Furcation depth and interroot separation dimensions for 5 different tooth types

The purpose of this study was to document mean, standard deviation, and range of furcation depth and Interroot separation dimensions of 5 multirooted tooth types. A total of 412 extracted teeth were examined and classified as: maxillary first molar, maxillary second molar, maxillary first premolar, mandibular first molar, and mandibular second molar. The furcation depth was measured at the level of the furcation dome and 3 and 5 mm apical to the dome. Interroot separation was measured 3 and 5 mm apical to the furcation dome. Mean furcation depth at the dome was 7.48 mm buccally and 6.67 mm mesiodistally for maxillary first molars; 6.69 mm buccally and 5.94 mm mesiodistally for maxillary second molars; 3.54 mm mesiodistally for maxillary first premolars; 7.96 mm buccolingually for mandibular first molars; and 7.46 mm buccolingually for mandibular second molars. Interroot separation dimensions 3 mm apical to the dome were: 2.58 mm buccally, 4.17 mm mesially, and 4.48 mm distally for maxillary first molars; 1.92 mm buccally, 3.89 mm mesially, and 4.04 mm distally for maxillary second molars; 2.47 mm mesially and 2.58 mm distally for maxillary first premolars; 3.15 mm buccally and 2.95 mm lingually for mandibular first molars; and 2.54 mm buccally and 2.75 mm lingually for mandibular second molars.     

A scanning electron microscopic investigation of accessory foramina in the furcation and pulp chamber floor of molar teeth

Observations of the pulp chamber floor and furcation surface of human maxillary and mandibular first and second molars were made with the scanning electron microscopic to determine the incidence, size, and location of patent accessory foramina. Accessory foramina on both the pulp chamber floor and the furcation surface were found in 36% of maxillary first molars, 12% of maxillary second molars, 32% of mandibular first molars, and 24% of mandibular second molars. Mandibular teeth had a higher incidence (56%) of foramina involving both the pulp chamber floor and furcation surface than did the maxillary teeth (48%).     

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。     

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.     

Morphological measurements of anatomic landmarks in human maxillary and mandibular molar pulp chambers

The aim of this in vitro study was to measure critical morphology of molar pulp chambers. One hundred random human maxillary and mandibular molars (200 teeth in total) were used. Each molar was radiographed mesiodistally on a millimeter grid. Using a stereomicroscope, the measurements were read to the nearest 0.5 mm. Results were as follows (mean, mm): pulp chamber floor to furcation, maxillary = 3.05 +/- 0.79, mandibular = 2.96 +/- 0.78; pulp chamber ceiling to furcation, maxillary = 4.91 +/- 1.06, mandibular = 4.55 +/- 0.91; buccal cusp to furcation, maxillary = 11.15 +/- 1.21, mandibular = 10.90 +/- 1.21; buccal cusp to pulp chamber floor, maxillary = 8.08 +/- 0.88, mandibular = 7.95 +/- 0.79; buccal cusp to pulp chamber ceiling, maxillary = 6.24 +/- 0.88, mandibular = 6.36 +/- 0.93; and pulp chamber height, maxillary = 1.88 +/- 0.69, mandibular = 1.57 +/- 0.68. The pulp chamber ceiling was at the level of the cementoenamel junction in maxillary, 98%, and mandibular, 97% of the specimens. The measurements showing the lowest percentage variance were buccal cusp to furcation (approximately 11%) and buccal cusp to pulp chamber ceiling (approximately 14%). The measurements were similar for both maxillary and mandibular molars.     

Incidence of patent furcal accessory canals in permanent molars of a Turkish population

Aim To determine the incidence of patent furcal accessory canals in permanent molars of a Turkish population. Methodology Two‐hundred extracted teeth consisting of 50 maxillary first molars, 50 maxillary second molars, 50 mandibular first molars and 50 mandibular second molars from Turkish patients attending the Oral Surgery Department of the Faculty of Dentistry, ?stanbul University, ?stanbul, Turkey, were included in the study. After preparation of access cavities and removal of pulp tissue, the teeth were stored in 5.25% sodium hypochlorite for 1 h. Following double‐sealing of the access cavities, all tooth surfaces except the furcation regions were covered with nail varnish. The teeth were stored in 0.5% basic fuchsin for 1 week. The teeth were sectioned at the cemento‐enamel junction and the presence of patent furcal canals was established by examining the pulp chamber floor with a stereomicroscope (10×) to determine staining. Results Patent furcal accessory canals were detected in 24% of maxillary first molars, 16% of maxillary second molars, 24% of mandibular first molars, and 20% of mandibular second molars. No statistically significant differences were found between the tooth types. Conclusions In a Turkish population, the incidence of patent furcal accessory canals on the pulp chamber floor of maxillary and mandibular first and second molars ranged between 16 and 24%.     

Molar root furcation: morphometric and morphologic analysis

The objective of the present study was a morphometric and morphologic analysis of maxillary and mandibular first and second molars using three different techniques. Measurements of 207 maxillary molars (105 first and 102 second molars) and 207 mandibular molars (110 first and 97 second molars) were measured; root length, radicular trunk length (RTL), mesiodistal and buccolingual diameters (BLD) at the cementoenamel junction, inter-radicular angle (IRA) width, and furcal roof area (FRA) were recorded. No significant statistical correlations were found for most of these measurements, the only exception being the relationship between IRA/FRA, IRA/BLD in maxillary molars, and IRA/RTL in the maxillary first molar. Morphologic examination was carried out by stereo microscopy, light microscopy of undecalcified sections, and scanning electron microscopy. All of these techniques showed the complexity of the furcation area with a large number of anatomic irregularities and plaque-retentive structures that could hamper adequate cleaning during periodontal treatment.     

Accessibility of an ultrasonic furcation tip to furcation areas of mandibular first and second molars

The purpose of this study was to compare an ultrasonic furcation tip with an ultrasonic conventional tip and a hand scaler on accessibility to furcation areas of mandibular first and second molars. The study was conducted on 360 artificial molars that were replicated from 30 mandibular first molars and 30 second molars with silicone impression material and resin. The furcation areas of each molar were coated with red nail colour for artificial calculus. The root areas from the cement-enamel junction apically were covered with silicone rubber simulating gingival tissue. Then the models were instrumented on the buccal or lingual aspects by an experienced operator with each of the following instruments: an ultrasonic furcation tip, an ultrasonic conventional tip and a hand scaler. After instrumentation the percentage of the furcation area with residual artificial calculus was assessed using a computerised imaging system. Results showed that when the horizontal pocket depth was less than 2mm, all three instruments showed good accessibility. When the horizontal pocket depth was more than 2mm, the ultrasonic conventional tip and the hand scaler showed less removal of artificial calculus than the ultrasonic furcation tip (P < 0.01). Efficiency of the ultrasonic furcation tip was fairly satisfactory for the horizontal pocket up to the ridge of the furcation roof.     

Relationship between periodontal furcation involvement and molar cervical enamel projections

A total of 78 individuals ages 21 to 61 years with periodontal furcation involvement was examined for the presence of cervical enamel projections on the buccal surfaces of molar teeth. The furcal defects and cervical enamel projections (CEPs) of molars were diagnosed by probing, periapical roentgenographs, flap operation and inspection. Plaque index (PlI) and gingival index (GI) were recorded for the buccal and lingual surfaces of molars examined. The percentage of CEPs in the 78 individuals examined was 67.9%. The prevalence of CEPs in all molars examined was 45.2%. The prevalence of CEPs in molars with and without furcal involvements were 82.5% and 17.5%, respectively. The frequency of CEP in molars occurred in the following order: mandibular first molars, maxillary first molars, mandibular second molars and maxillary second molars. Statistical analyses (Chi-square test) revealed a significant difference between periodontal furcation involvements and the presence of CEPs. Results of this study also indicated that the furcal involvements with CEPs were associated with poor oral hygiene as measured by GI and PlI.     

In vitro effectiveness of a newly-designed ultrasonic scaler tip for furcation areas

This study was undertaken to perform an in vitro comparison of the accessibility and effectiveness of a newly-designed furcation tip for an ultrasonic system with conventional curets and ultrasonic scalers. The new furcation tip was spiral in shape with a spherical end. The study was conducted on three groups of 40 teeth, each comprising 20 maxillary and 20 mandibular molars. The furcation of each tooth was colored by black felt-tipped marker, after which the teeth were fixed into artificial jaw models. Each group was then instrumented by either the newly-designed furcation tip, a straight type ultrasonic scaler tip, or a Gracey curet. The teeth were photographed by a stereomicroscope from the dome surface of furcation, and the percentage of remaining colored area was calculated for each tooth. Replica models were also made and examined with scanning electron microscopy (SEM). The mean percentage of the remaining colored areas for each instrument was, for the maxillary molars and mandibular molars respectively, 15.1% and 16.7% with the newly-designed tip; 50.3% and 44.1% with the straight type ultrasonic scaler; and 61.1% and 39.5% with the Gracey curets. The newly-designed tip thus showed high levels of effectiveness and accessibility for furcation debridement. Although the SEM photographs showed that each instrument had affected the furcation surfaces in various degrees, the teeth instrumented by the newly-designed tip maintained relatively smoother surfaces. It was concluded that the newly-designed furcation tip was more effective than the straight type ultrasonic scaler or the Gracey curet in the debridement of furcation in vitro.     

A preliminary in vitro study of the incidence and position of the root canal isthmus in maxillary and mandibular first molars

AIM: To investigate in vitro the incidence and position of the root canal isthmus in extracted mesiobuccal roots of maxillary and mesial roots of mandibular first molars. METHODOLOGY: Fifty maxillary and 50 mandibular molars were included in the study. The mesiobuccal roots of maxillary molars and the mesial roots of mandibular molars were sectioned from their crowns in the furcation region and embedded in clear resin. Transverse serial 1-mm-thick sections from the apical 6 mm were prepared. The apical side of each section was stained with India ink and observed through a light microscope. The sample images were saved to disk using a digital camera and the root canals in terms of the number present and the incidence and classification of isthmuses. RESULTS: In the mesiobuccal root of the maxillary first molars, 70% had one canal, whereas 29.5% had two canals. In the mesial root of mandibular molars, 41% had one canal, whereas 59% had two canals. In some sections, more than two canals were found close to the apical foramen. The isthmus incidence was greatest 3-5 mm from the apex. In teeth having two canals, a complete or partial isthmus was frequently observed in the sections between 3 and 4 mm from the apex. Of the isthmuses present, 22% were complete and 37% partial in mandibular molars and 17.3% were complete and 11.7% partial in maxillary molars. CONCLUSIONS: The incidence of isthmus in the mesiobuccal root of the maxillary first molars and in the mesial root of the mandibular first molars was high, particularly in sections 3-5 mm from the apex. Cleaning the isthmus is a major challenge during root canal treatment.     

Cervical enamel projections in Chinese first permanent molars.

Cervical enamel projections in relation to molar furcations may act as predisposing factors in periodontal attachment loss. Limited data are available documenting these features in Chinese teeth. The purpose of this study was to determine the prevalence and distribution in a sample of first permanent molars from Hong Kong Chinese. Three hundred and sixty-two extracted first molars (194 maxillary, 168 mandibular) were selected from the Prince Philip Dental Hospital tooth collection and examined using a dissection microscope for identification and classification. Cervical enamel projections were identified in 59 per cent of maxillary and 79 per cent of mandibular first molars. Buccal aspects were more frequently involved. Forty-nine per cent were Grade III (extending to the furcation area); over one-half were particularly slender while 18 per cent were discontinuous. A modification to the classification system is proposed in order to delineate these features in future studies.     

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.     

Scanning electron microscopic investigation of incidence, location, and size of accessory foramina in primary and permanent molars.

OBJECTIVE: The purpose of this study was to determine and compare the incidence, location, and size of accessory foramina in the furcation region of permanent and primary molars. METHOD AND MATERIALS: A random sample of 100 extracted human permanent maxillary and mandibular first and second molars (25 teeth of each type) and a random sample of 100 extracted human primary maxillary and mandibular molars (50 teeth of each type) were used. The crowns and roots of each tooth were removed at a point 1.5 mm apical to the external furcation region, and a second cut was made at a point 1 mm apical to the cementoenamel junction. The specimens were examined using scanning electron microscopy at magnifications ranging from x 10 to x 1,250. The incidence, location, and size of accessory foramina were documented and statistically analyzed. RESULTS: Of the 100 permanent molars examined, 79% had accessory foramina with diameters ranging from 10 microm to 200 microm. Accessory foramina were present in 94% of the primary molars, with diameters varying from 10 microm to 360 microm. The incidence of accessory foramina was significantly higher in primary than in permanent molars. CONCLUSION: The presence of accessory foramina with large diameters may imply that an inflammatory process can spread from pulpal to periodontal tissues and vice versa.     

Morphological measurements of anatomic landmarks in pulp chambers of human maxillary furcated bicuspids

The aim of this in vitro study was to measure key morphological features of pulp chambers from furcated maxillary bicuspid teeth. There were 107 random human maxillary bicuspid teeth used. Each bicuspid was radiographed using the Trophy RVG digital imaging system and a Belmont Acuray X-ray at 70 kVp. Measurements were made using the Digipan measuring mode of the Trophy system. Results were mean (mm): pulp chamber floor to furcation: 1.85 +/- 0.85; pulp chamber ceiling to furcation: 4.61 +/- 1.04; cusp to furcation: 11.55 +/- 1.12; cusp to pulp chamber ceiling: 6.94 +/- 0.70; pulp chamber height: 2.76 +/- 0.97. The measurements showing the lowest percentage variance were: cusp to furcation (9.70%) and cusp to pulp chamber ceiling (10.09%). The only measurement that was statistically the same across maxillary molars, mandibular molars and bicuspids was measurement "B," pulp chamber ceiling to furcation. The critical distance from cusp tip to pulp chamber ceiling in bicuspids was approximately 7.00 mm.     

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.     

Acquisition of Anatomic Parameters Concerning Molar Pulp Chamber Landmarks Using Cone-beam Computed Tomography

Introduction

Cone-beam computed tomographic (CBCT) imaging is a valuable tool for endodontic therapy. The aim of this study was to verify whether clinical use of CBCT imaging can accurately acquire parameters concerning molar pulp chamber landmarks, which are important data to help start a successful access cavity and avoid iatrogenic furcation perforations.

Methods

Seventy CBCT images were used to measure 118 maxillary and 104 mandibular molars. The following vertical distances were measured: from the cusp tip/central fossa to the pulp chamber floor, to the pulp chamber ceiling, and to furcation; from the pulp chamber ceiling to furcation; from the pulp chamber floor to furcation; and the pulp chamber height. Measurements were read to the nearest 0.05 mm.

Results

The measurements were as follows: the pulp chamber floor to furcation (maxillary molar: 1.97 ± 0.58 [mean ± standard deviation, mm], mandibular molar: 2.24 ± 0.47), the pulp chamber ceiling to furcation (maxillary molar: 4.09 ± 0.68, mandibular molar: 3.78 ± 0.70), the central fossa to furcation (maxillary molar: 8.78 ± 0.79, mandibular molar: 8.53 ± 0.65), the central fossa to the pulp chamber floor (maxillary molar: 6.81 ± 0.83, mandibular molar: 6.29 ± 0.65), the central fossa to the pulp chamber ceiling (maxillary molar: 4.69 ± 0.59, mandibular molar: 4.75 ± 0.56); and pulp chamber height (maxillary molar: 2.12 ± 0.81, mandibular molar: 1.53 ± 0.68). Measurements showing the least standard deviation were the central fossa to furcation and the central fossa to the pulp chamber floor.

Conclusions

CBCT imaging may be used for precise clinical acquisition of the pulp chamber landmark measurements for molars thereby facilitating successful access cavity.     

Histological study of furcation perforations treated with tricalcium phosphate, hydroxylapatite, amalgam, and Life

One-hundred twenty experimental furcation perforations were created in the mandibular and maxillary premolars and molars of six rhesus monkeys. Tricalcium phosphate, hydroxylapatite, amalgam, and Life were used to repair the furcation perforations. The animals were sacrificed at the intervals of 2, 4, and 6 months after the experiment. Histological evaluation revealed lack of complete healing of furcation perforations repaired with any materials. Epithelium was present in the furcation perforations in both experimental and positive control groups. No hard tissue formation was observed in this study. Inflammation in the furcation area may be due to inadequate sealing ability of the repair materials.     

Root trunk dimensions of 5 different tooth types.

The primary purpose of this study was to document mean, standard deviation, and range of root trunk dimensions of multirooted tooth types. A total of 412 extracted teeth were examined and classified as: maxillary first molars, maxillary second molars, maxillary first premolars, mandibular first molars, and mandibular second molars. The distance from the cementoenamel junction (CEJ) to the root groove and from the CEJ to the root division was measured. Mean CEJ to root groove distances ranged from 1.35 to 1.65 mm for maxillary first molars, from 1.49 to 1.89 mm for maxillary second molars, from 1.71 to 1.73 mm for maxillary first premolars, from 1.16 to 1.22 mm for mandibular first molars, and from 1.53 to 1.76 mm for mandibular second molars.