様々なタイプの第三大臼歯転倒による下顎第二大臼歯の病態：比較臨床研究

Pathologies Associated with Second Mandibular Molar Due to Various Types of Impacted Third Molar: A Comparative Clinical Study.

抄録

はじめに:

第三大臼歯の埋伏は、第二大臼歯に様々な程度の障害をもたらす。考えられる合併症には、遠位頸部う蝕、第二大臼歯の歯根吸収、歯周病、歯原性嚢胞などが含まれる。特定の第三大臼歯が第二大臼歯に影響を及ぼすかどうかは、骨内での位置と方向によって決まる。

INTRODUCTION: Impacted third molars are associated with various degrees of damage to the second molars. The possible complications also include distal cervical caries, root resorption of second molar, periodontal problems, odontogenic cysts, etc. Whether a particular impacted third molar is going to affect second molar depends upon its position and orientation in the bone.

材料と方法:

本研究は418症例を対象とした。3人の検査者が臨床的およびX線写真的に患者を評価し、少なくとも2人の検査者が同意した症例のみを本研究に含めた。合計341症例（男性163症例、女性178症例）、年齢層（15～40歳）、下顎第3大臼歯に衝撃を受けた症例を対象とした。臨床的およびX線写真的に、下顎第3大臼歯および第2大臼歯の埋伏状況を評価した。同時に、第3大臼歯の埋伏による下顎第2大臼歯に関連する様々な病態（う蝕、歯周ポケット、歯根吸収）の有病率も評価し、様々な埋伏のタイプおよび位置で比較した。

MATERIALS AND METHOD: This study was carried out in 418 cases. Three examiners evaluated the patient clinically and radiographically and only those cases were included in this study where at least two observers agreed. A total of 341 cases (163 males and 178 female), age range (15-40 years) with impacted mandibular third molars, were included. Clinically and radiographically, the impacted mandibular third and second molars were evaluated; simultaneously, the prevalence of various pathologies associated with mandibular second molar (dental caries, periodontal pockets, root resorption) due to impacted third molar was also evaluated and compared among various types and positions of impactions.

結果:

統計分析は、ピアソン・カイ二乗およびAsymp.Sig.（両側）検定を用いた。中斜角嵌頓の有病率は最大であった（50.1％）。隣接下顎第二大臼歯の中顎角衝合およびポジションB（PellおよびGregory分類）は、う蝕と有意に関連しており（それぞれ32.20％および33.90％）、ポジションBの衝合（26.8％）｛水平（14.7％）、遠心角（12.10％）、垂直（14.5％）中顎角（16.4％）｝で歯周ポケットが多く認められた。歯根吸収は水平埋伏（17.30％）が最も多く、c位置（12.30％）であった。第三大臼歯の埋伏による第二大臼歯の病態は、う蝕（19.9％）＞歯周ポケット（15.2％）＞歯根吸収（8.5％）の順であった。

RESULTS: Statistical analysis was carried out using Pearson Chi-square and Asymp. Sig. (two-sided) test. Prevalence of mesioangular impactions was maximum (50.1%). Mesioangular impaction and position B (Pell and Gregory classification) were significantly associated with dental caries (32.20% and 33.90%, respectively), and periodontal pockets were seen higher with position B impactions (26.8%) {horizontal (14.7%), disto-angular (12.10%), vertical (14.5%) mesioangular (16.4%%)} in adjacent mandibular second molar. Root resorption was seen maximally in horizontal impaction (17.30%) with position c type (12.30%). The order of pathologies associated with second molar due to impacted third molar was dental caries (19.9%) > periodontal pockets (15.2%) > root resorption (8.5%).

考察:

第三大臼歯の嵌頓による第二大臼歯に関連する病態に関するエビデンスは、第三大臼歯の外科的除去の意思決定に役立つ。様々なタイプのimpactionとそれらに関連する病態の有病率は、特定のタイプが関連する病態の可能性が高いため、impacted toothの治療計画に役立つであろう。

DISCUSSION: Evidence regarding pathologies are associated with second molar due to impacted third molar aids in decision making for surgical removal of third molars. Different types of impaction and the prevalence of pathologies related to them would aid in treatment planning of the impacted tooth as certain types have high probability of pathologies associated.