[Enamel wear from ceramic and stainless steel orthodontic brackets]

The purpose of this investigation was to examine the potential enamel wear upon contact with ceramic and stainless steel orthodontic brackets of the same company into an artificial mouth, which is a simulated oral environment. Two groups of ten lower premolars were bonded with ceramic and stainless steel brackets. The same number of upper premolars were used and each upper premolar was brought in contact with the opposing bracket and subjected to a lateral type of movement, like a mastication movement, by the artificial mouth. A constant load of approximately two pounds was used for the masticatory force, the rate of chewing was one cycle per second and the teeth were subjected to 2.5 and 10 masticatory cycles. The before and after occlusal surfaces of the upper premolars were compared using a computerized profiling system and the enamel volume loss was calculated. Qualitative changes, such as rate of enamel wear, were examined visually using SEM and computer graphics. Abrasion scores (mean +/- SD) in mm3 were 0.0142 +/- 0.020 for the metal and 0.2433 +/- 0.150 for the ceramic brackets and were significantly different at p less than 0.05. Ceramic brackets caused significantly greater enamel abrasion than stainless steel brackets.