親指や指（趾）のしゃぶりが原因で起こる乳歯列の損傷

Damage to the primary dentition resulting from thumb and finger (digit) sucking.

抄録

1歳児では約50％が親指や指をしゃぶっていると言われています。その数は4〜5歳までに急速に減少します。この習慣が自然になくなる平均年齢は3.8歳です。指しゃぶりによって生じる不正咬合としては，前方開咬が最も多く報告されている．本研究では，3歳，4歳，5歳の3つの年齢層で，乳歯列の前方および後方部における親指および指しゃぶりの影響を調査した．調査対象者は930名である。非口腔習慣群と親指・指しゃぶり群のデータを比較した．すべての年齢で，親指・指しゃぶり群は非口腔習慣群よりも開咬と上顎前突の頻度が高かった．この頻度は年齢と関係ないように思われた。4歳以降も咬み合わせを維持した場合、永久歯列不正の傾向が強まるようであった。

It is estimated that approximately 50 percent of infants at one year of age suck a thumb or finger. The number decreases rapidly by ages four to five years. The average age for spontaneous cessation of the habit is 3.8 years of age. Anterior open bite is the most frequent malocclusion reported with digit sucking. In this study the authors investigated the influence of thumb and finger-sucking in the anterior and posterior sections of the primary dentition in three age-groups: three, four, and five years. The study population included 930 subjects. Data for the non-oral-habit group were compared with the data for the thumb and/ or finger-sucking group. At all ages the frequencies of open-bite and maxillary protrusion for the thumb and finger-sucking group were higher than the non-oral-habit group. The frequencies did not appear age-related. There appeared to be an increased tendency to a permanent malocclusion in children who continued after four years of age.