Salivary enrichment with MaquiCPI-3 enhances acquired enamel pellicle properties and attenuates enamel mineral loss induced by microcosm biofilm.

OBJECTIVE: This study aimed to evaluate the interaction of a recombinant cystatin derived from Aristotelia chilensis, Maqui berry (MaquiCPI-3), with hydroxyapatite surfaces, its influence on salivary film formation and its potential to reduce biofilm-induced enamel demineralization. DESIGN: Protein adsorption and film stability were assessed using Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D) on hydroxyapatite-coated sensors, allowing real-time analysis of frequency and dissipation shifts. In vitro microcosm biofilm assays were performed using human saliva to simulate oral conditions, and enamel demineralization was quantified through transverse microradiography (TMR). Experimental groups included MaquiCPI-3 at 0.1, 0.5, and 1.0 mg/mL, Sugarcane Cystatin (CaneCPI-5) at 0.1 mg/mL, Phosphate-Buffered Saline (PBS) as the negative control, and 0.12% Chlorhexidine (CHX) as a positive control. RESULTS: MaquiCPI-3 at 0.5 mg/mL exhibited the highest adsorption and retention on hydroxyapatite, promoting the formation of a stable salivary film. QCM-D modeling revealed concentration-dependent differences in the viscoelastic properties of the adsorbed films. TMR analysis showed that MaquiCPI-3 at 0.5 mg/mL significantly reduced lesion depth compared with PBS, whereas the 0.1 and 1.0 mg/mL concentrations did not significantly differ from PBS. All MaquiCPI-3 concentrations significantly reduced mineral loss compared with PBS, with no significant differences among the three concentrations. CONCLUSIONS: MaquiCPI-3 demonstrated potential to reduce enamel demineralization through modulation of surface-associated salivary film properties. At 0.5 mg/mL, it exhibited protective effects approaching those observed for CHX, highlighting its potential as a promising alternative for caries prevention and enamel protection.