Treatment of periodontal furcation defects. Coronally positioned flaps versus dura mater membranes in class II defects

Regenerative surgical treatment of furcation defects: A systematic review and Bayesian network meta-analysis of randomized clinical trials

AIMS

To investigate the clinical performance of regenerative periodontal surgery in the treatment of furcation defects versus open flap debridement (OFD) and to compare different regenerative modalities.

MATERIAL AND METHODS

A systematic search was conducted to identify RCTs evaluating regenerative surgical treatment of furcations with a minimum of 12-month follow-up. Three authors independently reviewed, selected and extracted data from the search conducted and assessed risk of bias. Primary outcomes were tooth loss, furcation improvement (closure/conversion) (FImp), gain of horizontal bone level (HBL) and attachment level (HCAL). Secondary outcomes were gain in vertical attachment level (VCAL), probing pocket depth (PPD) reduction, PROMs and adverse events. Data were summarized into Bayesian standard and network meta-analysis in order to estimate direct and indirect treatment effects and to establish a ranking of treatments.

RESULTS

The search identified 19 articles, reporting on 20 RCTs (19 on class II, 1 on class III furcations) with a total of 575 patients/787 defects. Tooth loss was not reported. Furcation closure ranged between 0% and 60% (10 trials), and class I conversion from 29% to 100% (six trials). Regenerative techniques were superior to OFD for FImp (OR = 20.9; 90% CrI = 5.81, 69.41), HCAL gain (1.6 mm), VCAL gain (1.3 mm) and PPD reduction (1.3 mm). Bone replacement grafts (BRG) resulted in the highest probability (Pr = 61%) of being the best treatment for HBL gain. Non-resorbable membranes + BRG ranked as the best treatment for VCAL gain (Pr = 75%) and PPD reduction (Pr = 56%).

CONCLUSIONS

Regenerative surgery of class II furcations is superior to OFD. FImp (furcation closure or class I conversion) can be expected for the majority of defects. Treatment modalities involving BRG are associated with higher performance.

Periodontal regeneration - furcation defects: a systematic review from the AAP Regeneration Workshop

BACKGROUND

The aim of this review is to present the available evidence regarding the effectiveness of different regenerative approaches for the treatment of furcation defects in specific clinical scenarios compared with conventional surgical therapy to provide clinical guidelines for the therapeutic management of furcation defects and to identify priorities for future research that may advance the understanding of periodontal regenerative medicine.

METHODS

A comprehensive search based on predetermined eligibility criteria was conducted to identify human original studies and systematic reviews on the topic of periodontal regeneration of furcation defects. Two reviewers independently screened the title and abstract of the entries yielded from the initial search. Subsequently, both reviewers read the full-text version of potentially eligible studies, made a final article selection, and extracted the data of the selected studies considering specific clinical scenarios. The clinical scenarios contemplated in this review included the following: 1) facial and interproximal Class I defects in maxillary molars; 2) facial and lingual Class I defects in mandibular molars; 3) facial and interproximal Class II furcation defects in maxillary molars; 4) facial and lingual Class II furcation defects in mandibular molars; 5) Class III furcation defects in maxillary molars; 6) Class III furcation defects in mandibular molars; and 7) Class I, II, or III furcation defects in maxillary premolars. Endpoints of interest included different clinical, radiographic, microbiologic, histologic, and patient-reported outcomes.

RESULTS

The initial search yielded a total of 1,500 entries. The final selection consisted of 150 articles, of which six were systematic reviews, 109 were clinical trials, 27 were case series, and eight were case reports. A summary of the main findings of previously published systematic reviews and the available evidence relative to the indication of regenerative approaches for the treatment of furcation defects compared with conventional surgical therapy are presented. Given the marked methodologic heterogeneity and the wide variety of materials and techniques applied in the selected clinical trials, the conduction of a meta-analysis was not viable.

CONCLUSIONS

On the basis of the reviewed evidence, the following conclusions can be drawn. 1) Periodontal regeneration has been demonstrated histologically and clinically for the treatment of maxillary facial or interproximal and mandibular facial or lingual Class II furcation defects. 2) Although periodontal regeneration has been demonstrated histologically for the treatment of mandibular Class III defects, the evidence is limited to one case report. 3) Evidence supporting regenerative therapy in maxillary Class III furcation defects in maxillary molars is limited to clinical case reports. 4) In Class I furcation defects, regenerative therapy may be beneficial in certain clinical scenarios, although most Class I furcation defects may be successfully treated with non-regenerative therapy. 5) Future research efforts should be primarily directed toward the conduction of clinical trials to test novel regenerative approaches that place emphasis primarily on patient-reported outcomes and also on histologic demonstration of periodontal regeneration. Investigators should also focus on understanding the influence that local, systemic, and technical factors may have on the outcomes of regenerative therapy in furcation defects.

Position Paper: Periodontal Regeneration

Untreated periodontal disease leads to tooth loss through destruction of the attachment apparatus and tooth-supporting structures. The goals of periodontal therapy include not only the arrest of periodontal disease progression,but also the regeneration of structures lost to disease where appropriate. Conventional surgical approaches (e.g., flap debridement) continue to offer time-tested and reliable methods to access root surfaces,reduce periodontal pockets, and attain improved periodontal form/architecture. However, these techniques offer only limited potential towards recovering tissues destroyed during earlier disease phases. Recently, surgical procedures aimed at greater and more predictable regeneration of periodontal tissues and functional attachment close to their original level have been developed, analyzed, and employed in clinical practice. This paper provides a review of the current understanding of the mechanisms, cells, and factors required for regeneration of the periodontium and of procedures used to restore periodontal tissues around natural teeth. Targeted audiences for this paper are periodontists and/or researchers with an interest in improving the predictability of regenerative procedures. This paper replaces the version published in 1993.

Periodontal Regenerative Potential of Autogenous Periodontal Ligament Grafts in Class II Furcation Defects

BACKGROUND

The aim of the present study was to evaluate the regenerative potential of autogenous periodontal ligament (PDL) grafts in the treatment of Class II furcation defects.

METHODS

Twenty mandibular Class II furcation defects from 10 systemically healthy patients with chronic periodontitis were selected. In experimental defects, flaps were coronally positioned following placing autogenous PDL grafts that were obtained from third molars; in controls, coronally advanced flap procedure without graft was applied. Clinical measurements including plaque index, gingival index, probing depth (PD), vertical and horizontal clinical attachment level (CAL), and gingival recession (GR) were obtained at baseline and after 3 and 6 months postoperatively. Vertical and horizontal defect fill was evaluated with open clinical measurements at initial surgery and reentry after 6 months. Gingival biopsies from the experimental and control defects were obtained at reentry and evaluated histopathologically in order to examine the soft tissue response towards PDL grafts.

RESULTS

Sites treated with PDL grafts demonstrated significant improvement in vertical and horizontal defect fill, PD, and CAL at 3 and 6 months compared to presurgical values. The difference determined for the PD values of both groups at a statistically significant degree in favor of grafted sites was maintained at all observation periods. No foreign body reaction was observed in PDL grafts.

CONCLUSIONS

These short-term results point to the potential of PDL grafts in promoting healing of furcation lesions. This preliminary study suggests that the use of PDL grafts may have beneficial effects in the treatment of furcation defects.

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.

The efficacy of bone replacement grafts in the treatment of periodontal osseous defects. A systematic review

BACKGROUND

Bone replacement grafts (BRG) are widely used in the treatment of periodontal osseous defects; however, the clinical benefits of this therapeutic practice require further clarification through a systematic review of randomized controlled studies.

RATIONALE

The purpose of this systematic review is to access the efficacy of bone replacement grafts in proving demonstrable clinical improvements in periodontal osseous defects compared to surgical debridement alone.

FOCUSED QUESTION

What is the effect of bone replacement grafts compared to other interventions on clinical, radiographic, adverse, and patient-centered outcomes in patients with periodontal osseous defects?

SEARCH PROTOCOL

The computerized bibliographical databases MEDLINE and EMBASE were searched from 1966 and 1974, respectively, to October 2002 for randomized controlled studies in which bone replacement grafts were compared to other surgical interventions in the treatment of periodontal osseous defects. The search strategy included screening of review articles and reference lists of retrieved articles as well as hand searches of selected journals.

INCLUSION CRITERIA

All searches were limited to human studies in English language publications.

EXCLUSION CRITERIA

Non-randomized observational studies (e.g., case reports, case series), publications providing summary statistics without variance estimates or data to permit computation, and studies without BRG intervention alone were excluded.

DATA COLLECTION AND ANALYSIS

The therapeutic endpoints examined included changes in bone level, clinical attachment level, probing depth, gingival recession, and crestal resorption. For purposes of meta-analysis, change in bone level (bone fill) was used as the primary outcome measure, measured upon surgical re-entry or transgingival probing (sounding).

MAIN RESULTS

1. Forty-nine controlled studies met eligibility criteria and provided clinical outcome data on intrabony defects following grafting procedures. 2. Seventeen studies provided clinical outcome data on BRG materials for the treatment of furcation defects.

REVIEWERS' CONCLUSIONS

1. With respect to the treatment of intrabony defects, the results of meta-analysis supported the following conclusions: 1) bone grafts increase bone level, reduce crestal bone loss, increase clinical attachment level, and reduce probing depth compared to open flap debridement (OFD) procedures; 2) No differences in clinical outcome measures emerge between particulate bone allograft and calcium phosphate (hydroxyapatite) ceramic grafts; and 3) bone grafts in combination with barrier membranes increase clinical attachment level and reduce probing depth compared to graft alone. 2. With respect to the treatment of furcation defects, 15 controlled studies provided data on clinical outcomes. Insufficient studies of comparable design were available to submit data to meta-analysis. Nonetheless, outcome data from these studies generally indicated positive clinical benefits with the use of grafts in the treatment of Class II furcations. 3. With respect to histological outcome parameters, 2 randomized controlled studies provide evidence that demineralized freeze-dried bone allograft (DFDBA) supports the formation of a new attachment apparatus in intrabony defects, whereas OFD results in periodontal repair characterized primarily by the formation of a long junctional epithelial attachment. Multiple observational studies provide consistent histological evidence that autogenous and demineralized allogeneic bone grafts support the formation of new attachment. Limited data also suggest that xenogenic bone grafts can support the formation of a new attachment apparatus. In contrast, essentially all available data indicate that alloplastic grafts support periodontal repair rather than regeneration. 4. The results of this systematic review indicate that bone replacement grafts provide demonstrable clinical improvements in periodontal osseous defects compared to surgical debridement alone.

A systematic review of guided tissue regeneration for periodontal furcation defects. What is the effect of guided tissue regeneration compared with surgical debridement in the treatment of furcation defects?

OBJECTIVES

To systematically review the evidence of effectiveness of guided tissue regeneration (GTR) for furcation defects.

BACKGROUND

The evidence for the effectiveness of GTR in furcation defects has not yet been systematically appraised.

METHODS

We searched for randomized controlled trials with at least 6 months' follow-up comparing GTR with surgical debridement (open flap debridement, OFD). Data sources included electronic databases, hand-searched journals and contact with experts. Screening, data abstraction and quality assessment were conducted independently by multiple reviewers. The primary outcome measure was reduction in open horizontal furcation depth, secondary outcomes were frequency of furcation closure, gain in horizontal and vertical probing attachment and reduction of vertical probing depth.

RESULTS

For the primary outcome, reduction in horizontal furcation depth assessed during re-entry, the weighted mean difference between GTR and control was 1.51 mm (95% CI [0.39-2.62], chi-square for heterogeneity 67.6 (df = 3), P < 0.001) in mandibular class II furcations, 1.05 mm (95% CI [0.46-1.64, chi-square for heterogeneity 34.9 (df = 3), P < 0.001) in maxillary class II furcations, and 0.87 mm (95% CI [-0.08-1.82], chi-square for heterogeneity 0.1 (df = 4), P = 0.991) in studies that had combined mandibular and maxillary class II furcations. For the secondary outcomes, GTR treatment led to significantly better results than open flap debridement. No meta-analysis could be performed for frequency of furcation closure because of sparse data.

CONCLUSIONS

Overall, GTR was consistently more effective than OFD in reducing open horizontal furcation depths, horizontal and vertical attachment levels and pocket depths for mandibular or maxillary class II furcation defects. However, these improvements were modest, variable and there was only a limited number of studies available to appraise the effects, thus limiting general conclusions about the clinical benefit of GTR. Future studies should aim to identify factors associated with achieving consistent and more pronounced benefits over open flap debridement.

Medical grade calcium sulfate hemihydrate versus expanded polytetrafluoroethylene in the treatment of mandibular class II furcations

BACKGROUND

Guided tissue regeneration (GTR) techniques have been reported to enhance bone regeneration of molar furcation defects. The current trends in therapy encourage the use of a bioabsorbable barrier. The efficacy of the bioabsorbable barrier needs to be equal to, if not better than, the non-absorbable barrier.

METHODS

This clinical study compared the bone regeneration capacity of a commonly used GTR procedure (demineralized freeze-dried bone allograft [DFDBA] and an expanded polytetrafluoroethylene [ePTFE] membrane) to DFDBA and an exclusion barrier of medical grade calcium sulfate hemihydrate [MGCSH]). Thirteen pairs of mandibular molar Class II furcation defects were evaluated in 13 patients. Clinical measurements of keratinized gingival width, probing depth, and recession were recorded prior to treatment. Following flap elevation and furcation defect debridement, an occlusal reference stent and periodontal probes were used to measure vertical, horizontal, and intrabony defect dimensions to the nearest millimeter. Paired defects were randomly assigned to receive either DFDBA/ePTFE or DFDBA/MGCSH. At 6 months, study sites were surgically re-entered and the treated furcations were debrided to a firm bone surface. Intraoperative measurements were repeated. Clinical measurements were repeated at 12 months.

RESULTS

The MGCSH-treated furcations demonstrated mean probing depth reduction between baseline and 6 months (1.00 +/- 0.82 mm, P<0.05) and baseline and 12 months (1.31 +/- 0.85 mm, P<0.05). There was no statistically significant change in probing depth in the ePTFE group at any time interval. The horizontal defect fill was significantly greater for ePTFE (36.7%) versus MGCSH (23.8%) (P<0.02).

CONCLUSIONS

In selected defects, improved clinical measurements were achieved with DFDBA/MGCSH as well as DFDBA/ePTFE. Both treatments obtained significant horizontal defect fill at 6 months. DFDBA/ePTFE showed a significantly greater horizontal defect fill compared to DFDBA/MGCSH. Attachment level gains achieved with MGCSH held for 12 months, whereas ePTFE attachment level gains did not.

A clinical comparison of the new attachment obtained by guided tissue regeneration and coronally positioned flap techniques in the management of human molar furcation defects

The present clinical trial was designed to evaluate the regenerative potential of the periodontal tissue in Class II furcation defects in mandibular molars using reconstructive surgery based on the guided tissue regeneration (GTR) technique versus the coronally positioned flap (CPF) technique. After the completion of the initial phase of therapy and four to six weeks healing period, 20 furcation-involved molars were examined for baseline data which included plaque index, gingival condition, probing depth (PD), probing attachment level (PAL-V, PAL-H) and radiographs. All parameters were reexamined after three, six and twelve months of healing, except PD, PAL-V and PAL-H which were not measured at three and six months. A nonparametric analysis was used. The study showed that there were no significant differences in the mean baseline measurements between the treatment groups. After 12 months following surgical treatment, both GTR and CPF procedures showed gains in new clinical attachment levels. When comparing parameters between the two surgical procedures, GTR molars showed significantly more improvement in probing depth as well as vertical and horizontal attachment level of the interradicular osseous defect than did the CPF molars (p < 0.05). About 80 per cent of the sites treated with the GTR technique showed complete clinical resolution of the furcation problem. CPF therapy reached the same Treatment goal in about 50 per cent of the cases which were treated. Guided tissue regeneration appeared to be more effective in promoting regeneration than the coronally positioned flap.

Evaluation of periosteal membranes and coronally positioned flaps in the treatment of Class II furcation defects: a comparative clinical study in humans

The purpose of this study was to compare the clinical effectiveness of connective tissue grafts including periosteum used as a mechanical barrier for guided periodontal tissue regeneration and coronally positioned flaps in the treatment of Class II furcation defects. A total of 28 furcation defects were treated; 14 received a periosteal barrier and 14 received a coronally positioned flap. Reentry surgeries were performed at 6 months. No statistically significant differences were found preoperatively between the two treatment groups with respect to clinical parameters and osseous measurements. Postsurgically, both treatment modalities resulted in a significant decrease in probing depth and a significant gain in clinical attachment, but the differences observed were not statistically significant. The periosteal barrier group presented with a significantly better gain in vertical components of the alveolar bone (1.93 +/- 0.15 mm and 0.20 +/- 0.26 mm for periosteal barrier and coronally positioned flap groups, respectively; P < or = 0.001) and horizontal components of the alveolar bone (1.60 +/- 0.21 mm and 0.13 +/- 0.90 mm for periosteal barrier and coronally positioned flap groups, respectively; P < or = 0.001). The results of this trial indicate that similar clinical resolution of Class II furcation defects can be obtained with periosteal barriers and coronally positioned flaps. Periosteal barriers, however, are a better treatment alternative in achieving bone fill of the furcation area.

Local mechanical anisotropy in human cranial dura mater allografts

Human cranial dura mater (CDM) allograft's success as a repair biomaterial is partly due to its high mechanical strength, which facilitates its ability to form water-tight barriers and resist high in-vivo mechanical loads. Previous studies on CDM allograft mechanical behavior used large test specimens and concluded that the allograft was mechanically isotropic. However, we have quantified CDM microstructure using small angle light scattering (SALS) and found regions of well-aligned fibers displaying structural symmetry between the right and left halves (Jimenez et al., 1998). The high degree of fiber alignment in these regions suggests that they are mechanically anisotropic. However, identification of these regions using SALS requires irreversible tissue dehydration, which may affect mechanical properties. Instead, we utilized CDM structural symmetry to estimate the fiber architecture of one half of the CDM using computer graphics to flip the SALS fiber architecture map of the corresponding half about the plane of symmetry. Test specimens (20 mm x 4 mm) were selected parallel and perpendicular to the preferred fiber directions and subjected to uniaxial mechanical failure testing. CDM allografts were found to be locally anisotropic, having an ultimate tensile strength (UTS) parallel to the fibers of 12.76 +/- 1.65 MPa, and perpendicular to the fibers of 5.21 +/- 1.01 MPa (mean +/- sem). These results indicate that uniaxial mechanical tests on large samples used in previous studies tended to mask the local anisotropic nature of the smaller constituent sections. The testing methods established in this study can be used in the evaluation of new CDM processing methods and post-implant allograft mechanical integrity.

Long-term maintenance of alveolar bone gain after implantation of autolyzed, antigen-extracted, allogenic bone in periodontal intraosseous defects

This randomized controlled trial assessed the long-term maintenance of alveolar bone gain after implantation of autolyzed, antigen-extracted, allogenic (AAA) bone. AAA bone is a demineralized freeze-dried bone allograft processed after previously described methods. In each of 14 patients, AAA bone was implanted into the intraosseous defect of 1 tooth (test); a second tooth with an intraosseous defect was treated by modified Widman flap surgery alone (control). All patients were offered supportive periodontal therapy at 3- to 6-month intervals following treatment. Clinical measurements were taken prior to surgery, 6 months, and 3 years following surgery. Of the 14 patients enrolled, 11 patients completed the 6-month and 8 patients the 3-year examination. In test teeth, bone gain was significantly greater compared to control teeth at 6 months (2.2+/-0.5 mm and 1.2+/-0.5 mm, respectively) and 3 years (2.3+/-0.7 mm and 1.1+/-0.8 mm, respectively) (P < 0.05). Also, more probing attachment was gained in test compared to control teeth at 3 years (2.0+/-0.7 mm and 0.8+/-0.5 mm, respectively; P < 0.05). At 3 years, Porphyromonas gingivalis was detected in 3 test and 2 control teeth by polymerase chain reaction, whereas no Actinobacillus actinomycetemcomitans was found. Due to the low detection frequency, there was no clear correlation between the maintenance of alveolar bone during supportive periodontal therapy and subgingival infection with P. gingivalis. The data indicated that alveolar bone gain after implantation of AAA bone may be maintained over a minimum of 3 years in patients receiving periodontal supportive therapy.

Six-year clinical evaluation of HTR synthetic bone grafts in human grade II molar furcations

A biocompatible microporous composite of PMMA (poly-methyl-methacrylate), PHEMA (poly-hydroxy-ethyl-methacrylate) and calcium hydroxide bone replacement graft material (Bioplant HTR Synthetic Bone) was evaluated in 16 maxillary molar and 10 mandibular molar Grade II furcations in 13 patients. Following initial preparation, full thickness flaps were raised to gain access to the furcations; mechanical hand and ultrasonic root and defect debridement and chemical tetracycline root preparation were performed; furcation and adjacent osseous defects in each patient were grafted with HTR Synthetic Bone; and the host flaps replaced or slightly coronally positioned. Weekly, then monthly deplaquing was performed until surgical re-entry at 6-12 months. Patients were then followed on approximate 3-month recalls for > or = 6 yr. Evaluation of the primary clinical outcome of furcation grade change showed that in the maxilla 5/16 furcations were clinically closed, 9/16 were Grade I, and 2/16 remained Grade II; while in the mandible 3/10 were clinically closed, 5/10 were Grade I, and 2/10 remained Grade II. Other significant clinical changes included decrease in mean horizontal furcation probing attachment level from 4.4 mm at surgery to 2.2 mm at re-entry to 2.0 mm at 6 yr, decrease in probing pocket depth from 5.4 mm at surgery to 3.0 mm at re-entry to 3.2 mm at 6 yr, and improvement in vertical clinical probing attachment level from 5.4 mm at surgery to 4.2 mm at re-entry to 4.1 mm at 6 yr (all p < 0.05 from surgery to re-entry and surgery to 6 yr, n.s. from re-entry to 6 yr via ANOVA). These favorable results with HTR polymer are similar to several reports with other graft materials and with GTR barriers, and suggest that HTR polymer may have a beneficial effect in the clinical management of Grade II molar furcations.

Periodontal regeneration around natural teeth

1. Evidence is conclusive (Table 2) that periodontal regeneration in humans is possible following the use of bone grafts, guided tissue regeneration procedures, both without and in combination with bone grafts, and root demineralization procedures. 2. Clinically guided tissue regeneration procedures have demonstrated significant positive clinical change beyond that achieved with debridement alone in treating mandibular and maxillary (buccal only) Class II furcations. Similar data exist for intraosseous defects. Evidence suggests that the use of bone grafts or GTR procedures produce equal clinical benefit in treating intraosseous defects. Further research is necessary to evaluate GTR procedures compared to, or combined with, bone grafts in treating intraosseous defects. 3. Although there are some data suggesting hopeful results in Class II furcations, the clinical advantage of procedures combining present regenerative techniques remains to be demonstrated. Additional randomized controlled trials with sufficient power are needed to demonstrate the potential usefulness of these techniques. 4. Outcomes following regenerative attempts remain somewhat variable with differences in results between studies and individual subjects. Some of this variability is likely patient related in terms of compliance with plaque control and maintenance procedures, as well as personal habits; e.g., smoking. Variations in the defects selected for study may also affect predictability of outcomes along with other factors. 5. There is evidence to suggest that present regenerative techniques lead to significant amounts of regeneration at localized sites on specific teeth. However, if complete regeneration is to become a reality, additional stimuli to enhance the regenerative process are likely needed. Perhaps this will be accomplished in the future, with combined procedures that include appropriate polypeptide growth factors or tissue factors to provide additional stimulus.

Multi-center evaluation of bioabsorbable collagen membrane for guided tissue regeneration in human Class II furcations

Clinical data related to GTR therapy for Class II furcations were analyzed from 7 treatment centers that evaluated one of two possible treatment pairs, either bioabsorbable collagen membrane (Type I bovine tendon collagen) (COLL) versus control surgical debridement (DEBR) or COLL versus expanded polytetrafluoroethylene (ePTFE). After initial preparation and re-evaluation, full thickness flaps were reflected, the defects debrided, and the roots planed. Furcations and associated bony defects in each patient were randomly assigned to one of the 2 treatments in each pair, and the flaps closed. Patients received quarterly periodontal maintenance until surgical re-entry at 6 to 12 (mean 11.1) months. Data from 59 pairs of Class II furcations were analyzed via paired t, Wilcoxon signed rank, and RM ANOVA tests. COLL showed better results than DEBR for vertical defect fill, percent defect resolution, and horizontal furcation fill. When COLL was compared to ePTFE in furcations across patients, no differences were found. Both COLL and ePTFE resulted in an improvement in clinical furcation Class about 50% of the time (compared to 7% frequency with DEBR). COLL use yielded 8 and ePTFE yielded 1 clinically-complete furcation closures. COLL barriers resulted in generally favorable clinical results in furcation defects, appeared to be better than DEBR alone, and were at least similar to and often better than ePTFE. COLL of the type used in this study appears to be a useful and beneficial material for regenerative therapy in Class II furcation type periodontal defects.

A comparative clinical study: the use of human type I collagen with and without the addition of metronidazole in the GTR method of treatment of periodontal disease

This investigation was undertaken to evaluate cross-linked human type I collagen, with and without added metronidazole, when used as a barrier membrane in the guided tissue regeneration (GTR) principle of treatment for periodontal disease. 16 patients suffering from moderate to severe periodontitis with 78 bilaterally matched periodontal defects underwent similar contralateral surgical flap procedures after preliminary scaling, polishing and oral hygiene instruction. At the experimental sites, which were selected at random, the flap was closed over metronidazole impregnated collagen as a GTR membrane, the contralateral sites receiving a plain collagen barrier as control. The plaque index (PLI), gingival index (GI), bleeding index (BI), probing pocket depth (PPD) and probing attachment level (PAL) were recorded at baseline, 6, 12 and 26 weeks post-operatively. The bony defects were classified and furcation involvement noted. The clinical parameters were recorded by an examiner, other than the surgeon, who had been previously assessed for accurate reproducibility of measurements and was unaware of the experimental sites. PPD and PAL were measured with a constant pressure probe, localised by a soft stent. Post-operative discomfort was evaluated by means of a questionnaire. PLI, GI and BI were significantly improved compared to baseline for both test and control sites at 6, 12 and 26 weeks post surgery (p < 0.001) but there was no significant difference between these sites (p > 0.05). There was a reduction in PPD at 6 weeks which was significant at 12 and 26 weeks post-operatively (p < 0.001) for both test and control sites, but no difference between these sites was evident (p > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Guided tissue regeneration in human furcation defects after using a biodegradable barrier: a multi-center feasibility study

This multi-center study evaluated guided tissue regeneration (GTR) in Class II furcation defects using a polylactic acid biodegradable barrier in 29 patients with mandibular and maxillary molar defects. Following an initial hygienic phase, surgical flaps were elevated, and the sites scaled and root planed. Furcation defect perimeter was measured and a customized barrier (thickness 600 to 750 mu) was applied to cover the defect. Barriers adhered directly to tooth and bone. At baseline, sites were measured for probing depth (PD) (6.0 +/- 0.2 [SE] mm), gingival margin location (GML) (-0.2 +/- 0.2 mm), and attachment level in both vertical (AL-V) (6.2 +/- 0.2 mm) and horizontal (AL-H) (5.4 +/- 0.2 mm) directions. After the surgical procedure, there was good compatibility between the gingival tissues and barrier material. Clinically, barriers fragmented and became displaced in 3 to 6 weeks. Substantial granulation tissue was sometimes present between barrier and root surfaces. Comprehensive periodontal examination parameters were measured 3, 4, 6, 9, and 12 months after baseline. A repeated measures ANOVA was used to evaluate changes from baseline. At 6 and 12 months postsurgery, GML was close to the presurgical level (-0.5 +/- 0.2 mm). There was clinically and statistically significant improvement in all other parameters: mean PD reduction (2.2 mm), AL-V gain (1.7 mm), and AL-H gain (2.5 mm). These results indicated favorable clinical regenerative outcomes after using this barrier material in Class II furcation defects in humans.

Treatment of mandibular class III periodontal furcation defects. Coronally positioned flaps with and without expanded polytetrafluoroethylene membranes

Twenty-six mandibular class III furcation defects were treated in 26 subjects using a regenerative therapy that included citric acid root conditioning, placement of freeze-dried decalcified bone allograft and coronally positioned flaps secured by crown-attached sutures. In addition to this therapy, expanded polytetrafluoroethylene (ePTFE) membranes were placed in 14 of the 26 defects. The effect of these therapies was evaluated after 52 to 60 weeks through a series of soft and hard tissue probing measurements including residual furcation classification. For both treatments, mean improvements were observed for furcal probing attachment levels, furcal bone levels, and defect volumes. However, only a few of these through-and-through defects had become closed as judged by a panel of 3 independent examiners. Four defects in each of the 2 treatment groups had changed from Class III to Class I/II or Class II/II evaluated with the soft tissue in place. One defect treated without membrane and 3 defects treated with membranes had changed from Class III to Class II as recorded after reflection of the soft tissues at re-entry. Little difference was observed between defects treated with and without membranes. Further studies with larger sample sizes and longer observation times are needed to fully evaluate these regenerative procedures and their potential for healing Class III furcation defects.

Clinical evaluation of HTR polymer bone replacement grafts in human mandibular Class II molar furcations

A biocompatible microporous composite of PMMA (poly-methyl-methacrylate), PHEMA (poly-hydroxyl-ethyl-methacrylate), and calcium hydroxide (HTR) or autogenous osseous coagulum (AOC) bone replacement grafts were evaluated in 15 pairs of mandibular molar Class II furcations in 9 patients. Following initial preparation, full thickness flaps were raised to gain access to the furcations; mechanical hand and ultrasonic root and defect debridement and chemical (tetracycline) root preparation were performed; paired furcations in each patient were randomly grafted with either HTR or AOC; and the host flaps replaced or slightly coronally positioned. Weekly, then monthly, deplaquing was performed until surgical re-entry at 6 to 12 months. Both treatments improved the clinical status of the treated furcations. Direct clinical measurements demonstrated essentially equivalent clinical results with both bone replacement graft materials related to most hard and soft tissue changes in the furcations. Differences in favor of HTR were found for horizontal residual furcation depth (2.4 mm vs. 3.9 mm), horizontal furcation fill (1.9 mm vs. 0.8 mm), and percent horizontal furcation fill (44.4% vs. 17.1%) (all P < or = 0.05 paired t test). These favorable results with HTR polymer are similar to several reports with other graft materials and with GTR barriers, and suggest that HTR polymer may be a useful therapeutic adjunct in the clinical management of grade II mandibular molar furcations.

Treatment of furcation defects. Guided tissue regeneration versus coronally positioned flap in mandibular molars; a pilot study

The present study was designed to compare the healing results after treatment of buccal class II furcation defects in mandibular molars utilizing guided tissue regeneration (GTR) technique or coronally positioned flap (CPF) technique. The patient sample consisted of 8 subjects with 18 bilateral furcation defects in mandibular molars. At baseline, 6 and 12 months postoperatively assessments of plaque index, gingival index, probing pocket depths, probing attachment level and bleeding on probing were recorded. Radiographic assessment was performed using conventional radiographs and subtraction images at baseline and 12 months postoperatively. The furcation defects were randomly assigned in each patient to either the GTR or the CPF technique. 12 months postoperatively, there was a statistically significant reduction in probing pocket depths in the GTR treated teeth and a tendency to gain of probing attachment levels 6 months postoperatively. The CPF group showed a statistically significant reduction of probing pocket depths at 6 months and a tendency to reduction after 12 months. The radiological assessment demonstrated gain of interradicular bone tissue in 2 furcation defects of the GTR group. Gain of bone tissue could not be demonstrated in the CPF group. No statistically significant differences were observed between the 2 treatment modalities.

Expanded polytetrafluoroethylene membranes and connective tissue grafts support bone regeneration for closing mandibular Class II furcations

Twenty-four mandibular buccal Class II furcation lesions in 12 subjects were treated with reconstructive periodontal therapy including citric acid root treatment and replaced flap surgery. Twelve (12) of the lesions received expanded polytetrafluoroethylene (ePTFE) membranes to cover the furcation entrance (ePTFE group) whereas the remaining 12 lesions received a connective tissue graft over the furcation (CTG group). Clinical assessments, including probing depth, probing attachment level, location of gingival margin, direct bone probing, and defect volume, were taken at baseline and at 12 months reentry. In the ePTFE group 30% of the defect volume filled with bone; 36% of the defects exhibited complete bone closure. In the CTG group 19% of the defect volume filled with bone and 18% of these defects exhibited complete bone closure. There were no meaningful clinical differences between treatment groups except in horizontal probing depth change (P < or = 0.05). This study suggests that connective tissue grafts and ePTFE membranes have comparable potential in supporting bone regeneration in mandibular Class II furcation lesions. Further clinical trials with larger numbers of patients and a longer evaluation period are needed to fully compare these procedures.

Periodontal therapy: prospects for the future

Prior to the 1950s, periodontitis was treated mostly by tooth exfoliation or extraction, and that is still the predominant treatment for most of the world's populations today. Debridement of the root surface by scaling and root planning came into relatively common use in the first half of the present century and has become the central feature held in common by all currently-used forms of periodontal therapy. Until the 1980s, the most commonly-used treatment consisted of scaling and root planing, followed by resective surgery aimed at achieving zero pocket depth. During the 1980s, data were obtained demonstrating that the thoroughness of root debridement and subgingival infection control, not the presence or absence or periodontal pockets, is the major determinant of successful periodontal therapy, and non-surgical therapy became a commonly-used treatment. Neither resective surgery nor non-surgical therapy results in significant regeneration of periodontal attachment. With the realization that periodontitis is an infectious process, the use of antibiotics and other anti-infective agents came into common use as adjuncts to other standard therapies. An understanding of the pathways by which the soft and calcified tissues of the periodontium are destroyed has led to the likelihood of widespread future use of the non-steroidal, anti-inflammatory family of drugs to suppress alveolar bone destruction by blocking prostaglandin production, and to the use of chemically-modified tetracyclines that chelate divalent cations and thereby block tissue destruction by the metalloproteinases. Recent data clearly show that regeneration of the previously-destroyed periodontal attachment tissues is biologically possible, and regeneration has become the goal of therapy for the 1990s. Use of osteoconductive and osteoinductive graft materials can, under favorable conditions, induce roughly 60% to 70% regeneration of bone lesion height or volume with concomitant improvement in the clinical conditions. Regeneration by grafting may be further enhanced by use of barrier membranes that exclude gingival fibroblasts and epithelium from the healing site. Still further enhancement seems to be possible by local application of various growth factors, although studies in this important area are now only in their infancy. The future of periodontal therapy is exceedingly bright.(ABSTRACT TRUNCATED AT 400 WORDS)

Treatment of periodontal furcation defects. Coronally positioned flap with or without citric acid root conditioning in class II defects

A total of 27 mandibular, buccal class II furcation defects were treated in 16 subjects using a coronally positioned flap procedure, with or without citric acid conditioning of the root surfaces. The effect of the therapies was evaluated from a series of soft and hard tissue measurements. Mean improvements were slightly greater for acid treated than for non-acid treated defects. However, none of the mean differences reached statistical significance, indicating that citric acid conditioning may not be a necessary part of the regenerative, coronally positioned flap procedure in mandibular furcations.

Clinical human comparison of expanded polytetrafluoroethylene barrier membrane and freeze-dried dura mater allografts for guided tissue regeneration of lost periodontal support. I. Mandibular molar Class II furcations

The response of mandibular Class II facial furcations to guided tissue regeneration treatment with expanded polytetrafluoroethylene barrier membrane (e-PTFE) or freeze-dried dura mater allograft (FDDMA) barriers was evaluated in 11 pairs of molars in 11 patients. Following initial preparation, full thickness flaps were raised in the area being treated, the bone and furcation defects debrided of granulomatous tissue, and the involved root surfaces mechanically and chemically prepared. By random allocation, e-PTFE or FDDMA barriers were fitted over the furcations, secured in place, and the host flap repositioned or coronally positioned. Postsurgical deplaquing was performed every 10 days leading up to e-PTFE removal at about 6 weeks (the resorbable FDDMA did not require removal). Continuing supportive periodontal therapy was provided until surgical re-entry at one year for documentation and any further necessary treatment. Direct clinical measurements demonstrated essentially similar clinical results with both barrier materials for bone and soft tissue changes (few statistically or clinically significant differences). Exceptions were the amount of horizontal furcation fill and the change in the width of the keratinized gingiva, both of which were better with FDDMA (P less than 0.05). Improvements in open probing attachment levels observed at the time of e-PTFE removal were lost over the intervening months, more so for the vertical than the horizontal component of the furcation lesion. Intrapatient comparisons suggested better horizontal furcation responses with FDDMA. The findings of this study suggest equal clinical results with e-PTFE and FDDMA barriers utilizing the GTR technique. These results in Class II mandibular furcations are less favorable than those reported by others. Barrier techniques to handicap the race between different tissues of the periodontal complex appear to be of some clinical benefit and deserve further evaluation.

Human suprabony healing responses following root demineralization and coronal flap anchorage. Histologic responses in 7 sites

6 suprabony pockets in 2 adult patients were treated with debridement and citric acid root demineralization. Following these procedures, coronal positioning of the marginal flaps was performed at 2 sites. At 4 sites, the marginal flaps were sutured coronally using orthodontic brackets as anchors. At 1 additional site, root debridement only was performed and the margin was placed at about crestal level. Prior to root planing, all roots were notched both at the level of the gingival margin and the most apically positioned calculus. Blocks were harvested 7 and 18 weeks postsurgery and prepared for histologic analysis. Clinical results showed a gain in probing attachment in both coronally positioned sites (average = 1.8 mm) and coronally anchored sites (average = 4.5 mm). The additional debrided-only site showed a gain in probing attachment of 0.1 mm. Histologically, new cementum with functionally inserted fibers was seen within the calculus notch in all coronally anchored sites. This new attachment was associated with crestal osteogenesis. In the 2 coronally positioned and root demineralized sites, new attachment was seen within the calculus notch in 1 out of the 2 specimens evaluated. Within the limits of the evidence presented, coronal anchorage of flaps enhanced probing attachment and new attachment when used in conjunction with root demineralization.

Report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

Subjects of the past decade in the dental literature are reflected in this year's Committee report. We note the decrease in the prevalence of caries, the influence of dental implants, the advancements in dental materials, and the continued efforts to control adhesive events in the oral cavity. This year we included comments from and about many significant review articles published this past year. The Committee continues to be concerned about the quality of some of the work reported and the quality of the reporting. We have attempted to select the distinguished work, that which provides new information to our profession. The subjects covered include pulp biology, caries prevention, periodontics, implants, craniomandibular function and dysfunction, occlusion, and dental materials.

Histologic healing responses in human vertical lesions following the use of osseous allografts and barrier membranes

4 vertical lesions at 3 teeth in 2 volunteer adults with severe periodontitis were treated by open surgical debridement, osseous allografts and barrier membranes. Roots were notched at both gingival margins and the deepest visible calculus and flaps were sutured coronally. Patients were placed on 0.12% chlorhexidine gluconate 2x daily post-surgery, and blocks were harvested 5 to 6 weeks after surgery. No abnormal clinical responses were noted during the observation period. In the 4 sites, the average preoperative pocket depth was 9.4 mm; the post-operative pocket depth averaged 4.9 mm, recession averaged 0.9 mm and gain in clinical closure averaged 3.6 mm. Histologically, new cementum measured coronally-apically at the treated sites varied from 0.0 mm to 1.7 mm, with an average of 1.1 mm. Osseous remodelling and crestal osteogenesis were seen in association with cementogenesis. The newly deposited cementum showed insertion of functional oriented fibers. New attachment was present within 2 out of 4 calculus notches in this sample.

Clinical effects of root debridement in molar and non-molar teeth. A 2-year follow-up

12 patients were studied longitudinally to monitor the effects of basic periodontal therapy in molar and non-molar teeth. Periodontal sites were grouped into molar furcation sites, molar flat-surface sites and non-molar sites. Clinical measurements were taken at baseline and directly followed by full mouth root debridement. Subsequently, measurements were taken every 3rd month until 24 months. At each of these appointments, the patients were monitored for their oral hygiene performance and given supragingival prophylaxis. The mean results indicated that initially moderately deep and deep molar furcation sites responded less favorably to therapy compared to non-molar sites and molar flat-surface sites of similar probing depth. Initial improvements in probing measurements for moderately deep and deep molar furcation sites were limited and also tended to revert during the observation interval. Identification of individual sites with probing attachment loss disclosed that 25% of molar furcation sites lost probing attachment as compared to 7% for non-molar sites and 10% for molar flat-surface sites. These results corroborate previous findings and call for additional or alternative treatment regimens for periodontal furcation pockets.