title: Reliability and validity of self-assessment of mouth opening: a validation study.
abstract: BACKGROUND
  The objective of this study was to evaluate the reproducibility and validity of patients' mouth opening measurements in a research setting.
  
  
  METHODS
  Firstly, 68 patients made repeated self-measurements of mouth opening using a cardboard scale (Therabite Range of Motion Scale - TRMS). Secondly, 80 patients enrolled in a clinical trial on morbidity after lower third molar surgery, made daily assessments during the postoperative week. Patients' measurements were then compared to gold-standard clinicians' measurements.
  
  
  RESULTS
  Reliability of patients' measurements was excellent with an intraclass correlation coefficient of 0.92. The patient's measurements correlated well with the gold-standard clinician's measurements, both for the first 68 patients (Pearson's rho ranging from 0.86 to 0.90, p < 0.0001) as well as for the 80 patients enrolled in the clinical trial (rho = 0.82, p < 0.0001 at day 2, rho = 0.83, p < 0.0001 at final visit).
  
  
  CONCLUSIONS
  TRMS can be used by patients to produce reproducible and valid mouth opening measurements.
authors.affiliation: Specialist Registrar Oral Surgeon, University of Birmingham, St Chads Queensway, Birmingham B4 6NN, UK.
authors.forename: Daniel Satnam Singh
authors.initials: DS
authors.lastname: Saund
authors.forename: David
authors.initials: D
authors.lastname: Pearson
authors.forename: Thomas
authors.initials: T
authors.lastname: Dietrich
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D059026:Diagnostic Self Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009055:Mouth; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D013704:Temporomandibular Joint / Q000502:physiology*; D014081:Tooth Extraction / Q000009:adverse effects; D014313:Trismus / Q000175:diagnosis* / Q000209:etiology; D055815:Young Adult