Bonding to ground versus unground enamel in fluorosed teeth

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Enamel Surface Treatment

Background:

• Fluorosed enamel exhibits altered surface properties, potentially compromising adhesive bonding.
• Conventional surface preparation methods may be insufficient for optimal resin adhesion to fluorosed enamel.

Purpose of the Study:

• To evaluate the impact of enamel grinding on the bond strength of self-etch and etch-and-rinse dental adhesives to fluorosed enamel.
• To compare the bonding effectiveness to ground versus unground fluorosed enamel.

Main Methods:

• Teeth were classified by fluorosis severity using the Thylstrup and Fejerskov index (TFI).
• Enamel surfaces were either ground (0.3mm depth) or left unprepared.
• A two-step self-etch (Clearfil Protect Bond) and a three-step etch-and-rinse (Optibond FL) adhesive were applied.
• Micro-tensile bond strength (microTBS) was measured on prepared specimens.

Main Results:

• Grinding significantly increased microTBS for both adhesives on fluorosed enamel (p<0.0001 for self-etch, p<0.05 for etch-and-rinse).
• Self-etch adhesive showed significantly lower bond strength to unground fluorosed enamel compared to ground fluorosed enamel.
• Control (non-fluorosed) enamel showed improved bonding with the self-etch adhesive after grinding.

Conclusions:

• Enamel preparation by grinding enhances resin-enamel bond strength in fluorosed teeth.
• Self-etch adhesive performance is notably reduced on unground fluorosed enamel compared to healthy enamel.