Treatment of intrabony defects with collagen membrane barriers. Case reports

Effect of cross-linked vs non-cross-linked collagen membranes on bone: A systematic review

The aim of this study was to conduct a systematic review to compare the clinical outcomes of two different resorbable collagen membranes in terms of regenerated bone volume, postoperative complications and membrane degradation during bone regeneration procedures. Randomized controlled trials (RCT) or controlled trials (CT) that compared both techniques were reviewed on four electronic databases up to December 2015, a manual search was performed on the bibliography of the collected articles and the authors were contacted for additional references if undetected on the electronic and manual search. Membrane exposure was evaluated as a dichotomous outcome and the statistical unit was the membrane. The results were presented as relative risk (RR) with a 95% confidence interval. Eight RCTs and one CT were included in this study. The majority of the studies depicted a bone augmentation area, which ranged from 46.15% to 94.6% for the non-cross-link membranes and from 44% to 92.6% for the cross-link membranes at the 4-6 month re-entry surgery. From a total of 289 patients, a forest plot concerning the membrane exposure was constructed using the obtained RR of the included studies. The overall RR was 1.43 (95% CI: 0.85-2.39) with no statistically significant differences between the two groups, although with a marginal tendency towards higher exposure in the cross-link membrane group. This systematic review suggests the different membranes present themselves as appropriate for bone regeneration procedures, although cross-link membranes present higher rates of postoperative complications. However, more RCT with higher sample sizes are needed to evaluate the different membranes. The suggested lack of clinical differences between the compared membranes suggest that further cost-benefit ratio, tissue integration and postoperative complication oriented studies should be performed so that clinicians can take a patient-centred, evidence-based decision.

A multilevel modelling solution to mathematical coupling

Owing to mathematical coupling, statistical analyses relating change to baseline values using correlation or regression are erroneous, where the statistical procedure of testing the null hypothesis becomes invalid. Alternatives, such as Oldham’s method and the variance ratio test, have been advocated, although these are limited in the presence of measurement errors with non-constant variance. Furthermore, such methods prohibit the consideration of additional covariates (e.g., treatment group within trials) or confounders (e.g., age and gender). This study illustrates the more sophisticated approach of multilevel modelling (MLM) which overcomes these limitations and provides a comprehensive solution to the analysis of change with respect to baseline values. Although mathematical coupling is widespread throughout applied research, one particular area where several studies have suggested a strong relationship between baseline disease severity and treatment effect is guided tissue regeneration (GTR) within dental research. For illustration, we use GTR studies where the original data were found to be available in the literature for reanalysis. We contrast the results from an MLM approach and Oldham’s method with the standard (incorrect) approach that suffers from mathematical coupling. MLM provides a robust solution when relating change to baseline and is capable of simultaneously dealing with complex error structures and additional covariates and/or potential confounders.

Surgical Treatment of Periodontal Intrabony Defects with Calcium Sulphate in Combination with Beta-Tricalcium Phosphate: Clinical Observations Two Years Post-Surgery

The study was designed to evaluate the clinical outcome of a composite material, beta-tricalcium phosphate in combination with calcium sulphate, in the treatment of periodontal intrabony defects. The combination of these materials is believed to aid in guided tissue regeneration owing to their properties. A total of 47 teeth with intrabony defects in 26 periodontitis patients were treated with Fortoss® Vital (Biocomposites, Staffordshire, UK). Clinical parameters were evaluated which included changes in probing depth, clinical attachment level/loss and gingival recession at the baseline and 2 years postoperatively. The mean differences in measurements between the baseline and 2 years postoperatively were a reduction of 2.07±1.14 mm (p=0.000) in case of probing depth and a gain of 1.93±1.36 mm (p=0.000) in clinical attachment level; but an increase of 0.14±0.73 mm (p=0.571) in gingival recession. The study results show that the treatment with a combination of beta tricalcium phosphate and calcium sulphate led to a significantly favorable clinical improvement in periodontal intrabony defects 2 years after the surgery.

The Role of Two Different Collagen Membranes for Dehiscence Defect Around Implants in Humans

The aim of this study was to elucidate the role of 2 types of collagen membranes (cross-linked vs noncross-linked) used in conjunction with autogenous or allogenic bone followed by xenogeneic bone particles for dehiscence defect around implants in humans. Experimental groups were divided into 2 groups: Group CL (cross-linked, Ossix Plus, n = 24 implants, 16 patients) and Group NCL (noncross-linked, Bio-Gide, n = 25 implants, 18 patients). At the time of implant insertion and uncovery surgery, measurements of the dehiscence bony height, width, and surface area were made. Before applying the membrane to defects, guided bone regeneration was performed. Because it is difficult to measure the degree of exposure, early exposed cases were excluded from the result analysis. The mean percentage gain of the dehiscence defect and the mean marginal bone reduction value of follow-up radiograph did not show statistically significant differences between the 2 groups. Both membranes exhibited satisfactory results on dehiscence defects. As a result, our authors concluded the success of guided bone regeneration was performed simultaneously for dehiscence defects around the implant, regardless whether collagen membranes were cross-linked or noncross-linked.

Biomaterials in periodontal osseous defects

INTRODUCTION

Osseous defects in periodontal diseases require osseous grafts and guided tissue regeneration (GTR) using barrier membranes. The present study was undertaken with the objectives to clinically evaluate the osteogenic potential of hydroxyapatite (HA), cissus quadrangularis (CQ), and oxidized cellulose membrane (OCM) and compare with normal bone healing.

MATERIALS AND METHODS

Twenty subjects with periodontitis in the age group ranging from 20 years to 40 years were selected from our outpatient department on the basis of presence of deep periodontal pockets, clinical probing depth ≥5 mm, vertical osseous defects obvious on radiograph and two- or three-walled involvement seen on surgical exposure. Infrabony defects were randomly divided into four groups on the basis of treatment to be executed, such that each group comprised 5 defects. Group I was control, II received HA, III received CQ and IV received OCM. Probing depth and attachment level were measured at regular months after surgery. Defects were re-exposed using crevicular incisions at 6 months.

RESULTS

There was gradual reduction in the mean probing pocket depth in all groups, but highly significant in the site treated with HA. Gain in attachment level was higher in sites treated with HA, 3.2 mm at 6 months.

CONCLUSION

Hydroxyapatite and OCM showed good reduction in pocket depth, attachment level gain and osseous defect fill. Further study should be conducted by using a combination of HA and OCM in periodontal osseous defects with growth factors and stem cells.

Ammonium bicarbonate as porogen to make tetracycline-loaded porous bioresorbable membranes for dental guided tissue regeneration: failure due to tetracycline instability

The goal of this work was to manufacture a bioresorbable porous membrane aimed at both promoting osseous regeneration in oral surgery and delivering an antibiotic drug locally. The selected design consisted of a porous poly (D,L-lactic acid) matrix having a closed smooth face on one side to prevent inner migration of conjunctive and epithelial cells, and the rest of the membrane presenting open porosity to allow in-growth of osseous neotissue. The antibiotic drug was tetracycline because of its large antibacterial spectrum and its osteogenetic activity. Solvent casting/particulate leaching and gas foaming/salt leaching methods were selected to create the porosity, and ammonium bicarbonate was selected as thermosensitive water-soluble porogen because other studies reported that sodium chloride was difficult to remove totally. One-side-skinned, porous permeable membranes were successfully obtained. However, deleterious alterations of the drug were observed that were assigned to the basicity of the porogen, thus precluding any practical use in vivo.

Chitosan as a barrier membrane material in periodontal tissue regeneration

Periodontal regeneration is defined as regeneration of the tooth-supporting tissues including cementum, periodontal ligament, and alveolar bone. Guided tissue regeneration (GTR) has been demonstrated to be an effective technique to achieve periodontal regeneration. In the GTR procedures, various kinds of membranes play important roles. Chitosan, a deacetylated derivative of chitin, is biocompatible, biodegradable, and antimicrobial. It acts as hydrating agent and possesses tissue healing and osteoinducing effect. Chitosan can be easily processed into membranes, gels, nanofibers, beads, nanoparticles, scaffolds, and sponges forms and can be used in drug delivery systems. Here, we review the bioproperties of chitosan and report the progress of application of chitosan as membranes in GTR and guided bone regeneration (GBR), which indicates that chitosan could be a good substrate candidate as the materials for the GTR/GBR membranes.

Healing of intrabony defects following treatment with an oily calcium hydroxide suspension (Osteoinductal). A controlled clinical study

The purpose of the present clinical study was to evaluate the healing of deep intrabony defects following the application of an oily calcium hydroxide suspension (OCHS). Thirty patients suffering from chronic periodontitis, each of whom displayed one intrabony defect, were randomly treated with access flap surgery (AFS) and the application of OCHS (test) or with AFS alone (control). The following clinical parameters were recorded at baseline and at 6 months after therapy: plaque index, gingival index, bleeding on probing, probing depth (PD), gingival recession, and clinical attachment level (CAL). No differences in any of the investigated parameters were observed at baseline between the two groups. At 6 months after therapy, the test group showed a reduction in mean PD from 7.7+/-1.5 to 2.9+/-0.9 mm (P<0.001) and a change in mean CAL from 9.6+/-2.1 to 5.5+/-2.5 mm (P<0.001). In the control group, the mean PD was reduced from 6.9+/-0.9 to 3.7+/-0.9 mm (P<0.001) and the mean CAL changed from 8.5+/-2.5 to 6.4+/-2.7 mm (P<0.001). OCHS resulted in statistically significant higher PD reductions (P<0.01) and CAL gains (P<0.05) than AFS alone. Within the limits of the present study, it can be concluded that: (1) at 6 months after surgery both therapies resulted in statistically significant PD reductions and CAL gains and (2) treatment with OCHS resulted in statistically significant higher CAL gains than treatment with AFS alone.

The relationship between baseline value and its change: problems in categorization and the proposal of a new method

Oral health researchers have shown great interest in the relationship between the initial status of diseases and subsequent changes following treatment. Two main approaches have been adopted to provide evidence of a positive association between baseline values and their changes following treatment. One approach is to use correlation or regression to test the relationship between baseline measurements and subsequent change (correlation/regression approach). The second approach is to categorize the lesions into subgroups, according to threshold values, and subsequently compare the treatment effects across the two (or more) subgroups (categorization approach). However, the correlation/regression approach suffers a methodological weakness known as mathematical coupling. Consequently, the statistical procedure of testing the null hypothesis becomes inappropriate. Categorization seems to avoid the problem of mathematical coupling, although it still suffers regression to the mean. We show, first, how the appropriate null hypothesis may be established to analyze the relationship between baseline values and change in the correlation approach and, second, we use computer simulations to investigate the impact of regression to the mean on the significance testing of the differences in the average treatment effects (or average baseline values) in the categorization approach. Data available from previous literature are reanalyzed by testing the appropriate null hypotheses and the results are compared to those from testing the usual (incorrect) null hypothesis. The results indicate that both the correlation and categorization approaches can give rise to misleading conclusions and that more appropriate methods, such as Oldham's method and our new approach of deriving the correct null hypothesis, should be adopted.

Guided tissue regeneration in intrabony periodontal defects following treatment with two bioabsorbable membranes in combination with bovine bone mineral graft. A clinical and radiographic study

AIM

Comparison of two bioabsorbable barriers (collagen and polylactic acid (PLA) membranes) combined with a bovine bone mineral (BBM) graft, with an access flap procedure (AFP) alone for treating intrabony defects.

MATERIAL AND METHODS

Thirty-four subjects participated in this prospective, controlled clinical trial. Baseline clinical examination (probing depth (PD), clinical attachment level (CAL)) of selected sites was performed 2 months after completion of conservative treatment in conjunction with hard-tissue measurements to ascertain the depth of the defect (cementoenamel junction to the bottom of the defects). After randomly dividing patients into three groups (two membrane groups, one control group), full thickness flaps were elevated and exposed root surfaces planed before filling defects with bone graft and positioning a barrier membrane covering the defect. The control group was treated identically except for the barrier and bone graft placement. Clinical treatment outcomes were finally evaluated 12 months after surgery for changes of PD and CAL. Radiographs at baseline and 12 months were compared using non-standardized digital radiography.

RESULTS

A mean reduction in PD value of 5.08 mm and mean CAL gain of 4.39 mm occurred in the collagen-BBM group. Corresponding values for the PLA-BBM group were 4.72 and 3.71 mm, while access flap procedure (AFP) sites produced values of 2.50 and 2.43 mm. All improvements in clinical parameters were statistically significant (p<0.001) within groups for all variables. Both membranes produced statistically greater PD reduction and CAL gain compared with AFP treatment (p<0.05). Comparison between barrier groups failed to reveal any statistically significant difference in probing pocket depth reduction (p=0.56) or in CAL gain (p=0.34).

CONCLUSION

Placement of the two barrier membranes used in the present study in combination with BBM graft significantly improved clinical and radiographic parameters of deep intrabony pockets and proved superior to access flap alone.

Polymer-assisted regeneration therapy with Atrisorb barriers in human periodontal intrabony defects

AIM

This study compared clinical results of 40 periodontal osseous defects treated by two types of absorbable barrier materials.

MATERIAL AND METHODS

Thirty patients (23 males and seven females) suffering from moderate to advanced periodontitis (with comparable osseous defects) were randomly assigned to receive either Atrisorb barrier (n = 22; group A) or Resolut XT barrier (n = 18; group B) therapy. Periodontal phase I treatment and oral hygiene instruction were performed before periodontal surgery. Papillary preservation, partial thickness flap, citric acid root conditioning, and decortication procedures were applied during the operation. Bone defects were filled with demineralized freeze-dried bone allograft and minocycline mixture (4:1 ratio). Postoperative care included 0.10% chlorhexidine rinse daily and antibiotic medication for 2 weeks. Clinical assessments including probing depth (PD), clinical attachment level (CAL), gingival recession (GR), plaque index (PII), gingival index (GI), and radiographic examinations were taken at the baseline, preoperatively and at 3 and 6 months after regenerative surgery.

RESULTS

Six months following therapy, both Atrisorb and Resolut XT groups had achieved comparable clinical improvement in pocket reduction (3.9 versus 4.4 mm), attachment tissue gain (clinical attachment gain; 3.5 versus 3.6 mm), and reduction in the GI and in the PII. Within-group comparisons showed significant attachment gain and pocket reduction between baseline data and those at both 3 and 6 months postoperatively (p < 0.01). There were no statistically significant differences in any measured data between groups A and B.

CONCLUSIONS

The results of this study indicate that a comparable and favorable regeneration of periodontal defects can be achieved with both Atrisorb and Resolut XT barriers. Further long-term study and histologic observations of tissue healing are needed to evaluate whether Atrisorb is promising for clinical use.

Comparison of Porous and Non-Porous Teflon Membranes Plus a Xenograft in the Treatment of Vertical Osseous Defects: A Clinical Reentry Study

BACKGROUND

The primary aim of this 9-month randomized, controlled, blinded, clinical reentry study was to compare the regenerative effects of a nonporous polytetrafluoroethylene (NP) periodontal membrane to a porous expanded polytetrafluoroethylene (P) periodontal membrane in the treatment of vertical osseous defects.

METHODS

Twenty-four patients, 11 males and 13 females, age 24 to 74 (mean 50.5 +/- 13.1) provided one site with an intraosseous defect > or = 4 mm and were divided equally and randomly into two groups. Following debridement both groups were grafted with a bovine-derived xenograft coated with a synthetic cell-binding peptide; then the test group received an NP membrane and the control group received a P membrane. All defects were reentered after 9 months. Measurements were performed by a masked examiner.

RESULTS

There were no statistically significant differences (P>0.05) between NP and P groups for any open or closed probing measurement at any time. Similar open initial defect depth for the NP group and P groups (4.8 versus 5.0 mm) demonstrated identical 9-month defect fill of 2.8 mm (57%) for both groups. A difference in crestal resorption for the NP compared to the P group (0.4 versus 0.8 mm) accounted for the difference in mean percent defect resolution, which was 67% for NP compared to 72% for the P group. Overall, nine (75%) of the NP group defects and eight (67%) of the P group defects showed more than 50% defect fill.

CONCLUSION

Treatment of vertical osseous defects with nonporous or porous polytetrafluoroethylene membranes in combination with a xenograft resulted in statistically significant improvement in open and closed probing measurements, with no significant difference between treatment groups.

Guided tissue regeneration in human Class II furcation defects using a diphenylphosphorylazide-cross-linked collagen membrane: a consecutive case series

BACKGROUND

Several bioabsorbable collagen membranes are either currently available or under investigation for use in guided tissue regeneration (GTR) procedures. The aim of this 12-month reentry study was to evaluate a diphenylphosphorylazide (DPPA)-cross-linked bovine type I collagen membrane in the healing of mandibular Class II furcation defects. The DPPA technique prevents the inclusion of foreign cytotoxic cross-linking substances in the reticulated molecules, thus providing a more biocompatible product.

METHODS

Forty non-smoking periodontally compromised adult subjects volunteered for this study, and one defect was randomly selected in each patient. At baseline, plaque index (PI), gingival index (GI), probing depth (PD), gingival margin location (GML), clinical attachment level (CAL), and width of the attached gingiva (AG) were measured. Intrasurgical hard tissue measurements consisted of the vertical open probing attachment level (V-OPAL) and horizontal open probing attachment level (H-OPAL), as well as furcation entrance width (FW) and height (FH) and subclassification of defects according to vertical bone loss. All soft tissue measurements were repeated 12 months after membrane placement using conservative flap reentry surgeries; hard tissue parameters were also assessed at this time.

RESULTS

DPPA-cross-linked collagen membranes demonstrated good handling characteristics, and no postoperative adverse tissue reactions or clinically detectable localized allergic responses were observed. GI and PI remained low during the entire study period. When the one year reentry values were compared to the baseline measurements, a significant reduction in PD (1.9 +/- 1.4), FW (2.1 +/- 1.7), FH (2.9 +/- 1.6), and gain in CAL (1.7 +/- 1.5), V-OPAL (2.1 +/- 1.9), and H-OPAL (4.7 +/- 1.4) were observed (P < or = 0.05). However, there were no significant differences in GML or AG. Hard tissue improvements resulted in the complete closure of 30% (12) of the defects, and transformation of 67.5% (27) of the defects to Class I, while one defect remained a Class II (2.5%).

CONCLUSIONS

Based on this 12-month clinical reentry study, a DPPA-cross-linked collagen membrane could be beneficial in GTR treatment of Class II mandibular furcation involvements, both in terms of soft and hard tissue improvements.

Platelet-rich plasma and bovine porous bone mineral combined with guided tissue regeneration in the treatment of intrabony defects in humans

BACKGROUND

A combination of platelet-rich plasma (PRP), bovine porous bone mineral (BPBM) and guided tissue regeneration (GTR) has been shown to be effective in promoting clinical signs of periodontal regeneration in intrabony defects. As an initial attempt to clarify the role played by each of the three treatment components, this study was performed to compare the clinical effectiveness of two regenerative techniques for intrabony defects in humans: a combination of PRP/BPBM/GTR vs. GTR.

MATERIAL AND METHODS

Eighteen patients participated in the study. Using a split-mouth design, interproximal bony defects were surgically treated with either an absorbable membrane made of polylactic acid for GTR or a combination of PRP/BPBM/GTR. Changes in pocket depth, attachment level and defect fill as revealed by 6-month reentry surgeries were evaluated.

RESULTS

Both treatment modalities resulted in significant pocket depth reduction and clinical attachment gain as compared to baseline values. Pocket depth reduction was 4.98 +/- 0.96 mm on buccal and 4.93 +/- 0.92 mm on lingual sites of the PRP/BPBM/GTR group and 3.62 +/- 0.81 mm on buccal and 3.54 +/- 0.88 mm on lingual sites of the GTR group. The gain in clinical attachment observed was 4.37 +/- 1.31 mm on buccal and 4.28 +/- 1.33 mm on lingual sites of the PRP/BPBM/GTR group and 2.62 +/- 1.23 mm on buccal and 2.44 +/- 1.21 mm on lingual sites of the GTR group. The amount of defect fill observed was 4.78 +/- 1.26 mm on buccal and 4.66 +/- 1.32 mm on lingual sites of the PRP/BPBM/GTR group and 2.31 +/- 0.76 mm on buccal and 2.26 +/- 0.81 mm on lingual sites of the GTR group. All differences between the two groups were statistically significant in favor of the PRP/BPBM/GTR group.

CONCLUSIONS

The results of this study suggest that PRP and BPBM provide an added regenerative effect to GTR in promoting the clinical resolution of intrabony defects on patients with severe periodontitis.

Combined periodontal regenerative technique in human intrabony defects by collagen membranes and anorganic bovine bone. A controlled clinical study

BACKGROUND

Combined periodontal regenerative technique (CPRT) is a surgical procedure that combines the use of barrier membranes with a filling material in the treatment of periodontal defects. The effectiveness of CPRT has been evaluated in many studies in comparison to GTR with membranes alone, but conflicting results have been obtained by different clinicians, particularly in the treatment of intrabony defects. The aim of the present study was to compare CPRT to GTR with collagen membranes in the treatment of human intrabony defects characterized by a relevant 1-wall component.

METHODS

Thirty-four (34) healthy, non-smoking patients affected by moderate to severe chronic periodontitis participated in this study. Each patient had good oral hygiene and at least 1 radiographically detectable intrabony defect > or = 4 mm, with a 1-wall component of at least 50% of the defect, involving 2 tooth surfaces or more with a probing depth (PD) > or = 6 mm. Seventeen (17) subjects were randomly assigned to the test group and underwent CPRT by anorganic bovine bone and a collagen membrane, and 17 randomly assigned to the control group who received GTR with a collagen membrane alone. Pre- and post-therapy clinical parameters (probing depth [PD]; clinical attachment level [CAL]; gingival recession [GR]) and intrasurgical parameters (depth of intraosseous component [IOC]; level of the alveolar crest [ACL]) were compared between test and control groups 1 year after treatment. Vertical bone gain (VBG) from the base of the defect to the cemento-enamel junction was also evaluated in both groups.

RESULTS

At the 1-year examination, clinical and intrasurgical parameters showed statistically significant changes within each experimental group from baseline. A statistically greater CAL gain was reported in the test group (P<0.05), whereas the control group exhibited more GR and alveolar crest resorption at a statistically significant level (P<0.01). VBG was significantly greater (P<0.01) at test sites (5.23 +/- 1.30 mm) compared to controls (3.82 +/- 1.28 mm).

CONCLUSIONS

The results suggest that the use of CPRT may be preferred when bioabsorbable membranes are used to treat intrabony defects characterized by unfavorable architecture.

The simplified papilla preservation flap in the regenerative treatment of deep intrabony defects: clinical outcomes and postoperative morbidity

BACKGROUND

The aims of the present multi-center, randomized, controlled clinical trial were: 1) to compare the efficacy of the simplified papilla preservation flap with and without a barrier membrane in deep intrabony defects; 2) to evaluate the postoperative morbidity and surgical complications; and 3) to preliminarily test the impact of baseline tooth mobility on clinical outcomes.

METHODS

This parallel group, randomized, multi-center, controlled clinical trial involved 112 patients in 8 periodontal practices in 4 countries. A deep intrabony defect in each patient was accessed with the simplified papilla preservation flap. In the test defects, a bioabsorbable membrane was positioned. Patients' experiences with the surgical procedure and postoperative period were evaluated with a questionnaire. Clinical outcomes included clinical attachment level (CAL) and probing depth (PD) changes.

RESULTS

Complete observations were available for 55 test and 54 control defects. CAL gains at 1 year were 3.5 +/- 2.1 mm in the guided tissue regeneration (GTR) group and 2.6 +/- 1.8 mm in the control group (P = 0.0117). CAL gains > or = 4 mm were observed in 50.9% of GTR sites and 33.3% of control sites. A significant center effect of 2.1 mm was observed (P= 0.01). Initial PD (P= 0.01) and baseline tooth mobility (P= 0.036) were significant covariates. During the procedure, 30.4% of test and 28.6% of controls reported feeling moderate pain, and subjects estimated the hardship of the procedure at 24 +/- 25 visual analog scale (VAS) units in the test group, and at 22 +/- 23 VAS in controls. In terms of the investigated outcomes, differences between test and control groups were not statistically significant. Among the postoperative complications, edema was most prevalent at week 1, and more frequently associated with the test treatment (P= 0.01). In the test group, 53.6% of membranes were exposed at week 3.

CONCLUSIONS

The present study further supports the added benefits of guided tissue regeneration with respect to access flap alone in the treatment of deep intrabony defects, as well as the general efficacy of GTR in different clinical settings. Furthermore, our study indicates a possible influence of baseline tooth mobility on clinical outcomes.

Subperiosteal and intraosseous connective tissue grafts for pocket reduction: a 9- to 13-year retrospective case series report

BACKGROUND

Recent histological evidence has documented that grafted palatal connective tissue is capable of forming a new attachment to previously exposed roots in the treatment of gingival recession. No clinical studies have tested the ability of connective tissue that has been implanted beneath the periosteum into periodontal osseous defects to reduce probing depth and increase clinical attachment levels. This study reports the long-term clinical effect of subperiosteal and intraosseous connective tissue grafts on deep periodontal pockets.

METHODS

Connective tissue (CT) grafts were placed in 32 periodontal pockets on 27 patients. Grafts were classified into 3 groups. Type I grafts had 50% or more vascular surface contact and were < or = 2.5 mm thick. Type II grafts had 50% or more contact but were > 2.5 mm thick, and Type III grafts had less than 50% vascular contact regardless of thickness. Twelve of 14 Type I sites, 9 of 15 Type II sites, and 3 of 3 Type III sites were analyzed 9 to 13 years following treatment.

RESULTS

Clinical attachment level change differed significantly between the graft types on survivor teeth (P < 0.05): Type III had 2 mm loss (95% confidence interval [CI]: 0.4 to 3.6), while Type II and Type I grafts had a 2.7 mm gain (95% CI: 2.0 to 3.4) and 4.3 mm gain (95% CI: 3.3 to 5.2), respectively. Similar substantial differences were presented for changes in probing depth and recession.

CONCLUSIONS

This long-term (9 to 13 years) retrospective case-series analysis suggests substantial improvements in periodontal clinical measures for Type I CT grafts in deep periodontal pockets. Randomized trials are required to evaluate this promising procedure.

Subperiosteal connective tissue grafts for pocket reduction and preservation of gingival esthetics: a case report

BACKGROUND

Clinical studies and recent histological evidence following mucogingival surgery for the treatment of gingival recession have documented that when closely adapted to a previously exposed root surface, connective tissue is capable of forming a new attachment. Despite these findings, no clinical tests have been conducted to examine the ability of connective tissue to reduce probing depth (PD) and increase clinical attachment levels (CAL) when it is implanted into periodontal osseous defects. The purpose of this paper is to report the clinical results on a patient following 2 subperiosteal connective tissue grafts.

METHODS

Subperiosteal connective tissue grafts were placed in 2 sites of periodontal bone loss and deep pocketing in one patient. Following flap reflection and root preparation, a connective tissue graft 1.5 to 2.0 mm in thickness was draped and sutured over each osseous defect and then completely covered by the external flap.

RESULTS

Ten months following subperiosteal connective tissue grafting, tooth #7 had 4 mm of CAL gain. Tooth #10 had 3 mm of CAL gain 8 months postoperatively. Both teeth had 1 mm gain in gingival recession. Both teeth probed 3 mm postoperatively.

CONCLUSIONS

When connective tissue was grafted into 2 periodontal osseous defects, there were significant reductions in probing depth and gains in CAL. There was minimal postoperative gingival recession. The new clinical attachment gain remained stable for 8 to 10 months following subperiosteal connective tissue grafting.

Evaluation of the effect of tooth vitality on regenerative outcomes in infrabony defects

BACKGROUND, AIMS

This investigation was designed to evaluate the null hypothesis of no differences in GTR outcomes in intrabony defects at vital and successfully root-canal-treated teeth.

METHOD

208 consecutive patients with one intrabony defect each were enrolled. Based on tooth vitality, the treated population was divided at baseline into 2 groups: one with 41 non-vital teeth and the other with 167 vital teeth. The 2 groups were similar in terms of patient and defect characteristics.

RESULTS

A slight unbalance in terms of depth of the intrabony component was observed in the non-vital group compared to the vital group (6.9+/-2.1 mm versus 6.2+/-2.3 mm, p=0.08). All defects were treated with GTR therapy. At 1 year, the non-vital and the vital groups showed a clinical attachment level (CAL) gain of 4.9+/-2.2 mm and of 4.2+/-2 mm, respectively. The difference was statistically significant (p=0.03). To correct for the baseline unbalance in defect depth, data were expressed as a % of clinical attachment level gains with respect to the original intrabony depth of the defect. % CAL gains were 72.8+/-42.2% and 73+/-26.4% for vital and non-vital teeth, respectively: the difference was not statistically significant (p=0.48). Average residual pocket depths were 2.8+/-1 mm in the vital and 2.8+/-0.9 mm in the non-vital group. Tooth vitality was assessed at baseline, at 1-year and at follow-up (5.4+/-2.8 years after surgery): all teeth vital at baseline were still vital at follow-up with the exception of 2 teeth that received endodontic treatment for reconstructive reasons and for caries. At follow-up visit, the difference in CAL with respect to 1-year measurements was -0.9+/-0.8 mm in the vital group and -0.7+/-0.8 mm in the non-vital group, indicating stability of the regenerated attachment at the majority of sites.

CONCLUSIONS

Data from this study demonstrate that root canal treatment does not negatively affect the healing response of deep intrabony defects treated with GTR therapy; furthermore GTR therapy in deep intrabony defects does not negatively influence tooth vitality.

Collagen membranes: a review

Collagen materials have been utilized in medicine and dentistry because of their proven biocompatability and capability of promoting wound healing. For guided tissue regeneration (GTR) procedures, collagen membranes have been shown to be comparable to non-absorbable membranes with regard to probing depth reduction, clinical attachment gain, and percent of bone fill. Although these membranes are absorbable, collagen membranes have been demonstrated to prevent epithelial down-growth along the root surfaces during the early phase of wound healing. The use of grafting material in combination with collagen membranes seems to improve clinical outcomes for furcation, but not intrabony, defects when compared to the use of membranes alone. Recently, collagen materials have also been applied in guided bone regeneration (GBR) and root coverage procedures with comparable success rates to non-absorbable expanded polytetrafluoroethylene (ePTFE) membranes and conventional subepithelial connective tissue grafts, respectively. Long-term clinical trials are still needed to further evaluate the benefits of collagen membranes in periodontal and peri-implant defects. This article will review the rationale for each indication and its related literature, both in vitro and in vivo studies. The properties that make collagen membranes attractive for use in regenerative therapy will be addressed. In addition, varieties of cross-linking techniques utilized to retard the degradation rate of collagen membranes will be discussed.

The Accuracy of Radiographic Methods in Assessing the Outcome of Periodontal Regenerative Therapy

BACKGROUND

The study of regenerative therapy in the periodontal intrabony defect has relied upon surgical re-entry as the gold standard of outcome assessment. The search for a non-invasive method has led to the application of various radiographic techniques in evaluating post-treatment bone fill.

METHODS

The purpose of this study was to determine the ability of 2 forms of radiographic analyses (linear measurement and computer assisted densitometric image analysis, CADIA) to assess postsurgical bone fill as measured at a re-entry procedure. A method that incorporates linear measurements and CADIA (linear-CADIA) was developed and tested as well. Forty-five intrabony defects in 15 patients were treated with open flap debridement, demineralized freeze-dried bone allograft (DFDBA), or a combination of DFDBA and tetracycline. Standardized radiographs were obtained at baseline and at 1-year postsurgery.

RESULTS

A 12-month surgical re-entry provided clinical measurements for post-treatment bone fill. All radiographs were digitally scanned and analyzed on a computer. Fifty-three percent of the defects were excluded from the study due to poor standardization or poor defect quality. Forty percent of all pairs of radiographs were judged to have poor standardization. In the first analysis, standardized images were subtracted and quantitatively analyzed utilizing CADIA. It was found that CADIA had the highest correlation with clinical bone fill when a region of interest (ROI) was examined in the middle portion of the defect. This quantitative evaluation provided very little clinically relevant information regarding actual bone fill. For the second analysis, pre- and post-treatment linear radiographic measurements were obtained. In only 43% of the sites, did linear radiographic measurements determine post-treatment bone fill within 1.0 mm of the clinical measurements. Overall, linear measurements underestimated bone fill by 0.96 mm (+/-1.2). These differences were statistically significant (paired Student t-test, P = 0.0023). A method, which incorporates the use of both CADIA and linear radiographic measurements (linear-CADIA), was tested. The linear-CADIA method underestimated bone fill by 0.26 mm (+/-1.4), but these differences were not statistically significant (paired Student t-test, P = 0.41).

CONCLUSION

Linear radiographic measurements significantly underestimate post-treatment bone fill when compared to re-entry data. The linear-CADIA method provided the highest level of accuracy of the 3 methods tested. This study also emphasizes the importance of developing a consistent method of radiographic standardization.

The effect of postsurgical naproxen and a bioabsorbable membrane on osseous healing in intrabony defects

BACKGROUND

Previous reports in the literature have shown that non-steroidal anti-inflammatory drugs (NSAID) may affect osseous tissues by either stimulating or inhibiting bone formation. This effect can be drug specific and different NSAIDs may produce opposite results. There are also reports showing that NSAIDs inhibit bone loss due to inflammatory disease process. The purpose of this randomized, controlled, blinded, clinical investigation was to determine the effect of a one week course of postsurgical naproxen on the osseous healing in intrabony defects.

METHODS

Twenty-four vertical osseous defects in 24 patients were treated with either a bioabsorbable membrane plus twice daily postsurgical naproxen 500 mg for one week (test or GPN group) or with a polylactide bioabsorbable membrane alone (control or GA group). Twelve patients were included in each group. Treatment was performed on either 2- or 3-wall or combination defects. All measurements were taken from a stent by a calibrated, blinded examiner and open measurements were repeated at the 9-month second stage surgery. Power analysis to determine superiority of naproxen treatment showed that a 12 per group sample size would yield 87% power to detect a 2.0 mm difference and 64% power to detect a 1.5 mm difference.

RESULTS

Open defect measurements from baseline to 9 months showed a statistically significant (P < 0.05) mean defect fill of 1.96 +/- 1.27 mm and 2.04 +/- 1.71 for the GPN and GA groups, respectively. This corresponded to a mean defect fill of 42% and a mean defect resolution of approximately 75% for both groups. The differences between GPN and GA groups were not statistically significant (P > 0.05). Defect fill of > or = 50% was seen in 6 defects (50%) in the GPN group and in 5 defects (42%) in the GA group.

CONCLUSIONS

The administration of postsurgical naproxen failed to produce osseous healing that was statistically superior to that obtained with polylactide bioabsorbable membranes alone.

The use of 2 bioabsorbable barrier membranes in the treatment of interproximal intrabony periodontal defects

BACKGROUND

The use of barrier membranes in the treatment of periodontal defects is well documented. There has been an increase in the use of bioabsorbable materials which do not require a second surgical procedure for removal. However, there are little data evaluating the efficacy of bioabsorbable membranes in the treatment of intrabony defects. The purpose of this investigation was to evaluate the regenerative potential of 2 bioabsorbable barrier membranes without the use of grafting materials in the treatment of interdental intrabony defects.

METHODS

Twenty-three 2- or 3-walled intrabony defects were treated in 19 patients with a mean age of 50.4 years. All had completed nonsurgical treatment and a period of supportive periodontal therapy. The sites were randomly chosen to receive a barrier membrane composed of type I bovine collagen (11) or a copolymer of polylactic acid (PGA/PLA;12). A pressure sensitive disc probe was used to evaluate the following criteria at baseline and re-entry: 1) occlusal surface to the apical depth of probe penetration (OS-DP); 2) occlusal surface to the gingival margin (OS-GM); 3) occlusal surface to the alveolar crest (OS-AC); and 4) occlusal surface to the base of the osseous defect (OS-BD). Full thickness mucoperiosteal flaps were reflected to expose the surgical sites. The defects were debrided of the granulomatous tissue, the root surfaces instrumented and conditioned with 4 one-minute applications of 50 mg/ml of tetracycline. The barrier membranes were adapted to cover the defects and the flaps replaced. The postsurgical healing was uneventful and similar in both treatment modalities.

RESULTS

Twenty-three sites were surgically re-entered 6 months from the time of the initial surgery. The deepest probe depth for each site was used for statistical analysis. There was a mean relative attachment gain of 2.58+/-1.90 mm for the collagen, and 2.77+/-2.13 mm for the copolymer. There was a decrease in probing depth of 3.27+/-1.91 mm and 0.69+/-1.35 mm of recession for the collagen. The PGA/PLA copolymer had 3.55+/-2.47 mm reduction in probe depth and 0.78+/-1.14 mm of recession.

CONCLUSIONS

The data indicated the bioabsorbable collagen and copolymer membranes resulted in comparable results. A larger sample size would be necessary to determine if one membrane was superior to the other.

Treatment of deep and shallow intrabony defects. A multicenter randomized controlled clinical trial

This prospective multicenter intra-individual randomized controlled clinical trial was designed to compare the efficacy of guided tissue regeneration (GTR) with bioresorbable barrier membranes versus access flap surgery, in intrabony defects. 2 similar defects were selected in each of 23 patients and randomly assigned to 1 of the 2 treatments. Surgery consisted of an identical procedure except for the omission of the barrier membrane in the flap control sites. At 1-year, probing pocket depth reductions were 4.3+/-2.3 mm in GTR treated sites and 3.0+/-1.5 mm in the flap control sites (p=0.02, paired t-test). Clinical attachment level (CAL) gains were 3.0+/-1.7 mm in the GTR sites and 1.6+/-1.8 mm in the control sites (p=0.009, paired t-test). A subset analysis, performed according to the initial depth of the intrabony component of the defects (INFRA), indicated that in shallow defects (INFRA < or =3 mm) treated with the access flap alone, CAL gains were 1+/-1.5 mm, while in deep ones (INFRA > or =4 mm) they were consistently greater (1.9+/-1.9 mm). The % CAL gains, calculated as the % of the baseline intrabony component depth, however, were almost identical in the 2 subpopulations (45.8+/-64.7% in shallow and 43.8+/-37.6% in deep defects). Similarly, in the GTR sites, linear CAL gains were greater in deep (3.7+/-1.7 mm) than in shallow defects (2.2+/-1.3 mm), but no differences were observed in terms of % CAL gains (76.7+/-27.7% and 75.8+/-45%, respectively). The frequency distribution of CAL changes expressed as %s of the baseline INFRA indicates that most of the sites treated with GTR (73% in shallow and 92% in deep defects) gained 50% or more CAL. Furthermore, many defects (64% of shallow and 33% of deep defects) reached 100% of CAL gain. The present study demonstrated that: (i) GTR with bioresorbable barrier membranes resulted in a significant added benefit in comparison with access flap alone; (ii) the linear amounts of CAL gains were greater in deep than in shallow defects; (iii) CAL gains expressed as %s of the baseline depths of the intrabony component, were similar in shallow and deep defects; (iii) the regenerative procedure tested in the present study resulted in CAL gains equal to the depth of the intrabony component of the defect in some, but not in most of the instances.

Guided tissue regeneration with bioabsorbable and expanded polytetrafluoroethylene barrier membranes in the treatment of naturally occurring periodontal defects in dogs

The purpose of the present study was to evaluate the healing events and compare the effects of guided tissue regeneration (GTR) using 3 different membranes: a weakly cross-linked bioabsorbable bovine collagen membrane; a strongly cross-linked bioabsorbable bovine collagen membrane; and a non-resorbable ePTFE membrane. Twenty adult female beagle dogs with naturally occurring periodontitis were subjected to periodontal probing and scaling. In both right and left mandibular quadrants, mucoperiosteal flaps were raised, and after debridement, the roots of experimental premolar teeth received apical reference notches. The following treatments were randomly assigned: 1) gingival flap curettage (GFC) + ePTFE membrane, control membrane; 2) GFC + slightly cross-linked collagen membrane, 1st test membrane; and 3) GFC + strongly cross-linked collagen membrane, 2nd test membrane. The flaps were sutured in such a manner that the membranes were completely covered. All dogs received a soft diet for a 2-week period and an oral hygiene program until time of sacrifice. The animals were randomly scheduled for sacrifice at 2, 4, 12, and 24 weeks. The ePTFE membranes still in place were removed at 6 weeks. The jaws were dissected and specimens prepared for descriptive histology and histomorphometry. The early resorption of the 1st test membrane was achieved at 4 weeks, and the 2nd test membrane at 12 weeks, both with normal inflammatory reaction. Measurements of epithelium, connective tissue attachment, new bone, and neocementum were compared within an animal (paired t test). Analyses were performed on data at 4, 12, and 24 weeks post-healing; little differences were found between these periods. Limited connective tissue repair was favored by the placement of all the membranes (about 20%), with no statistically significant difference. These findings indicate that bioabsorbable collagen membranes with different cross-linking and ePTFE barriers promote similar new attachment in GTR procedures on naturally occurring periodontal defects in dogs.

Guided tissue regeneration update

The ultimate goal of periodontal therapy is to restore periodontal tissues lost through disease or trauma. The most predictable way to accomplish this goal is by guided tissue regeneration (GTR). The principle of GTR is to give preference to certain cells to repopulate the wound area to form a new attachment apparatus. Clinically this is accomplished by placing a barrier over the defect thereby excluding gingival tissues from the wound during early healing. The first generation of GTR barriers were non-resorbable which implies that they have to be removed in a second surgical procedure. Resorbable barriers have recently been introduced, changing GTR into a single-step procedure. Periodontal defects that will predictably benefit from GTR therapy are intrabony, furcation class II and gingival recession defects. This paper reviews the scientific evidence of what can be achieved by GTR procedures for various periodontal defects as well as factors of importance to increase the predictability of a successful treatment outcome.

Clinical and microbiological evaluation of a bioabsorbable and a nonresorbable barrier membrane in the treatment of periodontal intraosseous lesions

Clinical and microbiological features of periodontal healing in barrier membrane-treated sites were determined in a randomized clinical trial. The study included 10 patients with advanced adult periodontitis and a minimum of one set of similar 2 to 3 wall intraosseous periodontal lesions with no furcation involvement. In each patient, one periodontal lesion was treated with a biodegradable membrane and a contralateral lesion with a nonresorbable barrier membrane. Within the preceding 3 months of regenerative therapy, all patients received full mouth osseous surgery except for the sites for regeneration, were instructed in oral hygiene, and were prescribed systemic ciprofloxacin and metronidazole (250 mg of each, TID, 8 days), starting 7 days before membrane placement. At baseline and at 6 months postsurgery, probing depth and clinical attachment level were assessed in each study site. The subgingival presence of suspected periodontal pathogens was determined by non-selective and selective culture and by DNA probe analyses, and of human cytomegalovirus (HCMV) and Epstein-Barr virus type 1 (EBV-1) by a nested-polymerase chain reaction detection method. At baseline, the barrier-treated sites did not differ significantly in clinical and microbial parameters. Mean baseline probing depth was 7.8+/-1.1 mm for bioabsorbable and 7.9+/-1.3 mm for nonresorbable barrier-treated sites. At 6 months, sites treated with bioabsorbable barrier revealed 4.6+/-1.7 mm gain of clinical attachment (range: 1 to 7 mm) and sites treated with nonresorbable barrier 4.2+/-2.0 mm (range: 1 to 8 mm). The 11 barrier-treated sites that harbored 10% or less bacterial pathogens and were free of HCMV and EBV-1 averaged significantly more clinical attachment gain than the 9 sites that yielded more than 10% bacterial pathogens and/or test viruses (5.6 mm versus 3.0 mm; P=0.005). The present data suggest bioabsorbable and nonresorbable barriers provide similar clinical healing of 2 to 3 wall intraosseous periodontal lesions, emphasize the importance of controlling bacterial pathogens prior to and during periodontal healing, and point to the possible detrimental role of HCMV and EBV-1 in periodontal repair.

Treatment of intrabony defects by different surgical procedures. A literature review

This article reviews studies presented during the last 20 years on the surgical treatment of intrabony defects. Treatments include open flap debridement alone (OFD); OFD plus demineralized freeze-dried bone allograft (DFDBA), freeze-dried bone allografts (FDBA), or autogenous bone; and guided tissue regeneration (GTR). The review includes only studies that presented baseline and final data on probing depths, intrabony defect depths as measured during surgery, clinical attachment level (CAL) gain, and/or bone fill. Some reports were case studies and some controlled studies comparing different treatments. In order to assess what can be accomplished in terms of pocket reduction, clinical attachment level gain, and bone fill with the various treatment modalities, data from studies of each treatment category were pooled for meta-analysis in which the data from and power of each study were weighted according to the number of defects treated. In addition, where there were data for each individual defect treated, these were used for simple regression analysis evaluating the influence of intrabony defect depth on treatment outcome in terms of CAL gain and bone fill. This was done in an effort to assess some predictability of the outcome of the various treatments. OFD alone resulted in limited pocket reduction, CAL gain averaged 1.5 mm and bone fill 1.1 mm. Bone fill, but not CAL gain, correlated significantly to the depth of the defect (R=0.3; P < 0.001), but the regression coefficient was only 0.25. OFD plus bone graft resulted in limited pocket reduction. CAL gain and bone fill averaged 2.1 mm. Bone fill showed a somewhat stronger correlation to defect depth than following OFD alone (R=0.43; P < 0.001) with a regression coefficient of 0.37. GTR resulted in significant pocket reduction, CAL gain of 4.2 mm, and bone fill averaging 3.2 mm. CAL gain and bone fill correlated significantly (P < 0.001) to defect depth (R=0.52 and 0.53 respectively) with the largest regression coefficients (0.54 and 0.58 respectively) among the three treatment modalities. By comparing outcomes following the various treatments it became obvious that to benefit from GTR procedures, the intrabony defect has to be at least 4 mm deep.

Histologic evaluation of guided tissue regeneration using 4 barrier membranes: a comparative furcation study in dogs

This study evaluated and compared four different barrier membrane materials used to treat class II mandibular premolar and molar furcations in seven dogs with naturally occurring periodontitis. Five class II furcation defects in each animal were randomly assigned to one of four experimental groups or to a control group. Each defect was treated by surgical debridement, root planing, and barrier membrane coverage with one of the four test materials or no barrier membrane (control). Thus, each animal served as its own control. Following 6 months of healing, block sections were used to histologically measure the amount of regenerated tissue and stereometrically enumerate the inflammatory cell infiltration observed with each of the treatment modalities. The four barrier membrane materials (polycarbonate filter, silicone rubber, expanded polytetrafluoroethylene, and polycaprolactone) all provided a wound healing environment that promoted new cementum formation, with mean values ranging from 1.96 +/- 0.031 mm to 2.18 +/- 0.015 mm, and facilitated alveolar bone regeneration, with mean values ranging from 1.18 +/- 0.019 mm to 1.44 +/- 0.014 mm. Control-treated sites showed mean values of only 0.24 +/- 0.007 mm new cementum formation and 0.32 +/- 0.017 mm bone fill. Polycarbonate filter and polycaprolactone membrane barriers elicited a significantly greater chronic inflammatory cell response of lymphocyte and plasma cell infiltrates as compared to expanded polytetrafluoroethylene and silicone rubber, which were comparable to control-treated sites.

Combined collagen membrane and hydroxyapatite/collagen chondroitin-sulfate spacer placement in the treatment of 2-wall intrabony defects in chronic adult and rapidly progressive periodontitis patients

This study, confined to non-smokers, evaluated guided-tissue regeneration in deep 2-wall intrabony defects using a diphenylphosphorylazide-cross-linked bovine type I collagen membrane supported by a hydroxyapatite/collagen/chondroitin-sulfate spacer in 43 adult periodontitis (AP) and 14 rapidly progressive periodontitis (RPP) patients, no more than 1 defect being randomly selected for each patient. Before surgery and 6 months after surgery, plaque (PI) and sulcus bleeding (SBI) indices, probing pocket depths (PPD), gingival margin locations (GML) and probing attachment levels (PAL) were recorded. During the post-surgical period, the biomaterials were well tolerated in all patients and PI and SBI were kept at a low level. Following therapy, there was a significant gain in PAL (4.2 mm for AP; 3 mm for RPP) and reduction in PPD (6.1 mm for AP; 4.7 mm for RPP) for both groups of patients (p < 0.05). A significantly greater gain in PAL and reduction in PPD were observed for AP compared to RPP patients (p < 0.05). The change in GML was not statistically different between groups (1.8 mm for AP; 1.6 mm for RPP). It is concluded that the combined use of a diphenylphosphorylazide-cross-linked bovine type-I collagen membrane, supported by a hydroxyapatite/collagen/chondroitin-sulfate spacer, is beneficial in improving PAL and reducing PPD in 2-wall intrabony defects in both AP and RPP patients during the quiescent phase of the disease, with statistically better results for the former group. However, longer observation periods are necessary to evaluate the stability of the improvements obtained by this combined treatment approach between and for each group of patients.

Guided tissue regeneration using a collagen membrane in chronic adult and rapidly progressive periodontitis patients in the treatment of 3-wall intrabony defects

This study, confined to non-smokers, evaluated guided tissue regeneration using a diphenylphosphorylazide-cross-linked bovine type I collagen membrane in deep 3-wall intrabony defects in 52 adult periodontitis (AP) and 16-rapidly progressive periodontitis (RPP) patients, previously treated for the acute phase of the disease, no more than one defect being randomly selected for each patient. Before surgery and 6 months after surgery, plaque (PI) and sulcus bleeding (SBI) indices, as well as probing pocket depths (PPD), gingival margin locations (GML) and probing attachment levels (PAL) were recorded. During the post-surgical period, the membranes were very well tolerated in all patients and PI and SBI were kept at a low level. 6 months post-surgical, there was a significant gain in PAL (3.6 mm for AP; 2.6 mm for RPP) and reduction in PPD (5.5 mm for AP; 4.1 mm for RPP) for both groups of patients (p < 0.05). However, neither the change in GML (1.9 mm for AP; 1.5 mm for RPP), nor PPD or PAL yielded a statistically significant difference between AP and RPP patients. The results of this study demonstrated that the treatment of deep 3-wall intrabony defects with a diphenylphosphorylazide-cross-linked collagen membrane in both AP and RPP patients during the quiescent phase of the disease is a treatment modality where the conquences are predictable. However, longer observation periods are necessary to evaluate the stability of the improvements obtained for the 2 groups of patients and the differences between them.

Guided tissue regeneration therapy of 203 consecutively treated intrabony defects using a bioabsorbable matrix barrier. Clinical and radiographic findings

THE AIM OF THIS RETROSPECTIVE three-center study was to evaluate guided tissue regeneration (GTR) therapy in a clinical periodontal setting. The material consisted of 203 consecutively treated intrabony defects > or = 4 mm in 143 patients using a bioabsorbable matrix barrier. Each center followed the same protocol for presurgical, intrasurgical, and follow up examinations. Initial therapy, surgical, and follow-up treatments followed the routine of each center. Treatment was evaluated after 1 year by clinical assessments for probing depth (PD) reduction and clinical attachment level (CAL) gain and by bone fill from computer digitized radiographs. Initial intrabony defect depth averaged 6.3 +/- 1.0 mm clinically and 5.7 +/- 1.8 mm radiographically. Mean PD was reduced from 9.0 +/- 1.0 mm to 3.3 +/- 1.0 mm. Mean CAL gain amounted to 4.8 +/- 1.5 mm corresponding to 79 +/- 13% of the initial intrabony defect depth; 78% of the defects exhibited CAL gain > or = 4 mm. Bone fill averaged 3.2 +2- 1.8 mm. Together with a crestal resorption of 1.1 +/- 1.4 mm this resulted in a defect resolution of 4.3 +/- 1.9 mm or 72%. Forty-seven percent (47%) of the variability in CAL gain could be explained by defect depth, defect width, early barrier exposure, and presence of plaque in the treated area. CAL gain and bone fill were positively correlated to the intrabony defect depth; i.e., the deeper the defect the more the CAL gain and bone fill. Sites with barrier exposure during the first 2 weeks of healing showed significantly less CAL gain than sites at which exposure occurred at a later stage or not at all. Presence of plaque in the treated area had a significant negative impact on both CAL gain and bone fill. It was concluded that GTR-treatment of intrabony defects > or = 4 mm in a periodontal specialist practice will result in clinical attachment level gain and bone fill comparable to what has been demonstrated in case studies and controlled clinical trials. The predictability to obtain CAL gain > or = 4 mm in defects > or = 4 mm was 78%.

Specific issues in clinical trials on the use of barrier membranes in periodontal regeneration

There are presently a number of different barriers available for use clinically in guided tissue regeneration (GTR) procedures. A number of trials using these techniques and comparing different types of barrier membranes are being published in the scientific literature. This review discusses issues related to clinical trials on the use of barrier membranes in periodontal regeneration. Outcome measures, both clinical and histological, are discussed in relation to results following GTR procedures. The difference between regeneration and repair is reviewed as well as methods of clinical and histologic assessment of both these outcomes. Data regarding the impact of patient variables and tooth or defect variables on outcomes are presented and suggestions for study designs are made based on these variables. Aspects of assessing for an appropriate sample size in superiority and equivalency trials using GTR techniques are presented as well as interpretation of results following these trials and their clinical significance.

Regeneration of rat calvarial defects using a bioabsorbable membrane technique: influence of collagen cross-linking

The aim of the present study was to examine the influence of cross-linking on collagen membranes used for guided bone regeneration of calvarial defects in rats. In 48 Wistar rats, divided equally into 4 groups, 1 control and 3 experimental, standardized transosseous circular calvarial defects were made midparietally. In the control group, the defect was only covered by the soft tissue flap while in the 3 experimental groups, 3 differently cross-linked collagen membranes were interposed between the osseous defect and the overlying flap before suturing. The healing was assessed at 10, 20, and 30 days after surgery. The results showed that augmenting the degree of collagen cross-linking diminished the membrane resorption rate. Compared to the sham-operated sites, the membrane protected defects showed significantly more bone regeneration (on average 4 times more) as attested by histology and measured by histomorphometric analysis. Although the bone gain seemed to augment with increasing degrees of cross-linking, the results within the 3 experimental groups were not statistically different. Since longer healing periods might have been necessary to substantiate results within experimental groups, a study is currently undertaken to evaluate this aspect. This study demonstrated the efficacy of collagen membranes in guiding bone regeneration, as well as the importance of the type and degree of cross-linking.

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.

Evaluation of bioabsorbable elastin-fibrin matrix as a barrier in surgical periodontal treatment

The purpose of this investigation was to test clinically the efficiency of a recently described bioabsorbable matrix as a guided tissue regeneration membrane. This matrix was prepared from an original reaction between elastin and fibrin monomers and is now extensively used in several domains of surgery. The study group was composed of 26 patients, with a total of 35 lesions (22 intrabony defects, 8 Class II furcations and 5 Class III furcations) presenting moderate to advanced adult periodontitis. After initial therapy, measurements were made with a calibrated periodontal probe. Probing depth (PD) and gingival margin location (GM) measurements were taken twice: immediately before surgery and after 6 months before re-entry. Clinical attachment level (CAL), vertical osseous level (VOL) and alveolar crest location (AC) measurements were taken during surgery and after 6 months with re-entry procedures for all the patients. Color change of the gingival margin was only observed in 4 defects and device exposure occurred in the proportion of 2 out of the 35 defects. No foreign body reaction was observed in any case. At the intrabony defects mean PD reduction was 5 mm (P < 0.001), and mean gain of CAL was 4 mm (P < 0.001). Mean VOL was 4.3 mm (P < 0.001), mean gingival recession was 0.9 mm (P < 0.05) and mean AC was 0.2 mm (NS). At the Class II furcation defects the mean PD reduction was 4.5 mm (P < 0.001), mean gain CAL vertical was 3.2 mm and CAL horizontal was 4.5 mm (P < 0.001). Gingival recession averaged 1 mm (NS). A complete closure was observed in 2 out of the 8 defects. At the Class III furcation defects the mean PD reduction was 3.6 mm (P < 0.05) and mean CAL-V gain was 1.5 mm (P < 0.02). However the 5 sites showed no horizontal attachment gain and none were unchanged. A very low gingival recession, gingival reaction, crestal bone loss, and device exposure occurred during this study. This preliminary study suggests that the use of a biosynthetic barrier may have beneficial effects in the treatment of intrabony defects and Class II furcation defects. Randomized controlled trials are necessary to evaluate the efficacy and safety of this bioabsorbable membrane in periodontal therapy.

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.