Evaluation of friction of conventional and metal-insert ceramic brackets in various bracket-archwire combinations

Evaluation of frictional forces between ceramic brackets and archwires of different alloys compared with metal brackets

“…1,4,3,27 Nonetheless, in this study, friction values for ceramic brackets with metal slots (Clarity) were similar to those of conventional ceramic brackets (InVu). This could be because of several factors.…”

“…Studies that evaluate the friction produced by different brackets and wires diverge a great deal, because of the variety of methodologies, 3,4 variety of alloys tested from different companies, 16 different bracket and wire combinations, medium for testing (dry environment, saliva or substitutes), 17 and whether simulating second-or third-order angulations. 1,4,7,15 This makes it difficult to compare results.…”

“…20,21 With respect to wire angulation, the results of this study are in agreement with those of other studies, in which similar or somewhat lower frictional forces were observed for SS wires compared with Ni-Ti wires, when no second order angulation was present. 3,4,18,20,22 When angulations are incorporated, frictional forces increase proportionately, as does the gap between alloys, with the SS wires producing the highest values. 23,24 Despite the rougher surfaces of Ni-Ti wires, they produce lower friction, because other properties, such as hardness and deflection of the wire, help create softer contacts and decrease binding.…”

“…6 The present study shows results similar to those of other investigators, who point to SS brackets as the ones producing the lowest frictional forces. 1,3,20,27 This is attributable to the physical properties of the metal, which provide a low coefficient of friction and allow a good surface finish. For this reason, one of the methods used by manufacturers to improve friction levels in ceramic brackets is to incorporate metal slots.…”

“…2 Despite manufacturers' efforts to improve their qualities by incorporating metal slots, dulling the slot edges, and glazing their surfaces, the physical properties of ceramic brackets are still inferior. 3,4 Up to 60% of the force applied for dental movement can be lost as the result of ceramic bracket resistance to sliding, [5][6][7][8] leading to a longer treatment period.…”