Aging performance and bacteria adhesion of 3D-printed, CAD/CAM-milled, and conventional definitive denture resins

This study aimed to evaluate the performance of 3D-printed denture base resins (DBRs) compared with conventionally packed and milled DBRs, examine their biofilm formation and physical properties, and determine the viability of 3D-printed DBRs as a superior alternative in removable prosthodontics.

The DBR samples were fabricated using traditional packing (TRA), milling (MIL), and 3D printing (3DP) methods. All samples were serially polished with an abrasive paper. Biofilm formation was assessed using SYTO 9 and propidium iodide staining as well as confocal laser scanning microscopy. Color and dimensional stability were evaluated following immersion in artificial saliva, and volumetric changes were assessed after the samples were subjected to thermocycling (TC) and highly accelerated stress (HA) aging. Statistical analyses were conducted using one-way analysis of variance with post-hoc Tukey's honestly significant difference test (α = 0.05).

MIL exhibited the highest Aggregatibacter actinomycetemcomitans biofilm coverage (94.59%), whereas 3DP exhibited the lowest coverage (58.86%). All DBRs exhibited slight perceptible color changes after immersion in artificial saliva, with 3DP demonstrating the least dimensional changes (2.86%). Following TC and HA aging, all DBRs experienced a volume increase, with TC inducing greater volumetric changes (2.8%-3.9%) than HA (0.8%-2.4%); however, the difference was not statistically significant (P < 0.05).

The 3D-printed DBRs demonstrated superior resistance to biofilm formation, along with good color and dimensional stability. These properties indicate strong potential for enhanced hygiene maintenance, esthetics, and long-term clinical performance in denture applications.