Abstract: Objective To compare the marginal fit between CAD/CAM zirconia custom abutments of different brands and Ti-base. Methods CAD/CAM system was used to fabricate three groups (KaVo, Nissin and Upcera) of zirconia custom abutments and each with five samples. The marginal gap (MG) was evaluated by scanning electron microscope (SEM) for comparing the marginal fit. Results The mean MG value was (10.25±6.25) μm in Nissin group and (9.87±5.48) μm in Upcera group, which were significantly different from (7.19±2.98) μm in KaVo group (P<0.05). No significant differences were observed between the mean MG values in Nissin and Upcera groups (P>0.05). Conclusion Different CAD/CAM materials directly affect the fit between custom abutments and titanium base. As for the marginal fit, KaVo was much better than Nissin or Upcera.

Key words: CAD/CAM, custom abutment, marginal fit