Title: Adhesive systems for CAD-CAM customised lingual orthodontic brackets: which one is better?
Abstract: Aim Aesthetic orthodontic treatment demand is constantly increasing also for patients in adolescent age. New orthodontic protocols with CAD-CAM customised bracket bases have been introduced for lingual orthodontic therapy. The aim of the present study was to compare the shear bond strength (SBS) and Adhesive Remnant Index (ARI) scores of customised lingual brackets bonded with different adhesive systems.
Materials and methods Study design: Customised CAD-CAM lingual bracket bases were tested for shear bond strength and adhesive remnant index scores using three different adhesive systems.
Sixty human permanent premolars were extracted for orthodontic reasons and embedded in resin blocks. Customised CAD-CAM lingual bracket bases were prepared and bonded using a pre-mix chemical cure adhesive (Transbond IDB), a chemical cure adhesive system (Maximum Cure) and a dual-cure self-adhesive resin cement (RelyX Unicem 2). All samples were tested in shear mode on a Universal Testing Machine. SBS and ARI scores were calculated. Statistics: Statistical analysis included ANOVA and Tukey tests for SBS and Chi squared for ARI Scores.
Results Dual-cure self-adhesive resin cement showed significantly higher SBS values than pre-mix chemical cure adhesive and chemical cure adhesive system that showed no significant difference between them. No significant differences in ARI Scores were found among various groups.
Conclusions Dual-cure self-adhesive resin cement (RelyX Unicem 2) provides higher SBS values than pre-mix chemical cure adhesive (Transbond IDB) or chemical cure adhesive (Maximum Cure) and can be recommended to obtain higher adhesion performances of CAD-CAM lingual brackets.