title: No Increased risk of temporomandibular disorders and bruxism in children and adolescents during orthodontic therapy.
abstract: OBJECTIVE
  Whether orthodontic therapy is a risk factor for temporomandibular disorders (TMD) or parafunctional habits such as bruxism is a question that has long been discussed. The issue is highly relevant to public health due to the frequency of these functional disorders in the general population and the sheer number of orthodontic treatments. The aim of this cross-sectional study was to investigate the risk of TMD or bruxism in children and adolescents during orthodontic therapy.
  
  
  METHODS
  The study included 1,011 children and adolescents between the ages of 10 and 18 selected at random from the general public who had been examined for signs of TMD using the Helkimo index and Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Parafunctional activities (bruxism) were surveyed and documented in reference to wear effects on the front teeth using the method developed by Egermark-Eriksson. In addition, probands were asked about their current orthodontic treatments.
  
  
  RESULTS
  Nearly 30% (N = 296) of the probands stated that they were undergoing orthodontic therapy. Roughly 1/10 proband presented with a clinical TMD according to the Helkimo index (9.6%; N = 97) or a TMD diagnosis according to the RDC/TMD (10.2%; N = 102). After controlling for the effects of age, gender and school-type using a multinomial logistical regression analysis there was no increased risk of anamnestic or clinical TMD symptoms or diagnoses during orthodontic treatment (odds ratios between 0.63 and 1.18; all p-values > 0.05). At the same time, both wear facets on the front teeth (tooth-related mean value with vs. without appliance: 0.12 vs. 0.16; t test: p = 0.038) and self-reported bruxing be havior (OR = 0.57; p = 0.018) were significantly reduced by orthodontic treatment.
  
  
  CONCLUSIONS
  Our study revealed no increased risk of TMD in children and adolescents during orthodontic therapy, which seems to reduce parafunctional activities and thus the likelihood of noncarious dental damage.
authors.affiliation: Department of Pediatric and Preventive Dentistry, University of Leipzig, Leipzig, Germany. christian.hirsch@medizin.uni-leipzig.de
authors.forename: Christian
authors.initials: C
authors.lastname: Hirsch
mesh_terms: D000293:Adolescent; D002012:Bruxism / Q000453:epidemiology; D002648:Child; D015897:Comorbidity; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D009971:Orthodontics, Corrective / Q000706:statistics & numerical data*; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D013705:Temporomandibular Joint Disorders / Q000453:epidemiology*