Generalizability of the added benefits of guided tissue regeneration in the treatment of deep intrabony defects. Evaluation in a multi-center randomized controlled clinical trial. Enamel matrix proteins and guided tissue regeneration with titanium-reinforced expanded polytetrafluoroethylene membranes in the treatment of infrabony defects: a comparative controlled clinical trial. Guided tissue regeneration procedure with bioresorbable membranes versus conventional flap surgery in the treatment of infrabony periodontal defects. Treatment of interproximal angular defects by guided tissue regeneration: 1 year follow-up. Treatment of intrabony defects with enamel matrix proteins and guided tissue regeneration. A prospective controlled clinical study. Comparison of treatments of infrabony defects with enamel matrix derivative, guided tissue regeneration with a nonresorbable membrane and Widman modified flap. A pilot study. The use of barrier membranes and enamel matrix proteins in the treatment of angular bone defects. A prospective controlled clinical study. Treatment of deep and shallow intrabony defects. A multicenter randomized controlled clinical trial. Treatment of intrabony defects with enamel matrix proteins or barrier membranes: results from a multicenter practice-based clinical trial. Periodontal repair in intrabony defects treated with a calcium sulfate implant and calcium sulfate barrier. The simplified papilla preservation flap in the regenerative treatment of deep intrabony defects: clinical outcomes and postoperative morbidity. Treatment of gingival recessions by combined periodontal regenerative technique, guided tissue regeneration, and subpedicle connective tissue graft. A comparative clinical study. Treatment of intrabony defects using guided tissue regeneration or enamel matrix derivative: a 3-year prospective randomized clinical study. Clinical evaluation of a biodegradable collagen membrane in guided tissue regeneration. Mucogingival versus guided tissue regeneration procedures in the treatment of deep recession type defects. Enamel matrix proteins in the regenerative therapy of deep intrabony defects. Coronally positioned flap procedures with or without a biodegradable membrane in the treatment of human gingival recession. A 6-year follow-up study.
Several studies have shown that GTR therapy of intrabony defects results in significantly better outcomes than access flap alone. Most of the available data, however, have been produced in highly controlled research environments by a small group of investigators. Generalizability of results to different clinicians and different subject populations has not been evaluated so far.
                This parallel group study involved 143 patients recruited in a practice-based research network of 11 offices in 7 countries. It was designed to evaluate: 1) the applicability of the documented added benefits of GTR in the treatment of intrabony defects to different populations, and 2) the generalizability of the expected results to different clinicians. GTR was compared to access flap alone. Defects, one in each patient, were accessed with a previously described papilla preservation flap in both the test and control group. In addition, GTR sites received application of a bioabsorbable poly-D,L-lactide-co-glycolide membrane. A stringent plaque control regimen was enforced in all patients during the 1-year observation period. Outcomes included gains in clinical attachment (CAL) and reductions in probing depth.
                Observed gains in CAL were 2.18 +/- 1.46 mm for access flap and 3.04 +/- 1.64 mm for the GTR-treated group. The treatment-associated difference was statistically significant (P = 0.03) after correcting for both center effect and defect anatomy. Among the various centers, a 1.73 mm difference in CAL gain was observed. This is a clinically relevant amount, which underlines the significance of center variability in the outcome of periodontal surgical procedures. A frequency distribution analysis of the obtained CAL gains indicated that GTR treatment of deep intrabony defects decreased, with respect to the access flap control, the probability of obtaining only a modest attachment gain at 1 year. Conversely, CAL gains of 4 mm or more were observed in more than 40% of GTR-treated defects and in less than 20% of the controls (P < 0.0001).
                These data indicate that GTR therapy of deep intrabony defects performed by different clinicians on various patient populations resulted in both greater amounts and improved predictability of CAL gains than access flap alone. Several studies have documented the clinical efficacy of guided tissue regeneration (GTR) with non-resorbable expanded polytetrafluoroethylene (ePTFE) membranes and enamel matrix proteins (EMP) in the treatment of infrabony defects. The objective of this controlled clinical study was to compare the clinical outcomes of 3 surgical modalities in the treatment of deep interproximal infrabony defects.
                Ninety (90) defects in 90 healthy subjects affected by chronic periodontitis were assigned to 1 of 3 treatment groups by blocking to prognostic variables. The test group was treated with the application of EMP and the simplified papilla preservation (SPP) technique; the second group was treated with titanium-reinforced ePFTE membranes and the SPP technique; and the third group was treated with the SPP technique used as access flap control procedure. No differences were observed in terms of baseline oral hygiene and defect characteristics among the 3 groups, indicating that the blocking approach was effective. A stringent infection control program was adopted for 1 year.
                The 1-year results indicated that: 1) all treatment modalities resulted in clinically significant improvements in clinical attachment levels (CAL) and reduction in probing depth (PD); 2) a statistically significant treatment effect was demonstrated comparing the EMP test, the membrane control, and the flap control groups in terms of CAL gains; 3) both the EMP test and the membrane control groups showed significant CAL gains compared to the flap control group; 4) a statistically significantly greater amount of CAL gain was demonstrated in GTR-treated compared to EMP-treated patients; 5) deeper residual probing depths but smaller increases in gingival recession were demonstrated following EMP therapy; and 6) smoking habits reduced the clinical outcomes of both regenerative procedures.
                The use of a regenerative procedure is indicated in the treatment of deep vertical bony defects since both the regenerative techniques (GTR and EMD) in the present study resulted in clinically and statistically significant improvements in clinical parameters compared to the access flap procedure. The use of EMP can be helpful in esthetically-sensitive sites and in reducing patient morbidity. Claims are being made that clinical results of periodontal flap surgery are enhanced when membranes are employed to aid GTR in intrabony pockets. It was the aim of our study to determine whether this assumption was true for a certain bioresorbable membrane (Guidor Matrix Barrier).
                44 intrabony defects were treated in 16 patients. In 21 lesions, conventional flap surgery only was performed, while in 23, similar lesion membranes were placed as an additional treatment task. Results were evaluated over a time span of 12 months.
                In all surgical areas, treatment resulted in significant improvement of parameters such as attachment levels and probing depths, as well as index values for plaque and bleeding on probing. This occurred whether membranes had been used or not, without any significant differences when comparing the collective results of both treatment groups.
                Placement of membranes during periodontal surgery for the enhancement of tissue regeneration in intrabony pockets is often both difficult and time consuming. In the light of our clinical results with resorbable membranes, such extra effort seems hardly warranted. The periodontal regeneration of interproximal bone defects of the posterior teeth produced by guided tissue regeneration (GTR), with expanded Polytetrafluoroethylene barrier membranes and conventional therapy, was clinically evaluated in 20 intrabony periodontal defects in 10 patients. The material included the presence of at least two proximal angular lesions for the same patient, probing pocket depth > or = 6 mm, bone defect depth > or = 3 mm, and 2-wall defects with crestal involvement relative to the tooth circumference ranging from 90 to 270 degrees. Healing was clinically evaluated by surgical re-entry of GTR-treated sites (10 sites) and debridement only sites (10 sites) 1 year after initial surgery following a strict plaque control regimen. A significant correlation was observed between probing depth reduction, attachment gain and defect depth (test sites); there was increased bone fill in GTR-treated lesions of 2.95 +/- 1.3 mm corresponding to a 69.4% improvement compared to control sites, and 1.3 +/- 1.0 mm corresponding to a 32% improvement (P < 0.0039). The results demonstrated that bone regeneration is highly reliable, as compared to conventional therapy, in cases of severe periodontal bone loss from posterior teeth provided that the principles of GTR are applied. Utilisation of enamel matrix proteins (EMD) and application of the guided tissue regeneration principle (GTR) are treatment modalities which both have been shown to result in periodontal regeneration. However, it is yet unknown whether the combination of EMD and GTR may additionally favor the regeneration process.
                The aim of the present controlled study was to evaluate clinically the treatment effect of EMD, GTR, combination of EMD and GTR, and flap surgery (control) on intrabony defects.
                56 patients each of whom displaying one intrabony defect of a depth of at least 6 mm were randomly treated with one of the treatment modalities. Prior to surgery and at one year after, the following parameters were evaluated by a blinded examiner: Plaque index (PlI), gingival index (GI), bleeding on probing (BOP), probing pocket depth (PPD), gingival recession (GR) and clinical attachment level (CAL). No statistical significant differences between the four groups were observed at baseline for any of the investigated parameters.
                At 1 year after therapy, the sites treated with EMD demonstrated a mean PPD reduction of 4.1 +/- 1.7 mm and a mean CAL gain of 3.4 +/- 1.5 mm (p<0.001). The sites treated with GTR showed a mean PPD reduction of 4.2 +/- 1.9 mm and a mean CAL gain of 3.1 +/- 1.5 mm (p<0.001). The sites treated with the combined treatment showed a mean PPD reduction of 4.3 +/- 1.4 mm and a mean CAL gain of 3.4 +/- 1.1 mm (p<0.001). In the control group, the mean PPD reduction was 3.7 +/- 1.4 mm (p<0.001) and the mean CAL gain measured 1.7 +/- 1.5 mm (p<0.01). All 4 treatments led to statistically significant PPD reduction and CAL gain. All three regenerative treatments led to higher CAL gain than the control treatment (p<0.05). No statistical significant differences in PPD reduction and CAL gain were observed between the three regenerative treatments.
                It may be concluded that (a) all 3 regenerative treatment modalities may lead to higher CAL gain than the control one, and (b) the combined treatment does not seem to improve the outcome of the regenerative procedure. The purpose of the present study was to compare the efficacy of 3 different surgical procedures in the treatment of infrabony defects: guided tissue regeneration (GTR) with non-resorbable membranes, Widman modified flap (WMF) and enamel matrix derivative (EMD).
                30 patients with an infrabony component > or = 4 mm were selected. 10 were treated with expanded polytetrafluorethylene (ePTFE (Gore - Tex W. L. Gore and Associates, Flagstaff, AZ, USA)) membranes, 10 with WMF and 10 with enamel matrix derivatives (Emdogain (U Biora AB Malm, Sweden)). The efficacy of each treatment modality was investigated through regression analysis. Probing attachment level (PAL) gain, probing depth (PD) reduction and gingival recession (REC) variation were analyzed.
                Both Emdogain (enamel matrix derivative) and ePTFE treatment show significant better results as compared to the WMF procedure in which there were no significant changes in PAL gain and PD reduction at baseline and 1 year after surgery.
                Results from our analysis suggest that there is no statistically significant difference in PAL gain between GTR and EMD. The clinical outcomes of this pilot study may be of little significance, considering the small number of patients, but it has provided an important base for a controlled clinical trial (with a larger number of patients) which is currently in progress. In the present prospective clinical trial, the effect of various regenerative procedures performed at sites with angular bone defects were evaluated. The main outcome variable was probing attachment alteration.
                40 subjects, aged 32-61 years participated. They met the following inclusion criteria: (i) presence of generalized, advanced periodontal tissue destruction; (ii) presence of 2 similar, contralateral, angular bone defects (experimental sites) located in either the maxilla or the mandible; (iii) the defect site must exhibit a probing pocket depth (PPD) of > or = 6 mm, a probing attachment level (PAL) of > or = 7 mm, and a depth of the intrabony component of > or = 3 mm. All subjects had a good oral hygiene standard, were in good general health and did not use any medication. Prior to the start of the study, all subjects received non-surgical treatment for periodontal disease. Baseline clinical measurements (plaque, gingivitis, PPD, PAL and soft tissue recession) of the selected experimental sites were obtained 6 months after the completion of basic therapy. The 40 subjects were randomly divided into 4 treatment groups including 10 subjects each: 3 membrane groups and one Emdogain group. 1 h before surgery, the patients were given 3 g of Amoxicillin. No other antibiotics were prescribed. The test and control sites were treated during the same surgical session. Full thickness flaps were elevated and the exposed root surfaces were planed. Membrane placement: The root surface was rinsed with saline. A barrier membrane (Guidor or Resolut or Periodontal (e-PTFE) material) was positioned to cover the defect and the adjacent 2-3 mm of bone tissue. The control treatment was identical to the test treatment with the exception of barrier placement. Emdogain placement: The exposed root surfaces at both the test and control sites were, during a 2-min period, conditioned with a 24% EDTA gel. Emdogain was applied to the exposed root surface of the test site. In the control site, the vehicle, the PGA gel, was used as placebo control. The flaps were closed and sutured to obtain a complete coverage of the intrabony defect.
                Re-examinations, which were performed 12 months after surgery, disclosed that regenerative therapy, including either the use of barrier membranes or application of enamel matrix proteins to an instrumented root surface in an angular, intrabony defect, enhanced outcome variables such as probing pocket depth and probing attachment gain. It was furthermore demonstrated that clinical improvements were better at sites with deep, than at sites with shallow, intrabony defects.
                The 4 regenerative modalities tested appeared to be equally effective in terms of PPD reduction and PAL gain, and superior to open flap curettage alone. 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. This prospective multicenter, randomized, controlled clinical trial compared the clinical outcomes of enamel matrix proteins (EMD) versus placement of a bioabsorbable membrane in conjunction with guided tissue regeneration (GTR).
                Seventy-five patients with advanced chronic periodontitis were recruited in seven centers in three countries. All patients had at least one intrabony defect of > or = 3 mm. Heavy smokers (> or = 20 cigarettes/day) were excluded. The surgical procedures included access for root instrumentation using the simplified papilla preservation flap and either the application of EMD or the placement of a GTR membrane. At baseline and 1 year following the interventions, clinical attachment levels (CAL), probing depths (PD), recession (REC), full-mouth plaque scores, and full-mouth bleeding scores were assessed. A total of 67 patients completed the study.
                At 1 year, the EMD defects gained 3.1 +/- 1.8 mm of CAL, versus 2.5 +/- 1.9 mm for GTR defects. Probing depth reduction was 3.8 +/- 1.5 mm and 3.3 +/- 1.5 mm, respectively. A multivariate analysis indicated that the differences between EMD and GTR treatments were not significant while a center effect and baseline PD significantly influenced CAL gains. No significant differences in terms of frequency distribution of the outcomes were observed. All cases treated with GTR presented at least one surgical complication, mostly membrane exposure, while only 6% of EMD treated sites displayed complications (P < 0.0001).
                The results of this trial failed to demonstrate superiority of one treatment modality over the other. GTR outcomes in this trial were lower than anticipated based on previous evidence. This was attributed to the high prevalence of post-surgical complications in the GTR group. THIS RANDOMIZED, CONTROLLED, CLINICAL STUDY was designed to evaluate outcome following surgical implantation of an allogeneic, freeze-dried, demineralized bone matrix-calcium sulfate (DBM+CS) composite with a CS barrier in intrabony periodontal defects. Twenty-six patients contributing 26 deep intrabony defects completed the study. Thirteen patients received the DBM+CS implant. Thirteen patients received gingival flap surgery alone (GFS; control). Clinical outcome was assessed at 6 and 12 months postsurgery. At 12 months postsurgery, probing depth (PD) reduction (mean +/-SD) for the DBM+CS and GFS group was to 4.3+/-0.5 and 3.0+/-1.3 mm; clinical attachment gain was to 2.9+/-0.8 and 1.7+/-1.5 mm; and probing bone level gain was to 2.9+/-1.4 and 1.2+/-1.2 mm, respectively. There were no apparent differences between evaluations at 6 and 12 months postsurgery. Clinical improvements were significantly different from presurgery for both groups at both observation intervals (P < 0.01). There were no significant differences between groups in PD reduction and clinical attachment gain. Probing bone level gain was significantly greater in the DBM+CS group compared to controls (P < 0.05). In summary, surgical implantation of DBM+CS with a CS barrier resulted in reduced PD and improved attachment levels comparable to that achieved by gingival flap surgery alone. However, gain in probing bone levels in deep intrabony periodontal pockets assessed by clinical parameters was greater than that observed by gingival flap surgery alone. These changes were noted at both 6 and 12 months after surgery. This regenerative technique needs further biologic evaluation before being generally accepted. 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.
                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.
                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.
                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. Many surgical techniques have been shown to be effective in correcting gingival recessions by covering the exposed root with soft tissue; however, the thickness of the gingival tissue over the root surface probably plays an important role in preventing the recurrence of tissue recession. The aim of the present study was to compare the results of a mucogingival bilaminar technique (BT), guided tissue regeneration (GTR), and a combined periodontal regenerative technique (CPRT) in achieving root coverage and increasing the gingival thickness 1 year after surgical treatment.
                In 45 systemically healthy, non-smoking patients aged 33.6 +/- 4.3 years with no periodontal pockets >4 mm, a Miller's Class I or II gingival recession was treated for root coverage: 15 patients underwent BT (connective tissue with partial-thickness double pedicle graft), 15 GTR by a bioabsorbable membrane, and 15 CPRT by a collagen membrane and collagen-incorporated hydroxyapatite. Before and 1 year after surgical treatments, the following clinical parameters were recorded: gingival recession (GR), probing depth (PD), clinical attachment level (CAL), keratinized tissue width (KT), and gingival thickness (GT); the percentage of root coverage was also calculated and the data were statistically analyzed.
                All 3 techniques yielded significant improvements in terms of GR decrease, CAL and KT gain, and GT increase compared to baseline values. Mean root coverage was 90.0%, 81.01%, and 87.12% in BT, GTR, and CPRT groups, respectively. Complete root coverage was observed in 60%, 40%, and 53.3% of subjects from the BT, GTR, and CPRT groups, respectively. No significant differences were observed among the 3 techniques in GR or CAL improvements; however, BT produced a significantly (P<0.01) greater increase of KT, and BT and CPRT groups showed a significantly (P<0.01) greater increase of GT compared to the GTR group.
                BT, GTR, and CPRT successfully treated gingival recession defects, obtaining comparable percentages of root coverage, but BT and CPRT created a thick gingival tissue significantly greater than that achieved with GTR. The aim of this randomized, controlled, prospective clinical study was to compare guided tissue regeneration (GTR) to enamel matrix derivative (EMD) for the treatment of intrabony defects in patients with chronic advanced periodontitis.
                Forty (39 evaluable) 3-wall intrabony defects, each with a depth > or = 4 mm measured from the crest of the bony defect, were treated in 40 subjects with advanced chronic periodontitis. Regeneration of angular bone defects was induced using non-resorbable membranes (GTR group; n = 20) or EMD (EMD group; evaluable n = 19). Clinical parameters, including probing depth (PD), clinical attachment level (CAL), gingival recession, radiographic measurement of the defect depth, plaque index, and bleeding on probing, were measured at baseline and at 12 and 36 months following surgery.
                Twelve months after surgery, sites treated with GTR demonstrated a mean CAL gain of 2.5 +/- 1.2 mm and a mean reduction in PD of 3.5 +/- 1.2 mm compared to baseline. The corresponding outcomes at 36 months were 2.0 +/- 1.1 mm (CAL) and 3.2 +/- 1.1 mm (PD). Sites treated with EMD demonstrated a mean CAL gain of 2.9 +/- 1.4 mm and a mean reduction in PD of 3.5 +/- 1.4 mm at 12 months, with a mean CAL gain of 2.4 +/- 1.2 mm and a mean PD reduction of 3.1 +/- 1.4 mm at 36 months. The differences in PD reduction and CAL gain were statistically significant between the groups and for each time point compared to baseline. Attachment loss was seen in both groups between the 12- and 36-month observations. Measured radiographic bone fill was 57.0% +/- 21% at 12 months and 53.7% +/- 14.3% at 36 months in the GTR group compared to 50.5% +/- 19% at 12 months and 58.8% +/- 14.9% at 36 months in the EMD group.
                The treatment of intrabony defects in patients with chronic advanced periodontitis using GTR or EMD led to significantly improved clinical parameters. Tests of statistical significance demonstrated better results with EMD, although the absolute differences between treatment modalities was small. Further studies with a larger number of treated defects are necessary to verify these findings. A bio-resorbable type I collagen membrane was investigated as a barrier for guided tissue regeneration. Ten human subjects with at least one pair of contralateral periodontal lesions with probing pocket depths of greater than or equal to 5 mm and radiographic evidence of greater than or equal to 40% bone loss were included. Each patient underwent contralateral surgical flap procedures. A collagen barrier was adapted to the tooth in the experimental defect and the flap replaced and sutured. The controls consisted of the same procedure without the placement of the barrier. Standardized measurements of change in probing attachment levels and fill of intrabony defects were obtained at the time of surgery and 1 year later at the time of surgical re-entry. The differences in change of probing attachment levels and amount of bone fill between individual test and control sites were compared utilizing the student's t-test for paired samples. The mean probing attachment gain in the test sites was 0.56 +/- 0.57 mm, and there was a mean probing attachment loss of 0.71 +/- 0.91 mm in the control sites (P less than 0.01). The gain of bone in test lesions was 1.16 +/- 0.95 mm, while no gain was observed in the control lesions (P less than 0.01). The results of this study demonstrated that sites treated with a collagen barrier comprised of cross-linked bovine Type I collagen exhibited significantly better healing as compared to control sites over the 1-year period of the study. The objective of the study was to compare the clinical efficacy of 3 surgical approaches in the treatment of deep recession type defects. Fifty-four (54) gingival recessions > or = 5 mm were randomly assigned to 1 of the 3 treatment groups by blocking the prognostic variables. The first group was treated with a guided tissue regeneration (GTR) procedure using a bioabsorbable membrane, the second with non-resorbable membrane, and the third with a mucogingival surgical approach consisting of a connective tissue graft combined with a coronally advanced flap (bilaminar technique). No differences, in terms of baseline oral hygiene and defect characteristics, were observed among the 3 groups showing an effective blocking approach. The 1-year results indicated that 1) all treatment approaches resulted in clinically significant root coverage and attachment gain; 2) a statistically significant treatment effect (P = 0.012, ANOVA) was observed comparing the bioabsorbable (4.9+/-0.3 mm), the non-resorbable (4.5+/-0.8 mm), and the bilaminar (5.3+/-0.7 mm) groups, in terms of root coverage; 3) the difference in terms of root coverage between the bilaminar and the non-resorbable membrane groups was statistically significant while differences between the 2 GTR groups or between the bilaminar and the bioabsorbable membrane groups did not reach statistical value; 4) the 95% confidence intervals for the proportions of complete successes showed a similar pattern; 5) no statistical difference was demonstrated in the amount of attachment gain among the 3 groups (P=0.73, ANOVA). A regression model showed that the amount of root coverage was significantly affected by the initial recession depth, the procedure and smoking habits: a poorer root coverage result is expected in case of shallow recession type defects, when either bioabsorbable (P < 0.05) or non-resorbable (P < 0.001) membranes are used instead of a bilaminar technique and if the patient smokes (P < 0.01). It was concluded that the mucogingival bilaminar technique is at least as effective as GTR procedures in the treatment of gingival recession > or = 4 mm and thus recession depth is not the parameter which influences the selection of the surgical procedure. This prospective multicentre randomized controlled clinical trial was designed to compare the clinical outcomes of papilla preservation flap surgery with or without the application of enamel matrix proteins (EMD).
                172 patients with advanced chronic periodontitis were recruited in 12 centers in 7 countries. All patients had at least one intrabony defect of > or =3mm. Heavy smokers (> or =20 cigarettes/day) were excluded. The surgical procedures included access for root instrumentation using either the simplified or the modified papilla preservation flap in order to obtain optimal tissue adaptation and primary closure. After debridement, roots were conditioned for 2 min with a gel containing 24% EDTA. EMD was applied in the test subjects, and omitted in the controls. Postsurgically, a strict plaque control protocol was followed. At baseline and 1 year following the interventions, clinical attachment levels (CAL), pocket probing depths (PPD), recession (REC), full-mouth plaque scores and full-mouth bleeding scores were assessed. A total of 166 patients were available for the 1-year follow-up.
                At baseline, 86 test and 86 control patients presented with similar subject and defect characteristics. On average, the test defects gained 3.1+/-1.5 mm of CAL, while the control defects yielded a significantly lower CAL gain of 2.5+/-1.5 mm. Pocket reduction was also significantly higher in the test group (3.9+/-1.7 mm) when compared to the controls (3.3+/-1.7 mm). A multivariate analysis indicated that the treatment, the clinical centers, cigarette smoking, baseline PPD, and defect corticalisation significantly influenced CAL gains. A frequency distribution analysis of the studied outcomes indicated that EMD increased the predictability of clinically significant results (CAL gains > or =4 mm) and decreased the probability of obtaining negligible or no gains in CAL (CAL gains <2 mm).
                The results of this trial indicated that regenerative periodontal surgery with EMD offers an additional benefit in terms of CAL gains, PPD reductions and predictability of outcomes with respect to papilla preservation flaps alone. Short-term data have indicated that treatment of gingival recession type defects by coronally positioned flap procedures with or without biodegradable membranes may result in similar treatment outcome. The aim of this study was to compare 12-month and 6-year follow-up results for these two treatment approaches.
                Twenty patients with buccal bilateral Miller Class I or Class II gingival recession defects in cuspids or bicuspids were treated randomly by coronally positioned flap alone (20 sites) or in combination with a biodegradable membrane (20 sites). Clinical measurements at baseline, 6, 12 months and 6 years included apical extent of gingival recession, width of the defect at the cemento-enamel junction (CEJ), width of keratinized tissue, as well as attachment level and probing depth. Eleven patients were available for the 6-year evaluation.
                At 12 months (20 sites), both treatments resulted in significant gain of root coverage (p<0.001), stable probing depth, and increased attachment level (p<0.001). The 6-year evaluation (11 sites) showed a significant gain of root coverage for the non-membrane group only (p<0.05). No significant between-group differences were detected for any other treatment variable regardless of smoking status (p>0.05). Compared with baseline, the 6-year results showed that seven membrane sites gained root coverage, three were unchanged and one lost root coverage. For the 11 non-membrane sites, eight gained root coverage, and three were unchanged. The five membrane and the 10 non-membrane sites exhibiting complete root coverage at 6 months were reduced to two and one, respectively, at the 6-year evaluation.
                The coronally positioned flap procedure offers a simple and reliable treatment alternative as a root coverage procedure in Class I and Class II recession type defects. Placement of a biodegradable membrane underneath the flap does not seem to improve neither the short- nor the long-term results. Long-term outcome stability seems to be critically dependent on a continuous follow-up program with re-instruction in non-traumatic brushing habits.
GTR has a greater effect on probing measures of periodontal treatment than open flap debridement, including improved attachment gain, reduced pocket depth, less increase in gingival recession and more gain in hard tissue probing at re-entry surgery. However there is marked variability between studies and the clinical relevance of these changes is unknown. As a result, it is difficult to draw general conclusions about the clinical benefit of GTR. Whilst there is evidence that GTR can demonstrate a significant improvement over conventional open flap surgery, the factors affecting outcomes are unclear from the literature and these might include study conduct issues such as bias. Therefore, patients and health professionals need to consider the predictability of the technique compared with other methods of treatment before making final decisions on use. Since trial reports were often incomplete, we recommend that future trials should follow the CONSORT statement both in their conduct and reporting. 
There is therefore little value in future research repeating simple, small efficacy studies. The priority should be to identify factors associated with improved outcomes as well as investigating outcomes relevant to patients. Types of research might include large observational studies to generate hypotheses for testing in clinical trials, qualitative studies on patient-centred outcomes and trials exploring innovative analytic methods such as multilevel modelling. Open flap surgery should remain the control comparison in these studies.