Effect of Crown Design, Cement Type and Margin Depth on the Removal of Cement Remnants Around Single...

To assess the influence of crown design, cement type, and margin depth on the removal efficiency of residual cement around single implant-supported restorations.

Twelve mandibular models with a missing first molar were fabricated and provided with single implant analogs (centrally/distally placed) and two different crown designs (non-cantilever/cantilever). Three of each design had either a superficial (SM = -1 mm) or a deep (DM = -2 mm) submucosal margin. Crown restorations were made from CAD/CAM titanium-base abutments and monolithic zirconia (n = 120). Three different cements (glass ionomer [GI], polycarboxylate [PC], dual-curing resin cement [RC]) were used in a standardized way for crown cementation. Ten dentists removed excess cement using metal scalers. The volumetric values of residual cement were calculated (mm³). Statistical analyses assessed the effects of the investigated variables on residual cement volume (p < 0.05).

The overall analysis showed no significant differences in the volume of cement remnants between both crown designs (non-cantilever: 0.42 ± 0.96 mm³; cantilever: 0.52 ± 0.98 mm³; p > 0.05). For crown margin depth, a significantly higher cement volume for deeper margins (SM: 0.28 ± 0.62 mm³; DM: 0.68 ± 1.19 mm³; p < 0.05) was found. The highest volume of cement remnants was found in the non-cantilever_DM_RC (1.19 ± 1.83 mm³), whereas the lowest value was found in non-cantilever_SM_GI and cantilever_SM_GI (0.00 ± 0.00 mm³). While crown design alone showed no statistically significant effect, its interaction with cement type was associated with improved cement removal in the cantilever group.

Crown margin depth emerged as the dominant factor influencing cement removal. Although cement type also affected residual cement, with glass ionomer showing lower values overall, crown design did not provide a consistent advantage.