Occlusal teeth surface accuracy of milled complete dentures: a comparison between different manufacturing techniques

Leonardo Ciocca; Mattia Maltauro; Volodymyr Kravets; Roberto Meneghello; Angela Montanari; Lorenzo Breschi; Laura Anderlucci

doi:10.4047/jap.2025.17.4.185

Occlusal teeth surface accuracy of milled complete dentures: a comparison between different manufacturing techniques

J Adv Prosthodont. 2025 Aug;17(4):185-196. doi: 10.4047/jap.2025.17.4.185. Epub 2025 Aug 19.

Authors

Leonardo Ciocca¹, Mattia Maltauro², Volodymyr Kravets³, Roberto Meneghello⁴, Angela Montanari⁵, Lorenzo Breschi³, Laura Anderlucci⁵

Affiliations

¹ Oral and Maxillo-Facial Prosthodontics, Section of Prosthodontics, Department of Biomedical and Neuromotor Science, Alma Mater Studiorum University of Bologna, Bologna, Italy.
² Laboratory of Design Methods and Tools in Industrial Engineering, Department of Civil, Environmental and Architectural Engineering, University of Padua, Padova, Italy.
³ Department of Biomedical and Neuromotor Science, Alma Mater Studiorum University of Bologna, Bologna, Italy.
⁴ Department of Management and Engineering, University of Padua, Vicenza, Italy.
⁵ Department of Statistical Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy.

Abstract

Purpose: This study aims to compare the occlusal trueness and precision of teeth manufactured using two modern digital milling processes.

Materials and methods: A total of 38 complete dentures (CDs) were fabricated and analyzed. CDs in Group 1 (monolithic) (n = 19) were produced using a monolithic bicolor resin disk, whereas in Group 2 (oversize) (n = 19) were fabricated using the oversize process, which involves two separate resin disks of different colors. Two investigation methods were developed to evaluate trueness and precision: cusp area analysis and cusp vertex analysis. The study included three levels of analysis: a comparison of the two measurement methods, an evaluation of the monolithic versus oversize processes, and an assessment of under- and overcontouring inaccuracies.

Results: Statistical analysis using the Welch two-sample t-test, the non-parametric Wilcoxon signed-rank test, and the modified signed-likelihood ratio test (SLRT) revealed a statistically significant difference (P < 2.2 × 10^-16) between the two measurement methods (vertex vs. area) for both the monolithic and oversize groups, with the vertex method demonstrating greater accuracy. The analysis of over- and undercontouring inaccuracies revealed that 55% of the surface for the monolithic process exhibited overcontouring, compared to 99% for the oversize process, indicating a strong tendency toward surface roughness in the latter.

Conclusion: The monolithic milling method exhibited significantly superior accuracy compared to the oversize process (P < .05). Additionally, the Reference Point System (RPS) metrological method proved more reliable than the best-fit method for comparing complex structures, offering more accurate estimates of both trueness and precision.

Keywords: Accuracy; Complete denture; Computer aided manufacturing; Metrology; Milling machine.