Pain discomfort and crevicular fluid changes induced by orthodontic elastic separators in children

The objective of the present investigation was to study the experience of pain after placement of orthodontic elastic separators and the possible associations with the gingival crevicular fluid (GCF) composition changes at the level of interleukin 1-beta (IL-1beta), substance P (SP), and prostaglandin-E2 (PGE2). Eighteen children (mean age 10.8 yrs) in the beginning of the orthodontic treatment were included. Molar elastic separators were inserted mesially to 2 first upper or lower molars. One of the antagonist molars served as control. The GCF was collected from the distobuccal and distopalatal sites from each molar, before (day -7, day 0) and after the placement of separators (1 h, day 1, and day 7). Pain intensity was recorded using a visual analog scale (VAS). The contents of IL-1beta, SP, and PGE2 were determined by enzyme-linked immunosorbent assay. Pain intensity increased after 1 h (VAS = 11) and remained high on day 1 (VAS = 13). On day 7, no significant pain was reported. After 1 h, 1 day, and 7 days, mean GCF IL-1beta levels were significantly elevated at treatment teeth compared to control teeth (highest day 1). The GCF levels of SP and PGE2 for the treatment teeth were significantly higher at day 1 and day 7 than the control teeth. All 3 mediators remained at baseline levels throughout the experiment for the control teeth. The intensity of pain at 1 h was associated to PGE2 levels (R2 = 0.38; P < .05), whereas at day 1, the intensity of pain was associated to IL-1beta levels (R2 = 0.63, P < .0001). Thus, we report a rapid release of biochemical markers (1 h) that peaked after 1 day and partially decreased 7 days later. The intensity of pain followed a similar pattern. Associations were found between the experience of pain intensity and the GCF mediator levels.

The study may help to detect, in an initial stage, individuals prone to perceive higher level of pain during orthodontic treatment. This may help in the development of methods that will better control and/or alleviate the discomfort of pain during tooth movement.