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Updated: Mar 10, 2026
An Improved Mechanical Testing Method to Assess Bone-implant Anchorage
Published on: February 10, 2014
A Comparison of the Mechanical Measures Used for Assessing Orthodontic Mini-Implant Stability
Yara K Hosein1, S Jeffrey Dixon, Amin S Rizkalla
1*Postdoctoral Fellow, Division of Graduate Orthodontics, Schulich School of Medicine & Dentistry; Bone and Joint Institute; Western University, London, Ontario, Canada. †Distinguished University Professor, Division of Graduate Orthodontics, Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry; Bone and Joint Institute; Western University, London, Ontario, Canada. ‡Professor, Division of Graduate Orthodontics, Schulich School of Medicine & Dentistry; Department of Chemical and Biochemical Engineering, Faculty of Engineering; Bone and Joint Institute; Western University, London, Ontario, Canada. §Assistant Professor, Division of Graduate Orthodontics, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada.
Purpose:
Mechanical loosening remains a common complication associated with mini-implant failure. The purpose of this study was to compare common mechanical measures of mini-implant stability to determine their association and reliability.
Materials And Methods:
Ninety self-drilling orthodontic mini-implants from 6 manufacturers were inserted into artificial bone blocks. Insertion torques (ITs) and Periotest values (PVs) were measured. Subsequently, mini-implants underwent pull-out testing for measures of pull-out load (POL) and screw displacement (ScrD). Stability measurements were compared using one-way ANOVA, associations among them were assessed using correlation analyses, and reliability was evaluated using coefficients of variation (COVs).
Results:
Variations in stability of mini-implants were found, specific to the mechanical measure used for assessment (P < 0.05). The strongest correlations were found between IT and PV (r = -0.68) and between IT and POL (r = 0.66). Overall, PV showed the greatest variability (COV: 11%-100%) compared with IT (≤11%), POL (≤4%), and ScrD (≤19%).
Conclusions:
IT, PV, and POLs only agreed moderately in their assessment of mini-implant stability, and Periotest showed the least reliability in predicting mini-implant stability. As such, independent and interchangeable use of these stability measures should be avoided.
