OBJECTIVES: This in-vitro study aimed to evaluate the effect of hydrofluoric acid etching and airborne particle abrasion on zirconia bond strength, using three different types of cement. To assess the impact of hydrofluoric acid etching on zirconia surface roughness and investigate the effect of hydrofluoric acid etching on zirconia's surface topography, microstructure, and crystal structure. MATERIALS AND METHODS: Crown-abutment simulation systems were constructed, using a custom-made zirconia tapered ring model and tapered titanium pin-abutments. Twelve groups were included in the study and classified according to the surface treatment and type of cement used. Each group had 10 specimens for a total of 120 test specimens. The fully sintered zirconia ring was alumina particle abrasion (APA) treated with a 50-μm alumina and/or etched with 9.5% HF acid, solution for 1 minute. The Ti pin was APA treated with 125-μm alumina. Three different types of cement were used: one RMGIC (GC FujiCem Evolve) and two resin composite types of cement (Panavia SA Universal and Panavia V5). A cementing jig was used to standardize the cementation process of the titanium pins to the zirconia rings. An Instron was used to obtain the retention load values. The failure load between the zirconia ring and the titanium pin was determined using an axial pullout test and the values were statistically analyzed for the effects of etching treatment, APA treatment, and cement type using JMP Pro 16. Zirconia-disk specimens were constructed using a custom-made disk model. Thirteen groups were included in the study and classified according to the hydrofluoric acid etching concentrations, consistencies, and timing used. Each group had 3 specimens. The total specimen size was thirty-nine specimens. Disks were polished and etched using 5% HF, 9.5% HF, and 40% HF acid etching concentrations, gel, and solution consistencies, and for 1 and 15 minutes of etching time. Disks were examined with an SEM, X-Ray diffractometer, and a profilometer for microstructure, crystallography, and surface roughness, respectively. RESULTS: HF acid-etching treatment significantly increased retention load compared to non-etched groups. There was no significant difference in retention load between APA-treated and non-APA-treated groups. Groups cemented with Panavia V5 showed a higher retention load compared to GC FujiCem Evolve and Panavia SA Universal. There was no significant difference in the surface roughness among the etched groups and the control groups. Roughening of the crystal boundaries with irregularities and pits was observed under SEM. As etching time and concentration increased the surface became rougher and more irregular. There were no obvious crystal structure differences between the etched groups and non-etched groups. CONCLUSIONS: Significantly different retention loads were found among tested groups. Hydrofluoric acid etching increases the bond strength of zirconia and titanium, using resin composite cement. Using hydrofluoric acid etching to pre-treat the zirconia surface may be an alternative approach to obtain sufficient bonding strength.

Made available in DSpace on 2014-06-11T19:24:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-11-30Bitstream added on 2014-06-13T19:10:18Z : No. of bitstreams: 1 porto_ts_me_arafo.pdf: 998293 bytes, checksum: 6183c4e4dea84be0c45e2947766bf407 (MD5) / O objetivo deste estudo foi avaliar a superfície interna de dois sistemas cerâmicos, após diferentes tratamentos de superfície, avaliação essa feita por meio de rugosimetria e microscopia eletrônica de varredura. Foram utilizadas as seguintes cerâmicas: IPS Empress II (Ivoclar-Vivadent Alemanha) e InCeram Alumina (Vita Zahnfabrick - Alemanha). Foram confeccionadas 50 amostras em forma de pastilha para cada sistema cerâmico de acordo com as especificações dos fabricantes, armazenadas à temperatura ambiente para então serem submetidas ao tratamento superficial, a saber (n=10): sem tratamento (T0) (controle); Ácido fluorídrico (T1); Ácido fluorídrico associado ao jato de óxido de alumínio (T2); Sistema Cojet (T3); Laser Nd:YAG (T4). Para os resultados de rugosidade, padronizaram-se as medidas em Ra, sendo posteriormente realizada a análise estatística por meio de ANOVA e teste de Tukey (p<.001). Para ambos os grupos controle (T0) das cerâmicas testadas, as análises evidenciaram os valores de rugosidade mais inferiores; para o Sistema InCeram Alumina, os tratamentos, ácido fluorídrico (T1), Sistem Cojet (T3)e Laser Nd:YAG (T4), não tiveram diferença estatisticamente significante; já para o Sistema IPS Empress II, todos os tratamentos foram estatisticamente diferentes. As fotomicrografias em microscopia eletrônica de varredura mostraram características diferentes para os tratamentos peculiares para cada sistema cerâmico. Baseado nos dados obtidos pode-se concluir que, quanto ao IPS Empress II, o tratamento com ácido fluorídrico é suficiente, assim como o Sistema CoJet é para o InCeram Alumina. Outros estudos devem ser realizados para que se tenham parâmetros ideais para o tratamento a laser. / The present study aimed at evaluating the inner surface of two ceramic systems, after different surface treatments, performed by surface roughness tests and scanning electron microscopy (SEM). IPS Empress II (Ivoclar-Vivadent – Germany) and InCeram Alumina (Vita Zahnfabrick – Germany) were used. Fifty lozenge-shaped samples were made for each ceramic system according to the manufacturers’ specifications, and stored at room temperature prior to surface treatment; namely (n=10): non-treated (T0) (control); hydrofluoric acid (T1); hydrofluoric acid associated to airborne particle abrasion (T2); CoJet System (T3); Laser Nd: YAG (T4). Roughness measurement results were standardized in Ra. Analysis of variance (ANOVA) and Tukey test (p<.001) were used to perform the stastistics analysis. For both control groups of the tested ceramics, analyses revealed the lowest roughness values; for the InCeram Alumina System, treatments such as hydrofluoric acid (T1), CoJet System (T3) and Laser Nd:YAG (T4) did not present any statistically significant difference, while for the IPS Empress II System, all treatments were statistically different. Photomicrographs by SEM showed different characteristics for each ceramic system treatment. Based on the resulting data, it can be concluded that the hydrofluoric acid treatment suits the IPS Empress II System, as well as the CoJet System suits the InCeram Alumina System. Further research might be done in order to get ideal parameters for the laser treatment.

Orientador: Welingtom Dinelli / Co^orientador: / Banca: José Roberto Cury Saad / Banca: Mânio de Carvalho Tibúrcio / Resumo: O objetivo deste estudo foi avaliar a superfície interna de dois sistemas cerâmicos, após diferentes tratamentos de superfície, avaliação essa feita por meio de rugosimetria e microscopia eletrônica de varredura. Foram utilizadas as seguintes cerâmicas: IPS Empress II (Ivoclar-Vivadent Alemanha) e InCeram Alumina (Vita Zahnfabrick - Alemanha). Foram confeccionadas 50 amostras em forma de pastilha para cada sistema cerâmico de acordo com as especificações dos fabricantes, armazenadas à temperatura ambiente para então serem submetidas ao tratamento superficial, a saber (n=10): sem tratamento (T0) (controle); Ácido fluorídrico (T1); Ácido fluorídrico associado ao jato de óxido de alumínio (T2); Sistema Cojet (T3); Laser Nd:YAG (T4). Para os resultados de rugosidade, padronizaram-se as medidas em Ra, sendo posteriormente realizada a análise estatística por meio de ANOVA e teste de Tukey (p<.001). Para ambos os grupos controle (T0) das cerâmicas testadas, as análises evidenciaram os valores de rugosidade mais inferiores; para o Sistema InCeram Alumina, os tratamentos, ácido fluorídrico (T1), Sistem Cojet (T3)e Laser Nd:YAG (T4), não tiveram diferença estatisticamente significante; já para o Sistema IPS Empress II, todos os tratamentos foram estatisticamente diferentes. As fotomicrografias em microscopia eletrônica de varredura mostraram características diferentes para os tratamentos peculiares para cada sistema cerâmico. Baseado nos dados obtidos pode-se concluir que, quanto ao IPS Empress II, o tratamento com ácido fluorídrico é suficiente, assim como o Sistema CoJet é para o InCeram Alumina. Outros estudos devem ser realizados para que se tenham parâmetros ideais para o tratamento a laser. / Abstract: The present study aimed at evaluating the inner surface of two ceramic systems, after different surface treatments, performed by surface roughness tests and scanning electron microscopy (SEM). IPS Empress II (Ivoclar-Vivadent - Germany) and InCeram Alumina (Vita Zahnfabrick - Germany) were used. Fifty lozenge-shaped samples were made for each ceramic system according to the manufacturers' specifications, and stored at room temperature prior to surface treatment; namely (n=10): non-treated (T0) (control); hydrofluoric acid (T1); hydrofluoric acid associated to airborne particle abrasion (T2); CoJet System (T3); Laser Nd: YAG (T4). Roughness measurement results were standardized in Ra. Analysis of variance (ANOVA) and Tukey test (p<.001) were used to perform the stastistics analysis. For both control groups of the tested ceramics, analyses revealed the lowest roughness values; for the InCeram Alumina System, treatments such as hydrofluoric acid (T1), CoJet System (T3) and Laser Nd:YAG (T4) did not present any statistically significant difference, while for the IPS Empress II System, all treatments were statistically different. Photomicrographs by SEM showed different characteristics for each ceramic system treatment. Based on the resulting data, it can be concluded that the hydrofluoric acid treatment suits the IPS Empress II System, as well as the CoJet System suits the InCeram Alumina System. Further research might be done in order to get ideal parameters for the laser treatment. / Mestre