Adhesion Characteristics of Base-Coated Single Crystal Brackets for Orthodontics
Adhesion characteristics of base-coated single crystal brackets for orthodontics were investigated to evaluate the feasibility for the ceramic bracket applications. Sapphire single crystal ingot were machined, abraded and spray-coated with slurries containing 50 wt% of flux and 40µm, 80µm and 150µm of granules. Maximum adhesion to the base surface of the brackets was observed when the size of granule in the slurries was 80µm. It may be due to higher bonding area of adhesive to granule and to base as a result of interlocking structure which has moderate thickness and uniform distribution of granules. The one-way analysis of variance indicated that there were not significant differences in bond strength measurements between the once and twice coating condition in 80µm and 150µm granule groups. But ARI values exhibited large differences between once and twice coating groups and showed different median or ranges. Adhesive remnant of adhesive resin was minimized when the slurry of 80µm granule was coated once. Reduction in adhesive remnant is likely due to the higher bonding of adhesive resin to granules. No teeth and bracket damages were found in any teeth de-bonded by shear force. The base-coated brackets with higher strength (12.9 MPa) and no adhesive remnant were newly proposed for the orthodontics applications.
Marcelo Prado and Cecília Zavaglia
M. H. Lee et al., "Adhesion Characteristics of Base-Coated Single Crystal Brackets for Orthodontics", Key Engineering Materials, Vols. 396-398, pp. 137-140, 2009