2018 Volume 30 Issue 4 Pages 477-485
Improvement of the dentin surface is an important factor in successful restorative or endodontic treatments because of the requirement for adhesion to dental tissue, or increased bonding strength. This study was undertaken to observe the radicular dentin surface contact angle during exposure to ultraviolet （UV） light from an excimer lamp. Additionally, we investigated the structural and mechanical properties of dentin after UV lamp irradiation. The roots of 30 bovine lower central incisors were sectioned 1.5mm below the cementoenamel junction, and a 1-mm-thick radicular dentin slab was cut from each tooth. Polished specimens were randomly divided into three groups: no treatment （n＝10）, irrigation with NaOCl and EDTA （3％ NaOCl for 1min, 17％ EDTA for 1min, then 3％ NaOCl for 1min; n＝10）, and xenon excimer UV irradiation for 180sec （n＝10）. Pure water was dropped onto the dentin slabs and water contact angles were immediately measured for each specimen. For nanohardness and Young’s modulus, the dentin at the center, between the outer surface and the pulp chamber, was measured. Results were statistically analyzed by one-way ANOVA and Tukey tests （P<0.05）. The contact angle of dentin exposed to endodontic irrigants was significantly lower than that of normal dentin. Furthermore, the contact angle of dentin exposed to excimer UV irradiation was significantly lower than that of dentin exposed to endodontic irrigants. Mean hardness and mean Young’s modulus measurements did not differ between the groups. UV-irradiated dentin exhibited increased surface wettability. However, UV irradiation did not change the mechanical or structural properties of dentin. Thus, excimer UV irradiation might be useful in endodontic treatment.
