Chanikarn Srinok. Association between insertion torque and the success of mini-screws used as orthodontic anchorage . Master's Degree(Orthodontics). Mahidol University. : Mahidol University, 2008.
Association between insertion torque and the success of mini-screws used as orthodontic anchorage
Abstract:
The purposes of this study were - (1) to investigate the association of the
insertion torque and the success of mini-screws used as orthodontic anchorage., (2) to
determine the optimal insertion torque range., (3) to examine the success rate of miniscrews.,
and (4) to identify other factors associated with the success of the miniscrews.
Forty two mini-screws (1.4 x 7 mm) were placed in 25 patients (6 male, 15
female; mean age 25.6 years). The digital torque gauge was used to measure the
maximum insertion torque. Mini-screws were loaded immediately after insertion with
a force of 100-150 g. Each patient received a questionnaire with a visual analogue
scale (VAS) concerning the pain caused by the surgical procedure. The result
implicated that there was no statistically significant association between the insertion
torque and the success of mini-screws. The optimal insertion torque could not be
defined but there was a tendency that the mini-screws with an insertion torque in the
range of 4-8 Ncm showed a higher success rate than those of insertion torque < 4
Ncm ( P = 0.096). The 3-month success rate of mini-screws was 73.8%. There was no
statistically significant association between the clinical variables of host factors (age,
gender, jaw, side, bone density, tightness when driving the mini-screws, skeletal and
dental relationship), procedure factors (operator, method of insertion, and path of
insertion) and success rate. The pain caused by mini-screw insertion is about 1-1.7 on
the 10-point and the pain is reduced to near zero 1 week after insertion