Maxillary Movement Research Articles

An Integrated Approach, Orthodontic and Prosthetic, in a Case of Maxillary Lateral Incisors Agenesis

Background: Among tooth anomalies, missing teeth is one of the most frequent, and it can be related to different therapeutical sets of problems. Often, an integrated approach that interests both orthodontists and prosthodontists is necessary, and in some cases also the periodontists. Methods: In this paper the authors report a clinical case of a 14-year-old patient, affected by maxillary bilateral incisors agenesis, molar bilateral II class and deep bite, treated in the Department of Orthodontics and Pedodontics of the University of Messina. The orthodontic treatment target was the distal movement of the maxillary molar, and the recovery of the space necessary for the prosthetic restoration of the missing lateral incisor. Maxillary molars distal movement was performed with a Distal Jet apparatus, skeletally supported by two miniscrews (Distal-Screw, American Orthodontics, Sheboygan, WI, USA). After molar relationship correction, a multi-bracket bimaxillary orthodontic appliance was bonded using Empower Brackets (American Orthodontics, Sheboygan, WI, USA). At the end of orthodontic treatment a Maryland bridge, bonded on the central incisors and cuspids, was used in order to maintain the space necessary for the insertion of dental implants in the region of 1.2 and 2.2 Results: A class II molar relationship was corrected, with an improvement of the deep bite, and the space necessary for implant insertion was recovered Conclusion: A skeletally supported Distal Jet was efficient for molar distalization, with the advantage of not having any loss of anchorage in the anterior part of the dental arch. This apparatus does not need patient compliance, have favorable aesthetics and also give the possibility to perform asymmetric activations.

Inferior Maxillary Repositioning Remains Stable 1 Year After Surgery but Entails a High Risk of Osteosynthesis Failure

Inferior maxillary repositioning has continued to be among the most unstable orthognathic procedures. The overall purpose of the present study was to measure skeletal stability after inferior maxillary repositioning. We implemented a retrospective cohort study. The study cohort was derived from all orthognathic patients who had undergone treatment from January 2011 to December 2013 in Odense University Hospital. The inclusion criteria were orthognathic surgery with inferior maxillary repositioning in patients without maxillary segmentation or cleft lip/palate. The exclusion criteria were nonattendance at follow-up visits or requiring reoperation before the 1-year follow-up point. The primary predictor variable was the time from the 1-week follow-up examinationto the 1-year follow-up examination. The primary outcome variable was maxillary skeletal movement. The other variables of interest were age, gender, preoperative occlusal relationship, maxillary movement obtained, and surgery type (mono- or bimaxillary procedure). Skeletal stability was measured at the centroid, anterior, and posterior nasal spines using the semiautomatic measurement technique. Skeletal stability was clinically defined as less than 2mm of movement in any direction. The positive directions for the 3 axes were right, anterior, and superior. The data were analyzed using mixed model linear regression analysis and 1-sample t tests. A total of 17 patients were included in the present study (mean age, 28years; female gender, 35%; bimaxillary surgery, 59%). Inferior maxillary repositioning was stable with less than 0.3mm mean skeletal movement in any direction. Only 1 patient had experienced a relapse of more than 1mm in the posterior direction; no movement exceeded 2mm. However, 3 patients were excluded from the present analysis, because they had required reoperation during the first year after surgery for osteosynthesis failure. Inferior maxillary repositioning was stable during the first year after surgery; however, the complication rate was high (15%). Thus, this procedure might still benefit from the use of more rigid patient-specific printed plates to increase postoperative stability.

S4B-19 SESSION 4B: ORTHOGNATHIC / TREACHER-COLLINS EVALUATING THE PERCEPTION OF NASAL CHANGES AND ITS CORRELATION TO ANGULAR MEASUREMENTS AFTER ORTHOGNATHIC SURGERY

Introduction: Maxillary movements in orthognathic surgery are supposed to be responsible for changes in position and shape of the nose. Skeletal maxillary advancement produces soft tissue responses correlated to sagital movements of the underlying bone. Precise prediction of nasal changes is difficult and depends on individual variations. Improvement or deterioration of nasal harmony may occur and is the main reason to discuss the role of rhinoplasty during or after orthognathic surgery. The purpose of the present study is to evaluate changes in columella-labial angle (CLA) and naso-facial angle (NFA) after orthognathic surgery and its correlation to a visual perception of nasal changes by experts. Methods: Preoperative and postoperative digital photographs of 24 patients with class III deformities who underwent maxillary advancement were assessed. Patients were divided in two groups: isolated maxillary advancement (MA, n=12) and maxillary advancements associated with mandibular setback (MM, n=12). All lateral photographs were taken with patients in the natural head position and centric occlusion. CLA and NFA were measured in lateral view using ImageJ software and pre-op and post-op results were statistically compared. A survey was performed by 3 independent plastic surgeons who randomly received pre-op and post-op lateral images and were asked to evaluated all nasal changes with a 3-point scale: worsened, neutral or improved. Results: In MA group, comparison of pre-op and post-op images showed an increase of the NFA after surgery (p=0.028). There was no significant difference in CLA pre-op and post-op measurements (p=0.754). In MM group, neither NFA nor CLA changes were significantly different (p=0.170 and p=0.209 respectively). In MA group, 7 evaluations presented as “improvements”, 4 as “neutral” and 1 as “worsened”. In MM group, 9 evaluations presented as “improvements” and 3 as “neutral”. No significant difference between visual perception of MA and MM groups was shown. Conclusion: Nasal aesthetic improvement verified by the evaluators was not consistent with main changes in angular measurements. Visual perception is subjective and takes into account not only the nose, but the harmony between different elements of the face, even when performed by skilled plastic surgeons. Global improvement of the face after maxillary surgery can be a confusing factor for the individual analysis of the nose. The necessity of rhinoplasty to induce major changes in nasal shape therefore should not be discussed before maxillary advancements. This study strengths the indication of nasal surgery as an individualised procedure to be discussed after orthognathic surgery.

Pharyngeal Airway Modifications in Skeletal Class III Patients Undergoing Bimaxillary Advancement Surgery

The purposes were to study the pharyngeal airway in patients with skeletal Class III malocclusion submitted to surgical orthodontic treatment and to correlate the alterations with bone movements. The sample consisted of multislice computed tomography images from 13 patients obtained before and 6months after maxillomandibular advancement surgery. The following measurements were obtained using Dolphin Imaging software (Dolphin Imaging, Chatsworth, CA): volume and area of the oropharynx, nasopharynx, and total airway, as well as the most constricted area, anteroposterior and lateral dimensions of the narrowest axial cross-sectional area, and airway length. The paired ttest was applied at a significance level of 5%. Sagittal displacement of the maxilla and mandible was correlated with airway alterations using the Pearson correlation test. Alterations in airway measurements were observed in all patients after surgery. We noted a significant increase (P<.05) in total airway area, oropharyngeal area, and anteroposterior dimension of the most constricted area, as well as a significant reduction (P<.05) in airway length. A significant correlation (P<.05) was observed between nasopharyngeal area and maxillary movement and between airway length and mandibular movement (P<.05). The results of this study suggest significant alterations in pharyngeal airway measurements when preoperative and postoperative periods of bimaxillary advancement surgery were compared.

Changes in scleral exposure following Le Fort І maxillary advancement or impaction

Background and objectivesInferior scleral exposure is an aesthetic as well as functional concern. The purpose of this study was to evaluate and compare changes in scleral exposure following Le Fort I (LFI) maxillary advancement or impaction. Methods43 patients with inferior scleral show who underwent LFI osteotomy were studied. Patients underwent two types of surgery: maxillary advancement was performed in 21 patients and maxillary impaction in 22 patients. Preoperative and 6-month postoperative frontal photographs of patients were analyzed with Adobe Photoshop CC 2018 and compared for scleral exposure by the ratio of the distance between inferior eyelid margin and corneal limbus to eye height. ResultsThe mean maxillary movement was 6.14 mm advancement in LFI advancement group and 4.4 mm impaction in LFI impaction group. The mean scleral show ratio decreased by 4.25% (4.4% in the right and 4.1% in the left eye) in LFI advancement and 3.65% (3.5% in the right eye and 3.8% in the left eye) in LFI impaction group. These changes were statistically different in each group but they were the same when comparing two groups (p-value > 0.05). ConclusionBoth LFI advancement and LFI impaction significantly decreased scleral exposure in our patients.

Three-Dimensional Pharyngeal Airway Changes After 2-Jaw Orthognathic Surgery With Segmentation in Dento-Skeletal Class III Patients.

To investigate short- and long-term three-dimensional changes of pharyngeal airway morphology and hyoid bone position in dento-skeletal class III deformity patients after 2-jaw orthognathic surgery with segmentation. A retrospective analysis has been performed on patients with dento-skeletal class III deformity who had undergone orthognathic 2-jaw surgery with segmentations, presenting both pre- and post-surgical cone-beam computed tomographys. Three-dimensional skeletal movements, pharyngeal airway changes and hyoid bone position were measured and correlated. The mean short term postsurgical review period for all included 47 patients was 5.8 ± 2.2 months. Thirteen patients among them provided a mean long term period of 26.4 ± 3.4 months. The mean postsurgical maxillary movement was 2.29 ± 2.49 mm in vertical, 2.02 ± 3.45 mm in horizontal direction, respectively, while the mandibular movement was 6.49 ± 4.58 mm in vertical, and -5.85 ± 6.13 mm in horizontal direction. In short-term, the vertical length of nasopharynx was found to be reduced (P = 0.005) but increased for the oropharynx (P < 0.001). Furthermore, the oropharyngeal minimum cross-sectional area has decreased significantly (P = 0.013). The hyoid bone moved posterosuperiorly, however, with only its horizontal movement found to be significant (P = 0.043). No significant result was detected in long-term analyses, neither in postsurgical pharyngeal airway changes nor the hyoid bone movement. There were no significant differences in pharyngeal airway measurements (P > 0.05) detected between patients with and without genioplasty advancement. Two-jaw orthognathic surgery in dento-skeletal class III patients led to a statistically non-significant reduction of the post-surgical airway volume in both short- and long-term. Although the post-surgical oropharyneal minimum cross-sectional area was decreased significantly in the short term, this finding did not persist in the long term.

Tracking Accuracy of a Stereo Camera-Based Augmented Reality Navigation System for Orthognathic Surgery

Tracking accuracy is critical to successful augmented reality (AR) in the diagnosis and surgical correction of maxillofacial deformities. The present study investigated the tracking accuracy of an AR navigation system combined with a stereo camera during repositioning of the maxilla after a Le Fort I osteotomy using a 3-dimensional skull model and compared the tracking accuracy with that of an existing infrared (IR)-based optical tracking system (OTS). Five maxillary surgery plans were designed using a 6 degrees-of-freedom articulator that allowed maxillary movement to be set up quantitatively (target distance, 5mm). To evaluate the accuracy of the stereo camera AR navigation system, it was compared with a commercially available and commonly used IR-based OTS. The mean error was 0.0584mm in the IR-based OTS and 0.0596mm in the AR navigation system. The mean accuracy was 98.83% in the IR-based OTS and 98.81% in the AR navigation system. In this study, the stereo camera-based AR navigation system fabricated and analyzed by the authors was designed for accuracy. The experiments showed its reliability and accuracy. The hardware developed for this AR navigation system displayed accuracy similar to that of existing high-cost imported devices at a substantially lower cost. In addition to surgery, potential applications of the AR navigation system include patient communication and training for novice clinicians.

Cephalometric analysis of the pharyngeal airway space after maxillary advancement surgery.

This study evaluated the effect of maxillary advancement surgery on the size of the pharyngeal airway space (PAS). Lateral cephalometric radiographs were collected for 90 patients (29 men and 61 women; average age, 27.2 ± 8.1 years) before (T1) and 1 year after (T2) maxillary advancement surgery. Horizontal and vertical changes in the maxilla and PAS were measured and classified by distance. The maxilla was advanced horizontally by 2.9 ± 1.7 mm and vertically by 2.7 ± 1.4 mm. Upward maxillary movement of ≥4 mm significantly increased PAS (mean change in PAS, 2.6 mm), and upward maxillary movement significantly decreased the posterior nasal spine to the P-point. Only patients with vertical advancement ≥4 mm and horizontal advancement of 3 mm had significant increases in all three PAS parameters. Although forward maxillary movement is believed to have a large effect on PAS, it is suggest that upward vertical movement is more effective for improving PAS. Both the extent and direction of maxillar movement should be considered. Future studies should use cone-beam computed tomography to evaluate the effect of axial direction and differences in PAS.

Extracorporeal shockwave treatment impedes tooth movement in rats

BackgroundAccelerated tooth movement has been a topic of interest for orthodontic research recently. Surgically facilitated orthodontic treatment has been shown to be an effective approach to accelerate tooth movement; however, it remains invasive, requires additional surgery, and may increase post-operative complications. In this study, we evaluate the effects of extracorporeal shockwave treatment (ESWT), a non-invasive approach to regenerate alveolar bone, on orthodontic tooth movement in rats.Materials and methodsSeventy-two male rats, aged 10 weeks old, were subjected to 10-cN closed-coil nickel-titanium springs for unilateral maxillary first molar tooth movement. One group of rats received a single treatment of extracorporeal shockwave treatment at 500 impulses at energy flux density 0.1 mJ/mm2, with a pulse rate of 5 pulses per second immediately after spring installation while the non-ESWT-treated group served as a control group. The rats were sacrificed at day 3, 7, 14, 21 and 28 for tooth movement evaluation and sample analyses. Faxitron radiography, histological, double bone labeling and gene expression analyses were performed. Serum biochemistry was evaluated at day 3, 7 and 28 of the study. Kruskal-Wallis analysis of variance was used to determine the mean difference among groups, and multiple comparisons were analyzed by Mann-Whitney-U tests with a significance level = 0.05.ResultsThe results demonstrated that tooth movement in the ESWT-treated rats (0.11 ± 0.07 mm) was impeded compared to the tooth movement in the non-ESWT-treated rats (0.44 ± 0.09 mm). ESWT up-regulated several osteoblastic and osteoclastic gene markers and cytokines; however, the effects on osteoclasts were only transient. Double-fluorescence bone labeling demonstrated that osteoblastic activity increased after ESWT treatment. There was no difference in systemic RANKL/OPG ratio between groups.ConclusionsESWT at 500 impulse at energy flux density 0.1 mJ/mm2 increased osteoblast and osteoclast activities and imbalanced bone remodeling resulting in impeded tooth movement in rats.

Intra- and Postoperative Complications of Le Fort I Maxillary Osteotomy.

The Le Fort I maxillary osteotomy is a versatile and simple procedure, which has gained popularity nowadays, to correct a wide range of malocclusion and maxillofacial deformities. This procedure is often associated with significant but rare postoperative complications. The aim of this study was to evaluate the types and frequencies of intra- and perioperative complications related to Le Fort I osteotomies in noncleft Iranian patients. In this prospective study, all the healthy systemic patients, (ASA I, II) with the age range of 18 to 30 years from both genders, who had the skeletal class II or III deformities and required only isolated 1-piece maxillary Le Fort I osteotomy, were included in this study. These patients had no craniofacial cleft history and were candidates for orthognathic surgery in Maxillofacial Surgery Department of Qaem Hospital of Mashhad (Iran), 2015 to 2017. All of the operations were carried out or supervised by a single surgeon and anesthesiologist using the same protocol. The patients were monitored for occurrence of intra- or postoperative complications till 6 months. The t-test, Chi-squared test, and Fisher exact test were performed for data analysis using SPSS version 16 (SPSS Inc, Chicago, IL). In the present study, a total of 114 consecutive patients with the average age of 22 ± 5 years from October 2015 to November 2017 were recruited. About 77 (67.54%) patients were presented skeletal class III deformity and 37 (32.46%) were class II. The most prevalent maxillary movement after Le Fort I osteotomy was identified to be isolated maxillary advancement in 51 (44.75%) patients. Only 10 (8.77%) of all 114 patients confronted surgical complications. Hemorrhagic complication (arterial bleeding from descending palatine artery and epistaxis) and anatomic complications (septal deviation and bad fracture) would be the most prevalent complications with the frequency of 5.25% and 3.5% in total. Maxillary setback with impaction presented the highest rate (36.4%) of complications compared to other maxillary movement types. On balance, there was a significant association between Le Fort I surgery complications and maxillary movement types in our research (P = 0.002). The rate of intra- and postoperative complications following Le Fort I osteotomy for healthy noncleft adults in our center was low. Therefore, it can be concluded that this technique is safe and reliable. The maxillofacial surgeon should pay more attention for prevention or even management of the risk of intra- and perioperative complications in patients with anatomic irregularities (previous craniofacial cleft or trauma history) and those who required maxillary setback concomitant with impaction movements.

Precise control of maxillary multidirectional movement in Le Fort I osteotomy using a surgical guiding device

We introduced a surgical protocol to achieve accurate maxillary multidirectional movement in Le Fort I osteotomies. This comprised a way of controlling precision and a guiding device together with prebent titanium plates. We evaluated the protocol using a semiautomated 3-dimensional assessment in 22 patients with maxillary multidirectional movement (movement in three or more of six directions). Operations were all done between October 2015 and April 2017 by the same surgeon, who followed the protocol strictly. To evaluate the accuracy, we measured the deviation of the orientation of landmarks and of the upper dentition. All cases were followed up for at least a year. They all involved maxillary movement in at least three directions, and nine involved movement in six. The guiding device was used intraoperatively in all cases. Vertical deviation of the segments of bone was often detected during removal of bone, and sagittal deviation in three cases, but we found no transverse deviations. The assessment of accuracy showed that the mediolateral, anteroposterior, and superoinferior translations of landmarks were all less than 1mm, with mean values of 0.29, 0.43, and 0.39mm, respectively. The pitch, roll, and yaw of the upper dentition were also less than 1°, with mean values of 0.60°, 0.35°, 0.36°, respectively. The proposed protocol allowed accurate reposition of the maxilla with multidirectional movement during Le Fort I osteotomy.

Effect of Mandible and Maxilla Osteotomies on Velar, Oropharyngeal, and Hypopharyngeal Diameter

There is a lack of anatomic comparisons between maxillomandibular advancement (MMA) and other bony surgical treatments of obstructive sleep apnea (OSA). Surgical procedures were simulated in cadavers to evaluate their ability to expand the posterior airway space (PAS). The following bony advancement surgeries were performed on each of 9 cadavers: genioglossal advancement (GGA); genioplasty with advancement of the genioglossus, geniohyoid, and anterior digastric muscles (GPA); bilateral sagittal split osteotomy; Le Fort I maxillary advancement; Le Fort I maxillary anterior impaction osteotomy (LFAI); MMA; MMA plus GPA; and MMA plus LFAI. Bony advancements were performed at increasing distances and change in PAS anteroposterior (AP) diameter was measured at the levels of the velum, oropharynx, and hypopharynx. Change in PAS varied in a linear fashion with advancement surgical maneuvers. GPA led to agreater increase in AP distance at the levels of the oropharynx and hypopharynx compared withGGA.LFAI showed a greater increase in AP distance at the velum compared with MMA. All maxillary movements showed greater AP expansion in the PAS at the velum compared with mandibular advancements. Static AP expansion of the PAS at the levels of the velum, oropharynx, and hypopharynx occurs in a roughly linear and predictable pattern with different bony surgical procedures used in OSA surgery. MMA alone and MMA plus GPA had the overall greatest effect at all airway levels. GPA had a greater effect on expansion of the oropharynx and hypopharynx compared with GGA.

Optimized 3D virtually planned intermediate splints for bimaxillary orthognathic surgery: A clinical validation study in 20 patients

Orthognathic surgery is indicated for the treatment of significant skeletal malocclusions and facial dysmorphosis. Recent technological developments allow surgeons to virtually plan the orthognathic jaw movements. When producing intermediate splints, overlap between the upper and lower dentitions can occur. Autorotation of the mandible is often used as a solution for this problem. The purpose of this study was to present an optimized approach to fabricate digital intermediate splints based on the use of a scanned thick wax bite to overcome dental overlap during planning.Twenty patients (9 males and 11 females) undergoing bimaxillary orthognathic surgery participated in this prospective study. Planning of the maxillary movements was conducted by the same surgeon. The thick wax bite was scanned using an intraoral scanner and a special CBCT protocol. The fabrication of the intermediate splints was done by means of conventional model surgery and virtual 3D planning-printing. The splints were clinically assessed by comparing the digitally printed intermediate splints to the corresponding conventional set-up which served as the clinical standard. Moreover, reproducibility and comparison tests between the scanned wax bites were implemented.The root mean square (RMS) for the reproducibility and comparison tests was respectively 0,15 mm (SD 0,24 mm) and 0,19 mm (SD 0,08 mm). 19 out of the 20 intermediate digitally 3D printed splints were clinically accepted.This proposed protocol can be considered as an optimization to the current 3D planning protocols of bimaxillary orthognathic surgery.

Laser-Assisted Indocyanine Green Imaging for Assessment of Perioperative Maxillary Perfusion During Le Fort I Osteotomy: A Pilot Study

To determine the changes in maxillary perfusion during different stages of Le Fort I osteotomies as measured by laser-assisted indocyanine green imaging (LAICGI) and to determine whether various clinical factors affect maxillary vascular perfusion. The medical records of those who had undergone Le Fort I osteotomy with LAICGI at the University of Illinois from 2016 to 2017 were reviewed retrospectively. The maxillary perfusion levels using LAICGI were measured before induction, after induction, after down fracture, after segmentalization (for segmental osteotomies), and after wound closure. The effects of clinical variables, including gender, race, American Society of Anesthesiologists physical status, type of Le Fort I osteotomy, intraoperative status of the descending palatine vessels, maxillary movements (anteroposterior, vertical, transverse), and hemodynamic data (mean arterial blood pressure, heart rate), were analyzed. Compared with the preoperative baseline values, the indocyanine green (ICG) levels decreased after down fracture and mobilization, segmentalization, and wound closure; no statistically significant differences were found among these 3 points. Segmentalization did not affect the ICG levels compared with the nonsegmentalized cases. Male gender and the amount of maxillary impaction were significantly associated statistically with decreased ICG levels, although the difference was not clinically significant. Compared with the baseline levels, maxillary perfusion, as measured by LAICGI, decreased from down fracture to wound closure. Segmentalization did not appear to influence maxillary perfusion, although male gender and impaction were associated with decreased perfusion. Because of its safety and convenience, LAICGI shows promise as a method of assessing maxillary perfusion in future largescale prospective studies linking perioperative perfusion to the occurrence of aseptic necrosis.

Accuracy of Le Fort I osteotomy in bimaxillary splint-based orthognathic surgery: focus on posterior maxillary movements

This retrospective study was performed to verify the accuracy of horizontal and vertical repositioning of the maxilla in bimaxillary osteotomy with a focus on posterior vertical displacement. Data from 39 orthognathic patients undergoing bimaxillary surgery including a one-piece Le Fort I osteotomy with pitch rotation and advancement at the University Hospitals of Leuven (Belgium), between January 2015 and April 2016, were included in the study. Preoperative and 1-week postoperative lateral cephalograms were digitized and imported into cephalometric software. Horizontal and vertical measurements of dental landmarks were used to assess the accuracy of maxillary repositioning, and errors were reported in terms of the mean and absolute mean. The horizontal advancements were randomly under- and over-corrected an average of 1.4mm±1.2mm. Vertical repositioning of the anterior maxilla followed the planning. A tendency for under-correction was found for posterior vertical intrusion of the maxilla. The same tendency towards under-correction of posterior maxillary inferior repositioning was detected when planned movements were greater than 3mm. For all studied groups, no significant difference was found between the planning and the results achieved, validating the use of intermediate splints.

Orthognathic Surgery and Rhinoplasty: Simultaneous or Staged?

Orthognathic surgery can significantly impact the nasolabial envelope, and at times requires an adjunctive rhinoplasty. The purpose of this study was to evaluate nasal morphology in orthognathic patients, focusing on predictive variables, and the need for and timing of definitive rhinoplasty. Based on these data, an algorithm for the implementation of adjunctive rhinoplasty is proposed. A review of cases over a 3-year period was completed. Information regarding demographic, diagnostic, and operative details; nasal morphology; and use of rhinoplasty was compiled. Three-dimensional images were used to quantify anatomical variables. Over 589 patients were reviewed during this period. Of these, 163 fulfilled inclusion criteria for this study. The mean age was 23.3 years. In total, 41.7 percent of orthognathic cases underwent adjunctive rhinoplasty. Of these, 82.4 percent were staged and 17.6 percent were simultaneous. The average time between staged procedures was 208 days. When simultaneous, 16.7 percent of the orthognathic procedures had significant maxillary movement (advancement >4 to 5 mm, impaction >2 mm, alar base excisions); in comparison, 92.9 percent of staged cases had significant maxillary movement (p < 0.0001). All patients had self-reported satisfaction with functional and aesthetic results during the follow-up period. Nasal and jaw deformities are intricately interlinked. In this series, the authors identified patterns requiring adjunctive rhinoplasty in the setting of orthognathic surgery. The authors present an algorithm to extensively treat the nasomaxillofacial relationship using orthognathic surgery alone, orthognathic surgery in concert with rhinoplasty, or orthognathic surgery followed by staged rhinoplasty.

A 3-Dimensional Analysis of Nasal Cavity Volume After Maxillary Le Fort I Osteotomy

Two- and 3-dimensional studies on changes of the pharyngeal airway after a Le Fort I osteotomy have been conducted, but there are few studies on the change of nasal structure. The nasal cavity is the first passage through which air enters during respiration. Movement of the maxilla by Le Fort I osteotomy affects the shape of the nasal cavity and the shape of other parts of the airway. This study compared preoperative and postoperative changes of the nasal cavity volume after a maxillary Le Fort I osteotomy. Pre- and postoperative computed tomograms of 32 patients were assessed for nasal cavity volume according to the direction of maxillary movement. Thirty-two patients (22 men and 10 women) were classified according to the direction of maxillary movement: maxillary impaction (group I; 8 men and 6 women) and maxillary impaction and advancement (group II; 14 men and 4 women). Nasal cavity volume was markedly decreased after the Le Fort I osteotomy in groups I and II. Group I showed a positive correlation between the ratio of impaction and the ratio of volume difference. Group II showed no correlation between the ratio of impaction or advancement and the ratio of volume difference. Impaction and advancement of the maxilla decreased nasal volume.

Changes in maxillofacial morphology and velopharyngeal function with two-stage maxillary distraction–mandibular setback surgery in patients with cleft lip and palate

Maxillary distraction is increasingly used for the correction of severe maxillary retrusion in patients with cleft lip and palate. However, control of the maxillary movement is difficult, and the need to wear visible distractors for a long period of time causes psychosocial problems. A two-stage surgical approach consisting of maxillary distraction and mandibular setback was developed to overcome these problems. In this study, changes in maxillofacial morphology and velopharyngeal function were examined in 22 patients with cleft lip and palate who underwent this two-stage approach. Lateral cephalograms taken just before the first surgery, immediately after the second surgery, and at completion of the active post-surgical orthodontic treatment were used to examine maxillofacial morphology. Velopharyngeal function was evaluated by speech therapists using a 4-point scale for hypernasality. The average forward movement of the maxilla with surgery at point A was 7.5mm, and the average mandibular setback at pogonion was 8.6mm. The average relapse rate during post-surgical orthodontic treatment was 25.2% for the maxilla and 11.2% for the mandible. After treatment, all patients had positive overjet, and skeletal relapse was covered by tooth movement during postoperative orthodontics. Velopharyngeal function was not changed by surgery. This method can shorten the period during which the distractors have to be worn and reduce the patient burden.

The accuracy of maxillary positioning using digital model planning and 3D printed wafers in bimaxillary orthognathic surgery.

Orthognathic wafers may be made using digital model movements and CAD-CAM technology. This paper analysed the accuracy of maxillary movements using this new process. Retrospective study of pre and post-operative cephalograms. Thirty consecutive orthognathic patients undergoing bimaxillary osteotomies in a UK hospital. Jaw movements were planned using cephalometric and Orthoanalyzer™ software. The resultant intermediate and final wafer occlusal relationships were used for wafer fabrication by 3D printing of the inter-occlusal space. Pre- and post-operative lateral cephalograms were compared in terms of maxillary antero-posterior and vertical movements. Statistical analyses including the paired t-test, two-sample t-test and Fisher's exact test. Wide individual variation was observed between the planned and actual movements. Thirteen cases (43%) had a 2 mm discrepancy in at least one variable. Statistically significant differences between the planned and actual maxillary vertical movements were observed for the molar (U6y: p < 0.0001) and anterior maxillary (Ay: p < 0.01) differences. Analysis of a subgroup with primarily impaction movements demonstrated a statistically significant bias towards excessive maxillary advancement (U1x: p < 0.01) and incisor impaction (U1y: p < 0.01) in this group. This new digital surgical wafer technique achieves a similar level of accuracy to the conventional facebow and model surgery process.

Nasal Soft Tissue Change Following Bimaxillary Orthognathic Surgery.

The purpose of this study is to identify the correlation between maxillary movement and nasal soft tissue changes on three-dimensional reconstructed cone beam computed tomography (CBCT) images after Le Fort I osteotomy. The authors also investigate the long-term change of alar base width (ABW) to determine the effect of cinch suture. The authors retrospectively studied 52 subjects (14 males and 38 females) who were treated by bimaxillary orthognathic surgery including Le Fort I osteotomy and mandibular ramus surgery. The landmarks and planes were established on three-dimensional reconstructed CBCT images. The authors measured each parameters preoperatively, 1 month postoperatively, and 1 year postoperatively. There was no significant correlation between the horizontal movement of A-point and the widening of ABW (P < 0.038), nor was there a significant correlation between the vertical movement of A-point and the change of ABW (P < 0.61). There was no significant correlation between horizontal and vertical movement of anterior nasal spine and the widening of ABW, nor was there a significant correlation between the nasal tip length and the vector of maxillary movement. There was no significant correlation between the ABW widening and the vector of surgical maxillary movement. The effect and stability of the alar base cinch suture is difficult to determine and require further investigation.