[Application of three-dimensional laser scanning-based maxillofacial soft tissue reconstruction in orthodontic treatment].

Objective: To establish a convenient and rapid method for constructing a digital model of the maxillofacial soft tissue based on three-dimensional laser surface scanning to allow direct and accurate observation of the soft tissue changes in the course of orthodontic treatment.

Methods: The point cloud data of three-dimensional laser scanning of the maxillofacial region were acquired from a healthy woman with Angle Class I occlusion, who maintained a horizontal Frankfort plane during scanning with the scanner placed at a distance of 80 cm. The scanning was repeated twice after wearing the dental cast for an Angle Class I occlusion. The three-dimensional digital model of the maxillofacial soft tissue was constructed based on the point cloud using GeoMagic10.0 software.

Results: The high-resolution three-dimensional model of the maxillofacial soft tissue reconstructed allowed accurate observation of the distinct facial anatomical landmarks and represented directly the soft tissue changes in the process of orthodontic treatment by merging the models. Using the analytic tool provided by the software, this model also allowed direct quantitative measurement of the nasolabial angle and the distances from the esthetic plane to the upper lip, labral inferior, and mentolabial sulcus, which were 111.86°, -3.57 mm, -2.54 mm, and 3.95 mm before orthodontic treatment as compared to 114.31°, -2.73 mm, -1.06 mm, and 3.46 mm during treatment, and 116.53°, -0.15 mm, 0.64 mm, and 3.11 mm after the treatment, respectively.

Conclusion: Three-dimensional laser surface scanning enables accurate and rapid construction of the digital model of the facial soft tissues, which may provide valuable assistance in orthodontic treatment.