Maximum Clinical Insertion Torque and Its Association With the Success Rate of Orthodontic Miniscrews

Overview

Orthodontic miniscrews provide temporary skeletal anchorage but are lost prematurely in a proportion of cases despite correct placement. The insertion torque generated when a miniscrew is seated has been proposed as a marker of primary stability, but its relationship with clinical success remains uncertain and the existing evidence is limited. This prospective observational cohort study evaluated orthodontic miniscrews placed for skeletal anchorage during routine fixed orthodontic treatment at the postgraduate orthodontic clinic of Universidad de los Andes, Santiago, Chile. The primary objective was to determine whether the maximum clinical insertion torque measured at placement is associated with miniscrew success. Maximum insertion torque and patient-, device-, site-, and treatment-related characteristics were recorded, and each miniscrew was followed until elective removal or failure.

Orthodontic miniscrews are widely used to provide temporary skeletal anchorage, yet the prognostic value of the insertion torque generated at placement remains uncertain. In this single-center prospective cohort, miniscrews placed for skeletal anchorage during routine fixed orthodontic treatment were followed under real-world clinical conditions. All miniscrews were placed by a single experienced operator following a standardized clinical protocol. Maximum clinical insertion torque was recorded at final seating using a calibrated manual disk-type torque wrench as the reference measurement, with a digital torque meter used for corroboration at sites with difficult access or when values exceeded the manual gauge range. Each miniscrew was monitored at routine orthodontic visits from placement until elective removal or failure, and its observation time was recorded. The study evaluates the association between maximum insertion torque and miniscrew outcome, accounting for the clustering of multiple miniscrews within patients, and describes insertion torque across anatomical insertion sites.

Conditions