Bond strength durability of direct and indirect composite systems following surface conditioning for repair
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Data
2007-11-16
Autores
Passos, Sheila Pestana [UNESP]
Özcan, Mutlu
Vanderlei, Aleska Dias [UNESP]
Leite, Fabiola Pessoa Pereira [UNESP]
Kimpara, Estevão Tomomitsu [UNESP]
Bottino, Marco Antonio [UNESP]
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Purpose: This study evaluated the effect of surface conditioning methods and thermocycling on the bond strength between a resin composite and an indirect composite system in order to test the repair bond strength. Materials and Methods: Eighteen blocks (5 x 5 x 4 mm) of indirect resin composite (Sinfony) were fabricated according to the manufacturer's instructions. The specimens were randomly assigned to one of the following two treatment conditions (9 blocks per treatment): (1) 10% hydrofluoric acid (HF) for 90 s (Dentsply) + silanization, (2) silica coating with 30-Ìm SiOx particles (CoJet) + silanization. After surface conditioning, the bonding agent was applied (Adper Single Bond) and light polymerized. The composite resin (W3D Master) was condensed and polymerized incrementally to form a block. Following storage in distilled water at 37°C for 24 h, the indirect composite/resin blocks were sectioned in two axes (x and y) with a diamond disk under coolant irrigation to obtain nontrimmed specimens (sticks) with approximately 0.6 mm2 of bonding area. Twelve specimens were obtained per block (N = 216, n = 108 sticks). The specimens from each repaired block were again randomly divided into 2 groups and tested either after storage in water for 24 h or thermocycling (6000 cycles, 5°C to 55°C). The microtensile bond strength test was performed in a universal testing machine (crosshead speed: 1 mm/min). The mean bond strengths of the specimens of each block were statistically analyzed using two-way ANOVA (α = 0.05). Results: Both surface conditioning (p = 0.0001) and storage conditions (p = 0.0001) had a significant effect on the results. After 24 h water storage, silica coating and silanization (method 2) showed significantly higher bond strength results (46.4 ± 13.8 MPa) than that of hydrofluoric acid etching and silanization (method 1) (35.8 ± 9.7 MPa) (p < 0.001). After thermocycling, no significant difference was found between the mean bond strengths obtained with method 1 (34.1 ± 8.9 MPa) and method 2 (31.9 ± 7.9 MPa) (p > 0.05). Conclusion: Although after 24 h of testing, silica coating and silanization performed significantly better in resin-resin repair bond strength, both HF acid gel and silica coating followed by silanization revealed comparable bond strength results after thermocycling for 6000 times.
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Palavras-chave
Hydrofluoric acid, Indirect composite, Microtensile test, Repair, Silica coating, hydrofluoric acid, resin, silane derivative, silicon dioxide, analysis of variance, dental bonding, dental care, dental etching, drug storage, methodology, randomization, surface property, tensile strength, tooth prosthesis, Analysis of Variance, Composite Resins, Dental Bonding, Dental Etching, Dental Prosthesis Repair, Dental Stress Analysis, Drug Storage, Hydrofluoric Acid, Random Allocation, Silanes, Silicon Dioxide, Surface Properties, Tensile Strength
Como citar
Journal of Adhesive Dentistry, v. 9, n. 5, p. 443-447, 2007.