Influence of Henna Addition on The Flexural Strength of Acrylic Denture Base Material: An In Vitro Study

Purpose : The purpose of this study was to evaluate the flexural strength of the acrylic denture base material modified with different concentrations of henna.   Materials and Methods: Sixty heat polymerized acrylic resin specimens were fabricated in dimensions 65×10×2.5 mm according to ADA specifications #12. Specimens were divided according to henna concentrations into 6 groups. One control group without henna addition while the other five groups were processed by adding henna in concentrations 1%, 2.5%, 5%, 7.5% and 10% of acrylic powder. After processing, specimens were finished, polished, and stored in distilled water at 37 oC for 48±2 hours prior to testing. The three-point bending test was used to measure the flexural strength using universal testing machine. The morphology of the fractured specimens was studied under a scanning electron microscopy (SEM). The independent sample t-test was used and p ≤ 0.05 was considered statistically significant. Results: The flexural strength significantly decreased with henna addition to PMMA denture base material (   P<0.05), and this decrease was in proportional to henna concentrations.   Conclusion: The flexural strength of acrylic denture base material negatively was affected by henna addition.