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Updated: Nov 19, 2025

An Improved Mechanical Testing Method to Assess Bone-implant Anchorage
Published on: February 10, 2014
Evaluation of stability of three different mini-implants, based on thread shape factor and numerical analysis of
Safiya Sana1, Rekha Reddy1, Ashok Kumar Talapaneni1
1Al-Badar Rural Dental College & Hospital, Department of Orthodontics & Dentofacial Orthopaedics (Gulbarga/KA, India).
Objectives:
Assess the stability of three different mini-implants, based on thread shape factor (TSF), and evaluate stresses at the mini-implant site and surrounding cortical bone on application of retraction force, at two different insertion angles.
Methods:
Mini-implants of three different diameters (M1 - Orthoimplant, 1.8mm), (M2 - Tomas, 1.6mm) and (M3 - Vector TAS, 1.4mm) and length of 8mm were used. Using scanning electronic microscopy, the mean thread depth, pitch and relationship between the two (TSF) were calculated. The mini-implants were loaded into a synthetic bone block and the pull-out strength was tested. One way ANOVA and Tukey post-hoc tests were used to compare the pull-out strength of mini-implants. P values < 0.05 were considered statistically significant. Finite element models (FEM) were constructed with insertion angulation at 90° and 60°, with retraction force of 150 g. The results were analyzed using ANSYS software.
Results:
Statistically significant difference was found among all the three mini-implants for thread depth and pitch (< 0.001). Statistically significant higher pull-out force value was seen for Orthoimplant. The stress distribution level in mini-implant and surrounding bone was observed to be smaller for Orthoimplant.
Conclusion:
Orthoimplant mini-implants have more favorable geometric characteristics among the three types, and less stress with 90°angulation.
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