Provisional restorative materials require good mechanical properties, such as sufficient flexural strength, to remain functional within the oral cavity. Developments in provisional materials have resulted in the production of bis-acryl resins with varying curing methods. However, their performance in a moist environment remains uncertain.

This in-vitro study aimed to assess the effect of aging by storage on the flexural strength of self-cured and dual-cured bis-acryl resin materials.

Self-cured (Protemp 4) and dual-cured (Care C&B) bis-acryl resins were used in this study. A total of 40 bar-shaped specimens were fabricated and stored in distilled water at 37 ± 1°C. The control group was stored for 1 day (24 hours) while the treatment group was stored for 7 days prior to testing. Flexural strength was determined through a Three-Point Bending Test using a universal testing machine. Paired t-test was used to compare the mean flexural strengths of the bis-acryl resins after 1 day and after 7 days of storage. Independent T-test was used to compare the mean flexural strengths of the self-cured and the dual-cured bis-acryl resin materials within the same storage period.

The results showed that after 7 days of aging by storage in distilled water at 37 ± 1°C, both self-cured and dual-cured bis-acryl resin materials exhibited a statistically significant decline in mean flexural strength (p < 0.05). Within the same storage period, the difference in mean flexural strengths of the two materials was not statistically significant (p > 0.05).

Within the limitations of the study, it was found that aging by storage significantly decreased the mean flexural strength of the self-cured (Protemp 4) and dual-cured (Care C&B) bis-acryl resin materials. Future studies simulating actual intraoral conditions are recommended.