Abstract: Objective: To investigate the proximal contact loss between single implant-supported crown and the adjacent teeth in posterior region. Methods: A total of 147 patients who had single tooth missing in posterior region were chosen for the present study. The proximal contacts between implant-supported crowns and the adjacent teeth were ideal conformed by dental floss at delivery time. After 1 year, the proximal contacts of all surfaces were detected by the dental floss again and recorded with ideal, not tight enough, and open. The incidence of proximal contact loss was calculated. The differences of incidence between mesial and distal surfaces and between premolar and molar group were compared. The influencing factors were explored. Results: No mechanical complication was observed. 78 surfaces were recorded with not tight enough or open, with the incidence of 29.59%. The incidence in mesial surface, distal surface, premolar group and molar group were 26.53%, 32.65%, 18.18%, and 38.89%, respectively. The incidence between mesial and distal surface was not significant different, however, the incidence between premolar and molar group was significant different (P<0.05). Conclusion: Proximal contact loss between single implant-supported crown and the adjacent teeth in posterior region is quite common. Communication with patients and reducing influencing factors before treatment are necessary.

Key words: Implant-supported restoration, Proximal contact, Posterior region