Indications and Frequency for the Use of Cone Beam Computed Tomography for Implant Treatment Planning in a Specialty Clinic.

PURPOSE: To analyze the indications and frequency for three-dimensional (3D) imaging for implant treatment planning in a pool of patients referred to a specialty clinic over a 3-year period. MATERIALS AND METHODS: All patients who received dental implants between 2008 and 2010 at the Department of Oral Surgery and Stomatology at the University of Bern were included in the study. The influence of age, gender, and time of treatment (2008 to 2010) on the frequency of use of two-dimensional (2D) radiographic imaging modalities alone or in combination with 3D cone beam computed tomography (CBCT) scans was analyzed. Furthermore, the influence of the indication, location, and need for bone augmentation on the frequency of use of 2D imaging modalities alone or in combination with CBCT was evaluated. RESULTS: In all, 1,568 patients (792 women and 776 men) received 2,279 implants. Overall, 633 patients (40.4%) were analyzed with 2D imaging procedures alone. CBCT was performed in 935 patients (59.6%). There was a statistically significant increase in CBCT between 2008 and 2010. Patients older than 55 years received a CBCT scan in addition to 2D radiographic imaging statistically significantly more often. Additional 3D imaging was most frequently performed in the posterior maxilla, whereas 2D radiographs alone exhibited the highest frequency in the anterior mandible. The combination of 2D with CBCT was used predominantly for implant placement with simultaneous or staged guided bone regeneration or sinus elevation. CONCLUSION: Based on these findings from a specialty clinic, the use of additional CBCT imaging for implant treatment planning is influenced by the indication, location, local anatomy (including the need for bone augmentation), and the age of the patient.

Linear mixed model approach to network meta-analysis for continuous outcomes in periodontal research.

AIM: Analysing continuous outcomes for network meta-analysis by means of linear mixed models is a great challenge, as it requires statistical software packages to specify special patterns of model error variance and covariance structure. This article demonstrates a non-Bayesian approach to network meta-analysis for continuous outcomes in periodontal research with a special focus on the adjustment of data dependency. DATA: Seventeen studies on guided tissue regeneration were used to illustrate how the proposed linear mixed models for network meta-analysis of continuous outcomes. METHODS & RESULTS: Arm-based network meta-analysis use treatment arms from each study as the unit of analysis; when patients are randomly assigned to each arm, data are deemed independent and therefore no adjustment is required for multi-arm trials. Trial-based network meta-analysis use treatment contrasts as the unit of analysis, and therefore treatment contrasts within a multi-arm trial are not independent. This data dependency occurs also in split-mouth studies, and adjustments for data dependency are therefore required. CONCLUSIONS: Arm-based analysis is the preferred approach to network meta-analysis, when all included studies use the parallel group design and some compare more than two treatment arms. When included studies used designs that yield dependent data, the trial-based analysis is the preferred approach.

The use of guided tissue regeneration techniques among endodontists: a web-based survey.

INTRODUCTION: The purpose of this study was to determine factors and clinical situations that influence an endodontist's decision to use guided tissue regeneration (GTR) techniques during endodontic root-end surgery. METHODS: An invitation to participate in a web-based survey was e-mailed to 3,750 members of the American Association of Endodontists. Data were collected from 1,129 participants, representing a 30.1% completion rate. The number of questions varied from 3 to 11 depending on individual responses. RESULTS: 40.7% of respondents who perform root-end surgeries also use GTR techniques. The clinical situation in which GTR techniques are used most often is for transosseous lesions. Barrier membranes and bone replacement grafts are each used by more than 85% of respondents using GTR techniques. Insufficient training and insufficient evidence in support of its use were selected as the predominant reasons for not using GTR techniques at 42.4% and 32%, respectively. CONCLUSIONS: Although over 40% of respondents are currently using GTR techniques in conjunction with their root-end surgeries, a majority of those who do not use GTR indicated they would consider using these techniques with better evidence and available training.

A survey on regenerative surgery performed by Swiss specialists in periodontology with special emphasis on the application of enamel matrix derivatives in infrabony defects.

This survey aimed to evaluate the common practice of regenerative periodontal surgery with special regard to the use of enamel matrix derivatives (EMD, Emdogain® ) by board-certified specialists in periodontology and non-certified, but active members of the Swiss Society of Periodontology (SSP). A cross-sectional postal survey of 533 dentists, representing all members of the SSP practising in Switzerland, was conducted. The questionnaire consisted of three sections, assessing: 1) general personal information regarding the practice setting and education, 2) general questions regarding periodontal surgery practices and 3) specific questions regarding the use of EMD. The information obtained was compared and differences between specialists and non-specialists were calculated. P-values smaller than 5% were considered significant. Sixty-nine percent of the specialists answered the questionnaire, compared to only 37.4% of the non-specialists (overall: 42.4%). In general, specialists performed surgeries more frequently, and presented a significantly higher percentage of EMD users than the non-specialists. The application guidelines were followed in general. Some differences were observed in application and selection criteria. The subjective perception of clinical success varied greatly among clinicians. Residual pockets were reported to be present in approximately one third of the defects after therapy. In conclusion, this survey revealed that EMD was used on a regular basis by dentists performing periodontal therapy. In addition, the answers by both groups generally corresponded well with the current available literature.

Surgical periodontal therapy at Tokyo Dental College Suidobashi Hospital: a statistical profile in 2010-2011.

The aim of the present study was to investigate the profile of surgical periodontal therapy performed at the Suidobashi Hospital of Tokyo Dental College, during the period of April 2010 through March 2011. A total of 112 periodontal surgeries in 69 patients (mean age: 51.4 years; 28 men and 41 women) were registered for the data analysis. The surgical interventions performed by 17 dentists comprised 79 cases of open flap debridement, 27 cases of periodontal regenerative therapy with enamel matrix derivative and 6 cases of periodontal plastic surgery. Eighty percent of the surgical sites were in the molar region and 41 cases had furcation involvement. In these patients, an improvement in oral hygiene status was observed prior to surgery: the mean plaque score of 45% at initial visit was significantly reduced to 31% after initial periodontal therapy (p<0.01). At sites that subsequently received open flap debridement or periodontal regenerative therapy, the mean probing depth and clinical attachment level after initial therapy was 6.4 mm and 7.6 mm, respectively. These values were significantly lower than those at initial visit (p<0.01). Lower prevalence of sites with positive bleeding on probing was observed after initial therapy. The initial periodontal therapy performed was considered to be effective in improving the periodontal condition of the sites prior to surgery. More effort, however, is indicated in improvement of patient oral hygiene status.

Partial least squares path modelling for relations between baseline factors and treatment outcomes in periodontal regeneration.

BACKGROUND: Some clinical outcome variables in periodontal research are mathematically coupled, and it is not feasible to include all the mathematically coupled variables in an ordinary least squares (OLS) regression analysis. The simplest solution to this problem is to drop at least one of the mathematically coupled variables. However, this solution is not satisfactory when the mathematically coupled variables have distinctive clinical implications. MATERIAL AND METHODS: Partial least squares (PLS) methods were used to analyse data from a study on guided tissue regeneration. Relationships between characteristics of baseline lesions and treatment outcomes after 1 year were analysed using PLS, and the results were compared with those from OLS regression. RESULTS: PLS analysis suggested that there were multiple dimensions in the characteristics of baseline lesion: vertical dimension was positively associated with probing pocket depth (PPD) reduction and clinical attachment level (CAL) gain, whilst horizontal dimension was negatively associated with the outcome. Baseline gingival recession had a negative association with PPD reduction but a small positive one with CAL gain. CONCLUSION: PLS analysis provides new insights into the relationships between baseline characteristics of infrabony defects and periodontal treatment outcomes. The hypothesis of multiple dimensions in baseline lesions needs to be validated by further analysis of different datasets.

Estado atual do uso de barreiras para a regeneração periodontal em defeitos de furca: evidências clínicas / Update in the use of barriers for periodontal regeneration in furcation defects: clinical evidences

O emprego da RTG na prática clínica ainda carece de evidências na literatura. Esta revisão sistemática procurou avaliar o uso de barreiras para o tratamento de lesões de furca quando comparado ao acesso cirúrgico. Foi procurado na literatura ensaios clínicos randomizados com pelo menos 6 meses de duração e que comparassem o uso da RTG com acesso cirúrgico. Quatro estudos estavam de acordo com os critérios de inclusão. Dentre estes, o percentual de fechamento de lesões de furca de grau II com a RTG apresentado por três artigos ficou entre 0 e 30%. O emprego da RTG apresenta pouca previsibilidade e vantagens modestas no tratamento de lesões de furca de grau II em molares mandibulares. Ainda não há na literatura evidência suficiente para a avaliação da RTG em lesões de furca de graus I e III.

The use of GTR in clinical practice still lacks evidence in the literature. This systematic review evaluated the use of barriers for the treatment of furcation involvements as compared to open flap debridement (OFD). The search looked for randomized controlled clinical trials with at least 6 months of follow-up, that compared the use of GTR with OFD. Four studies met the inclusion criteria. Among them, the percent of complete closure of degree II furcation defects with GTR, presented in 3 articles varied between 0 and 30%. The use of GTR has low predictability and modest advantages in the treatment of degree II furcation defects in lower molars. The literature still lacks sufficient evident to evaluate GTR in degrees I and III furcation defects.

Is there a temporal trend in the reported treatment efficacy of periodontal regeneration? A meta-analysis of randomized-controlled trials.

BACKGROUND/AIM: The aim of study was to conduct a meta-analysis to investigate whether or not there was a temporal trend in the treatment efficacy reported in the randomized-controlled trials (RCTs) on guided tissue regeneration (GTR) or enamel matrix protein derivatives (EMD) in the treatment of infrabony defects. MATERIAL AND METHODS: The treatment outcomes were changes in probing pocket depth (PPD) and clinical attachment level (CAL). Weighted multilevel and ordinary regression analyses were performed to test the temporal relationship between treatment effect difference or treatment effectiveness and publication years. RESULTS: For PPD reduction, non-significant positive relationships were found in the treatment effect difference or treatment effect of both GTR and flap operation. For CAL gain, a small positive relationship was found in the treatment effect difference, but a significant positive trend in the treatment effect of flap operation was found. No significant temporal trend was found in the treatment effect difference for EMD. CONCLUSIONS: There was no evidence to support or refute a temporal trend in the treatment effect of regenerative procedures, but a positive trend was observed in the control group. These results suggest that only RCTs should be included in the meta-analysis, as the treatment effect of the control group may not be constant.

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.

Long-term results and survival rate of implants treated with guided bone regeneration: a 5-year case series prospective study.

One of the key factors for attaining osseointegration is the presence of an adequate osseous volume. In patients with inadequate osseous width or height, a bone augmentation using the guided bone regeneration (GBR) concept may be applied either with a simultaneous or a staged approach. The aim of this multicenter prospective case series study was to evaluate the efficacy and predictability of the GBR technique (simultaneous approach) in patients with peri-implant osseous defects, both dehiscences and fenestrations. Results 5 years post-treatment (survival rates and marginal bone level) were assessed. A total of 19 consecutive patients with 26 peri-implant osseous defects (20 dehiscences and six fenestrations) were treated during the period from September 1992 to June 1993 with a simultaneous GBR approach using non-resorbable membranes combined with autogenous bone grafts or decalcified freeze-dried bone allograft. The mean osseous augmentation was 94.8%. Marginal bone levels at re-entry and 5 years after surgery were calculated from standardized periapical radiographs. One implant was lost 3 months after loading. Thus, the cumulative survival rate was 96.1% after 5 years. The mean marginal bone level after 5 years was 2.03 mm (SD=+/-0.5), without a difference between mesial and distal sites. This study demonstrates that implants with peri-implant defects that are treated with GBR had similar survival rates and crestal bone levels compared with implants in native bone.

Statistical power for analyses of changes in randomized controlled trials.

Randomized controlled trials (RCTs) are widely recommended as the most useful study design to generate reliable evidence and guidance to daily practices in medicine and dentistry. However, it is not well-known in dental research that different statistical methods of data analysis can yield substantial differences in study power. In this study, computer simulations are used to explore how using different univariate and multivariate statistical methods of analyzing change in continuous outcome variables affects study power, and the sample size required for RCTs. Results show that, in general, analysis of covariance (ANCOVA) yields greater power than other statistical methods in testing the superiority of one treatment over another, or in testing the equivalence between two treatments. Therefore, ANCOVA should be used in preference to change score or percentage change score to reduce type II error rates.

The use of a bioabsorbable barrier for regenerative management of marginal tissue recession. I. Report of 100 consecutively treated teeth.

BACKGROUND: Periodontal plastic surgical procedures aimed at coverage of exposed root surfaces have evolved into routine treatment modalities. The present study was designed to assess the effectiveness and the predictability of a bioabsorbable barrier in the treatment of human recession defects utilizing a single-step surgical procedure. METHODS: One hundred consecutive single and multiple adjacent Miller Class I, II, and III buccal recession defects in 41 patients were treated with a combination of a bioabsorbable barrier and coronally advanced flap technique. Clinical parameters were recorded immediately prior to surgery, at 3 months, and after a minimum of 6 months. RESULTS: A highly significant reduction in recession depth from a mean value of 3.2 +/- 0.9 mm preoperatively to 0.3 +/- 0.5 mm postoperatively, corresponding to a mean root coverage of 92. 7% +/- 14.1%, was obtained. Complete (100%) root coverage was obtained in 75% of the sites. Factors adversely affecting root coverage were membrane exposure postoperatively and preoperative recession depth > or =4 mm. In addition, inferior results were achieved at mandibular incisor and maxillary molar sites. Factors having no effect on root coverage included maxillary versus mandibular sites and single versus multiple adjacent sites. CONCLUSIONS: The use of guided tissue regeneration in periodontal plastic surgery is highly predictable, and highly esthetic root coverage can be gained without requiring a second surgical procedure or a second surgical site and is, therefore, an attractive alternative to conventional grafting techniques.

Guided tissue regeneration procedure with bioresorbable membranes versus conventional flap surgery in the treatment of infrabony periodontal defects.

AIM: 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). METHOD: 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. RESULTS: 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. CONCLUSIONS: 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.

Changes in the provision of implant-supported prostheses at the Academic Centre for Dentistry Amsterdam (ACTA) from 1989 to 1995.

PURPOSE: Over the last decade, oral implantology has become a major treatment modality to aid the restoration of reduced dentitions. The present study monitored and quantified changes within a 5-year interval (1989-1991 [denoted as 1990*] to 1995) in the provision of different types of implant-supported superstructures and characteristics of recipient patients at the Academic Centre for Dentistry Amsterdam (ACTA). MATERIALS AND METHODS: All patients who received oral implants in 1990* and in 1995 were selected, and their files (95 and 105, respectively) were consulted. Data of interest were retrieved retrospectively, compared, and statistically analyzed using Chi-squared tests. RESULTS: A number of statistically significant differences was apparent between these 2 periods. By 1995 there was a threefold increase in both the number of patients and the number of implants placed per year. The patient group of < or = 40 years of age had significantly increased, from 7% to 23%. Also, in 1995 more maxillae were implanted than in 1990* (44% vs 26%). Whereas the majority of implanted patients was edentulous in 1990* (64%), the majority in 1995 was partially edentulous (60%). By 1995, the new technique of guided bone regeneration (GBR) using membranes was evidenced (no GBR in 1990* vs 33% of all patients in 1995 receiving some form of local GBR therapy). With respect to the type of superstructures, there was a strong increase in the number of single-tooth replacements (from 4% to 23%). In the edentulous group, the majority of superstructures in 1990 was fixed prostheses (64%), whereas in 1995 the majority was overdentures (71%). CONCLUSION: Major changes in oral implantology treatments were noticed between the 1990* and 1995 periods at ACTA. There is a trend toward implanting younger patients for partial implant-supported reconstructions using more regenerative procedures and with a more equal distribution in the maxilla and mandible.

The use of barrier membranes and enamel matrix proteins in the treatment of angular bone defects. A prospective controlled clinical study.

UNLABELLED: 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. MATERIAL AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Treatment of ligature-induced peri-implantitis defects by regenerative procedures: a clinical study in dogs.

We carried out a clinical evaluation of the hard tissue fill following treatment of ligature-induced peri-implantitis in dogs. Four dogs were used and their mandibular premolars (P2, P3 and P4) were removed. After 3 months of healing, two titanium implants were placed on each side of the mandible. After 3 months, the abutment connection was performed, and experimental peri-implantitis was induced by placement of cotton ligatures in a submarginal position. The ligatures and abutments were removed after one month, and the peri-implant bone defects were assigned randomly to one of the treatments: debridement (control), debridement plus guided bone regeneration (GBR), debridement plus mineralized bone graft (BG), and debridement plus guided bone regeneration associated with a mineralized bone graft (GBR + BG). Clinical measurements of the peri-implant bone defects before and 5 months after treatment revealed no statistically significant differences between the defects treated by GBR, BG and GBR + BG. These 3 treatment methods provided more hard tissue fill than debridement alone (p < 0.05). Thus, it can be concluded that GBR, BG or a combination of the two techniques can enhance the hard tissue fill in defects caused by peri-implantitis in dogs.

Guided tissue regeneration in the treatment of human infrabony defects. Clinical, radiographical and microbiological results: a pilot study.

The aim of the study was to evaluate the clinical, radiographical and microbiological outcome after using guided tissue regeneration (GTR) with a bioabsorbable membrane, Resolut. Subjects with bilateral infrabony defects at single rooted teeth were selected. A total of 22 teeth, 2 in each 1 of 7 patients and 4 in 2 patients, with probing pocket depth > or =5 mm, 3 months after scaling, participated. At baseline, assessments of plaque and gingival indices, bleeding on probing, probing pocket depth and probing attachment level were recorded and reproducible radiographs for computer-based bone level measurements were taken. Bacterial samples were collected to investigate the presence of periodontitis-associated bacteria, e.g., Porphyromonas/Prevotella- and Fusobactrium-like micro-organisms. One tooth was randomly treated with GTR and the contralateral with an open debridement procedure as a control. Clinical, radiographical and microbiological examinations were repeated 6 and 12 months postoperatively. Both procedures demonstrated a statistically significant improvement of gingival conditions, reduction of pocket depths and gain of attachment. When evaluating the differences between test and control teeth, none of the clinical parameters yielded statistical difference. Computer-based bone-level measurements showed only small differences in the majority of both test and control sites. The differences were not significant. Periodontitis-associated bacteria were present at baseline, but the appearance was not related to any specific site or patient and did not demonstrate any unwanted change in the 6- and 12-month samples. The findings suggest that the clinical, radiographical and microbiological improvements were not significantly enhanced with the GTR therapy.

Expanded polytetrafluoroethylene and dental rubber dam barrier membranes in the treatment of periodontal intrabony defects. A comparative clinical trial.

As observed in previous case reports, dental rubber dam (DRD) can be utilized as a barrier membrane in the guided tissue regeneration (GTR) technique for the treatment of periodontal intrabony defects. The purpose of the present study was (1) to confirm the validity of DRD as a suitable material in regenerative procedures and (2) to compare, in a split-mouth clinical trial, the effectiveness of DRD-made membranes in the treatment of periodontal intrabony defects versus that of expanded polytetrafluoroethylene (e-PTFE) barriers. 22 systemically healthy non-smoker adult periodontitis patients (7 male, 15 female) aged between 35 to 58 years were selected for the study. In each patient, a couple of 2-3 wall intrabony defects, located in different quadrants, were treated by a GTR technique using DRD (test sites) and e-PTFE (control sites), respectively. Performing a strict control of the oral hygiene level and of the marginal gingival health during the whole period of study, clinical (pocket probing depth, PPD; probing attachment level, PAL; gingival recession, GR) and intrasurgical (depth of the defect's intraosseous component, IOC; level of the alveolar crest, ACL) parameters were recorded at baseline and at the 1-year re-entry procedure in each experimental site. Furthermore, the coronal level of the newly formed tissue from the base of the defect (NFTL) and the vertical bone gain (VBG) were calculated at the time of membrane removal and after the re-entry procedure respectively. Membranes were removed from both test and control sites after 5 weeks; however, exposure of the membrane always occurred in test sites whereas it was observed in only 6 out of 22 control sites, this fact leading to an incomplete coverage of the regenerated tissue by the gingival flap in 18 out of 22 test sites. In both test and control sites, a statistically significant improvement of clinical and intrasurgical parameters occurred at the end of the study period; however, a significantly greater improvement was observed in control sites for PAL (+4.0 mm versus +3.0 mm; p<0.05) and VBG (3.9 mm versus 2.9 mm; p<0.05) although at the time of membrane removal, NFTL was similar between the experimental sites (test: 5.8; control: 5.6; p>0.05). Conversely, test sites exhibited a statistically significant greater increase in gingival recession (+1.9 versus +1.2; p<0.05) and alveolar crest resorption (-1.1 versus -0.3, p<0.01) in comparison to controls. It was concluded that (1) DRD is a suitable material to be used as a barrier membrane in GTR procedures although (2) e-PTFE membranes can provide a greater improvement in PAL and VBG, probably because of the difficulty in completely covering the regenerated tissue due to the fact that the gingival tissues have undergone a consistent recession in DRD-treated sites. Further studies are needed to demonstrate if an adequate coverage of the regenerated tissue in DRD-treated sites can eliminate these differences.