6～16歳のクラスIII被験者の顎顔面成長

Craniofacial growth of Class III subjects six to sixteen years of age.

抄録

目的:

6～16歳の未治療の白人III級被験者の混合縦断的頭蓋顔面成長を特徴づけること。

OBJECTIVE: To characterize the mixed-longitudinal craniofacial growth of untreated, white, Class III subjects 6 to 16 years of age.

材料と方法:

III級不正咬合の女性19人と男性23人の連続セファログラムを3時点（6～8歳、10～12歳、14～16歳）で評価した。同数のI級対照者を無作為に選び、年齢と性別をマッチさせた。セファログラムをトレースしてデジタル化し、20の変数を評価した。成長パターンが定量化され、階級差と性差がマルチレベル分析を用いて評価された。

MATERIALS AND METHODS: Serial cephalograms of 19 females and 23 males with Class III malocclusion were evaluated at three time points (6-8, 10-12, and 14-16 years of age). A similar number of Class I controls were randomly selected and matched for age and sex. The cephalograms were traced and digitized, and 20 variables were evaluated. Growth patterns were quantified, and class and sex differences were evaluated using multi-level analyses.

結果:

クラスIの被験者と比較すると、クラスIIIの被験者は下顎平面角、歯肉角、下顎突出部の高さ、下顎コーパスの長さ、SNB角が有意に大きく（P≦0.05）、その差は6～16歳の間維持された。上顎の長さとANB角は、クラスIの被験者よりもクラスIIIの被験者の方が有意に小さく、その後も小さいままであった。下顔面高、上顎下顎差、下顎体長もIII級で有意に大きく、6～16歳の間に有意に増加した。WITS評価値はIII級被験者で有意に小さく、時間の経過とともに有意に減少した。ほとんどの直線的測定では、男性に有利な有意な性差が認められたが、角度的測定と上顎顎骨の前後関係（AP）では性差は認められなかった。

RESULTS: In comparison with Class I subjects, Class III subjects had significantly (P ≤ .05) larger mandibular plane angles, gonial angles, mandibular ramus heights, mandibular corpus lengths, and SNB angles, with differences that were maintained between 6 and 16 years of age. Maxillary lengths and ANB angles were significantly smaller and remained smaller in Class III subjects than in Class I subjects. Lower face height, maxillary-mandibular differential, and mandibular body length were also significantly larger and increased significantly more between 6 and 16 years of age in Class III subjects. The WITS appraisal was significantly smaller in Class III subjects and decreased significantly more over time. Most linear measures showed significant sex differences favoring males; the angular measures and anteroposterior (AP) maxillomandibular relationships showed no sex differences.

結論:

III級被験者のAP上顎顎骨関係は、時間の経過とともに悪化する。APの不一致は主に下顎の過度な成長によるもので、突出した過乖離の表現型を生じる。男性のAP不一致は女性のそれよりも大きく、その差は時間の経過とともに増大する。

CONCLUSIONS: The AP maxillomandibular relationship of Class III subjects worsens over time. AP discrepancies are primarily due to excessive mandibular growth, which produces a protrusive, hyperdivergent phenotype. The AP discrepancies of males are larger than those of females, with differences increasing over time.