"Influência do método de remoção de cárie na resistência adesiva de um sistema autocondicionante" / Microtensile bond strength of self-etching adhesives to caries-affected dentine

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

New methods for carious dentine removal have been proposed, such as, lasers and chemo-mechanical. This in vitro study aimed to evaluate the influence of caries removal methods (steel burs, Er, Cr: YSGG laser and Carisolv) on microtensile bond strength of self-etching adhesive systems. 50 extracted carious human molars were ground to expose flat surfaces where caries lesion was surrounded by normal dentine. Teeth were divided into 5 groups (n=10), with 50 original data, according to the removal method used: G1 - no removal; G2 - abrasive paper, G3 - steel burs; G4 – Er, Cr: YSGG laser (79, 61 J/cm 2 ) and G5 – Carisolv. Surfaces were bonded with Clearfil SE Bond, according to manufacturers’ instructions. A crown was built up using composite resin (Z250- 3M Brasil). After storage in water (24 h, 37 0 C), teeth were vertically serially sectioned into slices and trimmed into an hourglass shape with about of 1mm 2 area at the adhesion interface, that contained either infected, caries affected and normal dentine. Samples were tested in tension in a Instron machine at 0,5mm/min. Results showed that there is a significant difference between tested groups (p<0.005). Significantly lower results were found for caries infected dentin when compared to normal dentin values (G1). A significant difference was also found when caries affected and normal dentin were compared (G2, G3, G5). In normal dentin, G2 showed better bond strenght than another groups and G4 showed lower results than G3. G2 and G3 caries infected dentin removal methods showed better bond strength than the other groups when compared with G1 (caries infected dentin). The results indicated that: bond strength of a self-etching system to normal dentin was better than to caries infected (G1) and caries affected dentin after the use of abrasive paper (G2), round steel bur (G3) and Carisolv (G4). However, there was no difference between caries affected and normal dentin after the use of ErCr:YSGG laser (G4); abrasive paper is a laboratorial method to create smear layer and it was responsable for the best bond strength to normal dentin. The usage of Er, Cr: YSGG laser negatively altered adhesion of self-etching system on normal dentin when compared with round steel bur; infected dentin is not an adequate substrate for adhesion. Abrasive paper and round steel bur are the best caries infected dentin removal methods. There were no difference in bond strength to caries affected dentin when the other methods were used.

ASSUNTO(S)

self-etching systems infected dentine adesivo auto-condicionante micro-tração resistência adesiva microtensile bond strength adhesion dentina infectada adesão caries affected dentine dentina afetada por cárie

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