Effect of adding egg shell powder on the physicomechanical properties of Biodentine

Objective: This study evaluated the effect of incorporating 1 wt% egg shell powder (ESP) into Biodentine™ (BD) on its physicomechanical properties.Methods: Chicken eggs were ground and sterilized. Then, one wt% ESP was added to BD powder and mixed with BD liquid. The mixture’s pH and solubility were measured on 1, 3, 7, and 28 days. The setting time was determined using a Gillmore needle. Compressive strength was measured using a universal testing machine after 1 and 14 days. Surface chemistry was analyzed via FTIR spectroscopy. The findings were compared by independent samples t-test, the repeated measures ANOVA, and the Bonferroni post-hoc test (α = 0.05).Results: pH levels were comparable between the groups (P > 0.05). BD-ESP had a higher setting time than BD (P < 0.001). BD-ESP solubility was significantly higher than BD on day 1 (P = 0.001) but lower on days 7 (P = 0.006) and 28 (P = 0.001). On day 1, BD had higher compressive strength than BD-ESP (P = 0.027), whereas the compressive strength of both groups was comparable on day 14 (P = 0.099). FTIR analysis revealed an additional IR band associated with the phosphate band in the BD-ESP group, suggesting new apatite formation.Conclusions: Incorporating 1% ESP into BD resulted in lower initial solubility but higher solubility after a week and a month, likely due to increased ion dissolution. ESP incorporation also promoted additional apatite formation but negatively impacted the setting time and initial strength of BD.