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Updated: Mar 11, 2026
An Improved Mechanical Testing Method to Assess Bone-implant Anchorage
Published on: February 10, 2014
Effect of longitudinal flutes on miniscrew implant stability and 3-dimensional bone formation
Peter An V Truong1, Phillip M Campbell2, Elias D Kontogiorgos3
1Private practice, Irvine, Calif.
Introduction:
The purpose of this study was to evaluate the effects of longitudinal flutes on miniscrew implant (MSI) stability and bone healing.
Methods:
Using 11 skeletally mature New Zealand white rabbits, we placed 31 longitudinally fluted and 31 nonfluted, 3-mm-long MSIs in standardized positions in their calvaria and immediately loaded them with 100 g using nickel-titanium coil springs. Insertion torque values were obtained for each MSI placed; removal torque values were obtained for 28 MSIs that had been in place for 6 weeks and 20 MSIs that had been in place for 2 weeks. The bone volume fractions at 6 to 24, 24 to 42, and 42 to 60 μm from the MSI surfaces were evaluated using microcomputed tomography with an isotropic resolution of 6 μm.
Results:
The success rate was 97% for both the fluted and nonfluted MSIs. The difference in insertion torque between the fluted and nonfluted MSIs was not statistically significant (P = 0.930). After 2 weeks, there was no statistically significant (P = 0.702) difference in removal torque between the fluted and nonfluted MSIs. After 6 weeks, removal torque values were significantly (P = 0.008) higher for the fluted (3.42 ± 0.26 N.cm) than the nonfluted (2.49 ± 0.20 N.cm) MSIs. Bone volume fractions of the 6-to-24-, 24-to-42-, and 42-to-60-μm layers were significantly (P <0.05) greater for the nonfluted than the fluted MSIs.
Conclusions:
Loaded 3-mm-long MSIs with and without flutes have high success rates. Longitudinal flutes placed in 3-mm MSIs increased their removal torque by 37% and decreased the amount of bone immediately surrounding them.
