Non-invasive proximal adhesive restoration (NIPAR) compared to resin infiltration for treating initial proximal carious lesions.

Purpose: To compare a new technique of non-invasive proximal adhesive restoration (NIPAR) to the infiltration concept technique (ICON).

Methods: Extracted human posterior teeth with non-cavitated proximal carious lesions (ICDAS code 1-2) were cut vertically to obtain two symmetrical lesions. Group 1 (NIPAR):Half of the paired lesions surfaces (n=13) were abraded with metallic strips and etched with 37% H3PO4 for 120 seconds. Group 2 (ICON):The other half of the paired lesions' surfaces (n=13) were etched with 15% HCl gel for 120 seconds. All samples were then stained with rhodamine isothiocyanate (RITC). After ethanol drying and isolation of the cut surface, Group 1 samples were infiltrated with Scotchbond Universal for 180 seconds and coated with a thin film of Tetric flow. Group 2 samples were infiltrated with ICON infiltrant following manufacturer's instructions. After light curing, unbound rhodamine was bleached by immersion in 30% hydrogen peroxide for 12 hours. Remaining lesion pores were stained with sodium fluorescein solution. Samples were observed with confocal microscopy (CLSM) and the percentage of infiltration (area of resin infiltration/area of total demineralization ×100) was calculated using ImageJ.

Results: 11 samples out of 13 showed larger infiltrated area of the lesions in Group 1 (NIPAR) compared to Group 2 (ICON). Statistical analysis revealed a significant difference between the two groups (P< 0.05). Within the limitations of this study, NIPAR allowed for better infiltration of non-cavitated proximal carious lesions when compared to ICON.

Clinical Significance: The combination of infiltration and sealing using non-invasive proximal adhesive restoration (NIPAR) offers a suitable non-invasive treatment option for non-cavitated proximal lesions combining the advantages of sealing and infiltration.