Title: Evaluation of shear bond strength of ceramic brackets bonded to three different types of porcelain crowns: In vitro study
Authors: Dr Vikas V, Dr Bhagyashri B, Dr Sangamesh B, Dr Srinivas, Dr Neelkanth P, Dr Sameer
DOI: https://dx.doi.org/10.18535/jmscr/v8i4.59
Abstract
Introduction
Smile aesthetics have influence on facial attractiveness and it strongly improves the personality and develops social interaction. So, every orthodontic patient has more concern to get the beautiful smiles at the end of orthodontic treatment but is also equally concerned with appearance while undergoing treatment. Many attempts have been made by manufacturers to meet this demand. This leads to innovative progress in orthodontic bracket systems, which resulted in the introduction of the smaller metal brackets, development of lingual or invisible aligners, making plastic brackets and at lastly translucent ceramic brackets. In mid 1980s ceramic orthodontic brackets were introduced in orthodontic world, as a more esthetically pleasing than the stainless steel brackets1,2. In adults, clinicians often bond orthodontic brackets to teeth that have different types of restorations such as porcelain crowns or laminates whereas adults prefer aesthetic looks even during the treatment, hence clinicians often bond ceramic brackets instead of metal brackets3. Porcelain surface do not bond readily with orthodontic brackets, the surface characteristics of porcelain are altered through certain approaches before bonding the brackets. Some of these are applying silane couplers, etching with hydrofluoric acid, or sandblasting the porcelain surface. Phosphoric acid solution is also used to enhance bond strength of the porcelain surface but it is not as efficient as hydrofluoric acid4.The bond failure at the bracket-adhesive interface is consider being safer than enamel- adhesive interface that results in increased incidence of enamel fractures. Artun J and Bergland S, 1984 modified the ARI which is one such index that evaluate the site of bond failure, that will be helpful in accessing the versatility of different ceramic brackets.5
Bond strengths between 6 and 8 MPa are clinically sufficient for successful bonding of brackets to enamel. Numerous studies have reported the effect of acid etching, etching duration, acid concentration, bond strength of different ceramics, but only few studies have attempted to correlate altered surface roughness after the surface treatment by etching, sand blasting & application of silane coupling agent. Hence, the present study has been advocated for evaluation of the shear bond strength of ceramic brackets bonded to three types of porcelain crowns and assessing their adhesive remnant index with surface roughness of crowns6,7.
