Content and construct validity of the Diagnostic Criteria for Temporomandibular Disorders Axis I for children

Objective To perform the content and construct validation of the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) Axis I, for children 7-11 years old. Materials and Methods A Delphi process was used to perform the content validity of the DC/TMD Axis I. One hundred eighty-nine 7- to 11-year-old children were assessed with the adapted instrument. Confirmatory factor analysis (CFA) was used to investigate construct validity of the DC/TMD for children. A baseline one-factor model was compared against a two-factor (Model 2) and a seven-factor (Model 3) models based on the original DC/TMD. Root mean squared error of approximation (RMSEA), comparative fit index (CFI), chi-square, change in chi-square and Cronbach's alpha were used to analyse the data. All analyses were performed in STATA (c) version 13.0. Results Items of the DC/TMD were reduced, "history time" was changed to 2 weeks, pain intensity was assessed through a face scale, and language was adapted to be better understood by children. The amount of muscle pressure was maintained as in the original DC/TMD Axis I. The CFA led to a two- and a seven-factor model, with good fit. The internal consistency of Model 2 was .91 and of Model 3, .94. Conclusion The results of this study provide evidence to support a seven-factor representation of the DC/TMD Axis I for 7- to 11-year-old children, as well as a two-factor structure. Such findings will begin to provide researchers with confidence in the properties of this instrument when considering its inclusion in clinical research.