Alberto Monje

Are Short Dental Implants (<10 mm) Effective? A Meta-Analysis on Prospective Clinical Trials

BACKGROUND This study aims to compare the survival rate of short (<10 mm) and standard (≥10 mm) rough-surface dental implants under functional loading. METHODS An electronic literature search using PubMed and Medline databases was conducted. Prospective clinical human trials, published in English from January 1997 to July 2011, that examined dental implants of <10 mm with a 12-month follow-up were included in this meta-analysis. The following data were retrieved from the included articles: the number of implants, implant dimensions, implant locations, types of prostheses, follow-up periods, and implant survival rates. Kaplan-Meier survival estimates and the hazard rates were analyzed and compared between short and standard implants. RESULTS Thirteen studies were selected, examining 1,955 dental implants, of which 914 were short implants. Short dental implants had an estimated survival rate of 88.1% at 168 months, when standard dental implants had a similar estimated survival rate of 86.7% (P = 0.254). The peak failure rate of short dental implants was found to occur between 4 and 6 years of function. This occurred at an earlier time point compared with standard dental implants, where the peak failure rate occurred between 6 and 8 years of function. CONCLUSIONS This study shows that in the long term, implants of <10 mm are as predictable as longer implants. However, they fail at an earlier stage compared with standard implants.

Impact of Maintenance Therapy for the Prevention of Peri-implant Diseases: A Systematic Review and Meta-analysis.

At the present time, peri-implantitis has become a global burden that occurs with a frequency from 1% to 47% at implant level. Therefore, we aimed herein at assessing the impact of peri-implant maintenance therapy (PIMT) on the prevention of peri-implant diseases. Electronic and manual literature searches were conducted by 3 independent reviewers using several databases, including MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Oral Health Group Trials Register, for articles up to June 2015 without language restriction. Articles were included if they were clinical trials aimed at demonstrating the incidence of peri-implant diseases under a strict regime or not of PIMT. Implant survival and failure rate were studied as secondary outcomes. A meta-analysis was conducted to evaluate the influence of PIMT and other reported variables upon peri-implant diseases. Thirteen and 10 clinical trials were included in the qualitative and quantitative analysis, respectively. Mucositis was affected by history of periodontitis and mean PIMT at implant and patient levels, respectively. Similarly, significant effects of history of periodontal disease were obtained for peri-implantitis for both implant and patient levels. Furthermore, mean PIMT interval was demonstrated to influence the incidence of peri-implantitis at implant but not patient level. PIMT interval showed significance at both levels. For implant survival, implants under PIMT have 0.958 the incident event than those with no PIMT. Within the limitations of the present systematic review, it can be concluded that implant therapy must not be limited to the placement and restoration of dental implants but to the implementation of PIMT to potentially prevent biologic complications and hence to heighten the long-term success rate. Although it must be tailored to a patient’s risk profiling, our findings suggest reason to claim a minimum recall PIMT interval of 5 to 6 mo. Additionally, it must be stressed that even in the establishment of PIMT, biologic complications might occur. Thus, patient-, clinical-, and implant-related factors must be thoroughly explored.

Marginal bone loss as success criterion in implant dentistry: beyond 2 mm.

AIM The aim of this study was to analyze marginal bone loss (MBL) rates around implants to establish the difference between physiological bone loss and bone loss due to peri-implantitis. MATERIALS AND METHODS Five hundred and eight implants were placed in the posterior maxilla in 208 patients. Data were gathered on age, gender, bone substratum (grafted or pristine), prosthetic connection, smoking and alcohol habits, and previous periodontitis. MBL was radiographically analyzed in three time frames (5 months post-surgery and at 6 and 18 months post-loading). Nonparametric receiver operating curve (ROC) analysis and mixed linear model analysis were used to determine whether implants could be classified as high or low bone loser type (BLT) and to establish the influence of this factor on MBL rates. RESULTS Marginal bone loss rates were significantly affected by BLT, connection type, bone substratum, and smoking. Bone loss rates at 18 months were associated with initial bone loss rates: 96% of implants with an MBL of >2 mm at 18 months had lost 0.44 mm or more at 6 months post-loading. CONCLUSION Implants with increased MBL rates at early stages (healing and immediate post-loading periods) are likely to reach MBL values that compromise their final outcome. Initial (healing, immediate post-loading) MBL rates around an implant of more than 0.44 mm/year are an indication of peri-implant bone loss progression.

Tissue Engineering for Bone Regeneration and Osseointegration in the Oral Cavity

OBJECTIVE The focus of this review is to summarize recent advances on regenerative technologies (scaffolding matrices, cell/gene therapy and biologic drug delivery) to promote reconstruction of tooth and dental implant-associated bone defects. METHODS An overview of scaffolds developed for application in bone regeneration is presented with an emphasis on identifying the primary criteria required for optimized scaffold design for the purpose of regenerating physiologically functional osseous tissues. Growth factors and other biologics with clinical potential for osteogenesis are examined, with a comprehensive assessment of pre-clinical and clinical studies. Potential novel improvements to current matrix-based delivery platforms for increased control of growth factor spatiotemporal release kinetics are highlighting including recent advancements in stem cell and gene therapy. RESULTS An analysis of existing scaffold materials, their strategic design for tissue regeneration, and use of growth factors for improved bone formation in oral regenerative therapies results in the identification of current limitations and required improvements to continue moving the field of bone tissue engineering forward into the clinical arena. SIGNIFICANCE Development of optimized scaffolding matrices for the predictable regeneration of structurally and physiologically functional osseous tissues is still an elusive goal. The introduction of growth factor biologics and cells has the potential to improve the biomimetic properties and regenerative potential of scaffold-based delivery platforms for next-generation patient-specific treatments with greater clinical outcome predictability.

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.

Influence of Crown/Implant Ratio on Marginal Bone Loss: A Systematic Review

BACKGROUND With the increased use of short dental implants (<10 mm), a high crown/implant (C/I) ratio has become a common finding. However, the effect of the C/I ratio on the marginal bone loss (MBL) has not yet been examined extensively. Hence, the aim of the present systematic review is to explore the influence of the C/I ratio on the success rate and MBL of dental implants. METHODS Three electronic databases (PubMed, Ovid MEDLINE, and Cochrane Central) and a manual search for human trials with a minimal follow-up of 6 months are used for the present study. A statistical analysis of the influence of the C/I ratio was performed on the peri-implant MBL while considering follow-up period, type of implants, implant connection, and technical and biologic complications. RESULTS One hundred ninety-six potential articles were identified on the selected databases. Only 57 articles were selected for full-text evaluation. According to the inclusion criteria, a total of 13 articles were included in this systematic review. A significant negative association between the C/I ratio and the MBL was found (P = 0.012). However, no statistically significant difference was found (P >0.15) for potential effects regarding the observation period, the type of implant connection, or between both methods of evaluating the C/I ratio. CONCLUSIONS Within the limitations of the present study, the C/I ratio of implant-supported restorations has an effect on peri-implant marginal bone level. Within the range of 0.6/1 to 2.36/1, the higher the C/I ratio, the less the peri-implant MBL.

Effect of the Timing of Restoration on Implant Marginal Bone Loss: A Systematic Review

BACKGROUND The advancement in implant dentistry has allowed shortened treatment time by restoring the implants earlier. Whether the timing of restoration has an impact on implant marginal bone level has not been systematically analyzed. The aim of this study is to compare marginal bone loss (MBL) between implants that were restored with the following protocols: 1) immediate restoration/loading (IR/L); 2) early loading (EL); and 3) conventional loading (CL). METHODS An electronic literature search from three databases (until November 2011) and a hand search in implant-related journals were conducted. Clinical human studies in English language that had reported a comparison of MBL between implants with IR/L, EL, or CL with ≥12-month follow-up were included. In addition, the minimal number of implants had to be 10 for each group. Implants with both immediate placement (IP) and delayed placement (DP) were included and analyzed separately. An assessment of the publication bias for the included randomized clinical trials (RCTs) was performed. RESULTS The initial search resulted in 1,640 articles, of which 27 articles in full text were further evaluated for eligibility. Finally, 11 studies (eight RCTs, two controlled clinical trials, and one retrospective study) were qualified and classified into four groups: 1) IR/L + DP versus CL + DP (n = 6 articles); 2) IR + DP versus EL + DP (n = 2 articles); 3) EL + DP versus CL + DP (n = 1 article); and (4) IL + IP versus CL + IP (n = 2 articles). A meta-analysis performed for group 1 showed 0.09 mm (95% confidence interval = -0.27 to 0.09 mm) difference in the mean MBL, favoring the IR/L protocol but without significant difference (P = 0.33). No significant difference in MBL was found for groups 2 through 4 after adjusting for the implant placement level. The eight RCTs were determined to be at moderate-to-high risk of publication bias. CONCLUSIONS This meta-analysis does not show an effect of the timing of restorations on implant MBL. The selection of restoration protocols should be based on factors other than MBL.

Integration of 3D Printed and Micropatterned Polycaprolactone Scaffolds for Guidance of Oriented Collagenous Tissue Formation In Vivo

Scaffold design incorporating multiscale cues for clinically relevant, aligned tissue regeneration has potential to improve structural and functional integrity of multitissue interfaces. The objective of this preclinical study is to develop poly(ε-caprolactone) (PCL) scaffolds with mesoscale and microscale architectural cues specific to human ligament progenitor cells and assess their ability to form aligned bone-ligament-cementum complexes in vivo. PCL scaffolds are designed to integrate a 3D printed bone region with a micropatterned PCL thin film consisting of grooved pillars. The patterned film region is seeded with human ligament cells, fibroblasts transduced with bone morphogenetic protein-7 genes seeded within the bone region, and a tooth dentin segment positioned on the ligament region prior to subcutaneous implantation into a murine model. Results indicate increased tissue alignment in vivo using micropatterned PCL films, compared to random-porous PCL. At week 6, 30 μm groove depth significantly enhances oriented collagen fiber thickness, overall cell alignment, and nuclear elongation relative to 10 μm groove depth. This study demonstrates for the first time that scaffolds with combined hierarchical mesoscale and microscale features can align cells in vivo for oral tissue repair with potential for improving the regenerative response of other bone-ligament complexes.

On the Feasibility of Utilizing Allogeneic Bone Blocks for Atrophic Maxillary Augmentation

Purpose. This systematic review was aimed at assessing the feasibility by means of survival rate, histologic analysis, and causes of failure of allogeneic block grafts for augmenting the atrophic maxilla. Material and Methods. A literature search was conducted by one reviewer in several databases. Articles were included in this systematic review if they were human clinical trials in which outcomes of allogeneic bone block grafts were studied by means of survival rate. In addition other factors were extracted in order to assess their influence upon graft failure. Results. Fifteen articles fulfilled the inclusion criteria and subsequently were analyzed in this systematic review. A total of 361 block grafts could be followed 4 to 9 months after the surgery, of which 9 (2.4%) failed within 1 month to 2 months after the surgery. Additionally, a weighed mean 4.79 mm (95% CI: 4.51–5.08) horizontal bone gain was computed from 119 grafted sites in 5 studies. Regarding implant cumulative survival rate, the weighed mean was 96.9% (95% CI: 92.8–98.7%), computed from 228 implants over a mean follow-up period of 23.9 months. Histologic analysis showed that allogeneic block grafts behave differently in the early stages of healing when compared to autogenous block grafts. Conclusion. Atrophied maxillary reconstruction with allogeneic bone block grafts represents a reliable option as shown by low block graft failure rate, minimal resorption, and high implant survival rate.

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.