Objective  To explore the effect of onlays made by Chairside Economical Restoration of Esthetic Ceramics (CEREC) system in root canal repair of posterior tooth defect.

  Methods  Totally 100 patients (100 teeth) with posterior tooth defect were randomly divided into CEREC group and Ceramage group, with 50 cases in each group. The Ceramage group was treated with Ceramage polymerized porcelain onlays, and the CEREC group was treated with CEREC onlays. The satisfaction degree at immediate time point after repair, the repair effect at immediate time point after repair and one year after repair were compared between the two groups.

  Results  At immediate time point after restoration, there were no significant differences in the satisfaction degrees of prosthesis comfort, times and duration of treatment, prosthesis shape and color of prosthesis between the two groups (P>0.05). At immediate time point after restoration and one year after restoration, the success rate of restoration color in the CEREC group was significantly higher than that in the Ceramage group (P < 0.05). There were no significant differences in the success rate of periodontal status, edge closure, tooth integrity, secondary caries, retention, edge coloring and surface abrasion between the two groups (P>0.05).

  Conclusion  In the root canal repair of posterior teeth defect, CEREC onlays and Ceramage polymerized porcelain onlays have better restoration effect, but CEREC onlays have obvious advantages in the color of the restoration.