Root surface measurements of the mandibular first molar

Furcation area and root proximity of molars as a risk indicator of periodontitis: a cone‑beam computed tomography-based study

OBJECTIVES

This study assessed the root proximity in molars and the furcation area (FA) in the first root separation point (RSP) using cone‑beam computed tomography (CBCT) and evaluated the association between the furcation area of molars and periodontal status of the patients.

METHODS

A total of 264 molar teeth in 66 participants were included in the study. The control group consisted of 110 molar teeth of participants, and 154 molar teeth were included in periodontitis group, which consisted of only stage II and III periodontitis patients. FA, RSP, and root proximities were measured in axial slices, and bone resorption rates were measured in sagittal slices.

RESULTS

Both maxillary and mandibular molar groups had significantly less FA in periodontitis group than in controls (p < 0.005), and there were significant relationships between the degree of bone resorption in molars and FA and furcation grades (p < 0.001). According to regression analysis, the risk of periodontitis increased by 1.011 times as total FA decreased (p < 0.001), and periodontitis risk of maxillary molar was 1.693 times higher than mandibular molars but not found to be statistically significant (p = 0.152). When assessing the root proximity between molar teeth, maxillary molars showed significantly higher root proximity in CEJs than mandibular molars in both periodontitis and control groups (p < 0.05).

CONCLUSIONS

The results indicate that the association between FA and the degree of bone resorption and root proximity of maxillary molars might be considered as a risk indicator for bone resorption in molars and might play a role during disease progression.

Diagnosis and Management of Furcation Lesions in Dogs - A Review

The furcation is the anatomic area where the roots divide on a multirooted tooth. Periodontal disease causing alveolar bone loss can lead to furcation lesions of various stages. Once furcation involvement has occurred, the area can be more difficult to clean or treat due to the complex anatomy and morphology of furcations. Teeth with short root trunks, longer tooth roots, and roots with wide furcation entrance areas/degrees of separation and wide root divergence are considered better candidates for long term maintenance. Dog teeth possess many of these advantageous anatomic features compared to human teeth. Treatment options for teeth with furcation lesions include: closed debridement, open debridement, furcation plasty, tunneling, partial tooth or root resection, root separation (hemisection or trisection), regenerative therapies, or exodontia. There are many factors to consider in determining treatment options. The favorable and unfavorable characteristics for maintenance of teeth with furcation lesions are summarized. Home care and ongoing professional care are important aspects of periodontal disease control for any patient. Studies of systemic and local antibiotic therapies in human patients have not demonstrated reduction of furcation stages, and probiotic effects at furcation sites have not been specifically examined. Human review studies show that most molar teeth once deemed "hopeless" due to stage 3 furcation lesions can be maintained for at least 5 to 15 years with supportive periodontal therapy. Similar long term studies in dogs are needed to improve the evidence-based management of canine patients with furcation lesions.

Inter radicular bone dimensions in primary stability of immediate molar implants - A cone beam computed tomography retrospective analysis

Purpose

The purpose of the study was to analyze the dimensions of socket morphology, interradicular bone dimensions, root length and morphology, buccal cortical bone thickness and gap defect between the implant bone in mandibular molars with cone beam computed tomography (CBCT) for immediate molar implant (IMI) placement.

Materials and methods

Sample sizes of 300 mandibular 1st and 2nd molars were each selected from the CBCT scans by inclusion and exclusion criteria. CBCT measurements were performed for socket size morphology, mesiodistal width, and buccolingual cancellous bone width at the crest at the apex. Width of the buccal cortical plate at the crest and interradicular bone (IRB) at the apex, 3 mm cervical to the apex and 6 mm cervical to the apex. Vertical parameters from the crest to furcation (L1), length from furcation to the apex (L2) and mesiodistal root morphology were measured to analyze the root configuration.

Results

All the parameters were analyzed for descriptive statistics for the mean and standard deviation. The majority were of Type B and C socket morphology with peri-implant bone defects of 2–2.5 mm, and the interradicular bone septum (IRB) was moderate for both first molar (1 M) and second molar (2 M) sites, but 2 M was shown to have less IRB than 1 M. Adequate buccal cortical bone thickness of 1.1 mm to 1.4 mm and buccolingual cancellous bone width were measured for both the 1 M and 2 M sites.

Conclusion

The morphology of the molar extraction socket determines the adequate stability for IMI. In mandibular molar teeth, where interradicular bone is incompetent in providing good primary stability, in addition to interradicular bone, clinicians should look for support from the apical bone and interdental septal bone for attaining primary stability of IMI.

Micro-tomographic analysis of the root trunk and pre-furcation area of the first mandibular molars

This study analyzed the root trunk (RT) and the pre-furcation area (PFA) of mandibular first molars. Thirty lower first mandibular molars extracted due to advanced periodontal disease were evaluated in a high-energy spiral computerized micro-tomography. Two gutta-percha markings on the cementoenamel junction (CEJ) and at the furcation entrance (FE) at buccal and lingual surfaces served as reference points for measurements of RT length, and PFA width and depth, at the levels of CEJ, 1 mm apical to CEJ, 2 mm apical to CEJ, and at the FE. The mean RT length was 2.49 mm at buccal and 3.18 mm at lingual sides. The mean widths of the PFA at CEJ, at 1 and 2 mm apical to CEJ, and at FE were 2.9, 3.4, 3.9 and 4.3 mm, respectively, while the mean depths were 0.19, 0.32, 0.57 and 1.1 mm, respectively. The PFA coincided with CEJ in 10 buccal and 10 lingual surfaces, representing 33.33% of the sample. There was a negative correlation between RT length and PFA dimensions. This study concludes that the RT length was smaller than previous studies. From the CEJ up to the furcation entrance, the PFA showed a progressive increase in width and depth. The coincidence of the PFA area beginning at the CEJ in 1/3, and the negative correlation between RT length and PFA dimensions may represent greater risk factor for the early development of furcation lesions.

Guided Tissue Regeneration Treatment Yields Better Results in Class II Furcations in the Mandible Than in the Maxilla: A Retrospective Study

Absorbable porcine collagen membrane with a bovine bone graft can be considered for regenerative treatment in periodontal class II furcation defects. We evaluated the clinical efficacy of guided tissue regeneration (GTR) treatment with bovine bone xenograft and a porcine collagen membrane in molars with class II furcations. Probing depth (PD), clinical attachment level (CAL), and bone level (BL) were recorded at baseline and at 3, 6, and 9 months postoperatively. Thirty class II furcation defects from the lower and upper molars were assessed. Significant improvements in PD and CAL were observed from baseline to 9 months in all groups (p < 0.01). BL improved in all groups except group A in the upper molars in radiographic assessment (p < 0.05). The lower and upper molars showed PD reduction of 50.5% ± 7.44% and 46.2% ± 11.2%, respectively, at 9 months (p = 0.044). In furcations of 1–3 mm, the lower and upper molars showed PD reductions of 51.2% ± 4.49% and 36.5% ± 16.14%, respectively (p = 0.035). The lower and upper molars showed a CAL gain of 51.1% ± 4.64% and 33.6% ± 18.8%, respectively (p = 0.037). Thus, GTR with bovine bone graft and porcine collagen membrane yielded good results in class II furcations, with better results in the lower than in the upper molars.

Morphometric Analysis of Furcation Areas of Multirooted Teeth in a Tunisian Population

Aims

The aim of the study was to evaluate the morphological characteristics of furcation of permanent molars in Tunisian population.

Materials and Methods

One hundred and four extracted maxillary and mandibular permanent molars were included in this study; comprising 34 maxillary first molars, 18 maxillary second molars, 33 mandibular first molars, and 19 mandibular second molars. For each tooth, the vertical dimension of the root trunk, root length, and interradicular space width were assessed with a micrometer caliber. Different types of root trunk in maxillary and mandibular molars were also analyzed. Statistical analysis was performed using a t-test.

Results

Root length decreased from the first to the second molars. This decrease seems to be pronounced at mandibular molars. The most observed root trunk type was type B, with a prevalence of 67.30% in maxillary molars and 51.92% in mandibular molars. The root trunk length increased from the first to the second molars in both maxillary and mandibular. The average width of the interradicular spaces varied on the same tooth and between the teeth.

Conclusion

This study provides epidemiological data about molars root length, interradicular space, and root trunk vertical dimension in a Tunisian population that could help clinicians in periodontal and endodontic therapy.

Incompatible amount of 3-D and 2-D periodontal attachments on micro-CT scanned premolars

Micro-computed tomography (micro-CT) was employed to relate the root surface area (RSA) to the periodontal attachment levels (PALs) of extracted premolars to diagnose periodontitis. Single-rooted human maxillary and mandibular premolars 31 and 36, respectively, were surveyed by micro-CT and its associated software. RSA levels from the 1st to 10th mm, corono-apically, were analyzed using statistical t tests. The average root length (RL) and RSA of the maxillary and mandibular premolars were significantly different (p < 0.05). Both premolars demonstrated a non-significant RSA percentage comparison at the evaluated PALs. For the 30% coronal 2-D radiographic RL, the 3-D RSAs 3.77 mm and 3.99 mm apical to the cementoenamel junction (CEJ) were 39.48% and 40.65% for maxillary and mandibular premolars, respectively. At the 15% coronal 2-D RL, the 3-D RSA 2 mm apical to the CEJ of the premolars was approximately 21%. At the 50% coronal 2-D RL level, approximately 62% coronal 3-D RSA and 6.5 mm RL decreased. The amount of decrease of the RSA attachment is significant in every 2-mm measurement for both premolars. Sampling periodontal microbial pathogens based on the condition of 2-D radiographic bone and clinical attachment losses without considering 3-D RSA is potentially inadequate and may underestimate the severity of the periodontitis.

Measurement of root surface area of permanent teeth in a Chinese population

OBJECTIVES

The aim of this study was to investigate the relation between the remaining area of periodontal attachment and the attachment levels for each type of permanent teeth in a Chinese population by using micro-computed tomography (micro-CT) scans.

DESIGN

A total of 440 extracted permanent teeth (including each tooth type except for the third molars) were collected from a Chinese population and scanned using a micro-CT. The CT data were input into Mimics 15.01 to generate 3D tooth models. To simulate various attachment levels, the roots were virtually cut at 0, 2, 4, 6, 8, and 10mm from the cemonto-enamel junction (CEJ). The net and percent remaining root surface area (RSA) were measured and calculated, and the data corresponding to attachment level were fitted to a linear function.

RESULTS

A Linear function can perfectly fit in relating the simulated attachment level to the net and percent remaining RSA (R²>0.99, and p<0.001 for each tooth type). For net remaining RSA, the slope of the linear function was steepest for maxillary first molars (b₁=-39.32) and least steep for mandibular central incisor (b₁=-13.08); whereas for the percentage of remaining RSA, the slopes (b₁) were relatively within a narrow range, from -7.40 (maxillary canine) to -9.64 (maxillary first molars).

CONCLUSION

Micro-CT offers simple and precise technique for quantitative analysis of the RSA. The total amount and vertical distribution of the RSA varied by tooth type. Linear formulas can perfectly describe the relation between the attachment level and the net and percent remaining RSA.

Measurement of root surface area of permanent teeth with root variations in a Chinese population-A micro-CT analysis

OBJECTIVES

This study investigated the influence of root variations on the root surface area (RSA) by using micro-CT scans.

DESIGN

A total of 228 extracted permanent teeth (2-rooted and single-rooted maxillary first premolars, mandibular first premolars with non-Tomes' and Tomes' roots, 2-rooted and 3-rooted mandibular first molars, and 2-rooted and C-shaped mandibular second molars) were collected in a Chinese population and scanned using a micro-CT. In Mimics 15.01, 3D tooth models were generated, and the net and percent remaining RSA at various simulated attachment levels were measured. The data corresponding to attachment level were fitted to a linear function.

RESULTS

The mean total RSA for different root forms decreased in the following order: 3-rooted>2-rooted>C-shaped>single-rooted. However, the differences were statistically significant (p<0.01) only for 2-rooted vs. single-rooted maxillary first premolars, and 2-rooted vs. C-shaped mandibular second molars. Linear functions can perfectly fit in relating the attachment level to the net and percent remaining RSA.

CONCLUSION

Micro-CT combined with Mimics software offers simple and precise technique for quantitative analysis of the RSA. Root variations may affect the total amount and vertical distribution of the net RSA. However, the degree of influence varies with the tooth type.

Analysis of periodontal attachment loss in relation to root form abnormalities

Purpose

The aim of this study was to explore root shape abnormalities, to investigate the influence of root form abnormalities on periodontal attachment loss, and to gather basic data to assist in the diagnosis and treatment of aggressive periodontitis.

Methods

From January 2010 to June 2012, a survey was conducted of all 3,284 periodontitis patients who visited the Department of Periodontology, Daejeon Dental Hospital, Wonkwang University School of Dentistry. Clinical parameters (probing depth, periodontal attachment loss, missing teeth) were measured and a radiographic examination was performed at the baseline. We classified the root shape abnormality of bicuspids and molars based on Meng classification.

Results

The periodontal attachment loss was the highest at the maxillary first molar (6.03 mm). The loss of the second molar was prominent. Type V deformity was shown to be the most common in the second maxillary and mandibular molars (P<0.05). Type V root shape was associated with the highest attachment loss (P=0.01).

Conclusions

Considering the small population and limited design of this study, definitive conclusions cannot be drawn. We suggest larger scale, methodologically more sophisticated studies that include normal controls and chronic periodontitis patients to clarify whether root form abnormalities are a potential risk factor for aggressive periodontitis.

Morphometric study of the root anatomy in furcation area of mandibular first molars

Furcation involvement in periodontal disease has been a challenge for the dentist.

Estimation of the remaining periodontal ligament from attachment-level measurements

AIM

Accurate assessment of the remaining area of periodontal attachment assists in determining the prognosis of a tooth. The aim of this study was to determine formulae to estimate the remaining area of periodontal attachment from attachment-level measures.

MATERIALS AND METHODS

Roots of 30 extracted teeth of each tooth type were coated with vinyl acetate solution and alpha-cyanoacrylate monomer to produce a membrane. The membrane was removed after guidelines were drawn to simulate various attachment levels. The root surface area on the apical side of each simulated attachment level was measured using image analysis software. The net or percent root surface area and corresponding attachment level data were fitted to a linear, quadratic, cubic, and exponential functions and a growth curve.

RESULTS

The linear function provided the most appropriate fit for the data. For net root surface area, a steeper slope was evident for tooth types with a larger mean total root surface area. For percent root surface area, a steeper slope was evident for tooth types with a shorter root length.

CONCLUSIONS

A linear function provides the most appropriate formula for estimation of the remaining area of periodontal attachment based on the attachment-level measurement.

Quantitative evaluation of the accuracy of micro-computed tomography in tooth measurement

Micro-computed tomography (MCT) is a noninvasive technique for visualizing morphological characteristics of teeth in a detailed and accurate manner, without causing any tooth destruction. A large amount of information can be obtained from such scans. The slices can be recreated in any plane, and the data can be represented as either two-dimensional (2D) or three-dimensional (3D) images. In addition, the internal and external anatomy can be demonstrated simultaneously or separately, and the images can be assessed qualitatively and quantitatively. However, only the qualitative accuracy of MCT had been evaluated previously. The aim of the present study was to evaluate the accuracy of MCT quantitatively by comparing the values obtained by MCT with those of other imaging methods. Twelve teeth were scanned using a desktop X-ray micro-CT scanner, and the images were reconstructed and measured. Values obtained by direct measurement served as the primary reference for linear measurements. Measurements made by a 3D scanner and by photography were additional references. MCT was found to be a reliable method of making linear measurements and may be a useful device for measuring distance and for observing both internal and external tooth structure using the reconstructed 3D form.

Regeneration of class II furcation defects: determinants of increased success

One of the most important indications for guided tissue regeneration (GTR) treatment is class II furcation lesion. However, periodontal regeneration of this type of defect, although possible, is not considered totally predictable, especially in terms of complete bone fill. Many factors may account for variability in the response to regenerative therapy in class II furcation. The purpose of this review is to assess the prognostic significance of factors related to the patient (smoking, stress, diabetes mellitus, acquired immunodeficiency syndrome and other acute and debilitating diseases, and the presence of multiple deep periodontal pockets), local factors (furcal anatomy, defect morphology, thickness of gingival tissue and tooth mobility), surgical treatment (infection control, bone replacement grafts combined with barriers or GTR alone, type of barrier and surgical technique), and postoperative period (plaque control, membrane exposure, membrane retrieval and a regular supportive periodontal care program) for successful of GTR in class II furcations.

Root Trunk Concavities as a Risk Factor for Regenerative Procedures of Class II Furcation Lesions in Humans

BACKGROUND

The purpose of this study was to evaluate the influence of root trunk concavities on guided tissue regeneration in humans and to determine if a modification in membrane design could improve the results.

METHODS

Ten patients who provided 10 pairs of similar Class II furcation defects were recruited for the study. Each defect was randomly assigned to treatment with either a normal expanded polytetrafluoroethylene (ePTFE) membrane (NM) or a modified ePTFE membrane (MM). The MM were made by removing the collar from an NM, cutting it into 2 mm segments, and suturing each of the segments to the collar of each MM. Following basic therapy, baseline clinical measurements were recorded using an acrylic stent, including probing depth (PD) and clinical attachment level (CAL). Full flaps were elevated, the defects were carefully debrided, and the root surfaces were decontaminated with manual and ultrasonic instruments. Hard tissue measurements were performed during surgery to determine vertical (VD) and horizontal defect (HD) depths. Then, NM and MM were sutured to their corresponding tooth and the flaps sutured. Membranes remained in position for 6 weeks. After 1 year, all sites were re-entered and soft and hard tissue measurements were recorded.

RESULTS

After 1 year, there were no statistically significant differences (Mann-Whitney test) between NM and MM groups in percentages of PD reduction (P= 0.27), CAL change (P= 0.26), or VD resolution (P = 0.13). However, percentage of HD resolution (NM: 24.3+/-11.8; MM: 44.8+/-16.0) was significantly different between groups (P= 0.008).

CONCLUSIONS

The modified membranes resulted in greater horizontal resolution of Class II furcation defects. The collars of the membranes should be modified to improve results when root trunk concavities are present.

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.

Crown lengthening in mandibular molars: a 5-year retrospective radiographic analysis

BACKGROUND

Crown lengthening procedures are a significant part of the periodontist's armamentarium. In order to recreate the clinical space lost to caries or trauma necessary for prosthetic restoration, osseous surgery is often required. If the procedure is not carefully planned, it may result in furcation involvement of multirooted teeth.

METHODS

Twenty-six subjects with 26 mandibular molar teeth requiring crown lengthening procedures prior to prosthetic crown placement were evaluated. Nineteen subjects with 24 prosthetic crowns on lower molars which had not undergone crown lengthening were included as control teeth. Bite-wing radiographs prior to surgery (for the test group) or placement of the crown (control group) and 5 years after completion of the prosthesis were compared and analyzed.

RESULTS

Of the 26 test teeth, 10 teeth (38.5%) were found to have radiographic evidence of furcation involvement, whereas none of the control teeth developed furcation invasions.

CONCLUSION

A critical distance from the furcation (CDF) of 4 mm was established as a landmark under which, if surgery was performed on mandibular molars, chances of furcation involvement in the future were very high.

Biometric study of the width, length and depth of the root trunk groove of human lower second molars

One hundred human lower second molars, 51 from the left side and 49 from the right side, extracted due to their poor clinical and radiographic conditions were utilized in this study. Using a Contracer apparatus, the profiles of the buccal and lingual root surfaces of these teeth were traced on a millimeter-scaled paper. The profiles were registered from the cementoenamel junction (CEJ), millimeter by millimeter, up to the entrance of the furcation. The width, length and depth of the root trunk groove, as well as the length of the root trunk, were studied. After statistical analysis (p < 0.05) it was possible to conclude that: a) the mean width of the root trunk groove on the buccal surface was 3.6 mm and, on the lingual surface, 3.3 mm; b) the mean depth of the root trunk groove on the buccal surface was 0.88 mm and, on the lingual surface, 0.77 mm; c) the mean length of the root trunk groove on the buccal surface was 2.93 mm and, on the lingual surface, 3.61 mm. The mean length of the root trunk on the buccal surface was 3.09 mm and, on the lingual surface, 3.91 mm (p < 0.025). There was a coincidence between the length of the root trunk and that of its groove in 90.2% of the buccal surfaces of the samples from the left side, and in 77.5% of the samples from the right side; on the lingual surface, the coincidence occurred in 77.5% of the teeth from the left side, and on 88.3% of the teeth from the right side. This work revealed that there is a concavity on the root trunk region of the lower second molar, whose depth and width were greater on the buccal surface and whose length was greater on the lingual surface. The depth of the root trunk groove increased in the apical direction, with maximum depth in the last millimeter of the root trunk. The root trunk was longer on the lingual surface than it was on the buccal surface.

Molar root anatomy and management of furcation defects

BACKGROUND, AIMS

Furcally-involved teeth present unique challenges to the success of periodontal therapy. Anatomical and morphological complicating factors dictate modifications in treatment approaches used for managing these areas.

METHOD

Various treatment approaches are available for furcally-involved teeth, the choice of which depends on selected interdependent factors.

RESULTS

These factors, along with various approaches used in the treatment of furcally compromised teeth are discussed in this review, with particular emphasis on morphology, etiology, classification and diagnosis.

Root trunk concavities as a risk factor for regenerative procedures of class II furcation lesions in dogs

BACKGROUND

The purpose of this study was to evaluate the influence of root trunk concavities on guided tissue regeneration.

METHODS

The second, third, and fourth mandibular bicuspids of 4 healthy mongrel dogs were used. Full flaps were elevated and furcation lesions (5 mm in height and 2 mm in depth) were surgically created. One mm deep concavities were prepared on the root trunks and part of the crown of all teeth. The second bicuspids remained as controls (C); the left third and fourth bicuspids received normal expanded polytetrafluoroethylene (ePTFE) membranes (NM) and the right bicuspids received modified ePTFE membranes (MM). The MM were made by removing the collar from an NM, cutting it into 2 mm segments, and suturing each of the segments to the collar of each MM. Normal and modified membranes were sutured to their corresponding teeth and the flaps sutured. After the healing period, the mandibles were removed and the teeth processed for histomorphometry.

RESULTS

The results showed that the junctional epithelium measured a mean of 0.71 mm for C, 0.64 mm for NM, and 0.14 mm for MM. The differences between C and MM and between NM and MM were both statistically significant at the 5% level (Kruskal-Wallis test). Mean bone height measurements for the buccal surfaces from the furcation roofs were 2.79 mm for C, 2.60 mm for NM, and 1.06 mm for MM and for the mid-portion 1.10 mm for C, 1.23 mm for NM, and 0.30 mm for MM. Differences were statistically significant at the 1% level between C and MM and between NM and MM for the buccal measurements, and at the 5% level between NM and MM for the mid-portion measurements.

CONCLUSIONS

Root trunk concavities are important risk factors for regenerative procedures. The collars of the membranes should be modified to improve results when concavities are present.

Anatomic characteristics of the furcation and root surfaces of molar teeth and their significance in the clinical management of marginal periodontitis

Treatment of periodontitis which involves the furcation area of molar teeth has always been a challenge. Sixty extracted human molar teeth were used for an anatomic study to clarify the possible morphologic factors which may affect the diagnosis, prognosis, and clinical management of periodontally involved teeth. Teeth were embedded in methylmethacrylate and cut in 70 microm cross sections from the cementoenamel junction to the apex. Cervical enamel projection, root and root trunk lengths, root proximities as well as depths of root concavities coronally, apically, and at the furcation roof were measured. Cervical enamel projections were observed in 30% of the teeth examined. The shortest root trunk was found at the buccal aspect of mandibular first molars, permitting furcation involvement at early stages of periodontal disease. The most apically located furcation was found at the distal site of maxillary first molars. Furcation roofs showed severe concavities and complex cementum morphology. Teeth exhibiting cervical enamel projection were found to have deeper root concavities compared to teeth without cervical enamel projection and mesial roots of mandibular molars possessed greater furcal concavities than distal roots. The presence of root concavities complicates the diagnosis of furcation involvement and restricts access of periodontal instruments, resulting in incomplete treatment. Furcation anatomy may also influence the long-term prognosis of the teeth by favoring the retention of bacterial deposits and making oral hygiene procedures almost impossible. The present study shows that knowledge of a tooth's unique anatomic characteristics is a prerequisite for effective periodontal therapy.

Instrumentation of furcation with modified sonic scaler inserts: study on manikins, part I

The purpose of this study was to determine the suitability of different scaling instruments for the debridement of furcations. 12 upper and 12 lower replicated molars with through-and-through furcations were instrumented 3x with 5 different types of instruments: (i) hand instruments; (ii) hand instruments in conjunction with diamond burrs; (iii) a conventional ultrasonic scaler insert; (iv) a conventional sonic scaler insert; (v) a set of 2 modified diamond coated sonic scaler inserts with different angulated shafts. The plastic replicas were fixed in a manikin head without replicated soft tissues. Following debridement, weight loss and % of instrumented furcation area were assessed. In the case of lower molars, it made little difference whether they were treated with hand instruments, hand instruments combined with diamond burrs, or diamond-coated sonic scaler inserts. On upper molars, however, significantly more area was instrumented with the diamond-coated inserts than with the other instruments. Substance removal was greater with diamond-coated inserts than with the other devices. In conclusion, an effective debridement of the furcation seems possible only with an odontoplasty, in which a furcation is fitted to the instrument by means of intensive instrumentation, thus leading to substance loss. To improve results with these instruments, further research is necessary.

Clinical comparison of cellulose and expanded polytetrafluoroethylene membranes in the treatment of class II furcations in mandibular molars with 6-month re-entry

The present study compared two barrier membranes, ePTFE and cellulose, used to treat Class II furcations in mandibular molars. Fifteen patients with no history of systemic diseases and presenting matched pair defects were selected. The following soft tissue measurements were taken at baseline (after the hygienic phase), and 6 months after surgery: gingival recession, probing depth, clinical attachment level, and width of keratinized tissue. At the time of membrane placement, and 6 months later (re-entry), the following hard tissue parameters were recorded: cemento-enamel junction (CEJ) to alveolar crest, CEJ to base of osseous defect, alveolar crest to base of osseous defect, and horizontal defect depth. According to the surgical protocol, the ePTFE membranes were completely covered by the flaps (subgingival placement), whereas the cellulose membranes extended 1 mm coronal to the gingival margin (supragingival placement). Healing was uneventful in all cases and membranes remained in place for 4 weeks. Data were analyzed using the Wilcoxon signed-rank test at the 5% level of significance. No statistically significant differences were found between the ePTFE and cellulose membranes, respectively (in mm): probing depth reduction (2.87+/-1.0 versus 3.27+/-1.1), gain in attachment level (2.53+/-1.2 versus 2.8+/-1.3), defect fill (3.0+/-1.4 versus 4.0+/-2.3), horizontal furcation fill (2.87+/-1.1 versus 2.93+/-1.0), alveolar crest resorption (2.4+/-10 versus 2.73+/-1.2), and intrabony defect fill (0.6+/-1.2 versus 1.27+/-1.7). We conclude that both ePTFE and cellulose membranes are effective, not showing statistical differences in efficacy. A larger study may be necessary to show differences in efficacy and adverse effects.

Bacterial colonization of the external and internal sulci and of cellulose membranes at time of retrieval

Membrane exposure with bacterial contamination is often considered one of the main reasons for the lack of predictability in achieving complete regeneration of periodontal defects. Ten cellulose membranes, retrieved from 7 patients treated for Class II furcation lesions in lower molars with at least 4 mm of exposure at time of retrieval were studied. Contamination of exposed membranes was studied using SEM analysis of four surfaces of the membrane, upper external, lower external, upper internal, and lower internal surfaces. DNA probe analysis of three periodontopathic bacteria, Porphyromonas gingivalis, Prevotella intermedia, and Actinobacillus actinmycetemcomitans, was carried out for specimens collected from the external and internal sulci. The results suggest that bacterial contamination of the membranes could be controlled if proper pre- and postoperative care is followed, since significant amounts of any of the three periodontopathogenic bacteria studied were not found. The SEM analysis corroborated the DNA probe analysis since the predominant morphotypes detected were not suggestive of periodontopathogenic bacteria. The importance of membrane contamination and of root concavities in the lack of predictability of the GTR procedure is discussed.

A meta-analysis of normal ranges for root surface areas of the permanent dentition

The typical values and normal ranges of the permanent dentition root surface areas were estimated based on a meta-analysis of 4730 root surface area measurements collected from 22 published studies between 1950 and 1992. A typical dentition root surface area, excluding 3rd molars, was 75 cm2, and 95% of the dentitions had a total root surface area somewhere between 65 cm2 and 86 cm2. The prognostic significance of particular values of root surface areas for dental treatment outcomes requires further investigation.

Calculus removal from multirooted teeth with and without surgical access. II. Comparison between external and furcation surfaces and effect of furcation entrance width

The purpose of this study was to evaluate the effect of furcation entrance width on the efficacy of calculus removal from furcation areas as well as to compare this efficacy between external and furcation surfaces after closed root planing, open root planing and use of a rotary diamond for the furcation area. 30 first and second lower molars scheduled for extraction with a calculus index > or = 2 and a degree II or III furcation involvement were divided into 3 groups: 10 molars were scaled and root planed using a closed approach: 10 molars were scaled and root planed using an open approach; 10 molars were scaled and root planed with an open approach and rotary diamond was used for removal of deposits in the furcation area. After extraction, the width of the furcation entrance was measured buccally and lingually 2 mm apical from the bifurcation and furcations were categorized as wide (width > 2.4 mm) or narrow (width < 2.4 mm). The teeth were assessed in a stereomicroscope and the % of residual calculus on external and furcation surfaces was calculated. The width of the furcation entrance influenced the efficacy in root planning in the open group (p = 0.0015). The use of rotary diamond was the most effective method for removing calculus both for narrow and wide furcations. The effectiveness of open root planning in the mesial root was related to the width of the furcation entrance where the % of residual calculus was significantly higher for narrow furcations (p = 0.008).(ABSTRACT TRUNCATED AT 250 WORDS)

The validity of periodontal probing as a method of measuring loss of attachment

Linear probe measurements are used to assess the severity and extent of attachment loss in chronic periodontitis and to identify, retrospectively, sites of disease activity. The use of the probe for these purposes is based on the implicit assumption that there is a direct and predictable relationship between linear probe measurements of attachment loss and the area of cemental surface which has been denuded of periodontal ligament. The aim of this study was to test this assumption by determining the correlation between loss of attachment as expressed by probe readings, and that expressed as the area of denuded root surface. The areas of denuded root surface of 236 teeth of different morphotype in 41 human dried skulls were determined by a rubber base impression technique and compared with their corresponding probe measurements, made at 10 sites per tooth. Although the majority of correlations between linear and area measurements were statistically significant for some individual morphotypes and categories of bone loss, there was overall, no consistent pattern of correlation between the two parameters. Furthermore, many correlations which were statistically significant had low values of the correlation coefficient: Kendall's T. It was concluded that probe readings are not a very precise measure of attachment loss, particularly with increasing severity destruction. These results cast doubt on the ability of individual linear measurements to represent the true severity of attachment loss, and thus on the precision of loss of attachment charts for retrospectively identifying sites of periodontal disease activity.

The effectiveness of two sonic and two ultrasonic scaler tips in furcations

This study compared the effectiveness of two sonic and two ultrasonic scaler tips on artificial calculus removal from the furcations of mandibular first and second molars. Twenty-four extracted mandibular molars were cleaned and randomly assigned to one of four treatment groups. Teeth were split buccal lingually, artificial calculus was placed in the furcation areas, and the teeth were photographed with a stereo camera. Teeth were reconnected with bonding material and mounted in a typodont with simulated gingiva and attached to a dental chair. Teeth were instrumented with either a Cavitron TFI10 tip, Cavitron EWPP tip, Titan-S Universal tip, or Titan-S Sickle tip by a licensed dental hygienist until each tooth was judged calculus free to the touch with a CH3 explorer. Time for each instrumentation period was recorded. Following instrumentation, the teeth were again split and photographed. Stereophotogrammetry was used to produce tracings of the teeth with initial calculus and remaining calculus. Pre-instrumentation and post-instrumentation amounts of calculus on the surface area were computed using the Bioquant system. A two factor analysis of variance was conducted followed with a Newman-Keuls Multiple Comparison Technique to test for within and between differences. Significant differences (P less than or equal to 0.01) were found between pre- and post-amounts of calculus for all tips. No significant differences (P less than or equal to 0.05) were found between the four instrument tips with respect to percentage of furcation surface with calculus remaining. No differences were found between tips with regard to the time required to clean the test surfaces.

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.