Accuracy of teeth positioning in bonded three-dimensionally printed complete dentures: an in vitro study

While the mechanical and material properties of 3D printed denture components have been extensively studied, the accuracy implications of the assembly process, specifically the bonding of separately printed teeth onto the denture base, remain insufficiently investigated. Positional distortion introduced at this stage could potentially result in downstream occlusal discrepancies. This study therefore investigated the accuracy of different 3D printing materials, methods (monoblock versus assembled) and assembly configurations (complete arch versus segmented) in the fabrication of 3D printed dentures.

Four groups of dentures (M, T, F, S; n = 15) were fabricated. M and T were printed monoblock units using model resin and tooth-coloured resin, respectively. F and S involved separate printing of denture bases and teeth, followed by bonding. Teeth were fabricated as a full arch in F and in three segments in S. All specimens were produced under standardised conditions. Digitized samples compared to a reference model using a surface-matching software. Tooth positional deviations were assessed as a complete arch and in sextants. Data was analysed using two-way analysis of variance and post-hoc tests (α = 0.05).

For complete arch analysis, Groups M and T demonstrated significantly lower deviations than Groups F and S (p = 0.001), with no significant differences within monoblock or assembled groups (p > 0.05). Sextant analysis showed consistent findings across all regions, with monoblock groups demonstrating superior accuracy.

Monoblock 3D-printed dentures exhibited greater positional accuracy than assembled dentures. Although deviations were within clinically acceptable thresholds, further clinical studies are required to determine their impact on occlusion and patient outcomes.