Purpose: To measure the retrieval force required to remove 1.5-mm–thick CAD/CAM zirconia copings cemented on zirconia (Zr) and titanium (Ti) stock implant abutments after a single application of erbium-doped yttrium scandium gallium garnet (Er:YSGG) laser.
Materials and Methods: A total of 60 monolithic zirconia copings were cemented on Zr and Ti implant abutments with either a resin-modified glass-ionomer (RelyX Luting Plus, 3M; Rx) or a zinc oxide eugenol cement (Temp-Bond, Kerr; Tb). These abutment coping specimens were randomly divided into 12 groups based on laser application (vs control [C]), abutment type (Zr vs Ti), cement (Rx vs Tb), and storage condition (dry [D] vs saline water [W]). Er:YSGG laser was applied at 6 W, 30% water–60% air, and 20 Hz (300 mJ/pulse energy) postcementation following a defined pattern. The force required to remove the cemented copings from their abutments was measured on a universal testing machine. Descriptive statistics, multifactor analysis of variance (ANOVA), and post hoc Tukey honest significant difference tests (α = .05) were performed.
Results: The mean peak force values at removal of the Zr abutment groups were 470.3 ± 151.33 N (Zr-Rx-C), 161.7 ± 19.29 N (Zr-Rx-D), 316.03 ± 95.24 N (Zr-Rx-W), 103.27 ± 24.53 N (Zr-Tb-C), 39.33 ± 6.21 N (Zr-Tb-D), and 20.33 ± 6.45 N (Zr-Tb-W); and of the Ti abutment groups were 349.80 ± 106.82 N (Ti-Rx-C), 84.63 ± 14.02 N (Ti-Rx-D), 177 ± 62.57 N (Ti-Rx-W), 54.77 ± 9.10 N (Ti-Tb-C), 22.67 ± 4.32 N (Ti-Tb-D), and 11.57 ± 2.30 N (Ti-Tb-W).
Conclusion: Within the limitations of this study, the following conclusions were drawn: Er:YSGG laser allows for easier removal of cemented zirconia copings with lower removal forces, with Ti abutment specimens requiring lower forces than Zr abutment specimens. No significant difference was seen between laser and control groups for Tb compared to Rx. Er:YSGG laser shows great clinical promise for predictable retrievability of cemented monolithic zirconia implant crowns, especially with stronger resin-based cement. With further clinical evidence, this could be very useful for clinicians to manage cement-retained implant crown complications.
