Influence of the geometry of nanostructured hydroxyapatite and alginate composites in the initial phase of bone repair

Abstract Purpose: To analyze, histomorphologically, the influence of the geometry of nanostructured hydroxyapatite and alginate (HAn/Alg) composites in the initial phase of the bone repair. Methods: Fifteen rats were distributed to three groups: MiHA - bone defect filled with HAn/Alg microspheres; GrHA - bone defect filled with HAn/Alg granules; and DV - empty bone defect; evaluated after 15 days postoperatively. The experimental surgical model was the critical bone defect, ≅8.5 mm, in rat calvaria. After euthanasia the specimens were embedded in paraffin and stained with hematoxylin and eosin, picrosirius and Masson-Goldner's trichrome. Results: The histomorphologic analysis showed, in the MiHA, deposition of osteoid matrix within some microspheres and circumjacent to the others, near the bone edges. In GrHA, the deposition of this matrix was scarce inside and adjacent to the granules. In these two groups, chronic granulomatous inflammation was noted, more evident in GrHA. In the DV, it was observed bone neoformation restricted to the bone edges and formation of connective tissue with reduced thickness in relation to the bone edges, throughout the defect. Conclusion: The geometry of the biomaterials was determinant in the tissue response, since the microspheres showed more favorable to the bone regeneration in relation to the granules.

Eficacia de la hidroxiapatita en la cicatrización de injertos oseos e implantes dentales: una revisión sistemática de la literatura / Hydroxyapatite effectiveness in the healing of bone and implants dental implants: a systematic review of the literature

La hidroxiapatita (HA) es un componente mineral del hueso. Se ha comercializado la HA sintética o aloplástica en forma porosa o no porosa, densa y reabsorbible o no reabsorbible. Se utiliza como injerto óseo dada sus propiedades osteoconductivas y estimuladoras de proliferación celular generando así condiciones favorables para la regeneración tisular. El objetivo de éste trabajo es evaluar la efectividad del tratamiento con HA en cirugías de implantes dentales e injertos óseos. Se realizó una revisión sistemática. Se revisó ensayos clínicos sobre cicatrización y los injertos de HA sintética en Pubmed, Cochrane Library, Google Académico, Blackwell y Ebsco. Los criterios de selección son pacientes candidatos a tratamientos de defectos periodontales o rehabilitación con implantes dentales, sin alteraciones sistémicas de importancia. La estrategia se resume en los siguientes puntos: Identificación del problema, Identificación de términos de búsqueda, Búsqueda sistemática, Selección de artículos mediante utilización de guías de análisis crítico, Incorporación de la información al REVMAN®, Análisis de sesgos y Meta análisis. Al evaluar el metaanálisis se observa que la HA es efectiva para la cicatrización de injerto óseo. Cuando se omiten los estudios de bajo peso, la medida de resumen se mantiene en la HA. El tratamiento con HA en la cicatrización ósea y de implantes dentales resulta positivo y con una alta tasa de éxito en el largo plazo aunque su rango de efectividad varía con los materiales a los cuales ésta se asocie.

Hydroxyapatite (HA) is a mineral component of bone. Hydroxyapatite has been marketed as synthetic or alloplastic, porous or nonporous, dense and resorbable or non-resorbable form. It is used as bone graft due to its osteoconductive properties and stimulation of cell proliferation, generating favorable conditions for tissue regeneration. The aim of this study is to evaluate the effectiveness of treatment with HA in dental implant surgeries and bone grafts. We conducted a systematic review. Clinical trials on healing and graft of synthetic hydroxyapatite were reviewed in PubMed, Cochrane Library, Google Scholar, Blackwell and Ebsco. The selection criteria was: patient candidates for treatment of periodontal defects or rehabilitation with dental implants without significant systemic abnormalities. The strategy is summarized in the following: Identification of the problem, identifying search terms, systematic search and selection of articles by using critical analysis guides, Incorporating REVMAN ® information, unbiased analysis, and Meta-analysis. Assessing the meta-analysis shows that the HA is effective for healing bone graft. When omitting low weight studies, the summary measure remains in the HA. Treatment with HA in bone healing and dental implants, is positive with a high rate of success in the long term, although its effective range varies according to the materials to which it is associated.

Molars extraction for bone graft study in rabbits / Extração de molares para estudos de enxertos ósseos em coelhos

PURPOSE: The aim of this study was to describe an experimental surgical technique to be used in the evaluation of bone grafts in rabbits. METHODS: The operative technique was performed in jaws, with external approach from the labial commissure to the last molar tooth. An incision about 1cm extended forward to the alveolar ridge, followed by a exposing the cervical region of the alveolar bone and dental elements was done. Thus, after extraction of first molar with forceps, the tooth socket left was filled with hydroxyapatite. The bone gain was analyzed by histopathological studies. RESULTS: The histological analyses indicated formed bone surrounding the biomaterial. CONCLUSION: The experimental model using the tooth socket of the rabbit molar is a feasible procedure for studies of bone grafts.

OBJETIVO: Descrever uma técnica cirúrgica em coelhos para avaliação de enxertos ósseos. MÉTODOS: A técnica operatória consiste numa incisão na topografia da comissura labial até o ultimo molar. Uma incisão de 1cm no rebordo para expor o osso alveolar e a região cervical dos molares. Realizou-se a exodontia com fórceps e o alvéolo é preenchido com hidroxiapatita. Após o tempo de cicatrização é realizada a avaliação histológica. RESULTADOS: A análise histológica mostrou o novo osso formado rodeando biomaterial. CONCLUSÃO: O modelo cirúrgico para avaliação de enxertos ósseos utilizando molares de coelhos se mostrou factível.

Outcome of porous implants: incidence of complications, management, and morbidity.

OBJECTIVE: To determine the incidence of complications and the outcome associated with the use of three kinds of ocular porous implants. MATERIAL AND METHOD: Retrospective review of 133 consecutive case series. All patients undergoing orbital implantation either primary or secondary implantation of 49 coral hydroxyapatite, 43 human bone hydroxyapatite and 39 bovine bone hydroxyapatite from September 1995 to September 2007 were included. Charts were reviewed for preoperative diagnoses, type and size of implant, use of a wrapping material, and complications. Patients were followed for signs of inflammation, infection, extrusion, or other complications. RESULTS: There are more exposures of human bone hydroxyapatite (8.16%) and bovine bone hydroxyapatite (7.69%) than coralline hydroxyapatite implants (2.22%). Spontaneous healing of exposures occurred in 25% (2 of 8) of cases. Covering exposures with patch grafts underneath vascularized conjunctival flaps was the most successful method of surgical repair in 2 cases (25%). Chronic infection of the 2 exposed human bone hydroxyapatite leading to the removal of the 2 implants (1.5%). Conjunctival granulomas and late exposure developed in 2 and 3 patients after peg coupling respectively. There were no cases of implant migration or prolonged inflammation related to the covering material. CONCLUSION: Careful selection of surgical technique, implant type and size may help reduce the risk of severe complications.

Biocompatibilidade e comportamento de compósitos de hidroxiapatita em falha óssea na ulna de coelhos / Biocompatibility and behavior of hydroxyapatite on bone defect on rabbit's ulna

Avaliaram-se os compósitos de hidroxiapatita sintética e carbono (HAC) e hidroxiapatita sintética, carbono e fosfato biácido de sódio (HACF), ambos na forma sólida, como substituto ósseo em 36 coelhos adultos. Após protocolos anestésico e cirúrgico habituais, retirou-se um fragmento de aproximadamente 2cm de comprimento no terço médio da ulna esquerda. Os animais do grupo 1 receberam, em cada falha provocada, blocos de HAC e HACF, e os do grupo 2 somente HAC. Os do grupo 3 não receberam tratamento. Os animais foram submetidos a avaliações clínicas e radiológicas nos dias 8, 15, 30, 60, 120 e 180 de pós-operatório. Nas mesmas datas, dois animais de cada grupo foram sacrificados e deles colheu-se material para histologia. Observou-se evolução normal da regeneração óssea em todos os animais, sendo mais precoce nos dos grupos que receberam os compósitos. O uso de HAC e HACF na ulna de coelho mostrou-se um método eficiente, não apresentando sinais de infecção e nem evidência de rejeição.

Implantes de hidroxiapatita e osso liofilizado em deformidades de face: relato de caso e revisäo da literatura / Hidroxiapatite implants and liophilized bone in face deformities: case report and literature review

Este é um relato de caso de um paciente que sofreu trauma facial, no terço superior de face, por acidente de moto. O trauma resultou em afundamento do osso frontal. O paciente foi tratado com implante de hidroxiapatita e osso liofilizado, obtendo resultado satisfatórios