歯が割れたときの関連要因の分析

Analysis of factors associated with cracked teeth.

抄録

はじめに:

本研究の目的は、米国歯内療法医学会（AAE）の明確な基準に従って、縦割れ歯の特徴、分布、関連因子を分析することであった。

INTRODUCTION: The purpose of this study was to analyze the characteristics, distribution, and associated factors of longitudinal fractured teeth according to the well-defined criteria of the American Association of Endodontists (AAE).

方法論:

103名の患者から得られた縦割れ歯17本を診断し、分析した。患者の徴候，症状，年齢，性別のほか，歯数，歯列弓，充填材料，修復物のサイズ/分類，亀裂の方向，歯髄の活力，歯内療法の有無，咬合試験結果，打診試験結果，摩耗面，歯周ポケット深さを記載した．

METHODS: One hundred seven teeth with longitudinal fracture from 103 patients were diagnosed and analyzed. The patients' signs, symptoms, age, and sex were noted as well as the tooth number, dental arch, filling materials, size/classification of restoration, crack direction, pulp vitality, whether the patient had undergone endodontic treatment, bite test results, percussion test results, wear facet, and periodontal pocket depth.

結果:

歯が割れていると診断されたのは87本（81.3％）、垂直的歯根破折（VRF、13.1％）と診断されたのは14本、歯が割れているのは4本（3.7％）、歯が折れているのは2本（1.9％）、噛み合わせテストで敏感に反応したのは82.2％であった。歯牙の縦方向の破折は40歳代の患者に最も多く観察された。上顎第一大臼歯（28.0％）が最も多く、次いで下顎第一大臼歯（25.2％）、下顎第二大臼歯（20.6％）、上顎第二大臼歯（16.8％）だった。歯牙縦割れの大部分（72.0％）は主に修復歯に発生し、無傷の歯には28.0％しか見られなかった。レジン（4.7%）やポーセレン（0.9%）に比べ、金（20.5%）やアマルガム（18.7%）などのノンボンドインレー修復材の使用は、縦歯破折の発生を増加させていた。縦断面破折歯107本のうち、33本（30.8%）が歯内療法を受け、74本（69.2%）が受けなかった。VRFは歯内療法と関連していた。

RESULTS: Eighty-seven teeth were diagnosed with a cracked tooth (81.3%), 14 were diagnosed with vertical root fracture (VRF, 13.1%), 4 had a split tooth (3.7%), and 2 had a fractured cusp (1.9%); 82.2% showed a sensitive reaction on the bite test. Longitudinal tooth fractures were observed most frequently in patient in their 40s. The upper first molar (28.0%) was most frequently cracked, followed by the lower first molar (25.2%), the lower second molar (20.6%), and the upper second molar (16.8%). Most longitudinal tooth fractures (72.0%) occurred mainly in restored teeth, whereas only 28.0% were found in intact teeth. Compared with resin (4.7%) or porcelain (0.9%), the use of nonbonded inlay restoration materials such as gold (20.5%) or amalgam (18.7%) increased the occurrence of longitudinal tooth fractures. Out of 107 of longitudinal fractured teeth, 33 (30.8%) were treated endodontically and 74 (69.2%) were not. VRF was associated with endodontic treatment.

結論:

症状を再現するためには、咬合検査が最も確実です。亀裂の発見や歯の全方向の精密な検査には、さまざまな検査方法を併用することが推奨されています。

CONCLUSIONS: The bite test is most reliable for reproducing symptoms. The combined use of various examination methods is recommended for detecting cracks and minutely inspecting all directions of a tooth.