Healing of buccal dehiscence defects at implants installed immediately into extraction sockets - an experimental study in dogs

Aim: To evaluate the influence of implant positioning into extraction sockets on bone formation at buccal alveolar dehiscence defects. Material and Methods: In six Labrador dogs the pulp tissue of the mesial roots of 4P4 was removed and the root canals were filled. Flaps were elevated bilaterally, the premolars hemi-sectioned and the distal roots removed. The implants were placed in contact with either the buccal (test site) or with the lingual (control site) bony wall of the extraction sockets. Healing abutments were affixed and triangular buccal bony dehiscence defects, about 2.7 mm deep and 3.5 mm wide, were then prepared. No regenerative procedures were done and a non-submerged healing was allowed. After 4 months of healing, block sections of the implant sites were obtained for histological processing and peri-implant tissue assessment. Results: After 4 months of healing, the bony crest and the coronal border of osseointegration at the test sites were located 1.71 ± 1.20 and 2.50 ± 1.21 mm apically to the implant shoulder, respectively. At the control sites, the corresponding values were 0.68 ± 0.63 and 1.69 ± 0.99 mm, respectively. The differences between test and control reached statistical significance (P < 0.05). Residual marginal bone defects were found both at the test and control sites. A statistically significant difference between test and control sites was only found at the lingual aspects (depth 2.09 ± 1.01 and 1.01 ± 0.48 mm, respectively). Similar heights of the buccal biological width were observed at both sites (about 5.1 mm). Conclusions: The placement of implants in a lingual position of the extraction sockets allowed a higher degree of bone formation at buccal alveolar dehiscence defects compared with a buccal positioning. © 2012 John Wiley & Sons A/S.

The relationship between visceral fat thickness and bone mineral density in sedentary obese children and adolescents

Background: Among adults, obesity has been positively related to bone mineral density. However, recent findings have pointed out that abdominal obesity could be negatively related to bone density. The above mentioned relationship is not clear among pediatric populations. Therefore, this cross-sectional study analyzed the relationship between thickness of abdominal adipose tissue and bone mineral variables in sedentary obese children and adolescents.Methods: One hundred and seventy five obese children and adolescents (83 male and 92 female) with ages ranging from 6 to 16 years-old were analyzed. Bone mineral content and density were estimated by dual-energy X-ray absorptiometry and ultrasound equipment which estimated the thickness of the abdominal adipose tissue. Pubertal stage was self-reported by the participants.Results: The mean age was 11.1 (SD = 2.6). Thickness of the abdominal adipose tissue was negatively related to bone mineral density (r = -0.17 [r95%CI: -0.03;-0.32]), independent of gender, pubertal stage and other confounders (β = -0.134 ± 0.042 [β95%CI: -0.217; -0.050]).Conclusions: In sedentary obese children and adolescents abdominal obesity is negatively related to bone mineral density, suggesting a potential link between abdominal obesity and osteoporosis. © 2013 Júnior et al.; licensee BioMed Central Ltd.

Increased osseointegration effect of bone morphogenetic protein 2 on dental implants: An in vivo study

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. © 2013 Wiley Periodicals, Inc.

Evaluation of the presence of VEGF, BMP2 and CBFA1 proteins in autogenous bone graft: Histometric and immunohistochemical analysis

Aims: The purpose of this study was to evaluate the expression of proteins that participate in the osteoinduction stage (VEGF, BMP2 and CBFA1) of the process of bone regeneration of defects created in rat calvariae and filled with autogenous bone block grafts. Materials and methods: 10 adult male rats (Rattus norvegicus albinus, Wistar) were used, who received two bone defects measuring 5 mm each in the calvariae. The bone defects constituted two experimental groups (n = 10): Control Group (CONT) (defects filled with a coagulum); Graft Group (GR) (defects filled with autogenous bone removed from the contralateral defect). The animals were submitted to euthanasia at 7 and 30 days post-operatively. Results: Quantitative analysis demonstrated significantly greater bone formation in Group GR, but the presence of the studied proteins was significantly greater in the CONT Group in both time intervals of observation. Conclusion: It was not possible in this study in cortical bone block groups to detect the osteoinductive proteins in a significant amount during the repair process. © 2013 European Association for Cranio-Maxillo-Facial Surgery.

The role of cytokines in inflammatory bone loss

Chronic inflammatory processes close to bone often lead to loss of bone in diseases such as rheumatoid arthritis, periodontitis, loosened joint prosthesis and tooth implants. This is mainly due to local formation of bone resorbing osteoclasts which degrade bone without any subsequent coupling to new bone formation. Crucial for osteoclastogenesis is stimulation of mononuclear osteoclast progenitors by macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor-κB ligand (RANKL) which induces their differentiation along the osteoclastic lineage and the fusion to mature, multinucleated osteoclasts. M-CSF and RANKL are produced by osteoblasts/ osteocytes and by synovial and periodontal fibroblasts and the expression is regulated by pro- and anti-inflammatory cytokines. These cytokines also regulate osteoclastic differentiation by direct effects on the progenitor cells. In the present overview, we introduce the basic concepts of osteoclast progenitor cell differentiation and summarize the current knowledge on cytokines stimulating and inhibiting osteoclastogenesis by direct and indirect mechanisms. © Informa Healthcare USA, Inc.

Estudo comparativo de reparação óssea em ratas ovariectomizadas tratadas com risedronato e Calcarea fluorica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização química e morfológica de implantes Ti-Mo com superfícies usinadas e modificadas por feixe de laser: análises biomecânica, histológica e histométrica em coelhos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação do copolímero de ácido polilático e poliglicólico associado ao vidro bioativo no processo de regeneração óssea: análise histomorfométrica e imunoistoquímica em ratos

Pós-graduação em Odontologia - FOA

Avaliação do cimento de fosfato-carbonato de cálcio no reparo ósseo de defeitos não-críticos em tíbia de rato: análise histológica, histométrica e imunoistoquímica

Pós-graduação em Odontologia - FOA

Avaliação dos enxertos ósseos autógenos triturados manualmente ou coletados durante osteotomia: análise histológica e histométrica em coelhos

Pós-graduação em Odontologia - FOA

Comparacão entre polímeros de mamona(Ricinus communis)e auto-enxerto ósseo esponjoso no tratamento de defeito ósseo segmentar induzido no rádio de coelhos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação histológica e histomorfométrica do reparo ósseo em tíbias osteotomizadas de ratos (Rattus novergicus albinus) frente à ausência de carga e tratamento com ultrassom

Pós-graduação em Ciência Animal - FMVA

Avaliação da reparação de feridas cutâneas e ósseas realizadas por técnicas convencionais e com laser de Er, Cr:YSGG: estudo em ratos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Tratamento de doença periodontal induzida em ratos através da aplicação de laser de Er, Cr:YSGG: análise histológica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influência do laser em baixa intensidade no processo de reparo de de enxerto ósseo autógeno implantado em bloco na mandíbula de ratos modificados sistemicamente com nicotina: estudo histo- morfométrico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)