Guo Hao Lin

The Significance of Keratinized Mucosa on Implant Health: A Systematic Review

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 χ(2) test = 0.30 and I(2) 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.

Reconstructive Procedures for Treating Peri-implantitis A Systematic Review

This review aimed at evaluating the effectiveness of reconstructive procedures for treating peri-implantitis. Searches of electronic databases and cross-referencing were performed for human comparative clinical trials with ≥10 implants for ≥12 months of follow-up, reporting radiographic defect fill and at least one of the following parameters: probing depth reduction, clinical attachment level gain, bleeding on probing reduction, and mucosal recession. The searches retrieved 430 citations. Only 1 randomized controlled trial was identified, which compared reconstructive therapy and open flap debridement. Case series studies were also included to evaluate the overall performance of the reconstructive procedures. Twelve studies were finally included. Meta-analysis revealed that the weighted mean radiographic defect fill was 2.17 mm (95% confidence interval [CI]: 1.46-2.87 mm), probing depth reduction was 2.97 mm (95% CI: 2.38-3.56 mm), clinical attachment level gain was 1.65 mm (95% CI: 1.17-2.13 mm), and bleeding on probing reduction was 45.8% (95% CI: 38.5%-53.3%). Great variability in reparative outcomes was found, attributed to patient factors, defect morphology, and reconstructive agents used. Currently, there is a lack of evidence for supporting additional benefit of reconstructive procedures to the other treatment modalities for managing peri-implantitis.

Surgical Management of Peri-Implantitis: A Systematic Review and Meta-Analysis of Treatment Outcomes

BACKGROUND This systematic review was requested by the Task Force of the American Academy of Periodontology as a follow-up study of the 2013 report, with an aim to investigate the efficacy of different surgical approaches to treat peri-implantitis. METHODS A search of four electronic databases from January 1990 to May 2013 was performed. Studies included were human clinical trials published in English that applied surgeries for treating peri-implantitis. Parameters evaluated included probing depth (PD) reduction, clinical attachment level gain, bleeding on probing (BOP) reduction, radiographic bone fill (RBF), and mucosal recession. The weighted mean (WM) and the 95% confidence interval of the studied parameters were estimated with the random-effect model. RESULTS A total of 1,306 studies were initially identified, after reviewing titles, abstracts, and full texts, and 21 articles, 12 of which were case series, were finally included. Four treatment groups were identified: 1) access flap and debridement; 2) surgical resection; 3) application of bone grafting materials; and 4) guided bone regeneration. The mean initial PD ranged from 4.8 to 8.8 mm, with initial BOP ranging from 19.7% to 100%. Short-term follow-ups (3 to 63 months) revealed that the available surgical procedures yielded a WM PD reduction of 2.04 (group 2) to 3.16 mm (group 4), or 33.4% to 48.2% of the initial PD. The WM RBF was 2.1 mm for groups 3 and 4. CONCLUSIONS Within the limitation of this systematic review, the application of grafting materials and barrier membranes resulted in greater PD reduction and RBF, but there is a lack of high-quality comparative studies to support this statement. The results might be used to project treatment outcomes after surgical management of peri-implantitis.

Alterations in bone quality after socket preservation with grafting materials: a systematic review.

PURPOSE While the ability of various grafting materials to preserve extraction socket morphology has been adequately reviewed, the quality of the grafted bone in the socket is not as well understood. This systematic review aimed to compare the proportion of vital bone and connective tissue between grafted and naturally healed sockets. MATERIALS AND METHODS An electronic search of five databases (from 1965 to November 2011) and a hand search of peer-reviewed journals for relevant articles were performed. Human clinical trials that compared histologic components of soft and hard tissues in augmented sockets and naturally healed sites, with at least five samples per group, were included. RESULTS Eight studies (five randomized controlled trials and three controlled clinical trials) were included. The mean percentages of vital bone and connective tissue in natural healing sockets were 38.5% ± 13.4% and 58.3% ± 10.6%, respectively. Limited evidence (one to two articles for each material) implied that vital bone fraction was not different with demineralized allografts and autografts and increased by 6.2% to 23.5% with alloplasts in comparison to nongrafted sites. Four studies investigating the effect of xenografts were available, with equivocal results. The difference in the mean percentage of vital bone ranged from -22.2% (decrease) to 9.8% (increase). Connective tissue content decreased with the use of the aforementioned bone substitutes. Considerable residual hydroxyapatite and xenograft particles (15% to 36%) remained at a mean of 5.6 months after socket augmentation procedures. CONCLUSIONS Based on a limited number of prospective comparative studies, the use of grafting materials for socket augmentation might change the proportion of vital bone in comparison to sockets allowed to heal without grafting. Whether these changes in bone quality will influence implant success and peri-implant tissue stability remains unknown.

Effects of Currently Available Surgical and Restorative Interventions on Reducing Midfacial Mucosal Recession of Immediately Placed Single-Tooth Implants: A Systematic Review

BACKGROUND Procedures to improve peri-implant soft-tissue outcomes of single, immediately placed implants are a topic of interest. This systematic review investigates the effect of various surgical and restorative interventions on implant mid-buccal mucosal level. METHODS An electronic search of five databases (January 1990 to December 2012) and a manual search of peer-reviewed journals for relevant articles were performed. Randomized controlled clinical trials (RCTs), prospective cohort studies, and case series with at least nine participants were included, with data on midfacial mucosal recession (MR) of immediately placed implants following various surgical and restorative interventions with a follow-up period of at least 6 months. RESULTS Thirty-six studies, eight RCTs, one cohort study, and 27 case series were eligible. Six interventions were identified and reviewed: 1) palatal/lingual implant position; 2) platform-switched abutments; 3) flapless approach; 4) bone grafts to fill the gap between buccal plate and fixture; 5) connective tissue grafts; and 6) immediate provisionalization. Three studies consistently showed that palatally/lingually positioned implants had significantly less MR when using tissue-level implants. Mixed results were reported for interventions 2, 3, 5, and 6. One study was available for intervention 4 and did not show a benefit. CONCLUSIONS Some interventions might be adopted to reduce the amount of MR on implants with the immediate placement approach, as suggested by the included studies, with various levels of evidence. The conflicting results among studies might be a result of differences in patient and site characteristics, e.g., tissue biotype and buccal plate thickness. Therefore, the use of these interventions might be reserved for patients with moderate to high risk of esthetic complications.

The Effect of Flapless Surgery on Implant Survival and Marginal Bone Level: A Systematic Review and Meta-Analysis

BACKGROUND The clinical outcomes of implants placed using the flapless approach have not yet been systematically investigated. Hence, the present systematic review and meta-analysis aims to study the effect of the flapless technique on implant survival rates (SRs) and marginal bone levels (MBLs) compared with the conventional flap approach. METHODS An electronic search of five databases (from 1990 to March 2013), including PubMed, Ovid (MEDLINE), EMBASE, Web of Science, and Cochrane Central, and a hand search of peer-reviewed journals for relevant articles were performed. Human clinical trials with data on comparison of SR and changes in MBL between the flapless and conventional flap procedures, with at least five implants in each study group and a follow-up period of at least 6 months, were included. RESULTS Twelve studies, including seven randomized controlled trials (RCTs), one cohort study, one pilot study, and three retrospective case-controlled trials (CCTs), were included. The SR of each study was recorded, weighted mean difference (WMD) and confidence interval (CI) were calculated, and meta-analyses were performed for changes in MBL. The average SR is 97.0% (range, 90% to 100%) for the flapless procedure and 98.6% (range, 91.67% to 100%) for the flap procedure. Meta-analysis for the comparison of SR among selected studies presented a similar outcome (risk ratio = 0.99, 95% CI = 0.97 to 1.01, P = 0.30) for both interventions. Mean differences of MBL were retrieved from five RCTs and two retrospective CCTs and subsequently pooled into meta-analyses; however, none of the comparisons showed statistical significance. For RCTs, the WMD was 0.07, with a 95% CI of -0.05 to 0.20 (P = 0.26). For retrospective CCTs, the WMD was 0.23, with a 95% CI of -0.58 to 1.05 (P = 0.58). For the combined analysis, the WMD was 0.03, with a 95% CI of -0.11 to 0.18 (P = 0.67). The comparison of SR presented a low to moderate heterogeneity, but MBL presented a considerable heterogeneity among studies. CONCLUSION This systematic review revealed that the SRs and radiographic marginal bone loss of flapless intervention were comparable with the flap surgery approach.

Clinical outcomes of using lasers for peri-implantitis surface detoxification: a systematic review and meta-analysis.

UNLABELLED The aim of this systematic review is to compare the clinical outcomes of lasers with other commonly applied detoxification methods for treating peri-implantitis. An electronic search of four databases and a hand search of peer-reviewed journals for relevant articles were conducted. Comparative human clinical trials and case series with ≥ 6 months of follow-up in ≥ 10 patients with peri-implantitis treated with lasers were included. Additionally, animal studies applying lasers for treating peri-implantitis were also included. The included studies had to report probing depth (PD) reduction after the therapy. RESULTS Seven human prospective clinical trials and two animal studies were included. In four and three human studies, lasers were accompanied with surgical and non-surgical treatments, respectively. The meta-analyses showed an overall weighted mean difference of 0.00 mm (95% confidence interval = -0.18 to 0.19 mm) PD reduction between the laser and conventional treatment groups (P = 0.98) for non-surgical intervention. In animal studies, laser-treated rough-surface implants had a higher percentage of bone-to-implant contact than smooth-surface implants. In a short-term follow-up, lasers resulted in similar PD reduction when compared with conventional implant surface decontamination methods.

Influence of Soft Tissue Thickness on Peri-Implant Marginal Bone Loss: A Systematic Review and Meta-Analysis

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.

Tooth loss in molars with and without furcation involvement - a systematic review and meta-analysis.

BACKGROUND The aim of this study was to investigate risk of tooth loss in molars with furcation involvement (FI) based on initial diagnosis. MATERIALS AND METHODS A systematic search of the literature was conducted in Ovid Medline, Embase, LILACS and Cochrane Library for longitudinal studies with at least 3 years follow-up including measures of FI and data on tooth loss. RESULTS A total of 21 studies were included in the review, from an initial search of 1207 titles. The relative risk of tooth loss during maintenance therapy attributable to FI was 1.46 (95% CI = 0.99-2.15, p = 0.06) for studies up to 10 years and 2.21 (95% CI = 1.79-2.74, p < 0.0001) for studies with a follow-up of 10-15 years. A gradual increase in the risk of tooth loss was observed for molars with degree II and III FI. CONCLUSIONS The presence of FI approximately doubles the risk of tooth loss for molars maintained in supportive periodontal therapy for up to 10-15 years. However, most molars, even with grade III FI respond well to periodontal therapy, suggesting that every effort should be made to maintain these teeth when possible. Long-term studies reporting patient-reported outcomes are needed to substantiate this conclusion.

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.