engleski

Manual vs. machine implantation of orthodontic miniscrews – influence on maximal insertion torque

OBJECTIVES: The aim was to explore the influence of implantation mode (manual vs. machine) on maximal insertion torque (MIT) of orthodontic miniscrews controlling for cortical thickness, implant diameter and length as covariates. MATERIALS AND METHODS: One hundred and twenty cylindrical self-drilling miniscrews Dual Top (Jeil Medical Corp., Seul, Korea) of thread diameter 1.4, 1.6 and 2.0 mm, and length 6 and 8 mm were implanted in perpendicular direction into the swine ribs bone blocks (2x1 cm, cortical thickness in range 0.8 – 2.4 mm). Miniscrews were inserted independently by manual and machine screwdriver of constant speed, without prediriling a guiding hole. MIT and cortical bone thickness were measured. Multiple linear regression was used in statistical analysis. RESULTS: Manual implantation is significantly associated with higher MIT (p<0.001) but producing low effect size (12.3%). Other significant predictors of MIT are thicker cortical bone (p<0.001), wider thread diameter (p<0.001) and higher implant length (p<0.001) producing the effect sizes of 24.5%, 18.4% and 4.4%, respectively. CONCLUSION: Manual implantation produces higher MIT than machine implantation, but cortical bone thickness and thread diameter have higher influence on MIT than implantation mode and implant thread length.

miniscrew ; orthodontics ; torque

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