Optical properties of dental zirconia, bovine dentin, and enamel-dentin structures.

OBJECTIVE: To evaluate the optical properties and the relative translucency parameter of Ceramill ZI White (3Y-TZP) and Ceramill Zolid FX White (5Y-PSZ) zirconia ceramic systems and compare them with those of the bovine dentin and enamel/dentin structures. MATERIALS AND METHODS: 3Y-TZP and 5Y-PSZ zirconia ceramic systems were evaluated. A 0.5-mm-thick 3Y-TZP (3Y-NC.5), 0.5-mm-thick (5Y-NC.5), and 1.4-mm-thick (5Y-C.14) were used. A 0.5-mm-thick dentin specimens and 1.4-mm-thick enamel/dentin specimens (n = 5) were obtained from anterior bovine maxillary teeth. Scattering, absorption, transmittance, and albedo coefficient were calculated using Kubelka-Munk's model. Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney tests (p < 0.001), and goodness-of-fit coefficient (GFC). Relative translucency parameter differences were evaluated using translucency thresholds. RESULTS: Reflectance, scattering, absorption, and transmittance properties were wavelength dependent. Good matches (GFC ≥ 0.999) in spectral reflectance were observed between 0.5-mm-thick dentin and 1.4-mm-thick enamel/dentin, and 3Y-NC.5 and 5Y-NC.5. Scattering was the main optical extinction process during light interaction with zirconia and dental structures, as indicated by albedo coefficient. Translucency differences were acceptable only for 3Y-NC.5 and the dentin structure, and 5Y-C.14 and the enamel/dentin structure. CONCLUSIONS: Optical properties of 3Y-TZP and 5Y-PSZ dental zirconia differed from each other and from bovine dental structures. Nevertheless, 3Y-TZP showed similar relative translucency parameter to bovine dentin. CLINICAL SIGNIFICANCE: To achieve the best esthetic results in restorative dentistry, it is crucial for clinicians to know about the optical properties of 3Y-TZP and 5Y-PSZ and to be able to compare these properties with those of dental structures.

Effect of Aging on Fracture Load and Reliability of Cemented Glass-Ceramics.

PURPOSE: Lithium disilicate (LD) and lithium silicate (LS) glass-ceramics may show a different acid etching behavior and mechanical integrity after aging. This study evaluated the influence of aging on the fracture load and reliability of glass-ceramics after different etching protocols. MATERIALS & METHODS: Specimens were fabricated and divided according to the etching time (10% hydrofluoric acid (HF) for 20s, 40s, and 60s). Etched surfaces were examined under microscopy. The ceramics were resin cemented to a dentin analog material. Samples were tested after 24 h (I) (n=20) or stored in 37°C water for 1 year (A)(n=20). A compressive load (0.1 mm/min) was applied to the samples until failure was detected by acoustic emission. The influence of aging on the fracture load (Lf) was tested by 2-way ANOVA and Tukey tests (α=0.05). The characteristic fracture load (L0) and Weibull modulus (m) values were calculated. RESULTS: LS etching for 20 s resulted in the highest immediate Lf, which was significantly decreased after aging (P≤0.05). Water-storage had no effect in this glass-ceramic Lf etched for 40 and 60s (P0.05). For LD, the etching time had no significant effect on the immediate and aged Lf (P0.05). The Lf was significantly reduced after aging (A) for LD (P≤0.05). Radial cracks were the predominant failure mode. Surface topography was more regular after lower etching times for LD, at after higher times for LS. CONCLUSIONS: After 1-year water-assisted aging, the evaluated etching times had no influence on the load-bearing capacity and structural reliability of resin-bonded glass-ceramics.

Analysis of topography, flexural strength, and microstructure of a lithium-disilicate glass-ceramic after surface finishing.

Glass-ceramic restorations often require adjustments using coarse diamond burs (D) which have the potential to introduce critical defects at the surface from which a crack can initiate and propagate until fracture. Surface finishing using fine and ultra-fine burs (F), polishing (P), or glazing (G) have the potential to reduce or eliminate these defects. PURPOSE: This study investigated the influence of finishing, polishing, and glazing on the roughness, flexural strength, and microstructure of a lithium disilicate glass-ceramic (LD). MATERIALS AND METHODS: LD CAD-CAM blocks were cut into 96 discs (1.2 mm x 12 mm). After crystallization, a layer of glaze was applied to the discs surface. The specimens were randomly divided into eight groups (n=12) for different surface treatments: G- glaze (control), GD, GDG, GDP, GF GFG, GFP, and GDFP. Mean roughness (Ra), mean square height (Rq) and maximum roughness (Rz) were measured. The biaxial flexural strength test was performed in a universal testing machine at 0.5 mm/min. Microstructural analysis was performed using X-ray diffraction patterns (XRD). Differences on the roughness obtained in distinct groups was analyzed by Kruskal-Wallis and Bonferroni tests (α = 0.05). The flexural strength tests were compared by one-way ANOVA. RESULTS: Glazed groups (G, GDG and GFG) presented the lowest surface roughness, lower crystallinity, and higher flexural strength than the other groups. Although polishing and glaze presented similar surface roughness, polishing protocol decreased the flexural strength compared to the control group G. CONCLUSION: clinically adjusted LD glass-ceramic restorations should be reglazed whenever possible to improve strength.

Equipes de saúde bucal na estratégia da saúde da família em polo urbano do sul do Brasil / Oral health teams in the family health strategy in urban pole of southern Brazil

Introdução: a Estratégia da Saúde da Família (ESF) é uma política brasileira recente de gestão e execução dos serviços de saúde. Um dos alvos desta política é promover a saúde bucal. Para tanto, as equipes devem ser constituídas segundo normas do Ministério da Saúde, compostas por cirurgião-dentista e pelo menos um auxiliar. Objetivo: avaliar a composição das equipes de saúde bucal da ESF do município de Passo Fundo/RS/Brasil e comparar com as normas do Ministério da Saúde. Métodos: neste estudo transversal, a composição de 22 ESFs foi avaliada através de consulta ao Sistema de Informação de Atenção Básica (SIAB), referente ao biênio 2013-2014, e por aplicação de questionário para avaliar a estrutura das Equipes da Saúde da Família. Resultados: nenhuma das 22 ESFs apresentou equipe de saúde bucal completa. O único profissional identificado foi o cirurgião-dentista, presente em 17 das 22 ESFs (77%), integralmente pago com verba municipal, sem contrapartida federal. Não há uma padronização na carga horária do profissional odontólogo, diferente dos demais profissionais que compõem a atenção básica. Das ESFs regularizadas no SIAB, 20% não apresentam cirurgião-dentista em sua composição, ficando esta população desassistida em saúde bucal. Conclusões: as equipes de saúde bucal das ESFs do município de Passo Fundo/RS são incompletas e não seguem as normas Brasileiras.

Introduction: the Family Health Strategy (ESF) is a recent Brazilian policy of management and execution from health services. One of its targets is to promote the Oral Health. In order to achieve this the staffs shall be established accordingly to the Health Ministry rules, formed by a dental surgeon and at least one assistant. Objective: to evaluate the oral health teams structure of the ESF in the city of Passo Fundo/ RS/Brazil and contrast it with the Health Ministry rules. Methods: in this cross-sectional study, were valued the structure of 22 ESFs by looking at the Basic Health Care Information System (SIAB), referring to the biennium 2013-2014 and by applying a questionnaire to evaluate the ESF´s teams structure. Results: none of the 22 ESFs reported an Oral Health perfect team. The only professional identified was the dental surgeon, existing in 17 out of 22 ESFs (77%), paid in full by municipal funds with no federal financial reward. There is not a standard at dentists workload oppositely to other professional in SIAB. From the ESFs settled at SIAB 20% have no dental surgeon in its staff leaving people unattended in oral health. Conclusions: the oral health ESFs teams from the city of Passo Fundo/RS are incomplete and don´t obey the Brazilian regulation.

Reabilitação de maxila com implantes osseointegrados inclinados ­ relato de caso / Jaw rehabilitation with inclined osseointegrated implants - clinical case

Os implantes osseointegrados são considerados um dos maiores avanços na Odontologia atual. A reabilitação total da maxila é um desafio frente às exigências funcionais e estéticas. O objetivo deste trabalho é relatar um caso clínico com a reabilitação protética superior de uma paciente edêntula, por meio de prótese fixa implantossuportada, cujos implantes distais foram inclinados com o objetivo de diminuir a extensão dos cantiléveres. Foram inseridos seis implantes, onde os mais posteriores foram instalados com uma angulação aproximada de 30 graus, tornando a emergência das plataformas posicionadas o mais distal possível. Após o período de seis meses, iniciou-se a etapa protética com a confecção da prótese sobre implantes do tipo Protocolo Bränemark. Por se tratar de uma prótese total fixa, os implantes se comportam como componentes de uma estrutura única, uma vez que estão unidos pela infraestrutura metálica. Assim, as resultantes horizontais e oblíquas das forças mastigatórias não apresentam magnitude suficiente para gerar alterações nos tecidos peri-implantares. A reabilitação de maxila com o uso de implantes inclinados mostrou-se uma técnica viável do ponto de vista estético e funcional, pois minimizou o número de etapas do tratamento eliminando procedimentos cirúrgicos corretivos prévios à instalação dos implantes. A inclinação dos implantes distais diminuiu a extensão dos cantiléveres e proporcionou estabilidade adequada (AU).

Dental implants are considered one of the greatest developments in modern Dentistry. The total rehabilitation of the maxilla is a challenge facing functional and aesthetic requirements. The objective of this study is to report a case of upper prosthetic rehabilitation of an edentulous patient using implant-supported fixed prosthesis, whose distal implants were tilted in order to reduce the extent of the cantilevers. Six implants were inserted, where the most posterior were installed with an approximate angle of 30 degrees, making the emergence of platforms placed as distal as possible. After six months, it began the prosthetic step with the manufacture of the prosthesis on the type Protocol Bränemark implants. Since it is a full fixed prosthesis, implants components behave as a single structure, since they are united by the metal infrastructure. Thus, horizontal and oblique resulting from masticatory forces do not have sufficient magnitude to cause changes in the peri-implant tissues. Jaw rehabilitation using tilted implants proved to be a viable technique for both aesthetic and functional, minimizing the number of treatment steps eliminating previous corrective surgical procedures to implant placement. The slope of the distal implants decreased the length of the cantilevers and provided adequate stability (AU).

Análise de tensões por elementos finitos no conjunto implante: pilar cone morse e implante: tecido ósseo û revisão de literatura / Finite element analysis of the conjunct implant: pillar and bone:pillar morse taper û literature review

Os implantes dentários tornaram-se uma realidade na reabilitação bucal, e grandes avanços como as conexões cone morse são utilizados com sucesso na reposição de dentes, diminuindo drasticamente o número de problemas como afrouxamento de parafusos. Por outro lado, a literatura mostra que o íntimo contato da interface implante/intermediário permite que tensões sejam distribuídas diretamente ao osso adjacente e às estruturas a ele conectadas, sendo que tensões acima dos limites de tolerância podem gerar microdanos e reabsorção óssea. O objetivo deste trabalho foi realizar uma revisão de literatura em bases de dados e livros sobre a distribuição das tensões nas interfaces implante/pilar e osso/implante, através de estudos de elementos finitos. Concluiu-se pelos estudos revisados, que a influência da morfologia anatômica do local, a angulação do implante, o tipo de material dos parafusos retentores e as condições de carregamento biomecânico do sistema osso-implante são diretamente proporcionais à resposta do tecido ósseo circunjacente ao implante

Dental implants have become a reality in oral rehabilitation, and major advances such as morse taper connections are successfully used in the replacement of missing teeth, reducing considerably the number of problems such as screw loosening. However, literature shows that the contact of implant/abutment interface distributes the stress directly to the adjacent bone, whereas stresses above the tolerance limits can generate microdamage and bone resorption. The objective of this study was to perform a literature review in databases and books about the distribution of stresses in implant/pillar and implant/bone interfaces through finite element analysis. It was concluded that the influence of anatomic morphology of the site, the angulation of the implant, the type of material of the retainer screws and biomechanical loading conditions of the bone-implant system are directly proportional to the response of the bone tissue surrounding the implant.