Abstract
Up to 95% of orthodontic patients report pain during orthodontic treatment, with up to 10% of patients interrupting their treatment due to the pain experienced. Pain is highly subjective: there is a range of pain response among individuals undergoing orthodontic treatment, with some patients feeling high levels of pain and others just mild discomfort. The reasons for this variability are largely unknown. Objective: To investigate factors that may be associated with orthodontic pain experience. Methods: First, 107 participants were screened for pain response over 48 hours following placement of orthodontic elastomeric separators. Second, the highest (n=10) and lowest (n=10) pain responders were identified and data collected on age, ethnicity, sex, self-rated oral health, anxiety, mood, dental anxiety and fear, catastrophising, general sensitivity (cold) and tooth sensitivity. They also provided a saliva sample for Catechol-O-Methyltransferase (COMT) gene sequencing. Results: Statistically significant differences between high and low pain responders were identified with the Pain Catastrophising Scale (PCS), Dental Anxiety Scale (DAS) and Cold Pressor Tests. Multivariate analysis was carried out using a generalised linear model. The empty model showed that 39.3% of pain response type (high or low) is explained by the magnification subcategory of the PCS; once all other variables were controlled for, the adjusted model explained 80% of the variance in the magnification subscale of the PCS. Of the three single nucleotide polymorphisms of the COMT gene analysed, only rs6269 showed an association with pain responders’ haplotypes (albeit marginal). Conclusions: Pain catastrophising, dental anxiety and cold sensitivity appear to modify orthodontic pain experience. A few simple screening questions may help to identify patients at risk prior to commencing orthodontic treatment, so that patient-specific management strategies can minimise orthodontic discomfort.