Comparison of friction and shear bond strength characteristics between tooth colored brackets and metallic bracekts in orthodontic treatment

Objectives: The aim of this study is to compare the characteristics of esthetic brackets and stainless steel braces used recently in orthodontic treatment. Methods: Articles were searched the PubMed databases from 2006 up to March 2017 with the key words or combinations: esthetic bracket, polycarbonate bracket, ceramic bracket. Data from the included studies were listed, including study name and author, year of publication, participations (plastic and ceramic brackets), intervention (tested mechanical and biomechanical properties) and outcome. Risk of Bias was included in the extraction procedure with ROB tool. Results: 20 studies were included in this systematic review and data for friction forces in 11 studies and date for shear bond strength from 3 studies were extracted for narrative analysis. Frictional forces of glass fiber or filler reinforced plastic brackets is significant higher than that of metallic brackets, however, brackets with metal slots created remarkable lower frictional force compared to stainless steel brackets. Polycrystalline brackets created significant higher frictional forces than stainless steel brackets, monocrystalline, metal slot reinforced and self ligating ceramic brackets. All designs of ceramic brackets have significant higher shear bond strength compared to stainless steel brackets, except for polycrystalline brackets with polymer mesh base. Bond strength of plastic brackets was significant lower than that of metallic brackets. Conclusions: This study is an overview about the properties of all esthetic brackets compared to traditional metallic ones, especially the frictional force and shear bond strength