교정치과의사의 관점에서 본 안면비대칭의 수술적 치료와 제한

Abstract

To accurately assess facial asymmetry, it is critical to minimize errors associated with the evaluator’s method of estab lishing the Frankfort Horizontal plane, as well as inaccuracies in landmark identification caused by the patient’s head position. Realigning the head position using computer algorithms eliminates the need for traditional cephalometric points or reference planes, thereby reducing errors linked to evaluator variability and imprecise landmark identification. A reference plane that divides the mandible into left and right halves is required to create a mirror image of the man dible. By generating and superimposing this mirror image, the degree of asymmetry can be visually identified. Further more, the “Similarity Index” between the mirror image of the left mandible and the original right mandible image can be used to quantify symmetry. When mandibular asymmetry was examined in specific regions using this method, it was discovered that the anterior portion of the mandible had a higher similarity index after orthognathic surgery, indicating improved symmetry. The middle portion demonstrated high concordance before and after surgery, while the posterior portion exhibited a low similarity index even after surgery. Therefore, it can be concluded that improving the similar ity index of the anterior mandible is most important for enhancing mandibular asymmetry postoperatively, while the posterior region is less affected by surgery. The analysis using the “Tomographic Similarity Scan” protocol can detect inherent mandibular asymmetry and accurately delineate deformed regions of the mandible. This approach facilitates precise surgical planning and reduces residual asymmetry.