The impact of testosterone suppression and supraphysiological doses on bone and root quality during induced orthodontic tooth movement in animals at puberty.

• Grant number: 23/07911-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2023
• End date: November 01, 2024
• Field of knowledge: Health Sciences - Dentistry - Orthodontics
• Principal Investigator: Mírian Aiko Nakane Matsumoto
• Grantee: Leticia Cassaro
• Host Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

During puberty, the increase in hormonal levels can affect the response of adolescent patients to orthodontic treatment. However, little is known about the influence of testosterone on Orthodontic Tooth Movement (OTM). The aim of this study is to evaluate how testosterone deficiency, replacement, and excessive (supraphysiological) doses can impact bone and root quality during OTM in an animal model during puberty. 23-day-old Wistar male rats (n=64) will be used, randomly allocated into four experimental groups. Two groups will undergo surgical removal of the testicles (Orchiectomy) to induce testosterone deficiency, and in one of these groups, Testosterone Undecanoate (TU) will be administered for hormonal replacement. The other two groups will undergo a simulated placebo surgery (Sham Surgery), and in one of them, supraphysiological doses of TU will be administered. At 50-day-old, OTM will be induced using a a NiTi closed coil spring on first left molar applying a force of 0.25 N. OTM will be performed only on one side of the maxilla, randomly selected, while the other side will serve as the control group. Euthanasia of the animals will occur after 5 and 10 days of OTM. Bone quality of the maxilla and the volume of root resorption will be evaluated using 3D microtomography. The side of the maxilla that is not subjected to an orthodontic force will also be analyzed using the same methods. The data will be statistically analyzed at a significance level of 0.05. This study has the potential to produce innovative and directly applicable results to orthodontic treatment of teenagers, aiming to investigate the importance of considering hormonal levels by orthodontists when defining treatment strategies.