Background: Pain, a common experience reported by patients under orthodontic treatment, results from force application to the teeth and trauma caused by attrition of brackets and wires against the underlying oral mucosa. The main protection of the mucosa is secretory immunoglobulin A (sIgA), which may play a fundamental role in integrity maintenance and whose production may be reduced as a result of the stress of orthodontic treatment. The aim of this study was to assess sIgA levels in the saliva and their correlation with oral pain intensity in adults and children after the installation of fixed orthodontic appliances.
Material/Methods: Twenty patients (10 children, age 11–13 years; 10 adults, age 18–37 years) were assessed before treatment, after bracket bonding, and after initial arch wire insertion. Saliva was sampled for sIgA analysis, and oral pain was assessed through a visual analog scale.
Results: Although there was a trend toward reduction of the salivary sIgA levels during the initial arch phase in the children, and during the bonding and initial arch phases in the adults, this finding was not significant.
Conclusions: There was a trend toward a negative correlation of oral pain intensity and salivary sIgA levels in the children, which may indicate the importance of sIgA for oral protection during orthodontic treatment, interfering with the pain experienced by the patients.

Keywords: Pain - metabolism, Orthodontic Wires - adverse effects, Immunoglobulin A, Secretory - metabolism, Child, Adolescent, Pain Measurement, Saliva - metabolism, young adult