Machine-driven simulation of removing luting agent remnants from implant surfaces: An investigator-independent assessment of cleaning protocols

Introduction To simulate removing luting agent remnants from crowns fixed onto implant-abutment analogs using a standardized machine-driven protocol including a scaler and air polishing or sonic. Material and methods A motor-driven device was constructed that controlled the rotational speed of the specimens, machining distance, contact pressure, and working time. A standardized layer of cement (Provicol, VOCO; Cuxhaven, G; Ketac Cem, 3MEspe; Seefeld, G; or Rely X Unicem, 3MEspe, Seefeld, G) was placed onto the finishing line of the crowns luted onto titanium-abutment analogs. The cement layer was scaled with a fresh titanium scaler maneuvered by the motor-driven device and treated with air polishing or sonic. Protocol 1: Scaling only for 20s, 40s, or 60s; n=20; protocol 2: 40s of scaling plus 20s of air polishing; protocol 3: 20s of scaling plus 40s of air polishing; protocol 4: 20s of scaling plus 40s of sonic; protocol 5: 40s of scaling plus 20s of sonic; protocols 2-5: n=10. Cement remnants were counted digitally as "percentage of remnants". Statistics mean, standard deviation, Bonferroni post hoc tests; α=0.05. Results Ketac Cem was easily removed by scaling only and Provicol by scaling and air polishing, but the self-adhesive resin composite cement Rely X Unicem was not removable with the device. Only remnants of Provicol could be significantly reduced by further treatment after scaling (p<0.001). Conclusion The presented motor-driven device enables reproducible investigations of various cleaning protocols and is thus useful to create an overview of cleaning protocols needed for the different types of cement.