Physico-Mechanical Properties of Polymeric Denture Base Material: Comparing Conventional Versus Two Digital Processing Techniques

Aim: The aim was to assess how various processing methods affect some physico-mechanical properties of polymethyl methacrylate (PMMA) denture base material. In addition, the impact of 1-month aging was evaluated regarding surface roughness and microhardness. Materials and methods: 120 specimens were divided into three main groups based on their processing technique as follows; conventional heat cure, computer aided designed/ computer aided manufactured (CAD/CAM) milled and three-dimensional (3D)-printed acrylic resin. The effect of processing on porosity percentage and water sorption and solubility was assessed (n=10/group/test). In addition, color stability was evaluated after specimens' exposure to Tea solution for 1 month (n=10). Surface roughness and Vicker micro-hardness were evaluated at baseline and after 1 month of artificial saliva storage in an incubator at 37̊C (n=10). Data was collected and statistically analyzed according to their distribution to evaluate the difference between the groups. Results: Processing techniques significantly affected porosity percentage and water sorption with milled group showing the least values followed by conventional then 3D-printed techniques. Negative solubility values were observed for all groups. The 3D-printed group changed color significantly more than the other groups. Roughness and hardness values were significantly different between all the groups at baseline and after aging. Aging adversely affected roughness of 3D-printed group. Aging showed a negative effect on hardness of all groups. Conclusion: The processing procedure impacts not only the physicomechanical qualities of the prosthesis, but also stability in the oral environment.