Bovine hydroxyapatite (Bio-Oss (R)) induces osteocalcin, RANK-L and osteoprotegerin expression in sinus lift of rabbits

Purpose: the aim of this study was to analyze and compare the expression of osteocalcin, RANK-L, osteoprotegerin, in sinus lift procedures using bovine hydroxyapatite (HA).Material and methods: Twenty four male rabbits underwent bilateral sinus lift procedures were distributed into two groups, according to the sinus filling material: Group 1) autogenous bone graft; and Group 2) bovine HA. All groups were sacrificed after 14 and 30 days, for microscopic and immunohistochemistry analysis.Results: At 14 days after surgery, discrete osteogenesis was observed in the highly vascularized granulation tissue surrounding HA particles, as well as woven bone deposition on the biomaterial surface. Following 30 days, well organized bone trabeculas were seen surrounding the HA granules presenting areas of osteogenic activity. Morphometric findings did not show remarkable differences between groups. Bovine HA induced similar osteocalcin, RANK-L, osteoprotegerin immunoexpressivity when compared to autogenous bone graft group for both periods evaluated in this setting.Conclusion: Taken together, these data are consistent with the notion that HA has a similar biological behavior to autogenous bone graft in sinus lift of rabbits. (C) 2012 European Association for Cranio-Maxillo-Facial Surgery.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo, UNIFESP, Dept Biociencias, BR-10060001 Santos, SP, BrazilUniv Sagrado Coracao, Sch Dent, Dept Hlth Sci, Discipline Oral & Maxillofacial Surg, Bauru, SP, BrazilUniversidade Federal de São Paulo, UNIFESP, Dept Biociencias, BR-10060001 Santos, SP, BrazilFAPESP: 2007/04767-3Web of Scienc

Effect of low-level laser therapy on intramembranous and endochondral autogenous bone grafts healing

The aim of this study was to evaluate the healing process of intramembranous (IM) and endochondral (EC) bone grafts under low-level laser therapy (LLLT). Male rabbits underwent onlay autogenous bone grafts (1 cm in diameter) retrieved from the calvaria and iliac crest and fixed on parietal bones, divided into four groups: Calvaria (C), Iliac (I), Calvaria + LLLT (C+L), and Iliac + LLLT (I+L). Animals from C+L and I+L Groups had their grafts exposed to LLLT (AlGaAs–808 nm, CW, 30 mW, 0.028 cm2 average laser beam area), 15 s irradiation time (16 J/cm2 per point–total of 64 J/cm2 per session). After 7, 14, 30, and 60 days, grafts were retrieved and resorption pattern analyzed by means of morphometry and TRAP-positive osteoclasts detection. Differences in the resorption levels of iliac grafts were observed, presenting 40% in I group against 8% in I+L grafts at the 14th day of evaluation (P \u3c 0.05). After 30 days, resorption was maintained at 41% in I group, whereas I+L presented 15% in the same period (P = 0.0591). No significant differences were noted in the rates of calvaria grafts resorption in all periods. A significant higher number of osteoclasts on the grafts\u27 surface was observed in C+L Group at day 30, in comparison with C group. In I+L Group, prevalence of osteoclasts was marked at day 7 (P \u3c 0.05) in comparison to I Group. In general, it was concluded that biomodulative effects of LLLT did not significantly affect healing and resorption processes of autogenous bone grafts from EC and IM origins

Cyclooxygenase-2 inhibition does not impair block bone grafts healing in rabbit model

Success of alveolar reconstructions using onlay autogenous block bone grafts depends on their adequate integration to the recipient bed influenced by a number of local molecules. Considering the fundamental role of cyclooxygenase (COX-2) in bone repair, the aim of this study was to analyze the effect of its inhibition in the integration of endochondral (EC) iliac crest, and intramembranous (IM) calvaria bone grafts. Thirty-two rabbits were divided into 4 groups: Calvaria Control (CC) and Iliac Control—treated with oral 0.9 % saline solution, and Calvarial-NSAID (C-NSAID) and Iliac-NSAID (I-NSAID) groups—treated with oral 6 mg/Kg non-steroidal anti-inflammatory drug etoricoxib. After 7, 14, 30 and 60 days the animals were euthanized and the specimens removed for histological, histomorphometric and immunohistochemistry analysis. At day 60, a tight integration of IM blocks could be seen with the presence of remodeling bone, whereas integration of EC grafts was mainly observed at the edges of the grafts. A significant higher percentage of bone matrix in the interface region of the CC grafts in comparison to C-NSAID only at day 14, whereas no differences were detected comparing the EC grafts. No differences were observed in Runx-2 and vascular endothelial growth factor (VEGF) immunolabeling when comparing CC and C-NSAID groups, while a significant weaker Runx-2 and VEGF labeling was detected in I-NSAID group at day 60. Although some influence was detected in osteogenesis, it is concluded that drug induced inhibition of COX-2 does not impair onlay bone grafts’ healing of both embryologic origins in rabbits

Bioactive glass-ceramic bone repair associated or not with autogenous bone: a study of organic bone matrix organization in a rabbit critical-sized calvarial model

Objective The aim of the study was to analyze bone matrix (BMX) organization after bone grafting and repair using a new bioactive glass-ceramic (Biosilicate®) associated or not with particulate autogenous bone graft. Material and methods Thirty rabbits underwent surgical bilateral parietal defects and divided into groups according to the materials used: (C) control—blood clot, (BG) particulate autogenous bone, (BS) bioactive glass-ceramic, and BG + BS. After 7, 14, and 30 days post-surgery, a fragment of each specimen was fixed in − 80 °C liquid nitrogen for zymographic evaluation, while the remaining was fixed in 10% formalin for histological birefringence analysis. Results The results of this study demonstrated that matrix organization in experimental groups was significantly improved compared to C considering collagenous organization. Zymographic analysis revealed pro-MMP-2, pro-MMP-9, and active (a)-MMP-2 in all groups, showing gradual decrease of total gelatinolytic activity during the periods. At day 7, BG presented more prominent gelatinolytic activity for pro-MMP-2 and 9 and a-MMP-2, when compared to the other groups. In addition, at day 7, a 53% activation ratio (active form/[active form + latent form]) was evident in C group, 33% in BS group, and 31% in BG group. Conclusion In general, BS allowed the production of a BMX similar to BG, with organized collagen deposition and MMP-2 and MMP-9 disponibility, permitting satisfactory bone remodeling at the late period. Clinical relevance The evaluation of new bone substitute, with favorable biological properties, opens the possibility for its use as a viable and efficient alternative to autologous bone graft

A novel bioactive vitroceramic presents similar biological responses as autogenous bone grafts

Bioactive glasses represent an interesting class of bone substitute's biomaterials. the present study investigated the repair of bone defects filled with a novel bioactive vitroceramic (Biosilicate(A (R))), alone or in association with particulate autogenous bone grafts in calvaria defects of rabbits. After 7, 14, and 30 days the specimens were retrieved for histological, histomorphometric and immunohistochemistry analysis. Satisfactory bone formation was observed in all groups, and direct bone-biomaterial surface was noted. Histomorphometric assessment did not show statistically significant differences in bone formation among the groups and periods, except for BG group at day 14. Immunoexpression of Runx-2 was similar among the groups containing the graft and the biomaterial, being more intense than in control group. Similar result was observed for VEGF expression, especially in the last experimental period. These results revealed that Biosilicate(A (R)) presented a favorable behavior, comparable to autogenous bone graft.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Univ Sagrado Coracao, Dept Hlth Sci, Discipline Oral & Maxillofacial Surg, BR-17013070 Bauru, SP, BrazilUniv Sagrado Coracao, Sch Dent, BR-17011160 Bauru, SP, BrazilUniv Sagrado Coracao, Dept Hlth Sci, Discipline Oral & Maxillofacial Surg, BR-17011160 Bauru, SP, BrazilUniv Sagrado Coracao, Dept Hlth Sci, Discipline Periodontol, BR-17011160 Bauru, SP, BrazilUniversidade Federal de São Paulo, Dept Biosci, BR-11060001 Santos, SP, BrazilUniversidade Federal de São Paulo, Dept Biosci, BR-11060001 Santos, SP, BrazilFAPESP: 2008/11485-8FAPESP: 2009/17294-1Web of Scienc

Estudo comparativo do desempenho de diferentes membranas oclusivas de Látex Natural no reparo ósseo

Introduction: In dentistry, alveolar bone resorption is a limiting factor in the well being of individuals directly interfering in the stomatognathic system, causing problems in the context of overall health. Aiming to promote biological methods that can stimulate bone regeneration, several biomimetic strategies have been developed by the use of diverse materials possible to the bone matrix, culminating in the development of techniques that promote such repair. Objective: This work is a comparative study of the performance of films made with latex as occlusive membrane for Guided Bone Regeneration (GBR) procedure in three preparations: Latex preserved in ammonia, produced by Latex rubber clones IAN873 and PR255 polymerized immediately after collection and without use ammonia as a preservative. Methods: Sixty Wistar rats were randomly divided into 4 groups of 15 animals in which bone defects of critical size (8mm diameter) were made surgically in the skull. Group A was treated by GBR through the membrane latex preserved with ammonia, Group B received the membrane made of latex from IAN873, Group C, the membrane clone PR255 and group D was not treated by GBR. After a period of 7, 15 and 50 days, 5 animals from each group were euthanized, and specimens containing bone defect collected for microscopic examination (descriptive histology and histomorphometry). Results: The results showed that after 50 days there was bone formation in higher proportions in group D (p <0.05, ANOVA followed by Tukey), suggesting that further experiments should be conducted to conclude about the presence of ammonia and the influence of kind of rubber. Conclusion: GOR is a procedure proven effective in the treatment of bone defects. Therefore, further experiments should be conducted to reach a conclusion regarding the presence of ammonia in the latex composition for the manufacture of membranes, as well as the difference induced by the species of rubber.Introdução: Na odontologia, a reabsorção óssea alveolar é fator limitante no bem estar dos indivíduos interferindo diretamente no sistema estomatognático, acarretando problemas no âmbito de saú- de em geral. Com o objetivo de promover modalidades biológicas que possam estimular a regeneração óssea, várias estratégias biomiméticas têm sido desenvolvidas recorrendo à utilização dos mais diversos materiais possíveis à matriz óssea, culminando com o desenvolvimento de técnicas que promovam tal reparo. Objetivo: Este trabalho consiste no estudo comparativo do desempenho de filmes confeccionados com Látex como membrana oclusiva em procedimento de Regeneração Óssea Guiada (ROG) em 3 preparações: Lá- tex preservado em amônia, Látex produzidos por seringueiras dos clones IAN873 e PR255 polimerizados logo após a coleta e sem uso de amônia como conservante. Métodos: Foram utilizados 60 ratos Wistar, divididos randomicamente em 4 grupos de 15 animais, nos quais defeitos ósseos de tamanho crítico (8mm de diâmetro) foram confeccionados cirurgicamente na calvária. O Grupo A foi tratado por ROG através da membrana de Látex preservada em amônia, o Grupo B recebeu a membrana do clone IAN873, o Grupo C, a membrana do clone PR255 e o grupo D, não foi tratado por ROG. Após o período de 7, 15 e 50 dias, 5 animais de cada grupo foram eutanasiados, e as peças contendo o defeito ósseo coletadas para análise microscópica (histológica descritiva e histomorfometria). Resultados: Os resultados demonstraram que após 50 dias, houve formação óssea em maiores proporções no grupo D (p<0.05, ANOVA seguido de Tukey), sugerindo que novos experimentos devem ser realizados para se concluir a respeito da presença da amônia e a influência da espécie de seringueira. Conclusão: A ROG é um procedimento comprovadamente eficaz no tratamento de defeitos ósseos. Sendo assim, novos experimentos devem ser realizados para se concluir a respeito da presença da amônia na composição do látex para fabricação de membranas, bem como na diferença induzida pela espécie de seringueira

Polyurethane derived from Ricinus Communis as graft for bone defect treatments

<div><p>Abstract This work evaluated polyurethane (Polyquil®) as a graft for treatment of bone defects. Bone defects of 1.5 × 0.5 cm were made in the calvaria of 16 rabbits. Eight animals had their defects treated with Polyurethane (Treated) and 8 of them had their defects filled with blood clot (Control). In the second experiment, segmental defects of 0.5 cm were performed at the zygomatic arch of 16 rabbits. Eight animals were treated by guided bone regeneration, using a latex membrane, associated to grafting of polyurethane while the others were not treated (Control). The bone tissue morphometry in the craniotomy experiment resulted in a higher bone volume in the Treated group at 60 days (p <0.05, t student test). Microscopic and radiographic images demonstrate the formation of a bone bridge in the segmental defect, 60 and 120 days after surgery in the Treated group, different from the Control group with incomplete healing.</p></div