Item-level analysis of the relationship between orthodontic treatment need and oral health–related quality of life in Korean schoolchildren

Introduction: This study aimed to evaluate the associations between normative orthodontic treatment need and oral health–related quality of life (OHRQoL) at an item level as well as subscale and total score levels among schoolchildren. Methods: A cross-sectional study was conducted on 2,010 randomly selected children aged approximately 8, 10, 12, and 15 years residing in the Gyeonggi province, Korea. Children were clinically examined with the Index of Orthodontic Treatment Need (IOTN). To measure OHRQoL, the Child Oral Health Impact Profile (COHIP) was used. Results: In the physical health domain of COHIP, crooked teeth, discoloration, “food sticking,” and “difficulty keeping teeth clean” were significantly associated with IOTN levels (P < 0.05), whereas pain, sensitivity and bleeding, bad breath, mouth breathing, and dry mouth were not. In addition, present and future dental health were significantly associated with IOTN levels, although self-confidence, attractiveness, and future health were not. As expected, the 5 subscale scores and total score of COHIP were significantly associated with IOTN levels after adjustment for gender, age, socioeconomic level, and caries state. Conclusions: This study suggests the importance of in-depth investigation at the item level of OHRQoL assessment scales to better evaluate the impact of malocclusion that might be alleviated by orthodontic treatment.