Periodontal implications of furcation entrance dimensions in Chinese first permanent molars

Narrow dimensions of the entrance to furcations of multi-rooted teeth can complicate the periodontal management of furcation involvements. The objectives of this study were to measure the furcation entrance dimensions of first permanent molars from Hong Kong Chinese, and to compare these dimensions with those of the blade widths of periodontal instruments generally advocated for root surface instrumentation. A total of 363 first permanent molars, of which 185 were maxillary, were examined under 1.5 x magnification. Furcation entrance dimensions were measured using calibrated test gauges ranging from 0.3 mm to 1.5 mm. Furcation entrance dimensions equal to or less than 0.75 mm (the blade width of a new Gracey curet being 0.76 mm) in maxillary first molars were found in 79% of buccal entrances, 39% of mesial entrances, and 43% of distal entrances. In mandibular first molars, entrance dimensions equal to or less than 0.75 mm were encountered in 36% and 47% of buccal and lingual furcation entrances respectively. One-half of all furcation entrance dimensions of these first molars were less than the blade width of new Gracey curets. This high prevalence of narrow furcation entrances should be considered in the periodontal management of furcation involvement of first molars in Chinese.     

Biometric analysis of the maxillary permanent molar teeth and its relation to furcation involvement

A high rate of root exposure and consequently the exposure of the furcation area is usually observed in multirooted teeth. In maxillary molar teeth, this fact may endanger the three existent furcations (buccal, mesial and distal), causing serious problems. In this research, distance measures from the buccal furcation to the mesial (F1M) and distal (F1D) surfaces of the mesio-buccal and disto-buccal roots; from the mesial furcation to the buccal (F2B) and palatal (F2P) surfaces of the mesio-buccal and palatal roots and from the distal furcation to the buccal (F3B) and palatal (F3P) surfaces of the disto-buccal and palatal roots, respectively were established. One hundred maxillary first molar teeth were used, 50 of the right and 50 of the left side. Reference marks and demarcations were determined on the furcations and also on the root surfaces involved in the measures. We concluded that these measurements are important because they may effectivelly contribute to diagnosis, prevention and treatment of periodontal problems.     

The topography of the furcation entrance in Chinese molars

Abstract The purpose of the present study was to document the furcation entrance dimensions (FEDs) of the maxillary and mandibular 1st and 2nd molars and relate them to the choice of periodontal therapy. Study samples consisted of 89 maxillary molars (49 1st and 40 2nd molars) and 93 mandibular molars (50 1st and 43 2nd molars). All the FEDs of the molars were examined and measured under a stereomicroscope at 2.5 × equipped with a Bioscan OPTIMAS Image Analyzer (BOIA). The results may be summarized as follows. (1) The mean FEDs in the buccal, distal and mesial furcations of maxillary 1 st and 2nd molars were 0.74 mm, 0.99 mm and 1.04 mm in the 1st molars, and 0.63 mm, 0.67 mm, 0.90 mm in the 2nd molars, respectively. In the buccal and lingual furcations of mandibular 1st and 2nd molars, they measured 0.88 mm and 0.81 mm, and 0.73 mm and 0.71 mm, respectively. (2) The %s of FEDs of 0.56 mm or less (the tip width of a Cavitron tip being 0.56 mm) in the buccal, distal and mesial furcations of maxillary 1st and 2nd molars, accounted for 32%, 8% and 6% of 1st molars, and 40%, 40% and 18% of 2nd molars. In the buccal and lingual areas of mandibular 1st and 2nd molars, they accounted for 16% and 26%, and 35% and 33% of the furcations, respectively. (3) The %s of FEDs of 0.75 mm or less (the width of curettes being 0.75–1.0 mm) in the buccal, mesial and distal furcations of maxillary 1st and 2nd molars accounted for 57%, 18% and 43% of 1st molar furcations, and 83%, 43% and 65% of 2nd molar furcations, respectively. In the buccal and lingual areas of mandibular 1st and 2nd molars, they accounted for 36% and 52%, and 63% and 61% of the furcations, respectively. (4) The majority of mean FEDs in 2nd molars were less than the blade width of new Gracey curettes, whereas in 1st molars they were similar to the blade width of unused Gracey curettes. (5) Most mean FEDs in 1st and 2nd molars were greater than the width of unused Cavitron tips. (6) To achieve complete debridement of root surfaces within furcations, an appropriate selection and combination of Cavitron tips and periodontal curettes should be considered.     

The "furcation arrow". A reliable radiographic image?

When radiographs of maxillary molars are observed, a small, triangular radiographic shadow is sometimes noted over either the mesial or distal roots in the proximal furcation area. This study was undertaken to determine the reliability of using this radiographic image as an aid in diagnosing proximal furcation involvement. Sixty-six Degree 1, 53 Degree 2 and 43 Degree 3 proximal furcation involvements in maxillary molars in dry skulls were assessed visually with the Nyman and Lindhe classification. An additional 120 uninvolved furcations were included as controls. The involved maxillary molars were radiographed with standard periapical radiographic techniques. Projected radiographs were evaluated independently by six dentists who determined whether there was a triangular radiographic shadow ("furcation arrow") over the mesial and distal proximal areas. The association of the furcation arrow image with Degree 2 or 3 furcation involvement was significant when compared with uninvolved furcations. The image was equally apparent over mesial or distal furcations and was not affected by the existence of a buccal furcation involvement. The incidence of the image over both uninvolved proximal furcations and proximal furcations with Degree 1 involvement was low and did not differ significantly. Because the furcation arrow seldom appears over uninvolved furcations, the appearance of the image indicates that there is proximal bony furcation involvement. However, absence of the furcation arrow image does not necessarily mean absence of a bony furcation involvement because the arrow was not seen in a large number of furcations with Degree 2 or 3 involvement.     

Periodontal Probing of Dental Furcations Compared With Diagnosis by Low‐Dose Computed Tomography: A Case Series

Background: Therapeutic decisions in periodontal surgery are based on the accurate diagnosis of the furcation. Clinical probing is the basic diagnostic tool; however, the accuracy of clinical probing to distinguish Class II and Class III furcation defects is unknown. Therefore, this study compares clinical probing diagnoses to those of computed tomography (CT). Methods: Seventy‐five patients with severe periodontal disease were enrolled in this case series study. A total of 582 furcation sites in molars were assigned for the diagnosis of Class II and Class III furcation defects by clinical probing. Diagnosis based on CT served as a reference. Results: The degree of furcation involvement on clinical findings was confirmed in 57% of the sites, whereas 20% were overestimated and 23% were underestimated compared with the radiologic analysis. Only 32% of Class III furcations in the CT scan were detected clinically. The best correlation of CT scan and clinical probing was found at buccal furcation sites in the mandible, with a κ‐coefficient of 0.52, and buccal furcation sites in the maxilla, κ = 0.38. The κ‐coefficient was 0.35 for lingual furcations, 0.29 for mesial furcations, and 0.27 for distal furcations, showing weaker correlations. Conclusions: CT scans offer more detailed information on furcation involvement than clinical probing. Especially before surgical treatment, three‐dimensional radiographic imaging can be a useful tool to assess the degree of furcation involvement and optimize treatment decisions.     

Guided tissue regeneration in the treatment of degree II furcations in maxillary molars

Abstract The present clinical trial was designed to evaluate the clinical effect of GTR in the treatment of degree II furcation defects in maxillary molars. 28 patients, 21 to 59 years of age, referred for treatment of advanced periodontal disease were included. They presented with similar periodontal lesions in the right and the left maxillary molar regions, but had only one surface which exhibited furcation involvement. A total of 28 pairs of contralateral furcation defects of degree II including 18 interproximal pairs (10 mesial, 8 distal) and 10 buccal pairs, were available for the study. After the completion of basic therapy, the furcation involved molars in the right and left quadrants in each patient were randomly assigned to either a test or a control treatment procedure. Following flap elevation, scaling, root planing and granulation tissue removal, an e-PTFE membrane at the test site was adjusted to cover the entrance to the furcation defect and adjacent bone and was retained in this position with sling sutures. The mucoperiostal flaps were subsequently adjusted and positioned to cover the entire surface of the membrane and were secured in this position. An identical surgical procedure was performed in the control tooth regions with the exception of the placement of a teflon membrane. No periodontal dressing was used. Starting the day before surgery and continuing for 7 days, the patients received 1 + 1 g of Amoxicillin per day; morning and evening. The sutures were removed after 10 days. At the test sites, the membranes were removed after 6 weeks of healing. The treated sites were examined and re-entry procedures performed 6 months after reconstructive surgery. Open flap debridement at maxillary furcations of degree II resulted in some gingival recession and probing depth reduction, but no change occurred in parameters describing probing attachment or bone levels. The addition of GTR at buccal furcations enhanced the treatment result by promoting probing attachment and bone gain and reduced the amount of soft tissue recession above what was accomplished by flap debridement alone. No such benefit of membrane therapy was observed at mesial and distal furcations.     

因重度牙周炎拔除的磨牙根分叉形态测量及根柱凹陷发生率的调查

目的 :了解因重度牙周炎拔除的磨牙根分叉形态及根柱凹陷的发生情况。方法 :对因重度牙周炎拔除的 3 0个上颌第一磨牙 ,15个上颌第二磨牙 ,3 0个下颌第一磨牙及 10个下颌第二磨牙进行测量 ,记录牙根长度(RL) ,根柱长度 (RTL) ,釉牙骨质界处的近远中径 (MDD)和颊舌径 (BLD) ,根柱凹陷的有无 ,釉牙骨质界到根柱凹陷的距离及根分叉开口下 2mm的宽度。结果 :①无论是上颌还是下颌磨牙 ,第一磨牙牙根长度及根柱长度均较第二磨牙短 ,而第一磨牙颊舌径、近远中径及根分叉开口下 2mm处宽度均较第二磨牙大 ,其中仅 4.71%的牙根分叉开口下 2mm处宽度小于 0 .75mm。②上颌磨牙根柱凹陷发生率高于下颌磨牙 ( p <0 .0 5 ) ,且 89.41%的牙至少在一个面上从根柱凹陷到釉牙骨质界的距离为零。结论 :根柱凹陷可能是造成根分叉病变的原因 ,并可能是导致牙周治疗效果欠佳的原因。     

Morphometric analysis of the furcation anatomy of mandibular molars

BACKGROUND: Successful treatment of molar furcation defects remains a challenge in clinical practice. Knowledge of anatomic factors facilitates predictable management of furcation involvement lesions. The degree of success in managing furcation involvement is inversely related to the horizontal probing depth. The depth of the horizontal component of attachment loss can vary depending on the external tooth-surface reference points used. However, the anatomical factors affecting horizontal component of attachment loss have not been previously assessed. Therefore, this study determined the bucco-lingual measurements of the cemento-enamel junction and the mesial and distal roots and at the level of root separation. METHODS: One hundred extracted permanent human mandibular first (N = 50) and second (N = 50) molars were studied. Four horizontal bucco-lingual widths were measured with calibrated calipers: 1) furcation entrance/roof (FE); 2) cemento-enamel junction level (CEJ); 3) mesial root width (MRW); and 4) distal root width (DRW). RESULTS: The mean widths at FE, CEJ, MRW, and DRW were, respectively, 5.53 +/- 0.45 mm, 8.71 +/- 0.54 mm, 8.57 +/- 0.54 mm, and 7.97 +/- 0.65 mm in the first molars and 5.61 +/- 0.65 mm, 8.40 +/- 0.65 mm, 7.95 +/- 0.88 mm, and 7.16 +/- 0.84 mm in the second molars. Analysis of variance revealed significant differences between FE and the other variables tested. The results showed that the bucco-lingual width of the furcation roof is considerably shorter than the MRW and DRW. The difference in the mean bucco-lingual dimension between FE and the other measurements occurred in all teeth evaluated and varied between 0.7 and 4.30 mm. CONCLUSIONS: Our findings demonstrate that clinical measurements of horizontal probing depth that use the external surfaces of roots as reference points overestimate the true anatomical component of furcation involvement in mandibular molars. Conversely, positive treatment outcomes in these teeth may be underestimated. This has implications not only for clinical practice but also for clinical research studies evaluating treatment outcomes.     

Periodontal changes in furcations resulting from orthodontic uprighting of mandibular molars.

Periodontal examinations were carried out preorthodontically and again 2 to 28 months after orthodontic uprighting of 20 molars (40 furcation areas) in 16 patients. Preorthodontically, patients presented with generalized periodontitis. Postorthodontically, nine of 20 buccal furcations had become more severe, one had improved, and ten remained unchanged. Lingually, nine worsened, and 11 had no change. Furcation area pocket depths increased in 35.0% of furcations, but did not change in 57.5%. Furcation root form was not associated with the degree of change. Possible mesial root extrusion was found in 60.0% of the uprighted molars. The molars showing root extrusion had furcations that increased in severity. Heavy uprighting forces contributed to extrusion, and some effect may have been due to periodontal inflammation and bone loss. Mandibular molars can be uprighted in patients with moderate periodontitis, but light intrusive forces in an inflammation-free environment are recommended.     

Radiographic parameters as prognostic indicators for healing of class II furcation defects

OBJECTIVE: To evaluate radiographic measurements for use as prognostic indicators for healing of class II furcation defects following regenerative therapy. MATERIAL AND METHODS: In 17 patients (eight females), 33 class II furcation defects (mandibular buccal (n=10) and lingual (n=12), and maxillary buccal (n=11)) were treated using the barrier membrane technique. Twenty-six furcations were treated using a bioabsorbable membrane, while a nonresorbable membrane was used to treat the remaining seven furcation defects. Clinical parameters and standardized radiographs were obtained before as well as 6 and 24 months after therapy. All radiographs were digitized and evaluated by an examiner blinded to the clinical data. The following distances were measured: cemento-enamel junction line (CEJ-line) to alveolar crest (AC) at the furcation site (AC-CEJ line), CEJ-line to the furcation fornix (Fx-CEJ line), width of the furcation at the level of the AC (FW) as well as the distance from Fx to a straight line between the AC mesial and distal of the tooth (Fx-AC line). RESULTS: Statistically significant (p<0.001) horizontal attachment gains could be observed 6 and 24 months after therapy (6 months: 1.49+/-0.85 mm; 24 months: 1.14+/-0.91 mm). However, a small but statistically significant (p=0.031) attachment loss of 0.35 mm was observed between the 6 and 24 months examination. Multilevel regression analyses identified baseline probing depth (p=0.0017) and 3 of the radiographic distances as prognostic factors: Fx-CEJ line (p=0.014), FW (p=0.0535), Fx-AC line (p=0.0827). CONCLUSION: The analysis of presurgical radiographs may yield information on the success of the regenerative therapy of buccal and lingual class II furcation defects. A long root trunk, a wide furcation entrance and an Fx coronal to the AC have negative influences on the success of therapy. Further, a deep probing depth at the furcation site at baseline increases the likelihood for more favourable horizontal attachment gain in furcations.     

Injectable simvastatin in periodontal defects and alveolar ridges: pilot studies

BACKGROUND: Topical injection of simvastatin in methylcellulose gel was shown to stimulate bone growth and inflammation over mouse calvaria and in rat mandible models. The purpose of these pilot studies was to evaluate the potential of locally injected simvastatin in human-sized periodontal defects. METHODS: Chronic periodontal defects were created bilaterally in seven 1-year-old beagle dogs: 3-walled intrabony defects distal of the mandibular second premolar and mesial of the fourth premolar and Class II furcation defects at the buccal furcation of the mandibular first molars. The edentulous space distal to the mandibular canine was left undisturbed. After 16 weeks of healing, defect sites were treated with scaling and root planing, and mandible sides were randomly selected to receive three weekly injections of 0.5 mg simvastatin in 30 microl methylcellulose gel and contralateral gel alone (n=3) or 2.0 mg simvastatin/methylcellulose gel and contralateral gel alone (n=4). Two months following drug application, block sections, including teeth and surrounding tissues, and submandibular lymph nodes were obtained for histomorphometric analysis. RESULTS: Two trends were noted in this pilot study: buccal edentulous ridge thickness was 29% greater with simvastatin, 0.5 mg, compared to gel alone (P=0.0845), and the simvastatin groups had bone-height loss in interproximal intrabony and furcation defects, but the length of new cementum in the interproximal intrabony defects was greater with simvastatin, 0.5 mg (0.35+/-0.14 mm), compared to gel alone (0.06+/-0.15 mm; P=0.069). No new cementum was found in furcations. CONCLUSIONS: Multiple injections of simvastatin are not appropriate for the treatment of intrabony or furcation defects. However, this approach shows potential to augment bone thickness in closed alveolar environments.     

Radiographic Characteristics of Furcation Involvements in Mandibular Molars as Prognostic Indicators of Healing After Nonsurgical Periodontal Therapy

BackgroundThe authors conducted a study to evaluate the radiographic characteristics of Class II mandibular furcation involvements as prognostic indicators of healing after nonsurgical periodontal therapy.MethodsTwenty-three patients with chronic periodontitis (Class II furcation involvements in mandibular molars, probing pocket depth [PPD] of 5 millimeters or greater and bleeding on probing [BOP]) were selected to receive nonsurgical periodontal treatment. The authors evaluated visible plaque index, BOP, position of the gingival margin, PPD, relative attachment level (RAL) and relative horizontal attachment level. On radiographs, the authors measured root trunk, bone attachment level in the furcation region, lesion height (Lh), furcation width at alveolar crest level inside furcation (Fw) and 2 mm apical to the fornix (Fw2), and the perpendicular distance from the horizontal line connecting mesial and distal radiographic alveolar crest to furcation fornix. They analyzed all data using linear multiple regression.ResultsSix months after treatment, the furcations showed a mean RAL gain of 1.08 mm (± 1.25 mm) and a PPD decrease of 2.74 mm (± 1.58 mm). The authors found a statistically significant influence between Fw and PPD (P = .0044), Fw2 and PPD (P = .0014), Lh and PPD (P = .0241), and Fw2 and RAL (P = .0037).ConclusionsWithin the limitations of this study, the results suggest that Fw, Fw2 and Lh may influence the response of Class II mandibular furcations to nonsurgical periodontal therapy and may serve as prognostic indicators for this therapy. Thus, narrower and shorter root furcations would be expected to have better outcomes.     

Biometric study of furcation area of first maxillary molars

The present investigation was designed to study the distance from the 3 bifurcation entrances to their opposite roots, and also the virtual center of the trifurcation (TC), which is equidistant from each bifurcation entrance, of maxillary molars. Thirty-five teeth devoid of any surface damage or fused roots were selected. Roots were included in acrylic resin and cross-sectioned at the cementoenamel junction to the apex using a rotary diamond blade and 0.45-mm slices were obtained. A profile projector apparatus was used to obtain the coordinated points on a Cartesian plane, which allowed the calculation of all distances present using analytic geometric formulas. Based on statistical analysis (comparison by Kruskal-Wallis ANOVA test, p<0.05), the following results were obtained: 1) mean distance from the buccal furcation reaching the palatal root was 6.72 +/- 0.99 mm (range 4.73-8.67 mm); 2) mean distance from the mesial and distal furcations to the distal and mesial roots were 5.42 +/- 0.83 mm (range 3.78-7.07 mm) and 5.90 +/- 0.87 mm (range 4.18-7.59 mm), respectively. All means were determined up to the point of 1.40 mm from each bifurcation opening; 3) mean distance of TC was 4.26 +/- 0.42 mm (range 3.44-5.08 mm) for all levels.     

Linear variation of the root surface area of the maxillary first molar

The variation of root surface area (RSA) in 1-mm increments from the cementoenamel junction (CEJ) to the apex was determined for the maxillary first molar. Twenty extracted maxillary first molars were cross sectioned every millimeter, and each section was photographed, projected and measured with a calibrated opisometer. The RSA and percentage of RSA were calculated for each 1-mm section. The location of furcation entrances, root separations and roofs of the furcations was also determined. Analysis of the mean measurements demonstrated that (1) the largest per cent of RSAs were found in the furcation area; (2) the mean distance from the CEJ was 3.6 mm for the mesial furcation entrance, 4.2 mm for the facial furcation entrance and 4.8 mm for the distal furcation entrance; (3) the mean distance from the CEJ to the point at which the roots separate from the root trunk was 5.0 mm for the mesiobuccal root and 5.5 mm for the distobuccal root; (4) in 11 of the 20 teeth the roof of the furcation was coronal to all root separations, forming a concave dome between roots. According to the individual and mean measurements, horizontal attachment loss of 6.0 mm or greater would have resulted in Grade III furcation involvement in all the teeth studied.     

The reliability of furcation measurements

Abstract. The furcation involvement of 100 molars in 25 patients suffering from moderate to advanced periodontitis was investigated. Presurgically, the horizontal probing attachment level (PAL-H) within the furcations was assessed 2 × within 14 days. To determine the measurement error of PAL-H, the standard deviation of single measurements was calculated. The measurements were repeated intrasurgically and compared with presurgical assessments of furcation degrees. The overall standard deviation of single measurements was 0.739 mm. For buccal, lingual, mesiolingual and distolingual furcations, the standard deviations were 0.602 mm, 0.559 mm, 0.759 mm, 1.099 mm, respectively; measurement error was less in buccal and lingual furcations than in distolingual furcations ( p <0.001). The agreement of replicate measurements of furcation degrees was excellent for buccal, lingual and mesiolingual furcations (weighted κ– coefficients between 0.776 and 0.944), but only moderate for distolingual furcations (κ_w= 0.706). Multiple linear regression analysis revealed significant influence of furcation depth, width and furcation location on differences of PAL-H ( p <0.05). There was no significant difference between furcation degree as assessed presurgically and intra-surgically.     

Correlation of Root Dentin Thickness and Length of Roots in Mesial Roots of Mandibular Molars

Introduction

The purpose of this study was to analyze the relation of tooth length and distal wall thickness of mesial roots in mandibular molars at different locations (ie, 2 mm below the furcation and at the junction between the middle and apical third).

Methods

Forty-five mandibular first molars were taken, and the length of each tooth was measured. Then, specimens were divided into three groups according to their length: group I–long (24.2 mm ± 1.8), group II–medium (21 mm ± 1.5) and group III–short (16.8 mm ± 1.8). mesial root of each marked at two levels - at 2 mm below the furcation as well as at junction of apical and middle third of roots. The minimum thickness of the distal root dentine associated with the buccal and lingual canals of the mesial roots was measured, The distance between the buccal and lingual canals and the depth of concavity in the distal surface of the mesial roots were also measured.

Results

Statistical analysis was performed by using analysis of variance and the Student-Newman-Keuls test. The minimum thickness of the distal wall of the mesiobuccal canal was significantly different (P < .001) between groups 1 (long) and 3 (short).

Conclusions

Distal wall thickness of the mesiobuccal root and distal concavity of the mesial root of mandibular first molars were found to be thinner in longer teeth compared with shorter teeth.     

Topographic study of root trunk type on Chinese molars with Class III furcation involvements: molar type and furcation site

This study investigated the relationship between root trunk length and prognosis for molars with furcation involvement. Molars with furcation involvement were obtained from 169 patients affected with periodontitis. The test group consisted of 174 hopeless molars screened from a total of 441 molars with Class III involvement; the remaining 267 molars formed the control group. Both arches showed a significantly higher missing rate for teeth with a long root trunk length (type C) in second molars (41.3% and 32.4% in the maxilla and mandible, respectively), with a high degree of Class III furcation involvement for the test group (extracted hopeless or poor prognosis), compared to first molars (9.9% and 0.9% in the maxilla and mandible, respectively). Both arches had a significantly higher prevalence of long root trunk lengths in the second molars compared to first molars, irrespective of furcation site. Although first molars had an early and higher prevalence of Class III furcation involvement than second molars, the latter reached a significantly higher missing rate. Molars with longer root trunk lengths had a higher risk for poor prognosis than shorter root trunks when teeth were affected by Class III furcation involvement. For extracted furcation-involved maxillary second molars that failed to respond to periodontal therapy, long root trunk length (C) accounted for the greatest prevalence at the mesial furcation site (41.8%), followed by the distal (33.0%) and buccal sites (25.2%); the greatest prevalence of root trunk length C was found at the lingual (47.9%) and buccal furcation sites (45.1%) of mandibular second molars. When a molar with root trunk type C has a Class III involvement, the prognosis is poor; for the disease to reach that level, greater amounts of attachment must be destroyed.     

Topographical characteristics of root trunk length related to guided tissue regeneration.

Thirty-seven molars with 94 furcations were selected for a topographical study of root trunks to clarify the possible factors which may affect the clinical application of guided tissue regeneration technique. A pre-determined plane was marked on the root trunk of each tooth 1 or 2 mm below the cemento-enamel junction (CEJ). The plane followed the presumed position of the occlusal border of the Teflon membrane. Cross sectioning of the root was then performed following the plane, and the width of the gap between the membrane and root surface was measured with the aid of a stereomicroscope. The results revealed, within the limited samples of this study, 94% of the furcations possessed variant depth of developmental concavities on the root trunks. These superficial irregularities at the entrances of furcations may prevent complete adaptation of the coronal microstructure of the Teflon membrane along their root surfaces. The width of the gaps between root surfaces and membranes ranged from 0.000 mm to 2.250 mm for all tooth samples. The study implied that the subgingival application of guided tissue membranes 1 to 2 mm below CEJ cannot ensure complete adaptation of furcation defects with their coronal microstructures in the majority of molars.     

Effects of furcation involvements on periodontal status and healing in adjacent proximal sites

BACKGROUND: In a recent study it was found that following non-surgical treatment, probing depth (PD) reduction in proximal sites is significantly less in the presence of a vertical destruction in the adjacent site of the neighboring tooth. The present investigation was undertaken to study whether the presence of a proximal furcation involvement also influences the periodontal conditions in the adjacent site of the neighboring tooth. METHODS: The investigation was conducted as a retrospective study on a consecutive referral population based on full-mouth oral radiographic examinations and PD and plaque score registrations. The statistical analyses were performed on a final sample of 136 patients, with 153 (periodontal status) and 123 (periodontal healing) second maxillary premolars with an adjacent first maxillary molar. RESULTS: Baseline pockets were significantly deeper, relative radiographic attachment levels significantly reduced, and periodontal PD significantly less reduced after non-surgical treatment in the distal sites of second maxillary premolars adjacent to first maxillary molars with a mesial furcation involvement of degree > or = 2, compared to distal sites adjacent to first maxillary molars with a mesial furcation involvement of degree < or = 1. CONCLUSIONS: Periodontal status and healing after non-surgical treatment in proximal sites are negatively influenced by the presence of a deep furcation involvement in the adjacent site in the same proximal space. The presence of a deep proximal furcation involvement should consequently be considered a risk factor for the adjacent site of the neighboring tooth.     

Cervical enamel projections as an etiologic factor in furcation involvement.

Two thousand molars in 200 East Indian skulls were examined for the occurrence, location, and grade of cervical enamel projections. The relationship between the enamel projections and furcation involvements was studied. Several findings resulted. The incidence of cervical enamel projections in molars was 32.6%. The incidence of cervical enamel projections varied between molars. The mandibular second molars showed the highest incidence of enamel projections (51.0%), followed by the maxillary second molars (45.6%). The lowest incidence was seen in the maxillary first molars (13.6%). Grade 1 enamel projections were the most frequently encountered. Cervical enamel projections occurred most frequently on the buccal surfaces of teeth. There was a positive, statistically significant relationship between tooth surfaces with grade 2 and 3 enamel projections and periodontally involved furcations. However, no etiologic relationship was found between grade 1 projections and furcation involvements. There seems to be a physiologic relationship between bone and enamel projections. The alveolar crest has a tendency to follow the outline of the enamel projection, and a channel much wider than a normal periodontal membrane space accommodates the enamel projection as it extends toward the furcation. The results indicate that when cervical enamel projections are severe enough to approach or enter the furcation area (grades 2 and 3), they may be an etiologic factor in the breakdown of these furcations.