Hydrolytic and Color Stability of Resin Infiltration: A Preliminary in vitro Trial

Resin infiltration is an emerging technique for management of noncavitated lesions. This study evaluated the in vitro hydrolytic and color stability of the ICON® resin infiltration system (IC) in 42 extracted human teeth.

ICON® resin infiltration system was compared with dental adhesive (DA) and dental sealant (DS). The products were applied according to manufacturer's instructions. The baseline weight and color of the samples were recorded. Color was recorded by spectoral colorimeter. The samples were subjected to four experimental conditions: (1) group 1: Stored in lactic acid solution (pH 4.9) for 24 hours; (2) group 2: Thermocycled for 100 cycles (temperatures: 5°C, 55°C, and dwell time of 15 seconds); (3) group 3: Stored in 0.1 N sodium hydroxide solution (pH 12.48) for 14 days at 60°C; (4) group 4: Stored in phosphate-buffered saline solution (pH 7.2) at 37°C for 4 months. The weight and color were recorded again after removal of the samples from the experimental conditions. Two-factor analysis of variance models and Tukey's Honestly Significant Difference were performed to assess statistical differences among the groups. Scanning electron microscopy imaging was performed for samples from groups 1, 3, and 4.

All the samples showed loss of material and change in color. In the demineralizing solution, IC showed significantly greater weight loss (p = 0.032) and color change (p = 0.038) compared with DA. Dental Sealant showed significantly greater weight loss than IC (p = 0.027) after thermocycling. Teeth in group 3 exhibited the greatest weight loss (p < 0.001). Teeth in group 2 exhibited the greatest color change (p < 0.001).

All tested materials showed loss of retention and color change in the experimental conditions. Infiltration system exhibited greatest weight loss and color change in demineralizing solution. Dental sealant exhibited greatest weight loss upon thermocycling.

Clinicians should be cautious about the limitations of retention and color stability when considering resin infiltration for incipient lesions.