Morphometric evaluation of bone regeneration in segmental mandibular bone defects filled with bovine bone xenografts in a split-mouth rabbit model.

BACKGROUND: Bovine bone grafts have been widely used in dentistry for guided tissue regeneration and can support new bone formation in direct contact with the graft. The aim of this study was to compare the morphometric and bone density changes after using two different bovine bone graft blocks in segmental osseous defects in the mandible of rabbits following different postoperative periods. MATERIAL AND METHODS: Critical size segmental defects were surgically created bilaterally in the jaw of 18 rabbits. The defects were filled with either deproteinized bovine bone mineral with 10% collagen (DBBM-C; BioOss Collagen®), lyophilized bovine medullary bone (LBMB; Orthogen®), or left untreated according to a split-mouth design. Animals were sacrificed after 3 or 6 months of healing. The hemimandibles were scanned ex vivo using a high-resolution (19 µm) microcomputed tomography. Morphometric and bone density parameters were calculated in the region of the defect using CT-Analyser (Bruker). Initial graft blocks were used as baseline. RESULTS: DBBM-C presented a denser microarchitecture, in comparison to LBMB at baseline. DBBM-C and LBMB grafted regions showed a similar progressive remodeling, with a significant decrease in structure complexity and maintenance of bone volume fraction during the postoperative follow-up periods. Both graft materials showed an enhanced bone replacement and more complex structure compared to untreated defects. The apparent fusion between the graft and host bone was observed only in the defects filled with LBMB. CONCLUSION: LBMB grafts showed a similar behavior as DBBM-C regarding structural remodeling. In LBMB samples, apparent integration between the host bone and the graft was present.

Orthognathic surgery in patients with cleidocranial dysplasia.

The aim of this study was to report the orthodontic-surgical approach of a 21-year-old female patient diagnosed with cleidocranial dysplasia. An orthognathic surgery was performed in the maxilla and mandible during the same procedure to correct an existing dentofacial deformity (class III malocclusion). In addition, malar prostheses were used to correct midface deficiency. After surgical intervention, orthodontic treatment continued in order to promote stability, function, and aesthetics. Cases of cleidocranial dysplasia treated with the defined criteria can bring aesthetic and functional benefits to the patient.

Análise tomográfica da formação óssea em defeito segmentar na mandíbula de coelhos preenchido com osso bovino liofilizado em bloco com colágeno / Tomographic analysis of bone formation in segmental defect in the mandible of rabbits filled with lyophilized bovine bone block with collagen

Atualmente a implantodontia tem evoluído muito na intenção de substituir perdas dentárias, porém infelizmente nem sempre isto é capaz, uma vez que após a perda dentária, na grande maioria das vezes, o osso remanescente também é reabsorvido, dificultando ou impossibilitando a instalação de implantes osseointegrados. Esse tipo de perda óssea nos maxilares ou as perdas ósseas resultantes de ressecções cirúrgicas, constituem uma preocupação importante na atualidade, uma vez que os cirurgiões dentistas pesquisam um substituto ósseo que devolva a forma e o contorno dos ossos da face e dos maxilares, e/ou que permita a instalação de implantes osseointegrados. Dentre os biomateriais, a utilização do osso bovino liofilizado tem se popularizado e vem ganhando mercado uma vez que reduz a morbidade do paciente evitando a retirada de enxertos autógenos e tem apresentado uma boa previsibilidade de resultados. No presente estudo, foram criados defeitos ósseos na base da mandíbula de coelhos, onde foram enxertados blocos de osso bovino liofilizado com colágeno suíno nos grupos experimentais e deixados vazios nos grupos controle. Os animais foram sacrificados nos tempos 0 (imediatamente após a cirurgia), 3 e 6 meses após o procedimento cirúrgico. As mandíbulas foram coletadas e analisadas através de tomografias computadorizadas de feixe cônico, em que se analisou a capacidade do enxerto de auxiliar no reparo ósseo de defeitos de tamanho crítico criados na mandíbula de coelhos, bem como sua capacidade de manter o contorno e forma do osso. Através da análise tomográfica das áreas enxertadas foi possível concluir que de acordo com a metodologia proposta o enxerto de osso bovino com 10% de colágeno suíno não foi capaz de auxiliar em 100% no reparo ósseo dos defeitos de tamanho crítico criados na mandíbula dos coelhos, mostrando uma camada fina de tecido mole entre o enxerto e o leito Tendo sido eficiente no preenchimento do espaço do defeito e manutenção do contorno ósseo.

Currently implant dentistry has evolved tremendously in the intention of replacing missing teeth, but unfortunately this is not always able, since after tooth loss, in most cases, also the remaining bone is reabsorbed, making it difficult or impossible to install dental implants. This type of bone loss in the jaw or bone loss resulting from surgical resections, are a major concern at present, since the dentists researching bone substitute that restores the shape and contour of the bones of the face and jaws, and/or enabling installation of dental implants. Among the biomaterials, the use of lyophilized bovine bone has become popular and has been gaining ground as it reduces the morbidity of the patient avoiding the removal of autogenous grafts has shown a good and predictable results. In the present study, bone defects were created on the basis of mandible in rabbits, which were grafted blocks lyophilized bovine bone with swines collagen in the experimental groups and control groups left empty. The animals were sacrificed at 0 (immediately after surgery), 3 and 6 months after surgery. The jaws were collected and analyzed using cone beam computed tomography, which analyzed the ability of the graft to aid in bone repair of critical-size defects created in the mandible of rabbits as well as its ability to maintain the contour and shape of the bone. Through the analysis of the tomographic grafted areas was concluded that according to the methodology proposed bovine bone graft with 10% swines collagen was not able to assist in 100% of the bone repair critical size defects created in rabbit jaw, showing a thin layer of soft tissue between the graft and the bed having been efficient space filling of the defect and maintain the bone contour.