Inmaculada Ortega-Oller

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.

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.

Prosthetic Abutment Height is a Key Factor in Peri-implant Marginal Bone Loss

In this study, we analyzed the influence of prosthetic abutment height on marginal bone loss (MBL) around implants in the posterior maxilla. In this retrospective cohort study, the radiographically determined MBL was related to the height of the abutments of internal conical connection implants at 6 and 18 months post-loading. Data were gathered on age, sex, bone substratum, smoking habit, history of periodontitis, and prosthetic features, among other variables. A linear mixed model was used for statistical analysis. The study included 131 patients receiving 315 implants. MBL rates at 6 and 18 months were mainly affected by the abutment height but were also significantly influenced by the bone substratum, periodontitis, and smoking habit. MBL rates were higher for prosthetic abutment < 2 mm vs. ≥ 2 mm, for periodontal vs. non-periodontal patients, for grafted vs. pristine bone, and for a heavier smoking habit. The abutment height is a key factor in MBL. MBL rates followed a non-linear trend, with a greater MBL rate during the first 6 months post-loading than during the next 12 months.

Bone Regeneration from PLGA Micro-Nanoparticles

Poly-lactic-co-glycolic acid (PLGA) is one of the most widely used synthetic polymers for development of delivery systems for drugs and therapeutic biomolecules and as component of tissue engineering applications. Its properties and versatility allow it to be a reference polymer in manufacturing of nano- and microparticles to encapsulate and deliver a wide variety of hydrophobic and hydrophilic molecules. It additionally facilitates and extends its use to encapsulate biomolecules such as proteins or nucleic acids that can be released in a controlled way. This review focuses on the use of nano/microparticles of PLGA as a delivery system of one of the most commonly used growth factors in bone tissue engineering, the bone morphogenetic protein 2 (BMP2). Thus, all the needed requirements to reach a controlled delivery of BMP2 using PLGA particles as a main component have been examined. The problems and solutions for the adequate development of this system with a great potential in cell differentiation and proliferation processes under a bone regenerative point of view are discussed.

Effect of barrier membranes on the outcomes of maxillary sinus floor augmentation: a meta-analysis of histomorphometric outcomes.

PURPOSE Sinus floor elevation via the lateral window approach represents a reliable technique for augmenting bone volume in the atrophic posterior maxilla. However, controversy remains regarding the effect of placement of a barrier membrane over the lateral window. This histomorphometric meta-analysis sought to clarify the effect of barrier membranes in lateral window sinus augmentation. MATERIALS AND METHODS An electronic search of three databases and a hand search in implant-related journals for studies published through January 2013 in the English language was conducted. Randomized controlled trials, prospective human clinical studies, retrospective investigations, and case series reporting histomorphometric results after sinus elevation using the lateral window approach with at least six patients and a minimum follow-up period of 6 months were included. RESULTS The initial search yielded 1,040 articles, of which 94 were further evaluated for eligibility. Finally, 37 studies were chosen and separated into membrane (group 1) and no-membrane (group 2) groups. Similar vital bone formation was found in both groups: 32.36% for group 1 and 33.07% for group 2. CONCLUSION Based does not influence the amount of vital bone formation after sinus augmentation. Additionally, the type of grafting material used and healing time did not influence the histomorphometric outcome.

Preterm birth and/or low birth weight are associated with periodontal disease and the increased placental immunohistochemical expression of inflammatory markers

UNLABELLED The objective of this study was to determine whether gynecological and periodontal clinical parameters and the immunohistochemical expression in placental chorionic villi of the markers cyclooxygenase-2 (COX-2), interleukin (IL)-1β, vascular endothelial growth factor receptor 1 (VEGFR1), podoplanin, and Heat Shock Protein 70 (HSP70) are associated with preterm birth (PB) and/or low birth weight (LBW) neonates. MATERIAL AND METHODS An observational case-control study was performed in 130 puerperal women: mothers of PB/LBW neonates (cases, n=65) and mothers of full-term normal-weight neonates (controls, n=65). Data were gathered from all participants on socio-demographic, gynecological, and periodontal variables and on placental immunohistochemical COX-2, IL-1β, VEGFR1, podoplanin, and HSP70 expression. RESULTS Among the 42 women with mild/moderate periodontitis or gingivitis, the studied periodontal variables were significantly worse and the placental COX-2 (p=0.043), HSP70 (p=0.001), IL-1β (p=0.001), VEGFR1 (p=0.032), and podoplanin (p=0.058) expressions were significantly higher in the cases than in the controls. In comparison to the mothers without periodontitis, only COX-2 (p=0.026) and VEGFR1 (p=0.005) expressions were significantly increased in those with the disease. Increased COX-2 values were detected in the women with a history of genitourinary infection (p=0.036), premature rupture of membrane (p=0.012), or drug treatment (p=0.050). CONCLUSIONS The etiology of preterm birth and/or low birth weight is multifactorial and involves consumption habits, social-health factors, and infectious episodes. These adverse pregnancy outcomes were associated with periodontitis and the increased placental expression of IL-1β, COX-2, VEGFR1, and HSP70.

Effect of rhBMP-2 upon maxillary sinus augmentation: a comprehensive review.

Purpose: The purpose of this review was to summarize the recent in vitro and in vivo research findings in areas where rhBMP-2 was used as a grafting material for sinus augmentation. Materials and Methods: An electronic literature search for relevant articles published in English was conducted in the PubMed database from February 1996 to August 2012. Randomized clinical trials or prospective human clinical and animal trials were included with the primary objective to compare and evaluate the effectiveness of rhBMP-2 for sinus augmentation. Results: A total of 3 human studies and 4 animal trials qualified the selection criteria that were included in this review. In humans, the selected studies indicated that rhBMP-2 induces new bone formation with comparable bone quality or amount of newly formed bone to that induced by autogenous bone graft. Furthermore, no differences have been reported between new bone induced by rhBMP-2 and native bone. Animal model studies also demonstrated regular bone formation induced by rhBMP-2, followed by normal maturation of new bone. Conclusion: All these studies demonstrate the osteoinductive and osteogenic capacity of rhBMP-2 and support it as an alternative for autogenous bone in sinus floor augmentation.

Sensitivity of resonance frequency analysis for detecting early implant failure: a case-control study.

PURPOSE The aim of this study was to test the sensitivity of the resonance frequency analysis for detecting early implant failure. MATERIALS AND METHODS In all, 3,786 implants placed from June 2007 to January 2013 were retrospectively evaluated. A total of 20 implants (in 20 patients) placed in pristine bone were found to have failed before loading. The implant stability quotient (ISQ) values were extracted from these 20 implants at baseline (immediate) and 4 months after placement (delayed). Simple linear regression, logistic regression, and two-way contingency tables were used to test for the relationships between ISQ values and early implant failure. RESULTS Immediate ISQ values were significantly related to failure (odds ratio [OR] = 4.27). Furthermore, the results of the second regression showed a significant relationship between ISQ at delayed measurement and implant failure (OR = 9.20). For immediate ISQ, it seems that the 73.7% correct classifications were obtained at the cost of an incorrect classification of 55% of the implant failures. However, for the delayed ISQ, 86.2% correct classifications were obtained at the cost of assuming that all implants will survive. CONCLUSION The present study showed that ISQ values are not reliable in predicting early implant failure. In addition, the real cutoff ISQ value to differentiate between success and early implant failure remains to be determined.

Effect of cantilevers for implant-supported prostheses on marginal bone loss and prosthetic complications: systematic review and meta-analysis.

PURPOSE The aim of this study was to conduct a systematic review and meta-analysis to evaluate the influence of cantilevers upon implant-supported fixed partial dentures on marginal bone loss (MBL) and prosthetic-related complications. MATERIALS AND METHODS An electronic literature search was conducted in the PubMed database by two reviewers (LTM and AM) for articles written in English from June 2003 to January 2013 that were prospective human clinical trials with the clear purpose of appraising the effect of implant-supported fixed partial prostheses on peri-implant bone level and prosthetic complications. Data from the selected studies were extracted to carry out the statistical analysis. RESULTS Following the method described earlier, from initial research of 643 studies, 4 human clinical studies met the inclusion criteria and provided enough data to include them in the present meta-analysis. For the overall data, the pooled weighted mean (WM) of the MBL was 0.72 mm (range, 0.49 to 1.10 mm), with a 95% confidence interval (CI) of 0.36 to 1.08 mm. For the chi-square test, P = .60, representing a low heterogeneity among studies. MBL around implant-supported restorations with and without cantilevers was not found to be significant between both groups. The weighted mean difference (WMD) was 0.10 mm (favoring the non-cantilever group), with a 95% CI = -0.18 to 0.39 mm (P = .47). For the chi-square test, P = .97, also indicating a low degree of heterogeneity between the studies. CONCLUSION The dearth of scientific evidence in this matter does not permit clear conclusions to be drawn. However, within the limitations, marginal bone loss does not seem to be influenced by the presence of cantilever extensions. Moreover, minor technical complications were found when a cantilever was present when compared to the control groups.

Cellular, Vascular, and Histomorphometric Outcomes of Solvent-Dehydrated vs Freeze-Dried Allogeneic Graft for Maxillary Sinus Augmentation: A Randomized Case Series.

PURPOSE The aim of this study was to compare solvent dehydrated human allograft (SDHA; Puros Allograft) and freeze-dried human allograft (FDHA; MinerOss) in order to determine if the allogeneic bone preservation process influences the amount of remaining particles and newly formed bone in maxillary sinus augmentation. MATERIALS AND METHODS Subjects requiring maxillary lateral sinus augmentation with ridge height < 5 mm were included in this study. Maxillary sinuses were randomly assigned to be grafted with a 1:1 ratio of cortical and cancellous bone, either SDHA or FDHA. In both groups, the graft material was mixed with autogenous bone graft at a ratio of 1:1. Morphologic and histomorphometric analyses were completed 6 months after the grafting procedure. RESULTS Thirty-four subjects were included in this study. All subjects showed similar demographic characteristics at baseline. Half of the sinuses were grafted with SDHA; the remaining half were grafted with FDHA. Histomorphometric analysis of bone core biopsy samples showed no statistically significant difference between the SDHA or FDHA allogeneic bone substitutes (P = .365), with a mean value of 39.54% ± 0.05% and 31.96% ± 0.08% of mineralized tissue for SDHA and FDHA, respectively. However, a slightly higher mean value of remaining particles was obtained for the FDHA compared with SDHA (18.91% ± 0.09% vs 8.65% ± 0.06%, respectively), although the difference was not statistically significant. Additionally, FDHA demonstrated statistically significantly higher osteoblast, fibroblast, and inflammatory cell numbers. CONCLUSION Regardless of the preservation process subtype, allogeneic bone grafting material, in combination with autogenous bone, was demonstrated to be effective for maxillary sinus augmentation bone by means of cellular, vascular, and histomorphometric behavior. Nonetheless, FDHA demonstrated higher cellularity compared to SDHA, suggesting accelerated turnover activity for the latter grafting material.