomatic. Although additional attachment loss may occur, such teeth may survive a significant number of years.21,33
Dental Implants The advent of osseointegrated dental implants as an alternative abutment source has had a major impact on the retention of teeth with advanced furcation problems. The high level of predictability of osseointegration may motivate the therapist and patient to consider removal of teeth with a guarded or poor prognosis and to seek an implant-ed prosthetic treatment plan. Therefore careful evaluation of the long-term periodontal, endodontic, and restorative prognosis must be considered before invasive surgical therapy is undertaken to save a tooth with an advanced furcated lesion (Figure 62-15).
Prognosis For many years the presence of significant furcation involvement meant a hopeless long-term prognosis for the tooth. Clinical research, however, has indicated that furcation problems are not as severe a complication as originally suspected if one can prevent the development of caries in the furcation. Relatively simple periodontal therapy is sufficient to maintain these teeth in function for long periods.21,33 Other investigators have defined the reasons for clinical failure of root-resected or hemisected teeth.2,25 Their data indicate that recurrent periodontal disease is not a major cause of the failure of these teeth. Investigations of root-resected or hemisected teeth have shown that such teeth can function successfully for long periods.2,8,25 The keys to long-term success appear to be (a) thorough diagnosis, (b) selection of patients with good oral hygiene, (c) excellence in nonsurgical therapy, and (d) careful surgical and restorative management.
CHAPTER 62 Furcation: Involvement and Treatment
Root Resection Root resection may be indicated in multirooted teeth with grades II to IV furcation involvements. Root resection may be performed on vital teeth19 or endodontically treated teeth. It is preferable, however, to have endodontic therapy completed before resection of a root(s).18 If this is not possible, the pulp should be removed, the patency of the canals determined, and the pulp chamber medicated before resection. It is distressing for both patient and clinician to perform a vital root resection and subsequently have an unfavorable event occur, such as perforation, fracture of the root, or an inability to instrument the canal. The indications and contraindications for root resection were well summarized by Bassaraba.1 In general, teeth planned for root resection include the following: 1. Teeth that are critically important to the overall dental treatment plan.4 Examples are teeth serving as abutments for fixed or removable restorations for which loss of the tooth would result in loss of the prosthesis and entail major prosthetic retreatment. 2. Teeth that have sufficient attachment remaining for function. Molars with advanced bone loss in the interproximal and interradicular zones, unless the lesions have three bony walls, are not candidates for root amputation. 3. Teeth for which a more predictable or cost-effective method of therapy is not available. Examples are teeth with furcation defects that have been treated successfully with endodontics but now present with a vertical root fracture, advanced bone loss, or caries on the root. 4. Teeth in patients with good oral hygiene and low activity for caries are suitable for root resection. Patients unable or unwilling to perform good oral hygiene and preventive measures are not suitable candidates for root resection or hemisection. Rootresected teeth require endodontic treatment18 and usually cast restorations. These therapies can represent a sizable financial investment by the patient in an effort to save the tooth. Alternative therapies and their impact on the overall treatment plan should always be considered and presented to the patient.
Which Root to Remove. A tooth with an isolated furcation defect in an otherwise intact dental segment may present few diagnostic problems. However, the existence of multiple furcation defects of varying severity combined with generalized advanced periodontitis can be a challenge to treatment planning. Careful diagnosis usually allows the therapist to determine the feasibility of root resection and the identification of which root to remove before surgery (Figure 62-9). Every attempt should be made to determine this prior to surgical exposure. The following is a guide to determining which root should be removed in these cases: 1. Remove the root(s) that will eliminate the furcation and allow the production of a maintainable architecture on the remaining roots. 2. Remove the root with the greatest amount of bone and attachment loss. Sufficient periodontal attachment must remain after surgery for the tooth to withstand the functional demands placed on it such as bridge abutments and in bruxers. Teeth with uniform advanced horizontal bone loss are not suitable for root resection. 3. Remove the root that best contributes to the elimination of periodontal problems on adjacent teeth. For example, a maxillary first molar with a Class III buccal-to-distal furcation is
626.e1
adjacent to a maxillary second molar with a two-walled intrabony defect between the molars and an early Class II furcation on the mesial furcation of the second molar. There may or may not be local anatomic factors affecting the teeth. The removal of the distobuccal root of the first molar allows the elimination of the furcation and management of the two-wall intrabony lesion and also facilitates access for instrumentation and maintenance of the second molar. 4. Remove the root with the greatest number of anatomic problems such as severe curvature, developmental grooves, root flutings, or accessory and multiple root canals. 5. Remove the root that least complicates future periodontal maintenance.
Hemisection Hemisection is the splitting of a two-rooted tooth into two separate portions. This process has been called bicuspidization or separation because it changes the molar into two separate roots. Hemisection is most likely to be performed on mandibular molars with buccal and lingual Class II or III furcation involvements. As with root resection, molars with advanced bone loss in the interproximal and interradicular zones are not good candidates for hemisection. After sectioning of the teeth, one or both roots can be retained. This decision is based on the extent and pattern of bony loss, root trunk and root length, ability to eliminate the osseous defect, and endodontic and restorative considerations. The anatomy of the mesial roots of mandibular molars often leads to their extraction and the retention of the distal root to facilitate both endodontic and restorative therapy. The interradicular dimension between the two roots of a tooth to be hemisected is also important. Narrow interradicular zones can complicate the surgical procedure. The retention of both molar roots can complicate the restoration of the tooth, since it may be virtually impossible to finish margins or to provide an adequate embrasure between the two roots for effective oral hygiene and maintenance (Figure 62-10). Therefore, orthodontic separation of the roots is often required to allow restoration with adequate embrasure form (Figure 62-11). The result can be the need for multiple procedures and extensive interdisciplinary therapy. In these patients the availability of other treatment alternatives should be considered such as guided tissue/guided bone regeneration or replacement by osseointegrated dental implants.
Root Resection/Hemisection Procedure The most common root resection involves the distobuccal root of the maxillary first molar,2,26 as diagrammed in Figure 62-12. After appropriate local anesthesia, a full-thickness mucoperiosteal flap is elevated. Root resection or hemisection of teeth with advanced attachment loss usually requires opening both facial and lingual/ palatal flaps (see Chapter 57). Typically, a root cannot be resected without elevating a flap. The flap should provide adequate access for visualization and instrumentation and minimize surgical trauma. After debridement, resection of the root begins with the exposure of the furcation on the root to be removed (see Figure 62-12, A). The removal of a small amount of facial or palatal bone may be required to provide access for elevation and facilitate root removal (see Figure 62-12, B). A cut is then directed from just apical to the point of the tooth, through the tooth, and to the facial and distal orifices of the furcation (see Figure 62-12, C). This cut is made with a high-speed, surgical-length fissure or crosscut fissure carbide bur. The placement of a curved periodontal probe into or through the furcation aids in orienting the angle of the resection. For hemisection, a vertically oriented cut is made
626.e2
PART 2 Clinical Periodontics
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Figure 62-9 Resection of a root with advanced bone loss. A, Facial osseous contours. There is an early grade II furcation on the facial
aspect of the mandibular first molar and a Class III furcation on the mandibular second molar. B, Resection of the mesial root. The mesial portion of the crown was retained to prevent mesial drift of the distal root during healing. The grade II furcations were treated by osteoplasty. C, Buccal flaps adapted and sutured. D, Lingual flaps adapted and sutured. E, Three-month postoperative view of the buccal aspect of this resection. New restorations were subsequently placed. F, Three-month postoperative view of the lingual aspect of this resection.
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Figure 62-10 A, Grade III furcation lesion. B, Hemisection to divide the tooth into mesial and distal portions. C, Postoperative view of a
hemisected mandibular with new crowns for both roots.
CHAPTER 62 Furcation: Involvement and Treatment
A
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626.e3
Figure 62-11 Hemisection and interradicular dimension. A, Buccal preoperative view of a mandibular right second molar with a deep
grade II buccal furcation and root approximation. B, Buccal view of bony lesions with flaps. Note the mesial and distal one-wall bony defects. The lingual furcation was similarly affected. C, The molar has been hemisected and partially prepared for temporary crowns. Observe the minimal dimension between the two roots. D, Buccal view 3 weeks postoperatively. Because the embrasure space is minimal, these roots will be separated with orthodontic therapy to facilitate restoration. (Courtesy Dr. Louis Cuccia, Roseville, CA.)
faciolingually through the buccal and lingual developmental grooves of the tooth, through the pulp chamber, and through the furcation. If the sectioning cut es through a metallic restoration, the metallic portion of the cut should be made before flap elevation. This prevents contamination of the surgical field with metallic particles. If a vital root resection is to be performed, a more horizontal cut through the root is advisable (see Figure 62-12, D). An oblique cut exposes a large surface area of the radicular pulp and/or dental pulp chamber. This can lead to postoperative pain and can complicate endodontic therapy. A horizontal cut, although it may complicate root removal, has fewer postoperative complications. This root stump can be removed by odontoplasty after the completion of endodontic therapy or at the time of tooth preparation. After sectioning, the root is elevated from its socket (see Figure 62-12, E). Care should be taken not to traumatize bone on the remaining roots or to damage an adjacent tooth. Removal of the root provides visibility to the furcation aspects of the remaining roots and simplifies the debridement of the furcation with hand, rotary, or ultrasonic instruments. If necessary, odontoplasty is performed to
remove portions of the developmental ridges and prepare a furcation that is free of any deformity that would enhance plaque retention or adversely affect plaque removal (see Figure 62-12, F). Patients with advanced periodontitis often have root resection performed in conjunction with other surgical procedures. Figure 68-13 provides an example of combining root resection and periodontal osseous surgery. The bony lesions that may be present on adjacent teeth are then treated using resective or regenerative therapies. After resection, the flaps are then approximated to cover any grafted tissues or slightly cover the bony margins around the tooth. Sutures are then placed to maintain the position of the flaps. The area may or may not be covered with a surgical dressing. The removal of a root alters the distribution of occlusal forces on the remaining roots. Therefore, it is wise to evaluate the occlusion of teeth from which roots have been resected and, if necessary, adjust the occlusion. Centric holds should be maintained, but eccentric forces should be eliminated from the area over the root that was removed. Patients with advanced attachment loss may benefit from temporary stabilization of the resected tooth to prevent movement (Figure 62-14).
626.e4
PART 2 Clinical Periodontics
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Figure 62-12 Diagrams of distobuccal root resection of maxillary first molar. A, Preoperative bony contours with grade II buccal furca-
tion and a crater between the first and second molar. B, Removal of bone from the facial side of the distobuccal root and exposure of the furcation for instrumentation. C, Oblique section that separates the distal root from the mesial and palatal roots of the molar. D, More horizontal section that may be used on a vital root amputation because it exposes less of the pulp of the tooth. E, Areas of application of instruments to elevate the sectioned root. F, Final contours of the resection.
CHAPTER 62 Furcation: Involvement and Treatment
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626.e5
Figure 62-13 Hemisection combined with osseous surgery to treat furcation defects. A, Buccal preoperative view with provisional
bridge. B, Lingual view with provisional bridge in place. C, Radiograph of bony defects. Note the deep mesial bony defect, largely of one wall, and the radiolucent area in the furcation of the first molar, indicating a grade II defect. D, Buccal view before osseous surgery. In addition to the furcation involvement, a root separation problem exists between the two roots of the first molar. Class II furcations are present on the second molar. E, Buccal view after osseous surgery. Mesial root hemisected and removed. The other defects were treated by osteoplasty and ostectomy. F, Lingual preoperative view. Note the heavy bony ledging at the lingual surface of these first and second molars. G, Lingual postoperative view. The mesial root has been resected, the bony ledging recontoured, and the grade II furcations treated by osteoplasty. H, Buccal view 10 years after treatment. I, Lingual view 10 years after treatment. (Courtesy Dr. Louis Cuccia, Roseville, CA.)
626.e6
PART 2 Clinical Periodontics
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Figure 62-14 Mesial root resection in the presence of advanced bone loss. A and B, Buccal and lingual preoperative views. Note the
soft-tissue contours that are predictive of the bony defects. C, Radiograph of extent of furcation involvement of the first and second molars. D and E, Buccal preoperative and postoperative views. The mesial root of the second molar was resected and the interproximal craters treated by osteoplasty and minor ostectomy. F and G, Lingual preresection and postresection views. The heavy ledges and horizontal bone loss on the lingual surface were managed by osteoplasty. H and I, Buccal and lingual views 6 weeks postoperatively. A temporary wire splint has been bonded to the molars to prevent tipping of the distal root of the mandibular second molar. (Courtesy Dr. Louis Cucci, Roseville, CA.)
CHAPTER 62 Furcation: Involvement and Treatment
627
A B
0 b
11.7 6.3
D
C Figure 62-15 A, Clinical picture of a Class III furcation involvement. B, Radiographic appearance is far more grave than the clinical appearance. C, After the tooth is removed, a computed tomography (CT) radiograph is taken to plan treatment for implant replacement. D, The implant restored. (Courtesy Dr. Sarvenaz Angha, Los Angeles.)
Suggested Readings DeSanctis M, Murphy KG: The role of resective periodontal surgery in the treatment of furcation defects. J Periodontol 22:154–168, 2000. Newell DH: The diagnosis and treatment of molar furcation invasions. Dent Clin North Am 42(2):301–337, 1998.
References References for this chapter are found on the companion website www.expertconsult.com.
CHAPTER 62 Furcation: Involvement and Treatment
References 1. Bassaraba N: Root amputation and tooth hemisection. Dent Clin North Am 13:121, 1969. 2. Basten CH, Ammons WF, Persson R: Long-term evaluation of root resected molars: a retrospective study. Int J Periodont Restor Dent 16(3):207, 1996. 3. Becker W, Becker BE, Berg L, et al: New attachment after treatment with root isolation procedures: report for treated class III and class II furcations and vertical osseous defects. Int J Periodont Restor Dent 8(3):9, 1988. 4. Black GV: The American system of dentistry, Philadelphia, 1886, Lea Brothers. 5. Bower RC: Furcation morphology relative to periodontal treatment: furcation root surface anatomy. J Periodontol 50:366, 1979. 6. Bower RC: Furcation morphology relative to periodontal treatment: furcation entrance architecture. J Periodontol 50:23, 1979. 7. Bowers GM, Schallhorn RG, McClain PK, et al: Factors influencing the outcome of regenerative therapy in mandibular class II furcations: part I. J Periodontol 74(9):1255–1268, 2003. 8. Carnevale G, DiFebo G, Toyelli MP, et al: A retrospective analysis of the periodontal-prosthodontic treatment of molars with interradicular lesions. Int J Periodont Restor Dent 11:188, 1991. 9. Demolon IA, Person GR, Ammons WF, et al: Effects of antibiotic treatment on clinical conditions with guided tissue regeneration: oneyear results. J Periodontol 65:713, 1994. 10. Easley JR, Drennan GA: Morphological classification of the furca. J Can Dent Assoc 35:104, 1969. 11. Everett F, Jump E, Holder T, et al: The intermediate bifurcational ridge: a study of the morphology of the bifurcation of the lower molar. J Dent Res 37:162, 1958. 12. Gher ME, Vernino AR: Root morphology: clinical significance in pathogenesis and treatment of periodontal disease. J Am Dent Assoc 101:627, 1980. 13. Gher ME, Jr, Dunlap RW: Linear variation of the root surface area of the maxillary first molar. J Periodontol 56:39, 1985. 14. Glickman I: Clinical periodontology, Philadelphia, 1953, Saunders. 15. Goldman HM: Therapy of the incipient bifurcation involvement. J Periodontol 29:112, 1958. 16. Gutmann JL: Prevalence, location and patency of accessory canals in the furcation region of permanent molars. J Periodontol 49:21, 1978. 17. Hamp SE, Nyman S, Lindhe J: Periodontal treatment of multirooted teeth. Results after 5 years. J Clin Periodontol 2:126, 1975. 18. Harrington GW: The perio-endo question: differential diagnosis. Dent Clin North Am 23:673, 1979. 19. Haskell EW, Stanley HR: A review of vital root resection. Int J Periodont Restor Dent 2(6):29, 1982. 20. Hermann DW, Gher ME, Jr, Dumlap RM, et al: The potential attachment area of the maxillary first molar. J Periodontol 54:431, 1983. 21. Hirschfeld L, Wasserman B: A long-term survey of tooth loss in 600 treated periodontal patients. J Periodontol 49:225, 1978.
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22. Hou GL, Tasai CC: Relationship between periodontal furcation involvement and molar cervical enamel projection. J Periodontol 58:715, 1978. 23. Kalkwarf K, Kaldahl W, Patil K, et al: Evaluation of furcation region response to periodontal therapy. J Periodontol 59:794, 1988. 24. Kenney EB, Lekovic V, Elbaz JJ, et al: The use of porous hydroxylapatite implants in periodontal defects. II. Treatment of class II furcation lesions in lower molars. J Periodontol 59:67, 1988. 25. Langer B, Stein SD, Wagenberg B: An evaluation of root resections: a ten-year study. J Periodontol 52:719, 1981. 26. Larato DC: Some anatomical factors related to furcation involvement. J Periodontol 46:608, 1975. 27. Masters DH, Hoskins SW: Projection of cervical enamel into molar furcations. J Periodontol 35:49, 1964. 28. Matia JB, Bissada NF, Maybury JE, et al: Efficiency of scaling of the molar furcation area with and without surgical access. Int J Periodont Restor Dent 6(6):25, 1986. 29. Mealy BL, Beybayer MF, Butzin CA, et al: Use of furcal bone sounding to improve accuracy of furcation diagnosis. J Periodontol 65:649, 1994. 30. Metzler DG, Seamons BC, Mellonig JT, et al: Clinical evaluation of guided tissue regeneration in the treatment of maxillary class II molar furcation. J Periodontol 62:353, 1991. 31. Parashis AO, Anognou-Vareltzides A, Demetrious N: Calculus removal from multirooted teeth with and without surgical access. I. Efficacy on external and furcation surfaces in relation to probing depth. J Clin Periodontol 20:63, 1993. 32. Ribeiro EDP, Bittencourt S, Ambrosano GMB, et al: Povidone-iodine used as an adjunct to non-surgical treatment of furcation involvements. J Periodontol 77(2):211–217, 2006. 33. Ross I, Thompson RH: A long-term study of root retention of maxillary molars with furcation involvement. J Periodontol 49:238, 1978. 34. Svärdström G, Wennström J: Periodontal treatment decisions for molars: an analysis of influencing factors and long-term outcome. J Periodontol 71(4):579–585, 2000. 35. Tal H: Furcal bony defects in dry mandibles. I. Biometric study. J Periodontol 53:360, 1982. 36. Tal H, Lemmer J: Furcal defects in dry mandibles. II. Severity of furcal defects. J Periodontol 53:364, 1982. 37. Tarnow D, Fletcher P: Classification of the vertical component of furcation involvement. J Periodontol 55:283, 1984. 38. Tibbetts LF: Use of diagnostic probes for detection of periodontal disease. J Am Dent Assoc 78:549, 1969. 39. Tsao Y, Neiva R, Al-Shammari K, et al: Factors influencing treatment outcomes in mandibular class II furcation defects. J Periodontol 77(4):641–646, 2006. 40. Wylam JM, Mealey B, Mills MP, et al: The clinical effectiveness of open versus closed scaling and root planing on multi-rooted teeth. J Periodontol 64:1023, 1993.
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