Cross-cultural adaptation and psychometric validation of the OHIP-TMDs for Portuguese-speaking populations: A unified version for Brazil and Portugal

OBJECTIVE: To conduct the cross-cultural adaptation and psychometric validation of the OHIP-TMDs for Portuguese-speaking populations, developing a unified version that encompasses both European and Brazilian Portuguese variants. METHODS: A bicentric observational study was conducted according to Beaton's guidelines and COSMIN standards. The instrument underwent translation, expert review, and pre-testing. Psychometric validation included 211 individuals with TMD (Portugal: n=98; Brazil: n=113). Internal consistency (Cronbach's α, McDonald's ω), test-retest reliability (ICC), structural validity (CFA), convergent validity (Fonseca Anamnestic Index), and known-groups validity were assessed separately for each country. RESULTS: The OHIP-TMDs-PT demonstrated excellent internal consistency (α=0.98 PT; α=0.96 BR) and reliability (ICC=0.96 PT; ICC=0.94 BR). CFA supported a unidimensional structure in Portugal and a second-order model in Brazil. Strong convergent validity and significant known-groups differences were observed. CONCLUSION: The OHIP-TMDs-PT is a reliable and valid instrument for assessing oral health-related quality of life in individuals with TMD across Lusophone populations.