Microtomographic, histomorphological and histomorphometric evaluation of the bone repair process of the midpalatal suture after the use of the substance Isotretinoin

• Ano de defesa: 2025
• Autor(a) principal: Parreira, Maria Júlia Bento Martins
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Bone regeneration; Isotretinoin; Isotretinoína; Palatal expansion technique; Regeneração óssea; Técnica de expansão palatina
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/25/25149/tde-02122025-160808/

Posterior crossbite is quite prevalent and represents one of the most frequent orthodontic problems that arise during occlusal development. One way to correct it is through rapid maxillary expansion, an orthopedic procedure aimed at improving the transverse dimension of constricted arches. During orthodontic treatment, it is possible that the patient may be using medications that influence bone formation in the expansion area, and knowing which medications these are is crucial to prevent relapse and ensure the stability of the results. Among the medications frequently used during the period that coincides with orthodontic treatment, Isotretinoin stands out. In Article 1, the literature review aimed to analyze the systemic administration of Isotretinoin and its effects on bone tissue. For this purpose, studies that demonstrated effects of Isotretinoin on bone metabolism, bone mineral density, bone formation and resorption, as well as any possible alterations in this tissue, were considered valid for inclusion. The search for articles that met the premise of this study was conducted in the PubMed/MEDLINE database. In a preliminary search, 85 articles were retrieved; after in-depth investigation and assessment of the inclusion and exclusion criteria, 21 articles were selected17 reporting the effect of systemic Isotretinoin administration in humans and four analyzing the effect of this systemically administered substance in animals, specifically rats. After analyzing the selected articles, multiple reports of hyperostosis or even changes in the formation of bone structures in human patients were observed. Regarding animal studies, most addressed changes in the formation or development of bone structures caused by systemic administration of Isotretinoin. In Article 2, the objective was to evaluate the effect of Isotretinoin on bone repair after expansion of the palatal suture in rats. The sample consisted of 40 Wistar rats, divided into two groups: the control group (CG), subjected only to orthodontic movement, and the isotretinoin experimental group (IG), in which the movement occurred after drug administration. The periods of 0, 7, and 14 days after placement of the orthodontic appliance were analyzed, with a force of 30 g applied to all groups via a steel spring. After euthanasia, the maxillae were removed and analyzed using Micro-CT, histological, and histomorphometric methods. The results showed that the expander was effective in promoting expansion of the palatal suture. After 14 days, the total expansion was 381% in the CG and 299% in the IG; the percentage of blood vessels in the connective tissue increased by 145% in the CG and 84% in the IG; and bone formation in both groups occupied 52% of the expanded palatal suture. No significant differences were observed between the groups regarding collagen fiber formation.