Validity and Reliability of the Greek Version of the Psychosocial Impact of Dental Aesthetics Questionnaire (Gr-PIDAQ).

Background/Objectives: The Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) is a useful tool for investigating the psychosocial impact of malocclusion and dental aesthetics on the quality of life of young adults. This study aimed at developing a culturally adapted Greek version, assessing its validity and reliability. Methods: The questionnaire underwent bilingual translation, followed by cultural adaptation with 10 debriefing interviews. Gr-PIDAQ along with the aesthetic component of the Index of Orthodontic Treatment Need (IOTN-AC) were completed by 270 young adults for the evaluation of its psychometric properties. Fifty dentists also participated, assessing its face validity. Results: Confirmatory factor analysis verified the four-factor structure of the original version of PIDAQ. The ability of Gr-PIDAQ to discriminate between individuals according to the perceived need for improvement in dental appearance was confirmed (p < 0.001). Participants exhibiting greater malocclusion severity as assessed by the IOTN-AC presented higher PIDAQ scores (p < 0.001). Face validity was confirmed by 99.6% of participants and 96% of dentists. Cronbach's alpha coefficient of the overall scale was 0.94 (the four subscales ranged from 0.78 to 0.9), while excellent repeat measurement agreement was detected (ICC = 0.95, p ˂ 0.001). Conclusions: Our findings suggest that Gr-PIDAQ is a valid and reliable tool that can be used to measure orthodontics-related quality of life in Greek speaking adults. In terms of clinical application, it can be used to assess the orthodontic treatment need and record patients' perspective both before orthodontic treatment initiation and later during the assessment of its effectiveness, serving as a Patient-Related Outcome Measure (PROM).