開咬患者における歯根冠比率と咬合接触喪失および高下顎平面角との関係

Relationships between the root-crown ratio and the loss of occlusal contact and high mandibular plane angle in patients with open bite.

抄録

目的:

開咬患者の歯根冠長比（R/C）および歯根長を測定し、咬合接触（OC）および下顎平面（Mp）角との関係を検討する。

OBJECTIVE: To determine the root-crown (R/C) ratio and dental root length of teeth in patients with open bite and seek any relationships with occlusal contact (OC) and the mandibular plane (Mp) angle.

材料と方法:

少なくとも4本の前歯が負の過蓋咬合を有する開咬患者31名と、臨床的に正常なオーバージェットと過蓋咬合を有するコントロール患者31名を登録した。R/C比、歯根長、OC、Mp角はそれぞれパノラマX線写真、歯型、セファログラムを用いて測定した。グループ間の平均差、開咬患者におけるR/C比、歯根長、Mp角の変化を統計的に分析した。

MATERIALS AND METHODS: Thirty-one patients with open bite with negative overbite of at least four anterior teeth and 31 control patients with clinically normal overjet and overbite were enrolled. R/C ratios, dental root length, OC, and Mp angle were measured using panoramic radiographs, dental casts, and cephalograms, respectively. Mean differences between the groups, and variations between the R/C ratio or root length and Mp angle in patients with open bite were statistically analyzed.

結果:

切歯から小臼歯にかけてのR/C比およびOC比は、開咬患者の方がコントロール群よりも有意に低く、歯根が短い歯もあった。開咬患者では、低いR/C比や歯根長と高いMp角の関係が有意であった。

RESULTS: R/C and OC ratios from the incisors to premolars were significantly lower for patients with open bite than for controls, and some teeth had short dental roots. Relationships between low R/C ratio or root length and high Mp angle were significant in patients with open bite.

結論:

開咬患者、特にMp角が高い患者では、R/C比が悪く、歯根が短い歯があり、OCの喪失に関係している可能性がある。

CONCLUSION: Patients with open bite, especially those with a high Mp angle, have an unfavorable R/C ratio and short dental roots in some teeth, which may be related to the loss of OC.