Class I cavities restored with the total acid-etching technique.

Class II cavities restored with the total acid-etching technique.

Class I cavities restored with the self-etching technique.

Class II cavities restored with the self-etching technique.

Class I cavities restored with the select-etching technique

the enamel was etched for 30 seconds and the dentin for 15 seconds using 35% phosphoric acid gel (Ultradent). The acid was then rinsed off, and excess moisture was removed with an air spray. To protect the dentin during air blasting, an absorbent paper was held over it using clinical tweezers, ensuring a whitish appearance for the enamel and slightly moist dentin. Excess water on the cotton roll was dried as well. The BeautiBond Xtreme adhesive system was applied without any waiting time, followed by a gentle air spray for 3 seconds and then a strong air blast to ensure solvent evaporation. Finally, the adhesive was light-cured for 5 seconds using a LED photopolymerizer (Gran Valo LED Curing Light, Ultradent).

The anatomic form of the restoration was evaluated according to the modified United States Public Health Service (USPHS) criteria at baseline, six months, and one year. Restorations were classified as Alpha (continuity of the restoration with the existing anatomic form), Bravo (continuity of the restoration with partial degradation but clinically acceptable), or Charlie (continuity of the restoration compromised, requiring replacement).

Marginal adaptation was visually analyzed using an explorer to detect crevices or marginal failures. Classifications included Alpha (no visible evidence of a crevice along the margin), Bravo (visible evidence of a crevice along the margin where the explorer can penetrate or catch), and Charlie (the explorer penetrates the crevice, exposing dentin or base).

Marginal discoloration was assessed by recording any color changes at the interface between the restoration and tooth structure. Restorations were classified as Alpha (no visible discoloration), Bravo (discoloration present but not penetrating along the margin in a pulpal direction), or Charlie (deep discoloration penetrating along the margin toward the pulp).

The presence of secondary caries was clinically and radiographically evaluated throughout the study. Restorations were classified as Alpha (no evidence of secondary caries) or Charlie (evidence of secondary caries around the restoration, requiring replacement).

Color match was evaluated by comparing the restoration to the adjacent tooth structure in terms of color and translucency. Classifications included Alpha (color and translucency compatible with the tooth structure), Bravo (color and translucency mismatch within the acceptable range), and Charlie (color and translucency mismatch outside the acceptable range).