下顎第三大臼歯による第二大臼歯外側根吸収の有病率：CBCTによる研究

Prevalence of second molar external root resorption caused by mandibular third molars: a CBCT study.

抄録

本研究の目的は、コーンビームCT（CBCT）スキャンを用いて、下顎第三大臼歯の打撃による第二大臼歯の外歯根吸収（ERR）の有病率を評価し、PellとGregoryが提案した分類システムおよびWinterが提案した2つの分類システムを用いてERRの位置および重症度を第三大臼歯位置と関連づけることである。この横断的研究では，2人の較正された観察者が合計107枚のCBCTスキャンを評価した（女性71人，男性36人）．ERRの有無を判定した後、ERRをその位置（歯頸部、中間部、先端3分の1、根尖部）と重症度（軽度、中度、重度の吸収）により分類した。データは，ピアソン・カイ二乗検定，線形傾向のカイ二乗検定，ポアソン回帰分析で評価した．有意水準はP < 0.05とした．サンプル全体における第二大臼歯ERRの有病率は47.7％（n＝51）であった。男性患者の有病率は69.4％と有意に高かった（P = 0.002; Pearson chi-square test）。ERRが第二大臼歯に影響を及ぼす確率は、第三大臼歯がPell and Gregory class ICポジションの場合1.71倍（95％CI、1.27-2.31）、第三大臼歯がWinter mesioangularポジションの場合1.64倍（95％CI、1.38-1.95）であった。ERRの位置と重症度には統計的に有意な関連があり、頸部第三臼歯は軽度のERRで最も影響を受け、中間第三臼歯は重度のERRで最も影響を受けた。第三大臼歯の打撃による下顎第二大臼歯ERRの有病率は高く，特に男性患者において顕著であった．下顎第3大臼歯がPell and Gregory class IC位置またはWinter mesioangular位置にある場合、隣接する第2大臼歯のERRを引き起こす可能性が高いことが示された。

The aims of this study were to use cone beam computed tomographic (CBCT) scans to assess the prevalence of second molar external root resorption (ERR) caused by impacted mandibular third molars and to associate the location and severity of ERR with the third molar position using 2 classification systems-1 proposed by Pell and Gregory and the other proposed by Winter. In this cross-sectional study, 2 calibrated observers evaluated a total of 107 CBCT scans (71 female and 36 male patients). After the presence or absence of ERR was determined, ERR was classified according to its location (cervical, middle, apical third, or root apex) and severity (mild, moderate, or severe resorption). The data were assessed with the Pearson chi-square test, the chi-square test for linear trend, and Poisson regression analysis. The significance level was set at P < 0.05. The prevalence of second molar ERR in the sample as a whole was 47.7% (n = 51). The prevalence was significantly higher (69.4%) for male patients (P = 0.002; Pearson chi-square test). The probability that ERR would affect the second molar was 1.71 times greater when the third molar exhibited the Pell and Gregory class IC position (95% CI, 1.27-2.31) and 1.64 times greater when the third molar exhibited the Winter mesioangular position (95% CI, 1.38-1.95). There was a statistically significant association between ERR location and severity; the cervical third was the most affected by mild ERR and the middle third was the most affected by severe ERR. The prevalence of mandibular second molar ERR caused by impacted third molars is high, especially in male patients. Mandibular third molars in the Pell and Gregory class IC position or Winter mesioangular position demonstrated greater potential to result in ERR of the adjacent second molar.