1 DDS, MS Assoc. Prof. Dept. of Orthodontics, Dental School, Shiraz University of Medical Sciences, Shiraz, Iran

2 Orthodontist

3 DDS, MS Assoc. Prof. Dept. of Restorative Dentistry, Dental School, Shiraz University of Medical Sciences, Shiraz, Iran



Background and aim: Different adhesives have been used for bonding orthodontic brackets to teeth. The aim of this study was to evaluate the possibility of using Core Max II in bracket bonding by comparing it's shear bond strength with the two commonly used orthodontic adhesives; Transbond XT and Unite.
Subjects and Methods: In this interventional study, 105 human premolars were divided into 3 groups of 35 each. After etching with 37% phosphoric acid, Dyna-Lock stainless steel brackets (3M Unitek, Monrovia, CA) with the average base surface area of 12.09 mm2 were bonded with three different adhesives: Core Max II (Sankin, Tokyo, Japan) Transbond XT (3M Unitek) and Unite (3M Unitek). The shear bond strength of 3 groups were measured by a universal testing machine (lnstron 3401, Canton, Mass) with cross- head speed of 0.5 mm/min. Adhesive Remnant Index (ARI) was determined under 10x magnification. For data analysis, SPSS statistical package was used.
Results: Mean shear bond strength of Core Max 11 (17.24± 3.2 MPa) was significantly higher than Transbond XT (15.44 ± 2.2 MPa) (P=0.009) but had not statistically difference with Unite (17.16 ± 3.7 MPa) (P=0.93). Evaluation of ARI indicated that 83% of Core Max II samples had score 0 or 1 and 17% had score 2 or 3. These percentages were 66% and 34% for Transbond XT and 77% and 23% for Unite, respectively.
Conclusion: In this study, it was concluded that: 1) Core Max II had a shear bond strength higher that Transbond XT and equal to Unite. 2) ARI of Core Max II showed a higher frequency of score 0 and 1, which indicated that after debonding, most of the adhesive remains on the bracket base. 3) Core Max II has the potential of being a good orthodontic adhesive. (IJO 2006; 1: 42 - 47)