Soft tissue phenotype modification predicts gingival margin long-term (10-year) stability: Longitudinal analysis of six randomized clinical trials.

AIM: To assess the prognostic value of soft tissue phenotype modification following root coverage procedures for predicting the long-term (10-year) behaviour of the gingival margin. MATERIALS AND METHODS: Participants from six randomized clinical trials on root coverage procedures at the University of Michigan were re-invited for a longitudinal evaluation. Clinical measurements were obtained by two calibrated examiners. A data-driven approach to model selection with Akaike information criterion (AIC) was carried out via multilevel regression analyses and partial regression plotting for changes in the level of the gingival margin over time and interactions with the early (6-month) results of soft tissue phenotypic modification. RESULTS: One-hundred and fifty-seven treated sites in 83 patients were re-assessed at the long-term recall. AIC-driven model selection and regression analyses demonstrated that 6-month keratinized tissue width (KTW) and gingival thickness (GT) influenced the trajectory of the gingival margin similarly in a concave manner; however, GT was the driving determinant that predicted significantly less relapse in the treatments, with stability of the treated gingival margin obtained beyond values of 1.46 mm. CONCLUSIONS: Among a compliant patient cohort, irrespective of the rendered therapy, the presence of at least 1.5 mm KTW and 1.46 mm GT was correlated with the long-term stability of the gingival margin.

EVIDENCE-BASED CLINICAL PRACTICE GUIDELINE FOR TREATMENT OF STAGE IIII PERIODONTITIS.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Sanz M, Herrera D, Kebschull M, Chapple I, Jepsen S, Berglund T, Sculean A, Tonetti MS; EFP Workshop Participants and Methodological Consultants. Treatment of stage I-III periodontitis-The EFP S3 level clinical practice guideline. J Clin Periodontol. 2020 Jul;47 Suppl 22:4-60. doi: 10.1111/jcpe.13290. PMID: 32,383,274. SOURCE OF FUNDING: Internal funds of the European Federation of Periodontology. TYPE OF STUDY/DESIGN: Clinical guideline and recommendations developed based on 15 systematic reviews and consensus from the experts in the field of periodontology.

Long term assessment of root coverage stability using connective tissue graft with or without an epithelial collar for gingival recession treatment. A 12-year follow-up from a randomized clinical trial.

AIM: To evaluate the long term root coverage outcomes of coronally advanced flap plus a connective tissue graft with (CAF + CTG) or without an epithelial collar (CAF + ECTG), and evaluate the adjacent treated sites included in the flap. METHODS: Seventeen of the original 20 subjects included in the randomized clinical trial were available at 12 years (43 sites). Mean root coverage (mRC), keratinized tissue width (KTW), gingival thickness (GT) on the grafted and adjacent sites were evaluated and compared with baseline and 6 months. RESULT: There was a reduction in the mRC at all sites: 16.52% in the CAF + CTG (p > .05), 19.42% in the CAF + ECTG (p < .05) and 34.12% in the CAF-alone (adjacent treated sites) group (p < .05). No significant differences were observed within the groups for changes in KTW, GT and clinical attachment level (CAL) (p > .05). Keratinized tissue width at baseline and at 6 months was found to be predictors for the stability of the gingival margin in the long term. CONCLUSIONS: CAF + CTG and CAF + ECTG were found equally efficacious in maintaining the levels of the gingival margin with a small amount of relapse over the period of 12 years while CAF-alone sites showed a greater gingival recession (GR) reoccurrence.

What Is the Safety Zone for Palatal Soft Tissue Graft Harvesting Based on the Locations of the Greater Palatine Artery and Foramen? A Systematic Review.

PURPOSE: Palatal soft tissue graft harvesting is a common procedure in periodontal and implant dentistry. However, most of the complications after this procedure are associated with the underestimation of anatomic structures, such as the greater palatine artery (GPA). Therefore, the aim of this study was to provide guidelines for a safety zone for palatal harvesting. MATERIALS AND METHODS: A systematic search was conducted to identify cadaveric and computed tomography (CT) or cone beam CT studies assessing the location of the greater palatine foramen (GPF) and the path of the GPA in relation to the maxillary teeth. The effect of age, gender, and cadaveric and CT or cone beam CT studies on the location of the GPF and on the course of the GPA also was assessed. RESULTS: This systematic review included 26 studies, investigating 5,768 hemipalates. The most common location of the GPF was in the midpalatal aspect of the third molar (57.08%). As it traverses the palate anteriorly, the distance from the GPA to the maxillary teeth gradually decreases, except in the second premolar region, where it has the tendency to increase (13.8 ± 2.1 mm). The least distance from the GPA to the teeth was found in the canine area (9.9 ± 2.9 mm), whereas the greatest distance was in the second molar region (13.9 ± 1 mm). A safety zone for palatal harvesting was proposed based on the anatomic findings. CONCLUSIONS: This study provides guidelines for identifying the position of the GPF and defines a safety zone for harvesting a free gingival graft or connective tissue graft, minimizing the risk of GPA injury.

Adjunctive Use of Chlorhexidine Mouthwash to Nonsurgical Periodontal Therapy May Enhance Periodontal Pocket Depth Reduction.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Chlorhexidine mouthwash as an adjunct to mechanical therapy in chronic periodontitis: a meta-analysis. da Costa L, Amaral C, Barbirato D, Leao A, Fogacci M.JADA 2017;148(5):308-18. SOURCE OF FUNDING: The authors' own institutions. TYPE OF STUDY/DESIGN: A meta-analysis.

Adjunctive Use of Systemic Antibiotics (Amoxicillin 500 MG plus Metronidazole 500 MG 3 times a Day for 3 or 7 Days) to Nonsurgical Periodontal Therapy may Improve Clinical Outcomes in Treating Severe Chronic Periodontitis.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Non-surgical periodontal treatment in conjunction with 3 or 7 days systemic administration of amoxicillin and metronidazole in severe chronic periodontitis patients. A placebo-controlled randomized clinical study. Cosgarea R, Juncar R, Heumann C, et al. J Clin Periodontol 2016;43:767-77. SOURCE OF FUNDING: The authors' own institutions TYPE OF STUDY/DESIGN: A randomized clinical trial.

Impact of implant support on mandibular free-end base removable partial denture: theoretical study.

OBJECTIVES: This study investigated the impact of implant support on the development of shear force and bending moment in mandibular free-end base removable partial dentures (RPDs). MATERIAL AND METHODS: Three theoretical test models of unilateral mandibular free-end base RPDs were constructed to represent the base of tooth replacement, as follows: Model 1: first and second molars (M1 and M2); Model 2: second premolar (P2), M1, and M2; and Model 3: first premolar (P1), P2, M1, and M2. The implant support located either at M1 or M2 sites. The occlusal loading was concentrated at each replacement tooth to calculate the stress resultants developed in the RPD models using the free-body diagrams of shear force and bending moment. RESULTS: There was a trend of reduction in the peak shear force and bending moment when the base was supported by implant. However, the degree of reduction varied with the location of implant support. The moment reduced by 76% in Model 1, 58% in Model 2, and 42% in Model 3, when the implant location shifted from M1 to M2 sites. CONCLUSIONS: The shear forces and bending moments subjected to mandibular free-end base RPDs were found to decrease with the addition of implant support. However, the impact of implant support varied with the location of implant in this theoretical study.

Outcomes of regenerative treatment with rhPDGF-BB and rhFGF-2 for periodontal intra-bony defects: a systematic review and meta-analysis.

BACKGROUND: The aim was to evaluate the effects of recombinant human platelet-derived growth factor-BB (rhPDGF-BB) and recombinant human fibroblast growth factor-2 (rhFGF-2) on treating periodontal intra-bony defects, compared to the control (carrier alone). METHODS: Electronic and hand searches were performed to identify eligible studies. The weighed mean differences of linear defect fill (LDF), probing depth (PD) reduction, clinical attachment level (CAL) gain and gingival recession (GR) were calculated using random effect meta-analysis. RESULTS: The searches yielded 1018 articles, of which seven studies were included. Only one included study was considered at low risk of bias. The outcomes that reached statistical significance in comparison to carriers alone included: LDF (0.95 mm, 95% CI: 0.62-1.28 mm or 20.17%, 95% CI: 11.81-28.54%) and CAL gain (0.34 mm, 95% CI: 0.03-0.65 mm) for PDGF, and LDF (21.22%, 95% CI: 5.82-36.61%) for FGF-2. CONCLUSIONS: Within the limits of this review, rhPDGF-BB demonstrated significantly more LDF and CAL gain; rhFGF-2 resulted in significantly higher percentage of LDF.

A randomized clinical trial evaluating the efficacy of the sandwich bone augmentation technique in increasing buccal bone thickness during implant placement. II. Tomographic, histologic, immunohistochemical, and RNA analyses.

OBJECTIVES: This study aimed to evaluate the biologic and structural phenotypes of the bone regenerated via the sandwich bone augmentation (SBA) technique, on buccal implant dehiscence defects. MATERIAL AND METHODS: Twenty-six patients with one buccal implant dehiscence defect each were randomly assigned to two groups. Both groups received a standardized amount of mineralized cancellous and cortical allogenic bone graft. In the test group, a bovine pericardium membrane was placed over the graft, while no membrane was placed in the control group. After 6 months of healing, a bone core biopsy of the regenerated bone was harvested and processed for histologic, immunohistochemical, mRNA, and micro-computed tomography (µCT) analyses. Of the 26 bone core biopsies, only six cores from the test group and six cores from the control group were suitable for the analysis. RESULTS: Bone volume (BV) in the test group was maintained, but tissue maturation appeared to be delayed. In contrast, tissue maturation appeared to be completed in the control group, but BV was compromised. Micro-CT analysis showed that specimens from the control group were more structured and mineralized compared with those from the test group. Histologic analysis showed more residual graft particles scattered in a loose fibrous connective tissue matrix with sparse bone formation in the test group, while the control group showed obvious vital bone formation surrounding the residual graft particles. Positive periostin (POSTN), sclerostin, and runt-related transcription factor-2 (RUNX2) immunoreactivities were detected in both the control and test groups. However, tartrate-resistant acid phosphatase (TRAP) positive was mostly noted in the control group. There were significant differences in POSTN, RUNX2 and VEGF expressions between the test and control groups. CONCLUSION: These findings indicated that the SBA technique was an effective method in preserving adequate structural volume while promoting new vital bone formation. Use of the collagen barrier membrane has successfully maintained the volumetric dimensions of the ridge but might have slowed down the complete maturation of the outermost layer of the grafted site.

Systemic Chemotherapeutic Agents as Adjunctive Periodontal Therapy: A Narrative Review and Suggested Clinical Recommendations.

Periodontitis is an inflammatory condition of the periodontium that leads to destruction of the supporting structures of the tooth, including loss of attachment and alveolar bone. A clinician's first line of treatment for periodontitis is traditionally mechanical periodontal therapy, including oral hygiene instructions together with scaling and root planing. How- ever, it has been shown that mechanical therapy may not always be effective in halting disease. Adjunctive chemotherapeutics, such as systemic antibiotics or host-modulating agents, may improve the treatment outcome of periodontitis. Using relevant terms such as "adjunctive antibiotics" and "systemic chemotherapeutics" in a manual search of the PubMed database, the authors have prepared a narrative review of the chemotherapeutics currently used in the field. Results of the search and review show that adjunctive antibiotics may be useful in cases of aggressive periodontitis, refractory periodontitis, and in some patients who are immunocompromised, such as heavy smokers or poorly controlled diabetics. Host-modulating agents are generally recommended only as the last resort and are limited to the use of submicrobial dose doxycycline. Microbial testing may be indicated, particularly in aggressive periodontitis cases or refractory cases. Using these results, a decision tree is provided for clinicians to determine when adjunctive chemotherapeutics may be indicated.

Comparison between sandwich bone augmentation and allogenic block graft for vertical ridge augmentation in the posterior mandible.

INTRODUCTION: The purpose of this randomized controlled clinical trial was to evaluate 2 different techniques for vertical ridge augmentation (VRA) of the posterior mandible. MATERIALS AND METHODS: Sixteen subjects with 19 posterior mandibular edentulous sites requiring VRA were recruited for the study. Sites were randomly treated with either block allograft (BA; N = 9) or sandwich bone augmentation (SBA; N = 10). Clinical measurements were recorded at the time of surgery (baseline) and 6-month reentry with a custom-made acrylic surgical template. RESULTS: The mean vertical bone gain (VBG) after mean 6.8 months was 44.5% (mean = 1.78 mm [0-5 mm]) in the BA group and 33.3% (mean = 1.0 mm [-1 to 3 mm]) in the SBA group. Significantly higher rates of incision line openings and wound dehiscences were found in the BA group (n = 7/9, 77.8%) as compared with the SBA group (n = 3/10, 30%) (P = 0.037). After adjusting for graft exposure, BA group demonstrated significantly higher VBG than SBA (difference = 2.26 mm, P < 0.001). In addition, graft exposure resulted in significantly less VBG in both groups (P < 0.001). CONCLUSIONS: A higher tendency of wound exposure during VRA was demonstrated when a BA was used compared with the SBA technique. However, if wound exposure could be prevented, higher vertical ridge gain could be achieved with a BA. SUMMARY: The use of a BA in VRA resulted in a maximum of 2 mm more bone height gain compared with the SBA technique if the primary coverage can be achieved during the healing.

Foreign Body Gingivitis.

Foreign body gingivitis (FBG) is a non-plaque induced chronic inflammatory process involving the marginal and/or attached gingiva. It results from the introduction of foreign particulate material, primarily dental prophylaxis paste and restorative dental materials, into the gingival tissues. Clinical presentation varies from an erythematous to vesiculoerosive-like process that may mimic a localized form of desquamative gingivitis or an erosive lichenoid process. Rarely, it may also present with a granular appearance. We describe the clinical presentation, differential diagnosis and clinical management of a 52-year-old Woman who presented with localized chronic inflammation of the maxillary anterior and left posterior gingiva secondary to the presence of foreign material.

A randomized clinical trial evaluating the efficacy of the sandwich bone augmentation technique in increasing buccal bone thickness during implant placement surgery: I. Clinical and radiographic parameters.

OBJECTIVES: Sandwich bone augmentation (SBA) has been proposed to augment the width of edentulous ridges for implant placement. This study aimed to investigate the effect of a membrane on SBA for the regeneration of buccal implant dehiscence defects. MATERIAL AND METHODS: Twenty-six healthy patients, each with a single defect, were randomly assigned into two groups. Both groups received an inner and outer layer of mineralized human cancellous and cortical particulate allograft. In the test group, a bovine pericardium membrane covered the bone grafts, while no membrane was placed in the control group. Cone beam computed tomography (CBCT) scans were taken before and immediately after implant placement and at 6 months post-surgery. RESULTS: All implants placed were successfully osseointegrated at 6 months. Clinical re-entry measurements showed significant buccal bone gain in the test group compared with the control group (P < 0.05). The test group had 1.12, 2.21 and 2.44 mm more buccal bone thickness at 2, 4 and 6 mm below the bone crest. There were no significant differences in the mid-buccal vertical bone height, defect height and width reductions and bone fill between the two groups (P > 0.05). Cone beam computed tomography analysis demonstrated significant buccal bone gain of 1.22 mm in the test group. Radiographic vertical bone loss at 1-year post-surgery showed no significant differences between the groups. CONCLUSION: Sandwich bone augmentation is a predictable technique for regenerating buccal bone on implant dehiscence defects. Addition of a barrier membrane prevented significant horizontal buccal bone resorption as space was maintained more effectively when compared with sites treated without a membrane.

Clinical, microbiological, and salivary biomarker profiles of dental implant patients with type 2 diabetes.

OBJECTIVE: Regulators of peri-implant bone loss in patients with diabetes appear to involve multiple risk factors that have not been clearly elucidated. This study was conducted to explore putative local etiologic factors on implant bone loss in relation to type 2 diabetes mellitus, including clinical, microbial, salivary biomarker, and psychosocial factors. MATERIALS AND METHODS: Thirty-two subjects (divided into type 2 diabetes mellitus and non-diabetic controls), having at least one functional implant and six teeth, were enrolled in a 1-year longitudinal investigation. Analyses of clinical measurements and standardized intra-oral radiographs, saliva and serum biomarkers (via protein arrays for 20 selected markers), and plaque biofilm (via qPCR for eight periodontal pathogens) were performed at baseline and 1 year. In addition, the subjects were asked to respond to questionnaires to assess behavioral and psychosocial variables. RESULTS: There was a significant increase from baseline to 1 year in the probing depth of implants in the diabetes group (1.95 mm to 2.35 mm, P = 0.015). The average radiographic bone loss during the study period marginally increased at dental implants compared to natural teeth over the study period (0.08 mm vs. 0.05 mm; P = 0.043). The control group harbored higher levels of Treponema denticola at their teeth at baseline (P = 0.046), and the levels of the pathogen increased significantly over time around the implants of the same group (P = 0.003). Salivary osteoprotegerin (OPG) levels were higher in the diabetes group than the control group at baseline only; in addition, the salivary levels of IL-4, IL-10, and OPG associated with host defense were significantly reduced in the diabetes group (P = 0.010, P = 0.019, and P = 0.024), while controls showed an increase in the salivary OPG levels (P = 0.005). For psychosocial factors, there were not many significant changes over the observation period, except for some findings related to coping behaviors at baseline. CONCLUSIONS: The study suggests that the clinical, microbiological, salivary biomarker, and psychosocial profiles of dental implant patients with type 2 diabetes who are under good metabolic control and regular maintenance care are very similar to those of non-diabetic individuals. Future studies are warranted to validate the findings in longer-term and larger clinical trials (ClinicalTrials.gov # NCT00933491).

Sinus augmentation via transcrestal approach: a comparison between the balloon and osteotome technique in a cadaver study.

BACKGROUND: The transcrestal approach with osteotomes is a commonly applied and predictable technique for maxillary sinus floor elevation. However, Schneiderian membrane perforation is a common and often inevitable intraoperative complication. Recently, the use of balloons has been proposed to reduce the risk of sinus membrane perforation and to facilitate the surgical technique. The aim of this study was to determine membrane elevation height and perforation rate using the transcrestal balloon technique (B) and a conventional osteotome approach, as control (C). METHODS: Ten fresh, completely edentulous cadaver heads (seven male and three female) were selected. In a split-mouth design, each sinus was randomly assigned to either the experimental or the control technique. Pre-surgical planning was aided by cone-beam computed tomography. During the procedure, an endoscope was used to monitor the elevation procedure and the occurrence of sinus perforation. The elevation continued until either 15 mm (measured from the alveolar crest) was reached or a perforation occurred. The residual ridge and the elevated membrane height were measured and compared with the paired Student's t-test. Presence of sinus perforation was recorded at three cutoff points: 10, 12, and 15 mm. RESULTS: The mean age of the specimens was 77.7 ± 14.2 years (range 49-92). The mean initial, final, and elevated sinus membrane height for the B group was 5.3 ± 1.9, 13.7 ± 1.9, and 8.3 ± 3.1 mm, whereas the correspondent values for the C group were 5.1 ± 2.1, 13.2 ± 2.8, and 8.1 ± 3.1 mm. The incidence of sinus perforation, using 10, 12, and 15 mm as end points was 0%, 22.2%, and 44.4% in the B group, whereas in the C group the respective values were 10.0%, 20.0%, and 50.0%. No statistically significant differences were found between the two groups for all the above-mentioned variables. In addition, mean residual ridge height was not significantly different between the non-perforation and perforation sites in the B group (5.2 ± 2.2 and 5.5 ± 1.7 mm) and in the C group (5.2 ± 2.5 and 5.0 ± 2.0 mm). Three cadavers had perforations in both sinuses, accounting for 66.6% of total number of perforations. CONCLUSIONS: Based on the findings of this study, the balloon and the conventional osteotome approach are comparable in terms of perforation rate as it relates to the elevation height. Also, the amount of residual alveolar bone was not related to the incidence of perforation and the height of sinus elevation.

Updated clinical considerations for dental implant therapy in irradiated head and neck cancer patients.

An increasing number of reports indicate successful use of dental implants (DI) during oral rehabilitation for head and neck cancer patients undergoing tumor surgery and radiation therapy. Implant-supported dentures are a viable option when patients cannot use conventional dentures due to adverse effects of radiation therapy, including oral dryness or fragile mucosa, in addition to compromised anatomy; however, negative effects of radiation, including osteoradionecrosis, are well documented in the literature, and early loss of implants in irradiated bone has been reported. There is currently no consensus concerning DI safety or clinical guidelines for their use in irradiated head and neck cancer patients. It is important for health care professionals to be aware of the multidimensional risk factors for these patients when planning oral rehabilitation with DIs, and to provide optimal treatment options and maximize the overall treatment outcome. This paper reviews and updates the impact of radiotherapy on DI survival and discusses clinical considerations for DI therapy in irradiated head and neck cancer patients.

Living cellular constructs for keratinized tissue augmentation: A 13-year follow-up from a split-mouth randomized, controlled, clinical trial.

BACKGROUND: A 13-year follow-up was conducted of a short-term investigation of the use of living cellular construct (LCC) versus free gingival graft (FGG) for keratinized tissue width (KTW) augmentation in natural dentition, to evaluate the long-term outcomes and assess the changes occurring since the end of the original 6-month study. METHODS: Twenty-four subjects out of the original 29 enrolled participants were available at the 13-year follow-up. The primary endpoint was the number of sites demonstrating stable clinical outcomes from 6 months to 13 years (defined as KTW gain, stability, or ≤0.5 mm of KTW loss, together with reduction, stability, or increase of probing depth, and recession depth [REC] ≤0.5 mm). Secondary outcomes included the assessment of KTW, attached gingiva width (AGW), REC, clinical attachment level, esthetics, and patient-reported outcomes at the 13-year visit, assessing the changes from baseline to 6 months. RESULTS: Nine sites per group (42.9%) were found to have maintained stable (≤0.5 mm or improved) clinical outcomes from 6 months to 13 years. No significant differences were observed for the clinical parameters between LCC and FGG from 6 months to 13 years. However, the longitudinal mixed model analysis showed that FGG delivered significantly better clinical outcomes over 13 years (p < 0.01). LCC-treated sites exhibited superior esthetic outcomes compared to FGG-treated sites at 6 months and 13 years (p < 0.01). Patient-evaluated esthetics were significantly higher for LCC over FGG (p < 0.01). Patient overall treatment preference was also in favor of LCC (p < 0.01). CONCLUSIONS: A similar stability of the treatment outcomes from 6 months to 13 years was found for LCC- and FGG-treated sites, with both approaches shown to be effective in augmenting KTW and AGW. However, superior clinical outcomes were found for FGG over 13 years, while LCC was associated with better esthetics and patient-reported outcomes than FGG.

Early implant bone loss: preventable or inevitable?

Early implant bone loss (EIBL) is defined as the periimplant crestal bone loss occurring from fixture installation to 1 year after loading. This phenomenon has been suggested to be associated with biologic and biomechanical factors. Minimizing EIBL at every treatment step is preferable because this may improve implant health, aesthetics, and overall success. This review presents the host-related factors, implant design characteristics, and the surgical and restorative protocol modifiers that should be evaluated during therapy. Host-related factors may involve the healing capacity, periodontal status, and occlusal function. Implant design features to be considered include the control of biologic width, microgap, and crestal stress distribution. Finally, surgical and restorative factors to be considered are implant site development, minimally invasive surgical approach, implant positioning, and the restorative design and occlusal scheme. Rationale and strategies to control the modifiable factors are also proposed.

Amnion-Chorion Membrane in Open-Wound Approach for Localized Horizontal Ridge Augmentation: A Case Series Report.

INTRODUCTION: Guided bone augmentation often requires extensive releasing of the mucoperiosteal flap to achieve primary wound closure, an invasive procedure that can compromise the keratinized tissue volume and increase patient morbidity. Amnion-chorion membranes have been used to actively promote healing in chronic open-wound situations in the medical field, suggesting that they could be used in a similar manner in the oral cavity.The ability to use open-wound healing techniques for guided bone regeneration would allow clinicians to avoid invasive procedures that cause additional tissue trauma at the surgical site. CASE SERIES: Amnion-chorion membranes were applied over the bone grafting material augmenting localized horizontal ridge defects, and a gap between the flaps was left intentionally during healing. Minor flap releasing procedures were performed in these cases, which demonstrated uneventful soft tissue healing, good volume of bone regeneration and preserved keratinized tissue. CONCLUSIONS: Preliminary clinical outcomes suggested contained minor horizontal ridge defects may be treated satisfactorily in a controlled, open-wound healing manner that reduces surgical trauma, chair time, and patient morbidity.

Guided tissue regeneration: a decision-making model.

BACKGROUND: Guided tissue regeneration (GTR) has the potential to promote periodontal regeneration, which is one of the goals of periodontal surgery. While many successful reports of periodontal regeneration using barrier membranes exist in the literature, considerable heterogeneity of GTR outcomes is more typical of current reports. The reasons for this variability are numerous, but could be attributed to differences in surgical skills and case selection. There is a need for a current analysis of the factors affecting success and the formation of evidence-based treatment guidelines for GTR. METHODS: Available English literature pertaining to guided tissue regeneration was reviewed. Sources included peer-reviewed journal publications, online resources, and textbooks. Specific consideration was made to factors affecting GTR outcomes, especially in the context of systematic reviews and meta-analyses. RESULTS: Factors, including patient systemic conditions and compliance, defect features, local factors and surgical techniques and materials, that influence GTR outcomes were analyzed and entered into a decision-making model. CONCLUSION: A decision-making model was formulated based upon current evidence regarding factors that influence guided tissue regeneration outcomes. Meticulous case selection based upon known influential variables may help to minimize inconsistency in GTR outcomes.