In vitro comparison of guide planes for removable partial dentures prepared with CAD-CAM-assisted templates, guiding rod templates, and freehand

Objectives: This study aimed to evaluate the accuracy of computer-aided design and computer-aided manufacturing (CAD-CAM)-assisted templates (CCAT), guiding rod templates (GRT), and freehand (FH) preparation of guide planes. Methods: Forty-five identical maxillary resin casts were divided into three groups, in which the guide planes of the two abutment teeth were prepared using a CCAT (n=15), GRT (n=15), and FH (n=15). The CCAT and GRT were digitally designed on a digital cast of virtually prepared guide planes and fabricated using three-dimensional printing (3DP) technology. To assess the 3D trueness, the prepared guide planes were digitally scanned and compared to the virtually designed guide planes. The angle deviation was measured to assess the trueness of the direction of the guide plane preparation. Shapiro-Wilk and Levene's tests were used to check the normality and equivalence of the variance of the data. The data were compared by using the Kruskal-Wallis H test (alpha=0.05). Results: The CCAT group exhibited significantly better 3D trueness (78.5 +/- 19.8 mu m) than the GRT group (211.3 +/- 42.4 mu m, p<0.05) and the FH group (198.9 +/- 44.3 mu m, p<0.05). Additionally, the CCAT group (1.31 +/- 0.50 degrees) showed significantly smaller direction trueness compared to the GRT (4.65 +/- 0.72 degrees, p<0.05) and FH (5.64 +/- 0.70 degrees, p<0.05) groups. Conclusions: The novel CAD-CAM-assisted template significantly improved the quality of the guide planes compared with the GRT and FH procedures. This enhancement suggests that removable partial dentures can be predictably inserted immediately after guide plane preparation.