Evaluation of Resin Penetration Depth in Enamel Surface for Orthodontic Bonding Exposed to Five Types of Enamel...

To evaluate the enamel surface depth of resin penetration for orthodontic bonding when exposed to five types of enamel conditioning methods using scanning electron microscope.

The sample comprised of 25 human extracted premolar teeth for orthodontic reasons. The samples are divided into 5 groups with each 5 teeth based on the enamel conditioning methods such as group A with 37% Phosphoric acid, group B with 10% Polyacrylic acid, group C with Self etch primer, group D with Laser etching and group E with air abrasion etching. All the samples in each group are bonded with metal brackets using Transbond XT Adhesive. After bonding, the teeth are sectioned mesiodistally using hard-tissue microtome and observed under scanning electron microscope at 500x and 3000x for the calculation of depth of resin penetration.

The teeth etched with 37%phosphoric acid exhibited significantly greater depth of resin penetration (15.1µm) than do self-etch and polyacrylic acid. Laser etching has comparable penetration depth with that of acid etching. Air abrasion has got the least penetration of all groups.

Comparing the enamel treated with these conditioning methods, the penetration of resin material into enamel are greater when it is treated with 37% Phosphoric acid than self-etch or laser etching.