第三大臼歯の下顎管への接近を予測する際のパノラマX線写真の信頼性。コーンビームコンピュータ断層撮影法による比較

Reliability of panoramic radiography in predicting proximity of third molars to the mandibular canal: A comparison using cone-beam computed tomography.

• Willy James Porto Nunes
• Aline Lisboa Vieira
• Letícia Drumond de Abreu Guimarães
• Carlos Eduardo Pinto de Alcântara
• Francielle Silvestre Verner
• Matheus Furtado de Carvalho

抄録

目的:

本研究の目的は，下顎第三大臼歯の根尖が下顎管に近接していることを予測するための7つのパノラマX線写真の徴候の信頼性を，コーンビームCTを用いて分析し，これらの知見をPell and GregoryおよびWinter分類システムと相関させることである。

Purpose: The purpose of this study was to analyze the reliability of 7 panoramic radiographic signs for predicting proximity of the root apices of mandibular third molars to the mandibular canal using cone-beam computed tomography and to correlate these findings with the Pell and Gregory and the Winter classification systems.

材料と方法:

両側の下顎第三大臼歯に衝撃を受けた74名の患者を対象に、観察的、横断的、記述的研究を行った。パノラマX線写真では，歯根部に4つの徴候（歯根端の暗色化，偏向，狭小化，歯根端の二分化）と，下顎管に3つの徴候（下顎管の分岐，狭小化，中断）が観察された。コーンビームCT画像を解析し，下顎管の破断，分岐，根尖の偏向を確認した。

Materials and Methods: An observational, cross-sectional, descriptive study was conducted on 74 patients with bilateral impacted mandibular third molars. Four panoramic radiographic signs were observed in the tooth root (darkening, deflection, and narrowing of the root apices, and bifid apices), and another 3 in the mandibular canal (diversion, narrowing, and interruption of the mandibular canal). Cone-beam computed tomography images were analyzed to identify disruption and diversion of the mandibular canal and root deflection.

結果:

二値ロジスティック回帰の結果、下顎第三大臼歯の根尖が下顎管に近接することを予測できたのは、7つのパノラマX線写真の徴候のうち、根の暗色化、根の偏向、根の狭小化、下顎管の中断の4つのみであった（<0.05）。

Results: Binary logistic regression showed that only 4 of the 7 panoramic radiographic signs were able to predict proximity of the root apices of the mandibular third molars to the mandibular canal: darkening of the root, deflection of the root, narrowing of the root, and interruption of the mandibular canal (<0.05).

結論:

パノラマX線写真において，歯根の暗化，偏向，狭小化と下顎管の途絶は，下顎第三大臼歯の抜歯を計画する際にコーンビームCTを行うべきであることを示している。下顎第三大臼歯と下顎管の近接性は，Winter分類と相関している。

Conclusion: Darkening, deflection, and narrowing of the root, in tandem with the interruption of the mandibular canal on panoramic radiographs, indicate that cone-beam computed tomography should be performed when planning the extraction of impacted mandibular third molars. Proximity between mandibular third molars and the mandibular canal is correlated with the Winter classification.

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