Early osseointegration driven by the surface chemistry and wettability of dental implants

Objective The objective of this study was to investigate the impact of two different commercially available dental implants on osseointegration. The surfaces were sandblasting and acid etching (Group 1) and sandblasting and acid etching, then maintained in an isotonic solution of 0.9% sodium chloride (Group 2). Material and Methods X-ray photoelectron spectroscopy (XPS) was employed for surface chemistry analysis. Surface morphology and topography was investigated by scanning electron microscopy (SEM) and confocal microscopy (CM), respectively. Contact angle analysis (CAA) was employed for wetting evaluation. Bone-implant-contact (BIC) and bone area fraction occupied (BAFO) analysis were performed on thin sections (30 μm) 14 and 28 days after the installation of 10 implants from each group (n=20) in rabbits' tibias. Statistical analysis was performed by ANOVA at the 95% level of significance considering implantation time and implant surface as independent variables. Results Group 2 showed 3-fold less carbon on the surface and a markedly enhanced hydrophilicity compared to Group 1 but a similar surface roughness (p>;0.05). BIC and BAFO levels in Group 2 at 14 days were similar to those in Group 1 at 28 days. After 28 days of installation, BIC and BAFO measurements of Group 2 were approximately 1.5-fold greater than in Group 1 (

Cytocompatibility and biocompatibility of nanostructured carbonated hydroxyapatite spheres for bone repair

Objective The aim of this study was to investigate the in vitro and in vivo biological responses to nanostructured carbonated hydroxyapatite/calcium alginate (CHA) microspheres used for alveolar bone repair, compared to sintered hydroxyapatite (HA). Material and Methods The maxillary central incisors of 45 Wistar rats were extracted, and the dental sockets were filled with HA, CHA, and blood clot (control group) (n=5/period/group). After 7, 21 and 42 days, the samples of bone with the biomaterials were obtained for histological and histomorphometric analysis, and the plasma levels of RANKL and OPG were determined via immunoassay. Statistical analysis was performed by Two-Way ANOVA with post-hoc Tukey test at 95% level of significance. Results The CHA and HA microspheres were cytocompatible with both human and murine cells on an in vitro assay. Histological analysis showed the time-dependent increase of newly formed bone in control group characterized by an intense osteoblast activity. In HA and CHA groups, the presence of a slight granulation reaction around the spheres was observed after seven days, which was reduced by the 42nd day. A considerable amount of newly formed bone was observed surrounding the CHA spheres and the biomaterials particles at 42-day time point compared with HA. Histomorphometric analysis showed a significant increase of newly formed bone in CHA group compared with HA after 21 and 42 days from surgery, moreover, CHA showed almost 2-fold greater biosorption than HA at 42 days (two-way ANOVA,

Alveolar bone repair with strontium- containing nanostructured carbonated hydroxyapatite

Objective: This study aimed to evaluate bone repair in rat dental sockets after implanting nanostructured carbonated hydroxyapatite/sodium alginate (CHA) and nanostructured carbonated hydroxyapatite/sodium alginate containing 5% strontium microspheres (SrCHA) as bone substitute materials. Methods: Twenty male Wistar rats were randomly divided into two experimental groups: CHA and SrCHA (n=5/period/group). After one and 6 weeks of extraction of the right maxillary central incisor and biomaterial implantation, 5 μm bone blocks were obtained for histomorphometric evaluation. The parameters evaluated were remaining biomaterial, loose connective tissue and newly formed bone in a standard area. Statistical analysis was performed by Mann-Withney and and Wilcoxon tests at 95% level of significance. Results: The histomorphometric results showed that the microspheres showed similar fragmentation and bio-absorbation (p>;0.05). We observed the formation of new bones in both groups during the same experimental periods; however, the new bone formation differed significantly between the weeks 1 and 6 (p=0.0039) in both groups. Conclusion: The CHA and SrCHA biomaterials were biocompatible, osteoconductive and bioabsorbable, indicating their great potential for clinical use as bone substitutes

Histochemistry and immunohistochemistry evaluation of 5% strontium-containing nanostructure carbonated hydroxyapatite microspheres in bone repair

O objetivo deste estudo foi avaliar a reação tecidual envolvendo dois biomateriais (BM) diferentes: hidroxiapatita carbonatada nanoestruturada (cHA) e hidroxiapatita carbonatada nanoestruturada contendo 5% de estrôncio (SrcHA), através de análise histológica e imuno-histoquímica (IH) em levantamento de soalho de seio maxilar de coelhos. Dez coelhos da raça Nova Zelândia (ambos os gêneros) foram divididos aleatoriamente em dois grupos, de acordo com o período experimental e dois defeitos foram realizados bilateralmente no seio maxilar. O lado do defeito foi padronizado de acordo com o biomaterial: Grupo 1: cHA (o lado direito) e Grupo 2: SrcHA (lado esquerdo). Ao fim de 4 e 12 semanas cinco animais de cada grupo experimental foram eutanasiados e um bloco com a área de interesse foi removido. As colorações utilizadas para análise histológica foram Hematoxilina-Eosina (HE) e Tricrômico de Masson (TM) e para avaliação imuno-histoquímica os anticorpos anti-TRAP, anti-CD68 and anti-Runx 2. A análise microscópica exibiu ração tecidual similar entre os grupos estudados no primeiro período experimental. Ambos apresentaram reação de granulação (RG), células gigantes multinucleadas (CGMN) circundando o BM e osso neoformado. Em 12 semanas observou-se diminuição da RG e do BM sendo mais evidente no grupo cHA. Houve marcação imuno-histoquímica semelhante em ambos os grupos avaliados para os anticorpos anti-CD68 e anti-Runx 2 em 4 semanas, porém, em 12 semanas o grupo cHA exibiu menor positividade para tais marcadores. Não foram observadas células TRAP positivas em nenhuma amostra avaliada. Através deste estudo concluímos que não houve diferença na resposta tecidual entre os grupos no primeiro período experimental, além disso, a diminuição da quantidade de BM e resposta inflamatória foi tempo dependente. A expressão de CD68 e Runx 2 foi aparentemente maior no grupo SrcHA em 12 semanas o que poderia favorecer o reparo ósseo. Não foi possível avaliar a origem das CGMN através da marcação por TRAP.The aim of this study was evaluate by histological and immunohistochemistry (IH) analyses the tissue reaction surrounding two different biomaterials (BM): nanostructured carbonated hydroxyapatite (cHA) and 5% strontium-containing nanostructured carbonated hydroxyapatite (SrCHA) in rabbit sinus lift procedures. Ten New Zealand Rabbits (both genders) were randomly divided into two groups, according to the experimental period and two defects were prepared bilaterally in the maxillary sinus. The side of the defect was standardized according to the biomaterial: Group 1: cHA (right side) and Group 2: SrcHA (left side). Five animals were euthanized after each experimental period for 4 and 12 weeks and a block containing the area of interest removed. Hematoxylin-eosin (HE) and Masson’s Trichrome (MT) was used for histochemical evaluation and the primary antibodies anti-TRAP, anti-CD68 and anti-Runx 2 for immunohistochemistry analysis. Microscopic analysis showed a similar bone repair pattern between the groups in first experimental period, with similar amounts of granulation reaction (GR), multinucleated giant cell (MNGC) surrounded the BM and newly formed bone. In 12 weeks there was a significant decrease of GR and BM, this event more evident in cHA group. There was a similar immunostaining for CD68 and Runx 2 in both groups evaluated at 4 weeks, but at 12 weeks cHA group showed less positive cells for CD68 and Runx 2 than SrcHA group. There were no TRAP positive cells associated with different BM in both experimental periods. In conclusion, the inflammatory response decreased over the experimental periods as well as the amount of biomaterial. The CD68 and Runx 2 expressions were apparently higher in SrcHA group at 12 weeks which could promote bone repair. It was not possible to elucidate the origin of CGMN by IH.51f

Nevo Azul: relato de caso

A 44-years-old male patient, was referred to the stomatologist by the clinical dentist who detected the lesion on the palate. During anamnesis, the patient reported having used crack and cocaine and currently uses marijuana and alcoholic beverages, with a history of peeling and burning in the oral mucosa after use of “ether spray”. On the intraoral exam, pigmented macula was observed on the hard palate, well circumscribed, measuring approximately 4mm, with unknown evolution time. The diagnostic hypothesis was of melanocytic macule. An excisional biopsy was performed and the material was sent for microscopic analysis with histopathological diagnosis of blue nevus. The blue nevus is a benign pigmented lesion composed of nevus or melanocytic cells. It is the second most common melanocytic nevus in the oral cavity, being the palate the most frequent site. The relevance of this report consist on the fact that the blue nevus makes differential diagnosis with the melanoma, malignant neoplasm of melanocytic origin. Therefore, oral pigmented lesions with unknown evolution should be investigated to avoid this possibility.Paciente do sexo masculino, 44 ??anos, encaminhado ao estomatologista pelo dentista clínico que detectou a lesão no palato. Durante a anamnese, a paciente relatou ter usado crack e cocaína e atualmente usa maconha e bebidas alcoólicas, com histórico de descamação e queimação na mucosa oral após o uso de “spray de éter”. No exame intraoral, observou-se mácula pigmentada no palato duro, bem circunscrito, medindo aproximadamente 4mm, com tempo de evolução desconhecido. A hipótese diagnóstica foi de mácula melanocítica. Uma biópsia excisional foi realizada e o material foi enviado para análise microscópica com diagnóstico histopatológico de nevo azul. O nevo azul é uma lesão pigmentada benigna composta de nevo ou células melanocíticas. É o segundo nevo melanocítico mais comum na cavidade oral, sendo o palato o mais site freqüente. A relevância deste relato consiste no fato de que o nevo azul faz diagnóstico diferencial com o melanoma, neoplasia maligna de origem melanocítica. Portanto, lesões pigmentares orais com evolução desconhecida devem ser investigadas para evitar essa possibilidad

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