Sato Hiromi, Shimpo Yudai, Sekiya Toshiko, Rikitake Haruna, Seki Minami, Wada Satoshi, Nomura Yoshiaki, Tomonari Hiroshi
Department of Orthodontics, School of Dental Medicine, Tsurumi University, Yokohama 230-8501, Japan.
Department of Oral and Maxillofacial Surgery, Kanazawa Medical University, Kanazawa 920-0293, Ishikawa, Japan.
J Clin Med. 2025 Jul 7;14(13):4802. doi: 10.3390/jcm14134802.
The Index of Orthodontic Treatment Need (IOTN) is widely used to assess the need for orthodontic treatment. IOTN consists of the Dental Health Component (DHC) and the Aesthetic Component (AC), evaluating malocclusion morphologically and aesthetically, respectively. However, the discriminatory power of individual DHC items and their relationship with AC grades remain unclear. This study aimed to evaluate the effectiveness of individual DHC items in school dental examinations and investigate their contribution to AC grades among junior high and high school students. A total of 726 students (443 males, 283 females; aged 12-18 years) from Tsurumi University Junior and Senior High School, excluding 168 students undergoing or having completed orthodontic treatment, were included. Nine calibrated orthodontists assessed DHC and AC using IOTN during standardized school examinations. The discriminatory power and information precision of DHC items were evaluated by Item Response Theory (IRT) analysis using three-, two-, or one-parameter logistic models depending on convergence. Correspondence analysis visualized the correlation between DHC and AC grades. Simple linear regression analyzed the contribution of each DHC item to AC grades. Orthodontic treatment need was identified in 21.1% of students. Females showed a higher rate of treatment need than males. Correspondence analysis suggested that aesthetic evaluations were more lenient than morphological evaluations. IRT and regression analysis revealed that crowding (4.d), increased overjet (2.a), and increased overbite (2.f) demonstrated high discriminatory power and significant contributions to AC grades. Among the DHC items, crowding, increased overjet, and increased overbite had higher discriminatory power for malocclusion and contributed more significantly to AC evaluations compared to other items.
正畸治疗需求指数（IOTN）被广泛用于评估正畸治疗的需求。IOTN由牙齿健康成分（DHC）和美学成分（AC）组成，分别从形态学和美学角度评估错牙合畸形。然而，各个DHC项目的区分能力及其与AC等级的关系仍不明确。本研究旨在评估学校牙科检查中各个DHC项目的有效性，并调查它们对初中和高中学生AC等级的贡献。纳入了鹤见大学初中和高中的726名学生（443名男性，283名女性；年龄12 - 18岁），排除了168名正在接受或已完成正畸治疗的学生。九名经过校准的正畸医生在标准化学校检查期间使用IOTN评估DHC和AC。根据收敛情况，使用三参数、两参数或一参数逻辑模型，通过项目反应理论（IRT）分析评估DHC项目的区分能力和信息精度。对应分析直观展示了DHC与AC等级之间的相关性。简单线性回归分析了每个DHC项目对AC等级的贡献。21.1%的学生被确定有正畸治疗需求。女性的治疗需求率高于男性。对应分析表明美学评估比形态学评估更宽松。IRT和回归分析显示，牙列拥挤（4.d）、覆盖增加（2.a）和覆牙合增加（2.f）具有较高的区分能力，且对AC等级有显著贡献。在DHC项目中，与其他项目相比，牙列拥挤、覆盖增加和覆牙合增加对错牙合畸形具有更高的区分能力，对AC评估的贡献也更显著。
