Abstract: Objective: To evaluate the effect of heat treatment on the forces of buccal multiloop appliance during mouth opening and closing movement. Methods: Stretch-inflection-compression experiment was used to simulate the buccal multiloop appliance during mouth opening and closing movement. Different kinds of heat treatment were discussed in this article. Results: The forces and displacement distance of the buccal multiloop appliance during mouth opening and closing movement increased when it was bended after heat treatment, among which 480℃ was the most obvious. It showed no effect on the displacement distance when it was bended before heat treatment. Conclusion: When making buccal multiloop, the mechanical property of loop can be improved provided the heat temperature was 480℃ and the loop was bended afterwards.

Key words: Buccal multiloop removable appliance , Temperature of heat treatment, Forces of compression and stretch Malocclusion