Using computed tomography to evaluate maxillary changes after surgically assisted rapid palatal expansion

Surgically assisted rapid palatal expansion (SARPE) is the procedure of choice for treating transverse maxillary deficiency in adult patients. The use of computed tomography (CT) as a method of evaluating the efficiency of this procedure has not been yet reported. Consequently, few landmarks for use in evaluating maxillary expansion have been defined. The goals of the present study were to define parameters to assess skeletal changes after SARPE and to use CT to evaluate those parameters. From June of 2004 to May of 2005, 15 patients underwent SARPE (a modified Le Fort I maxillary osteotomy without pterygomaxillary separation, together with a sagittal palatal osteotomy) according to a defined protocol. To determine the pattern of transversal expansion, linear and angular measurements of the anterior, intermediate, and posterior portions of the maxilla were evaluated in axial and coronal views. The cross-sectional area of the maxilla was calculated to obtain general information about maxillary expansion. The reliability of the method was confirmed. Significant overall expansion was observed. However, different patterns of expansion were seen in the three regions analyzed. In the anterior and intermediate portions of the maxilla, the increase in maxillary width was greater than that observed in the posterior portion. The transverse expansion of the maxilla achieved through SARPE without pterygoid plate separation was less than uniform. The accurate evaluation of the postoperative changes was heavily dependent upon images acquired through CT.     

Sagittal and vertical maxillary effects after surgically assisted rapid maxillary expansion (SARME) using Haas and Hyrax expanders

The purpose of this study was to evaluate the effect of surgically assisted rapid maxillary expansion on the sagittal and vertical maxillary planes. Thirty-three adult patients aged between 18 and 40 years who required surgically assisted rapid maxillary expansion were included in this study. They were divided into two groups: the Haas type expander (16) and the Hyrax type expander (17). All patients were subjected to subtotal LeFort I osteotomy with pterygomaxillary disjunction. Lateral cephalometric radiographs were taken during the preoperative assessment (T1), soon after completion of the expansion (T2), and 4 months after the end of the expansion (T3). The following cephalometric measures were obtained in each of the three radiographs for all the patients: SNA, SN palatal plane, Frankfurt horizontal plane. NA, CF-A, CF-NA, Nperp-A, CF-A, Frankfurt horizontal plane-ANS, and Frankfurt horizontal plane-PNS. Statistically significant changes were observed in the cephalometric measures: SNA, Frankfurt horizontal plane, NA, Nperp-A in the patients in the Haas group, and CF-A in the patients in the Hyrax group, demonstrating anterior displacement of the maxilla. The cephalometric measures SN.palatal plane, CF-A, CF-NA, Frankfurt horizontal plane-ANS, and Frankfurt-PNS plane that evaluated vertical displacement did not show changes in either group. The surgically assisted rapid maxillary expansion caused anterior displacement of the maxilla in both groups, but only the Haas group had statistical significance. Neither the Haas group nor the Hyrax group showed vertical displacement of the maxilla. When Hyrax and Haas groups were compared, there were no statistically significant differences for sagittal and vertical changes.     

Tunnel technique through three vertical buccal incisions to reduce nasolabial changes due to surgically assisted rapid palatal expansion

The aim of this technical note is to present a minimally invasive approach to the maxilla for segmental Le Fort I osteotomy in surgically assisted rapid palatal expansion (SARPE). This approach reduces the nasolabial changes that occur with the traditional circumvestibular approach.     

Transverse changes after surgically assisted rapid palatal expansion

The aim of this retrospective study was to investigate the amount of skeletal and dental expansion in patients submitted to surgically assisted rapid palatal expansion (SARPE). The sample consisted of 21 patients (14 female and seven male) with a mean age of 25.4 years (range 17.4–41.8 years). Postero-anterior (PA) cephalograms were taken pre-expansion (T1), immediately after expansion (T2), and at post-expansion retention of 120 days (T3). SARPE promoted significant transverse skeletal changes, which were maintained from T2 to T3. Dentoalveolar expansion and dental tipping were also observed in the region of the first molars and first premolars; however the net effect at the first molars was significantly less than that at the first premolars. No statistically significant effect on the width of the nasal cavity was observed. The findings indicate that peculiarities inherent to dental effects may influence the clinical options for SARPE. Skeletal expansions with SARPE were significant and stable. Dental changes were different between molars and premolars. The transverse changes after SARPE should be observed for future procedures related to the retention and the completion of orthodontic treatment.     

Maxillary sagittal and vertical displacement induced by surgically assisted rapid palatal expansion.

The purpose of this study was to investigate the sagittal and vertical effects on the maxilla induced by surgically assisted rapid palatal expansion. Twenty patients (average age, 25.6 years) who required a surgically assisted rapid palatal expansion procedure were available for this study. Each patient was banded with a Haas-type palatal expander, maxillary surgery was performed, and the expander was activated. Presurgical and postexpansion lateral cephalograms were taken for each patient. The measurements of SNA, Frankfort horizontal-nasion-A point, sella-nasion-palatal plane, A-point-nasion-perpendicular (in millimeters), 1-nasion-A-point, 1-sella-nasion, 1-nasion-perpendicular (in millimeters) were made on each cephalogram, and the presurgical and postexpansion tracings were superimposed on the cranial base to determine the changes in the anterior nasal spine and posterior nasal spine positions. Results showed that from the presurgical cephalogram to the postexpansion cephalogram SNA, Frankfort horizontal-nasion-A point and A-point-nasion-perpendicular had a mean increase of 0.60 degrees (P <.05), 0.65 degrees (P <.05), and 0.55 mm (P <.05), respectively; 1-nasion-A-point decreased 2.18 degrees (P <.05) and 1-sella-nasion decreased 1.53 degrees (P <.05). No significant maxillary vertical displacement was noted from the first cephalogram to the second. In conclusion, surgically assisted RPE did not significantly affect the maxilla vertically; however, it did induce a slight forward movement of the maxilla and a slight retroclination of the maxillary incisors sagittally (P <.05).     

Three-dimensional dentoskeletal changes following minimally invasive surgically assisted rapid palatal expansion: a prospective study

Dentoskeletal changes in minimally invasive surgically assisted rapid palatal expansion (SARPE) were evaluated using cone beam computed tomography (CBCT). This was a prospective study of 30 patients who underwent minimally invasive SARPE performed under local anaesthesia plus sedation by the same surgeon, in an ambulatory setting. Pre- and postoperative CBCT images were obtained for each patient. A statistically significant increase in the linear transverse dimensions of the maxilla occurred systematically. In the canine region, a mean increase of 5.84 mm occurred at the apex level and 7.82 mm at the crown level. These dimensions were 4.83 mm and 7.68 mm, respectively, in the molar region. The cross-sectional area of the maxilla increased by a mean 12.9 mm² at the palate level and 23.3 mm² at the crown level. Dental inclination to the buccal aspect was detected (mean 6.1° at the canines and 8.4° at the first molars). The alveolar process tipped buccally 10° at the molar level. Nasal width increased a mean of 3.0 mm at the canine level. Through a three-dimensional analysis, this study found that minimally invasive SARPE was effective in the correction of transverse maxillary discrepancies> 5 mm in non-growing patients. Although dental inclination to the buccal aspect occurred, significant expansion of the maxilla at the skeletal and dentoalveolar levels was confirmed.     

Statistical evaluation of possible factors affecting the sagittal position of the first permanent molar in the maxilla

A cephalometric analysis was designed to evaluate several factors that may affect the sagittal position of the maxillary first permanent molar. A total of 184 Class II and Class I malocclusion patients were randomly selected before orthodontic treatment. The mandibular and palatal planes were related to Frankfort Horizontal and used to create the interjaw or B angle. Age and cephalometric landmarks (Ba, N, point A, pterygomaxillary fissure, and maxillary molars) were projected at right angles to the Frankfort Horizontal for effective length. Actual maxillary length and actual molar location were determined by projecting landmarks at right angles to the palatal plane. Correlation coefficients and P values were used to evaluate the data with a minimal significance value of .05 to determine a 95% confidence level. A statistically significant linear and proportional positive correlation (P < .0001) existed between molar location, age, and maxillary size. There was a strong negative correlation (P < .0001), both linearly and as a proportion of the actual length of the maxilla, between the actual position of the maxillary molar and the interjaw and mandibular plane angles. A significant correlation also existed between the molar position and palatal plane angles. The results show that increased interjaw, mandibular, and palatal plane angles are accompanied by a more posterior position of the maxillary first molar in the maxilla, whereas the molar occupied a continuing more forward position in the maxilla with increasing age, cranial base length, and maxillary size.     

Postoperative nausea and vomiting after oral and maxillofacial surgery: a prospective study

Postoperative nausea and vomiting (PONV) is one of the most unpleasant experiences after surgery. It reduces patient satisfaction and also increases hospital costs due to longer hospitalizations. The aim of this prospective study was to determine whether orthognathic surgery is associated with more PONV than less invasive maxillofacial surgery. Three hundred and eight patients aged 8–87 years who underwent maxillofacial surgery were included. The PONV score, based on the Apfel score, was calculated preoperatively. PONV occurred in 142 (46.1%) patients during the first three postoperative days; these patients were further categorized as having postoperative nausea (PON) and/or postoperative vomiting (POV). PON was most frequent after orthognathic surgery to the mandible (75%), and POV was most frequent after maxillary surgery, including bimaxillary surgery, Le Fort I osteotomy, and surgically assisted rapid palatal expansion (SARPE) (43.1%). There was a small significant relationship between the preoperative PONV score and the incidence of PONV: patients experienced more PONV when the PONV score calculated preoperatively was higher. The incidence of PONV after orthognathic surgery was very high compared with the incidence after dental extractions and other minor surgeries. Further investigation is required to establish a strategy to reduce PONV after orthognathic surgery.     

Glue embolisation of a bleeding pseudoaneurysm related to surgically-assisted rapid palatal expansion

Vascular injuries after orthognathic surgery are rare, and mainly occur in young adults after Le Fort I osteotomies. We report the case of a 14-year-old girl who presented with life-threatening epistaxis one week after a surgically-assisted rapid palatal expansion (SARPE) followed by activation of a transpalatal distractor. Definitive treatment was superselective, catheter-directed, glue-embolisation of a bleeding bilobar pseudoaneurysm, which was located at an end branch of the left sphenopalatine artery.     

Effect of vomer position following surgically assisted rapid palatal expansion

Purpose

To evaluate the effect of vomer position and prevalence of periodontal dehiscence in patients who underwent surgically assisted rapid palatal expansion (SARPE). The null hypotheses were the following: (1) vomer position in the coronal plane does not influence the degree of skeletal and dental expansion; and (2) there is no association between expansion, periodontal dehiscence and vomer position.

Methods

Twenty-one patients were evaluated before treatment (T0) and immediately after SARPE expansion (T1). After SARPE, the vomer was in the right side in 11 patients and in the left in 10 patients. Skeletal and dental effects were evaluated using CBCT, landmarks and measurements.

Results

The maxilla and the nasal cavity expanded asymmetrically. The side containing the vomer had less skeletal expansion but more dental tipping. Dehiscence increased significantly from T0 to T1 and was associated with the amount of skeletal displacement, especially when greater than 3.20 mm. In the first premolars region, there was more than 2 mm of asymmetric expansion observed in 38.5% of the patients.

Conclusion

The null hypotheses were rejected. The side containing the vomer had less skeletal expansion of the maxilla and nasal cavity but more dental tipping. Dehiscence increased after expansion, but there were no differences between sides.

     

虚拟手术设计在双颌正颌手术中的精准性研究

目的评估虚拟手术设计在双颌正颌手术中的精准性,以期为临床提供参考。方法纳入需行双颌正颌手术的患者30例,利用CT数据和牙弓平面扫描数据建立复合颅骨模型,在Dolphin Imaging 11.7 Premium软件上模拟上颌骨LeFort I型骨切开术和双侧下颌支矢状骨劈开术,必要时行颏成形术,利用3D打印的手术导板将虚拟手术设计转移到术中。选择3个平面:眶耳平面(FHP)、面中平面(垂直于FHP且通过鼻根点)和冠状面(垂直于FHP且通过蝶鞍点)。选择6个标志点:上、下颌中切牙的近中接触点(UI、LI)以及上下颌第一磨牙的近中颊尖(U6-R、U6-L、L6-R、L6-L)。在虚拟手术模型和真实术后模型上测量选定标志点和对称平面之间的距离,并计算两模型之间的线性差异和总体平均线性差异(UI、LI、U6-R、U6-L、L6-R、L6-L分别与眶耳平面、面中平面和冠状面之间距离的平均差异)。确定由咬合平面、腭平面和下颌平面分别与眶耳平面和面中平面构成的角度值,并计算虚拟手术模型和真实术后模型之间的角度差异和总体平均角度差异。结果借助3D打印手术导板,虚拟手术设计被成功转移至实际手术中,所有患者术后对面型和咬合都很满意。虚拟与真实模型间的总体平均线性差异为0.81 mm(上颌骨0.71 mm,下颌骨0.91 mm);总体平均角度差异为0.95°(相对于眶耳平面的平均角度差异为1.10°,相对于面中平面的平均角度差异为0.83°)。结论虚拟手术设计有助于牙颌面畸形的诊断和治疗计划的制定,可以增加双颌正颌手术中骨块定位的精准性。     

上颌平面偏斜对牙列中线与正中矢状面吻合度影响

目的:针对颌面部不对称畸形患者,在计算机上应用正颌手术模拟软件,重建三维头颅模型并模拟正颌手术,通过对术前上颌平面偏斜的角度和模拟正颌术后上颌牙列中线与正中矢状面夹角的分析,得出二者之间的关系,为正颌手术提供参考。方法:选择在中国医科大学附属口腔医院口腔颌面外科就诊的20位颌面部不对称畸形患者进行研究,首先用三维CT影像重建出头颅模型,测量上颌平面与水平参考面的夹角,再利用软件模拟上颌Le FortⅠ型截骨,测量上颌牙列中线与正中矢状面的夹角,最后应用统计学软件进行统计分析,得出两个角度间的关系。结果:颌面部不对称畸形患者,上颌平面和水平参考面的夹角与上颌牙列中线和正中矢状面夹角存在正相关的线性关系,经过统计学分析,得到上颌平面和水平参考面的夹角X与上颌牙列中线与正中矢状面夹角Y的直线回归方程,为Y=1.997+12.109X。结论:颌面部不对称畸形患者,上颌平面偏斜对牙列中线与正中矢状面的吻合度存在相关性,该相关性可为正颌手术的整复提供原则性的参考。     

Dental tipping and rotation immediately after surgically assisted rapid palatal expansion

The purpose of this investigation was to evaluate the effects of dental tipping and rotation immediately after surgically assisted rapid palatal expansion (SARPE). Fourteen patients (10 females, four males; mean age 25.6 years) who required a SARPE procedure were available for this study. A palatal expander appliance was cemented on four abutment teeth (first premolars and first molars) of each patient 1 week prior to surgery. Maxillary study models were taken before surgery and 2-3 weeks after full expansion (7 mm). Each model was trimmed to have the base parallel to its occlusal plane. From an occlusal view, measurements were made to determine if the abutment teeth underwent rotation from SARPE. From a postero-anterior view, the abutment teeth were examined for any tipping effect due to SARPE. The results showed that from pre- to post-expansion, the two first premolars displayed 2.32 +/- 8.29 degrees of mesiobuccal rotation (P > 0.05) and the two first molars displayed 3.09 +/- 5.89 degrees of mesiobuccal rotation (P > 0.05). Each first premolar showed 6.48 +/- 2.29 degrees of buccal tipping (P < 0.05) and each first molar 7.04 +/- 4.58 degrees of buccal tipping (P < 0.05). SARPE induced a slight mesiobuccal rotation (P > 0.05) and significant buccal tipping of the first premolars and the first molars (P < 0.05). Some overexpansion is suggested to counteract the relapse effect of buccal tipping of the posterior teeth that takes place during SARPE.     

The effect of subspinal Le Fort 1 corticotomy on nasal morphology in surgically assisted rapid palatal expansion

The purpose of this retrospective study was to evaluate the influence of subspinal Le Fort 1 corticotomy (SLF1C) on nasal morphology in patients treated with surgically assisted rapid palatal expansion (SARPE) using three-dimensional (3D) stereophotogrammetry images. A total of 64 patients were enrolled in the study and divided into two groups according to the surgical approach that was used: in group 1 (n = 32) SARPE was performed using a conventional Le Fort 1 corticotomy (CLF1C), and in group 2 (n = 32) SARPE was performed using a subspinal Le Fort 1 corticotomy (SLF1C). Measurements of alar and columellar width, and nasolabial angle were taken on 3D stereophotogrammetry images before and after SARPE using Vectra 3D camera system. Both surgical groups showed a statistically significant increase in alar and columellar width, and nasolabial angle postoperatively (p<0.05). SLF1C resulted in significantly smaller changes of the columellar base postoperatively (p=0.0456). The data suggests that SARPE with an osteotomy of the anterior nasal spine as an additional step to the conventional Le Fort 1 corticotomy results in a smaller increase of the columellar base.     

Long-term stability of surgical-orthodontic correction of class III malocclusions with long-face syndrome

Objectives: In the first place, to evaluate skeletal changes of the maxilla and mandible induced by surgical-orthodontic correction of malocclusions class III with long-face syndrome and secondly, to analyze the stability of these skeletal changes in the long term (more than 6 years). Design of Study: A retrospective, unicentric and longitudinal study of 19 patients who had undergone surgical and orthodontic therapy for class III skeletal malocclusion with long-face syndrome was undertaken. A cephalometric analysis based on 8 angle measurements, and statistical analyses at three different points in time (before orthodontic treatment, after orthognathic surgery and after a retention period of at least 6 years) were carried out. Results: The changes produced following surgery show that, with the exception of the maxillary plane and the facial axis, all other variables presented changes of great statistical difference. Conclusions: Skeletal changes after orthodontic-surgical correction present maxillary advance, mandibular regression and mandibular anterorotation. The angles that represent the mandibular vertical position (ramus angle, goniac angle and mandibular plane angle) showed statistically significant relapses and no stability in contrast to the facial axis. Key words:Long term results, stability, relapse, orthognathic surgery, class III, long face.     

骨支持式手术辅助上颌骨快速扩弓位移分布的三维有限元分析

目的:研究骨支持式手术辅助上颌骨快速扩弓中颅面部各解剖部位的位移情况.方法:建立骨支持式手术辅助上颌骨快速扩弓系统的三维有限元模型,手术方式采用腭中缝联合侧方皮质骨切开术,模型上选取24个解剖结构,加载横向7mm扩弓量,比较分析颅面部各个解剖部位在矢状向、横向、垂直向的位移分布情况.结果:矢状向观,上颌骨各解剖结构都有明显的向前位移的趋势,而面上部解剖结构都有向后移位的趋势.横向正面观,颅上颌复合体呈金字塔样打开,鼻腔底部明显扩大约4.5mm;殆面观,支抗牙的牙根位移(第一前磨牙为2.92mm,第一磨牙为3.26mm)小于相应区域颊侧牙槽骨的位移(第一前磨牙区3.76mm,第一磨牙区3.93mm),腭板前部比后部扩开更大.垂直向观,上颌骨正中区的腭板有向下位移的趋势,颅面部其余解剖部位都向上移动.结论:骨支持式手术辅助上颌骨快速扩弓时,上颌骨在三维方向上有不同程度的移动、旋转和侧方倾斜,利用这些变化,可以辅助矫正轻度颅颌面畸形.骨支持式扩弓器将扩弓力直接传导到骨骼上,因此可以很好地避免牙支持式扩弓器扩弓时引起的牙及其周围支持组织损伤等严重并发症.     

Skeletal and dentoalveolar changes in the transverse dimension using microimplant-assisted rapid palatal expansion (MARPE) appliances

Conventional rapid palatal expansion (RPE) has been proven to be a reliable treatment for correcting transverse maxillary deficiency in young patients. However, side effects including dental tipping and risk of periodontal problem limited its application to young patients after the pubertal growth spurt. Surgically assisted rapid palatal expansion (SARPE), a supplement to RPE, could be applied in skeletally mature patients. However, SARPE was an invasive method, and the morbidity, risks and cost related to surgical treatment might discourage many adult patients. The use of Microimplant-Assisted Rapid Palatal Expansion (MARPE) appliance, which can potentially avoid surgical intervention, is gaining popularity in treatment of maxillary transverse deficiency (MTD) in young adolescent patients. However, the literature on the skeletal and dentoalveolar changes with this appliance is scarce. To evaluate the immediate skeletal and dentoalveolar changes in the transverse dimension with the maxillary skeletal expander (MSE), a MARPE appliance with hybrid anchorage, using cone-beam computed tomography (CBCT). Twenty-two patients (11 males and 11 females, mean age 14.97 ± 6.16 years) with transverse maxillary deficiency were treated using the MSE (Biomaterials Korea, Inc., Seoul, Korea). The appliance consisted of a central expansion screw that were welded to four tubes that served as guides for microimplant placement. The microimplants were 1.8 mm in diameter and 11 mm in length. The longer length of microimplants permitted bicortical engagement of the palatal and nasal floor, reducing the force transmitted to the anchored teeth during expansion. The appliance activation varied with age and skeletal maturity of the patient. The expansion was terminated when 2–3 mm of overexpansion was achieved. CBCT scans were taken before treatment (T1) and immediately after expansion (T2). Measurements were taken to evaluate the amount of total expansion, skeletal expansion, and angular dental tipping at the first molar region. A total expansion of 5.41 ± 2.18 mm was achieved, 59.23 ± 17.75% of which was attributed to skeletal expansion (3.15 ± 1.64 mm) with the first molars exhibiting buccal tipping of 2.56 ± 2.64°. The use of MARPE appliances such as MSE can be used to correct transverse maxillary deficiency in adolescent patients with minimal dentoalveolar side effects.     

上颌复合体手术辅助腭扩展应力分布和位移的研究

目的 模拟手术辅助腭扩展术,分析上颌骨复合体应力分布与位移趋势.方法 在力学相似性较高的上颌骨复合体三维有限元模型上,模拟第一磨牙处颊侧骨皮质切开辅助腭扩展术,计算各标志点的应力及位移,所得结果与常规腭扩展相比较.结果 颊侧骨皮质切开术辅助腭扩展开展牙弓,可有效增加横向扩展的位移,尤其在尖牙和前磨牙区.同时鼻腔和腭盖下降,有助于降低通气阻力.结论 颊侧骨皮质切开辅助腭扩展的方法效果确切.     

上颌复合体手术辅助腭扩展应力分布和位移的研究

目的 模拟手术辅助腭扩展术,分析上颌骨复合体应力分布与位移趋势.方法 在力学相似性较高的上颌骨复合体三维有限元模型上,模拟第一磨牙处颊侧骨皮质切开辅助腭扩展术,计算各标志点的应力及位移,所得结果与常规腭扩展相比较.结果 颊侧骨皮质切开术辅助腭扩展开展牙弓,可有效增加横向扩展的位移,尤其在尖牙和前磨牙区.同时鼻腔和腭盖下降,有助于降低通气阻力.结论 颊侧骨皮质切开辅助腭扩展的方法效果确切.     

Sagittal airway dimensions following maxillary protraction: a pilot study

The relationship between changes in the position of the maxillary structures caused by maxillary protraction therapy and airway dimensions have not been investigated as comprehensively as the accompanying skeletal changes. The purpose of this study was to examine the effects of rapid palatal expansion (RPE) used in conjunction with maxillary protraction headgear on the sagittal dimension of the airway. The treatment sample consisted of 19 Class III patients (12 girls, 7 boys) with a mean age of 10.51 +/- 1.15 years, presenting with maxillary retrognathism. A cap splint type rapid palatal expander that had hooks between the upper lateral and canine teeth was used intraorally, and a Petit type facemask device extraorally, for an average of 6.78 +/- 0.93 months. Pre- and post-treatment cephalometric radiographs were evaluated. The results of the study revealed that point A moved anteriorly. The palatal plane showed a counter-clockwise rotation matched by the clockwise rotation of the mandible and an accompanying decrease in SNB angle. The vertical parameters showed a statistically significant increase. The head was in a more extensive position in relation to the cervical vertebrae. The nasopharyngeal airway measurements (PNS-ad1, PNS-ad2) showed an increase of 2.71 +/- 3.35 and 3.03 +/- 2.37 mm, respectively. These results demonstrated that limited maxillary widening together with protraction of the maxilla, improve nasopharyngeal but not oropharyngeal airway dimensions in the short term.