Machining accuracy of pediatric partial dentures using computer-aided design-computer aided manufacturing (CAD-CAM) system

Background: The complete digitalization of pediatric partial denture (PPD) is progressing rapidly and holds promise for pediatric dentistry. However, the machining accuracy of subtractive manufacturing (SM) and additive manufacturing (AM) produced by computer-aided design-computer aided manufacturing (CAD-CAM) systems has not been clarified. Therefore, we aimed to evaluate the machining accuracy of PPD manufactured by SM and AM. Methods: The machining accuracy was evaluated based on the accuracy of mucosal surface fitting of the three types of PPDs (control-PPD, SM-PPD, and AM-PPD) and the accuracy of the design data for SM-PPD (n = 6) and AM-PPD (n = 6). Standard Tessellation Language (STL) data of the digital design, the mucosa surface of the jaw model, and the polished surface of each PPD (control, SM, AM), as well as the scanned STL data of each PPD produced by CAD-CAM were superimposed using Artec Studio 12 Professional software (Luxembourg). The data were superimposed and displayed in a color map. The mean root mean square (RMS) values standard deviation (SD) (mm) of the fit between the mucosal surface fitting of the control-PPD and the PPD fabricated using the CAD-CAM system and the jaw model were statistically compared using the Kruskal-Wallis test (α = 0.05). The average RMS values of the two design data accuracies were statistically compared using the Mann-Whitney U test (α = 0.01). Results: No significant difference was observed in the accuracy of mucosal surface fitting in the control-PPD, AM-PPD and SM-PPD. The mean RMS values (SD) (mm), which indicate the precision of design data, were 0.09840 (0.00315) and 0.06389 (0.00371) for the AM-PPDs and SM-PPDs, respectively. SM-PPDs showed significantly higher accuracy than the AM-PPDs (p = 0.002). Conclusions: Both methods achieved acceptable mucosal surface fitting; however, SM-PPDs showed higher machining accuracy than AM-PPDs. These findings support the integration of SM-based CAD-CAM systems in pediatric prosthetic practice.

Additive manufacturing; Pediatric partial denture; Subtractive manufacturing; CAD-CAM

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