Standardized study of carbonate apatite as bone substitute in rabbit’s tibia

5 p. : il., tab.The objective of this study was to investigate the bone repair of carbonate apatite (cHA)in comparison to hydroxyapatite (HA, control group) on osseous repair of rabbit’s tibia. Spheres (400-500 μm) of both materials were synthesized under 37ºC (cHA) and 90ºC (HA) and were not sinterized. Ethics Commission on Teaching and Research in Animals approved this project (CEPA/NAL 208/10). Six White New Zealand rabbits were submitted to general anesthesia and one perforation (2mm) was made in each tibia for implantation of cHA (left tibia) and HA spheres (right tibia). After 4 weeks all animals were killed and one fragment of each tibia with the biomaterial was collected with a total of 6 bone blocks for each group. Five bone blocks of each group were demineralized and 5-μm thick semi-serial sections were stain with Hematoxillin and Eosin and Trichromic of Masson for histological analysis and two fragments were collected and embedded in a methacrylate-based resin and cut into slices with ~30 μm and were analyzed by light microscopy (bright field and polarized microscopy). Both groups didn’t show the spheres after 4 weeks, newformed bone was observed from the periphery toward to the center of the surgical defect, which was even filled with connective tissue. Both materials are biocompatible, promote osteoconduction and showed to be resorbable

Accelerated Healing Period with Hydrophilic Implant Placed in Sheep Tibia

<div><p>Abstract The objective of this study was to evaluate the early osseointegration of two different implants surfaces, a sandblasted and acid-etched surface (TN) compared with same geometry and surface roughness modified to be hydrophilic/wettable by conditioning in an isotonic solution of 0.9% sodium-chloride (TA) through histological and histomorphometric analysis after sheep tibia implantation. Forty dental implants, divided in two groups (TN and TA) were placed in the left tibia of twenty healthy, skeletally mature Santa Ines sheep (n=5/experimental period). After 7, 14, 21 and 28 days post-implantation, the samples were removed and the sheep were kept alive. Analysis of resin sections (30 μm) allowed the quantification of bone area (BA) and bone-to-implant contact (BIC). TA group presented nearly 50% increase in BA at 14 days (p<0.001, ANOVA - Tukey’s post test) compared with 7 days. The TA presented higher values than the TN for BA and BIC at 14, 21, and 28 days after placement, stabilizing bone healing. TA hydrophilic surface promoted early osseointegration at 14 and 21 days compared to TN, accelerating bone healing period post-implant placement in sheep tibia.</p></div

Effect of Carbonate-apatite on bone repair in non-critical size defect of rat calvaria

5 p. : il., tab.The objective of this study was to investigate the bone repair of carbonate apatite (cHA) in comparison to hydroxyapatite (HA, control group), on osseous repair of non-critical size defect in rat calvaria. Spheres (400500μm) of both materials were synthesized under 37ºC (cHA) and 90ºC (HA) and were not sintered. Fifteen rats Wistar were submitted to general anesthesia and two perforations (4mm each) were made, one in each parietal bone, for implantation of cHA (left side) and HA spheres (right side). After 1, 3 and 6 weeks, five animals of each group were killed and the two fragments with the biomaterial were collected from the calvaria. The bone blocks with biomaterial were demineralized and 5μm thick semi-serial sections were done for histological analysis. The experimental group of 6 weeks did not show the presence of spheres of both biomaterials and few spheres were observed after 1 and 3 weeks. Histological analysis showed the connective tissue repairing the surgical defect after 1 week and newly formed bone after 3 weeks of surgery. Thus, we concluded both materials are biocompatible, promote osteoconduction and in all studied periods the biomaterials showed to be resorbable

Does Melatonin Associated with Nanostructured Calcium Phosphate Improve Alveolar Bone Repair?

Background and objectives: Calcium phosphates have been widely used as bone substitutes, but their properties are limited to osteoconduction. The association of calcium phosphates with osteoinductive bioactive molecules has been used as a strategy in regenerative medicine. Melatonin has been studied due to its cell protection and antioxidant functions, reducing osteoclastic activity and stimulating newly formed bone. This study aimed to evaluate the effect of topical application of melatonin associated with nanostructured carbonated hydroxyapatite microspheres in the alveolar bone repair of Wistar rats through histological and histomorphometric analysis. Materials and Methods: Thirty female Wistar rats (300 g) were used, divided randomly into three experimental groups (n = 10), G1: nanostructured carbonated hydroxyapatite microspheres associated with melatonin gel (CHA-M); G2: nanostructured carbonated hydroxyapatite (CHA); G3: blood clot (without alveolar filling). The animals were euthanized after 7 and 42 days of the postoperative period and processed for histological and histomorphometric evaluation. Kruskal&ndash;Wallis and Dunn&rsquo;s post-test were applied to investigate statistical differences between the groups at the same time point for new bone and connective tissue variables. Mann&ndash;Whitney was used to assess statistical differences between different time points and in the biomaterial variable. Results: Results showed a greater volume of residual biomaterial in the CHA-M than the CHA group (p = 0.007), and there were no significant differences in terms of newly formed bone and connective tissue between CHA and CHA-M after 42 days. Conclusions: This study concluded that both biomaterials improved alveolar bone repair from 7 to 42 days after surgery, and the association of CHA with melatonin gel reduced the biomaterial&rsquo;s biodegradation at the implanted site but did not improve the alveolar bone repair

Osseoinduction evaluation of hydroxyapatite and zinc containing hydroxyapatite granules in rabbits

6 p. : il.This study investigated the osteoinductive potential of granules of stoichiometric hydroxyapatite (HA) and 0.5% zinc containing hydroxyapatite (ZnHA) in intramuscular (IM) site of rabbit’s abdomen. The biomaterials were both used in granular form, with 75% porosity and particle diameter between 450 and 500μm, sintered at 1100°C. Both materials performed adequately on a multiparametric in vitro cytocompatibility assay, indicating their suitability for in vivo testing. After approval by the Ethics Commission on Teaching and Research in Animals, fifteen rabbits were submitted to general anesthesia, incision and tissue dilatation, and a small site was created for HA (right incision) and ZnHA (left incision) intramuscular implantation. The animals were killed after 2, 4 and 12 weeks for biomaterials and surrounding tissues removal. Histological analysis after 2 weeks revealed the presence of granulation tissue surrounding biomaterials with multinucleated giant cells and no newly formed bone for both materials. After 4 weeks there was fibrous tissue involving the material and few inflammatory cells. Following 12 weeks it was observed the presence of connective tissue surrounding the biomaterial, cellularized enough for the two experimental groups, but it was not observed the presence of bone matrix associated with the biomaterials. We conclude that both biomaterials are cytocompatible and did not present the property of osseoinduction after 12 weeks of implantation

In Vivo Evaluation of Permeable and Impermeable Membranes for Guided Bone Regeneration

Background: The degree of biodegradation and the inflammatory response of membranes employed for guided bone regeneration directly impact the outcome of this technique. This study aimed to evaluate four different experimental versions of Poly (L-lactate-co-Trimethylene Carbonate) (PTMC) + Poly (L-lactate-co-glycolate) (PLGA) membranes, implanted in mouse subcutaneous tissue, compared to a commercially available membrane and a Sham group. Methods: Sixty Balb-C mice were randomly divided into six experimental groups and subdivided into 1, 3, 6 and 12 weeks (n = 5 groups/period). The membranes (1 cm2) were implanted in the subcutaneous back tissue of the animals. The samples were obtained for descriptive and semiquantitative histological evaluation (ISO 10993-6). Results: G1 and G4 allowed tissue adhesion and the permeation of inflammatory cells over time and showed greater phagocytic activity and permeability. G2 and G3 detached from the tissue in one and three weeks; however, in the more extended periods, they presented a rectilinear and homogeneous aspect and were not absorbed. G2 had a major inflammatory reaction. G5 was almost completely absorbed after 12 weeks. Conclusions: The membranes are considered biocompatible. G5 showed a higher degree of biosorption, followed by G1 and G4. G2 and G3 are considered non-absorbable in the studied periods

Remoção de hábitos orais prejudiciais e restabelecimento da oclusão

Objetivo: realizar uma revisão integrativa da literatura sobre a indicação do clareamento dental em fumantes com o uso de peróxidos como agente clareador, relacionado à segurança do tratamento, eficácia, sensibilidade dentária, seu efeito na estrutura dentária e longevidade. Além disso, o efeito do creme dental branqueador em pacientes fumantes também foi pesquisado. Material e Métodos: as pesquisas nas bases de dados PubMed, LILACS e Scopus foram realizadas utilizando as seguintes palavras-chave: (Branqueamento OU clareamento ou clareamento dental) E (fumo OR fumante OR cigarrete), em inglês e português. Os critérios de inclusão foram: artigos publicados entre 2008-2018, estudos in vitro e clínicos e revisão da literatura. Resultados: 56 artigos foram encontrados. Após análise por título, 20 artigos foram selecionados. Após a leitura dos resumos, 6 artigos foram excluídos. 14 artigos foram lidos na íntegra, 6 foram excluídos de acordo com os critérios de inclusão / exclusão e 08 artigos foram abordados nesta revisão. Conclusão: 10% de peróxido de carbamida é um método seguro para o clareamento dental em fumantes. Peróxidos em diferentes concentrações foram eficazes no clareamento dental. Não houve diferença significativa entre fumantes e não fumantes em relação à sensibilidade. Os agentes branqueadores não causam mudanças permanentes na estrutura dentária. Em relação à longevidade, em um ano houve regressão da cor em fumantes e não fumantes, e a profilaxia foi eficiente na remoção da coloração extrínseca em pacientes tabagistas, estabilizando a cor obtida no clareamento. Os cremes dentais clareadores não foram eficazes na remoção de manchas