Effects of Transmucosal Thyroxine Administration on the Tooth Movement in an Animal Model

Medications and Orthodontic Tooth Movement: What Accelerates and Diminishes Tooth Movement?

The biological aspect of orthodontic tooth movement is influenced by the magnitude and duration of the applied force. This initiates signaling cascades essential for bone remodeling, which involve activating various cell signaling pathways that enhance the metabolism of the periodontal ligament, leading to localized bone resorption and deposition. This process facilitates tooth movement on the pressure side and promotes healing on the tension side. The remodeling associated with orthodontic tooth movement is an inflammatory reaction involving mediators. Key components in this process include hormones, systemic influences, cyclic adenosine monophosphate, specific cytokines like interleukin 1, colony-stimulating factors, calcium, collagenase, and prostaglandins, all of which are essential for the biological adjustments necessary for tooth movement. Medications that influence molecular pathways critical for the homeostasis of periodontal tissues or that affect changes during orthodontic tooth movement and clastic cell regulation can potentially modulate tooth movement. With the recent increase in prescription medication use, it is essential for clinicians to be aware of medication consumption in prospective patients and understand its potential impact on orthodontic treatment. This review aimed to explore the effects of commonly prescribed medications on the rate of orthodontic tooth movement, thoroughly review the existing evidence on this topic, and identify potential areas for future research.

Local hormones and growth factors to enhance orthodontic tooth movement: A systematic review of animal studies

BACKGROUND

Prolonged treatment times are the main reason capable of affecting patient compliance with orthodontic treatment.

OBJECTIVES

A systematic review was made to determine whether the local administration of hormones and growth factors effectively enhances orthodontic tooth movement, and to identify possible adverse effects in animal studies.

MATERIALS AND METHODS

Five databases (PubMed, Scopus, EMBASE, Web of Science and Cochrane Library) were checked for experimental studies reporting one of the following outcomes: orthodontic tooth movement, histological outcomes and side effects. After data extraction, orthodontic tooth movement linked to adjunctive substances was analysed using forest plots. The risk of bias and the quality of evidence were determined with the SYRCLE tool and the GRADE tool, respectively.

RESULTS

Twenty-four studies were included in the systematic review. On a specific dose level, epidermal growth factor + liposomes, fibroblast growth factor and prostaglandin E₂  + Ca were supported by a moderate level of evidence and rated as highly effective in increasing tooth movement in animal models. Likewise, there was histological evidence of increased bone remodelling after the administration of these substances. Other compounds were supported by a low to very low level of evidence.

CONCLUSIONS

Hormones and growth factors may have a relevant impact upon orthodontic tooth movement rate. In specific formulations, prostaglandin E₂ , fibroblast growth factor and epidermal growth factor showed promising results.

Influence of thyroxine supplementation on orthodontically induced tooth movement and/or inflammatory root resorption: A systematic review

The role of thyroxine administration on orthodontically induced tooth movement and/or inflammatory root resorption remains unclear. The aim was to assess the influence of thyroxine administration on orthodontically induced tooth movement and/or inflammatory root resorption. The study protocol was registered in PROSPERO (CRD42020164151). An electronic search of indexed databases was conducted without time or language restrictions up to and including May 2020. The following eligibility criteria were imposed: (a) original prospective controlled clinical studies and/or experimental studies on animal models; (b) subjects undergoing orthodontic therapy with fixed appliances; (c) presence of a control group [orthodontic tooth movement without thyroxine administration]; and (d) intervention: orthodontic tooth movement with thyroxine administration. Review articles, commentaries, letters to the editor, case reports/series, studies with no control group, cross-sectional studies, retrospective studies and studies where thyroxine was administered along with other interventions such as calcitonin and prostaglandins were excluded. Quality of available evidence and risk of bias within studies were assessed. Any disagreements were resolved via consensus discussions. Based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, 8 animal studies were included. Four studies reported that thyroxine administration increases the rate of orthodontic tooth movement; 3 studies did not show a significant difference. Three studies showed that thyroxine administration decreases orthodontically induced inflammatory root resorption; 2 studies found no significant difference. The risk of bias among studies was high. In conclusion, the influence of thyroxine administration on orthodontic tooth movement and/or orthodontically induced inflammatory root resorption in animal models remains unclear.