Aging Effect on Mechanical Properties of Interim C&B Materials In Vitro

Objectives: To determine the effects of thermal accelerated aging on flexural strength and flexural modulus of conventional and CAD/CAM provisional crown and bridge restorative materials.
Methods: Six provisional crown and bridge materials were selected for this study. Three conventional resins: Jet Set 4 (Lang), Luxatemp (DMG), Protemp Plus (3M ESPE), and three CAD/CAM materials: ArtBloc Temp (Merz), Telio CAD-Temp (Ivoclar Vivadent), Vita CAD (Vita). Specimens of conventional materials were fabricated using a custom-made aluminum mold 25×2×2 mm. CAD/CAM blocks were sectioned with a circular diamond saw to the same dimensions. Subsequently all specimens were polished with 600-grit SiC abrasive paper. A total of 180 bar-shaped specimens were obtained (30 of each material) and were divided into three groups per treatment. Group 1 and 2 were immersed in 37^°C water for 24 hours, and 6 days, respectively. Group 3 was subjected to 5,000 thermal cycles between 5^°C and 55^°C in water with 35 seconds dwelling time. All specimens where tested for flexural properties using three-point bending protocol on an Instron 5566A at a crosshead speed of 0.5mm/min. Flexural strength (FS) and flexural modulus (FM) values were analyzed by one-way ANOVA and post hoc Tukey test.
Results: Flexural Strength (MPa) and Flexural Modulus (GPa) of provisional C&B materials selected for this study in three different treatments are shown in Tables 1 and 2.


Conclusions: No significant difference in FS and FM was found between the three treatments except for Luxatemp that shows an increase of both properties after thermal cycling and Protemp Plus increased FS after 6 days water storage at 37^°C.