Einfluss der "Etch-and-rinse" Technik auf die Dentinhaftung an sklerotischem Dentin

Aim of the Study Aim of the study was to evaluate the influence of the etch-and-rinse technique on bonding to sclerotic dentin. Material and method Fifty six extracted human teeth (incisors, premolars and molars) providing non-carious cervical lesions were cleaned and divided into 7 groups (n=8). All teeth were conditioned with two adhesives (AdhSE and Syntac) in different ways. The dentin was not prepared. Group 1-3 were treated with Syntac. Group 1 in a selective-etch technique with 30s enamel etching. Groups 2 and 3 were treated with etch-and-rinse technique. Group 2 received a 15s dentin and a 30s enamel etching, in group 3 enamel and dentin were etched for 30s. Groups 4-7 were treated with „AdheSE“. Group 4 was conditioned after manufacturer’s instructions, groups 5-7 were etched analogical to groups 1-3. Epoxy-resin replicas were made before and after thermomechanical loading (TML) in order to compare marginal quality under SEM magnification. Results and observations It could be shown that the etch-and-rinse technique with 30s dentin etching or the use of self-etching primers combined with 15 s dentin-etching produced best marginal integrity in dentin after TML (48.1% and 45.1%). Bond strength of the other groups in decreasing order were: self-etch with 30s etching (37.9%), self-etch without any further treatment (31.2% and 27.8%), etch-and-rinse with 15s etching time (18.0%) and finally selective-etch without any conditioning of dentin (10.8%). There was no gap formation seen before TML (100%). Conclusions Prolonged etching time is needed for bonding to sclerotic dentin in order to obtain adequate bond strength. 30 s etching is recommended when using the etch-and-rinse technique. When using self-etch adhesives, 15 s phosporic acid etching is needed before primer application, because the ability of dentin demineralization of self-etch adhesives is not enough to create adequate bond strengths.