| 1. |
- Anchieta, Rodolfo B., et al.
(author)
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Mechanical Property Assessment of Bone Healing around a Titanium-Zirconium Alloy Dental Implant
- 2014
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In: Clinical Implant Dentistry and Related Research. - : John Wiley & Sons. - 1523-0899 .- 1708-8208. ; 16:6, s. 913-919
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Journal article (peer-reviewed)abstract
- BackgroundIt has been reported that titanium-zirconium alloy with 13-17% zirconium (TiZr1317) implants show higher biomechanical stability and bone area percentage relative to commercially pure titanium (cpTi) grade 4 fixtures. PurposeThis study aimed to determine whether the higher stability for TiZr1317 implants is associated with higher mechanical properties of remodeling bone in the areas around the implants. Materials and MethodsThis study utilized 36 implants (n=18: TiZr1317, n=18: cpTi), which were placed in the healed ridges of the mandibular premolar and first molar of 12 mini pigs (n=3 implants/animal). After 4 weeks in vivo, the samples were retrieved, and resin-embedded histologic sections of approximately 100m in thickness were prepared. In order to determine the nanomechanical properties, nanoindentation (n=30 tests/specimen) was performed on the bone tissue of the sections under wet conditions with maximum load of 300N (loading rate: 60N/s). ResultsThe mean (standard deviation) elastic modulus (E) and hardness (H) for the TiZr1317 group were 2.73 +/- 0.50GPa and 0.116 +/- 0.017GPa, respectively. For the cpTi group, values were 2.68 +/- 0.51GPa and 0.110 +/- 0.017GPa for E and H, respectively. Although slightly higher mechanical properties values were observed for the TiZr1317 implants relative to the cpTi for both elastic modulus and hardness, these differences were not significant (E=p>0.75; H=p>0.59). ConclusionsThe titanium-zirconium alloy used in this study presented similar degrees of nanomechanical properties to that of the cpTi implants.
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| 2. |
- Galli, Silvia, et al.
(author)
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The effect of osteotomy dimension on osseointegration to resorbable media-treated implants : a study in the sheep
- 2015
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In: Journal of biomaterials applications. - : Sage Publications. - 0885-3282 .- 1530-8022. ; 29:8, s. 1068-1074
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Journal article (peer-reviewed)abstract
- The drilling technique and the surface characteristics are known to influence the healing times of oral implants. The influence of osteotomy dimension on osseointegration of microroughned implant surfaces treated with resorbable blasting media was tested in an in vivo model. Ninety-six implants (ø4.5 mm, 8 mm in length) with resorbable blasting media-treated surfaces were placed in the ileum of six sheep. The final osteotomy diameters were 4.6mm (reamer), 4.1mm (loose), 3.7mm (medium), and 3.2mm (tight). After three and six weeks healing, the implants were biomechanically tested and histologically evaluated. Statistical analysis was performed using Page L trend test for ordered and paired sample and linear regression, with significance level at p < 0.05. An overall increase in all dependent variables was observed with the reduction of osteotomy diameter. In addition, all osseointegration scores increased over time. At three weeks, the retention was significantly higher for smaller osteo- tomies. The histological sections depicted intimate contact of bone with all the implant surfaces and osteoblast lines were visible in all sections. The resorbable blasting media microroughed surfaces achieved successful osseointegration for all the instrumentation procedures tested, with higher osseointegration scores for the high insertion torque group.
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| 3. |
- Jimbo, Ryo, et al.
(author)
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Histomorphometry and bone mechanical property evolution around different implant systems at early healing stages : an experimental study in dogs
- 2013
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In: Implant Dentistry. - : Lamy, Wolters Kluwer. - 1056-6163 .- 1538-2982. ; 22:6, s. 596-603
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Journal article (peer-reviewed)abstract
- PURPOSE: Commercial implants differ at macro-, micro-, and nanolevels, which makes it difficult to distinguish their effect on osseointegration. The aim of this study was to evaluate the early integration of 5 commercially available implants (Astra OsseoSpeed, Straumann SLA, Intra-Lock Blossom Ossean, Nobel Active, and OsseoFix) by histomorphometry and nanoindentation. MATERIALS AND METHODS: Implants were installed in the tibiae of 18 beagle dogs. Samples were retrieved at 1, 3, and 6 weeks (n = 6 for each time point) and were histologically and nanomechanically evaluated. RESULTS: The results presented that both time (P < 0.01) and implant system and time interaction (P < 0.02) significantly affected the bone-to-implant contact (BIC). At 1 week, the different groups presented statistically different outcomes. No significant changes in BIC were noted thereafter. There were no significant differences in rank elastic modulus (E) or in rank hardness (H) for time (E: P > 0.80; H: P > 0.75) or implant system (E: P > 0.90; H: P > 0.85). CONCLUSIONS: The effect of different implant designs on osseointegration was evident especially at early stages of bone healing.
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| 4. |
- Jimbo, Ryo, et al.
(author)
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The Effect of Brain-Derived Neurotrophic Factor on Periodontal Furcation Defects
- 2014
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In: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 9:1
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Journal article (peer-reviewed)abstract
- This study aimed to observe the regenerative effect of brain-derived neurotrophic factor (BDNF) in a non-human primate furcation defect model. Class II furcation defects were created in the first and second molars of 8 non-human primates to simulate a clinical situation. The defect was filled with either, Group A: BDNF (500 mu g/ml) in high-molecular weight-hyaluronic acid (HMW-HA), Group B: BDNF (50 mu g/ml) in HMW-HA, Group C: HMW-HA acid only, Group D: empty defect, or Group E: BDNF (500 mu g/ml) in saline. The healing status for all groups was observed at different time-points with micro computed tomography. The animals were euthanized after 11 weeks, and the tooth-bone specimens were subjected to histologic processing. The results showed that all groups seemed to successfully regenerate the alveolar buccal bone, however, only Group A regenerated the entire periodontal tissue, i.e., alveolar bone, cementum and periodontal ligament. It is suggested that the use of BDNF in combination with a scaffold such as the hyaluronic acid in periodontal furcation defects may be an effective treatment option.
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| 5. |
- Jimbo, Ryo, et al.
(author)
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The effect of different surgical drilling procedures on full laser-etched microgrooves surface-treated implants : an experimental study in sheep
- 2014
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In: Clinical Oral Implants Research. - : John Wiley & Sons. - 0905-7161 .- 1600-0501. ; 25:9, s. 1072-1077
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Journal article (peer-reviewed)abstract
- ObjectivesTo evaluate the influence of instrumentation technique on the early osseointegration histomorphometrics and biomechanical fixation of fully laser-etched microgrooves implant surfaces in a sheep model. Material and MethodsSix sheep were subjected to bilateral hip surgeries 3 and 6weeks before euthanasia. A total of 48 implants (empty set4.5mm, 8mm in length) were distributed among four sites (8 per animal) and placed in bone sites drilled to 4.6mm (reamer), 4.1mm (loose), 3.7mm (medium) and 3.2mm (tight) in diameter. After healing, the animals were euthanized and half of the implants were biomechanically tested, while the remainder was subjected to non-decalcified histologic processing. The histomorphometric parameters assessed were bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). Statistical analysis was performed using a mixed-model analysis of variance with significance level set at P<0.05. ResultsA general increasing trend is present from 3 to 6weeks for most of the variables. The groups prepared to be press fit seemed to present higher values, which were maintained throughout the observation period. The reamer group presented the lowest BIC probably due to the drilling technique; however qualitatively, more new bone seemed to be in contact to the implant surface, at 3weeks, whereas the implants placed in press-fit situations were mainly supported by cortical bone. ConclusionThe laser-etched microgrooved implant presented osteoconductive and biocompatible properties for all surgical procedures tested. However, procedures providing increasingly higher press-fit scenarios presented the strongest histomorphometric and biomechanical responses at 3 and 6 weeks.
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| 6. |
- Tovar, Nick, et al.
(author)
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The physicochemical characterization and in vivo response of micro/nanoporous bioactive ceramic particulate bone graft materials
- 2014
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In: Materials science & engineering. C, biomimetic materials, sensors and systems. - : Elsevier. - 0928-4931 .- 1873-0191. ; 43, s. 472-480
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Journal article (peer-reviewed)abstract
- In this study, the physicochemical characteristics of calcium phosphate based bioactive ceramics of different compositions and blends presenting similar micro/nanoporosity and micrometer scale surface texture were characterized and evaluated in an in vivo model. Prior to the animal experiment, the porosity, surface area, particle size distribution, phase quantification, and dissolution of the materials tested were evaluated. The bone regenerative properties of the materials were evaluated using a rabbit calvaria model. After 2, 4, and 8 weeks, the animals were sacrificed and all samples were subjected to histologic observation and histomorphometric analysis. The material characterization showed that all materials tested presented variation in particle size, porosity and composition with different degrees of HA/TCP/lower stoichiometry phase ratios. Histologically, the calvarial defects presented temporal bone filling suggesting that all material groups were biocompatible and osteoconductive. Among the different materials tested, there were significant differences found in the amount of bone formation as a function of time. At 8 weeks, the micro/nanoporous material presenting similar to 55,TCP:45%,HA composition ratio presented higher amounts of new bone regeneration relative to other blends and a decrease in the amount of soft tissue infiltration. (C) 2014 Elsevier B.V. All rights reserved.
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| 7. |
- Yoo, Daniel, et al.
(author)
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Increased osseointegration effect of bone morphogenetic protein 2 on dental implants : An in vivo study
- 2014
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In: Journal of Biomedical Materials Research. Part A. - : Wiley-Blackwell. - 1549-3296 .- 1552-4965. ; 102:6, s. 1921-1927
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Journal article (peer-reviewed)abstract
- Application of recombinant human bone morphogenetic protein 2 (rhBMP-2) to implant surfaces has been of great interest due to its osteoinductive potential. However, the optimal coating methodology has not been clarified. The objective of the study was to determine whether the application of rhBMP-2 onto plasma-sprayed hydroxyapatite implant surfaces by immersion in protein solution before implant installation would result in significantly improved bone apposition. Using a sheep iliac model, titanium (Ti) and plasma-sprayed calcium-phosphate (PSCaP)-coated implants uncoated and coated with rhBMP-2 were assessed for their osteogenic effects in the peri-implant area over time in terms of osseointegration and de novo bone formation. After 3 and 6 weeks postoperatively, the samples were retrieved and were subjected to bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) evaluation. When rhBMP-2 was applied to the PSCaP surface, significant increases in BIC and BAFO were observed at 3 weeks in vivo, whereas when adsorbed directly onto the titanium implant surface, rhBMP-2 did not as effectively improve the bone response (although significantly higher than control Ti). The outcomes of the present study suggested that the combination of plasma-sprayed calcium-phosphate surface and rhBMP-2 coating significantly enhanced osseointegration, which validated the postulated hypothesis. (c) 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1921-1927, 2014.
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