RESUMEN
OBJECTIVE: The purpose of this study was to evaluate the microtensile bond strength of resin cement to a feldspathic ceramic after treating the surface with (a) hydrofluoric (HF) acid, (b) air abrasion, (c) Er:YAG laser irradiation, (d) Nd:YAG laser irradiation, and (e) HF acid etching after either air abrasion or laser irradiation. BACKGROUND DATA: It is unknown whether the laser application or its combination with another treatment method can be used as a tool to roughen the surface of a feldspathic ceramic in order to increase the bond strength between the resin cement and ceramic surface. MATERIALS AND METHODS: Forty feldspathic ceramic blocks (Ceramco(TM)) were prepared and divided into eight equal groups (n = 5) according to the following surface treatments: no treatment; etching with 9.5% HF acid; air abrasion with 50 µm Al(2)O(3); Er:YAG laser irradiation; Nd:YAG laser irradiation; air abrasion plus acid etching; Er:YAG laser plus acid etching; and Nd:YAG laser plus acid etching. After surface treatment, a silane-coupling agent and resin cement (Panavia F(TM)) were applied to each block. After storing for 24 h at 37°C and thermocycling between 5°C and 55°C for 1000 cycles, the microtensile bond strength of each specimen was measured. RESULTS: The highest bond strength was obtained from HF acid etching. HF acid etching after each laser irradiation significantly increased the bond strength (p < 0.05). However, HF acid etching after air abrasion decreased bond strength when compared to air abrasion alone. CONCLUSIONS: HF acid etching is the most effective surface treatment method for a feldspathic ceramic. However, laser irradiation with either the Er:YAG or Nd:YAG laser is not an adequate method for improving the bond strength of Panavia F. The laser application should be combined with HF acid etching.
Asunto(s)
Porcelana Dental/química , Ensayo de Materiales/métodos , Cementos de Resina/química , Grabado Ácido Dental/métodos , Abrasión Dental por Aire/métodos , Análisis de Varianza , Recubrimiento Dental Adhesivo/métodos , Materiales Dentales/química , Materiales Dentales/uso terapéutico , Porcelana Dental/uso terapéutico , Análisis del Estrés Dental , Humanos , Ácido Fluorhídrico/química , Ácido Fluorhídrico/uso terapéutico , Técnicas In Vitro , Terapia por Luz de Baja Intensidad/métodos , Cementos de Resina/uso terapéutico , Resistencia a la TracciónRESUMEN
In this study, the surface hardness of five light-cured composite resins were evaluated, namely: filled (Estelite), nanofil (AElite), unfilled (Valux Plus), hybrid (Tetric ceram), and Ormocer-based (Admira) composite resins. The microhardness values of composite specimens were measured at the top and bottom surfaces after 24 hours or 30 days of immersion in different solutions (tea, coffee, Turkish coffee, mouthwash, cola, and distilled water). Comparisons were made with univariate analysis of variance and Duncan's multiple range test. It was found that rough specimens of reinforced nano-hybrid composite material immersed in cola for 30 days had the lowest surface hardness (33.20), whereas rough specimens of hybrid composite material immersed in cola for 24 hours had the highest surface hardness (156.00). In both tea and coffee, the top surfaces tended to be harder than the bottom ones. In conclusion, the five different materials exhibited different hardnesses, and that the hardness values of composite materials were statistically different in different immersion solutions.