下顎第三大臼歯の歯根破折の素因を検討した

Study the predisposing factors of root resorption during orthodontic uprighting treatment of impacted mandibular third molars.

抄録

目的:

下顎第三大臼歯の歯根破折の程度について検討する。

OBJECTIVE: To analyse the amount of root resorption of mesially or horizontally impacted mandibular third molars after orthodontic uprighting treatment.

材料と方法:

中・水平咬合で歯根が完全に形成された下顎第三大臼歯の患者24名（20～26歳）を対象とした。また、同側の下顎第一大臼歯が崩壊または欠損している患者を選択した。下顎第三大臼歯を立毛し、抜歯腔を閉鎖した。歯根吸収はpaired t-testで比較した。歯根吸収に関連する危険因子はピアソン相関分析で比較した。

MATERIALS AND METHODS: Twenty-four patients with an age range of 20∼26years old who had mesially/horizontally impacted third molars with complete root formation. And those with decayed or missing the mandibular first molar on the same side were selected. The lower third molars were uprighted and the extraction spaces closed. Root resorption was compared with paired t-test. The related risk factors for root resorption were compared with Pearson correlation analysis.

結果:

平均歯根吸収期間は10.00ヶ月（4～16ヶ月）であった。その結果、すべての埋伏第三大臼歯は治療後満足のいく結果を得た。治療終了時に下顎第三大臼歯の根の長さの短縮が認められたが、統計学的に有意な差は認められなかった（P<0.05）。歯根吸収は、アップライトの期間および歯根の移動距離と相関していた。

RESULT: The average uprighting time was 10.00 months (4∼16months). The study showed that all the impacted third molars were uprighted and got satisfactory outcomes after treatment. Shortening in length of mandibular third molar roots was detected at the end of the treatment, but no statistically significant differences were found (P<0.05). Root resorption was correlated with the duration of uprighting and the distance that root moved.

結論:

衝撃を受けた下顎第三大臼歯はアップライトされ、治療後の第三大臼歯の歯根吸収量は増加しなかった。歯根吸収の程度に影響するのは、アップライトの期間と歯根の移動距離である。

CONCLUSION: Impacted mandibular third molars were uprighted and the amount of root resorption of third molar after treatment was not increased. The duration of uprighting and the distance that root moved influence the degree of root resorption.