Comparative Remineralization Efficacy of Different Physical Forms of Chitosan in a Newly Developed Olive Leaf...

Plant-derived bioactive compounds and natural biopolymers are increasingly investigated as components of multifunctional remineralization systems. This in vitro study compared the remineralization efficacy of chitosan film, gel, and solution on bleached human enamel within an olive leaf extract-containing artificial saliva system. The novelty of the present study lies in the direct comparison of three physical presentations of chitosan-film, gel, and solution-within a common olive leaf extract-containing artificial saliva platform. Olive leaf extract was incorporated as a common component of the artificial saliva in all groups and was not evaluated as an independent experimental factor. Seventy-six sound human anterior teeth were used; 60 were randomly allocated to four groups (n = 15) for Vickers microhardness analysis, and 16 (n = 4/group) were evaluated by SEM-EDX. Following bleaching with 35% hydrogen peroxide, specimens underwent 28-day remineralization protocols. Microhardness was measured at baseline, after bleaching, and after remineralization. Bleaching significantly reduced microhardness, whereas remineralization significantly increased it in all groups (p < 0.001). Microhardness gain (ΔVHN) differed among groups (p < 0.001), with all chitosan formulations showing greater gains than the control (p < 0.05). The solution showed the greatest numerical ΔVHN and a significantly greater gain than the gel (p = 0.015), but not the film. EDX revealed significant between-group differences in Ca gain (p = 0.017) and Ca/P ratio change (p = 0.033). Chitosan enhanced post-bleaching enamel microhardness recovery, with solution and film formulations showing particularly favorable remineralization responses.