Desenvolvimento de um revestimento bioativo de alta adesão para aplicações em Implantodontia / Development of a high adhesion bioactive coating for implant dentistry purposes

Revestimento bioativo de alta adesão foi obtido por modificações físico-químicas na superfície do titânio para formar estruturas de multicamadas contendo TiO2 e fosfatos de cálcio Ca/P. Medidas de tração foram realizadas para quantificar as forças de interfaces, observadas perto de 10 MPa. A ativação das superfícies foi evidenciada por estimativas de energia livre, cujos efeitos são atribuídos tanto à difusão atômica quanto à polarização da superfície. Os testes mostraram a bioatividade e a qualidade da superfície para a aplicação tecnológica...

This paper reports the development of a high adhesion bioactive coating promoted by increasing titanium free surface energy. Through physical-chemical modifi cations, multilayer structures with titania (TiO2) and calcium phosphates (Ca/P) were formed. Adhesion strength measurements were performed to quantify the interfacial force aspects and results were near 10MPa. Surface activation was evidenced by free energy estimates, with results attributed to the atomic diffusion process. The bioactivity tests showed the quality of this surface for technological applications...

Aumento do rebordo alveolar por matriz óssea indutora / Matrix osseoindutor for alveolar ridge augmentation

A osseoindução tem sido aplicada por diversos meios com o objetivo de tratamento de defeitos ósseos e oferecer uma reabilitação adequada ao paciente. As matrizes formadas por osso bovino de granulação média é indicada para se usar como material de implante osseoindutor para aumento de volume de rebordo. Um protocolo para execução da reparação de atrofia severa da mandíbula foi realizado. Osso bovino de granulação média foi aglutinado com sangue do próprio paciente para formar uma matriz mineral com poros adequados para a proliferação endotelial. Com exames radiográficos pode-se observar que o osso bovino promoveu uma quantidade de osso neoformado o suficiente para encobrir todo o comprimento dos implantes. Esse osso novo favoreceu um aumento em sentido vertical, na altura do rebordo alveolar do osso retromolar. Apesar de ter uma neoformação menos acelerada quando comparada com o osso humano liofilizado esta terapêutica deve ser de conhecimento e se possível do domínio do implantodontista para poder aplicá-la quando necessária, para otimizar a colocação de implantes.

Osseoinduction has been applied in bone defects treatment and provide adequate rehabilitation to the patient. The bovine bone matrix, formed by the average grain, has been used as material for implant osseoinductor in alveolar ridge augmentation. A protocol for implementation of the severe atrophy jaw repair was performed. Bovine bone granulation average was agglutinated with patient’s own blood to form a matrix with pores mineral appropriate for endothelial proliferation.With X-rays can be observed that the bovine bone promoted a number of neoformed bone enough to cover the entire length of the implants. This new bone increased in the vertical direction, at the edge of the alveolar bone. Despite having a slower neoformation when compared to the human bone, professionals should know it and dominate it to apply it when necessary and to optimize the placement of implants.

Abutment cerâmico para prótese individual metalfree sobre implante: parafusada ou cimentada - demonstração laboratorial e clínica / Ceramic abutment for metalfree individual protesis supported implant: screw or cement - demonstration laboratory and clinical

A crescente exigência estética por parte dos pacientes tem levado ao desenvolvimento de novos materiais e técnicas restauradoras. Dentro desses novos conceitos e recursos protéticos, os pilares cerâmicos vêm ganhando popularidade por possibilitarem a elaboração de próteses implantossuportadas livres de metal e assim viabilizarem uma situação estética mais favorável, principalmente quando comparados aos abutments metálicos. Suas propriedades mecânicas são confiáveis, e sua biocompatibilidade com os tecidos também, o que os tornam uma alternativa viável nas reabilitações protéticas em regiões onde a estética é fundamental. Sendo assim, o presente trabalho apresenta um novo abutment cerâmico com características que possibilitam a realização de próteses cimentadas ou parafusadas livres de metal, com a demonstração de uma sequência laboratorial e clínica de uma restauração implanto-suportada confeccionada sobre o pilar cerâmico Ceraprep®.

The increasing demand of aesthetic by the patients, has led to the development of new materials and restorative techniques. Within these new concepts and features prosthetic ceramic pillars are gaining popularity because they allow for the development of implant-supported prostheses free of metal and thus continue to permit a more favorable aesthetic situation, especially when compared to metal abutments. Their mechanical properties are reliable, and its biocompatibility with the tissues as well, which makes it a viable alternative in prosthetic rehabilitation in areas where aesthetics are critical. Therefore, this paper presents a new ceramic abutment with features that enable the use of bolted or cemented prostheses free of metal, with the demonstration of a sequence of clinical laboratory and an implant-supported restoration fabricated on the ceramic abutment Ceraprep®.

Abutments de cerâmica de Y-TZP e compósito Al2O3-ZrO2 / Mechanical performance of Y-TZP/Al2O3 ceramic abutments

Abutment, também denominado pilar de fixação, é um material metálico ou cerâmico, instalado acima de um implante que provê suporte para próteses dentais. O sucesso significativo destas aumentou a demanda por melhores resultados estéticos e consequentemente resulta em pesquisas para o desenvolvimento de novos componentes, materiais e conceitos de tratamento. Atualmente, os implantes mais utilizados são aqueles a base de titânio e os abutments, que também eram fabricados com materiais metálicos, estão sendo substituídos por materiais cerâmicos como alumina e zircônia estabilizada com ítria. O presente estudo propôs-se avaliar as propriedades mecânicas de pilares cerâmicos estéticos a base de compósitos alumina-zircônia (Al2O3-ZrO2) e zircônia estabilizada (ZrO2 Y-TZP), através de ensaios mecânicos, a fim de verificar sua viabilidade de produção e comercialização para utilização em procedimentos odontológicos em reabilitação oral. Para tanto, obteve-se pilares cerâmicos a base de compósitos de ZrO2 e Al2O3-ZrO2 e submeteu-os a ensaios mecânicos de fadiga cíclica úmida e carregamento por compressão tangencial. Os resultados foram avaliados por meio de avaliações macroscópicas dos corpos de prova, sobrevida de ciclos e valores de resistência à fratura. Dentro das condições experimentais, os resultados obtidos demonstraram que há possibilidade de se obter pilares de ZrO2 e Al2O3-ZrO2, usinados industrialmente, com elevada resistência mecânica e durabilidade clínica quando corretamente instalados baseado em um planejamento minucioso. Apesar da realização dos ensaios em associação, cuja finalidade foi de se aproximar das condições in vivo, os ensaios laboratoriais apresentam limitações, como os vários tipos de forças intraorais.

An abutment is a metallic or ceramic material installed onto the implant providing support for fixed dental prosthesis. The significant success these dental restorations increased patient demand for better esthetic results, which resulted in research to develop new components, materials and treatment concepts. Currently, the most widely used implants are those based on titanium; the abutments, which were also made of metallic materials, are being replaced by ceramic materials such as alumina and yttrium-stabilized zirconia (ZrO2 Y-TZP). The purpose of this study is to evaluate the mechanical properties of ceramic abutments on the aesthetic composite alumina-zirconia (Al2O3-ZrO2) and stabilized zirconia (ZrO2 Y-TZP) by mechanical tests to verify its feasibility and production marketing for use in dental procedures. The abutments ceramic composites of ZrO2 and Al2O3-ZrO2 were submitted to mechanical tests of wet cyclic fatigue and loading by tangential compression. The results were evaluated by macroscopic evaluations of the specimens, survival after cycling and values of fracture resistance. Within the experimental conditions, the results showed that is possible to produce industrially abutments of ZrO2 and Al2O3-ZrO2 with high mechanical strength and clinic success when properly installed, based on careful planning. Although tests were applied to approach in vivo conditions, there are limitations such as several intra-oral forces.

Caracterização físico-química e biológica de enxerto ósseo bovino, Bonefill, em bioensaios - Parte 1 / Characterization physical-chemical and biological the bovine Characterization physical-chemical and biological the bovine bone graft, Bonefill in biogical assays - Part 1

A utilização de biomateriais para a recuperação de defeitos ósseos tem recebido uma grande atenção dos pesquisadores e clínicos, isso devido aos bons resultados obtidos nos últimos anos. Além disso, o mercado tornou-se muito promissor para as empresas que dominam essa tecnologia. No caso de produtos derivados de tecidos bovinos, a preocupação com a rastreabilidade da matéria-prima, o controle dos processos de fabricação e a garantia da biossegurança do material produzido devem ser pontos fundamentais na escolha do profissional. O objetivo do presente trabalho foi avaliar e caracterizar com ensaios laboratoriais o Bonefill, material produzido pela Bionnovation Biomedical S/A, a partir de osso cortical bovino. Teste de hipersensibilidade, avaliação do potencial de citotoxicidade, ensaio de toxidez aguda sistêmica, teste de irritação cutânea, ensaio de implante, teste de mutação gênica reversa e avaliação histológica de defeitos ósseos foram realizados para caracterização do material atendendo a exigência da ISO 10993. Os resultados demonstraram a eficácia do osso bovino Bonefill como material para preenchimento de defeitos ósseos em animais. Dentro das limitações do presente estudo, conclui-se a biocompatibilidade e biossegurança do produto como substituto ósseo em tratamentos regeneradores para tecido com técnica de enxertos ósseos.

The use of biomaterials for the repair of bone defects has received great attention from researchers and dentists that due to good results in last years. Moreover, the market has become very promising for companies that dominate the technology. In the case of products derived from bovine tissues, the concern with the traceability of raw materials, control of manufacturing processes and ensuring the biosecurity of the material produced should be key points in the choice of occupation. The purpose of this was assessed and laboratory tests to characterize the material produced by Bonefill Biomedical Bionnovation SA from bovine bone cortical. Evaluation hypersensitivity, test for in vitro cytotoxicity , test for systemic toxicity, test for irritation an delayed-type hypersensitivity, test implant, gene reverse mutation test and histological evaluation of bone defects were performed to characterize the material given the requirement of ISO 10993. The results demonstrated the effectiveness of bovine bone Bonefill as material to fill bone defects in animals. Within the limitations of this study, it is the biocompatibility and biosafety of the product as bone substitutes in treatments for regenerating tissue with a technique of bone grafts.

Tissue response around silicon nitride implants in rabbits.

The chemical and dimensional stability associated with suitable fracture toughness and propitious tribological characteristics make silicon nitride-based ceramics potential candidates for biomedical applications, mainly as orthopedic implants. Considering this combination of properties, silicon nitride components were investigated in relation to their biocompatibility. For this study, two cylindrical implants were installed in each tibia of five rabbits and were kept in the animals for 8 weeks. During the healing time, tissue tracers were administrated in the animals so as to evaluate the bone growth around the implants. Eight weeks after the surgery, the animals were euthanized and histological analyses were performed. No adverse reactions were observed close to the implant. The osteogenesis process occurred during the entire period defined by the tracers. However, this process occurred more intensely 4 weeks after the surgery. In addition, the histological analyses showed that bone growth occurred preferentially in the cortical areas. Different kinds of tissue were identified on the implant surface, characterized by lamellar bone tissue containing osteocytes and osteons, by a noncalcified matrix containing osteoblasts, or by the presence of collagen III, which may change to collagen I or remain as a fibrous tissue. The results demonstrated that silicon nitride obtained according to the procedure proposed in this research is a biocompatible material.

Síntese e caracterização de hidroxiapatita obtida pelo método da precipitação / Synthesis and characterization of hydroxiapatite formed by precipitation process

A utilização de substitutos ósseos para recuperação da função perdida é uma constante busca dentro da Odontologia e, mais especificamente, na Implantologia atual. Por isso os biomateriais têm recebido uma atenção muito grande por parte da comunidade científica internacional. O uso clínico de hidroxiapatita, principalmente em seio maxilar, para ganho de altura óssea e instalação de implantes dentários tem demonstrado resultados muito satisfatórios; tanto sem misturas ou quando utilizada agregada com outros materiais, tais como PRP (plasma rico em plaquetas), osso autógeno ou outros materiais para enxertia. O pó de hidroxiapatita, nesse estudo, foi preparado pelo método da precipitação. Microscopia eletrônica de varredura, espectroscopia na região do infravermelho e difração de raios-X foram utilizados para caracterização do material obtido. Casos clínicos foram realizados com objetivo de verificar a promoção de tecido ósseo para instalação de implantes. O resultado mostrou que o pó obtido é composto exclusivamente de hidroxiapatita não ocorrendo a precipitação de fases do sistema Ca-P. Estudos histológicos das áreas enxertadas e radiografias demonstraram que o leito receptor apresentou adequado crescimento de tecido ósseo, possibilitando a instalação dos implantes e posterior suporte de cargas mastigatórias.

The use of bone substitutes for recovery of lost function represents a constant search within the field of Dentistry, more specifically in contemporary Implantology. For this reason, biomaterials have received a great deal of attention from the international scientific community. The clinical use of hydroxyapatite, mainly in the maxillary sinus, for bone height gain and placement of dental implants has demonstrated very satisfactory results; either when used by itself or in conjunction with other materials, such as PRP (Platelet-Rich Plasma), autogenous bone, or other grafting materials. In this study, hydroxyapatite powder was prepared using the precipitation method. Scanning electron microscopy, infrared spectroscopy and x-ray diffraction were used to characterize the obtained material. Clinical cases were undertaken with the objective of verifying the promotion of bone tissue growth for implant placement. Results showed that the obtained powder is composed exclusively of hydroxyapatite, and that phase precipitation of the calcium phosphate system did not take place. Histological studies of the grafted areas and x-rays demonstrated that the receptor site displayed adequate bone tissue growth, making possible the placement of the implants and subsequent support of masticatory loads.

Titanium implant osseointegration with calcium pyrophosphate in rabbits.

The objective of this study was to characterize calcium pyrophosphate material, evaluate its in vitro cytotoxicity, and assess its ability to induce bone formation. X-ray diffraction (XRD) was used to determine crystallinity and phases present in material. Serial dilutions of extracts, from 10-day dissolution tests in modified Eagle's medium, were exposed for 24 h to mouse fibroblasts and cytotoxicity assessed via viable staining. In vivo performance was determined by placing Ti screws with and without calcium pyrophosphate agglutinated with marrow adipose tissue in the tibiae of eight rabbits. New bone formation around test and control implants was evaluated histomorphometrically by using three fluorochrome labels: alizarin, calcein, and tetracycline. After 8 postoperative weeks, the animals were killed and specimens were retrieved and processed for fluorescence and light microscopic analysis. Calcium pyrophosphate showed no cytotoxicity and the XRD showed that the main phase of the analyzed sample corresponded to beta-calcium pyrophosphate. The largest fluorochrome labeling area occurred during the fourth and fifth postoperative weeks, in both control and experimental groups. Histologically, the bone neoformation occurred in regions where the calcium pyrophosphate was resorbed. The morphometric analysis showed implants placed with calcium pyrophosphate resulted in smaller polyfluorochrome labeling area (p < 0.05).

Histological findings in titanium implants coated with calcium phosphate ceramics installed in rabbit's tibias.

Oral reconstruction using osteointegrated implants are widely indicated nowadays. The implant bone anchorage is very important for its functional stability. Thus, ceramic biomaterials are widely used as coatings of the implant surfaces to accelerate local osteogenesis. The purpose of this study is to assess the biocompatibility and the osteoconduction of two types of calcium phosphate ceramics used as titanium dental implant coatings. These implants were installed in rabbit tibia during an 8-week healing period. The light and fluorescent microscopy observations showed that the materials are biocompatible and that they have osteoconductive activities.

Bone remodeling analysis of various dental implant surfaces using polyfluorochrome sequential labeling in rabbit tibias.

The purpose of this study is to analyze the bone remodeling process after the placement of threaded implants with rough (RBM) and hydroxyapatite coated surfaces (HA) in rabbit tibias using polyfluorochrome sequential labeling. Histomorphometry was performed in order to quantify the amount of each label deposited during the healing period. This work demonstrates the possibility of periodic identification of apatite deposition during bone remodeling around titanium and ceramic implants. It has been concluded that the polyfluorochrome sequential labeling is an important tool for identification of bone remodeling after the insertion of titanium and ceramic implants inside rabbit tibias.

Effects of alcohol consumption on osseointegration of titanium implants in rabbits.

Alcohol consumption affects bone metabolism by impairing osteoblast proliferation and by increasing osteoclastic activity. The purpose of this study was to evaluate bone formation in alcohol-fed rabbits following the insertion of dental titanium implants. Animals were fed with 20% ethanol sugarcane brandy pre- and postoperatively (group 1), preoperatively only (group 2), and with water as control (group 3). During the postoperative period, rabbits received doses of polyfluorochrome labels (i.e., alizarin, calcein, and tetracycline). Rabbits were killed 8 weeks after the implant insertion. The polyfluorochrome-labeled bone areas in rabbits with alcohol consumption in pre- and postoperative (group 1) and preoperatively only (group 2) were significantly less (P <.05) than in the control group (group 3). The percentage of direct bone-to-implant contact was significantly less in pre- and postoperative (49.5%) and preoperative-only (49.2%) groups than in the control group (64.7%) (P <.05). Alcoholic rabbits demonstrated significantly less bone density and direct bone-to-implant contact.

Bone healing after the inferior alveolar nerve lateralization: a histologic study in rabbits (Oryctolagus cuniculus).

PURPOSE: The purpose of this article is to evaluate the bone healing around 2 different dental implant surfaces after the lateralization surgery of the inferior alveolar nerve (IAN) during an 8-week healing period in rabbits, and to check if there is any interaction between the implants and the nerve. MATERIALS AND METHODS: The IAN lateralization was performed in an experimental rabbit model. Eight adult female rabbits (Oryctolagus cuniculus) underwent the surgical procedure, and 1 implant was placed on each side of the mandible while the nerve was lateralized. On both sides, the nerve was repositioned directly in contact with the implant surface. With the intention of obtaining comparative results, smooth titanium implants were installed on the right side, and blasted Al2O3 ones were placed on the left. During the healing period, bone tracers were administered subcutaneously to check different periods of bone ingrowth. RESULTS: Histologic section, regardless of the studied surface, showed bone remodeling around the nerve, without contact between the nerve and the implanted surface. The bone blocks containing implants were histomorphometrically examined through computerized analysis, and the results obtained showed that the bone remodeling around the nerve occurred during the first weeks of healing. Through analysis of variance, the blasted Al2O3 implants showed at least 2.5-fold greater bone neoformation compared with the smooth titanium implants. CONCLUSIONS: Our results showed that there was no significant difference in the healing process concerning the nerve between the 2 studied surfaces. No interaction was detected between the nerve and the implants.