Investigation of Optimal Cement Space in 3D Printed 3-unit Resin Prosthesis: A Pilot Study

Abstract

Purpose: The purpose of this study was to investigate the optimal cement space in the 3D printed 3-unit resin fixed partial denture. Materials and Methods: A model was fabricated for mandibular premolar and molar implant abutments. Forty resin prostheses were fabricated using stereolithography (SLA) 3D printer. A cement space of 90 μm (CS 90) was given for 20 specimens and a cement space of 100 μm (CS 100) was given for 20 specimens. The groups of each cement space were divided into 10 groups by a layer thickness (50 μm and 100 μm) and a build orientation (0°, 30°, 45°, 60° and 90°). The prostheses were seated and scanned with micro-CT. Marginal, axial and occlusal gaps were measured and statistically analyzed using Kruskal-Wallis and Mann-Whitney U test (α = .05). Results: In CS 90 groups, marginal gap (MG) value was 88.43 ± 41.77 μm, mid axial gap (AX) value was 92.74 ± 58.43 μm, axio-occlusal angle gap (AN) value was 80.49 ± 56.97 μm and occlusal gap (OC) value was 166.75 ± 52.38 μm. In CS 100 groups, MG value was 69.12 ± 40.17 μm, AX value was 113.43 ± 64.20 μm, AN value was 92.99 ± 55.73 μm and OC value was 161.79 ± 50.40 μm. In CS 100 group, MG showed smaller value in comparison to CS 90 group (p < .05). Conclusion: For the SLA 3D printed 3-unit resin fixed partial denture, setting the cement space to 90 μm or less is not recommended due to the interference in seating.