The precision of drill calibration for dynamic navigation.

OBJECTIVES: To quantify the reproducibility of the drill calibration process in dynamic navigation guided placement of dental implants and to identify the human factors that could affect the precision of this process in order to improve the overall implant placement accuracy. METHODS: A set of six drills and four implants were calibrated by three operators following the standard calibration process of NaviDent® (ClaroNav Inc.). The reproducibility of the position of each tip of a drill or implant was calculated in relation to the pre-planned implants' entry and apex positions. Intra- and inter-operator reliabilities were reported. The effects of the drill length and shape on the reproducibility of the calibration process were also investigated. The outcome measures for reproducibility were expressed in terms of variability range, average and maximum deviations from the mean distance. RESULTS: A satisfactory inter-rater reproducibility was noted. The precision of the calibration of the tip position in terms of variability range was between 0.3 and 3.7 mm. We noted a tendency towards a higher precision of the calibration process with longer drills. More calibration errors were observed when calibrating long zygomatic implants with non-locking adapters than with pointed drills. Flexible long-pointed drills had low calibration precision that was comparable to the non-flexible short-pointed drills. CONCLUSION: The clinicians should be aware of the calibration error associated with the dynamic navigation placement of dental and zygomatic implants. This should be taken in consideration especially for long implants, short drills, and long drills that have some degree of flexibility. CLINICAL SIGNIFICANCE: Dynamic navigation procedures are associated with an inherent drill calibration error. The manual stability during the calibration process is crucial in minimising this error. In addition, the clinician must never ignore the prescribed accuracy checking procedures after each calibration process.

The Accuracy of Intraoral Registration for Dynamic Surgical Navigation in the Edentulous Maxilla.

PURPOSE: Despite the high clinical accuracy of dynamic navigation, inherent sources of error exist. The purpose of this study was to improve the accuracy of dynamic-navigated surgical procedures in the edentulous maxilla by identifying the optimal configuration of intraoral points that results in the lowest possible registration error for direct clinical implementation. MATERIALS AND METHODS: Six different four-area configurations (left and right sides; n = 12) were tested by three operators against two negative controls (left and right sides) and one positive control (three-area and eight-area configurations, respectively) using a skull model. The two dynamic navigation systems (X-Guide and Navident) and the two registration methods (bone surface tracing and fiducial markers) produced four registration groups: XG tracing, ND tracing, XG fiducial, and ND fiducial. The accuracy of the registration was checked at the frontal process of the zygoma. Intra- and interoperator reliabilities were reported for each registration group. Multiple comparisons were conducted to find the best configuration with the minimum registration error. RESULTS: Ranking revealed one configuration in the tracing groups (Conf.3) and two configurations in the fiducial groups (Conf.3 and Conf.5) that had the best accuracy. When the inferior surfaces of the zygomatic buttress were excluded, fiducial registration produced better accuracy with both systems (P = .006 and < .0001). However, bilaterally tracing 1-cm areas at these surfaces resulted in similar registration accuracy to placing fiducial markers there (P = .430 and .237). Navident performed generally better (P = .049, .001, and .002), but the values had a wider margin of uncertainty. Changing the distribution of the four tracing areas or fiducial markers had a less pronounced effect with the X-Guide than with the Navident system. CONCLUSIONS: For surgery in the edentulous maxilla, four fiducial markers placed according to Conf.3 or Conf.5 resulted in the lowest registration error. Where implants are being placed bilaterally, an additional two sites may further reduce the error. For bilateral zygomatic implant placement, it is optimal to place two fiducial markers on the inferior surfaces of the maxillary tuberosities, two on their buccal surfaces, and another two on the anterior labial surface of the alveolar bone. Utilizing the inferior zygomatic buttress is recommended over the inferior maxillary tuberosities in other types of maxillary surgeries.

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.

Improvement in facial aesthetics of orthognathic patients after surgery-first approach.

Facial appearance significantly affects psychosocial wellbeing, and an improvement in facial aesthetics is considered an essential outcome of orthognathic treatment. The surgery-first approach (SFA) has emerged as a promising alternative to the conventional orthodontics-first approach (OFA) due to its potential advantages in reducing treatment duration and cost, delivering early aesthetic improvement, and increasing patient satisfaction. However, its impact on final facial aesthetics and how it compares with the OFA has, to our knowledge, not yet been investigated. This retrospective study aimed to compare the improvement in facial aesthetics after orthognathic surgery in an SFA and an OFA group. Preoperative and postoperative 3-dimensional stereophotogrammetry facial images of 40 patients were evaluated by five professional assessors using the Global Aesthetic Improvement Scale (GAIS). Similar aesthetic improvement outcomes were found in both the SFA and OFA groups. The GAIS score significantly correlated with the following facial variables: upper lip projection, chin prominence, facial proportions, paranasal hollowing, lip competence, mandibular projection, and facial profile. No significant correlation was found between a change in aesthetic score and the surgical variables. There was a positive association between overall GAIS score and the gender and experience level of the individual assessors. This study suggests that aesthetic facial improvement achieved with the SFA is satisfactory and comparable to that of the OFA.

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.

Dynamic navigation for zygomatic implant placement: A randomized clinical study comparing the flapless versus the conventional approach.

OBJECTIVES: The assessment of the accuracy of flapless placement of zygomatic implants in edentulous maxilla using dynamic navigation. METHODS: A randomized controlled trial was carried out on 20 patients. Patients were randomized into two groups, the flapless (Group 1; n=10) and the conventional (Group 2; n=10). In each case two zygomatic implants were inserted under local anaesthesia, one on the right and one on the left side guided by a dynamic navigation system. The surgical procedure was identical in the two groups except for the reflection of the mucoperiosteal flap which was eliminated in the flapless cases. Postoperative CBCT scans were used to assess the accuracy of the placement of zygomatic implants. RESULTS: Osseointegration was achieved for all the implants, except one case in the flapless group. Statistically significant differences in the accuracy of the position of the zygomatic implants was found between the flapless and the conventional groups, measured at the apex and the entry points of the implants (p < 0.01). The average apical and coronal deviations were 5 mm and 3 mm, respectively; the angular deviation was 6°, and 2 mm vertical apical disparity was detected between the planned and the achieved surgical position. Perforation of the Schneiderian membrane was noted in three cases, one in flapless group and two in the conventional group. CONCLUSIONS: Flapless placement of zygomatic implants guided by dynamic navigation offered satisfactory safety and accuracy. CLINICAL SIGNIFICANCE: This is the first clinical trial to prove the feasibility and accuracy of flapless placement of zygomatic implant with minimal morbidity. The study highlights the innovative reflection of the Schneiderian membrane under guided surgical navigation. The procedure can be performed under local anaesthesia, which offers clinical advantages. Adequate training on the use of dynamic navigation is mandatory before its use in clinical cases.

Flapless placement of zygomatic implants using dynamic navigation: an innovative technical note.

Zygomatic implants are routinely used for the rehabilitation of the midface and edentulous maxilla; the procedure is carried out under general anaesthesia and requires the direct lifting of the Schneiderian membrane. A prefabricated surgical guide is usually used to direct the position of the zygomatic implants during surgery. This proof-of-concept study explored an innovative flapless approach for placement of zygomatic implants guided by dynamic navigation. Under local anaesthesia eight zygomatic implants were placed using a flapless technique. The preplanned position of zygomatic implants was transferred to the operating theatre using dynamic navigation, which guided the sinus lift procedure and the planned osteotomy. Operative complications were recorded, the accuracy of the implant position was measured and postoperative morbidities including pain and swelling were evaluated. Surgical complications were minimal, the Schneiderian membrane was intact in all the cases except one, which required the application of resorbable collagen membrane. Satisfactory accuracy was achieved regarding the precision of implant position and angulation. One of the patients developed maxillary sinusitis three months following surgery. Postoperative pain and swelling were minimal. The dynamic navigation guided flapless placement of zygomatic implants under local anaesthesia is a feasible technique with minimal surgical complications and postoperative morbidities.

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.

Cost-effectiveness of the Flapless Insertion of Zygomatic Implants Using Dynamic Navigation - A Retrospective Study.

Introduction: Zygomatic implants are an effective solution for rehabilitation of edentulous atrophic maxillae. However, the conventional technique of zygomatic implant placement is invasive, requires a longer healing period and is economically cumbersome. Therefore, the flapless technique of insertion of zygomatic implants using dynamic navigation system has been introduced. This study aims to compare the cost-effectiveness of flapless insertion of zygomatic implants using dynamic navigation to the conventional flap technique. Materials and Methods: The study participants were divided into two groups: Group A (n = 20) included patients treated by flapless insertion of zygomatic implants using dynamic navigation and Group B (n = 20) included patients treated with zygomatic implants using the flap technique. An analysis of the effectiveness of the implants was done using the concept of quality-adjusted prosthesis years, and an analysis of the costs was done by evaluating the treatment costs at each step. The data were collected, and analysis was done using IBM SPSS software. The Kruskal-Wallis rank-sum test was employed to analyse variations in costs and effects between the two groups. Results: The study showed that the distribution of costs varies across both the categories of the procedure. Group B shows lesser cost-effectiveness as compared to Group A. Conclusion: The technique of flapless insertion of zygomatic implants is cost-effective. However, further studies considering factors such as time and cost of productivity evaluating the cost-effectiveness should be conducted.

Pattern of pterygomaxillary disarticulation associated with Le Fort I maxillary osteotomy.

Pterygomaxillary disarticulation (PMD) contributes to surgical complications of Le Fort 1 osteotomy and is associated with undesirable fractures of the pterygoid plates. The aim of this paper was to investigate the patterns of PMD in Le Fort I osteotomies using Rowe's disimpaction forceps, and to evaluate correlations with age and anatomical measurements. Cone-beam computed tomography (CBCT) scans of 70 consecutive orthognathic patients were retrospectively evaluated to study four patterns of PMD: Type 1 - PMD at, or anterior to, the pterygomaxillary junction (PMJ); Type 2 - PMD posterior to the PMJ; Type 3 - PMJ separation with comminuted fracture of the pterygoid plates; Type 4 - disarticulation of the maxilla involving the pterygoid plates above the level of the osteotomy line. The preoperative anteroposterior and mediolateral thicknesses of the PMJ and the length of the medial and lateral pterygoid plates were assessed. Satisfactory PMD was achieved in all cases and no severe complications were reported, including vascular, dental, mucosal, or neural damage. The most common PMD was Type 1 (54.3%), followed by Type 2 (40%). Comminuted fracture of the pterygoid plates was limited to 5.7% of cases, and no Type 4 was detected. A weak correlation was detected between PMJ thickness and PMD pattern (p = 0.04). No statistically significant correlation was detected between patients' age and type of PMD. PMD of Le Fort I maxillary osteotomy using a Smith spreader and Rowe's disimpaction forceps proved safe, with minimal damage to the pterygoid plates.

Surgery-first approach for correction of class III dentofacial deformity with Le Fort I osteotomy; is it advantageous?

The surgery-first approach (SFA) to orthognathic treatment aims to reduce its duration without compromising the outcome. However, the objective assessment of the achieved occlusion has been limited. This study was designed to assess the treatment duration, outpatient appointment number, and quality of occlusal outcomes for two groups of patients; one treated with the SFA and the other with an orthodontics-first approach (OFA). We carried our a retrospective cohort study of case records for twenty consecutive SFA, and 23 consecutive OFA, cases with class III malocclusions, treated with Le Fort I maxillary osteotomy only. Pre-and post-treatment study models were assessed using the Peer Assessment Rating (PAR). Significant differences (p<0.001) were found between the median active treatment durations (10.2 months for the SFA and 32.5 months for the OFA) and appointment numbers (14 for SFA and 24 for OFA). Median absolute PAR reductions were 40 for the SFA and 39 for the OFA. There was no significant difference between the groups regarding quality of occlusal correction. Treatment durations for the SFA group were significantly shorter than for the OFA group, with fewer outpatient appointments. The quality of occlusal outcome for both SFA and OFA groups were satisfactory and comparable.

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.

The Characterisation of the Craniofacial Morphology of Infants Born With Zika Virus; Innovative Approach for Public Health Surveillance and Broad Clinical Applications.

Background: This study was carried out in response to the Zika virus epidemic, which constituted a public health emergency, and to the 2019 WHO calling for strengthened surveillance for the early detection of related microcephaly. The main aim of the study was to phenotype the craniofacial morphology of microcephaly using a novel approach and new measurements, and relate the characteristics to brain abnormalities in Zika-infected infants in Brazil to improve clinical surveillance. Methods: 3D images of the face and the cranial vault of 44 Zika-infected infants and matched healthy controls were captured using a 3D stereophotogrammetry system. The CT scans of the brain of the infected infants were analysed. Principal component analysis (PCA) was applied to characterise the craniofacial morphology. In addition to the head circumference (HC), a new measurement, head height (HH), was introduced to measure the cranial vault. The level of brain abnormality present in the CT scans was assessed; the severity of parenchymal volume loss and ventriculomegaly was quantified. Student's t-test and Spearman's Rho statistical test have been applied. Findings: The PCA identified a significant difference (p < 0.001) between the cranial vaults and the face of the Zika infants and that of the controls. Spearman's rank-order correlation coefficients show that the head height (HH) has a strong correlation (0.87 in Zika infants; 0.82 in controls) with the morphology of the cranial vaults, which are higher than the correlation with the routinely used head circumference (HC). Also, the head height (HH) has a moderate negative correlation (-0.48) with the brain abnormalities of parenchymal volume loss. Interpretation: It is discovered that the head height (HH) is the most sensitive and discriminatory measure of the severity of cranial deformity, which should be used for clinical surveillance of the Zika syndrome, evaluation of other craniofacial syndromes and assessment of various treatment modalities.

Orthognathic patient perception of 3D facial soft tissue prediction planning.

The primary aim of this study was to explore patients' perceptions regarding the impact of 3D prediction planning (3D PP) of facial soft tissue changes following orthognathic surgery. The study was carried out on 30 patients who were shown photorealistic 3D soft tissue prediction planning before undergoing orthognathic surgery to demonstrate the expected facial changes. Distraction osteogenesis and cleft deformities were excluded from the study before consenting to surgery. Following surgery, the included patients were asked to complete a standard questionnaire to explore their perceptions regarding the impact, accuracy, and value of 3D prediction planning. The majority of the 30 participants perceived 3D PP to be beneficial in reducing their presurgical anxiety, increasing their motivation to undergo surgery, improving the accuracy of their surgical expectations, and enhancing doctor-patient communication. Most of the patients perceived their surgical soft tissue changes to be better than the predictions. Significant positive correlations were detected between satisfaction with the delivered service and the facility of seeing 3D PP (rs = 0.4; p = 0.034). Similarly, 3D PP improved patients' confidence in the surgical decision (rs = 0.4; p = 0.031), as well as increasing their motivation to undergo surgery (rs = 0.5; p = 0.010). 3D PP was found to be effective in improving the quality of orthognathic surgical care.

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.

Comparative analysis for five fixations of Pauwels-I by the biomechanical finite-element method.

Background: Little is known about how biomechanics govern the five fixtures such as DHS, MLS, DHS + LS, LP, and HA are accepted as common therapeutic techniques. Aims and objectives: A series of numerical models for a femoral neck fracture of Pauwels-I will be constructed by innovative approach of finite element in order to determine the most optimized option in comparison with biomechanical performance. Method: Twenty sets of computer tomography scanned femora were imported onto Mimics to extract 3 D models; these specimens were transferred to Geomagic-Studio for a simulative osteotomy and kyrtograph; then, they underwent UG to fit simulative solid models; 5 sorts of fixture were then expressed by Pro-Engineer virtually. After processing with HyperMesh, all compartments (fracture model + internal implant) were assembled onto 5 systems: "Dynamic Hip Screw (DHS), Multiple Lag screw (MLS), DHS + LS, femoral Locking Plate (LP) and HemiArthroplasty (HA)." Eventually, numerical models of the finite-elemental analysis were exported to AnSys to determine the solution. Result: Four models of fixation and a simulation of HA for Pauwels-I were established, validated, and analyzed with the following findings: In term of displacement, these 5 fixtures ranged between 0.3801 and 0.7536 mm have no significant difference; in term of stress, the averages of peaks for integral assemblage are b(MLS) = 43.5766 ≈< d(LP) = 43.6657 ≈< e(Ha) = 43.6657 < c(DHS + LS) = 66.5494 < a(DHS) = 105.617 in MPa indicate that MLS, LP and HA are not significantly different, but less than DHS + LS or DHS in each. Conclusion: A fixture of MLS or LP with optional HA should be recommended to clinically optimize a Pauwels-I facture.

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.

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.