エナメル質亀裂の発生状況と関連症状に関する臨床調査  [in Japanese] The Prevalence and Related Symptoms of Enamel Cracks : A Clinical Survey  [in Japanese]

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Author(s)

    • 韓 臨麟 HAN Linlin
    • 新潟大学大学院医歯学総合研究科口腔健康科学講座う蝕学分野 Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences
    • 岡本 明 OKAMOTO Akira
    • 新潟大学大学院医歯学総合研究科口腔健康科学講座う蝕学分野 Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences
    • 福島 正義 FUKUSHIMA Masayoshi
    • 新潟大学歯学部口腔生命福祉学科口腔介護支援学講座 Department of Oral Health and Welfare, Niigata University Faculty of Dentistry
    • 興地 隆史 OKIJI Takashi
    • 新潟大学大学院医歯学総合研究科口腔健康科学講座う蝕学分野 Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences

Abstract

エナメル質亀裂(以下:亀裂)は外傷による歯の破折の最も軽度な変化であるとともに,明確な外傷既往のない歯においてもしばしば観察される一方,エナメル質内に限局した歯冠長軸にほぼ平行に走行する複数の微細な亀裂がよく観察される.この種の亀裂は,二次う蝕・歯の審美障害・歯の破折・歯髄疾患などのさまざまな病態の誘因になりうると考えられるものの,その成因や発生頻度の詳細についていまだ不明の点が多い.本研究では,この種の亀裂の発生頻度や随伴する臨床症状について調査を行った.残存歯20本以上の外来患者80名(10代後半から80代までの各年齢層について各10名,ただし,80代の被験者の残存歯は,平均16.5本であった)を調査対象とし,診療用ライトによる照明下で歯鏡,歯科診療用ルーペ,コンポジットレジン重合用光照射器などの器具を用いて,亀裂の程度,修復物の有無と種類,および冷刺激に対する誘発痛の有無を診査した.亀裂の程度については,肉眼で容易に確認できる場合をレベルC,ルーペによる拡大視で確認できた亀裂をレベルB,光照射器で光を当てた状態で拡大視下で確認できた場合をレベルAとした.また,誘発痛に関しては,スリーウェイシリンジを用いて亀裂歯に冷気を当てて診査した.その結果,亀裂の検出率は年齢とともに上昇傾向を示し,50代以後では100%の被験歯に亀裂が確認できた.また,10代〜30代の被験者では,コンポジットレジンあるいはメタルインレー修復歯が非修復歯と比較して高い亀裂検出率を示す傾向がみられた.さらに,若年者では亀裂は主としてレベルAに分類されたが,加齢に伴ってレベルB,次いでレベルCの亀裂の割合が増加した.一方,冷刺激による誘発痛は,20代〜60代の被験者では亀裂歯の13.0〜16.7%に認められたが,その検出率に年齢による明瞭な相違はみられなかった.以上より,エナメル質亀裂が年齢とともに進展を示すことが明確に確認されるとともに,その発生ないし進行要因として修復処置が関連する可能性が示唆された.また,エナメル質亀裂が象牙質知覚過敏症様の症状発現に関連する可能性も推察されたが,この種の症状と亀裂の程度との明瞭な関連はみられなかった.

Enamel cracks, although generally regarded as a minor symptom in tooth fracture occurring with an external injury, are frequently detected in teeth without any history of injury. These cracks may be recognized as multiple thin lines that run parallel to the tooth axis. Although the cracks might cause several clinical problems such as secondary caries, esthetic disorders, tooth fracture and pulp diseases, they are frequently neglected and their causes and frequencies have not yet been fully studied. Therefore, this clinical survey investigated the frequency of enamel cracks and related symptoms. Eighty patients ranging from teenagers to those in their eighties, all underwent a clinical tooth examination. In each age group, 10 patients were investigated. The enamel cracks were divided into three types (A, B and C) based on differences in the progression of the crack: an enamel crack that was easily confirmed by a simple observation was classified as level C, those confirmed by observation through a magnifying glass were level B, and those confirmed using an activator light and a magnifying glass were level A. Cold air was used to assess the thermal sensitivity of cracked teeth. The results demonstrated that there was a tendency of increased crack incidence with aging, and the incidence was 100% in subjects≧50 years of age. A high incidence was observed in teeth restored with composite resin or a metal inlay restoration in comparison to non-restored teeth in subjects <40 years of age. Level A cracks were the most frequent in young subjects, whereas the frequencies of cracks of levels B and C increased with aging. The frequency of cracked teeth sensitive to cold air was 13.0-16.7% in 20- to 69-year-old subjects, and was not different among various age groups. In conclusion, this study clearly demonstrated age-dependent progression of enamel cracks, suggesting that operative procedures may trigger the formation and/or propagation of enamel cracks. Enamel cracks could be related to the pain response upon cold stimulus, although the frequency of sensitive teeth was not dependent on crack progression.

Journal

  • The Japanese Journal of Conservative Dentistry

    The Japanese Journal of Conservative Dentistry 51(6), 614-621, 2008

    The Japanese Society of Conservative Dentistry

References:  19

Cited by:  2

Codes

  • NII Article ID (NAID)
    110007026967
  • NII NACSIS-CAT ID (NCID)
    AN00191201
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    0387-2343
  • Data Source
    CJP  CJPref  NII-ELS  J-STAGE 
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