Remineralisation of mineral-deficient dentine induced by experimental ion-releasing materials in combination with a biomimetic dual-analogue primer

Abstract

Objectives: Evaluate the remineralisation ability of experimental resin-based materials containing Fluoride-Doped Calcium Phosphate (FDCP), applied in mineral-deficient dentine in combination with a biomimetic dual-analogue primer.

Methods: Artificial dentine carious lesions were created in occlusal cavities of human molars. An experimental resin-based adhesive and flowable composite, containing FDCP (10wt% and 20wt%, respectively), were applied (±) with a biomimetic primer containing polyacrylic acid and sodium tripolyphosphate. A glass-ionomer cement and a conventional adhesive/composite were used as comparative materials. All specimens were submitted to chewing simulation in artificial saliva (AS). Subsequently, these were cut into slabs and submitted to Knoop microhardness testing and Raman spectroscopy (AS: 0, 15, 30 and 60 days). Further specimens were analysed through confocal scanning microscopy (AS: 0, 60 days). Total demineralised dentine and disc-shape materials were analysed through FTIR, SEM and EDX (Ca/P ratio) after prolonged contact in AS. Data were statistically analysed (two-way ANOVA and multiple comparison Bonferroni; α=0.05).

Results: Only the experimental FDCP materials induced a significant increase in microhardness after storage in AS, especially in those specimens pre-treated with the biomimetic primer, except at 50 µm underneath the interface. Raman and CLSM analysis corroborated such results. The ability of the experimental FDCP resin-based materials to induce apatite-like deposition was demonstrated through SEM-EDX and FTIR.

Conclusions: Resin-based materials containing FDCP can mineralise the mineral-deficient dentine, especially when combined with a biomimetic dual-analogue primer.

Clinical significance: Such Innovative ion-releasing restorative systems applied after selective caries removal might promote remineralisation of fully and partially demineralised dentine and increase the durability of dental restorations.

Keywords: Biomimetic; Calcium phosphate; Caries; Dentine; Fluoride; Ion-releasing materials; Remineralisation.