Adhesive systems for CAD-CAM customised lingual orthodontic brackets: Which one is better?

AIM:ERYag laser have been described as a more conservative alternative to conventional acid-etching enamel conditioning technique when bonding conventional metallic orthodontic brackets. Since the use of aestethic orthodontic brackets is constantly increasing, the purpose of the present report has been to test laser conditioning with different aesthetic brackets. METHODS: Study design: five different aesthetic brackets (microfilled copolymer, glass fiber, sapphire, polyoxymethylene and sintered ceramic) were tested for shear bond strenght and Adhesive Remnant Index scores using two different enamel conditioning techniques (acid etching and ERYag laser application). Two hundred bovine incisors were extracted, cleaned and embedded in resin. Specimens were then divided into 10 groups with random tables. Half of specimens were conditioned with conventional orthophosphoric acid gel, the other half with ERYag laser. Different aesthetic brackets (microfilled copolymer, glass fiber, sapphire, polyoxymethylene and sintered ceramic) were then bonded to the teeth. Subsrquently all groups were tested in shear mode with a Universal Testing Machine. Shear bond strenght values and adhesive remnant index scores were recorded. Statistical analysis was performed. RESULTS: when considering conventional acid etching technique, sapphire, polyoxymethylene and sintered ceramic brackets exhibited the highest SBS values. Lowest values were reported for microfilled copolymer and glass fiber appliances.A significant decrease in SBS values after laser conditioning was reported for sapphire, polyoxymethylene and sintered ceramic, whereas no significant difference was reported for microfilled copolymer and glass fiber brackets. Significant differences in ARI scores were also reported.