The eruption sequence of first molars and central incisors in elementary school children born in 1996
| Jazyk: | japonština |
|---|---|
| Rok vydání: | 2016 |
| Předmět: | |
| Zdroj: | 岐阜歯科学会雑誌 = The Journal of Gifu Dental Society. 43(1):19-26 |
| ISSN: | 2433-0191 |
| Popis: | 近年我が国では、う蝕の減少をはじめとして小児の口腔健康状態は劇的に変化している。また、従来から用いられている永久歯の萌出順序については、最も早く萌出するとされていた下顎第一大臼歯と下顎中切歯の萌出順序が1970年代に生まれた小児で入れ替わり、大規模調査でも、下顎第一大臼歯と下顎中切歯では、下顎中切歯の方が萌出の早いことが確認されている。萌出順序の変化は、永久歯の咬合形成にも影響を与える要因であり、小児う蝕の予防対策を構築してく上でも重要である。これまでの報告のように、萌出時期や萌出順序が経年的に変化するものであるならば、永久歯の中で萌出の早い上下顎中切歯と上下顎第一大臼歯の4歯種の萌出順序にさらなる変化が起こる可能性も考えられる。本研究では、近年における永久歯の萌出状況を調査し検討する目的で、岐阜県某市の4小学校で入学時から卒業前までの歯科検診を受診した1996年度生まれの児童を対象として、検診結果より上下顎第一大臼歯と上下顎中切歯の萌出状態を抽出し、歯種別の萌出率の算出、および萌出をエンドポイントとして生存分析を行った。その結果、本研究の1996年度生まれの児童の萌出順序は男女とも、下顎中切歯、下顎第一大臼歯、上顎第一大臼歯、上顎中切歯の順であり、1970年代に生まれた者で、最初に萌出する永久歯が下顎第一大臼歯から下顎中切歯に入れ替わってから変化していないことが確認された。 There have been dramatic changes in the state of childhood oral health in Japan in recent years, such as the reduction in childhood caries. In addition, according to the eruption sequence for permanent teeth that has been used to date, the teeth that erupt earliest are the mandibular first molar and then the mandibular central incisor. However, a large-scale study performed on children born in the 1970s conversely confirmed that the mandibular central incisor erupts earlier than the mandibular first molar. Changes in the eruption sequence are factors that also affect the occlusal morphology of the permanent teeth, and are an important component of the preventive management of childhood caries. If - as reports to date have suggested - the timing of eruption and the eruption sequence are factors that change over time, then we believe further changes in the eruption sequence of the four teeth that erupt earliest can be expected. These four types of teeth are the upper and lower central incisors and the upper and lower first molars. The purpose of the present study was to survey and investigate the eruption status of permanent teeth in recent years. This was achieved by performing dental health checkups on students who were born in 1996 from the time they entered school until they graduated. The study was conducted in four elementary schools in a certain town in Gifu prefecture. We then extracted the state of eruption of the upper and lower first molars and the upper and lower central incisors from the investigation results, and calculated the eruption rate by tooth type and performed a survival analysis using eruption as an endpoint. Results showed that the eruption sequence for male and female children born in 1996 occurred in the following order : mandibular central incisor, then mandibular first molar. This shows that the first permanent teeth to erupt have not changed from the mandibular first molar to the mandibular central incisor since the study performed in 1970. |
| Databáze: | OpenAIRE |
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