ABSTRACT Purpose: to evaluate biocompatibility and osteogenic potential of hydroxyapatite/alginate composite after its implantation on rat calvarian critical bone defect. Methods: thirty adults male Wistar rats were randomly distributed into two groups: GHA – critical bone defect filled with hydroxyapatite/alginate composite granules (HA/Alg) and CG – critical bone defect without biomaterial; evaluated at biological points of 15, 45 and 120 days. Results: the histomorphometrically analyses for GHA showed osteoid matrix deposition (OM) among the granules and towards the center of the defect in centripetal direction throughout the study, with evident new bone formation at 120 days, resulting in filling 4/5 of the initial bone defect. For CG, this finding was restricted to the edges of the bone margins and formation of connective tissue on the residual area was found in all biological points. Inflammatory response on GHA was chronic granulomatous type, discrete and regressive for all biological points. Throughout the study, the CG presented mononuclear inflammatory infiltrate diffuse and regressive. Histomorphometry analyses showed that OM percentage was evident for GHA group when compared to CG group in all analyzed periods (p > 0.05). Conclusions: the biomaterial evaluated at this study showed to be biocompatible, bioactive, osteoconductive and biodegradable synchronously with bone formation. Purpose hydroxyapatitealginate hydroxyapatite alginate Methods groups HA/Alg HAAlg HA Alg (HA/Alg 15 4 12 days Results (OM 5 4/ type p 0.05. 005 0.05 . 0 05 0.05) Conclusions biocompatible bioactive 1 00 0.0 0.

Abstract The objective was to evaluate the effect of oral administration of strontium (Sr) on the regeneration of a critical bone defect. Twenty Wistar rats were divided into two groups, assessed at 15 and 60 days postoperatively: GSr - oral administration of Sr; and CG - without oral administration of Sr. At 15 and 60 days, blood was collected to measure Sr and calcium (Ca), and the calvaria was removed for histomorphological and histomorphometric analyses. Sr+2 plasmatic concentrations were higher in GSr than in CG. The dosage of Ca+2 showed a small increase in the CG about the GSr. In all evaluated groups, new bone formation was restricted to the edges of the defect, and the residual area was filled with fibrous connective tissue. The oral administration of Sr associated with HA microspheres substituted by the metal, in a concentration of 23 mol%, did not affect the formation of the osteoid matrix. (Sr defect groups 1 6 postoperatively Ca, Ca , (Ca) analyses Sr2 2 Sr+ Ca2 Ca+ tissue metal mol mol% matrix (Ca

Resumo Objetivo Comparar o efeito de dois protocolos de ultrassom terapêutico com diferentes tempos de exposição para regeneração de defeito ósseo crítico. Métodos Foram utilizados 45 ratos, machos, distribuídos em três grupos: grupo ultrassom terapêutico 5 minutos (GUS 5); grupo ultrassom terapêutico 10 minutos (GUS 10); e grupo controle (GC). Em todos os grupos, confeccionou-se um defeito ósseo crítico, com 8,5 mm de diâmetro, na região da calvária. O protocolo foi iniciado no 1º dia do pós-operatório, no GUS 5 e no GUS 10, com ultrassom terapêutico na frequência de 1,0 MHz, modo pulsado, 5 vezes por semana, nos períodos de 15, 30, e 60 dias. Resultados Dentre os grupos experimentais, houve maior neoformação de matriz osteoide no GUS 10, seguido do GUS 5 quando comparados ao GC, no qual a neoformação foi restrita à região de borda. O uso do ultrassom promoveu aumento na espessura da matriz conjuntiva, proliferação de capilares, alinhamento das fibras colágenas, redução do edema e do processo inflamatório, tendo sido mais significativo no tempo de 10 minutos. Conclusão O ultrassom terapêutico estimulou o reparo do defeito ósseo crítico, e o maior tempo de exposição promoveu maior estímulo osteogênico.

Abstract Objective To compare the effect of two therapeutic ultrasound protocols, with different times of exposure in the regeneration of critical bone defect. Methods Forty-five male rats were distributed among three experimental groups: therapeutic ultrasound group 5 minutes (TUG 5); therapeutic ultrasound group 10 minutes (TUG 10); and control group (CG). In all groups, a critical bone defect of 8.5 mm diameter was made in the calvaria region. The protocol was initiated on the 1st postoperative day in TUGs 5 and 10, with therapeutic ultrasound at the frequency of 1.0 MHz, pulsed mode, five times a week, at periods of 15, 30, and 60 days. Results Among the experimental groups, the highest volume of neoformation of osteoid matrix took place in the TUG 10 group followed by TUG 5, when compared with the CG group, in which the neoformation was restricted to the border region. The use of ultrasound promoted an increase in the thickness of the conjunctive matrix, proliferation of capillaries, alignment of the collagen fibers, reduction of edema and inflammatory process, being more significant in the 10-minutes time period. Conclusion Therapeutic ultrasound stimulated the repair of a critical bone defect, and the longer exposure time promoted greater osteogenic stimulation.