Wear properties of acrylic dental material 3D printed via digital light processing: Influence of process settings

Abstract

The digital light processing (DLP) is one of the additive manufacturing methods, renowned for its precision and efficiency, with wide-ranging applications, notably in dentistry. Recent advancements in photocurable resins and DLP technologies have profoundly influenced dentistry. Despite their common clinical use, some resins lack comprehensive empirical studies on their mechanical and wear properties. In addition, analyzing the wear resistance of dental materials manufactured via additive manufacturing is imperative for ensuring their prolonged durability and dependability within authentic oral settings. Profound comprehension of the manner in which these materials withstand abrasive forces ensures their capability to withstand the mechanical strains imposed by chewing and brushing activities, thereby preserving their structural robustness and functional efficacy. The aims of this research are to investigate the effect of DLP process parameter setting, including: layer thickness, exposure time, and light intensity, on the wear resistance of acrylate dental materials. Using a pin-on-disc apparatus, wear tests were conducted. A steel pin, with a diameter of 5 mm, moved linearly over the specimen surface under the speed of 15 m/min and applying a force of 20 N. Scanning electron microscopy (SEM) was employed to examine the worn surface and wear mechanisms. Additionally, Analysis of Variance (ANOVA) was utilized to assess parameter effects and correlations. The findings indicate that parameter configurations exert a considerable influence on wear resistance and represent a cost-effective avenue for enhancing the wear resistance of components produced through additive manufacturing. The results revealed a direct correlation between resin curing and wear resistance, with inadequate or excessive curing leading to increased wear rates. The samples with a layer thickness of 25 µm, exposure time of 7.2 s, and light intensity of 160 W/m2, exhibited the lowest wear rate (11 × 10−2 mm3/min). Conversely, samples with a layer thickness of 100 µm, exposure time of 2.8 s and light intensity of 160 W/m2, demonstrated the highest wear rate (55 × 10−2 mm3/min). Additionally, the analysis of variance confirmed correlations between parameters, noting a negative correlation between intensity and time parameters, and positive correlations among other inter-parameter correlations.