Accuracy and reliability of automated three-dimensional facial landmarking in medical and biological studies. A systematic review.

BACKGROUND: 3D facial landmarking is becoming a fundamental part of clinical and biological applications. Manual landmarking is time consuming and prone to cumulative errors, so attempts have been made to automate 3D facial landmarking. However, data in the literature are sparse. OBJECTIVES: The objectives of this study are to investigate current evidence for the accuracy and reliability of various 3D facial automated landmarking methods used in medical and biological studies and evaluate their performance against the manual annotation method. SEARCH METHODS: Electronic and manual searches of the literature were performed in April 2021. SELECTION CRITERIA: Only studies that were published in English and evaluated the accuracy of automated landmarking algorithms in 3D facial images for medical or biological settings were included. DATA COLLECTION AND ANALYSIS: Two authors independently screened the articles for eligibility. The QUADAS-2 tool was used for the quality analysis of the included studies. Due to the heterogeneity of the selected studies, a meta-analysis was not possible, so a narrative synthesis of the findings was performed. RESULTS: From 1002 identified records, after applying the inclusion and exclusion criteria, 14 articles were ultimately selected, read, and critically analysed. Different algorithms were used for the automated 3D landmarking of various numbers of facial landmarks ranging from 10 to 29 landmarks. The average difference between the manual and automated methods ranged from 0.67 to 4.73 mm, and the best performance was achieved using deep learning models. Poor study design and inadequate reporting were found in the implementation of the reference standards and population selection for the intended studies, which could have led to overfitting of the tested algorithm. LIMITATIONS: This systematic review was limited by the quality of the included studies and uncovered several methodological limitations evident in the corresponding literature. CONCLUSION AND IMPLICATIONS: Compared to manual landmarking, automated Landmark localization of individual facial landmarks reported in the literature is not accurate enough to allow their use for clinical purposes. This result indicates that automatic facial landmarking is still developing, and further studies are required to develop a system that could match or exceed the performance of the current gold standard. REGISTRATION: PROSPERO: CRD42021241531.

Influence of students' self-directed learning on situational interest: A prospective randomised study.

INTRODUCTION: Evaluate the effectiveness of a newly developed interactive 3D head and neck software package on students' situational interest and knowledge acquisition. MATERIAL AND METHODS: A prospective randomised controlled study was carried out on two groups of dental students, 25 each. The study group "A" received education on head and neck anatomy using an interactive 3D software package. The same content was delivered to the students in group B via the standard PowerPoint presentation. The same lecturer delivered the educational modules over 80 min. Throughout the course of learning, the students completed a situational interest questionnaire, every 20 min. At the end of the session, each participant completed a knowledge acquisition test. RESULTS: Wilcoxon signed-rank sum test showed a clear difference in the pattern of situational interest between the two groups; a statistically significant drop in the interest in the head and neck was noted amongst the students after 40 min in group B (p < .05). An opposite pattern was detected amongst the students in group A. No statistically significant differences were detected in the knowledge acquisition between the two groups. CONCLUSION: The 3D software package of the head and neck anatomy has augmented the students' situational interest and improved their knowledge acquisition. However, further research is required to evaluate students' perception and experience of its use before it is widely generalised in universities and educational institutes.

Ludwig's angina in Nigeria: The disease of the poor and health inequality!

AIM: highlight the health inequality and identify opportunities to improve the care delivered to the patients who suffer from Ludwig's angina which could have national and international clinical impact. MATERIALS AND METHODS: Data was collected from three major oral and maxillofacial centers, in Nigeria including Benin, Lagos and Kano. A protocol was developed for data collection which included demographic details, socio-economic status, management of the air way, the associated morbidities and mortalities. RESULTS: Forty-nine were managed in Benin, 57 in Lagos and 66 in Kano. Diabetes was the most prevalent underlying systematic condition, affecting 21% of the Ludwig's angina patients in Lagos. Poverty was a common denominator, 90% of the patients from Kano were unemployed compared to 23% and 8% from Lagos and Benin respectively. For most of the patients, the airway was monitored. Incision and drainage were carried out in most of the cases at Benin and Lagos, but it was only considered in 50% of the cases in Kano. Mortality ranged from 4% in Benin to 12% in Lagos and it was as high as 19% in Kano. CONCLUSION: poor access to oral healthcare, unemployment and low socio-economic status are important predisposing factors of Ludwig's angina.

A novel surgical model for the preclinical assessment of the osseointegration of dental implants: a surgical protocol and pilot study results.

BACKGROUND: Dental implants are considered the gold standard replacement for missing natural teeth. The successful clinical performance of dental implants is due to their ability to osseointegrate with the surrounding bone. Most dental implants are manufactured from Titanium and it alloys. Titanium does however have some shortcomings so alternative materials are frequently being investigated. Effective preclinical studies are essential to transfer the innovations from the benchtop to the patients. Many preclinical studies are carried out in the extra-oral bones of small animal models to assess the osseointegration of the newly developed materials. This does not simulate the oral environment where the dental implants are subjected to several factors that influence osseointegration; therefore, they can have limited clinical value. AIM: This study aimed to develop an appropriate in-vivo model for dental implant research that mimic the clinical setting. The study evaluated the applicability of the new model and investigated the impact of the surgical procedure on animal welfare. MATERIALS AND METHODS: The model was developed in male New Zealand white rabbits. The implants were inserted in the extraction sockets of the secondary incisors in the maxilla. The model allows a split-mouth comparative analysis. The implants' osseointegration was assessed clinically, radiographically using micro-computed tomography (µ-CT), and histologically. A randomised, controlled split-mouth design was conducted in 6 rabbits. A total of twelve implants were inserted. In each rabbit, two implants; one experimental implant on one side, and one control implant on the other side were applied. Screw-shaped implants were used with a length of 8 mm and a diameter of 2 mm. RESULTS: All the rabbits tolerated the surgical procedure well. The osseointegration was confirmed clinically, histologically and radiographically. Quantitative assessment of bone volume and mineral density was measured in the peri-implant bone tissues. The findings suggest that the new preclinical model is excellent, facilitating a comprehensive evaluation of osseointegration of dental implants in translational research pertaining to the human application. CONCLUSION: The presented model proved to be safe, reproducible and required basic surgical skills to perform.

The Validation of an Innovative Method for 3D Capture and Analysis of the Nasolabial Region in Cleft Cases.

OBJECTIVE: To validate a newly developed method for capturing 3-dimensional (3D) images of the nasolabial region for assessing upper lip scarring and asymmetry in surgically managed unilateral cleft lip and palate (UCLP) cases. DESIGN: Validation study, single cohort. MATERIALS AND METHODS: Eighteen surgically managed UCLP cases were recruited, the nasolabial region of each face was scanned using an intraoral scanner (IOS) to produce 3D images. The images were manually segmented to allow the calculation of surface area of the scar and upper lip asymmetry. Five professionals and 5 lay assessors subjectively evaluated the same images and graded the upper lip scarring and asymmetry at 2 separate occasions. The relationship between the subjective and objective assessments was evaluated. RESULTS: Moderate correlation was found between subjective and objective evaluations of the upper lip scarring and total asymmetry. The captured 3D images were of good quality for the objective measurements of lip asymmetry and residual scarring. Moderate to strong correlations were detected between the 2 panels (T ranging between 0.5 and 0.9) with no significant difference (P > .05) in the mean score of the subjectively evaluated parameters. CONCLUSION: The IOS is a useful tool for the capture of the nasolabial morphology. The captured 3D images are a reliable source for measuring lip asymmetry and scar surface area. The method has sufficient validity for routine clinical use and for objective outcome measures of the surgical repair of cleft lip.

An Innovative Assessment of the Dynamics of Facial Movements in Surgically Managed Unilateral Cleft Lip and Palate Using 4D Imaging.

OBJECTIVE: Assess facial asymmetry during maximum smile in patients with surgically managed unilateral cleft lip and palate (UCLP), using a dynamic 3-dimensional (3D) imaging (4-dimensional) system. DESIGN: Prospective 2 cohort comparative study. METHODS: Twenty-five surgically managed UCLP cases and 75 controls at 8 to 10 years of age were recruited. Facial movements during maximum smile were recorded using video stereophotogrammetry at a rate of 60 3D facial images per second. Maximum smile took approximately 3 seconds and generated 180 3D facial images for the analysis. A generic facial mesh which consists of more than 7000 quasi landmarks was used for the assessment of facial asymmetry at 5 key 3D frames representing the pattern of maximum smile. RESULTS: Statistically significant differences were seen regarding the magnitude of facial asymmetry between the UCLP group and the noncleft controls. Higher average asymmetry in the UCLP group was seen in the 3D frame midway between maximum smile and rest (frame 4) followed by the frame at peak expression of maximum smile (frame 3). The average magnitude of nasolabial asymmetry of the control group was within 0.5 mm in comparison with the UCLP cases which was about 1.8 mm. CONCLUSION: This study provided for the first time, an objective tool for analysis of the dynamics of muscle movements which provided an unprecedented insight into the anatomical basis of the residual dysmorphology. The research demonstrates the limitations of the primary lip repair in achieving symmetrical results and underpins the required refinements to improve the quality of surgical repair of cleft lip.

The Clinical Application of Recombinant Human Bone Morphogenetic Protein 7 for Reconstruction of Alveolar Cleft: 10 Years' Follow-Up.

PURPOSE: The purpose of this study was to report on a 10-year assessment after the application of recombinant human bone morphogenetic protein 7 (rhBMP-7) for the reconstruction of alveolar clefts. PATIENTS AND METHODS: This study was conducted as a prospective phase II clinical trial on 9 unilateral and 2 bilateral alveolar clefts that received rhBMP-7 (Osigraft; Stryker Biotech, UK). The mean age of the patients at surgery was 10.4 years. At 6 months postoperatively, occlusal radiographs were taken to evaluate bone formation at the cleft site. Patients were followed within the routine cleft care pathway for 10 years to monitor the impact of bone morphogenetic protein 7 on orthodontic treatments and maxillary growth. Radiographs were taken according to the standard cleft care protocol. RESULTS: The radiographic assessment of the unilateral cleft lip and palate cases suggested good bone formation with a Kindelan score of grade 1 or 2. The bilateral alveolar cleft cases had a score of grade 3 or 4, indicating failure or partial failure. The children with successful grafts underwent a routine orthodontic follow-up without incident. The maxillary growth appeared to be similar to that in cases grafted with autogenous bone. No long-term complications and no abnormal pattern of bone formation were detected. CONCLUSIONS: The study provides unique evidence on the long-term safety of rhBMP-7 when applied at the area of skeletal immaturity for the reconstruction of alveolar clefts in children.

Psychology input to an orthognathic clinic: Patients' perception of service quality.

AIMS: The aim of this study was to assess patient satisfaction with a clinical psychology service, integrated within an inter-disciplinary orthognathic planning clinic. METHOD: A self-report, custom-designed questionnaire was sent to patients who had completed orthognathic treatment within the last three years. Of the 60 patients approached, 49 responded. RESULTS: The great majority of patients agreed that there was a need for a psychological assessment and that its purpose was adequately explained. Most patients were happy with the information given during their appointment and found the experience helpful. A number of patients felt that additional appointments would have been helpful shortly before, and after, surgery. CONCLUSIONS: The group of orthognathic patients studied found the pre-treatment psychology assessment, provided for them through the combined clinic, to be very acceptable and beneficial. Some suggested that further appointments, throughout the treatment journey, as well as supportive literature, might also have been helpful.

Longitudinal 3D Assessment of Facial Asymmetry in Unilateral Cleft Lip and Palate.

OBJECTIVE: Longitudinal evaluation of asymmetry of the surgically managed unilateral cleft lip and palate (UCLP) to assess the impact of facial growth on facial appearance. DESIGN: Prospective study. SETTING: Glasgow Dental Hospital and School, University of Glasgow, United Kingdom. PATIENTS: Fifteen UCLP infants. METHOD: The 3-D facial images were captured before surgery, 4 months after surgery, and at 4-year follow-up using stereophotogrammetry. A generic mesh which is a mathematical facial mask that consists of thousands of points (vertices) was conformed on the generated 3-D images. Using Procustean analysis, an average facial mesh was obtained for each age-group. A mirror image of each average mesh was mathematically obtained for the analysis of facial dysmorphology. Facial asymmetry was assessed by measuring the distances between the corresponding vertices of the original and the mirror copy of the conformed meshes, and this was displayed in color-coded map. RESULTS: There was a clear improvement in the facial asymmetry following the primary repair of cleft lip. Residual asymmetry was detected around the nasolabial region. The nasolabial region was the most asymmetrical region of the face; the philtrum, columella, and the vermillion border of the upper lip showed the maximum asymmetry which was more than 5 mm. Facial growth accentuated the underlying facial asymmetry in 3 directions; the philtrum of the upper lip was deviated toward the scar tissue on the cleft side. The asymmetry of the nose was significantly worse at 4-year follow-up ( P < .05). CONCLUSION: The residual asymmetry following the surgical repair of UCLP was more pronounced at 4 years following surgery. The conformed facial mesh provided a reliable and innovative tool for the comprehensive analysis of facial morphology in UCLP. The study highlights the need of refining the primary repair of the cleft and the potential necessity for further corrective surgery.

The application of virtual reality and augmented reality in Oral & Maxillofacial Surgery.

BACKGROUND: Virtual reality is the science of creating a virtual environment for the assessment of various anatomical regions of the body for the diagnosis, planning and surgical training. Augmented reality is the superimposition of a 3D real environment specific to individual patient onto the surgical filed using semi-transparent glasses to augment the virtual scene.. The aim of this study is to provide an over view of the literature on the application of virtual and augmented reality in oral & maxillofacial surgery. METHODS: We reviewed the literature and the existing database using Ovid MEDLINE search, Cochran Library and PubMed. All the studies in the English literature in the last 10 years, from 2009 to 2019 were included. RESULTS: We identified 101 articles related the broad application of virtual reality in oral & maxillofacial surgery. These included the following: Eight systematic reviews, 4 expert reviews, 9 case reports, 5 retrospective surveys, 2 historical perspectives, 13 manuscripts on virtual education and training, 5 on haptic technology, 4 on augmented reality, 10 on image fusion, 41 articles on the prediction planning for orthognathic surgery and maxillofacial reconstruction. Dental implantology and orthognathic surgery are the most frequent applications of virtual reality and augmented reality. Virtual planning improved the accuracy of inserting dental implants using either a statistic guidance or dynamic navigation. In orthognathic surgery, prediction planning and intraoperative navigation are the main applications of virtual reality. Virtual reality has been utilised to improve the delivery of education and the quality of training in oral & maxillofacial surgery by creating a virtual environment of the surgical procedure. Haptic feedback provided an additional immersive reality to improve manual dexterity and improve clinical training. CONCLUSION: Virtual and augmented reality have contributed to the planning of maxillofacial procedures and surgery training. Few articles highlighted the importance of this technology in improving the quality of patients' care. There are limited prospective randomized studies comparing the impact of virtual reality with the standard methods in delivering oral surgery education.

Effectiveness of Immersive Virtual Reality in Surgical Training-A Randomized Control Trial.

PURPOSE: Surgical training methods are evolving with the technological advancements, including the application of virtual reality (VR) and augmented reality. However, 28 to 40% of novice residents are not confident in performing a major surgical procedure. VR surgery, an immersive VR (iVR) experience, was developed using Oculus Rift and Leap Motion devices (Leap Motion, Inc, San Francisco, CA) to address this challenge. Our iVR is a multisensory, holistic surgical training application that demonstrates a maxillofacial surgical technique, the Le Fort I osteotomy. The main objective of the present study was to evaluate the effect of using VR surgery on the self-confidence and knowledge of surgical residents. MATERIALS AND METHODS: A multisite, single-blind, parallel, randomized controlled trial (RCT) was performed. The participants were novice surgical residents with limited experience in performing the Le Fort I osteotomy. The primary outcome measures were the self-assessment scores of trainee confidence using a Likert scale and an objective assessment of the cognitive skills. Ninety-five residents from 7 dental schools were included in the RCT. The participants were randomly divided into a study group of 51 residents and a control group of 44. Participants in the study group used the VR surgery application on an Oculus Rift with Leap Motion device. The control group participants used similar content in a standard PowerPoint presentation on a laptop. Repeated measures multivariate analysis of variance was applied to the data to assess the overall effect of the intervention on the confidence of the residents. RESULTS: The study group participants showed significantly greater perceived self-confidence levels compared with those in the control group (P = .034; α = 0.05). Novices in the first year of their training showed the greatest improvement in their confidence compared with those in their second and third year. CONCLUSIONS: iVR experiences improve the knowledge and self-confidence of the surgical residents.

Replacement of the Distorted Dentition of the Cone-Beam Computed Tomography Scans for Orthognathic Surgery Planning.

PURPOSE: Cone-beam computed tomography (CBCT) does not record dental morphology accurately because of the scattering produced by metallic restorations and the reported magnification of the dentition. The aim of this study was the development and evaluation of a new method for the replacement of the distorted dentition of CBCT scans with a 3-dimensional (3D) dental image captured by a digital intraoral camera. MATERIALS AND METHODS: Six dried skulls with orthodontic brackets fixed on the teeth were used in this study. Three intraoral markers made of dental stone were constructed and attached to orthodontic brackets. The skulls were scanned by CBCT and the occlusal surfaces were captured using the TRIOS 3D intraoral scanner. The digital intraoral scan (IOS) was fused into the CBCT models. This produced a new composite digital model of the skull and the dentition. The skulls were scanned again using the commercially accurate Faro laser arm to produce the 3D model the skull and teeth gold standard for the assessment of the accuracy of the developed method. This was assessed by measuring the distance between the occlusal surfaces of the new composite model and the gold standard 3D laser produced model. RESULTS: The results showed the errors related to the superimposition of the intraoral image on the CBCT to replace the distorted dentition were 0.11 to 0.20 mm. CONCLUSION: The results of this novel method suggest that the dentition on the CBCT scan can be accurately replaced with the digital IOS image captured by an intraoral scanner to create a composite model that will improve the accuracy of digital orthognathic surgical planning and the fabrication of the guiding occlusal wafer.

Does rapid maxillary expansion affect nasopharyngeal airway? A prospective Cone Beam Computerised Tomography (CBCT) based study.

BACKGROUND AND PURPOSE: There is limited literature discussing the three dimnesional (3D) impact of rapid maxillary expansion (RME) on upper airway. The purpose of this prospective Cone Beam Computerised Tomography (CBCT) based study is to assess the immediate 3D effects and to correlate the volumteric changes in the upper naspharyngeal airway spaces secondary to RME. MATERIALS AND METHODS: Seventeen participants (8 male, 9 female, with a mean age of 12.6 ± 1.8 years), who required RME for the management of narrow maxillary arch, were recruited for this study. The prescribed expansion regimen was quarter turn (0.25 mm), twice a day until over-expansion was achieved. The mean period for the active phase was 14 days with a range of 12-21 days. Pretreatment (T1) and immediate post-expansion (T2) CBCT images were obtained and then processed using ITK snap and OnDemand3D softwar packages. Paired t-test and Interclass Correlation Coefficient (ICC) were used to assess the reproducibility of the measurements, student t-test (P < 0.05) and Pearson Correlation Coefficient (PCC) were applied to evaluate the volumetric changes in the nasopharyngeal airway spaces, linear dentolaveolar changes and correlate these changes. MAIN FINDINGS: Though, the data of one patient was excluded from the study, owing to major differences (>5 degrees) in the head and neck posture between T1 and T2 CBCT scans, the study' findings shows that bonded RME is an effective dentoalveolar expander in growing patients (P= 0.01) with an average expansion of 3.7 mm and 2.8 mm in males and females respectively. Likewise, the upper nasopharynx (UNP) expanded significantly (15.2% in males and 12% in females). In comparison, the upper retropalatal space (URP) was significantly reduced, by almost one sixth of its original volume, more in males than females, 11.2% and 2.8% respectively. A strong direct correlation between the maxillary sinus volumetric changes, and between appliance expansion and dentoalveolar expansion were evident (PCC = 0.86, 0.75, respectively). There was also a moderate correlation between changes in the UNP and URP spaces. CONCLUSIONS: RME was found to be an effective dentoalveolar expander and significantly augment the UNP and minimize the URP space. A similar comparative clinical study with long-term follow-up would be beneficial in accurately deteremining the clinical impact of RME on the airway and breathing as well as the stability of these effects.

The definitions of three-dimensional landmarks on the human face: an interdisciplinary view.

The analysis of shape is a key part of anatomical research and in the large majority of cases landmarks provide a standard starting point. However, while the technology of image capture has developed rapidly and in particular three-dimensional imaging is widely available, the definitions of anatomical landmarks remain rooted in their two-dimensional origins. In the important case of the human face, standard definitions often require careful orientation of the subject. This paper considers the definitions of facial landmarks from an interdisciplinary perspective, including biological and clinical motivations, issues associated with imaging and subsequent analysis, and the mathematical definition of surface shape using differential geometry. This last perspective provides a route to definitions of landmarks based on surface curvature, often making use of ridge and valley curves, which is genuinely three-dimensional and is independent of orientation. Specific definitions based on curvature are proposed. These are evaluated, along with traditional definitions, in a study that uses a hierarchical (random effects) model to estimate the error variation that is present at several different levels within the image capture process. The estimates of variation at these different levels are of interest in their own right but, in addition, evidence is provided that variation is reduced at the observer level when the new landmark definitions are used.

Effects of Le Fort I Osteotomy on the Nasopharyngeal Airway-6-Month Follow-Up.

PURPOSE: The literature discussing the impact of a single Le Fort I osteotomy on nasopharyngeal airways is limited. This study assessed the volumetric changes in the nasopharyngeal airway after a single Le Fort I osteotomy and explored the correlation between these changes and 3-dimensional surgical movements of the upper jaw. MATERIALS AND METHODS: This retrospective study was conducted in 40 patients who had undergone a single Le Fort I (maxillary advancement with or without impaction) to correct Class III malocclusion with maxillary hypoplasia. Preoperative (T1) and 6-month postoperative (T2) cone-beam computed tomographic (CBCT) scans of these patients were used for analysis. Maxillary surgical movements and volumetric changes in the nasopharyngeal airway were measured. The reproducibility of the measurements was evaluated using paired t tests and intraclass correlation coefficients. The Wilcoxon test and Pearson correlation coefficient were applied to evaluate the volumetric changes in the nasopharyngeal airway space and assess the correlations of these changes to the maxillary surgical movements. RESULTS: Six patients were excluded from the study owing to major differences (>5°) in their head and neck posture between the T1 and T2 CBCT scans. The errors of the repeated measurements were insignificant (P > .05), with a high level of agreement (r = 0.99; P < .05) between the repeated digitization of the landmarks. There was a statistically significant impact of a Le Fort I osteotomy on the right maxillary sinus (decreased by 17.8%) and the lower retropalatal space (expanded by 17.3%; P < .05). The correlation between the change in airway volume and the magnitude of surgical maxillary movements was moderate (r = .4). Similarly, there was a moderate correlation between changes in the upper nasopharynx and those in the hypopharynx. CONCLUSION: The single Le Fort I osteotomy was found to increase the retroglossal airway volume. This could be important for the treatment of obstructive sleep apnea in patients with maxillary deficiency. A long-term follow-up assessment of a larger sample with a functional assessment of airway would be beneficial to confirm these findings.

Evaluation of the Reproducibility of Nonverbal Facial Expressions Using a 3D Motion Capture System.

OBJECTIVE: To evaluate the reproducibility of three nonverbal facial expressions using a three-dimensional motion capture system. DESIGN: Prospective, cross-sectional, controlled study. SETTING: Glasgow Dental Hospital and School, University of Glasgow, United Kingdom. PATIENTS AND PARTICIPANTS: Thirty-two subjects, 16 males and 16 females. METHODS: With a three-dimensional video passive stereophotogrammetry imaging system, maximal smile, cheek puff, and lip purse were captured for each subject. Anatomical facial landmarks were digitized on the first frame and then tracked automatically. The same facial expressions were captured 15 minutes later. MAIN OUTCOME MEASURES: The magnitude of each expression and speed of landmark displacement were calculated. The landmark motion curves were spatially and temporally aligned to calculate the similarity of the dynamic movements of the same landmarks between the captures. RESULTS: There were no significant differences between individuals for magnitude (P = .892) or for speed (P = .456). There were significant differences in landmark movement similarity (P = .011); similarity was more reproducible for maximal smile. There was no significant gender effect on the difference in magnitude. There was a significant gender effect on speed to reach maximal smile (P = .044) and a pursed-lip expression (P = .038). There was a significant gender effect on landmark movement similarities (P = .031) for cheek puff expression. CONCLUSIONS: There were no differences in magnitude and speed for maximal smile, cheek puff, and lip purse between the two captures for all participants. For individual expressions, maximal smile expression had the highest similarity value for individual landmarks.

The Impact of Orthognathic Surgery on Facial Expressions.

PURPOSE: The aim of this study was to evaluate the impact of orthognathic surgical correction of facial asymmetry and maxillary hypoplasia on the magnitude and pattern of facial expressions. PATIENTS AND METHODS: This study was carried out on 2 cohorts of patients: in group 1, 10 patients had surgical correction of facial asymmetry; in group 2, 13 patients had Le Fort I osteotomy to correct maxillary hypoplasia. The patients were asked to perform 3 facial expressions (maximal smile, lip purse, and cheek puff) that were recorded using the Di4D image-capture system before and after surgery. The capture of each expression generated 180 3-dimensional (3D) facial images. Twenty-seven facial soft tissue landmarks were digitized on the first frame of the 3D image of each expression and a mathematical generic mesh was applied on the 3D model to clone each patient's face. The cloned mesh was superimposed automatically on each sequence of the 3D images to evaluate the pattern of facial expressions. The digitization of facial landmarks was satisfactorily accurate and reproducible. RESULTS: In group 1, the asymmetry of facial expressions was significantly decreased after surgical correction (P = .0458). In group 2, Le Fort I osteotomy decreased the magnitude of facial expressions (P = .0267). CONCLUSION: This study confirmed that orthognathic surgery affects the dynamics of facial expressions; this should be considered when planning the surgery and informing patients about the surgical correction of dentofacial deformities.

Innovation in prediction planning for anterior open bite correction.

This study applies recent advances in 3D virtual imaging for application in the prediction planning of dentofacial deformities. Stereo-photogrammetry has been used to create virtual and physical models, which are creatively combined in planning the surgical correction of anterior open bite. The application of these novel methods is demonstrated through the surgical correction of a case.

Three-dimensional assessment of facial appearance following surgical repair of unilateral cleft lip and palate.

BACKGROUND AND OBJECTIVE: Objective assessment of postsurgical facial asymmetry can be difficult, but three-dimensional (3D) imaging techniques have made this possible. The objective of this study was to assess residual asymmetry in surgically repaired unilateral cleft lip (UCL) and unilateral cleft lip and palate (UCLP) patients and to compare this with noncleft controls. DESIGN: Retrospective multicohort comparative study. PATIENTS AND METHODS: Fifty-one 10-year-old children with surgically managed UCLP and 44 children with UCL were compared with a control group of 68 ten-year-olds. The 3D facial models at rest and with maximum smile were created using a 3D imaging system. Asymmetry scores were produced using both anatomical landmarks and a novel method of facial curve analysis. RESULTS: Asymmetry for the whole face was significantly higher in both cleft groups compared with controls (P < .001). UCLP asymmetry was higher than UCL (P < .001). In cleft patients, the upper lip and nasal rim were the most asymmetric (P < .001 to .05). Control subjects also displayed a degree of facial asymmetry. Maximum smile did not significantly affect the symmetry of the whole face, but it increased asymmetry of the vermillion border and nasal rim in all three groups (P < .001). CONCLUSIONS: Despite surgical intervention at an early age, asymmetry remains significant in cleft patients at 10 years of age. Three-dimensional imaging is a noninvasive objective assessment tool that identifies specific areas of the face responsible for asymmetry. Facial curve analysis describes the face more comprehensively and characterizes soft tissue contours.

The Clinical Evaluation of the Dynamically Navigated Flapless Placement of Zygomatic Implants: A Randomized Controlled Trial.

PURPOSE: To assess the pain, swelling, infection, and alteration in sensation following the flapless placement of zygomatic implants guided by dynamic navigation. MATERIALS AND METHODS: A randomized controlled trial was conducted on 20 patients. In group 1, the placement of the zygomatic implants was carried out without reflecting a mucoperiosteal flap (flapless). In group 2, a mucoperiosteal flap was raised (flapped). Two zygomatic implants were placed in each patient (one on each side) under local anesthesia, guided by dynamic navigation. Postoperative evaluations included pain (using the visual analogue scale [VAS]), swelling (using standard measurements), maxillary sinus infection, and alteration of sensation (using mechanical stimuli, thermal threshold detection, and a two-point discrimination test). The assessments were carried out at 2 days, 1 week, and then 1, 2, and 3 months postoperatively. RESULTS: In group 1, all implants except for one were successfully osseointegrated. Immediate postoperative pain and swelling were both significantly greater in group 2 (P < .01). No alteration in sensation was detected in any case in the two groups. There were a total of three cases of chronic sinusitis: one in group 1 and two in group 2. CONCLUSIONS: The flapless placement of zygomatic implants guided by dynamic navigation and under local anesthesia improves postoperative recovery.