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Printing accuracy and post-mounting dimensional stability of 3D-printed hollow dental models with varying shell
Qiucen Wan1, Carme Riera2, Trang Thi-Ngoc Tran3
1Department of Prosthodontics and Dental Research Institute, Seoul National University School of Dentistry, Seoul, Republic of Korea.
Objectives:
This in vitro study aimed to evaluate the impact of shell thickness and the presence of a cross-arch stabilizing bar on the dimensional accuracy of three-dimensional (3D) printed hollow dental models, assessing both printing accuracy and post-mounting dimensional stability.
Methods:
Four types of maxillary models were designed: 1-mm shell with bar (T1-B), 1-mm shell without bar (T1-NB), 4-mm shell with bar (T4-B), and 4-mm shell without bar (T4-NB). Models were fabricated using a digital light processing 3D printer (n = 10 per group). All specimens were scanned before (pre-mounting) and after being filled with Type II dental plaster (post-mounting). Printing accuracy was assessed by comparing pre-mounting scans to the original computer-aided design files, and post-mounting stability was assessed by comparing post-mounting to pre-mounting scans. Deviations were quantified using surface analysis (root mean square) and linear measurements. Data were analyzed using either nonparametric tests or a robust two-way analysis of variance (α = .05).
Results:
Both shell thickness and the cross-arch bar significantly affected trueness and post-mounting stability (p < .05). The T1-NB group consistently showed the largest deviations for both printing accuracy (linear: 899.2 µm) and post-mounting stability (linear: 190.2 µm). The T4-B group demonstrated the smallest deviations and highest accuracy. The setting expansion of the plaster introduced measurable deviations, which were most pronounced in the T1-NB group.
Conclusions:
Shell thickness and reinforcement significantly affected the trueness and stability of 3D-printed hollow dental models. Thicker shells with a cross-arch bar demonstrated the highest accuracy and stability, supporting their use in prosthodontic applications requiring articulator mounting.
Clinical Significance:
Optimizing model base design is critical when 3D-printed hollow models are used, not only for ensuring printing accuracy but also for maintaining dimensional stability after articulator mounting. Adequate shell thickness and reinforcement ensure accuracy, whereas thin, unreinforced models risk distortion from plaster expansion, potentially compromising prosthodontic treatment outcomes.
