矯正補助治療中の間接アンカー歯のアンカレッジロス評価

Anchorage loss assessment of the indirect anchor tooth during adjunctive orthodontic treatment.

抄録

はじめに:

本研究では、ミニスクリューに連結したアンカー歯（間接アンカー歯）の動揺を定量的に評価し、矯正補助治療中の動揺に影響する因子を検討した。

INTRODUCTION: This study quantitatively assessed movement of anchor teeth connected to a miniscrew (indirect anchor tooth) and investigated factors affecting movement during adjunctive orthodontic treatment.

方法:

片側にインダイレクトアンカーを装着した患者28名の治療前後の石膏模型を採取した。その模型をデジタルスキャンし、間接アンカー歯（実験群；n=52）と未治療歯（対照群；矯正力を加えない間接アンカー歯に対向する第一小臼歯と第二小臼歯；n=55）の2群とした。治療前と治療後のモデルを重ね合わせ，単変量線形混合モデルを用いて間接アンカー歯の移動量と移動方向を評価した．また、間接アンカー歯の移動に影響を及ぼす可能性のある因子とその有意性を多重線形混合モデルを用いて評価した。

METHODS: Dental plaster models of 28 patients whose treatment included an indirect anchor tooth on one side were collected before and after treatment. The casts were digitally scanned, and 2 groups were constituted: the indirect anchor teeth (experimental group; n = 52) and the untreated teeth (control group; the first and second premolars opposing the indirect anchor tooth to which no orthodontic force was applied; n = 55). Pretreatment and posttreatment models were superimposed and the amount and direction of indirect anchor tooth movement were evaluated with the use of a univariate linear mixed model. Possible factors affecting movement of the indirect anchor tooth and its significance were also evaluated with the use of a multiple linear mixed model.

結果:

間接アンカー歯は0.91±0.50mm移動し、横方向、縦方向、矢状方向に有意差は認められなかった。間接アンカー歯の位置は移動量に影響し、下顎では上顎よりも有意に移動量が多かった。

RESULTS: The indirect anchor tooth moved 0.91 ± 0.50 mm and did not exhibit significant differences in the transverse, vertical, or sagittal directions. The location of the indirect anchor tooth affected movement and the tooth moved significantly more in the mandible than in the maxilla.

結論:

間接支台歯は、補助矯正治療中に移動する可能性があるため、咬合変化を注意深く観察する必要がある。

CONCLUSIONS: The indirect anchor tooth can move during adjunctive orthodontic treatment and thus requires careful monitoring for occlusal changes.