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BackgroundIn this study, the biocompatibility, stability and osteotransductivity of a new cement based on alpha-tricalcium phosphate (alpha-TCP) were investigated in a bone repair model using a rat model.MethodsThe potential of alpha-TCP on bone repair was compared to autogenous bone grafting, and unfilled cavities were used as negative control. Surgical cavities were prepared and designated as test (T), implanted with alpha-TCP blocks; negative control (C - ), unfilled; and positive control (C + ), implanted with autogenous bone graft. Results were analyzed on postoperative days three, seven, 14, 21 and 60.ResultsThe histological analyses showed the following results. Postoperative day three: presence of inflammatory infiltrate, erythrocytes and proliferating fibroblasts in T, C - and C + samples. Day seven: extensive bone neoformation in groups T and C + , and beginning of alpha-TCP resorption by phagocytic cells. Days 14 and 21: osteoblastic activity in the three types of cavities. Day 60: In all samples, neoformed bone similar to surrounding bone. Moderate interruption on the ostectomized cortical bone.ConclusionsBone neoformation is seen seven days after implantation of alpha-TCP and autogenous bone. Comparison of C - with T and C + samples showed that repair is faster in implanted cavities; on day 60, control groups presented almost complete bone repair. Alpha-TCP cement presents biocompatibility and osteotransductivity, besides stability, but 60 days after surgery the cavities were not closed.

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Objectives This study aimed to evaluate the potential of adipose-derived stem cells (ASCs) combined with a modified α-tricalcium phosphate (α-TCP) or gelatin sponge (GS) scaffolds for bone healing in a rat model.Material and Methods Bone defects were surgically created in the femur of adult SHR rats and filled with the scaffolds, empty or combined with ASCs. The results were analyzed by histology and histomorphometry on days seven, 14, 30, and 60.Results Significantly increased bone repair was observed on days seven and 60 in animals treated with α-TCP/ASCs, and on day 14 in the group treated with GS/ASCs, when compared with the groups treated with the biomaterials alone. Intense fibroplasia was observed in the group treated with GS alone, on days 14 and 30.Conclusions Our results showed that the use of ASCs combined with α-TCP or GS scaffolds resulted in increased bone repair. The higher efficacy of the α-TCP scaffold suggests osteoconductive property that results in a biological support to the cells, whereas the GS scaffold functions just as a carrier. These results confirm the potential of ASCs in accelerating bone repair in in vivo experimental rat models. These results suggest a new alternative for treating bone defects.

IntroduçãoEm toda atividade odontológica, tão importante quanto o aprimoramento técnico e científico é a conscientização dos riscos de contaminação e infecção durante o atendimento. Com a finalidade de reduzir o número de microrganismos presentes em instrumento ou superfície, um dos procedimentos comumente utilizados na odontologia é a desinfecção. Segundo Block 1 (2001) a desinfecção é a destruição de patógenos e outros tipos de microrganismos por mecanismos térmicos e químicos, mas não em todas as formas, como os esporos bacterianos.Diversos agentes podem ser utilizados para a desinfecção de instrumentos. Dentre os existentes, os que serão analisados no estudo são: solução aquosa de digluconato de clorexidina 0,12%, solução alcoólica de digluconato de clorexidina 0,12%, solução aquosa de digluconato de clorexidina 2%, solução alcoólica de digluconato de clorexidina 2%, álcool 70% e compostos de iodo. Almejando o sucesso da desinfecção, deve-se conhecer do agente o mecanismo de ação sobre os microrganismos, toxicidade para o manipulador e ação deletéria para o equipamento a ser desinfetado 2 . As soluções de digluconato de clorexidina, tanto alcoólica quanto aquosa, são anti-sépticos químicos, com ação antifúngica, bactericida e bacteriostática. O mecanismo de ação decorre da diminuição da tensão superficial e da estrutura proteica, através de desnaturação das membranas celulares 3 .

ObjectivesThe present study aimed at performing a histological evaluation of the response of temporal bone tissue to a change of direction of the force vector of the mandible in relation to the base of the skull. Material and methodsAdult rabbits were assigned into four groups with two control and four experimental animals in each group. Experimental animals underwent surgery, which resulted in a change of direction of the force vector on the right temporomandibular joint. Samples were collected after 15, 30, 60 and 90 days for histological analysis. ResultsIn the two-way analysis of variance, the effect of group and time was statistically significant (p<0.001). Additionally, a statistically significant interaction between group and time was observed (p<0.001). Control animals showed normal growth and development of the temporal region. In the experimental group, the change in direction of the force vector of the mandible induced significant changes in the temporal bone, with a bone modeling process, which suggests growth of this cranial structure. ConclusionsThe methodology used in this experiment allows us to conclude that the change in direction of the force vector of the mandible in relation to the skull base induces remodeling and modeling processes in the temporal bone. The resumption of normal oral functions after bone healing of the mandibular fracture appears to increase cell activation in the remodeling and modeling of the temporal bone structure. The observation of areas of temporal bone modeling shows the relevance of further investigation on the correlation between the joint structures and craniofacial growth and development.

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