垂直歯根破折の発生における咬合因子の役割

[The role of occlusal factors in the occurrence of vertical root fracture].

抄録

目的:

垂直歯根破折患者の咬合特性および歯の摩耗状態を調査し，垂直歯根破折の病因および咬合障害，歯の摩耗と臼歯の垂直歯根破折との関係について考察する。

PURPOSE: To investigate the occlusal characteristics and the condition of tooth abrasion in patients with vertical root fracture and to discuss the etiology of the vertical root fracture and the relationships between occlusal disorder, tooth abrasion and vertical root fracture of molars.

研究方法:

227例の歯根破折患者を対象とし，関与する歯は309本であった。歯周状態，咬合摩耗量，咬合接触面積，咬合干渉，咬合外傷，X線フィルムを観察し，評価した．すべての統計解析は，SPSS13.0ソフトウェアパッケージを用いて行った。グループ間の差は，SPSS13.0ソフトウェアパッケージを用いたX(2)検定で比較しました，また，日付はn(%)で表しました。

METHODS: Two hundred and seventy-seven cases of root fracture patients were included in the study, with 309 involved teeth. The periodontal status, occlusal wear, occlusal contact area, occlusal interference, occlusal trauma and the X-ray film were observed and evaluated. All statistical analyses were performed using SPSS13.0 software package. Date was expressed as n(%).Differences between groups were compared using X(2) test with SPSS 13.0 software package.

結果:

垂直歯根破折は40歳から60歳の患者に発生し，第一大臼歯の中歯根または頬側歯根に多く発生していた．歯周組織の破壊は垂直破折のない歯根に比べて有意に大きく，局所的に歯周ポケットが形成されていた．罹患歯には，重度の咬合面摩耗，高くて急なノンワークチップ，ワーキングチップの摩耗，深い咬合面の凹み，ディスタルエッジの低下が認められた．垂直的歯根破折の程度は，深い咬合面の凹みの部位と関連していた．垂直歯根破折の程度は咬合面の深い凹みの部位に関連しており，咬合干渉や咬合性外傷が垂直歯根破折の素因となっていた．

RESULTS: Vertical root fracture occurred in patients aging 40 to 60 years, the first molar mesial root or buccal root was mostly involved. Periodontal tissue destruction was significantly greater than roots without vertical fracture, with formation of localized periodontal pocket. Severe occlusal surface wear, high and steep non-work tip, working tip abrasion, deep occlusal surface concave and lower distal edge were seen in the affected teeth.The degree of vertical root fracture was related to the site of deep occlusal surface concave. Occlusal interference or occlusal trauma was the predisposing factors of vertical root fracture.

おわりに:

垂直歯根破折は，不正咬合や歯の摩耗と関連する．咬合の変化は過大な咬合力と異常な咬合力の方向性をもたらし，垂直歯根破折の重要な要因となると考えられた．

CONCLUSIONS: Vertical root fracture is associated with malocclusion and tooth abrasion. Changes of occlusion leads to over occlusal force and abnormal direction of occlusal force, which may be important factor of vertical root fracture.