A new approach for Y-TZP surface treatment: evaluations of roughness and bond strength to resin cemen.

OBJECTIVE: This study aims to evaluate the effect of sonochemical treatment on the surface of yttria-stabilized tetragonal zirconia (Y-TZP) before and after the final sintering. MATERIAL AND METHODS: Twenty-eight Y-TZP discs were divided into four groups (n=7), according to surface treatment: PRE: pre-sintering sonication with 30% nominal power for 15 min; POS: post-sintering sonication with 30% nominal power for 15 min; JAT: air abrasion with 50-µm alumina particles; and CON: control group with no treatment. The POS and JAT groups were sintered before sonication and the PRE group after sonication. Surface roughness was analyzed using confocal microscopy, after which resin cement cylinders were placed on the surface of the Y-TZP discs and subjected to mechanical microshear bond strength test until fracture. Surface roughness and microshear bond strength values underwent ANOVA and the Tukey tests. RESULTS: The surface roughness values for the PRE group (299.91 nm) and the POS group (291.23 nm) were not significantly different (p≥0.05), statistically, and the surface roughness value of the JAT group (925.21 nm) was higher than those of PRE and POS (p=0.007) groups. The mechanical microshear bond strength test showed that there was no statistically significant difference between the groups (p=0.08). CONCLUSIONS: Therefore, the results showed that sonochemical treatment modifies the Y-TZP surface and is similar to the well-established sandblasting surface treatment regarding the strength of the bond with the resin cement.

A new approach for Y-TZP surface treatment: evaluations of roughness and bond strength to resin cemen

Abstract Objective This study aims to evaluate the effect of sonochemical treatment on the surface of yttria-stabilized tetragonal zirconia (Y-TZP) before and after the final sintering. Material and Methods Twenty-eight Y-TZP discs were divided into four groups (n=7), according to surface treatment: PRE: pre-sintering sonication with 30% nominal power for 15 min; POS: post-sintering sonication with 30% nominal power for 15 min; JAT: air abrasion with 50-μm alumina particles; and CON: control group with no treatment. The POS and JAT groups were sintered before sonication and the PRE group after sonication. Surface roughness was analyzed using confocal microscopy, after which resin cement cylinders were placed on the surface of the Y-TZP discs and subjected to mechanical microshear bond strength test until fracture. Surface roughness and microshear bond strength values underwent ANOVA and the Tukey tests. Results The surface roughness values for the PRE group (299.91 nm) and the POS group (291.23 nm) were not significantly different (p≥0.05), statistically, and the surface roughness value of the JAT group (925.21 nm) was higher than those of PRE and POS (p=0.007) groups. The mechanical microshear bond strength test showed that there was no statistically significant difference between the groups (p=0.08). Conclusions Therefore, the results showed that sonochemical treatment modifies the Y-TZP surface and is similar to the well-established sandblasting surface treatment regarding the strength of the bond with the resin cement.

Avaliação do tratamento de superfície por sonoquímica na resistência de união entre zirconia tetragonal policristalina estabilizada por ítria e cimento resinoso / Evaluation of surface treatment by sonochemical the bond strength between Yttria-Stabilized Tetragonal Zirconia Polycrystals and resin cement

O objetivo deste estudo foi avaliar o efeito do tratamento ultrassônico comotratamento de superfície da zircônia tetragonal policristalina estabilizada por ítria (YTZP)e depois da sinterização final, por meio de mensuração da rugosidadesuperficial e teste de resistência adesiva por microsisalhamento. Para tanto, discosde Y-TZP foram confeccionados e distribuídos em 4 grupos (n=7), conforme otratamento de superfície: 1-PRE: sonicação pré-sinterização; 2-POS: sonicação póssinterização;3-JAT: jateamento com partículas óxido de alumínio 50μm; 4-CON:sem tratamento. Os espécimes foram polidos e padronizados e posteriormentesubmetidos aos tratamentos de acordo com cada grupo. Os grupos POS, JAT eCOM foram sinterizados previamente ao tratamento e o grupo PRE após asonicação. Os grupos PRE e POS foram submetidos a tratamento em processadorultrassonico (Sonics VCX-750) em potência nominal de 30% durante 15 minutos. Ogrupo JAT foi jateado com partículas de alumínio 50μm a uma distância de 15 cm,enquanto o grupo CON não recebeu nenhum tratamento. A mensuração derugosidade superficial média (Ra) foi feita em Microscópio Confocal (MC), emseguida cilindros de cimento resinoso foram preparados e fotoativados na superfíciedo Y-TZP para serem submetidos ao ensaio mecânico de microcisalhamentorealizado em máquina de ensaios universal (INSTRON). Os valores de rugosidadesuperficial e resistência de união obtidos foram submetidos a ANOVA a um critério eteste de Tukey. Quanto aos valores de rugosidade superficial, o grupo PRE (299,91Mpa) e POS (291,23 Mpa) não apresentaram diferença estatística significante e ogrupo JAT (925,21 Mpa) mostrou maiores valores de rugosidade superficial quandocomparado ao PRE e POS. Para o teste de microcisalhamento não foramobservadas diferenças estatisticamente significantes entre os grupos. Por meio dosresultados obtidos foi possível observar que o tratamento ultrassonico é capaz dealterar a superfície da Y-TZP...

The objective of this study was to evaluate the effect of ultrasonic treatment assurface treatment of Y-TZP before and after the final sintering, through measurementof surface roughness and bond strength by microshear test. Therefore, Y-TZP discswere made and distributed in 4 groups (n = 7), as surface treatment: 1-PRE: Presinteringsonication; 2-POS: Post-sintering sonication; 3-JAT: air abrasion withaluminum oxide particles 50μm; 4-CON: no treatment. The specimens were polishedand standardized and subsequently submitted to the treatments according to eachgroup. The POS, JAT and CON groups been previously sintered to treatment and thePRE group after sonication. The PRE and POS groups were submitted to UltrasonicProcessor treatment (Sonics VCX-750) at 30% power for 15 minutes. The JAT groupreceived air abrasion with aluminum particles 50μm at distance of 15 cm, while groupreceived no treatment. The measurement of surface roughness was made inConfocal Microscope (MC), then resin cement cylinders were prepared andpolymerized in Y-TZP surface to be subjected to mechanical testing microshearperformed on universal testing machine (INSTRON). The values of surfaceroughness and bond strength were subjected to ANOVA and Tukey testAbout thevalues of surface roughness, the PRE group (299.91 MPa) and POS (291.23 MPa)showed no statistically significant difference and the JAT group (925.21 MPa)showed higher surface roughness values when compared to PRE and POS. Formicroshear test statistically significant differences were observed between thegroups. Through the results it was observed that the ultrasonic treatment is able tochange the surface of the Y-TZP and influence the bond strength to resin cement.

Abordagem multidisciplinar na restauração de um dente posterior extensamente destruído - relato de caso / Extensive posterior tooth restoration with a multidisciplinary approach - case report

Entre os tipos mais frequentes de restaurações dentárias, destacam-se as restaurações dos tipos compostas e/ou complexas em dentes posteriores, sendo comum a perda de uma ou mais cúspides, necessitando de uma abordagem multidisciplinar. No contexto atual da Odontologia minimamente invasiva, as resinas compostas têm destaque importante, pois possibilitam a substituição de restaurações insatisfatórias sem sacrificar excessivamente as estruturas dentárias sadias. Esta característica importante permite a realização de restaurações extensas em dentes desvitalizados. Este relato de caso clínico objetiva descrever uma técnica restauradora de um dente posterior envolvendo uma abordagem multidisciplinar (periodontia, endodontia e dentística restauradora), apresentando e discutindo a sequência dos procedimentos adotados. Neste caso clínico foi realizada uma cirurgia periodontal com intuito de possibilitar a posterior restauração direta em resina composta, associada a um retentor intrarradicular reforçado com fibra de vidro. Dessa forma, com a evolução das técnicas e materiais disponíveis para os clínicos gerais e especialistas, esta abordagem possibilita a devolução da estética e da função em um pequeno número de sessões clínicas, com custo reduzido quando comparado aos tratamentos restauradores indiretos.

Complex or composite posterior teeth restorations are among the most common types, and the loss of one or more cuspids is very frequent and often requires a multidisciplinary approach. Within the context of minimally invasive Dentistry, composite resins are widely used since they allow the replacement of unsatisfactory restorations, avoiding excessive wear of the healthy tooth structure. This enables extensive restorations in devitalized teeth. This report aims to describe a restoration technique applied on a posterior tooth through multidisciplinary approach (periodontics, endodontics and restorative dentistry), presenting and discussing the adopted procedures. In this clinical case, a periodontal surgery was performed in order to allow the subsequent direct composite resin restoration associated with an intra-radicular fiber post. Thus, with the evolution of techniques and materials available to the general practitioner and specialists, direct restorations allow aesthetical and functional restoration with a small number of clinical sessions with a lower cost when compared to indirect restorations.