AIM AND OBJECTIVES: This study aimed to evaluate and compare the biomechanical behavior of titanium and poly-ether-ether-ketone (PEEK) orthodontic mini-screws. The objectives were to assess their performance through four biomechanical tests: maximum insertion torque (MIT), fracture torque (FT), vertical pull-out strength (VPS), and horizontal resistance (HR). MATERIALS AND METHODS: A total of 156 mini-screws (78 titanium, 78 PEEK), equally divided into 1.4 mm and 1.6 mm diameter groups, were inserted into artificial bone blocks under standardized in vitro conditions. Mechanical testing was conducted to evaluate each performance parameter. Data were analyzed using IBM statistical package for the social sciences (SPSS) software via one-way analysis of variance (ANOVA) or the Kruskal–Wallis test, depending on distribution, with a significance level of P 0.05), although overall PEEK screws showed lower MIT values. In FT, VPS, and HR tests, PEEK screws frequently deformed, or fractured under loading, whereas titanium screws demonstrated significantly higher mechanical performance ( P < 0.001). CONCLUSION: Titanium mini-screws outperformed unreinforced PEEK screws across all mechanical tests, demonstrating superior torsional, pull-out, and lateral resistance. Additionally, larger-diameter screws (1.6 mm) showed better mechanical performance than smaller ones (1.4 mm) in both materials.
Al-hamadani et al. (Sun,) studied this question.