New/Modern Adhesive Systems in Orthodontics

The success of therapy with fixed orthodontic devices depends on several factors. Particularly important for its successful realisation, among other things, is adequate strength of adhesion of the brackets onto the surface of the tooth, and in this connection, their occasional debonding. Changing the debonded bracket with a new one often prolongs therapy and causes financial loss to the clinician due to the used material and time (1). Various investigations have indicated that bond strength of 2.8 Mpa10 Mpa is suitable for clinical practice (2,3,4). However, the bond strength can be effected by different factors. Thus, Sharma-Sayal et al (5) point out that the appearance of the base of the bracket has a significant effect on bonding. Olsen et al (6) investigated the effect of enamel preparation prior to placing the bracket and determined that air abrasion compared with classical etching of the tooth surface with 37% phosphoric acid weakens the bond between the tooth and bracket. Consequently, they do not recommend this method in everyday clinical practice. In their investigation the duration of etching with acid did not appear to be an important factor. Namely, it was determined that it is clinically sufficient to etch for only 15 seconds, although clinicians are usually recommended 20 to 30 seconds. They also determined that even after 60 seconds of etching the bond between tooth and bracket is not significantly better (7, 8). Hobson et al (9) investigated the influence of different groups of teeth on this parameter. They started from the fact that the density of aprismatic enamel is different on different teeth, and showed that bond strength between the bracket and tooth is greatest on the first lower molar, and weakest on the first upper molar. Different materials are available on the market, which are used for bonding brackets onto the surface of enamel. With the development of the etching technique new orthodontic devices with brackets, which are fixed with different composite resNew/Modern Adhesive Systems in Orthodontics Suzana Varga Mladen Šlaj