小児の歯列および咬合状態の成長発達に関する縦断研究 : 咬合の推移について

A Study on Growth and Development of Dentition and Occlusion in Children : Changes of Occlusion

Kaihara Yasutaka

Saiga Kaori

Nakae Hisami

Kuramoto Meiko

Makihira Mika

Miyamoto Yoko

Suzuki Junji

Amano Hideaki

Miura Kazuo

Kawabata Yasushi

Kozai Katsuyuki

小児歯科学雑誌

小児の歯列および咬合状態の推移について, 縦断的な検討を行うことを自的とし, 歯列研究用模型を用いた調査を行った。歯冠崩壊をした歯を有さず, 咬合誘導治療を受けていない男児17名, 女児10名, 計27名の日本人小児の, 4歳から12歳に至るまで, 毎年行った印象採得で得られた研究用模型を資料とした。対象資料に関して, 乳歯列から永久歯列へ至るまでの間, 乳歯の空隙, 咬合状態, 臼歯の咬合関係, 咬合の推移について検討を行い, 以下の結果を得た。

1. 乳歯列の空隙は, 男女ともに, 発育空隙と霊長空隙が両方みられるものが最も多かった。また, 男女ともに, 上顎より下顎のほうが, 空隙がない歯列の割合が多い傾向が認められた。

2. 正常咬合の割合は, 5歳時は, 男児47.7%, 女児50.0%であったが, 12歳時には男児23.5%, 女児30.0%となった。また, 4歳から12歳までの間で, 最も増加した不正咬合は叢生であった。

3. ターミナルプレーンについては, 両側とも垂直型の発現頻度が男児64.7%, 女児60.0%と最も多かった。第一大臼歯の咬合関係は, Ⅰ級が男児76.5%, 女児80.0%と最も多く, 次いでⅡ級, Ⅲ級の順であった。ターミナルプレーンと第一大臼歯の咬合関係は, 垂直型からⅠ級に移行するものが最も多くみられた。

4. 同一個人の乳歯列期と永久歯列期を比綬検討した結果, 乳歯列期に正常咬合であったものは59.3%で, そのうら永久歯列でも正常咬合であったものは62.5%であった。また, 乳歯列に過蓋咬合であったものは, 殆どが不正咬合に移行した。

The purpose of this study was to examine the longitudinal change of occlusion in children. The materials were study models obtained annually from 27 patients (17 boys and 10 girls) aged 4 to 12, having no history of significant tooth decay or orthodontic treatment. The interdental spaces in the primary dentition, the anterior occlusal relationship, the terminal plane, the relationship of the permanent first molar, and the change of occlusion from the primary dentition to the permanent dentition, were discussed.

The results of this study were as follows:

1. The majority of interdental spaces in the primary dentition was observed to be the developmental and primate space for both sexes.

2. The percentage of normal occlusion at 5 years of age was 47.7% for boys and 50.0% for girls; at 12 years of age it was 23.5% for boys and 30.0% for girls. The type of abnormal occlusion that increased mostly between the ages of 4 and 12 was crowding of teeth.

3. The terminal plane was most frequently observed for both the horizontal and vertical types. The most common type of occlusion for front molars was the Class I relationship, followed by the Class II and Class III relationships, in that order. The majority has been observed to shift from the vertical type to the Class I relationship.

4. Of the cases where there was normal occlusion in the primary dentition period, 62.5% had normal occlusion for the permanent dentition. Most of the cases of overbite in the primary dentition period progressed to malocclusion.

Thusly, the percentage of those with normal occlusion decreases with age, and in many cases, malocclusion does not heal spontaneously. We can therefore conclude that this suggests the need to provide occlusal guidance concerning dental heath of patients in childhood.

Longitudinal study

Dentition

Occlusion

Study model

Medical sciences [ 490 ]

jpn

日本小児歯科学会

Copyright (c) 2005 Authors, 日本小児歯科学会

[ISSN] 0583-1199

[NCID] AN00116228