Background: Whether a minimal width of keratinized mucosa (KM) is required to maintain peri‐implant tissue health has been a topic of interest. This systematic review and meta‐analysis aims to investigate the effect of KM on various peri‐implant health‐related parameters.Methods: An electronic search of five databases (from 1965 to October 2012) and a hand search of peer‐reviewed journals for relevant articles were performed. Human cross‐sectional or longitudinal studies with data on the relationship between the amount of KM around dental implants and various peri‐implant parameters, with a follow‐up period of at least 6 months, were included.Results: Eleven studies, seven cross‐sectional and four longitudinal, were included. Weighted mean difference (WMD) and confidence interval (CI) were calculated with meta‐analyses for each clinical parameter. The results showed statistically significant differences in plaque index (PI) and modified PI (WMD = −0.27, 95% CI = −0.43 to −0.11), modified gingival index (mGI) (WMD = −0.48, 95% CI = −0.70 to −0.27), mucosal recession (MR) (WMD = −0.60 mm, 95% CI = −0.85 to −0.36 mm), and attachment loss (AL) (WMD = −0.35 mm, 95% CI = −0.65 mm to −0.06 mm), all favoring implants with wide KM. However, comparisons of other parameters (bleeding on probing, modified bleeding index, GI, probing depth, and radiographic bone loss) did not reach statistically significant differences. The result of heterogeneity test showed only one parameter (AL, P value for the χ² test = 0.30 and I² test = 18%) had a low degree of heterogeneity among analyzed studies; meta‐analyses of other parameters presented moderate‐to‐high degree of heterogeneity. Limitations of the present review include limited number of selected studies (n = 11), existence of heterogeneity and publication bias, and only English‐written articles searched.Conclusion: Based on current available evidence, a lack of adequate KM around endosseous dental implants is associated with more plaque accumulation, tissue inflammation, MR, and AL.

Background: Multiple variables have been shown to affect early marginal bone loss (MBL). Among them, the location of the microgap with respect to the alveolar bone crest, occlusion, and use of a polished collar have traditionally been investigated as major contributory factors for this early remodeling. Recently, soft tissue thickness has also been investigated as a possible factor influencing this phenomenon. Hence, this study aims to further evaluate the influence of soft tissue thickness on early MBL around dental implants.Methods: Electronic and manual literature searches were performed by two independent reviewers in several databases, including Medline, EMBASE, and Cochrane Oral Health Group Trials Register, for articles up to May 2015 reporting soft tissue thickness at time of implant placement and MBL with ≥12‐month follow‐up. In addition, random effects meta‐analyses of selected studies were applied to analyze the weighted mean difference (WMD) of MBL between groups of thick and thin peri‐implant soft tissue. Metaregression was conducted to investigate any potential influences of confounding factors, i.e., platform switching design, cement‐/screw‐retained restoration, and flapped/flapless surgical techniques.Results: Eight articles were included in the systematic review, and five were included in the quantitative synthesis and meta‐analyzed to examine the influence of tissue thickness on early MBL. Meta‐analysis for the comparison of MBL among selected studies showed a WMD of −0.80 mm (95% confidence interval −1.18 to −0.42 mm) (P <0.0001), favoring the thick tissue group. Metaregression of the selected studies failed to demonstrate an association among MBL and confounding factors.Conclusion: The current study demonstrates that implants placed with an initially thicker peri‐implant soft tissue have less radiographic MBL in the short term.

Glendale Lim, DDS, MS/Guo-Hao Lin, DDS, MS/Alberto Monje, DDS, MS/Hsun-Liang Chan, DDS, MS/Hom-Lay Wang, DDS, MSD, PhD: Purpose: The rate of developing soft tissue complications that accompany guided bone regeneration (GBR) procedures varies widely, from 0% to 45%. The present review was conducted to investigate the rate for resorbable versus nonresorbable membranes and the timing of soft tissue complications. Materials and Methods: Electronic and manual literature searches were conducted by two independent reviewers using several databases, including MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Oral Health Group Trials Register, for articles published through July 2015, with no language restriction. Articles were included if they were clinical trials aimed at demonstrating the incidence of soft tissue complications following GBR procedures. Results: Overall, 21 and 15 articles were included in the qualitative and quantitative synthesis, respectively. The weighted complication rate of the overall soft tissue complications, including membrane exposure, soft tissue dehiscence, and acute infection/abscess, into the calculation was 16.8% (95% CI = 10.6% to 25.4%). When considering the complication rate based on membrane type used, resorbable membrane was associated with a weighted complication rate of 18.3% (95% CI: 10.4% to 30.4%) and nonresorbable membrane with a rate of 17.6% (95% CI: 10.0% to 29.3%). Moreover, soft tissue lesions were reported as early as 1 week and as late as 6 months based on the included studies. Conclusion: Soft tissue complications after GBR are common (16.8%). Membrane type did not appear to significantly affect the complication rate, based on the limited number of data retrieved in this study. Technique sensitivity (ie, soft tissue management) may still be regarded as the main component to avoid soft tissue complications and, hence, to influence the success of bone regenerative therapy.

Background: It is thought that infrabony defect morphology affects the outcome of periodontal regenerative surgery. However, this has not been systematically investigated.Aims: To investigate how well defect morphology is described in papers reporting regenerative therapy of periodontal infrabony defects and to investigate its effect on clinical and radiographic outcomes.Materials and Methods: A search was conducted in 3 electronic databases for publications reporting clinical and radiographic outcomes of periodontal intra‐bony defects after regenerative therapy, divided by defect morphology.Results: The initial search resulted in 4487 papers, reduced to 143 after first and second screening. Fifteen of these publications were suitable for a fixed‐effects meta‐analysis. Initial defect depth was found to influence radiographic bone gain 12 months post‐surgery, while narrower angles and increased number of walls influenced both radiographic bone gain and clinical attachment level (CAL) gain at 12 months. These associations seemed to occur irrespective of biomaterials used. Risk of bias ranged from low to high.Conclusion: Deeper defects with narrower angles and increased number of walls exhibit improved CAL and radiographic bone gain at 12 months post‐regenerative surgery. More data are needed about other aspects of defect morphology such as extension to buccal/lingual surfaces.