Evaluation of Collagen Membranes Coated with Testosterone and Alendronate to Improve Guided Bone Regeneration in Mandibular Bone Defects in Minipigs

Contains fulltext : 232819.pdf (Publisher’s version ) (Open Access)OBJECTIVES: The purpose of the present in vivo study was to evaluate whether pericard collagen membranes coated with ancillary amounts of testosterone and alendronate in a poly-lactic glycolic acid (PLGA) carrier as compared to uncoated membranes will improve early bone regeneration. MATERIAL AND METHODS: In each of 16 minipigs, four standardized mandibular intraosseous defects were made bilaterally. The defects were filled with Bio-Oss(®) granules and covered with a non-coated or coated membrane. Membranes were spray-coated with 4 layers of PLGA containing testosterone and alendronate resulting in 20, 50 or 125 μg/cm(2) of testosterone and 20 µg/cm(2) alendronate (F20, F50, F125). Non-coated membranes served as controls (F0). Animals were sacrificed at 6 and 12 weeks after treatment. Qualitative and quantitative histological evaluations of bone regeneration were performed. Differences between groups were assessed by paired Student's t-test. RESULTS: Light microscopical analysis showed new bone formation that was in close contact with the Bio-Oss(®) surface without an intervening non-mineralized tissue layer. Histomorphometric analysis of newly formed bone showed a significant 20% increase in area in the F125 coated membrane treated defects (40 [SD 10]%) compared to the F0 treated defects after 6 weeks (33 [SD 10]%, P = 0.013). At week 12, the total percentage of new bone was increased compared to week 6, but no increase in newly formed bone compared to F0 was observed. CONCLUSIONS: The data from this in vivo study indicate that F125 collagen membranes coated with testosterone and alendronate resulted in superior bone formation (+24%) when normalized to control sites using uncoated membranes

Biomaterial-based possibilities for managing peri-implantitis

Contains fulltext : 218148.pdf (publisher's version ) (Open Access)Peri-implantitis is an inflammatory disease of hard and soft tissues around osseointegrated implants, followed by a progressive damage of alveolar bone. Oral microorganisms can adhere to all types of surfaces by the production of multiple adhesive factors. Inherent properties of materials will influence not only the number of microorganisms, but also their profile and adhesion force onto the material surface. In this perspective, strategies to reduce the adhesion of pathogenic microorganisms on dental implants and their components should be investigated in modern rehabilitation concepts in implant dentistry. To date, several metallic nanoparticle films have been developed to reduce the growth of pathogenic bacteria. However, the main drawback in these approaches is the potential toxicity and accumulative effect of the metals over time. In view of biological issues and in attempt to prevent and/or treat peri-implantitis, biomaterials as carriers of antimicrobial substances have attracted special attention for application as coatings on dental implant devices. This review will focus on biomaterial-based possibilities to prevent and/or treat peri-implantitis by describing concepts and dental implant components suitable for engagement in preventing and treating this disease. Additionally, we raise important criteria referring to the geometric parameters of dental implants and their components, which can directly affect peri-implant tissue conditions. Finally, we overview currently available biomaterial systems that can be used in the field of oral implantology

Innovative implant design for continuous implant stability: A mechanical and histological experimental study in the iliac crest of goats

OBJECTIVES: this in vivo study reports on mechanical torque data as well as the biological evaluation up to 6 weeks after placement of implants with a unique wide knife thread design in a goat iliac crest model. We hypothesized that implants with this thread design would show substantial primary stability at a continuous level toward secondary stability. METHODS: 64 MegaGen Anyridge® implants were used with diameters 3.5 mm, 4.0 mm, 5.0 mm and 6.0 mm (n = 8). Implants were placed monocortically in the iliac crest of 16 healthy female Saanen goats, both on the right (for torque measurements) and left side (for histology/-morphometry). Torque-in at implant installation and torque-out at 2 and 6 weeks of implantation was measured, as well as bone-to-implant contact (BIC) and bone-area between the screw threads (BA). RESULTS: Histology showed intimate bone-to-implant contact with a maturating trabecular structure between 2 and 6 weeks. Torque values showed a dependency on implant diameter. For all implant diameters, torque-in values were similar to torque-out values at 2 weeks. At 6 weeks however, all torque-out values were significantly increased. BIC and BA percentages showed similar values for all diameters at both 2 and 6 weeks. CONCLUSIONS: These results prove the absence of a lag-phase in implant stability for MegaGen Anyridge® implants in the goat iliac crest model. The increased torque-out values at 6 weeks without increasing BIC and BA percentages correlate with the observed maturation of bone-to-implant contact quality over time. CLINICAL SIGNIFICANCE: It is a challenge to optimize implants with continuous primary stability and rapid transition into secondary stability to minimize the duration of the lag-phase. The results of this study prove the absence of a lag-phase in implant stability for MegaGen Anyridge® implants. Consequently, the data from this work are important for the treatment of individual patients 'translating' these findings into clinical implant procedures

Comparison of different surface modifications for titanium implants installed into the goat iliac crest.

OBJECTIVES: This in vivo study with implants installed in the goat iliac crest was performed to determine whether the biological and mechanical properties of the bone-to-implant interface are influenced by (i) the type of implant anchorage (i.e., mono- vs. bicortical placement), and (ii) the presence of a bioactive hydroxyapatite (HA) or composite HA/bioactive glass (BG) coatings. MATERIALS AND METHODS: A total of 96 titanium (Ti) implants w/- coatings (Ti, Ti-HA & Ti-HABG; n = 8) were mono- or bicortically placed in the iliac crest of eight goats. At installation and after 4 weeks, implant stability was determined using insertion and removal torque testing (ITQ & RTQ). The peri-implant bone response was histologically and histomorphometrically evaluated by means of bone-to-implant contact (BIC%) and bone area (BA%). RESULTS: Monocortical implants demonstrated significantly lower RTQ values in comparison to ITQ values, whereas for bicortical implant placement RTQ and ITQ were similar. Further, mean RTQ values for monocortical implants were significantly lower in comparison to bicortical implants. Histomorphometrical evaluation demonstrated higher BIC% and BA% for bicortical implants compared to monocortical implants. For bicortical implants, BA% in the inner peri-implant region (0-500 mum) was significantly higher compared to the middle (500-1000 mum) and outer (1000-1500 mum) region. Also, a significant correlation was observed for monocortical implants between RTQ and BIC% and BA%. For surface modifications, no significant differences were found in ITQ and RTQ, for neither mono- nor bicortical implants. Histomorphometrically, HABG-coated implants demonstrated significantly higher BIC% compared to GAE surfaces for both mono- and bicortical implants. Bicortical HA-coated implants revealed significant higher BA% in the inner peri-implant region (0-500 mum) in comparison to bicortical GAE implants. CONCLUSIONS: This study demonstrated that bicortical implant placement beneficially affects implant stability during the early phase of osseointegration. A significant correlation between removal torque and bone-to-implant contact and bone area for monocortical implants was observed, but not for bicortical implants. Therefore, histomorphometrical data should be interpreted with caution to predict the biomechanical implant fixation of bone implants over time. Regarding surface modifications, in the present implantation model, the addition of BG to an RF magnetron sputtered HA coating enhanced the biological behavior of the coating compared to grit-blasted/acid-etched implants

A systematic review on the long-term success of calcium phosphate plasma-spray-coated dental implants

The objectives of the current review were (1) to systematically appraise, and (2) to evaluate long-term success data of calcium phosphate (CaP) plasma-spray-coated dental implants in clinical trials with at least 5 years of follow-up. To describe the long-term efficacy of functional implants, the outcome variables were (a) percentage annual complication rate (ACR) and (b) cumulative success rate (CSR), as presented in the selected articles. The electronic search yielded 645 titles. On the basis of the inclusion criteria, 8 studies were finally included. The percentage of implants in function after the first year was estimated to be 98.4 % in the maxilla and 99.2 % in the mandible. The estimates of the weighted mean ACR-percentage increased over the years up to 2.6 (SE 0.7) during the fifth year of function for the maxilla and to 9.4 (SE 8.4) for the mandible in the tenth year of function. After 10 years, the mean percentage of successful implants was estimated to be 71.1 % in the maxilla and 72.2 % in the mandible. The estimates seem to confirm the proposed, long-term progressive bone loss pattern of CaP-ceramic-coated dental implants. Within the limits of this meta-analytic approach to the literature, we conclude that: (1) published long-term success data for calcium phosphate plasma-spray-coated dental implants are limited, (2) comparison of the data is difficult due to differences in success criteria among the studies, and (3) long-term CSRs demonstrate very weak evidence for progressive complications around calcium phosphate plasma-spray-coated dental implants

A comparative study of the bone contact to zirconium and titanium implants after 8 weeks of implantation in rabbit femoral condyles

Contains fulltext : 183752.pdf (Publisher’s version ) (Open Access

[Evidence-based clinical practice guidelines in oral care 2: process and content of evidence-based guideline development]

Item does not contain fulltextIn 2014, an advisory report was published by a national working committee concerning how the current, applied method of evidence-based guideline development in healthcare can be used in oral care in a national guideline programme. In an independent Institute of Knowledge Translation in Oral Care, as yet to be established, primary and secondary oral care providers will participate in the programme in order to improve the quality of oral care in the Netherlands. With the launching of the Institute of Knowledge Translation in Oral Care, clinical guideline development will have the benefit of a structural approach, in which 3 successive steps can be distinguished: preparation, development and authorisation. In each of these steps, oral care providers and associations will be actively involved. In this way the aim is to give as much consideration as possible to the needs of those in the field of oral care in the choice of topics for guideline development and to secure the specific character of oral care in the actual establishment of guidelines for clinical practice. Publisher: Abstract available from the publisher. du

Porous titanium scaffolds with injectable hyaluronic acid-DBM gel for bone substitution in a rat critical-sized calvarial defect model

Item does not contain fulltextDemineralized bone matrix (DBM) is an allograft bone substitute used for bone repair surgery to overcome drawbacks of autologous bone grafting, such as limited supply and donor-site comorbidities. In view of different demineralization treatments to obtain DBM, we examined the biological performance of two differently demineralized types of DBM, i.e. by acidic treatment using hydrochloric acid (HCl) or treatment with the chelating agent ethylene diamine tetra-acetate (EDTA). First, we evaluated the osteo-inductive properties of both DBMs by implanting the materials subcutaneously in rats. Second, we evaluated the effects on bone formation by incorporating DBM in a hyaluronic acid (HA) gel to fill a porous titanium scaffold for use in a critical-sized calvarial defect model in 36 male Wistar rats. These porous titanium scaffolds were implanted empty or filled with HA gel containing either DBM HCl or DBM EDTA. Ectopically implanted DBM HCl and DBM EDTA did not induce ectopic bone formation over the course of 12 weeks. For the calvarial defects, mean percentages of newly formed bone at 2 weeks were significantly higher for Ti-Empty compared to Ti-HA + DBM HCl, but not compared to Ti-HA + DBM EDTA. Significant temporal bone formation was observed for Ti-Empty and Ti-HA + DBM HCl, but not for Ti-HA + DBM EDTA. At 8 weeks there were no significant differences in values of bone formation between the three experimental constructs. In conclusion, these results showed that, under the current experimental conditions, neither DBM HCl nor DBM EDTA possess osteo-inductive properties. Additionally, in combination with an HA gel loaded in a porous titanium scaffold, DBM HCl and DBM EDTA showed similar amounts of new bone formation after 8 weeks, which were lower than using the empty porous titanium scaffold. Copyright (c) 2016 John Wiley & Sons, Ltd