Influence of Shortened Light-curing Duration on the Potential of Resin-based Surface Sealants to Prevent Erosion

To determine whether reducing the light-curing time of resin-based surface sealants influences their potential to prevent erosion, as well as their mechanical stability and degree of conversion.

240 bovine dentin samples were randomly divided into 10 groups (1-10). The 24 samples of one group remained unsealed and served as control. Three groups were sealed with Seal&Protect, another three groups with K-0184 (experimental sealant), and the remaining three groups with Syntac Classic. One group of each sealant was light cured for 10 s, another group of that sealant for 5 s, and the last group of the respective sealant for 2 s at 1014 mW/cm2. After 7-day water storage, the first measurement of sealant permeability was performed. The samples were stored in hydrochloric acid (pH 2.3) for 24 h and the dentin calcium release was measured by atomic absorption spectroscopy. Following thermomechanical loading (5000 cycles, 5°/50°C, 12,000 brushing strokes), the second measurement of sealant permeability was performed. Additionally, the sealants' degrees of conversion (DC) were determined by FTIR spectroscopy.

For the first and second measurements, no significant difference in the permeability of the sealants was observed when the light-curing duration was shortened. Additionally, no significant difference in the stability of the respective sealants was observed when light cured for different durations. Regarding DC, a significant influence of the light-curing duration was observed (p = 0.000).

Shortening the light-curing time has no influence on permeability and stability of the investigated sealants. However, short light-curing times (2 s or 5 s) decrease the DC of the tested sealants.