The Study Of The Bonding Effect Of Two Fluor-releasing Adhesive Systems

Objective The purpose of this study is to evaluate the bonding effect of brackets with two methods of topical fluoridation(S elf-etching orthodontic bonding and fluoridation after acid etching on enamel)Methods This study consists of two parts: laboratory experiment and clinical research . Laboratory experiments: Thirty freshly extracted premolars were randomly divided into three groups:Group A(Self-etching primer +Transbond XT) Group B(fluor protector application after acid etching +Jingjin adhesive )and Group C(jJingjin adhesive was used as control group ). The shear bond strength and adhesive remnant index were determined after 24 hours of water bath at 37 C. Stainless steel brackets were bonded in each test group . After bonding ,all samples were stored in distilled water at room temperature for 24 hours , then tested for shear bond strength and adhesive remnant index . Clinical experiment: 39 subjects (10-15 years old )with full-fixed appliances and a range of malocclusions covering Angle Class I , Class II and Class III with crowding . A total of 540 teeth were tested, 180 in Self-etching bonding system, 180 in fluoridation after acid etching bonding system and the remaining 180 in jingjin adhesives. Bond failure frequencies were recorded for 12 months ,and chi-square statistical test was carried out comparing the failure rate of the three adhesive systems.Results In laboratory experiment there were statistically significant differences among the three groups in both shear bond strength and ARI scores . The Self-etching group has the highest shear bond strength and ARI scores ,and the post-etching fluoridation group has the lowest shear bond strength and comparatively lower ARI scores .But the shear bond strength of all groups reached the clinical requirement. .In clinical study, there was no significant differences in failure rates of direct bonded orthodontic brackets cemented with the three adhesive systems.Conclusion Both self-etching system and post-etching fluoridation may be availableto clinical use .