下顎第二大臼歯のう蝕有病率と第三大臼歯の衝突との関連

Association of Prevalence of Dental Caries in Mandibular Second Molar with Impacted Third Molar.

抄録

背景:

埋伏歯とは、3分の2の歯根形成後も咬合面に到達しない歯のことである。衝突歯に関連する症状には、三半規管、嚢胞性病変、第二大臼歯の頚部齲蝕などがある。本研究の目的は，下顎第二大臼歯の遠位面におけるカリエス病変の発生と，下顎第三大臼歯の存在との関連性を評価することである。

BACKGROUND: An impacted tooth is a tooth which does not reach the occlusal plane even after two-thirds root formation. Conditions associated with impacted teeth include trismus, cystic lesions, and cervical caries of second molars. The objective of this study was to evaluate the occurrence of carious lesions in the distal aspect of the mandibular second molar and its association with the presence of mandibular third molars.

方法は以下のとおりです。:

2018年9月から2020年9月まで横断的研究を行った。参照番号90/77/78のInstitutional Review Committeeから承認を得た。18歳以上の患者のオルソパントモグラフィーを調査した。年齢、性別、下顎第二、第三大臼歯の情報を記録した。便利なサンプリングを行った。統計解析はStatistical Package for Social Sciences version 21を用いて行った。

METHODS: A cross-sectional study was conducted from September 2018 to September 2020. Approval was taken from the Institutional Review Committee with reference number 90/77/78. Orthopantomograms of patients aged 18 years or older were studied. Information on age, gender, mandibular second and third molars were recorded. Convenient sampling was done. Statistical analysis was done using Statistical Package for Social Sciences version 21.

結果:

合計626枚のX線写真を調査した結果、mesioangular impaction（35.3％）が最も顕著なタイプであり、次いでhorizontal impactionが第二大臼歯の遠位カリエスの原因となっていた。第二大臼歯の遠位カリエスは、20歳から40歳の年齢層と女性に多く見られた。性別と虫歯の有無（p＝0.00），インパクションと虫歯の有無（p＝0.00），インパクションの深さと虫歯の形成（p＝0.004）には有意な相関が認められた．

RESULTS: A total of 626 radiographs were studied of which mesioangular impaction (35.3%) was the most prominent type and followed by horizontal impaction, causing distal caries in second molars. The age group between 20-40 years and female gender had the higher prevalence of distal caries in second molar teeth. There was a significant correlation between gender and cavity existence (p=0.00), between impaction and existence of decay (p=0.00), and depth of impaction with cavity formation (p=0.004).

結論:

下顎第三大臼歯に罹患した患者の31.8％が第二大臼歯に遠位歯頸部齲蝕を有していた．第三大臼歯の罹患による第二大臼歯の遠位う蝕に関連する要因としては，Mesioangular type，女性の性別，type Aが顕著であった．

CONCLUSIONS: A total of 31.8% of the patients with impacted mandibular third molars had distal cervical caries in second molars. Mesioangular type, female gender, type A were the prominent factors associated with distal caries in second molar teeth due to impacted third molars.