Root trunk height as a risk factor for periodontal furcation involvement in maxillary first molars: an in vitro study

The aim of this study was to correlate the root trunk height from the furcation openings on the buccal, mesial and distal surfaces to the cemento-enamel junction in upper first permanent molars in human beings with risk for periodontal disease progression. One hundred extracted maxillary first molars were used. Reference points and demarcations were determined from the entrance of the buccal (F1), mesial (F2) and distal (F3) furcations to the cemento-enamel junction in millimeters. The mean distances found were 3.50 mm, 4.44 mm and 4.26 mm for the buccal, mesial and distal furcations, respectively, in relation to the cemento-enamel junction. The statistical analyses were Student's t-test and Chi-square (X2). With periodontal disease progression, the buccal furcation presents a greater compromising risk due to its proximity to the cemento-enamel junction, while the mesial furcation is the most distant, comprising a lesser risk.     

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.     

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.     

A long term study of root retention in the treatment of maxillary molars with furcation involvement.

A study was done to evaluate long-term results of treating 387 maxillary molars with furcation involvement in 100 patients with chronic destructive periodontal disease. Results showed a favorable long term functional survival rate of 341 teeth (88%) 5 to 24 years after treatment, despite the fact that many teeth had at least one root with 50% or less of bone support before treatment. Of the 46 teeth (12%) that were ultimately extracted, 25 were present for a significant length of time (6 to 18 years) before extraction. The radiographs of 292 teeth (75%) showed no significant change in bone support 5 to 24 years after treatement, while those of 8 teeth (2%) suggested improvement. There was perceptible increase in bone loss in 41 teeth (11%). Forty-six (12 %) were extracted. All periodontally involved teeth in each patient of the study were treated. Specific treatment for maxillary molars with furaction involvement included soft tissue therapy; coronal reshaping, if indicated; and instruction in home care. Considerable emphasis was placed on improving occlusal function. In no case was root amputation, hemisection, osseous surgery, or reshaping of the cervical area of the tooth done. A total of 366 (94%) of the teeth did not have endodontic therapy before, during, or after the study. Therefore endodontic therapy was not a significant factor in retention of the 341 teeth.     

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.     

上颌第一恒磨牙80颗牙体解剖的离体研究

目的 :了解上颌第一恒磨牙牙体解剖基础知识。方法 :肉眼观察近颊根外形 ,牙合面磨耗程度 ,髓室底形态 ,根尖孔数目及类型 ;游标卡尺测量各项长度指标及根尖孔到牙根顶点的距离 ;透明牙标本法观察根管系统。结果 :上颌第一恒磨牙近颊根Ⅲ型根尖孔 2 6.9% ;双根管率为 5 6.2 5 % ,三根管率为 7.5 %。结论 :上颌第一恒磨牙近颊根存在着较高的多根管率 ( 63 .75 % ) ,应该引起临床医生的高度重视     

Orthodontic treatment of impacted first permanent maxillary molars

The etiology and treatment of impacted first maxillary molars has been reported. Appliance selection criteria, as well as treatment planning considerations have also been discussed. Although impacted first maxillary molars can be treated with either fixed or removable orthodontic appliances, the selection of the appliance should be based on the overall severity of the malocclusion.     

C-shaped root canal configuration in maxillary first molars

AIM: This clinical report presents the endodontic treatment of two maxillary first molars and the anatomical study of two additional maxillary first molars with a C-shaped distally located root canal system. This configuration is not a common finding. SUMMARY: According to the endodontic literature, the C-shaped root canal is most frequently seen in the mandibular second molar. The occurrence of C-shapes in maxillary first molars, however, has only been described in a limited number of case reports. We observed this configuration in two out of 2175 root-filled maxillary first molars treated at the Department of Endodontology, Ghent University Hospital, during the last 10 years. In order to study and visualize this particular aberration, cross-sections in two additional two-rooted maxillary first molars were made. From these cross sections it can be concluded that the C-shaped canal configuration is the result of a fusion of the distobuccal and the palatal roots.     

Guided tissue regeneration in the treatment of degree III furcation defects in maxillary molars

Abstract 11 subjects with generalized periodontitis and advanced lesions in the maxillary molar regions, including bilateral mesial-distal, but not buccal, degree III furcation defects in the 1st and/or 2nd molars, were recruited for the present clinical trial. The patients were given oral hygiene instruction and full-mouth scaling and root planing. A re-examination was performed after 3 months of healing, after which the furcation involved molars were randomly selected for a GTR or conservative treatment modality. An informed consent form was signed by each participating patient. The GTR procedure invoived the elevation of mucoperiostal flaps, root surface debridement, and the placement of an e-PFTE membrane at the 2 entrances of the furcation defect. The flaps were repositioned and secured. The contralateral molar was treated in an identical manner but without the placement of the teflon membrane. The patients received amoxicillin (I g×2/day for 8 days), were placed on chlorhexidine mouth rinsing and were recalled for prophylaxis 1 × every 2 weeks. The teflon membranes were removed at a 2nd stage procedure after 6 weeks. All subjects were re-examined 6 months after the regenerative procedure, and in addition, all sites were evaluated following a reentry procedure. The final examination and measurements made during the reentry procedure documented that, although some reduction in probing pocket depth and some gain in probing attachment had occurred at both test and controi sites, none of the furcation defects had closed, but retained the characteristics of a degree-Ill furcation involvement.     

Bilateral C shape configuration in maxillary first molars

The C-shaped canal is unusual. It is most frequently reported in mandibular molars. A case of bilateral C-shaped canals in maxillary molars is reported here.     

上颌第一磨牙根管系统的研究

目的 观察上颌第一磨牙的根管系统。方法 制备50个上颌第一磨牙透明牙标本,显露根管系统的空间构型,在体视显微镜下观察并记录根管系统的形态,结合应用加以统计。结果 ①上颌第一磨牙近中颊根单根管率为66%,其中Ⅰ型占38%,双根管率为34%,远中颊根Ⅰ型占74%,腭根Ⅰ型占94%。②根管侧支、根尖分歧、根尖分叉多见于近颊根,在近颊根的发生率为40%, 远颊根的发生率为24%,腭根的发生率为6%,发生部位多见于根尖1/3。结论 上颌第一磨牙近颊根的根管系统最为复杂,根管变异较远颊根多,腭根变异最少。     

A simplified method for distalization of maxillary first molars

This article describes a system on how to select the proper type of appliance to distalize maxillary first molars, as well as a step by step sequence of treatment to achieve an ideal occlusion.     

Furcation topography of the maxillary and mandibular first molars

The objective of the present study was to describe the topography of the furcation area of the maxillary and mandibular first molars. By using a photogrammetric method, the furcation areas of extracted teeth were plotted to obtain 3-dimensional contour maps. By comparing the individual 10 drawings of the maxillary and mandibular first molars, respectively, some morphological characteristics of the furcation areas could be described. Accordingly, the study showed the complexity of the furcation areas with presence of a number of small ridges, peaks and pits forming a mixture of convexities and concavities.     

Retention of maxillary molars with Class III furcation involvement utilizing glass-ionomer: two case reports

Advanced furcation invasion has long been a treatment dilemma for the clinician. The present two case reports used a glass ionomer restorative material as a barrier in the treatment of maxillary Class III furcation defects. One year follow-up results showed a reduction in tooth mobility and probing depths and no bleeding on probing with the use of the glass ionomer. These case reports offer another option in the treatment of a seemingly hopeless periodontally involved maxillary molar.     

Concurrent relationship between additional canals of mandibular first molars and maxillary first molars using cone-beam computed tomography

Objective

To investigate the bilateral concurrence and relationships between distolingual (DL) roots and DL canals of the mandibular first molars and second mesiobuccal (MB2) canals of the maxillary first molars using cone-beam computed tomography (CBCT).

Methods

A total of 150 CBCT images showing all mandibular and maxillary first molars were retrospectively investigated in a South Korean subpopulation. The patient age, sex, positions of first molars, and presence of roots and canals were assessed. The frequency, bilateral concurrence of DL roots, DL canals, and MB2 canals, and concurrent relationship of DL roots or DL canals with MB2 canals were investigated. Data were analyzed using Fisher’s exact test and odds ratios from binary logistic regression.

Results

The prevalences of DL roots, DL canals, and MB2 canals were 24.7, 42.7, and 56.0 %, respectively, and showed significant bilateral concurrence. A concurrent relationship between DL roots and MB2 canals was not demonstrated, whereas the presence of a DL canal was significantly correlated with the presence of an MB2 canal on the same side.

Conclusions

The presence of a DL root of the mandibular first molar, a strong ethnic characteristic, could not predict the presence of an MB2 canal of the maxillary first molar. The correlation between DL canals and MB2 canals on the same side and the significant bilateral concurrence, whether present or absent, of DL roots, DL canals, and MB2 canals can aid clinicians in the prediction of additional canals in the first molars.