Fogorvosi szemle, 2021 (114. évfolyam, 1-4. szám)
2021-12-01 / 4. szám
FOGORVOSI SZEMLE 114. évf. 4. sz. 2021. n 169 Materials and Methods Study Sample This prospective study was approved by the Human Investigation Review Board, the University of Szeged, Albert Szent-Györgyi Clinical Centre (No. 151/2019-SZTE). Informed consent was obtained from all patients who agreed to participate in this study. Patients with skeletal class III malocclusion requiring bimaxillary surgery as the second step of their full comprehensive orthodontic-orthognathic treatment were recruited from the Craniofacial Unit, Department of Oral and Maxillofacial Surgery, Albert Szent-Györgyi Clinical Centre, University of Szeged, Hungary. Exclusion criteria were cleft lip and palate, craniofacial syndromes, major medical diseases, a history of facial trauma, and a previous orthognathic surgery. All of patients were of Caucasian ethnic backgrounds, had no further growth anticipated, and had had the pre-and post-surgical orthodontic treatments successfully completed (Figure 1) . Our study consisted of 12 patients (6 males and 6 females) with a mean age of 22 ± 2.17 years, range 19.6– 24.5 and without severe facial asymmetry (less than 4 mm of chin deviation from the mid-sagittal plane or facial midline). [13 , 42 ]. The sample size was determined based on the findings of a previous study by Koerich and colleagues [26 ]. All patients were treated by the same surgeon (J. P.), who performed maxillary advancement and a mandibular setback to achieving a normal dento-skeletal relationship. Following implementation of the treatment plan, the level of achieved skeletal movement was 3.87 ± 1.6 mm for the maxillary advancement, and 3.46 ± 1.34 mm for the mandibular setback. No additional surgical procedures such as genioplasty, rhinoplasty, or infraorbital augmentations were performed either, in conjunction with the osteotomies or postoperatively. Surgical Protocol The surgical procedure consisted of the conventional Le Fort I osteotomy and the Bilateral sagittal split setback osteotomy (BSSO). As per Obwegeser, the Le Fort I osteotomy cut was made above the apices of the maxillary teeth and underneath the infraorbital nerve [35 ], and then extended to achieve a full mobilization of the maxilla. The mobilized maxilla was moved and fixed in a previously planned position using a surgical splint. During the (BSSO), the subperiosteal incision was made. The osteotomy was performed according to Obwegeser/Dal Pont [15 ]: splitting of the mandible was carried out, and a segment of bone was removed to retract the body of the mandible guided by the fabricated surgical splint. All patients underwent internal fixation of the maxilla and the mandible with functional mini-plates and mini-screws, and a surgical wafer was placed for approximately 5-6 weeks after surgery. Following removal of the surgical wafers, intermaxillary elastic fixations were performed to stabilize the occlusion. Data processing and measurements 3D facial images using the 3D handheld structured-light scanner (Artec EvaTM ; Artec Group, Luxembourg) were obtained one week prior to the surgery (T0 ), and thereaf ter, 6 months post-surgery (T1 ). This scanner uses struc tured light scanning technique for precise capture of up to 16 frames per second in a point-and-shoot mode with every frame captured as a 3D image. The frames are adjusted automatically, real-time and deliver high resolution (up to 0.5 mm) and high accuracy (up to 0.1 mm). All images were taken with the head in a natural position, teeth within centric occlusion, lips in rest, and slightly closed eyes [39 ]. To accomplish the natural head balance, the subjects were seated in a back-supported and a vertically adjustable chair. They were instructed to turn their heads forward and backward with decreasing amplitude until a relaxed position is achieved [43 ]; then, they were requested to look straight ahead to the point on the wall in front of them at the eye level. During scanning, a hairband was used to prevent the concealment of the facial regions by the subjects’ hair. 19 landmarks, 5 bilateral and 9 unilateral (Table 1, Figure 2), were located according to the literature [ 27 , 40 ]; 13 linear and 6 angular measurements were taken directly with the 3D-facial images using Artec Studio V.12 software (Figure 3, 4) . To perform the 3D deviation analysis, the images were transferred into reverse engineering software (GOM Inspect Evaluation Software, Capture 3D, Inc., Santa Ana, CA); then, polygon meshes were created in stereolithography (STL) format. The hair, the ears, and the below-neck region were removed. The images obtained at the T0 time point were aligned with the images taken at T1 by using the overall best-fit method as per Dindaroglu and colleagues [16 ] (Figure 5) . Negative values indicate that T1 images are located behind the T0 images (blue shades), whereas positive values indicate that T1 images are located in front of the T0 images (red shades). To create morphological re gions, reference lines passing through different points specified on the face were determined and a 3D deviation analysis was performed in seven morphological regions of the face [16 ] (Table 2, Figure 6) . In addition, we calculated the deviation magnitude for the facial soft tissue landmarks directly on the 3D inspected meshes (Figure 7). Statistical Analysis Normal distribution of the data was set up through the Shapiro–Wilk and Kolmogorov-Smirnov tests. To determine the method’s reliability, T0 and T 1 images of the
