Abstract: Objective: To observe the effect of treatment methods on the subgingival excessive cement of cement-retained implant crowns. Methods: 24 die stone models of mandibular posterior denture with bone level implant were used to cement crowns by four methods, namely, cement venting hole on the occlusal (group A), on the lingual surface (group B), isolation of PTFE on subgingival region of abutments (group C), and routine cementation (group D)(n=6). To collect the subgingival residual cement, the weigh was measured by electronic balance (mg). Analysis of one-way ANOVA was conducted with SPSS 17.0 (α=0.05). Results: The weight of subgingival excessive cement in group A and group C were less than those in group B and group D (P<0.05). Neither significant difference between group A and group C nor between group B and group D was observed (P>0.05). Conclusion: Compared with the cement venting hole on the lingual side and conventional bonding method, cement venting hole on the occlusal surface and the use of PTFE membrane to isolate the surface of abutment through the subgingival area during bonding can reduce the subgingival excessive cement effectively.

Key words: implant crown, subgingival excessive cement, cement venting hole, polytetrafluoroethylene membrane