Abstract Sodium alendronate is a bisphosphonate drug that exerts antiresorptive action and is used to treat osteoporosis. Objective The aim of this study was to evaluate the bone repair process at the bone/implant interface of osteoporotic rats treated with sodium alendronate through the analysis of microtomography, real time polymerase chain reactions and immunohistochemistry (RUNX2 protein, bone sialoprotein (BSP), alkaline phosphatase, osteopontin and osteocalcin). Material and Methods A total of 42 rats were used and divided in to the following experimental groups: CTL: control group (rats submitted to fictitious surgery and fed with a balanced diet), OST: osteoporosis group (rats submitted to a bilateral ovariectomy and fed with a low calcium diet) and ALE: alendronate group (rats submitted to a bilateral ovariectomy, fed with a low calcium diet and treated with sodium alendronate). A surface treated implant was installed in both tibial metaphyses of each rat. Euthanasia of the animals was conducted at 14 (immunhostochemistry) and 42 days (immunohistochemistry, micro CT and PCR). Data were subjected to statistical analysis with a 5% significance level. Results Bone volume (BV) and total pore volume were higher for ALE group (P<0.05). Molecular data for RUNX2 and BSP proteins were significantly expressed in the ALE group (P<0.05), in comparison with the other groups. ALP expression was higher in the CTL group (P<0.05). The immunostaining for RUNX2 and osteopontin was positive in the osteoblastic lineage cells of neoformed bone for the CTL and ALE groups in both periods (14 and 42 days). Alkaline phosphatase presented a lower staining area in the OST group compared to the CTL in both periods and the ALE at 42 days. Conclusion There was a decrease of osteocalcin precipitation at 42 days for the ALE and OST groups. Therefore, treatment with short-term sodium alendronate improved bone repair around the implants installed in the tibia of osteoporotic rats.

INTRODUÇÃO: o ensaio em modelos de gesso tem grande importância para o planejamento em cirurgia ortognática. OBJETIVO: neste artigo, será apresentado, passo-a-passo, uma técnica de cirurgia de modelos iniciando pela mandíbula, destacando aspectos importantes e as vantagens deste procedimento.

INTRODUCTION: The cast surgery has great importance in orthognatic surgery treatment planning. AIM: In this article, a step by step lower model surgery will be presented, emphasizing important details and advantages of this procedure.

A capacidade de um pool de proteínas morfogenéticas bovinas ligada a hidroxiapatita sintética absorvível microgranular (BMPb-HA) em estimular a reparação óssea foi avaliada em defeito de tamanho crítico em calvária de rato. Defeitos de 8 mm diâmetro foi produzido na calvária de 25 ratos, sendo 15 preenchidos com BMPb-HA homogeinizado com sangue (grupo experimental) e 10 somente com coágulo sanguíneo (grupo controle). As calvárias dos animais do grupo experimental foram coletadas 1, 3 e 6 meses após as cirurgias e as do grupo controle, ao término da cirurgia e após 6 meses. Os resultados morfométricos obtidos nas imagens radiográficas apresentou ausência de formação óssea nos períodos de 1 e 3 meses e, histologicamente os defeitos estavam preenchidos por tecido conjuntivo fibroso e inúmeros focos de reação granulomatosa, tipo corpo estranho, ao redor de aglomerados de hidroxiapatita. Ao final de 6 meses, os focos de reação granulomatosa diminuiu em número e tamanho e os defeitos diminuíram a sua área em 22% em relação ao controle 0 hora, devido a neoformação óssea nas suas bordas, mas apresentaram área semelhante ao controle 6 meses. Concluímos que a utilização de BMPb-HA no tratamento de defeitos ósseos cranianos em ratos, promove a formação de reação granulomatosa tipo corpo estranho que inibe profundamente a neoformação óssea, sugerindo que a hidroxiapatita sintética microgranular não é um bom carreador para as BMPs expressarem o seu potencial indutor.

The ability of a pool of bovine bone morphogenetic proteins bound to synthetic microgranular hydroxyapatite (BMPb-HA) to stimulate bone repair was determined in rat critical size defects. An 8-mm diameter defect was created in the calvaria of 25 rats. In 15 rats, the defects were filled with BMPb-HA homogenized with blood (experimental group), and in 10 rats the defects were filled only with blood clots (control). The calvariae of experimental rats were collected 1, 3 and 6 months after surgery and of the control rats at the end of surgery and 6 months thereafter. The morphometric results obtained in the radiographs showed an absence of new bone formation at 1 and 3 months post-surgery and, histologically, the defects were filled with fibrous connective tissue and numerous foci of a foreign body-type granulomatous reaction around hydroxyapatite agglomerates. At the end of 6 months, the number and size of the granulomatous foci decreased and the area of the defects was reduced by 22% compared to the 0-hour control due to the formation of new bone at their borders, although the mean area was similar to the 6-month control. We conclude that the use of BMPb-HA in the treatment of critical size bone defects of the rat skull leads to the formation of a foreign body-type granulomatous reaction that markedly inhibits new bone formation, suggesting that synthetic microgranular hydroxyapatite does not represent a good carrier for BMP-induced bone formation.