Impact of postpolymerization devices and locations on the color, translucency, and mechanical properties of 3D-printed interim resin materials

Juhea Chang; Yukyung Choi; Wonjoon Moon; Shin Hye Chung

doi:10.1016/j.prosdent.2022.08.018

Impact of postpolymerization devices and locations on the color, translucency, and mechanical properties of 3D-printed interim resin materials

J Prosthet Dent. 2022 Sep 27:S0022-3913(22)00514-5. doi: 10.1016/j.prosdent.2022.08.018. Online ahead of print.

Authors

Juhea Chang¹, Yukyung Choi², Wonjoon Moon³, Shin Hye Chung⁴

Affiliations

¹ Clinical Professor, National Dental Care Center for Persons with Special Needs, Seoul National University Dental Hospital, Seoul, Republic of Korea.
² Graduate Student, Department of Dental Biomaterials Science, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
³ Researcher, Department of Dental Biomaterials Science, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea; Research Fellow, Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Mass and Research Fellow, Harvard Medical School, Boston, Mass.
⁴ Associate Professor, Department of Dental Biomaterials Science, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea. Electronic address: den533@snu.ac.kr.

PMID: 36180261
DOI: 10.1016/j.prosdent.2022.08.018

Abstract

Statement of problem: How postpolymerization conditions affect the color and mechanical properties of 3-dimensional (3D)-printed prostheses is unclear.

Purpose: The purpose of this in vitro study was to evaluate the color, microhardness, and flexural strength of 3D-printed interim resin materials and to assess the effect of postpolymerization devices, polymerizing locations, and thermocycling on those properties.

Material and methods: A total of 270 disk-shaped specimens and 180 bar-shaped specimens were designed and 3D-printed with interim resin material (NextDent C&B). The specimens were postpolymerized in 1 of 3 devices (Group ND; NextDent, Group CR; Carima, and Group FL; Formlabs). Each group was divided into 3 circular zones of the polymerizing plate (central, medial, and lateral). Half of the specimens were subjected to 10 000 thermocycles. Color measurement, Vickers microhardness test, and 3-point flexural strength test were performed. Data were statistically analyzed by using the Kruskal-Wallis and Mann-Whitney tests (α=.05).

Results: The L∗a∗b∗ color coordinates exhibited significant differences among the 3 zones (P<.05). The color and translucency differences according to CIELab and CIEDE among the zones exceeded the clinically perceptible levels in group CR. ΔE and ΔTP between with and without thermocycling were significantly different among the devices (P<.05). Microhardness and flexural strength were significantly different among the zones for those affected by thermocycling (P<.05).

Conclusions: Different locations in postpolymerization devices influenced the color, translucency, and mechanical properties of 3D-printed interim resin materials. Thermocycling induced color and translucency changes and the mechanical weakening of postpolymerized resins, and the impact differed according to the device type.