Optimal asymmetric thread for orthodontic microimplants: Laboratory and clinical evaluation

Abstract

The better performances of the experimental microimplant, under both laboratory and clinical conditions (although statistically insignificant in the latter), demonstrate the superiority of the new asymmetric thread.

Surface characteristics and mechanical behavior of retrieved orthodontic microimplants

“…Motoyoshi et al (2006) recommended limiting MIT to the range of 5 to 10 Ncm for a high success rate for 1.6-mm diameter and 8-mm long mini-implants. Considering that MIT is proportional to the length and diameter of the microimplant (Lim et al, 2008), the recommended MIT range could be smaller for the small microimplant tested in this study (1.3-mm diameter) (Alrbata et al, 2015). In this study, the MIT of retrieved microimplants increased to some extent during reinsertion, and the increase was more significant in RMIP than RMIA.…”

“…It seemed not to have a significant influence on the mechanical behavior of microimplants. Alrbata et al (2015) compared the mechanical behavior of microimplants with the same thread design but different tip lengths (1.00 mm vs. 1.25 mm), and found that the mean MIT was not significantly different between the two groups but the insertion time was shorter in the 1.25 mm group. Although it is uncertain that wearing of tip and thread edges have a great effect on mechanical behavior of the retrieved microimplants, we can speculate that the mechanical behavior might be changed to some extent with the cumulative effect of the worn tip and thread edges and the subsequent reduction of their penetration and cutting capabilities.…”

“…the largest value of torque recorded during the rotation process of the microimplant insertion in torsional shear (ASTM, 2013). Insertion time can reflect cutting and penetrating capabilities (Chung et al, 2014;Alrbata et al, 2015). Removal torque value is an indirect measurement of bone-implant contact or clinical osseointegration.…”

Evaluation of primary stability of innovated orthodontic miniscrew system (STS): An ex-vivo study

“…The primary stability of miniscrews is mostly supported by mechanical retention between bone and miniscrew surface ( 7 , 8 ). Primary stability is influenced by factors such as overloading ( 5 ), bone density ( 6 , 9 - 11 ), cortical bone thickness ( 12 ), screw design ( 13 , 14 ) and root proximity ( 15 ).…”

“…The force used to insert the implant is called insertion torque ( 17 ), insertion torque is related to bone tissue, cortical bone thickness and bone density. Adequate insertion torque is an indicator of mini implant stability ( 14 ). It should be as high to ensure stability and as low enough to prevent overcompression of the bone.…”