Abstract Osteogenic agents, such as bone morphogenetic protein-2 (BMP-2), can stimulate the degradation as well as the formation of bone. Hence, they could impair the osteoconductivity of ...functionalized implant surfaces. We assessed the effects of BMP-2 and its mode of delivery on the osteoconductivity of dental implants with either a naked titanium surface or a calcium-phosphate-coated one. The naked titanium surface bore adsorbed BMP-2, whilst the coated one bore incorporated, adsorbed, or incorporated and adsorbed BMP-2. The implants were inserted into the maxillae of adult miniature pigs. The volume of bone deposited within a defined “osteoconductive” (peri-implant) space, and bone coverage of the implant surface delimiting this space, were estimated morphometrically 1–3 weeks later. After 3 weeks, the volume of bone deposited within the osteoconductive space was highest for coated and uncoated implants bearing no BMP-2, followed by coated implants bearing incorporated BMP-2; it was lowest for coated implants bearing only adsorbed BMP-2. Bone-interface coverage was highest for coated implants bearing no BMP-2, followed by coated implants bearing either incorporated, or incorporated and adsorbed BMP-2; it was lowest for uncoated implants bearing adsorbed BMP-2. Hence, the osteoconductivity of implant surfaces can be significantly modulated by BMP-2 and its mode of delivery.
The aim of this 3-year, randomized clinical trial (RCT) in split-mouth design was to explore the clinical survival of a Bis-GMA-free pit and fissure sealant (Helioseal F Plus) in comparison to a ...control material (Helioseal F). The initial population consisted of 92 adolescents. Follow-ups took place after one year (N = 85), two years (N = 82) and three years (N = 76) after application. At each examination, sealant retention and the presence of caries were recorded. The statistical analysis included the calculation of Kaplan–Meier survival curves, log-rank tests and a Cox proportional hazard regression model. No adverse events were documented. The proportion of completely intact sealants and those with minimal loss was almost identical in both groups, at 84.3% (Helioseal F; 113/134) and 81.7% (Helioseal F Plus; 107/131) after three years of observation. The regression analysis revealed an operator dependency, but no significant differences were found between the materials, the study centers, the chosen isolation technique, patient age or sex. After 3 years, 91.7% and 100.0% of all molars were free of non-cavitated carious lesions or carious cavities, respectively. It can be concluded that the new fissure sealing material can be considered as at least equivalent in terms of survival and retention behavior compared to the predecessor material.
Objectives: To investigate the influence of protein incorporation on the resistance of biomimetic calcium‐phosphate coatings to the shear forces that are generated during implant insertion.
Materials ...and Methods: Thirty‐eight standard (5 × 13 mm) Osseotite® implants were coated biomimetically with a layer of calcium phosphate, which either lacked or bore a co‐precipitated (incorporated) depot of the model protein bovine serum albumin (BSA). The coated implants were inserted into either artificial bone (n=18) or the explanted mandibles of adult pigs (n=12). The former set‐up was established for the measurement of torque and of coating losses during the insertion process. The latter set‐up was established for the histological and histomorphometric analysis of the fate of the coatings after implantation.
Results: BSA‐bearing coatings had higher mean torque values than did those that bore no protein depot. During the insertion process, less material was lost from the former than from the latter type of coating. The histological and histomorphometric analysis revealed fragments of material to be sheared off from both types of coating at vulnerable points, namely, at the tips of the threads. The sheared‐off fragments were retained within the peri‐implant space.
Conclusion: The incorporation of a protein into a biomimetically prepared calcium‐phosphate coating increases its resistance to the shear forces that are generated during implant insertion. In a clinical setting, the incorporated protein would be an osteogenic agent, whose osteoinductive potential would not be compromised by the shearing off of coating material, and the osteoconductivity of an exposed implant surface would not be less than that of a coated one.
To cite this article:
Hägi TT, Enggist L, Michel D, Ferguson SJ, Liu Y, Hunziker EB. Mechanical insertion properties of calcium‐phosphate implant coatings. Clin. Oral Impl. Res. 21, 2010; 1214–1222. doi: 10.1111/j.1600‐0501.2010.01916.x
Matrilins are oligomeric extracellular matrix adaptor proteins mediating interactions between collagen fibrils and other matrix constituents. All four matrilins are expressed in cartilage and ...mutations in the human gene encoding matrilin-3 (MATN3) are associated with different forms of chondrodysplasia. Surprisingly, however, Matn3-null as well as Matn1- and Matn2-null mice do not show an overt skeletal phenotype, suggesting a dominant negative pathomechanism for the human disorders and redundancy/compensation among the family members in the knock-out situation. Here, we show that mice lacking both matrilin-1 and matrilin-3 develop an apparently normal skeleton, but exhibit biochemical and ultrastructural abnormalities of the knee joint cartilage. At the protein level, an altered SDS-PAGE band pattern and a clear up-regulation of the homotrimeric form of matrilin-4 were evident in newborn Matn1/Matn3 and Matn1 knock-out mice, but not in Matn3-null mice. The ultrastructure of the cartilage matrix after conventional chemical fixation was grossly normal; however, electron microscopy of high pressure frozen and freeze-substituted samples, revealed two consistent observations: 1) moderately increased collagen fibril diameters throughout the epiphysis and the growth plate in both single and double mutants; and 2) increased collagen volume density in Matn1-/-/Matn3-/- and Matn3-/- mice. Taken together, our results demonstrate that matrilin-1 and matrilin-3 modulate collagen fibrillogenesis in cartilage and provide evidence that biochemical compensation might exist between matrilins.
Objectives
The aim of this randomized clinical trial (RCT) was to explore the clinical survival of a new, Bis-GMA-free pit and fissure sealant (Helioseal F Plus) in comparison to an established ...control material (Helioseal F).
Material and methods
This in vivo study was designed as a prospective, 2-year, two-centre RCT with a split-mouth design. The initial study population consisted of 92 adolescents who were followed up 1 month (
N
= 89), 6 months (
N
= 88), 1 year (
N
= 85) and 2 years (
N
= 82) after sealant application. The attrition rate was 10.9% after 2 years. At each examination, the sealant retention and presence of caries were recorded. The statistical analysis included the calculation of Kaplan–Meier survival curves, log-rank tests and a Cox proportional hazard regression model.
Results
No adverse events during the application or any of the follow-up visits were documented. The proportion of completely intact sealants and those with minimal loss was almost identical in both groups at 85.9% (Helioseal F Plus) and 86.5% Helioseal F) after 2 years of observation. The regression analysis revealed operator dependency; no significant differences were found between the materials, the study centres, the chosen isolation technique and patient age or sex.
Conclusion
The newly developed sealant can be evaluated as at least equivalent in terms of survival and retention behaviour compared to the established control material.
Clinical relevance
The new sealant can be recommended for clinical use. With respect to the material properties (Bis-GMA-free, less light polymerisation time and better thixotropic behaviour), it offers additional advantages with clinical relevance.
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