Association Between Index of Orthodontic Treatment Need (IOTN) and Child Oral Health Impact Profile (COHIP) Among 8 to 15 Year-Old Schoolchildren

Objectives: Malocclusion can have negative impact on Oral Health Related Quality of Life (OHRQOL) among schoolchildren. The purpose of this study was to evaluate the association between Child Oral Health Impact Profile (COHIP) and Index of Orthodontic Treatment Need (IOTN) among Korean schoolchildren aged 8 to 15 years old, and to assess whether the above association differs by different age groups of children.
Methods: The sample consisted of 2,010 children in their school years 8, 10 12 and 15. A dental examination procedure was conducted and a structured questionnaire was implemented. OHRQOL was assessed with COHIP questionnaire, which was composed of 34 questions under five subscales. A dentist examined subjects for functional malocclusion according to the IOTN. The relationship between COHIP (total score, subscales, each item) and IOTN was examined using Kruskal-Wallis test, chi-square test and spearman correlation test.
Results: Kruskal-Wallis test result showed that COHIP total and subscale scores were different by different orthodontic treatment need groups assessed with IOTN (P<0.001). Chi-square test result showed that most items in functional and social-emotional subscales were associated with IOTN, while only one item in oral health and self-image subscales were associated with IOTN. In terms of oral health subscale, crooked teeth or spaces was associated with IOTN (P<0.05). The COHIP score and each COHIP subscale were negatively correlated with IOTN (P<0.05). In terms of age differences, IOTN was associated with more COHIP subscale scores as age increases (p<0.05).
Conclusions: Among Korean schoolchildren, IOTN and OHRQOL were negatively correlated. Generally as age increases IOTN was associated with more subscale scores. Improving malocclusion status may contribute to increase OHRQOL among school children.