teeth having crack lines, heavy caries, large restorations, hypoplasia,
hypocalcification and nonvital tooth (55) and by reducing the bond strength of ceramic brackets by adding mechanical retention (19,37) by reducing chemical retention (76) by adding a metal mesh at the base of the bracket, by reducing the base area of the brackets, by using weaker resins (76,77) by adding extra plasticizer to the resin (78), by modifying the thickness of adhesive used (79), by modifying the etching time and/or concentration of etching acid ([H.