下顎第3大臼歯のインパクションの位置と隣接する第2大臼歯の歯・歯周病変の発生との関連性

THE RELATIONSHIP OF THE POSITION OF MANDIBULAR THIRD MOLAR IMPACTION WITH THE DEVELOPMENT OF DENTAL AND PERIODONTAL LESIONS IN ADJACENT SECOND MOLARS.

抄録

目的:

本研究の目的は、下顎第三大臼歯の埋伏歯の位置の違いが下顎第二大臼歯の歯・歯周病変に及ぼす影響を評価し、病変の重症度と患者の年齢との関連を検討することである。

OBJECTIVE: The aim of this study was to evaluate the effect of different positions of Mandibular third molar impaction teeth on dental and periodontal lesions of mandibular second molars and correlate the lesion severity with patient age.

材料と方法:

本レトロスペクティブ研究では、2017年から2021年の間に○○大学口腔顎顔面放射線科を受診した患者212名のCBCT画像を評価した。下顎第二大臼歯への第三大臼歯内反の歯周病変および歯性病変の影響を評価した。歯性病変は軽度、中等度、重度に分類したが、歯周病変は根の2/3を超えない症例を軽度、2/3を超える症例を重度に分類した。データの解析にはPearsonのカイ二乗検定，Mann-Whitney UまたはKruskal-Wallis検定を用いた．さらなる分析のために多変量ロジスティック回帰モデルを構築した。

MATERIALS AND METHODS: This retrospective study assessed 212 CBCT images of patients who visited the department of Oral and Maxillofacial radiology of XX university between 2017 and 2021. Periodontal and dental lesion effects of impacted third molars on mandibular second molars were evaluated. While dental lesions were classified as mild, moderate, and severe, periodontal lesions were classified as mild in cases not exceeding 2/3 of the root, and severe in cases exceeding 2/3 of the root. Pearson's chi-square tests, Mann-Whitney U or Kruskal-Wallis test were used for data analsis. A multivariate logistic regression model was constructed for further analysis.

結果:

歯周病変は第3大臼歯に隣接する第2大臼歯に多く認められ（157歯、74.1％）、10％に歯性病変が認められた。第3大臼歯の位置のうち、中斜位は歯周病変の有病率が高く（88％）（p<0.001）、次いで水平位（71％）であった。歯周病変は、30～39歳および40歳以上の症例で、20歳未満および21～24歳の症例よりも重度であった。歯周病変の重症度を増加させる可能性は、中斜位、水平位、垂直位/逆位の方が低い。(OR=0.02、p<0.001、OR=0.28、p=0.008、OR=0.14、p<0.001）結論：第三大臼歯は中切角に埋伏していることが多く、この位置は第二大臼歯の歯周感染リスクを最も高める。CBCTは、第三大臼歯の位置と第二大臼歯との関係を評価できる信頼性の高い画像診断法である。

RESULTS: Periodontal lesions were frequently observed in the second molar adjacent to the third molar (157 teeth, 74.1%), dental lesions were observed in 10%. Among the third molar positions, the mesioangular position was associated with a high (88%) prevalence of periodontal lesions (p<0.001), followed by the horizontal position (71%). The periodontal lesion was more severe in cases 30-39 years old and over 40 years old than in cases under 20 years old and 21-24 years old. Distoangular, horizontal and vertical/inverse positions are less likely to increase the severity of the periodontal lesion than the mesioangular position. (OR = 0.02; p <0.001, OR = 0.28; p =0.008, OR = 0.14; p <0.001,respectively) CONCLUSIONS: The third molars are often impacted in the mesioangular position, and this position most increases the risk of periodontal infection in the second molars. Accurate diagnosis and evaluation can minimize complications, and CBCT is a reliable imaging technique in which the position of the third molars and their relationship with the 2nd molars can be evaluated.