Evaluation of the amount of excess cement around the margins of cement-retained dental implant restorations: The effect of the cement application method

Abstract

Complete removal of excess cement from subgingival margins after cementation of implant-supported restorations has been shown to be unpredictable. Remaining cement has been shown to be associated with periimplant inflammation and bleeding. The purpose of this study was to investigate and compare the amount of excess cement after cementation with 4 different methods of cement application for cement-retained implant-supported restorations. Ten implant replicas/abutments (3i) were embedded in acrylic resin blocks. Forty complete veneer crowns (CVCs) were fabricated by waxing onto the corresponding plastic waxing sleeves. The wax patterns were cast and the crowns were cemented to the implant replicas with either an interim (Temp Bond) or a definitive luting agent (FujiCEM). Four methods of cement application were used for cementation: Group IM-Cement applied on the internal marginal area of the crown only; Group AH-Cement applied on the apical half of the axial walls of the crown; Group AA-Cement applied to all axial walls of the interior surface of the crown, excluding the occlusal surface; and Group PI-Crown filled with cement then seated on a putty index formed to the internal configuration of the restoration (cementation device) (n=10). Cement on the external surfaces was removed before seating the restoration. Cement layers were applied on each crown, after which the crown was seated under constant load (80 N) for 10 minutes. The excess cement from each specimen was collected and measured. One operator performed all the procedures. Results for the groups were compared, with 1 and 2-way ANOVA and the Tukey multiple range test (α=.05). No significant difference in the amount of excess/used cement was observed between the 2 different types of cements (P=.1). Group PI showed the least amount of excess cement in comparison to other test groups (P=.031). No significant difference was found in the amount of excess cement among groups MI, AH, and AA. Group AA showed the highest amount of excess cement. The volume of cement used for group PI specimens was significantly higher than for those in the other groups (P=.001). With respect to the volume of cement loaded into the test crowns no statistically significant difference was observed among other test groups (groups IM, AH, and AA). Group MI used the least amount of cement, followed by group AH and AA. No correlation between the amount of used cement and the amount of excess cement was found in any of the tested groups. Within the limitations of this in vitro study, the least amount of excess cement was present when a cementation device was used to displace the excess cement before seating the crown on the abutment (Group PI). With this technique a uniform layer of the luting agent is distributed over the internal surface of the crown leaving minimal excess cement when the restoration is seated.