领域：学术论文 · 自然科学

For the facemask miniplate protocol, 2 anchor surgical miniplates (55-0851; Stryker Leibinger, Freiburg, Germany) were placed 1 at each zygomatic buttress area. Surgical miniplates were adapted and bent according to the anatomy of the zygomatic buttress in a curvilinear pattern according to the anatomic shape of the zygomatic buttress area and fixed with 3 self-tapping bone screws per side (2-mm diameter, 6-mm length; 50-20706; Stryker Leibinger). The distal end of the miniplate was exposed through the keratinized attached gingiva near the canine to prevent gingival irritation, and the end holes of the miniplates were cut to create hooks for elastics. Three weeks after the surgery, an orthopedic force of 400 to 500 g per side was applied by heavy extraoral elastics directed 30 downward and forward from the occlusal plane from the miniplates to the facemasks. The patients were asked to replace the elastics once each day. A removable maxillary biteplate covering the posterior occlusal surfaces was placed to eliminate occlusal interference in the incisor region until correction of the anterior crossbite was obtained. For the Class III elastics and miniplate protocol, 4 straight miniplates (55-0851; Stryker Leibinger) were placed. In the maxilla, straight surgical miniplates, 25 mm or 6 holes in length, were adapted to the anatomy of the infrazygomatic buttress and fixed with 3 selftapping bone screws per side (2-mm diameter, 6-mm length; 50-20706; Stryker Leibinger). In the mandible, straight miniplates of 21 mm or 5 holes in length were adapted to the bone anatomy inferiorly between the mandibular lateral incisors and canines and fixed with 2 or 3 self-tapping bone screws per side so that the upper screw was at the level of root apices. All mucoperiosteal flaps were secured and sutured, exposing the ends of the miniplates over the keratinized attached gingiva to prevent gingival irritation. The distal end holes of the miniplates were cut to create hooks for elastics.
Three weeks after the surgery, the miniplates were loaded with Class III elastics on each side to provide a force of approximately 250 g to each side. The patients were instructed to wear the elastics 24 hours per day. The elastics were replaced at least once each day. A removable biteplate covering the occlusal surface of maxillary teeth was placed to eliminate occlusal interference in the incisor region until correction of the anterior crossbite was obtained . The decision to discontinue orthopedic treatment in groups 1 and 2 was made by the operator when the patients had 3 to 4 mm of positive anterior overjet. For each patient, a lateral cephalogram and facial moulage were obtained before treatment (T1) and at the end of protraction therapy or the observation period (T2), All facial moulages were scanned with the Facial Insight 3D Scanner (Motion View Software, Chattanooga, Tenn). Hence, 3D photographs of all patients and controls were acquired. All subjects were in centric occlusion, with relaxed facial musculature and lips. The 3D photographs were imported in stereolithography binary file format (*.stl) into an advanced processing software package (Geomagic Control 14; Geomagic, Research Triangle Park, NC) for further analysis. All 3D photographs were acquired in a similar way and had the same orientation. The facial soft tissue changes after maxillary protraction were evaluated by superimposition of the T1 and T2 3D photographs for every patient by a surface-based registration, Maal et al concluded that surface-based registration is an accurate method to compare 3D photographs of the same subject at different times rather than reference frame-based registration.
For the initial register of T1 and T2 scans, 9 markers were used as references to superimpose the images: (1) left endocanthion, (2) left exocanthion, (3) right  endocanthion, (4) right exocanthion, (5) soft tissue nasion, (6) left palpebrale superius, (7) left palpebrale inferius, (8) right palpebrale superius, and (9) right palpebrale inferius.20-22 The 3D photographs at T1 were set as fixed, and the T2 3D photographs were set as floating objects. For more refining of the superimpositions, the final register was made on the wide surface starting from right and left exocanthion and extending upward over all the forehead on the area that would not be influenced by the treatment. The T1 and T2 3D images were superimposed with the same coordinate system .23 For the 3D analysis of each subject, the T1 face scan was set as a reference, and the T2 scan was set as the test, and then the 3D compare analysis was performed. The 3D compare analysis generated a 3D color-coded map that displayed the areas and magnitudes of changes in facial soft tissues between the T1 (reference) and T2 (test) scans . Soft tissue landmarks, including right and left buccale points, right and left points of the cheek, subnasale, labiale superius, labiale inferius, soft tissue B-point, soft tissue pogonion, and soft tissue menton, were defined using the Create Annotation function in the Geomagic Control 14 software.21,22 The Annotation function measured the magnitude of deviation between the T1 and T2 scans at the selected points corresponding to x-, y-, and z-axes (Dx, deviation in the transverse direction; Dy, deviation in the vertical direction; Dz, deviation in the anteroposterior direction). The magnitudes of deviations were analyzed statistically. Cephalometric radiographs were obtained at T1 and T2 for all subjects to evaluate the amounts of maxillary advancement and the changes. Hence, the soft tissue changes were compared with actual skeletal movements. All cephalometric radiographs were scanned and analyzed by 1 investigator (M.H.E) using software (version 11.7; Dolphin Imaging and Management Solutions, Chatsworth, Calif). The analysis consisted of the following.
Skeletally anchored maxillary protraction using miniplates was introduced to transfer the orthopedic forces directly to the maxilla, to achieve an outcome not possible by conventional tooth-anchored facemask therapy in which a large portion of the force is dissipated to the periodontal ligament area. The application of orthopedic force through the teeth results in unwanted dentoalveolar changes such as extrusion and mesial movement of the maxillary molars, proclination of the maxillary incisors, and retroclination of the mandibular incisors. Moreover, studies have shown that facemask and rapid maxillary expansion therapies produce greater dental than skeletal changes; in contrast, bone-anchored maxillary protraction produces greater skeletal changes and open circummaxillary sutures. This is the first study to use a 3D approach to evaluate the facial soft tissue changes associated with skeletally anchored maxillary protraction protocols: skeletally anchored facemask with miniplates, and Class III elastics from infrazygomatic miniplates in the maxilla to symphyseal miniplates in the mandible. The conventional lateral cephalometric analysis evaluates the soft tissue changes only at the midsagittal area. However, patients usually evaluate their own soft tissue esthetics on the basis of how they look in the frontal view. Therefore, imaging methods, such as 3D computed tomography and 3D facial scan images are needed to analyze and evaluate the soft tissues of the entire face.
One major application of 3D imaging in orthodontics and oral and maxillofacial surgery is preintervention and postinterventions assessment of facial esthetics. To evaluate treatment outcomes with regard to soft tissues, preoperative and postoperative 3D photographs of the patient's face are registered. After registration of the 3D photographs, the differences between them can be visualized on a color scale or a distance map. In this way, the results of surgical and orthodontic treatment can be evaluated quantitatively and objectively. Investigators concluded that surface-based registration is an accurate method to compare 3D photographs of the same subject at different times. Therefore, 3D stereophotogrammetry is an accurate tool to evaluate facial changes (surgical or nonsurgical) over time. The soft tissue landmarks used in this study proved to be reproducible, easy to designate, and useful for facial soft tissue analysis. For superimposition and registration of pretreatment and postreatment 3D photographs, Day and Lee used a broad surface on the forehead, Soncul and Bamber used 5 points (right and left exocanthions and endocanthions, and soft-tissue nasion), and McCance et al used these 5 points and an additional 5 arbitrary points on the forehead. Recently, Baik and Kim used the 5 landmarks on the right and left exocanthions and endocanthions, and soft-tissue nasion for point registration, followed by area registration using the wide surface of the forehead as the reference for superimposing the 3D images to evaluate the soft-tissue changes after the correction of thye skeletal Class III malocclusion by 2-jaw surgery with genioplasty. Hence, in this study, we used initial point registration followed by the wide surface registration starting from right and left exocanthions and extending upward over the forehead on the area that would not be influenced by the treatment.
The maxilla was protracted forward significantly in groups 1 and 2 when compared with the untreated control group (group 1, 4.87 mm; group 2, 5.81 mm). The protraction rates were 0.61 and 0.65 mm per month for groups 1 and 2, respectively, without a significant difference between them. In previous studies, Cha and Ngan achieved 3.42 mm of maxillary advancement, and Lee et al reported 3.11 mm of advancement using facemasks anchored by miniplates at the zygomatic buttress area. Sar et al46 had 2.83 mm of maxillary advancement using facemasks anchored by miniplates fixed in the lateral nasal wall.


翻译考点：
考点 1：“zygomatic buttress” 推荐译为 “颧牙槽嵴”
考点 2：“self-tapping bone screws” 推荐译为 “自攻骨螺钉”
考点 3：“orthopedic force” 推荐译为 “矫形力”
考点 4：“centric occlusion” 推荐译为 “正中咬合”
考点 5：“cephalometric radiographs” 推荐译为 “头影测量片”
考点 6：“anterior crossbite” 推荐译为 “前牙反𬌗”
考点 7：“facial moulages” 必须译为 “面部扫描模型”，不能翻译为 “面部印模”
考点 8：“infrazygomatic buttress” 推荐译为 “颧下嵴”
考点 9：“mucoperiosteal flaps” 推荐译为 “粘骨膜瓣”
考点 10：“circummaxillary sutures” 推荐译为 “上颌周围骨缝”
考点 11：“soft tissue pogonion” 推荐译为 “软组织颏前点”
考点 12：“rapid maxillary expansion” 推荐译为 “快速上颌扩弓”
考点 13：“periodontal ligament” 推荐译为 “牙周膜”
考点 14：“symphyseal miniplates” 必须译为 “颏部微型钢板”