Effect of artificial aging on mechanical and physical properties of CAD-CAM PMMA resins for occlusal splints

Abstract

PURPOSE This study aimed to assess and compare the color stability, flexural strength (FS), and surface roughness of occlusal splints fabricated from heat-cured acrylic resin, milled polymethyl methacrylate (PMMA)-based resin, and 3D-printed (PMMA) based-resin. MATERIALS AND METHODS Samples of each type of resin were obtained, and baseline measurements of color and surface roughness were recorded. The specimens were divided into three groups (n = 10) and subjected to distinct aging protocols: thermomechanical cycling (TMC), simulated brushing (SB), and control (without aging). Final assessments of color and surface roughness and three-point bending test (ODM100; Odeme) were conducted, and data were statistically analyzed (2-way ANOVA, Tukey, P <.05). RESULTS Across all resin types, the most significant increase in surface roughness (Ra) was observed after TMC ( P < .05), with the 3D-printed resin exhibiting the lowest Ra ( P < .05). After brushing, milled resin displayed the highest Ra ( P < .05) and greater color alteration (ΔE 00 ) compared to 3D-printed resin. The most substantial ΔE 00 was recorded after brushing for all resins, except for heat-cured resin subjected to TMC. Regardless of aging, milled resin exhibited the highest FS ( P < .05), except when compared to 3D-printed resin subjected to TMC. Heat-cured resin exposed to TMC demonstrated the lowest FS, different ( P < .05) from the control. Under control conditions, milled resin exhibited the highest FS, different ( P < .05) from the brushed group. 3D-printed resin subjected to TMC displayed the highest FS ( P < .05). CONCLUSION Among the tested resins, 3D-printed resin demonstrated superior longevity, characterized by minimal surface roughness and color alterations. Aging had a negligible impact on its mechanical properties.

The Effect of Build Angle and Artificial Aging on the Accuracy of SLA- and DLP-Printed Occlusal Devices

“…This finding is confirmed by the results of a study by Revilla Leon et al [ 49 ]. In general, there are several studies indicating an overall negative affect of aging on printable resins [ 14 , 18 , 37 , 39 , 53 , 54 ], and also one recent study that indicates that although there are negative effects on the mechanical properties, those are not significant [ 36 ]. Some other studies have proven the negative effect of aging on other 3D-printed objects, like complete denture bases and models [ 39 , 55 ].…”

“…Lutz described a volume loss of AM splints after artificial aging [ 18 ]. In addition, it has been shown that AM splints have a lower surface roughness after aging than SM [ 36 ]. However, a negative effect of artificial aging on mechanical properties of AM splints materials has also been described [ 26 , 37 ].…”