コーンビームCT画像における中口蓋縫合成熟段階による口蓋の形態学的特徴：横断的研究

Morphological characteristics of the palate according to mid-palatal suture maturational stage on cone-beam computed tomography images: A cross-sectional study.

抄録

はじめに:

中口蓋縫合成熟期以外にも、口蓋の形態はミニスクリュー挿入計画の有効性や口蓋拡張の有効性に関与する可能性がある。

INTRODUCTION: Besides the mid-palatal suture maturation stage, the morphology of the palate might also play a role in the effectiveness of miniscrew insertion planning or effectiveness of palatal expansion.

目的:

口蓋中隔縫合の成熟段階に応じた口蓋中隔の長さ、高さ、表面積、および口蓋横隔縫合の成熟度との相関を、結果的に選択された被験者グループのコーンビームCT（CBCT）上顎画像上で評価することを目的とした。

OBJECTIVES: The aim was to assess the mid-palate length, height and surface area according to the mid-palatal suture maturation stage and its correlation to the maturity of the transverse palatine suture on cone-beam computed tomography (CBCT) maxillary images in a consequently selected group of subjects.

材料と方法:

33.9±22.7歳の被験者100名（女性56名、男性44名）の高解像度CBCT画像を選択した。画像は中口蓋縫合成熟期（B期、C期、D期、E期）ごとに分類し、各期ごとに25枚の画像を収集した。切歯孔後縁から後鼻棘までの中口蓋の長さ、高さ（2mm間隔）、表面積を測定し、口蓋横縫合の成熟度を記録した。

MATERIAL AND METHODS: High-resolution CBCT images of 100 subjects (56 females, 44 males), aged 33.9±22.7 years, were selected. The images were clustered according to the mid-palatal suture maturation stage (stages B, C, D, and E) and 25 images per stage group were retrieved. The length, heights (at 2mm intervals) and surface area of the mid-palate were measured from the posterior border of the incisal foramen to the posterior nasal spine, and the maturity of the transverse palatine suture was recorded.

結果:

中口蓋の長さについては群間差はみられなかったが、高さと表面積は成熟期間で有意差がみられた。中口蓋の高さは、成熟期D群とE群（それぞれ5.65±1.55mmと5.77±1.70mm）では、B群とC群（それぞれ6.97±1.82mmと7.00±1.53mm）よりも有意に小さかった。しかし、その差は第6mm測定点より遠位でのみ有意であった。表面積は群間で有意差があり、D期およびE期（それぞれ1.53±0.38cmおよび1.57±0.54cm）に比べ、B期およびC期（それぞれ1.82±0.55cmおよび1.86±0.41cm）で高い値を示した。中口蓋全平均高、表面積と中口蓋縫合期との間には、有意な負の相関が見られたが、相関は乏しかった（それぞれrho=-0.278、P=0.005、rho=-0.222、P=0.027）。さらに、年齢と口蓋正中縫合期および口蓋横縫合期の成熟度との間には、それぞれ非常に強い正の相関から中程度の正の相関（rho=0.847、P<0.001、rho=0.739、P<0.001）が認められた。口蓋中隔縫合と口蓋横隔縫合の成熟期はともに正の相関があり、非常に強い相関を示した（rho=0.839, P<0.001）。

RESULTS: No between-stage-group differences were seen for mid-palate length, while heights and surface areas were significantly different between maturational stages. The mid-palate height was significantly smaller in maturational stages D and E groups (5.65±1.55mm and 5.77±1.70mm, respectively) than in groups B and C (6.97±1.82mm and 7.00±1.53mm, respectively). However, differences were significant only distally to the sixth mm measurement point. The surface area was significantly different among groups, denoting higher values for stage B and C (1.82±0.55cm and 1.86±0.41cm, respectively), compared to stage D and E groups (1.53±0.38cm and 1.57±0.54cm, respectively). A significant negative but poor correlation was seen between mid-palate total average height, surface area and mid-palatal suture stage (rho=-0.278, P=0.005 and rho=-0.222, P=0.027, respectively). Moreover, a very strong to moderate positive correlation (rho=0.847, P<0.001, rho=0.739, P<0.001) was seen between age and the maturational stage of the mid-palatal and transverse palatine sutures, respectively. Both the mid-palatal and transverse palatine sutures maturity stages were positively and very strongly correlated (rho=0.839, P<0.001).

結論:

中口蓋の高さと表面積は成熟段階群間で有意差が認められたが、中口蓋の長さに関しては差が認められなかった。成熟度の低い縫合糸は、成熟度の高い縫合糸よりも高さと表面積の値が大きい。この点に関してはさらなる研究が必要であるが、口蓋中隔縫合の成熟段階Cは、口蓋横断面の成熟段階に関してより大きな分布のばらつきを示し、これは骨格固定装置を使用しても、骨格的口蓋拡大が成功した場合と失敗した場合の識別因子となる可能性がある。

CONCLUSIONS: The height and surface area of the mid-palate were significantly different among the maturational stage groups, while no differences were observed regarding the mid-palate length. Less mature sutures exhibit greater height and surface area values than more mature sutures. Although further research is needed in this regard, the mid-palatal suture maturational stage C showed greater distribution variability in terms of the transverse palatal maturation stages, which might be a discriminating factor between successful and unsuccessful skeletal palatal expansion, even with the use of skeletal anchorage devices.