Three–dimensional analysis of lip and cheek movements during smile in patients with unilateral lip and cleft palate

松本歯科大学大学院歯学独立研究科博士（歯学）学位申請論文;硬組織疾患制御再建学講座（主指導教員:各務　秀明教授

Three-dimensional analysis of lip and cheek movements during smile in patients with unilateral lip and cleft palate

【目的】唇顎口蓋裂患者の口唇形成術後の静的な顔貌については様々な解析が行われ、形態の改善が示されている。しかし、スマイル時の口唇の動きについては不明な点が多い。そこで片側性唇顎口蓋裂患者の口唇形成術後のスマイル時の口唇および頬部の三次元的移動様相について検討した。【資料及び方法】松本歯科大学病院矯正歯科を受診した口唇形成術後の片側性唇顎口蓋裂男児11名（平均年齢5.2歳、右側唇顎口蓋裂8名、左側唇顎口蓋裂3名、平均オーバージェット－2.0mm、平均オーバーバイト+1.9mm）を対象とした。頭部固定は行わず、安静時とスマイル時の写真をステレオカメラで撮影した。三次元解析ソフトウェア（QM-3000）を用いて、口角、頬部および上下唇中央の三次元的移動距離を計測し、患側と健側の移動量を、Wilcoxon検定を用いて比較検討した。また、正面顔面形態とスマイル時の口唇運動の関連を検討するために、スマイル時の三次元方向の移動距離と正面セファログラムの測定項目の距離を、Spearmanの相関係数を用いて検定した。なお、本研究は松本歯科大学研究等倫理審査委員会にて承認されている（許可番号第0252号）。【結果】スマイル時に、患側口角と健側口角は、それぞれ外側に4.69mm、2.67mm、上方に4.53mm、3.00mm、後方に4.35mm、3.02mm移動し、いずれも患側が健側と比べ有意に大きい値を示した。一方、頬部は患側と健側の移動距離に有意差はなかった。上唇中央部と下唇中央部では、垂直方向で、それぞれ上方に2.21mm、下方に6.60mm移動し、有意差を示した。口唇と頬部の三次元移動量と正面顔面形態の関連は、下顎骨幅差（患側-健側）とMe偏位量は口角水平方向の移動量差（患側-健側）と有意な正の相関を示し、上顎骨高差（患側-健側）と下顎骨高差（患側-健側）は口角垂直方向移動量差（患側-健側）と有意な負の相関を示した。【考察】口唇裂は手術後に上唇の形態は修復されるが、瘢痕組織を形成する。スマイル時には、口輪筋を停止部として大頬骨筋、口角挙筋などが収縮する。その際に、片側性唇顎口蓋裂患者では、大頬骨筋等で口角を牽引する際に、上唇の瘢痕組織が上唇中央より患側よりに位置するため口角部で口輪筋の抵抗力は患側が健側より小さくなり、患側口角が上外後方へ大きく移動したと推察された。スマイルと正面顔面形態の関連では下顎骨の偏位量が大きいほど、スマイル時に患側口角が健側口角に比べより外方に移動し、患側の上顎骨、下顎骨の高さが健側に比べ小さいほど、スマイル時に口角患側が健側口角に比べ、より上方に移動した。すなわち、下顎骨偏位量が大きいほど、スマイル時に口唇の非対称性が悪化することが示された。正面顔面形態で下顎骨偏位が大きく、患側上顎骨の高さが健側に比べ上方に位置する程、上唇の瘢痕部も患側上方に位置する。 この上唇瘢痕部の位置の違いから、スマイル時に患側口角が健側口角に比べ大頬骨筋、口角挙筋などに牽引され非対称がさらに悪化した可能性が考えられた。2020博士（歯学）松本歯科大

A preliminary study of soft tissue movements during smiling in patients with mandibular protrusion with mandibular deviation before and after surgical orthodontic treatment

We investigated the changes in lip and cheek movements involved in smiling, recorded before and after surgical orthodontic treatment for mandibular protrusion with mandibular deviation (MPD), and compared the obtained data with those of individuals with normal occlusion (NO). The study enrolled 8 individuals with NO and 8 patients with MPD who underwent surgical orthodontic treatment at the Matsumoto Dental University Hospital. The lip and cheek movements of individuals were analyzed three–dimensionally using stereo images, and their frontal and lateral craniofacial morphologies were assessed using posterior–anterior and lateral cephalograms. Pre–treatment assessment of lip movements in MPD patients showed that the corner of mouth (CM) on the non–deviated side exhibited a significant increase in upward move ment and decrease in lateral movement, as compared to the deviated side. However, the comparison of these results with those of individuals with NO revealed that the lateral and posterior movement of the CM on the non–deviated and deviated sides, respectively, was significantly lesser in patients with MPD than in individuals with NO. Post–treatment assessment of lip movements showed an increase in the lateral and the upward movement of the CM on the non–deviated and deviated side, respectively, indicating the successful correction of asymmetrical CM movement. However, the posterior movement in the CM on the deviated and non–deviated sides in the patients with MPD were significantly lesser than those in individuals with NO. Furthermore, a comparison of the absolute values of three–dimensional movements recorded between the center of the upper and lower lips revealed no significant difference in pre– and post–treatment movements. On the contrary, post–treatment movement of the center of the lower lip in the posterior direction was significantly lesser in patients with MDP than individuals with NO. The three–dimensional movement of the cheek did not show significant difference between the deviated and non–deviated sides before and after treatment. However, the anterior movement of the cheek on the non–deviated side in the individuals with MPD increased significantly after treatment. There were no significant differences in the three–dimensional movement of cheek among individuals with MPD, before and after treatment, and in the individuals with NO. In the present study, the asymmetrical three–dimensional movements of CM involved in smiling, between the deviated and non–deviated sides in the individuals with MPD, were corrected after surgical orthodontic treatment. However, the post–treatment movements in the individuals with MPD were different from those in individuals with NO

Cytokinin Signaling Is Essential for Organ Formation in Marchantia polymorpha

Cytokinins are known to regulate various physiological events in plants. Cytokinin signaling is mediated by the phosphorelay system, one of the most ancient mechanisms controlling hormonal pathways in plants. The liverwort Marchantia polymorpha possesses all components necessary for cytokinin signaling; however, whether they respond to cytokinins and how the signaling is fine-tuned remain largely unknown. Here, we report cytokinin function in Marchantia development and organ formation. Our measurement of cytokinin species revealed that cis-zeatin is the most abundant cytokinin in Marchantia. We reduced the endogenous cytokinin level by overexpressing the gene for cytokinin oxidase, MpCKX, which inactivates cytokinins, and generated overexpression and knockout lines for type-A (MpRRA) and type-B (MpRRB) response regulators to manipulate the signaling. The overexpression lines of MpCKX and MpRRA, and the knockout lines of MpRRB, shared phenotypes such as inhibition of gemma cup formation, enhanced rhizoid formation and hyponastic thallus growth. Conversely, the knockout lines of MpRRA produced more gemma cups and exhibited epinastic thallus growth. MpRRA expression was elevated by cytokinin treatment and reduced by knocking out MpRRB, suggesting that MpRRA is upregulated by the MpRRB-mediated cytokinin signaling, which is antagonized by MpRRA. Our findings indicate that when plants moved onto land they already deployed the negative feedback loop of cytokinin signaling, which has an indispensable role in organogenesis