In vitro salivary pellicles from adults and children have different protective effects against erosion

We aimed at analyzing the protective effects of salivary pellicles, formed with saliva from adults or children, on enamel from permanent or deciduous teeth.

Ninety human enamel specimens (45 permanent premolars and 45 deciduous canines) were ground, and the outer 200 μm of enamel was removed. We divided the teeth into three further subgroups: no salivary pellicle (control), adult salivary pellicle (AP), and child salivary pellicle (CP). We collected stimulated saliva from adults and children and placed 160 μl of either saliva on enamel specimens from AP and CP, respectively. Control specimens received no saliva. Specimens were stored at 37 °C for 2 h and then submitted to an erosive challenge (10 mL; 1 % citric acid; pH 3.6; 25 °C, 1 min). Pellicle formation and erosion was repeated for a total of 4 cycles. After every cycle, relative surface reflection intensity (rSRI) and surface microhardness (rSMH) were calculated.

On permanent enamel, AP presented significantly better protective effects, with less rSMH loss (p < 0.001) and less rSRI loss (p < 0.001). On deciduous enamel, CP presented significantly better protective effects than AP and control (p < 0.05), for both measured parameters.

We conclude that pellicles from adults and children promote different erosion protective effects, where adult pellicle provides better protection for permanent enamel, and child pellicle promotes better protection on deciduous enamel.

The present results provide a better understanding toward the protective effect of salivary pellicle against dental erosion and brings light to one more factor involved in the erosion of deciduous teeth.