Comparison Between Stainless Steel and Polyetheretherketone (PEEK) Temporary Anchorage Devices in Orthodontics - A Comparative Study.

Abstract

Background: Mini-implants are crucial in orthodontics for absolute anchorage, allowing precise dental movements without affecting adjacent structures. Exploring alternative materials with proven biocompatibility and potential for improved clinical performance is essential. This study compares the mechanical resistance of polyetheretherketone (PEEK) and stainless steel mini-implants to evaluate PEEK's feasibility as an alternative.

Objectives: To compare PEEK and stainless steel for orthodontic mini-implants, focusing on maximum load resistance and suitability for temporary anchorage.

Materials and methods: Two groups of 12 mini-implants (2 mm × 8 mm) were tested: milled PEEK and stainless steel (TD Orthodontics©, Nuevo León, Mexico). Both mini-implants were inserted into porcine mandibles, sectioned placed in acrylic bases and subjected to maximum load tests using a universal testing machine. Data normality was assessed with the Shapiro-Wilk test and variances with Levene's test. Comparisons were performed using Welch's t -test (α = 0.05), with effect sizes (Hedges' g) and 95% confidence intervals reported.

Results: Stainless steel mini-implants showed a mean maximum load of 255.77 N whereas PEEK averaged 57.14 N after outlier adjustment. Welch's t -test confirmed a significant difference between groups ( P < 0.001) with a large effect size (Hedges' g = 2.31). Statistically significant differences were observed between groups, with a mean difference of 198.6 N (95% CI 126.3-271.0).

Conclusion: Although stainless steel exhibited greater load resistance, PEEK mini-implants exceeded clinically relevant orthodontic forces (50-400 g), supporting their potential as temporary anchorage devices. Further in vivo and clinical studies are needed to confirm long-term performance.