The effect of multiple processing and re-use on orthodontic mini-screw torque values

Area of Science:

• Orthodontics
• Biomaterials Engineering
• Dental Implantology

Background:

• Orthodontic mini-screws are crucial for treatment but costly.
• Reusing mini-screws could lower costs and increase their application.
• Assessing the mechanical integrity of reprocessed mini-screws is essential.

Purpose of the Study:

• To evaluate the effects of reprocessing and reuse on titanium mini-screws.
• To determine if repeated sterilization impacts insertion, removal, and fracture torque.
• To assess the feasibility of cost-effective mini-screw reuse in orthodontics.

Main Methods:

• Twenty 1.6-mm × 8-mm titanium mini-screws were used.
• Control group: initial fracture torque (FT) assessed.
• Test group: screws underwent 5 cycles of insertion, cleaning, chemical processing, and autoclaving before FT assessment.
• Maximum insertion and removal torque were compared between groups.

Main Results:

• No significant difference in fracture torque (FT) was found between new and five-time-used mini-screws.
• Maximum insertion torque showed minor variations but no consistent negative trend with reuse.
• Maximum removal torque showed some variability, with the second removal torque being significantly higher than others (except the first).

Conclusions:

• Five-time reuse, including cleaning, processing, and steam sterilization, did not significantly compromise mini-screw mechanical properties.
• Reprocessing and sterilization appear safe for titanium mini-screws regarding torque values.
• Findings suggest potential for cost savings and wider mini-screw utilization in orthodontics.