Dentofacial Deformity Patients Research Articles

Deep learning classification performance for diagnosing condylar osteoarthritis in patients with dentofacial deformities using panoramic temporomandibular joint projection images.

The present study aimed to assess the consistencies and performances of deep learning (DL) models in the diagnosis of condylar osteoarthritis (OA) among patients with dentofacial deformities using panoramic temporomandibular joint (TMJ) projection images. A total of 68 TMJs with or without condylar OA in dentofacial deformity patients were tested to verify the consistencies and performances of DL models created using 252 TMJs with or without OA in TMJ disorder and dentofacial deformity patients; these models were used to diagnose OA on conventional panoramic (Con-Pa) images and open (Open-TMJ) and closed (Closed-TMJ) mouth TMJ projection images. The GoogLeNet and VGG-16 networks were used to create the DL models. For comparison, two dental residents with < 1year of experience interpreting radiographs evaluated the same condyle data that had been used to test the DL models. On Open-TMJ images, the DL models showed moderate to very good consistency, whereas the residents' demonstrated fair consistency on all images. The areas under the curve (AUCs) of both DL models on Con-Pa (0.84 for GoogLeNet and 0.75 for VGG-16) and Open-TMJ images (0.89 for both models) were significantly higher than the residents' AUCs (p < 0.01). The AUCs of the DL models on Open-TMJ images (0.89 for both models) were higher than the AUCs on Closed-TMJ images (0.72 for both models). The DL models created in this study could help residents to interpret Con-Pa and Open-TMJ images in the diagnosis of condylar OA.

Pre- and Post-Operative Cone Beam Computed Tomography Assessment of the Temporomandibular Joint in Patients with Orthognathic Surgery.

This study aimed to compare the pre- and post-operative temporomandibular joint (TMJ) condylar position in dentofacial deformity (DFD) patients who had orthognathic surgeries using cone beam computed tomography (CBCT). A retrospective study evaluating the pre- and post-operative CBCT for 79 DFD patients (equivalent to 158 TMJs) (mean age = 26.62 ± 9.5 years) with a bilateral sagittal split osteotomy with or without Le Fort I surgeries (n = 29 Class II DFD, n = 50 Class III DFD) was performed. This included the compartmental measurement of TMJ spaces, in addition to the measurement of intercondylar distances and angles. Condylar position centricity was assessed using the Pullinger and Hollender formula. Clinical data were analysed for DFD class, the type of surgery and post-operative CBCT timing. Pre- and post-operative measurements were compared statistically using a paired t-test, Wilcoxon signed-rank test, and Stuart-Maxwell test. TMJ condyles tended to relocate post-operatively in a posterosuperior position with internal rotation in Class II DFD and a superior position with internal rotation in Class III DFD. However, the overall changes were within <0.5 mm translation and <4° rotation and the number of concentrically positioned condyles (according to the Pullinger and Hollender formula) did not change significantly. Orthognathic surgery is associated with minor post-operative translational and rotational condylar positional changes in Class II and III DFDs.

Associations between temporomandibular disorders, pain, jaw and masticatory function in dentofacial deformity patients: A cross-sectional study.

Patients with dentofacial deformity often present with impaired masticatory function, orofacial pain and temporomandibular disorders (TMD). This study investigates the relationship between TMD, pain, jaw and masticatory function at different stages of orthognathic surgical (OS) treatment. A total of 120 OS patients were prospectively recruited and grouped as pre-orthodontic (group 1), pre-surgery (group 2), 4-month post-surgery (group 3), 24-month post-surgery (group 4), in addition to 30 controls (group 0). Outcomes were assessed using: Jaw Function Limitation Scale (JFLS), McGill pain questionnaire, DC/TMD instrument, voluntary maximum bite force (MVBF), and masticatory efficiency (ME) using two-coloured chewing gum. Data were analysed using structural equation modelling. The prevalence of non-painful TMD did not differ between groups (p = .827). However, the prevalence of painful TMD differed between groups (p = .001). Among the painful TMDs, the highest prevalence was observed for masseter myalgia in group 2 (p = .031), and importantly group 4 did not differ from group 0 (p = .948). The MPQ score was significantly higher in group 1 (p = .001) compared to group 0, and the JFLS score was significantly higher in groups 1, 2 and 3 compared to group 0. Notably, MPQ (p = .756) and JFLS (p = .572) scores in group 4 were not different from group 0. However, MVBF (p = .996) and ME (p = .991) did not differ between groups 1 and 4. The association of self-reported pain and jaw function with the masticatory function was observed in OS patients. OS was not associated with a negative impact on TMD. Jaw function and pain levels were similar to controls at the 24-month follow-up. The masticatory function was further affected by the surgery and seems to require a longer recovery time. Moreover, it was confirmed that pain and TMD were associated with limitations in jaw function and impacts on masticatory function.

Changes in condylar position after orthognathic surgery and its correlation with temporomandibular symptoms (TMD)- a prospective study

The aim of the study was to assess the changes in the condylar position after orthognathic surgery (OGS) and its effect on temporomandibular disorders (TMD). A total of 37 dentofacial deformity patients included in the study who had undergone OGS were divided into three groups: Group I, Le Fort I maxillary advancement; Group II, bilateral sagittal split osteotomy (BSSO) mandibular advancement ± Le Fort I; and Group III, BSSO mandibular setback ± Le Fort I. Patients were evaluated clinically using Diagnostic Criteria for TMD and by radiography preoperatively and 6 months postoperatively. The positional changes in condyle were correlated with signs and symptoms of TMD. A total of 37 patients in three groups (Group I, 8 patients; Group II, 10 patients; and Group III, 19 patients) were evaluated. Overall, condyles had anterio-medio-inferior movement with 7 of 8 patients in Group I, 6 of 10 patients in Group II and 13 of 19 patients in Group III having ≤2 mm displacement. In angular changes, inward-anterio-medial movement was observed with 6 of 8 patients in Group I; about 5 of 10 patients, and 10 of 19 patients in Group II and III respectively had ≤5° change. Intragroup and intergroup comparisons showed insignificant changes in TMD and linear/angular movement (p ≥ 0.05). Pearson correlation coefficient was found to be nonsignificant on the radiographic and clinical comparison (p ≥ 0.05). Intrarater reliability (Kappa value) was found to be 0.83, confirming the results. Within the limitations of the study it seems that there are minimal linear and angular changes in condyle after orthognathic surgery that were not responsible for the development of temporomandibular disorders in the postoperative course.

Impacts of Skeletal Anterior Open Bite Malocclusion on Speech.

Articulation problems are seen in 80-90% of dentofacial deformity (DFD) subjects compared with 5% of the general population, impacting communication and quality of life, but the causal link is unclear. We hypothesize there are both qualitative (perceptual) and quantitative (spectral) differences in properties of stop (/t/ or /k/), fricative (/s/ or /∫/), and affricate (/t∫/) consonant sounds and that severity of anterior open bite (AOB) jaw disharmonies correlates with degree of speech abnormality. To test our hypotheses, surgical orthodontic records and audio recordings were collected from DFD patients (n=39 AOB, 62 controls). A speech pathologist evaluated subjects and recordings were analyzed using spectral moment analysis (SMA) to measure sound frequency distortions. Perceptually, there is a higher prevalence of auditory and visual speech distortions in AOB DFD patients when compared to controls. Quantitatively, a significant (p<0.01) increase in the centroid frequency (M1) was seen in the /k/, /t/, /t∫/, and /s/ sounds of AOB subjects compared to the controls. Using linear regression, correlations between AOB skeletal severity and spectral distortion were found for /k/ and /t/ sounds. A higher prevalence of qualitative distortion and significant quantitative spectral distortions in consonant sounds were seen in AOB patients compared to controls. Additionally, severity of skeletal AOB is correlated with degree of distortion for consonant sounds. These findings provide insight into how the surgical and/or orthodontic treatment of AOB may impact speech.

Three-Dimensional Cephalometric Landmarking and Frankfort Horizontal Plane Construction: Reproducibility of Conventional and Novel Landmarks.

In some dentofacial deformity patients, especially patients undergoing surgical orthodontic treatments, Computed Tomography (CT) scans are useful to assess complex asymmetry or to plan orthognathic surgery. This assessment would be made easier for orthodontists and surgeons with a three-dimensional (3D) cephalometric analysis, which would require the localization of landmarks and the construction of reference planes. The objectives of this study were to assess manual landmarking repeatability and reproducibility (R&R) of a set of 3D landmarks and to evaluate R&R of vertical cephalometric measurements using two Frankfort Horizontal (FH) planes as references for horizontal 3D imaging reorientation. Thirty-three landmarks, divided into “conventional”, “foraminal” and “dental”, were manually located twice by three experienced operators on 20 randomly-selected CT scans of orthognathic surgery patients. R&R confidence intervals (CI) of each landmark in the -x, -y and -z directions were computed according to the ISO 5725 standard. These landmarks were then used to construct 2 FH planes: a conventional FH plane (orbitale left, porion right and left) and a newly proposed FH plane (midinternal acoustic foramen, orbitale right and left). R&R of vertical cephalometric measurements were computed using these 2 FH planes as horizontal references for CT reorientation. Landmarks showing a 95% CI of repeatability and/or reproducibility > 2 mm were found exclusively in the “conventional” landmarks group. Vertical measurements showed excellent R&R (95% CI < 1 mm) with either FH plane as horizontal reference. However, the 2 FH planes were not found to be parallel (absolute angular difference of 2.41°, SD 1.27°). Overall, “dental” and “foraminal” landmarks were more reliable than the “conventional” landmarks. Despite the poor reliability of the landmarks orbitale and porion, the construction of the conventional FH plane provided a reliable horizontal reference for 3D craniofacial CT scan reorientation.

Determinants of Upper Lip Form: An Analysis Using Geometric Morphometrics

Orthodontics and orthognathic surgery can alter an individual's facial form, and it is the clinician's goal to predictably control changes in the facial soft tissues to achieve treatment goals. Within the facial profile, controlling projection of certain structures, such as the chin, is predictable, as the soft-tissue response to hard-tissue changes in such areas is predictable. The upper lip, on the other hand, presents a different challenge. While multiple studies have shown relationships between advancement of the upper incisor and advancement of the soft-tissue lip, unlike the chin, the anterior position of the upper lip is only a small component of upper-lip profile esthetics. Given the structure of the upper lip, the angulation plays a prominent role in upper-lip profile esthetics besides just its anteroposterior projection. No direct or indirect relationships have been established between the maxillary incisal orientation and upper-lip angulation. The clinical significance in understanding the upper lip to hard-tissue relationship is to predictably control the upper-lip angulation in orthodontics and/or orthognathic surgery in patients with dentofacial deformities. In the absence of reliable data, planning often becomes overly subjective or arbitrary, which could lead to poor esthetic outcomes. To the author's knowledge, there are no studies that analyze the relationship between the hard tissues and the upper-lip angulation. This is presumably the case because of the difficulty in comparing the contours of the hard and soft tissues in these non-linear structures. Any “parallelism” cannot be reliably measured in a reliable or quantitative way using conventional cephalometric or other linear techniques.A retrospective cross-sectional study was designed to analyze cone beam computerized tomography (CBCT) scans from 104 patients, using geometric morphometrics. The contour of the hard tissue was evaluated by taking a point below anterior nasal spine (ANS) at the point of greatest convexity between ANS and maxillary alveolus, as well as the most anterior point of the maxillary alveolar bone between the central incisors. Once these points were identified, 3 semi-landmarks were taken at equidistant points between these in order to best trace the curvature of this area. For the soft-tissue analysis, subnasale and labrale superioris were identified and, once again, 3 semi-landmarks were taken at equidistant points between these landmarks to map the upper-lip curvature.The data were then compiled, giving a total of 1040 data points, 520 hard-tissue and 520 soft-tissue points. While the results of the principal components analysis and partial least squares are pending, the initial data show a positive correlation between contour of the alveolar bone and teeth and the upper-lip position and form.Based on these findings, it appears that the upper-lip contour in the dentofacial deformity patient can be predictably controlled by manipulating the position of the maxillary alveolus and incisor position via orthodontic and surgical means.

Effect of Orthognathic Surgery on Temporomandibular Disorders: A Prospective Study.

The relationship of orthognathic surgery and temporomandibular disorders (TMD) has always been a topic of debate. The results have varied from mild/moderate improvement to actual worsening in some cases. The purpose of this study was to evaluate the effects of orthognathic surgery on TMD in patients with dentofacial deformities. An observational study was conducted on 56 patients (112 condyles) of patients with dentofacial deformities with age range of 19-35years who underwent orthognathic surgery. TMD was evaluated using seven types of disorders in diagnostic criteria for TMD (DC/TMD, 2010) pre-operatively and after 6-month follow-up. There was minimal decrease in unassisted mouth opening without pain, maximum unassisted mouth opening and maximum assisted mouth opening after surgery. There was significant improvement in joint sounds and headache in 18 patients. Overall, there was improvement in 29 cases (33.93%), worsening in 8 cases (14.29%) and no change in 19 cases (33.93%). There was high prevalence of TMDs in dentofacial deformity patients. Most of the patients with pre-operative TMD improved with orthognathic surgery, whereas a small percentage of patients who were asymptomatic pre-operatively developed TMD after surgery and in some patients TMD worsened. The risk of developing TMD and worsening of severity conditions is low.

Complications of Poly-l-Lactic Acid and Polyglycolic Acid (PLLA/PGA) Osteosynthesis Systems for Maxillofacial Surgery: A Retrospective Clinical Investigation.

Two second-generation PLLA/PGA bioresorbable osteosynthetic plate systems for oral and maxillofacial surgery are available in Japan. The two systems have different PLLA-PGA component ratios (RapidSorb®, 85:15; Lactosorb®, 82:18) and plate and screw shapes. We conducted a retrospective study to compare our clinical evaluation and examine the incidence of postoperative complications between the two plate systems. A retrospective survey was conducted in 148 patients (midfacial fracture/trauma (68.2%) and dentofacial deformity patients (31.8%); males (54.7%); median age, 37.5 years) treated using maxillofacial osteosynthetic plate systems. The complications included plate exposure (7.4%), infection, (2.7%), and plate breakage (0.7%). Multivariate logistic regression analysis showed a significant correlation between sex (female), plate system (Lactosorb®), number of plates, and pyriform aperture and periorbital sites of plate placement (p < 0.05). Additionally, the propensity score-adjusted model showed a significant correlation between Lactosorb® and postoperative complications (odds ratio 1.007 (95% confidence interval, 1.001–1.055), p < 0.01). However, the two plate systems showed a low incidence rate of complications, and the plate integration and survivability were similar using 2.0-mm or 1.5-mm resorbable plate regardless of the plate system. Our findings suggest that female sex and a greater number of plates are risk factors for postoperative complications, whereas pyriform aperture and periorbital plate placements reduce the risk.

Surgical/Orthodontic Correction of Transverse Maxillary Discrepancies.

The transverse dimension is a critical component of comprehensive treatment in orthognathic surgery. Several treatment approaches exist and the team must consider the patient's needs, desires, and limitations when working to correct the malocclusion. Treatment approaches may include only orthodontic expansion or rapid palatal orthodontic expansion; however, in adults, the orthodontist may require surgical assistance to expand the bony maxilla. Segmental maxillary expansion may be indicated in severe transverse deficiencies of the maxillary arch or dentofacial deformity patients also requiring vertical and sagittal corrections. The various treatment options, advantages, and disadvantages, and indications for each surgical approach are discussed.

Orthognathic Surgery Has a Significant Positive Effect on Perceived Personality Traits and Perceived Emotional Facial Expressions in Subjects With Primary Mandibular Deficiency.

This study tested the hypothesis that a layperson's social perceptions of a dentofacial deformity (DFD) patient with primary mandibular deficiency (PMD) are more positive after bimaxillary orthognathic surgery.A survey was implemented comparing layperson's social perceptions of emotional expressions and personality traits before and >6 months after orthognathic surgery when viewing standardized facial photographs. The study sample comprised 20 patients selected randomly from a larger primary mandibular deficiency database, treated by 1 surgeon after orthognathic surgery. The outcome variable was change in 6 perceived emotional expressions and 6 personality traits studied. Descriptive and bivariate statistics were computed (P < .05).Five hundred respondents (raters) completed the survey. The respondents were 52% male with 44% aging from 25 to 34. After bimaxillary and chin orthognathic surgery, primary mandibular deficiency patients were perceived to be significantly more dominant, trustworthy, friendly, intelligent, attractive, and less threatening (P < .05). They were also perceived as happier and less angry, surprised, sad, afraid, or disgusted than before surgery (P < .05).Laypeople consistently report improved social traits in primary mandibular deficiency patient's perceived emotional expressions and perceived personality traits after bimaxillary and chin orthognathic surgery.

Effect of sagittal split ramus osteotomy on morphologic parameters of temporomandibular joint in patients with mandibular prognathism.

The purpose of this study was to evaluate the change in three-dimensional morphology and clinical symptoms of temporomandibular joint (TMJ) in class III dentofacial deformity patients postoperatively for 6 months after sagittal split ramus osteotomy (SSRO).Seventeen patients with skeletal Class III malocclusion and 10 asymptomatic volunteers (classified as Control group) were recruited for the study and underwent cone-beam computed tomography scanning. The geometries of the maxilla and mandible were reconstructed using MIMICS (Materialise, Leuven, Belgium). The morphologic measurements of the patients’ TMJs were done before surgery and at 6-month follow-up – named as Pre and Post groups, respectively.The joint spaces (medial joint space, superior joint space, lateral joint space, anterior joint space, and posterior joint space) of the Control group were significantly greater than those of the Pre and Post groups (P < .05), and SSRO did not significantly change the TMJ morphology parameters. Five patients were found to have preoperative temporomandibular disorder (TMD) symptoms, and 3 of them were relieved at 6 months after surgery. Postoperative TMD symptom was observed in 1 patient without preoperative TMD symptom.SSRO did not markedly alter the TMJ morphology of the patients with mandibular prognathism. The effects of SSRO on TMD symptoms should be related to the type of deformity.

Orthognathic Surgery Has a Significant Positive Effect on Perceived Personality Traits and Perceived Emotional Facial Expressions in Subjects with Primary Maxillary Deficiency.

Background:Crowdsourcing is increasingly being used in medical research to obtain the opinion of laypeople. The investigators hypothesized that a layperson’s perception of a primary maxillary deficiency (PMD) dentofacial deformity (DFD) patient is more favorable after orthognathic surgery with regard to perceived personality traits and emotional facial expressions.Methods:The investigators implemented a survey, distributed through Amazon.com’s Mechanical Turk crowdsourcing platform, to compare 6 perceived personality traits and 6 perceived emotional traits before and >6 months after orthognathic surgery in subjects through standardized facial photographs. The sample was composed of 20 subjects randomly selected from a PMD DFD database, treated by 1 surgeon all having undergone bimaxillary and chin orthognathic surgery. The outcome variable was change in each of 6 perceived personality and 6 emotional expression traits studied. Descriptive and bivariate statistics were computed. P-value of <0.05 was considered significant.Results:Five hundred respondents (raters) completed the survey. A majority of respondent raters were male (59%) and White (71%), ranging in age between 25 and 34 years (52%). After bimaxillary and chin orthognathic surgery, PMD subjects as a group were perceived to be significantly more dominant, more trustworthy, more friendly, more intelligent, more attractive, and less threatening. They were also perceived as happier and less angry, less surprised, less sad, less afraid, and less disgusted than before surgery (P < 0.05).Conclusions:We confirmed that laypeople consistently report positive changes in a PMD DFD subject’s perceived personality traits and perceived emotional expressions after bimaxillary and chin orthognathic surgery.

Changes in head posture, hyoid bone position and airway dimensions after orthognatic surgery

Mandibular/bimaxillary advancement surgery is described as a potential means of increasing the oropharyngeal airspace , provided a significant improvement in breathing capacity. Aim: To evaluate postural changes suffered in the positioning of the head and the hyoid bone, dentofacial deformity patients undergoing orthognathic surgery with consequent dimensional changes of oropharyngeal airspace. Methods: We evaluated the archived records of patients with postoperative 6 months minimum, being used as criteria for selecting individuals with dental class II malocclusion and facial Pattern II, jaw or maxilomandibular deficiency, patients undergoing orthodontic-surgical treatment through mandibular advancement or of both bony bases, associated or not to genioplastia. Twenty-eight patients were part of the sample and were evaluated by means of lateral radiographs in lateral standard digitized, in three distinct periods: pre-operative, immediate postoperative period and late postoperative period (minimum 6 months). 12 linear measures and two angular cephalometric analysis were used in this research. Results: With the surgery, there was an average of mandibular advancement 6, 76 mm, while remaining stable in the long-term follow-up period; the hyoid bone moved onward and upward, extending your movement in the post-operative. The cervical region presented minimal movement of the head extension in the immediate post operative with almost total returns the position of the head in the post-operative. The surgical movement of oropharyngeal air space was in the same direction of the mandibular movement, but to a lesser extent (1,88 -2,76 mm). In the post-operative period was a late partial reduction of the diameter of the air space between 34-56% of gain, representing an apparent accommodation of this anatomical region soft tissue. Conclusion: Orthognathic surgery of mandibular advancement or bimaxillary promotes significant changes in aesthetics, in the position of the hyoid bone and upper airway dimensions, getting better quality of life to these patients.

Large-Scale Study of Long-Term Anteroposterior Stability in a Surgery-First Orthognathic Approach Without Presurgical Orthodontic Treatment.

Presurgical orthodontic treatment has long been known as a prerequisite in the traditional orthognathic approach. However, achieving ideal decompensation is very difficult even in the presurgical orthodontic period. For minimization of this problem, the surgery-first orthognathic concept has been introduced. The authors hypothesized that this treatment modality will be feasible for skeletal class III dentofacial deformity patients. In this study, the authors tried to compare the traditional and surgery-first approaches regarding long-term outcomes in terms of stability, based on large-scale data. The patients included in this study had skeletal class III dentofacial deformities, and all underwent, and completed, orthognathic surgery between December 2007 and December 2015. The inclusion criteria were based on presurgical simulation on the dental model, and the authors predicted the potential of the surgery-first approach by this preoperative simulation model. Patients with cleft-related syndromes, those who underwent orthognathic surgeries due to facial asymmetry or class II deformity were excluded from the study. In total, 104 class III patients were enrolled in the surgery-first group and 51 class III patients in the traditional orthodontic-first group. Satisfactory results were achieved in all 155 patients with dentofacial deformity in this study. Overall, the analysis revealed that anteroposterior skeletal long-term stability in the surgery-first approach was not different, statistically or otherwise, from that in the orthodontic-first approach. Anteroposterior skeletal stability was maintained well in the surgery-first approach. In conclusion, surgery-first approach without presurgical orthodontic treatment can achieve similar results of long-term anteroposterior stability in correcting dentofacial deformities as the orthodontic treatment-first approach.

“Silent” Sleep Apnea in Dentofacial Deformities and Prevalence of Daytime Sleepiness After Orthognathic and Intranasal Surgery

The purposes of this study were to determine the occurrence of undiagnosed "silent" obstructive sleep apnea (OSA) in dentofacial deformity (DFD) patients at initial surgical presentation and to report on the level of daytime sleepiness in DFD patients with OSA and chronic obstructive nasal breathing (CONB) after undergoing bimaxillary, chin, and intranasal surgery. A retrospective cohort study of patients with a bimaxillary DFD and CONB was implemented. Patients were divided into those with no OSA (group I) and those with OSA (group II). Group II was further subdivided into patients referred with polysomnogram (PSG)-confirmed OSA (group IIa) and those with a diagnosis of OSA only after surgical consultation, airway evaluation, and a positive PSG (group IIb). Group II patients were analyzed at a minimum of 1year after surgery (range, 1 to 10years) for daytime sleepiness with the Epworth Sleepiness Scale.Patients with postoperative excessive daytime sleepiness were assessed for risk factors and continued need for OSA treatment. Patients in group II were studied to determine which DFD patterns were most associated with OSA. We compared the prevalence of OSA between our study population and the general population. Two hundred sixty-two patients met the inclusion criteria. Of these, 23% (60 of 262) had PSG-confirmed OSA (group II). This rate was much higher than that found in the general population. Of the patients, 7% (19 of 262) were known to have OSA at initial surgical consultation (group IIa). An additional 16% (41 of 262) were later confirmed by PSG to have OSA (group IIb). Patients with primary mandibular deficiency and short face DFDs were most likely to have OSA (P<.001 and P=.001, respectively).In group II, 91% (55 of 60) rated their daytime sleepiness as "not sleepy" at a minimum of 1year after surgery. A significant association was found between group II patients with postoperative excessive daytime sleepiness ("sleepy" or "very sleepy") and a preoperative body mass index category of overweight (P=.026). Our study found silent OSA to be frequent in the DFD population. The prevalence of OSA in DFD patients exceeded that estimated in the general population, with retrusive jaw patterns most affected. In DFD patients also presenting with OSA and CONB, we confirmed low levels of daytime sleepiness long-term after simultaneous bimaxillary orthognathic, chin, and intranasal surgery.

Morbidity and Mortality Rates After Maxillomandibular Advancement for Treatment of Obstructive Sleep Apnea

To compare morbidity and mortality rates in obstructive sleep apnea (OSA) versus dentofacial deformity (DFD) patients undergoing equivalent maxillofacial surgical procedures. Patients with OSA who underwent maxillomandibular advancement with genial tubercle advancement in the Massachusetts General Hospital Department of Oral and Maxillofacial Surgery from December 2002 to June 2011 were matched to patients with DFD undergoing similar maxillofacial procedures during the same period. They were compared regarding demographic variables, medical comorbidities, perioperative management, intraoperative complications, early and late postoperative complications, and mortality rate. A study group of 28 patients with OSA and a control group of 26 patients with DFD were compared. The patients with OSA were older (41.9 ± 12.5years vs 21.7 ± 8.6years), had a higher American Society of Anesthesiologists classification (2.0 ± 0.5 vs 1.3 ± 0.6), and had a higher body mass index (29.6 ± 4.7kg/m(2) vs 23.0 ± 3.1kg/m(2)). They also had a greater number of medical comorbidities (2.4 ± 2.3 vs 0.7 ± 1.0). More OSA patients than DFD patients had complications (28 [100%] vs 19 [73%], P=.003), and the total number of complications in the OSA group was higher (108 vs 33, P < .001). Of the complications, 13.9% in the OSA group and 3.0% in the DFD group were classified as major. The absolute risk of a complication was 3.9 for the OSA group versus 1.3 for the DFD group. The relative risk of complications in OSA patients compared with DFD patients was 3.0. No difference in mortality rate was found. The patients in the OSA group were older, had more comorbidities, and ultimately had a greater number of early, late, minor, and major complications than those in the DFD group. The incidence of death in both groups was zero. Maxillomandibular advancement appears to be a safe procedure regarding mortality rate, but OSA patients should be counseled preoperatively regarding the relative increased risk of complications.

Assessment of metal artifacts in three-dimensional dental surface models derived by cone-beam computed tomography.

ObjectiveThe aim of this study was to assess artifacts induced by metallic restorations in three-dimensional (3D) dental surface models derived by cone-beam computed tomography (CBCT).MethodsFifteen specimens, each with four extracted human premolars and molars embedded in a plaster block, were scanned by CBCT before and after the cavitated second premolars were restored with dental amalgam. Five consecutive surface models of each specimen were created according to increasing restoration size: no restoration (control) and small occlusal, large occlusal, disto-occlusal, and mesio-occluso-distal restorations. After registering each restored model with the control model, maximum linear discrepancy, area, and intensity of the artifacts were measured and compared.ResultsArtifacts developed mostly on the buccal and lingual surfaces. They occurred not only on the second premolar but also on the first premolar and first molar. The parametric values increased significantly with increasing restoration size.ConclusionsMetallic restorations induce considerable artifacts in 3D dental surface models. Artifact reduction should be taken into consideration for a proper diagnosis and treatment planning when using 3D surface model derived by CBCT in dentofacial deformity patients.

顎変形症の診断と手術手技 －その基本と勘どころ－

顎変形症の診断と手術手技 －その基本と勘どころ－

Maxillary Yaw as the Primary Predictor of Maxillary Dental Midline Deviation: 3D Analysis Using Cone-Beam Computed Tomography

The purpose of this study was to investigate which factors affect upper dental midline deviation in dentofacial deformity patients using cone-beam computed tomography analysis. Twenty-eight patients were selected for this study. Subjects were divided into 2 groups according to the amount of upper incisor (U1) midline deviation from the clinical facial midline: group 1 (U1 deviation <2 mm) and group 2 (U1 deviation >2 mm). Linear measurements, angles, and reference planes on 3-dimensional (3D) computed tomograms were obtained. The predictor variables were maxillary yaw, palatal plane angle, differences of maxillary point to the coronal and sagittal planes, and maxillary canting. The outcome variable was U1 deviation. The variables between the 2 groups and 2 sides were analyzed with a t test. Pearson correlation coefficient and multiple regression analysis were also calculated within each group for each measurement against the U1 deviation to determine which variables affect U1 deviation. P < .05 was considered statistically significant. The patients were evenly distributed between each group (n = 14 in each group). There was significant deviation of U1 from the sagittal plane in group 2 compared with group 1 (0.99 mm in group 1 vs 1.73 mm in group 2, P < .05). When we compared yaw with the sagittal plane, group 2 was more rotated than group 1 (1.16° in group 1 vs 2.28° in group 2, P < .01). Through multiple regression analysis, the primary predictor variable for U1 deviation was maxillary yaw (P < .05). This study suggests that maxillary yaw is the primary contributing factor for upper dental midline deviation. The use of maxillary yaw should be considered when one is performing orthognathic surgery in patients with U1 deviation to achieve optimum esthetics.