A Study on How to Remove Cement-fixed Implant Superstructure from Abutment

Abstract

The purpose of this study was to find a way to quickly remove the cement-fixed superstructure when it encounters a com plication. A zirconia superstructure and a titanium abutment were prepared from the CAD/CAM data used in clinical prac tice before, and an experiment was conducted with a gypsum model in which the implant body and the titanium abutment were fixed with a screw and the zirconia superstructure was fixed with cement on it. Regarding the method, the cement fixed zirconia superstructure and abutment were removed from the implant body as a mass using CAD data images, and the zirconia superstructure was removed from the titanium abutment using an auto furnace.

Resin-added glass ionomer cement or resin cement was used as the cement. Before the removal experiment, changes due to heat treatment of cement lumps were investigated. The temperature inside the auto furnace was set to 350 and 400℃ for the resin-added glass ionomer cement and to 400℃ for the resin cement, and the mooring times outside and inside the fur nace were set. After mooring in the furnace, the cement lumps were taken out, allowed to cool naturally, and pressed with how pliers. The state of the cement lumps at that time was classified into fine particles, crushed pieces, and impossible-to crush pieces.

The shortest mooring time (outside the furnace ＋ inside the furnace) for fine particles was 18 min (8 min ＋ 10 min) at 350℃, 6 min (0 min ＋ 6 min) at 400℃ for resin-added glass ionomer cement, and 10 min (0 min ＋ 10 min) at 400℃ for implant cement. In this shortest mooring time, the cement-fixed superstructure could be removed from the abutment, and suggesting that the removed superstructure and abutment could be reused.