[Study of mechanical properties of shape memory alloy plate for internal fixation of jaws].
Ni-Ti alloy compression mini-plate was developed for rigid bone-fixation in oral surgery. The investigation of the mechanical properties of this plate was performed to obtain basic data for its clinical application. Ni-49.49 Ti (at%) alloy and Ni-49.26 Ti (at%) alloy were used for the specimens. First, transformation temperatures of the alloys were measured to evaluate the effect of heat-treatment temperatures. Secondly, tensile and shape recovery tests were performed on four types of mini-plates, i.e., four-hole regular and long types Ni-49.49 Ti (at%), five-hole regular type Ni-49.49 Ti (at%) and Ni-49.26 Ti (at%). The following results were obtained. 1. Specimens with a heat-treatment at 500 degrees C, for 30 minutes in both compositions showed adequate As points (about 25 degrees C) and Af points (44-50 degrees C) for clinical use. 2. In the tensile and shape recovery tests, the 500 degrees C heat-treated four-hole regular type plate showed better mechanical properties than the 440 degrees C heat-treated one. However, in the four-hole regular type plate without heat-treatment, the shape memory effect was rarely found. 3. The five-hole regular type plate of Ni-49.49 Ti (at%) alloy had the best mechanical properties for clinical application, judging from the amount and the temperature of shape recovery. It is concluded that Ni-Ti shape memory alloy mini-plates should be applied for rigid internal bone-fixation in oral surgery.
Tomitsuka
K
K
First Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tokyo Medical and Dental University.
D000497:Alloys; D001696:Biomechanical Phenomena; D001860:Bone Plates; D005593:Fracture Fixation, Internal; D006358:Hot Temperature; D006801:Humans; D007572:Jaw Fractures / Q000601:surgery*; D009532:Nickel; D013696:Temperature; D014025:Titanium
D000497:Alloys; D009532:Nickel; D014025:Titanium