Do universal adhesives applied with different modes affect remineralized enamel surfaces? A SEM study.

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Adhesive Dentistry

Background:

• White spot lesions (WSLs) are early demineralized enamel defects.
• Restoring WSLs often involves adhesive dentistry techniques.
• The bond strength of universal adhesives to remineralized enamel is critical for restoration longevity.

Purpose of the Study:

• To evaluate the effect of universal adhesive application modes on enamel shear bond strength after remineralization of WSLs.
• To analyze changes in the remineralized enamel surface's calcium/phosphorus (Ca/P) ratio using SEM/EDX.
• To compare the performance of different universal adhesives and application modes (total-etch vs. self-etch) on various enamel states.

Main Methods:

• 144 bovine enamel samples for shear bond strength testing and 120 for Ca/P ratio analysis.
• Demineralization and remineralization cycles were applied, with measurements using DIAGNOdent Pen.
• Two universal adhesives (G-Premio Bond, Clearfil S3 Universal Bond) were applied in total-etch and self-etch modes to intact, demineralized, and remineralized enamel, followed by resin composite placement.

Main Results:

• Statistically significant differences were observed in bond strength and Ca/P ratios across universal adhesives, application modes, and enamel surface types.
• Highest bond strength was achieved on sound enamel using the total-etch mode for both adhesives.
• Remineralization with Remin Pro significantly increased bond strength on WSLs, approaching levels seen on intact enamel. Universal adhesives altered the Ca/P ratio on remineralized surfaces.

Conclusions:

• Remineralizing white spot lesions prior to adhesive application is recommended to enhance bond strength.
• Bond strength to remineralized enamel, especially when treated with Remin Pro, is comparable to intact enamel.
• The choice of universal adhesive and application mode (self-etch often preferred for remineralized enamel) influences bond strength, and orthophosphoric acid use requires caution.