中国錦州市における6～12歳の小児における混合歯列不正咬合の有病率と影響因子

Prevalence and Influencing Factors of Mixed Dentition Malocclusion in Children Aged 6-12 Years in Jinzhou, China.

抄録

目的:

中国錦州市の小学生における不正咬合の有病率、臨床症状および関連する危険因子を調査すること。

PURPOSE: To investigate the prevalence, clinical manifestations and related risk factors of malocclusion in schoolchildren of Jinzhou City, China.

材料および方法:

錦州市の各地区から6～12歳の小児2162人を無作為に抽出した。口内科医による従来の臨床検査が実施され、不正咬合のさまざまな臨床症状と個々の正常咬合に基づいて結果が記述された。さらに、児童の両親または保護者が記入したアンケート調査によって、人口統計学的データ、生活習慣、口腔習慣が提供された。個々の正常咬合と不正咬合の分布はパーセンテージで記録し、2因子分析にはピアソンのΧ2を用いた。データはSPSSソフトウェア（バージョン25.0）を用いて統計的に分析し、有意水準はα=0.05とした。

MATERIALS AND METHODS: A total of 2162 children aged 6-12 years were randomly selected from various districts of Jinzhou. Conventional clinical examination was performed by stomatologists, and the results were described based on different clinical manifestations of malocclusion and individual normal occlusion. Further, a questionnaire survey completed by children's parents or guardians provided the demographic data, lifestyle, and oral habits. The distribution of individual normal occlusion and malocclusion was documented in percentage, and Pearson's Χ2 was used for two-factor analysis. The data were statistically analysed using SPSS software (version 25.0) with a significance level of α = 0.05.

結果:

本研究には、男児1129名、女児1033名、すなわち、それぞれ全体の52.2％、47.8％が組み入れられた。錦州市の6～12歳の小児の不正咬合の有病率は67.9％で、そのうち叢生歯列が71.8％と最も多く、次いで深い過蓋咬合、前方交叉咬合、歯列間隔、深いオーバージェット、前方端と端の咬合、前方開咬であった。ロジスティック回帰モデルの結果、BMI指数は不正咬合の発生にほとんど影響しなかったが（p＞0.05）、う蝕、悪い口腔習慣、乳歯の保定、低い唇側小窩裂溝はすべて不正咬合の発生に関連していた（p＜0.05）。さらに、悪い口腔習慣の頻度および期間が高いほど、不正咬合の可能性が高いことと関連していた。

RESULTS: A total of 1129 boys and 1033 girls were included in this study, i.e. 52.2% and 47.8% of the total number of children, respectively. The prevalence of malocclusion in children aged 6-12 years old in Jinzhou was 67.9%, of which crowded dentition was the most common form, with a prevalence of 71.8%, followed by deep overbite, anterior crossbite, dental spacing, deep overjet, anterior edge-to-edge occlusion, and anterior open bite. In the logistic regression model, the results showed that BMI index had little effect on the occurrence of malocclusion (p > 0.05), while dental caries, bad oral habits, retained primary teeth, and a low labial frenum were all related to the occurrence of malocclusion (p < 0.05). Moreover, the higher frequency and duration of bad oral habits were associated with a higher likelihood of malocclusion.

結論:

錦州の6～12歳の小児における不正咬合の有病率は高い。また、悪い口腔習癖（口唇を咬む、舌を突き出す、物を咬む／かじる、片側顎支持、片側咀嚼など）およびその他の関連する危険因子（う蝕、口呼吸、乳歯の保定、低口唇小帯など）は、不正咬合と関連していた。

CONCLUSIONS: The prevalence of malocclusion in children aged 6-12 years in Jinzhou is high. In addition, bad oral habits (such as lip biting, tongue thrusting, biting/gnawing objects, unilateral chin supporting, and unilateral mastication) and other related risk factors (such as dental caries, mouth breathing, retention of primary teeth, and low labial frenum, etc) were associated with malocclusion.