Biogenic amorphous calcium phosphate: a sustainable alternative for dentin remineralization.

BACKGROUND: Dentin demineralization weakens tooth integrity, requiring effective remineralization approaches. Amorphous calcium phosphate (ACP) is commonly used to deliver calcium and phosphate ions for dentin repair. However, synthetic ACP (SACP) often exhibits instability and limited antibacterial properties. In contrast, biogenic ACP (BACP), derived from eggshell waste, presents a sustainable alternative with potential advantages. OBJECTIVE: This study aimed to compare the remineralization potential of SACP and BACP by evaluating their ability to restore microhardness, tubular occlusion, and crystal deposit formation. Antibacterial efficacy against S. mutans and L. acidophilus was also assessed. METHODS: BACP was synthesized from eggshell waste using thermal and chemical processes, while SACP was commercially obtained. Both materials were characterized using SEM, EDX, FTIR, and XRD, with biocompatibility verified via MTT assay. Dentin specimens (n = 36) were demineralized (pH 4.5, 72 h) and divided into BACP, SACP, and control groups. Remineralization efficacy was assessed using pH-cycling, Vickers microhardness, SEM-EDX, and XRD. Antibacterial activity was evaluated using the agar diffusion method and biofilm disruption was analyzed through fluorescence microscopy against S. mutans and L. acidophilus. Statistical analysis was performed using one-way ANOVA with Tukey’s post-hoc test. RESULTS: SEM revealed that BACP had a more uniform, densely packed structure compared to SACP. Microhardness testing showed BACP-treated samples had the highest post-treatment hardness (59.97 HV), followed by SACP (53.80 HV) and control (42.30 HV). EDX showed a higher Ca/P ratio in BACP (1.64) compared to SACP (1.54), closely resembling hydroxyapatite. BACP exhibited superior antibacterial activity in both agar diffusion and biofilm disruption analyses. CONCLUSION: BACP, derived from eggshell waste, demonstrated superior remineralization and antibacterial potential, making it a promising alternative to SACP for dentin repair. CLINICAL TRIAL NUMBER: Not applicable.