• Journal of Dental Rehabilitation and Applied Science
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• v.23 no.4
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• pp.337-358
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• 2007

Purpose This study was performed to evaluate the stability of dual thread implant using resonance frequency analysis in human. Materials and methods Fifty-five patients(32 males and 23 females) with a mean age of 50 years and 1 month who were treated during March, 2005 to July, 2007 in Pusan National University hospital. Totally 145 dual thread Implants were installed and initial stability was measured by Osstell $Mentor^{TM}$. After 3-6 Months, secondary stability was measured at the time of second surgery or before prosthetic treatment. Results At the time of 1st surgery, average ISQ value was $75.12{\pm}12.06$. Only 1 implant was failed during the healing period. Before prosthetic treatment, ISQ values were measured and its mean value was $80.94{\pm}6.12$. Conclusion These results suggest that the increased stability of the implant verifies the clinical relevance of double thread implant.

• The korean journal of orthodontics
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• v.44 no.4
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• pp.177-183
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• 2014

Objective: To determine the unique contribution of geometrical design characteristics of orthodontic mini-implants on maximum insertion torque while controlling for the influence of cortical bone thickness. Methods: Total number of 100 cylindrical orthodontic mini-implants was used. Geometrical design characteristics of ten specimens of ten types of cylindrical self-drilling orthodontic mini-implants (Ortho Easy$^{(R)}$, Aarhus, and Dual Top$^{TM}$) with diameters ranging from 1.4 to 2.0 mm and lengths of 6 and 8 mm were measured. Maximum insertion torque was recorded during manual insertion of mini-implants into bone samples. Cortical bone thickness was measured. Retrieved data were analyzed in a multiple regression model. Results: Significant predictors for higher maximum insertion torque included larger outer diameter of implant, higher lead angle of thread, and thicker cortical bone, and their unique contribution to maximum insertion torque was 12.3%, 10.7%, and 24.7%, respectively. Conclusions: The maximum insertion torque values are best controlled by choosing an implant diameter and lead angle according to the assessed thickness of cortical bone.

• The korean journal of orthodontics
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• v.36 no.1 s.114
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• pp.55-62
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• 2006

Orthodontic mini-implants, despite its usefulness as anchorage, have some limits such as loosening. Therefore, various shapes and lengths have been studied. The aim of this study is to analyze the shape and length of mini-implants mechanically. The shapes of mini-implants (1.6 mm, Dual Top, Jeil Medical Co., Seoul, Korea) were cylindrical and taper. The lengths of mini-implants were 6 mm and 8 mm. The tested groups were 5 groups (cylindrical 6 mm, cylindrical 8 mm, taper 6 mm, taper 8 mm and taper 8 mm modified whose thread is reduced from the middle to upper part). All were inserted and removed on the polyurethane foam with the torque measured. During insertion and removal, the taper shape needed higher torque than the cylindrical shape, and the 8 mm length than the 6 mm length (p<0.001). The taper 6mm group showed superior insertion torque (p<0.001) and similar removal torque to the cylindrical 8 mm group. The taper 8 mm modified group with gradually reduced threads, showed continuous high removal torque after the peak. The initial mechanical stability can be provided by the tapered shape and also, affected by length and thread design.