Factors associated with orthodontic pain

Abstract

Introduction: The amount of pain experienced during orthodontic treatment varies largely over time and between individuals and can affect a patient’s compliance, ability to chew, well-being and sleep quality. The reasons for the inter-individual variability in pain are largely unknown: clinical force activation, demographic psychological characteristics and genetic polymorphism of candidate genes are putative factors that may account to explain this variability.

Objective: The aim of this study was to investigate the effect of clinical, demographic, psychological and genetic factors on pain levels experienced during fixed orthodontic treatment.

Method: A convenience sample of 183 patients undergoing full fixed orthodontic treatment at the University of Otago, Discipline of Orthodontics were recruited for this study. Participants pain levels were assessed seven times over a three-day period via a smartphone App on an issued research smart phone. Clinical, demographic and psychological data were collected via questionnaire. This included the Pain Catastrophising Scale (Child Version); the Corah Dental Anxiety Scale and the State and Trait Anxiety Inventory. Participants provided a DNA sample either in the form of blood or saliva, which were used for genotyping COMT gene rs6269, rs4680, rs4646310, NR3C1 gene rs2963155 and the HTR2A gene rs9316233.

Results: Bond ups had the greatest influence on perceived levels of orthodontic pain, accounting for 20% of total variance in pain response. High pain responders had higher scores on pain catastrophizing (magnification subscale). Self-reported pain during fixed orthodontic treatment was not influenced by gender, age, time into treatment, anxiety, nor by polymorphisms of HTR2A or NR3C1 gene. AA genotype of COMT rs4646310 had higher pain levels compared to the GG and AG genotypes (p=0.048).

Conclusions: Orthodontic pain is stronger during bond ups and in patients with high catastrophizing scores. Demographics, type of clinical activations and the genetic polymorphisms investigated in this study had little impact on perceived pain levels.