Comparison of the Effects of Ibuprofen and Low-Level Laser Therapy on Orthodontic Pain By Means of Interleukin 1-Beta and Substance P Levels in the Gingival Crevicular Fluid

Pain is defined as a sophisticated experience that includes sensations evoked by, and reactions to noxious stimuli. During the different phase of orthodontic treatment, pain is developed in response to the tension and pressure zones generated in the periodontal ligament following the force application. This leads to the secretion of inflammatory mediators such as histamine, serotonin, dopamine, glycine, cytokines, leukotrienes, prostaglandins and substance P that stimulate free nerve endings resulting in the perception of pain.

Early orthodontic pain is usually caused by the insertion of elastomeric separators to the mesial and distal of the tooth to be banded in order to create adequate space for proper placement. Recent studies have demonstrated that the pain reaches its peak at 24 hours and then gradually decreases within 7 days. The intensity of this pain is sometimes perceived as extremely high to cause a significant number of patients to discontinue the treatment.

Nonsteroidal anti-inflammatory drugs, which block the prostaglandin synthesis through inhibiting the cyclooxygenase activity, is one of the most common methods used to manage the orthodontic pain. It has been reported that these drugs decrease the orthodontic tooth movement rate, in addition to many systemic side effects such as gastric and duodenal ulceration, coagulation disorders, congestive heart problems and allergic effect.

The application of low-level laser therapy (LLLT) also reported being efficient in accelerating orthodontic tooth movement and in alleviating orthodontic pain without any apparent side effects. LLLT is thought to reduce the pain by increasing the local blood flow, inhibiting the secretion of inflammatory substances, inducing the release of neurotransmitters, altering the conduction and excitation of peripheral nerves and stimulating the endorphins release. On the other hand, literature review on the effectiveness of LLLT in alleviating orthodontic pain observed after elastomeric separator placement (ESP) exhibited conflicting results. While LLLT was found to be effective in some studies, the others refuted its effectiveness.

The intensity of orthodontic pain was evaluated either subjectively by visual analog scale (VAS) or objectively by chemical analysis of gingival crevicular fluid (GCF), in previous studies. The analysis of GCF is a useful and non-invasive method for detecting the biochemical mediators released during tooth movement with reasonable sensitivity. In GCF, pro-inflammatory mediators such as interleukin 1-beta (IL-1β) and prostaglandin E2 (PGE2) and neuropeptides such as Substance P (SP) have been related separately to pain. When studies on alleviating orthodontic pain observed after ESP were reviewed, it was determined that the effects of many drugs and LLLT were evaluated subjectively by VAS. Furthermore, only in one study, the effects of ibuprofen and LLLT were compared using PGE2 levels in GCF and VAS. Based on that, this study was aimed to compare the effects of ibuprofen and LLLT in alleviating orthodontic pain observed after ESP through IL-1β and SP levels in GCF and VAS. The null hypothesized was that there was no difference between the effects of ibuprofen and LLLT in orthodontic pain relief.