Effect of Surface Treatment of Two Ceramic Materials by Er, Cr:YSGG Laser Irradiation on The Shear Bond Strength to Resin Cement: "a Comparative in-Vitro Study" / Efeito do tratamento de superfície de dois materiais cerâmicos por Irradiação de laser Er, Cr:YSGG na resistência ao cisalhamento a cimento Resinoso: "um estudo comparativo in-Vitro"

Objective: The aim of this study is to assess the effect of Er,Cr:YSGG laser on the shear bond strength (SBS) and surface topography of two CAD/CAM ceramic materials bonded with self adhesive resin cement. Material and methods: sixty ceramic CAD/CAM discs were obtained, 30 lithium disilicate (IPS Emax) (Group LD), and 30 hybrid resin ceramic (Vita Enamic) (Group RC). The Slices were allocated into six groups (n=10) according to ceramic material and surface treatment; Group (LD-C): IPS Emax treated with 9% hydrofluoric acid (HF), Groups (LD-L1) and (LD-L2): IPS Emax treated with Er,Cr:YSGG, Group (RC-C): Vita Enamic treated with 9% hydrofluoric acid (HF), Groups (RC-L1) and (RC-L2): Vita Enamic treated with Er,Cr:YSGG laser. The laser parameters and irradiation protocol was 1.5 W (L1) and 2.5 W (L2). All samples were cemented with self-adhesive resin cement and thermocycled for 5000 cycles. The SBS was measured using a universal testing machine and the mean values (MPa) were analyzed using Two-way (ANOVA) (P ≤ 0.05) and Bonferroni's post-hoc test. Results: RC-C (16.55) showed highest SBS followed by LD-C (13.79), which revealed no statistically significant difference with RCP1 (12.33) and RC-P2 (11.2). The lowest SBS values were found with LD-P1 (2.7) and LDP2 (2.1). SEM analysis revealed Vita Enamic to have the highest surface roughness. Fracture pattern analysis showed adhesive failure with IPS Emax groups and mixed failure with Vita Enamic groups. Conclusion: Er,Cr:YSGG laser irradiation with the parameters used did not increase SBS of IPS Emax and Vita Enamic with composite resin compared to HF acid etching (AU)

Objetivo: O objetivo deste estudo é avaliar o efeito do laser Er,Cr:YSGG na resistência ao cisalhamento (SBS) e na topografia superficial de dois materiais cerâmicos CAD/CAM cimentados com cimento resinoso autoadesivo. Material e métodos: foram obtidos sessenta discos cerâmicos CAD/CAM, 30 de dissilicato de lítio (IPS Emax) (Grupo LD) e 30 de resina híbrida (Vita Enamic)(Grupo RC). Os discos foram alocados em seis grupos (n = 10), de acordo como material cerâmico e o tratamento de superfície; Grupo (LD-C): IPS Emaxtratado com ácido fluorídrico (HF) a 9%, Grupos (LD-L1) e (LD-L2): IPS Emaxtratado com Er,Cr:YSGG, Grupo (RC-C): Vita Enamic tratada com ácido fluorídrico (HF) a 9%, Grupos (RC-L1) e (RC-L2): Vita Enamic tratada com laser Er,Cr:YSGG. Os parâmetros do laser e o protocolo de irradiação foram de 1,5 W (L1) e 2,5 W (L2). Todas as amostras foram cimentadas com cimento resinoso autoadesivo e termocicladas por 5000 ciclos. A SBS foi medida usando uma máquina de ensaios universais e os valores médios (MPa) foram analisados usando (ANOVA) a dois fatores (P ≤ 0,05) e teste post-hoc de Bonferroni. Resultados: RC-C (16,55) apresentou maior SBS seguido por LD-C (13,79), que não revelou diferença estatisticamente significante com RCP1(12,33) e RC-P2 (11,2). Os menores valores de SBS foram encontrados comLD-P1 (2,7) e LD-P2 (2,1). A análise por MEV revelou que a Vita Enamic possui maior rugosidade de superfície. A análise do padrão de fratura mostrou falha adesiva nos grupos IPS Emax e falha mista nos grupos Vita Enamic. Conclusão: A irradiação com laser Er,Cr:YSGG com os parâmetros utilizados não aumentou a SBS de IPS Emax e Vita Enamic ao cimento resinoso em comparação com o condicionamento ácido com HF.(AU)

Perceived color shift of ceramics according to the change of illuminating light with spectroradiometer

PURPOSE: Perceived color of ceramics changes by the spectral power distribution of ambient light. This study aimed to quantify the amount of shifts in color and color coordinates of clinically simulated seven all-ceramics due to the switch of three ambient light sources using a human vision simulating spectroradiometer. MATERIALS AND METHODS: CIE color coordinates, such as L*, a* and b*,of ceramic specimens were measured under three light sources, which simulate the CIE standard illuminant D65 (daylight), A (incandescent lamp), and F9 (fluorescent lamp). Shifts in color and color coordinate by the switch of lights were determined. Influence of the switched light (D65 to A, or D65 to F9), shade of veneer ceramics (A2 or A3), and brand of ceramics on the shifts was analyzed by a three-way ANOVA. RESULTS: Shifts in color and color coordinates were influenced by three factors (P 5.5). When switched to A, CIE a* increased (Deltaa*: 5.6 to 7.6), however, CIE b* increased (Deltab*: 4.9 to 7.8) when switched to F9. CONCLUSION: Clinically simulated ceramics demonstrated clinically unacceptable color shifts according to the switches in ambient lights based on spectroradiometric readings. Therefore, shade matching and compatibility evaluation should be performed considering ambient lighting conditions and should be done under most relevant lighting condition.

Progress in strength, strength testing methods of all-ceramic dental materials / 国际生物医学工程杂志

All-ceramic dental materials could meet the requirements for extraordinary aesthetics and ex-cellent biocompatibility in vivo, thus are widely utilized in prosthetic dentistry. Since the all-ceramic materials have low strength reliability and the disadvantage is recently concerned, the relevant research has been the focus in the area. The purpose of this artical is to review the relevant studies and with focus on the factors that influence the strength including material component, microstructures and manufacture process, as well as strength improv-ing approaches such as ingredient alteration, fabrication optimization and surface treatment. As for various strength testing methods, all the existing test methods are compared and evaluated.