Comparison of fracture strength, surface hardness, and color stain of conventionally fabricated, 3D printed, and CAD-CAM milled interim prosthodontic materials after thermocycling

Mesut Yıldırım; Filiz Aykent; Mahmut Sertaç Özdoğan

doi:10.4047/jap.2024.16.2.115

Comparison of fracture strength, surface hardness, and color stain of conventionally fabricated, 3D printed, and CAD-CAM milled interim prosthodontic materials after thermocycling

J Adv Prosthodont. 2024 Apr;16(2):115-125. doi: 10.4047/jap.2024.16.2.115. Epub 2024 Apr 24.

Authors

Mesut Yıldırım¹, Filiz Aykent², Mahmut Sertaç Özdoğan²

Affiliations

¹ Duaçınarı Oral and Tooth Health Hospital Bursa, Bursa, Türkiye.
² Department of Prosthodontics, Faculty of Dentistry, Ankara Yıldırım Beyazıt University, Ankara, Türkiye.

Abstract

Purpose: The purpose of this in vitro study was to investigate the fracture resistance, surface hardness, and color stain of 3D printed, CAD-CAM milled, and conventional interim materials.

Materials and methods: A total of 80 specimens were fabricated from auto polymerizing polymethyl methacrylate (PMMA), bis-acryl composite resin, CAD-CAM polymethyl methacrylate resin (milled), and 3D printed composite resin (printed) (n = 20). Forty of them were crown-shaped, on which fracture strength test was performed (n = 10). The others were disc-shaped specimens (10 mm × 2 mm) and divided into two groups for surface hardness and color stainability tests before and after thermal cycling in coffee solution (n = 10). Color parameters were measured with a spectrophotometer before and after each storage period, and color differences (CIEDE2000 [DE₀₀]) were calculated. The distribution of variables was measured with the Kolmogorov Smirnov test, and one-way analysis of variance (ANOVA), Tukey HSD, Kruskal-Wallis, Mann-Whitney U tests were used in the analysis of quantitative independent data. Paired sample t-test was used in the analysis of dependent quantitative data (P < .05).

Results: The highest crown fracture resistance values were determined for the 3D printed composite resin (P < .05), and the lowest were observed in the bis-acryl composite resin (P < .05). Before and after thermal cycling, increase in mean hardness values were observed only in 3D printed composite resin (P < .05) and the highest ΔE₀₀ value were observed in PMMA resin for all materials (P < .05).

Conclusion: 3D printing and CAD-CAM milled interim materials showed better fracture strength. After the coffee thermal cycle, the highest surface hardness value was again found in 3D printing and CAD-CAM milled interim samples and the color change of the bis-acryl resin-based samples and the additive production technique was higher than the PMMA resin and CAD-CAM milled resin samples.

Keywords: 3D printing; Aging; Computer-aided design, Polymethyl metacrylate; Flexural strength.