Effect of dual pitch mini-implant design and diameter of an orthodontic mini-implant on the insertion and removal torque.
- Author:
Jong Wan KIM
1
;
Il Sik CHO
;
Shin Jae LEE
;
Tae Woo KIM
;
Young Il CHANG
Author Information
1. Department of Dentistry, Seoul National University Bundang Hospital, Korea.
- Publication Type:Original Article
- Keywords:
Orthodontic mini-implant;
Stability;
Dual pitch;
Diameter
- MeSH:
Polyurethanes;
Torque*
- From:Korean Journal of Orthodontics
2006;36(4):275-283
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
OBJECTIVE: Small orthodontic mini-implants are useful as anchorage. However they have some weaknesses such as loosening. This study was carried out to analyze the mechanical effects of the dual pitch and diameter on the insertion and removal torque of mini-implants. METHODS: The threads of mini-implants were mono and dual pitch. The diameters of mini-implants were 1.4 mm and 1.6 mm. Four groups were tested (mono 1.4 mm, mono 1.6 mm, dual 1.4 mm and dual 1.6 mm). All were inserted and removed on polyurethane foam with the torques being measured. RESULTS: The maximum torque of the dual pitch groups was higher than the mono pitch groups during removal but lower during insertion. The maximum torque of the 1.6 mm diameter groups was higher than the 1.4 mm diameter groups during insertion and removal. The dual pitch 1.4 mm group showed the lowest insertion torque but had similar or superior levels of removal torque to that of the mono pitch 1.6 mm group. CONCLUSIONS: The dual pitch especially showed a continuous high removal torque after the peak. Despite the small diameter, the dual pitch might improve the initial mechanical stability.
