Assessment of the maxilla-mandible-nasion angle in normal and aneuploid foetuses in the first trimester of pregnancy.

PURPOSE: This retrospective study aims to determine whether the maxilla-mandible-nasion (MMN) angle can be reliably measured in the first trimester, to describe normal ranges, and to determine if significant changes occur in foetuses with aneuploidies. METHODS: The MMN angle was measured in stored 2D-ultrasound images of 200 normal fetal profiles between 11+0 and 13+6 weeks of gestation. Each image was analyzed by two observers at two independent time points. Bland-Altmann analysis was performed to evaluate the reliability of the measurements. Additionally, the MMN angle was measured on sonograms from 140 aneuploid foetuses. RESULTS: The mean MMN angle in normal foetuses from 11 to 14 weeks of gestation was 15.4°. Reliability of the measurement was high when repeatedly measured by the same observer (ICC = 0.92 and 0.82) and between two observers (ICC = 0.77 and 0.63). Average MMN values in foetuses with trisomy 21, 13, and Turner syndrome were significantly higher than those measured in normal foetuses. The highest differences were observed in foetuses with trisomy 13. Among those, 62% had an MMN angle above the 95th percentile and 92% above the normal mean. CONCLUSION: The MMN angle can be reliably measured in early pregnancy and is abnormal in about 60% of foetuses with trisomy 13.

Whole-exome sequencing identified compound heterozygous variants in ROR2 gene in a fetus with Robinow syndrome.

BACKGROUND: Autosomal recessive Robinow syndrome (ARRS) is a rare genetic disorder, which affects the development of multiple systems, particularly the bones. OBJECTIVES: The aim of this study was to investigate the genetic cause of a ARRS fetus and to evaluate the reliability of whole-exome sequencing (WES) in prenatal diagnosis on cases with indistinguishable multiple malformation. METHODS: Clinical and ultrasonic evaluations were conducted on the fetus, and multiplatform genetic techniques were used to identify the variation responsible for RS. The pathogenicity of the novel variation was evaluated by in silico methods. Western blotting (WB) and immunohistochemistry (IHC) were performed on fetal tissues after the fetus' stillbirth and postabortal autopsy. RESULTS: A compound heterozygous variation consisting c.613C > T and c.904C > T in ROR2 gene was identified. In silico prediction suggested that c.904C > T was a deleterious variant. IHC result demonstrated that ror2 expression level of the proband in osteochondral tissue significantly increased comparing with that of the control sample. CONCLUSIONS: For the first time in Chinese population, we characterized a novel variation in ROR2 gene causing ARRS. This study extended the mutation spectrum of ARRS and provided a promising strategy for prenatal diagnosis of cases with ambiguous multiple deformities.

A New Software Suite in Orthognathic Surgery : Patient Specific Modeling, Simulation and Navigation.

Orthognathic surgery belongs to the scope of maxillofacial surgery. It treats dentofacial deformities consisting in discrepancy between the facial bones (upper and lower jaws). Such impairment affects chewing, talking, and breathing and can ultimately result in the loss of teeth. Orthognathic surgery restores facial harmony and dental occlusion through bone cutting, repositioning, and fixation. However, in routine practice, we face the limitations of conventional tools and the lack of intraoperative assistance. These limitations occur at every step of the surgical workflow: preoperative planning, simulation, and intraoperative navigation. The aim of this research was to provide novel tools to improve simulation and navigation. We first developed a semiautomated segmentation pipeline allowing accurate and time-efficient patient-specific 3D modeling from computed tomography scans mandatory to achieve surgical planning. This step allowed an improvement of processing time by a factor of 6 compared with interactive segmentation, with a 1.5-mm distance error. Next, we developed a software to simulate the postoperative outcome on facial soft tissues. Volume meshes were processed from segmented DICOM images, and the Bullet open source mechanical engine was used together with a mass-spring model to reach a postoperative simulation accuracy <1 mm. Our toolset was completed by the development of a real-time navigation system using minimally invasive electromagnetic sensors. This navigation system featured a novel user-friendly interface based on augmented virtuality that improved surgical accuracy and operative time especially for trainee surgeons, therefore demonstrating its educational benefits. The resulting software suite could enhance operative accuracy and surgeon education for improved patient care.

Comparative Study of Mandible Ramus Morphology Using 3-dimensional CT in Sagittal Split Ramus Osteotomy.

The purpose of the present study was to investigate the relevance of the external morphology of the mandibular ramus, internal bone tissue structure, and maxillofacial morphology at the site for sagittal split ramus osteotomy among different facial skeletal patterns. A total of 80 patients with jaw deformities who underwent sagittal split ramus osteotomy were included in the study. The patients were divided into two groups based on facial skeletal type (skeletal Class II or skeletal Class III). A further 7 patients with no skeletal abnormalities were established as the control group (skeletal Class I). Computed tomography images obtained from these patients were 3-dimensionally reconstructed and the morphology of the mandibular ramus determined. Thickness at the mandibular foramen in Class II was greater than that in Class III, and showed the lowest value at the midpoint of the mandibular foramen and mandibular notch in Class I. Mandibular morphology showed change according to facial skeletal type. Correlations were also observed between the cephalometric analysis values and mandibular morphology.

Indications for cone beam computed tomography in children and young patients in a Turkish subpopulation.

BACKGROUND: Cone beam computed tomography (CBCT) imaging is widely used in children; however, it remains controversial because of the health effects of radiation. AIM: This retrospective study investigated the indications for CBCT and dentomaxillofacial pathologies in paediatric patients. MATERIALS AND METHODS: CBCT images of 329 paediatric patients (i.e., aged <18 years) were investigated retrospectively. CBCT images were obtained with five fields of view (FOV). CBCT indications were categorised as surgery and orthodontics. The effects of age, sex, and FOV were evaluated. The level of significance was P = 0.05. RESULTS: The most common orthodontic indications were malocclusion and dentomaxillofacial anomalies (38.5%), followed by the localisation of impacted teeth (33.1%). There was no relationship between sex and indications. There were significant associations between age groups and malocclusion and dentomaxillofacial anomalies, localisation of impacted teeth, and trauma. The face was the most frequently imaged region, followed by the jaws (maxilla and mandible). CONCLUSION: The most common indication for CBCT was malocclusion and dentomaxillofacial anomalies in the primary and permanent dentition age groups, whereas the localisation of impacted teeth was the most common indication in the mixed dentition age group. Generally, CBCT was indicated in orthodontics and surgery.

Prenatally Diagnosed Cases of Binder Phenotype Complicated by Respiratory Distress in the Immediate Postnatal Period.

Binder phenotype, or maxillonasal dysostosis, is a distinctive pattern of facial development characterized by a short nose with a flat nasal bridge, an acute nasolabial angle, a short columella, a convex upper lip, and class III malocclusion. We report 3 cases of prenatally diagnosed Binder phenotype associated with perinatal respiratory impairment.

Fibrous Dysplasia Characterization Using Lacunarity Analysis.

Fibrous dysplasia (FD) is a developmental anomaly in which the normal medullary space of the affected bone is replaced by fibro-osseous tissue. This condition is typically encountered in adolescents and young adults. It affects the maxillofacial region and it can often cause severe deformity and asymmetry. Therefore, accurate diagnosis is critical to determine the appropriate treatment of each case. In this sense, computed tomography (CT) is a relevant resource among the imaging techniques for correct diagnosis of this condition. Thus, in this paper, we propose to analyze fibrous dysplasia through its texture pattern. To accomplish this task, we propose to use lacunarity analysis, a multiscale method for describing patterns of spatial dispersion. Results indicated lower lacunarity values for fibrous dysplasia in comparison to normal bone samples, an indication that their texture images are more homogeneous, and a high separability between the classes when using principal component analysis (PCA) and decision trees for statistical analysis.

Prenatal diagnosis of Binder's syndrome: report of two cases.

OBJECTIVE: Binder syndrome is a rare congenital malformation presenting an abnormal maxilla's development associated to other characteristical facial features, like absence or decreased nasal bridge, short nasal columella, convex upper lip with associated dental Angle Class III malocclusion, atrophy of the nasal mucosa, and absence of the frontal sinus. Mental retardation and other clinical signs may also be present. Two cases of Binder syndrome were diagnosed at 22 weeks of gestation during the second trimester ultrasound (2D). CASES REPORT: The first feature detected, in both cases, was a flattened fetal nose in the mid-sagittal plane. Further controls objectivated absence of the naso-frontal angle and a mild hypertelorism. In both cases the parents were informed of the findings and the impossibility of excluding other associated features diagnosed after birth. Once the differential diagnosis was performed, one of the couples decided to terminate the pregnancy. The findings postmortem confirmed the diagnosis. In the second case, the newborn presented the phenotype previously detected, however, a normal psychomotor development was eventually evidenced. CONCLUSION: The Binder syndrome is an uncommon clinical entity with a recognizable congenital condition characterized by a retruded midface and an extremely flat nose. The exact birth prevalence remains unknown. It is important to understand that Binder's syndrome has a variable prognosis, depending on the other associated features it presents. When diagnosed, an accurate differential diagnosis has to be performed.

Evaluation of the mandibular split patterns in sagittal split ramus osteotomy.

PURPOSE: To evaluate the split patterns of the mandibular ramus in sagittal split ramus osteotomy (SSRO) using cone-beam computed tomography (CBCT) and examine the related anatomic features that may be associated with these split patterns. PATIENTS AND METHODS: The authors designed and implemented a retrospective cohort study and enrolled a sample composed of consecutive patients with different maxillofacial deformities who underwent an SSRO from July 2011 through October 2012 at the Department of Orthognathic Surgery at the Tianjin Stomatological Hospital of Nankai University. The split patterns, which were selected at random at 1 side per patient, were evaluated by CBCT as the outcome variable 1 month after the operation. The predictor variable was composed of a set of heterogeneous anatomic variables that could be associated with the split patterns. Type I split was defined as a split at the lingual side near the mylohyoid sulcus. Type II split was defined as a split at the posterior border of the mandibular ramus. Appropriate bivariate and regression statistics were computed, and the level of statistical significance was set at a P value less than .05. RESULTS: One hundred thirty patients with different maxillofacial deformities (62 male and 68 female; mean age, 23 yr) underwent an SSRO. Two types of split patterns of the mandibular ramus were observed in SSRO: a split at the lingual side near the mylohyoid sulcus, which occurred in 75.38% of patients, and split at the posterior border region of the mandibular ramus, which occurred in 24.62% of patients. No fracture lines were observed through the mandibular canal. The thickness of the lingual cortical bone between the mandibular canal and the posterior border of the ramus was significantly associated with the split patterns (P < .05). The thickness of the cortical bone in the posterior border of the ramus, the degree of the mandibular angle, and the shapes of the mandibular ramus in the axial plane also were found to influence these split patterns. There was no meaningful association between the split patterns and a patient's age and gender. CONCLUSION: The split patterns of the mandibular ramus during SSRO were influenced by some anatomic features of the mandibular ramus. Therefore, examining the anatomy of the mandible with CBCT before surgery may play an important role in predicting the split patterns of the mandibular ramus during SSRO.

Postprocessing in Maxillofacial Multidetector Computed Tomography.

Multidetector computed tomography (CT) and volumetric rendering techniques have always been a useful support for the anatomical and pathological study of the maxillofacial district. Nowadays accessibility to multidetector CT scanners allows the achievement of images with an extremely thin collimation and with high spatial resolution, not only along the axial plane but also along the patient's longitudinal axis. This feature is the main theoretical assumption for multiplanar imaging and for an optimal 3-dimensional postprocessing. Multiplanar reconstruction (MPR) techniques permit images along any plane in the space to be obtained, including curved planes; this feature allows the representation in a single bidimensional image of different anatomical structures that develop on multiple planes. For this reason MPR techniques represent an unavoidable step for the study of traumatic pathology as well as of malformative, neoplastic, and inflammatory pathologies. Among 3-dimensional techniques, Maximum Intensity Projection and Shaded Surface Display are routinely used in clinical practice. In addition, volumetric rendering techniques allow a better efficacy in representing the different tissues of maxillofacial district. Each of these techniques give the radiologist an undoubted support for the diagnosis and the characterization of traumatic and malformative conditions, have a critical utility in the neoplastic evaluation of primary or secondary bone involvement, and are also used in the planning of the most modern radiosurgical treatments. The aim of this article is to define the main technical aspects of imaging postprocessing in maxillofacial CT and to summarize when each technique is indicated, according to the different pathologies of this complex anatomical district.

Malformations of the zygomatic and maxillary regions.

The maxillofacial region develops during 3 to 8 weeks in an embryo. The process involves neural crest cell migration and proliferation as well as facial protrusion jointing and fusion. The maxillofacial region is one of the predilection sites of congenital malformations. We treated a 5-year-old Chinese boy with abnormal development of the left maxillofacial region. We describe in detail the patient's characteristics, diagnosis, and treatment processes and try to explain the possible causes of the disease.

Inexperienced sonographers can successfully visualize and assess a three-dimensional image of the fetal face using a standardized ultrasound protocol.

INTRODUCTION: A standardized three-dimensional ultrasonographic (3DUS) protocol is described that allows fetal face reconstruction. Ability to identify cleft lip with 3DUS using this protocol was assessed by operators with minimal 3DUS experience. MATERIAL AND METHODS: 260 stored volumes of fetal face were analyzed using a standardized protocol by operators with different levels of competence in 3DUS. The outcomes studied were: (1) the performance of post-processing 3D face volumes for the detection of facial clefts; (2) the ability of a resident with minimal 3DUS experience to reconstruct the acquired facial volumes, and (3) the time needed to reconstruct each plane to allow proper diagnosis of a cleft. RESULTS: The three orthogonal planes of the fetal face (axial, sagittal and coronal) were adequately reconstructed with similar performance when acquired by a maternal-fetal medicine specialist or by residents with minimal experience (72 vs. 76%, p = 0.629). The learning curve for manipulation of 3DUS volumes of the fetal face corresponds to 30 cases and is independent of the operator's level of experience. DISCUSSION: The learning curve for the standardized protocol we describe is short, even for inexperienced sonographers. This technique might decrease the length of anatomy ultrasounds and improve the ability to visualize fetal face anomalies.

Impact of cone-beam computed tomography on orthodontic diagnosis and treatment planning.

INTRODUCTION: In this study, we measured the impact of cone-beam computed tomography (CBCT) on orthodontic diagnosis and treatment planning. METHODS: Participant orthodontists shown traditional orthodontic records for 6 patients were asked to provide a diagnostic problem list, a hypothetical treatment plan, and a clinical certainty. They then evaluated a CBCT scan for each patient and noted any changes, confirmations, or enhancements to their diagnosis and treatment plan. RESULTS: The number of diagnosis and treatment plan changes varied widely by patient characteristics. The most frequently reported diagnosis and treatment plan changes occurred in patients with unerupted teeth, severe root resorption, or severe skeletal discrepancies. We found no benefit in terms of changes in treatment plan for patients when the reason for obtaining a CBCT scan was to examine for abnormalities of the temporomandibular joint or airway, or crowding. Orthodontic participants who own CBCT machines or use CBCT scans frequently in practice reported significantly more diagnosis and treatment plan changes and greater confidence after viewing the CBCT scans during the study. CONCLUSIONS: The results of this study support obtaining a CBCT scan before orthodontic diagnosis and treatment planning when a patient has an unerupted tooth with delayed eruption or a questionable location, severe root resorption as diagnosed with a periapical or panoramic radiograph, or a severe skeletal discrepancy. We propose that CBCT scans should be ordered only when there is clear, specific, individual clinical justification.

Cone beam computed tomography--current understanding and evidence for its orthodontic applications?

Cone beam computed tomography (CBCT) is a fast developing technology which provides relatively low-dose, high spatial resolution imaging of the craniofacial complex in three dimensions (3D). During the past decade, the number of CBCT-related publications in the literature has increased significantly, but the crucial question is whether this technology leads to improved outcomes. In this paper, the literature is reviewed and the main applications of CBCT in orthodontics are highlighted, as well as the current evidence and understanding in each area. It is clear that at the present time, despite the popularity of CBCT, there is no clear evidence that the information obtained from these images substantially enhances clinical treatment decisions. Future research on CBCT should focus on interpretation of the images obtained. Visualizing the dentofacial skeleton in ever greater detail may be seductive, but without understanding the implications of findings such as 'minor' external root resorption or having the technical ability to provide treatment at a microscopic level may mean that these images do not have any meaningful impact on clinical practice.

The fetal profile line: a proposal for a sonographic reference line to classify forehead and mandible anomalies in the second and third trimester.

OBJECTIVES: To test the fetal profile (FP) line, defined as the line that passes through the anterior border of the mandible and the nasion, as a reference line for forehead and mandible anomalies. METHODS: Volumes of 248 normal and 24 pathological fetuses (16-36 and 19-37 weeks' gestation, respectively) were analysed retrospectively. When the FP line passes anteriorly, across or posteriorly to the frontal bone, this was defined as 'negative', 'zero' or 'positive', respectively. When the FP line was positive the distance (F distance) between the FP line and the frontal bone was measured. RESULTS: No cases with a negative FP line were found in the normal fetuses. Before 27 weeks' gestation the FP line was always 'zero' except in one case. After 27 weeks' gestation the FP line was 'positive' in up to 25% (F distance (mean, range): 2.8, 2.1-3.6 mm). The FP line correctly identified 13 cases with retrognathia, 5 cases with frontal bossing and 3 cases with a sloping forehead. CONCLUSION: Although large prospective studies are needed, the FP line may be a useful tool to detect second trimester profile anomalies such as retrognathia, sloping forehead and frontal bossing with the possibility of quantifying the latter.

Dental outcomes in computer-assisted orthognathic surgery.

The purpose of this study was to assess the effectiveness of computer-aided orthognathic surgery in reducing incisal overjet and establishing class I occlusion in subjects with dentofacial deformities. To address the research purpose, the investigators initiated a retrospective cohort study and enrolled a sample of subjects who underwent computer-assisted orthognathic surgery for dentofacial deformities. Two examiners assessed preoperative and postoperative lateral cephalometric radiographs for change in overjet after computer-assisted orthognathic surgery. Preoperative and postoperative occlusal photographs were then reviewed to assess for establishment of class I occlusion after computer-assisted orthognathic surgery. Cohen κ coefficient was used to assess for interrater agreement. A matched-pairs t-test was used to assess reduction in incisal overjet after computer-assisted orthognathic surgery. The sample was composed of 9 subjects who underwent computer-assisted surgery for dentofacial deformities. There was good interrater consistency for preoperative measurement of overjet (κ = 0.7, P ≤ 0.001). There was fair interrater consistency for postoperative measurement of overjet (κ = 0.4, P = 0 .02). Both examiners agreed on preoperative and postoperative assessments of occlusal photographs. There was a 3.4-mm reduction in incisal overjet after computer-assisted orthognathic surgery (P ≤ 0.001). Mean postoperative absolute overjet was 1.3 mm. In subjects with dentofacial deformities, computer-aided orthognathic surgery was effective in reducing incisal overjet and establishing class I occlusion.

Aplasia and agenesis of the frontal sinus in Turkish individuals: a retrospective study using dental volumetric tomography.

Agenesis of the paranasal sinuses is an uncommon clinical condition that appears mainly in the frontal (12%) and maxillary (5-6%) sinuses; in some populations, it appears at a higher proportion. This study investigated the prevalence of agenesis of the frontal sinuses using dental volumetric tomography (DVT) in Turkish individuals. The frontal sinuses of 410 patients were examined by DVT scans in the coronal planes for evidence of the absence of the frontal sinuses. A bilateral and unilateral absence of the frontal sinuses was seen in 0.73% and 1.22% of cases, respectively. In one case, both agenesis and aplasia of the frontal sinus was seen (0.24%). The low percentage of frontal sinus agenesis must be considered during pre-surgical planning related to the sinuses. DVT may be used as a diagnostic tool for the examination of frontal sinus aplasia.

A new method to orient 3-dimensional computed tomography models to the natural head position: a clinical feasibility study.

PURPOSE: The purpose of this study was to evaluate the clinical feasibility of a new method to orient 3-dimensional (3D) computed tomography models to the natural head position (NHP). This method uses a small and inexpensive digital orientation device to record NHP in 3 dimensions. This device consists of a digital orientation sensor attached to the patient via a facebow and an individualized bite jig. The study was designed to answer 2 questions: 1) whether the weight of the new device can negatively influence the NHP and 2) whether the new method is as accurate as the gold standard. PATIENTS AND METHODS: Fifteen patients with craniomaxillofacial deformities were included in the study. Each patient's NHP is recorded 3 times. The first NHP was recorded with a laser scanning method without the presence of the digital orientation device. The second NHP was recorded with the digital orientation device. Simultaneously, the third NHP was also recorded with the laser scanning method. Each recorded NHP measurement was then transferred to the patient's 3D computed tomography facial model, resulting in 3 different orientations for each patient: the orientation generated via the laser scanning method without the presence of the digital orientation sensor and facebow (orientation 1), the orientation generated by use of the laser scanning method with the presence of the digital orientation sensor and facebow (orientation 2), and the orientation generated with the digital orientation device (orientation 3). Comparisons are then made between orientations 1 and 2 and between orientations 2 and 3, respectively. Statistical analyses are performed. RESULTS: The results show that in each pair, the difference (Δ) between the 2 measurements is not statistically significantly different from 0°. In addition, in the first pair, the Bland-Altman lower and upper limits of the Δ between the 2 measurements are within 1.5° in pitch and within a subdegree in roll and yaw. In the second pair, the limits of the Δ in all 3 dimensions are within 0.5°. CONCLUSION: Our technique can accurately record NHP in 3 dimensions and precisely transfer it to a 3D model. In addition, the extra weight of the digital orientation sensor and facebow has minimal influence on the self-balanced NHP establishment.

Using a clinical protocol for orthognathic surgery and assessing a 3-dimensional virtual approach: current therapy.

Oral and maxillofacial surgeons who perform orthognathic surgery face major changes in their practices, and these challenges will increase in the near future, because the extraordinary advances in technology applied to our profession are not only amazing but are becoming the standard of care as they promote improved outcomes for our patients. Orthognathic surgery is one of the favorite areas of practicing within the scope of practice of an oral and maxillofacial surgeon. Our own practice in orthognathic surgery has completed over 1,000 surgeries of this type. Success is directly related to the consistency and capability of the surgical-orthodontic team to achieve predictable, stable results, and our hypothesis is that a successful result is directly related to the way we take our records and perform diagnosis and treatment planning following basic general principles. Now that we have the opportunity to plan and treat 3-dimensional (3D) problems with 3D technology, we should enter into this new era with appropriate standards to ensure better results, instead of simply enjoying these new tools, which will clearly show not only us but everyone what we do when we perform orthognathic surgery. Appropriate principles need to be taken into account when implementing this new technology. In other words, new technology is welcome, but we do not have to reinvent the wheel. The purpose of this article is to review the current protocol that we use for orthognathic surgery and compare it with published protocols that incorporate new 3D and virtual technology. This report also describes our approach to this new technology.