Abstract:

BACKGROUND: With the development of the thermoplastic technology, the thermoplastic materials modified appliance becomes being used in orthodontics.
OBJECTIVE: To observe the differences of bending mechanical properties among the thermoplastic materials with different thicknesses.
METHODS: The experiment was performed at room temperature of 25 ℃, and the thermoplastic material Simona with thickness of 1.0 mm, 1.2 mm, 1.5 mm, and 2.0 mm were involved, 10 pieces of each type. The Simona were tested by universal testing machine before treatment (area was 40 mm×25 mm) and after formation with different rectangle moulds (volume was 50 mm×  10 mm×5 mm) in order to compare their bending mechanical properties.
RESULTS ANS CONCLUSION: The modulus, yield strength and the maximum stress of the Simona 2.0 mm were the highest with different treatment (P < 0.05), and there was no fracture. The materials with different thicknesses and shapes have different mechanical properties. The Simona 2.0 mm is suitable for functional appliance base on its high mechanical properties.