Reconstruction of Craniomaxillofacial Bone Defects with 3D-Printed Bioceramic Implants: Scoping Review and Clinical Case Series.

Reconstruction of craniomaxillofacial bone defects using 3D-printed hydroxyapatite (HA) bioceramic patient-specific implants (PSIs) is a new technique with great potential. This study aimed to investigate the advantages, disadvantages, and clinical outcomes of these implants in craniomaxillofacial surgeries. The PubMed and Embase databases were searched for patients with craniomaxillofacial bone defects treated with bioceramic PSIs. Clinical outcomes such as biocompatibility, biomechanical properties, and aesthetics were evaluated and compared to those of commonly used titanium or poly-ether-ether-ketone (PEEK) implants and autologous bone grafts. Two clinical cases are presented to illustrate the surgical procedure and clinical outcomes of HA bioceramic PSIs. Literature review showed better a biocompatibility of HA PSIs than titanium and PEEK. The initial biomechanical properties were inferior to those of autologous bone grafts, PEEK, and titanium but improved when integrated. Satisfactory aesthetic results were found in our two clinical cases with good stability and absence of bone resorption or infection. Radiological signs of osteogenesis were observed in the two clinical cases six months postoperatively. HA bioceramic PSIs have excellent biocompatible properties and imitate natural bone biomechanically and radiologically. They are a well-suited alternative for conventional biomaterials in the reconstruction of load-sharing bone defects in the craniomaxillofacial region.

Accuracy of surgical navigation for patient-specific reconstructions of orbital fractures: A systematic review and meta-analysis.

OBJECTIVE: This systematic review and meta-analysis aimed to review the recent literature on the technical accuracy of surgical navigation for patient-specific reconstruction of orbital fractures using a patient-specific implant, and to compare surgical navigation with conventional techniques. MATERIALS AND METHODS: A systematic literature search was conducted in PubMed (Medline), Embase, Web of Science, and Cochrane (Core Collection) databases on May 16, 2023. Literature comparing surgical navigation with a conventional method using postoperative three-dimensional computed tomography imaging was collected. Only articles that studied at least one of the following outcomes were included: technical accuracy (angular accuracy, linear accuracy, volumetric accuracy, and degree of enophthalmos), preoperative and perioperative times, need for revision, complications, and total cost of the intervention. MINORS criteria were used to evaluate the quality of the articles. RESULTS: After screening 3733 articles, 696 patients from 27 studies were included. A meta-analysis was conducted to evaluate volumetric accuracy and revision rates. Meta-analysis proved a significant better volumetric accuracy (0.93 cm3 ± 0.47 cm3) when surgical navigation was used compared with conventional surgery (2.17 cm3 ± 1.35 cm3). No meta-analysis of linear accuracy, angular accuracy, or enophthalmos was possible due to methodological heterogeneity. Surgical navigation had a revision rate of 4.9%, which was significantly lower than that of the conventional surgery (17%). Costs were increased when surgical navigation was used. CONCLUSION: Studies with higher MINORS scores demonstrated enhanced volumetric precision compared with traditional approaches. Surgical navigation has proven effective in reducing revision rates compared to conventional approaches, despite increased costs.

Autoimmune diseases and orthognathic surgery: A case series of 12 patients.

Autoimmune diseases result from the immune system attacking native cells and tissues due to the recognition of "self" antigens as foreign antigens. This group of disorders is associated with an increased risk of complications after surgical interventions, as the immune system may cause tissue destruction. The study aimed to investigate the risk of surgical complications in patients with autoimmune diseases, who are at a higher risk of complications due to their condition. Among 886 patients who underwent orthognathic surgery, twelve types of autoimmune diseases with 22 patients were identified. For this case-series study, 12 patients were selected with a follow-up period of at least two years. The surgical procedures were executed by a single surgical team, which involved single or multi-piece Le Fort I osteotomy, Hunsuck/Epker modification of bilateral sagittal split osteotomy (BSSO), and/or genioplasty. The recorded outcome variables were postoperative adverse events, including respiratory or blood-related complications, wound infection, neurosensory disturbances, temporomandibular joint (TMJ) complications, and relapse. Only two patients recovered after surgery without any postoperative complications, whereas others had delayed recovery from neurosensory disturbance (5/12), infection (5/12), TMJ complications (2/12), and other complications. The findings of this study suggest that patients with autoimmune diseases undergoing orthognathic surgery are at higher risk of complications, highlighting the importance of careful consideration of patient selection and risk stratification before surgical intervention. The study also emphasizes the importance of close postoperative follow-up to detect and manage complications promptly.

Trueness of cone-beam computed tomography-derived skull models fabricated by different technology-based three-dimensional printers.

BACKGROUND: Three-dimensional (3D) printing is a novel innovation in the field of craniomaxillofacial surgery, however, a lack of evidence exists related to the comparison of the trueness of skull models fabricated using different technology-based printers belonging to different cost segments. METHODS: A study was performed to investigate the trueness of cone-beam computed tomography-derived skull models fabricated using different technology based on low-, medium-, and high-cost 3D printers. Following the segmentation of a patient's skull, the model was printed by: (i) a low-cost fused filament fabrication printer; (ii) a medium-cost stereolithography printer; and (iii) a high-cost material jetting printer. The fabricated models were later scanned by industrial computed tomography and superimposed onto the original reference virtual model by applying surface-based registration. A part comparison color-coded analysis was conducted for assessing the difference between the reference and scanned models. A one-way analysis of variance (ANOVA) with Bonferroni correction was applied for statistical analysis. RESULTS: The model printed with the low-cost fused filament fabrication printer showed the highest mean absolute error ([Formula: see text]), whereas both medium-cost stereolithography-based and the high-cost material jetting models had an overall similar dimensional error of [Formula: see text] and [Formula: see text], respectively. Overall, the models printed with medium- and high-cost printers showed a significantly ([Formula: see text]) lower error compared to the low-cost printer. CONCLUSIONS: Both stereolithography and material jetting based printers, belonging to the medium- and high-cost market segment, were able to replicate the skeletal anatomy with optimal trueness, which might be suitable for patient-specific treatment planning tasks in craniomaxillofacial surgery. In contrast, the low-cost fused filament fabrication printer could serve as a cost-effective alternative for anatomical education, and/or patient communication.

Anatomically and mechanically accurate scala tympani model for electrode insertion studies.

The risk of insertion trauma in cochlear implantation is determined by the interplay between individual cochlear anatomy and electrode insertion mechanics. Whereas patient anatomy cannot be changed, new surgical techniques, devices for cochlear monitoring, drugs, and electrode array designs are continuously being developed and tested, to optimize the insertion mechanics and prevent trauma. Preclinical testing of these developments is a crucial step in feasibility testing and optimization for clinical application. Human cadaveric specimens allow for the best simulation of an intraoperative setting. However, their availability is limited and it is not possible to conduct repeated, controlled experiments on the same sample. A variety of artificial cochlear models have been developed for electrode insertion studies, but none of them were both anatomically and mechanically representative for surgical insertion into an individual cochlea. In this study, we developed anatomically representative models of the scala tympani for surgical insertion through the round window, based on microCT images of individual human cochleae. The models were produced in transparent material using commonly-available 3D printing technology at a desired scale. The anatomical and mechanical accuracy of the produced models was validated by comparison with human cadaveric cochleae. Mechanical evaluation was performed by recording insertion forces, counting the number of inserted electrodes and grading tactile feedback during manual insertion of a straight electrode by experienced cochlear implant surgeons. Our results demonstrated that the developed models were highly representative for the anatomy of the original cochleae and for the insertion mechanics in human cadaveric cochleae. The individual anatomy of the produced models had a significant impact on the insertion mechanics. The described models have a promising potential to accelerate preclinical development and testing of atraumatic insertion techniques, reducing the need for human cadaveric material. In addition, realistic models of the cochlea can be used for surgical training and preoperative planning of patient-tailored cochlear implantation surgery.

Performance of novice versus experienced surgeons for dental implant placement with freehand, static guided and dynamic navigation approaches.

Lack of evidence exists related to the investigation of the accuracy and efficacy of novice versus experienced practitioners for dental implant placement. Hence, the following in vitro study was conducted to assess the accuracy of implant positioning and self-efficacy of novice compared to experienced surgeons for placing implant using freehand (FH), pilot drill-based partial guidance (PPG) and dynamic navigation (DN) approaches. The findings revealed that DN significantly improved the angular accuracy of implant placement compared with FH (P < 0.001) and PPG approaches (P < 0.001). The time required with DN was significantly longer than FH and PPG (P < 0.001), however, it was similar for both novice and experienced practitioners. The surgeon's self-confidence questionnaire suggested that novice practitioners scored higher with both guided approaches, whereas experienced practitioners achieved higher scoring with PPG and FH compared to DN. In conclusion, implant placement executed under the guidance of DN showed high accuracy irrespective of the practitioner's experience. The application of DN could be regarded as a beneficial tool for novices who offered high confidence of using the navigation system with the same level of accuracy and surgical time as that of experienced practitioners.

Three-dimensional planning accuracy and follow-up of Le Fort I osteotomy in cleft lip/palate patients.

OBJECTIVES: Our aim was to determine the accuracy of the three-dimensional (3D) virtual planning and stability of LeFort I osteotomy in cleft lip and/or palate patients (CLP) using a validated 3D method. MATERIALS AND METHODS: Eight patients with a history of cleft lip/palate treated with LeFort I osteotomy for maxillary hypoplasia between January 2016 and April 2020 were included in this retrospective study. Three-dimensional virtual planning was performed using Proplan software then transferred to the operation theater via 3D printed occlusal wafers. The accuracy of the 3D planning and the 1-year stability of the maxilla were evaluated by means of a validated semiautomatic stepwise module in Amira software resulting into 3 linear measurements: anterior/posterior, medial/lateral, superior/inferior and 3 rotational measurements: pitch, roll, yaw. RESULTS: The largest mean absolute difference (MAD) for accuracy assessment was found in the A/P direction (2.75mm±2.25 mm) and in pitch (3.23°±2.11°). For A/P translation, an error of >2 mm was observed in 5(62.5%), for S/I translation an error of >2 mm was observed in 4(50.0%) of the 8 patients, whereas for pitch 3 patients(37,5%) showed an error >4° At one year follow-up, the largest linear and rotational MAD was found in the A/P direction (1.20mm±0.92 mm) and in pitch (3.31°±2.31°). CONCLUSIONS: Findings of this study show that 3D virtual computer-assisted orthognathic surgery enables an accurate repositioning of the hypoplastic maxilla in CLP patients. However, A/P translations and pitch rotations remain challenging to achieve during surgery. These movements were also found to be least stable at one year follow-up.

Postoperative complications in asthmatic patients following orthognathic surgery: A two-year follow-up study.

BACKGROUND: Lack of evidence exists related to the incidence of postoperative complications in asthmatic patients following orthognathic surgery. The present study aimed to assess the incidence and risk factors of postoperative complications in asthmatic patients following orthognathic surgery. MATERIAL AND METHODS: A retrospective cohort study was conducted which consisted of two groups of patients i.e., asthmatic and systemically healthy patients, who underwent conventional orthognathic surgical procedures (Le Fort I osteotomy, bilateral sagittal split osteotomy, and genioplasty). The recorded postoperative complications in both groups of patients included infection, relapse, altered facial sensation, temporomandibular joint disorder, respiratory complications, and hemorrhage-related events. The association between baseline variables and complications for identifying the possible risk factors was assessed using bivariate analysis and a logistic regression model. RESULTS: A total of 886 patients underwent orthognathic surgery over a period of 6-years. Following the eligibility criteria, 16 patients were recruited in the asthmatic group and 278 patients were systemically healthy. The most common complications in the asthmatic patients were altered sensation (37.5%) followed by TMJ disorder (25.0%) and relapse (18.8%). These patients were associated with an increased risk of relapse (P = 0.048) compared to healthy patients. Following adjustment of baseline variables, increased risk of relapse was still associated with asthma (odds ratio [OR]. = 4.704, P = 0.027). CONCLUSION: Asthmatic patients suffer from a significantly higher risk of relapse and need to be closely monitored following orthognathic surgery to ensure a stable outcome. Asthma does not seem to have a significant impact on other postoperative complications.

Deep convolutional neural network-based automated segmentation and classification of teeth with orthodontic brackets on cone-beam computed-tomographic images: a validation study.

OBJECTIVE: Tooth segmentation and classification from cone-beam computed tomography (CBCT) is a prerequisite for diagnosis and treatment planning in the majority of digital dental workflows. However, an accurate and efficient segmentation of teeth in the presence of metal artefacts still remains a challenge. Therefore, the following study aimed to validate an automated deep convolutional neural network (CNN)-based tool for the segmentation and classification of teeth with orthodontic brackets on CBCT images. METHODS: A total of 215 CBCT scans (1780 teeth) were retrospectively collected, consisting of pre- and post-operative images of the patients who underwent combined orthodontic and orthognathic surgical treatment. All the scans were acquired with NewTom CBCT device. A complete dentition with orthodontic brackets and high-quality images were included. The dataset were randomly divided into three subsets with random allocation of all 32 tooth classes: training set (140 CBCT scans-400 teeth), validation set (35 CBCT scans-100 teeth), and test set (pre-operative: 25, post-operative: 15 = 40 CBCT scans-1280 teeth). A multiclass CNN-based tool was developed and its performance was assessed for automated segmentation and classification of teeth with brackets by comparison with a ground truth. RESULTS: The CNN model took 13.7 ± 1.2 s for the segmentation and classification of all the teeth on a single CBCT image. Overall, the segmentation performance was excellent with a high intersection over union (IoU) of 0.99. Anterior teeth showed a significantly lower IoU (P < 0.05) compared to premolar and molar teeth. The dice similarity coefficient score of anterior (0.99 ± 0.02) and premolar teeth (0.99 ± 0.10) in the pre-operative group was comparable to the post-operative group. The classification of teeth to the correct 32 classes had a high recall rate (99.9%) and precision (99%). CONCLUSIONS: The proposed CNN model outperformed other state-of-the-art algorithms in terms of accuracy and efficiency. It could act as a viable alternative for automatic segmentation and classification of teeth with brackets. CLINICAL SIGNIFICANCE: The proposed method could simplify the existing digital workflows of orthodontics, orthognathic surgery, restorative dentistry, and dental implantology by offering an accurate and efficient automated segmentation approach to clinicians, hence further enhancing the treatment predictability and outcomes.

The usefulness of cutting guides for resection or biopsy of mandibular lesions: A technical note and case report.

The application of three dimensional (3D) printed patient specific cutting guide for biopsy of a mandibular lesion closely positioned to the mandibular canal is presented. To prevent inferior alveolar nerve damage, the cutting site of the bone window was virtually planned and then the cutting guide was 3D printed. This guide enabled intra-operative control and resulted in absence of postoperative hypo- or dysesthesia. This case demonstrates that 3D printed patient specific guides can help reduce the risk of hypoesthesia in mandibular surgery.

Automated three-dimensional quantification of external root resorption following combined orthodontic-orthognathic surgical treatment. A validation study.

OBJECTIVE: Three-dimensional (3D) quantitative assessment of external root resorption (ERR) following combined orthodontic-orthognathic surgical treatment is vital for ensuring an optimal long-term tooth prognosis. In this era, lack of evidence exists applying automated 3D approaches for assessing ERR. Therefore, this study aimed to validate a protocol for 3D quantification of ERR on cone-beam computed tomography (CBCT) images following combined orthodontic-orthognathic surgical treatment. MATERIAL AND METHODS: Twenty patients who underwent combined orthodontic-orthognathic surgical treatment were recruited. Each patient had CBCT scans acquired with NewTom VGi evo (NewTom) at three time-points i.e., 4-weeks prior to surgery (T0), 1-week (T1) and 1-year after surgery (T2). Patients were divided into two groups, group A (surgical Le Fort I osteotomy group: 10 patients) and group B (orthodontic group without maxillary surgical intervention: 10 patients). Root resorption was assessed by measuring length and volumetric changes of maxillary premolar to premolar teeth (central and lateral incisors, canines, 1st and 2nd premolars= 10 teeth) at T0-T1 and T0-T2 time intervals in both groups. The protocol consisted of convolutional neural network based segmentation followed by surface-based superimposition and automated 3D analysis. RESULTS: The intra-observer intra-class correlation coefficient (ICC) was found to be excellent (1.0) with an average error of 0 mm and 0 mm3 for assessing root length and volume, respectively. The entire protocol took 56.8 ± 7 s for quantifying ERR. Both group of patients showed negligible changes in length and volumetric ratio at T0-T1 time-interval. Furthermore, group A had lower ERR ratio with decreased root volume and length compared to group B at T0-T2 time-interval. CONCLUSIONS: The proposed protocol was found to be time efficient, accurate and reliable for 3D quantification of ERR on CBCT images. It could act as a viable automated option for assessing ERR. CLINICAL SIGNIFICANCE: The automated protocol could provide a time efficient method to allow a reliable and accurate 3D follow up root resorption after orthognathic and orthodontic treatment procedures. These new insights could allow clinicians to implement strategies for minimizing the risk of root resorption and to further enhance treatment predictability.

Influence of experience on dental implant placement: an in vitro comparison of freehand, static guided and dynamic navigation approaches.

PURPOSE: This study aimed to investigate the performance of novice versus experienced practitioners for placing dental implant using freehand, static guided and dynamic navigation approaches. METHODS: A total of 72 implants were placed in 36 simulation models. Three experienced and three novice practitioners were recruited for performing the osteotomy and implant insertion with freehand, surgical guide (pilot-drill guidance) and navigation (X-Guide, X-Nav technologies) approaches. Each practitioner inserted 4 implants per approach randomly with a 1-week gap to avoid memory bias (4 insertion sites × 3 approaches × 6 practitioners = 72 implants). The performance of practitioners was assessed by comparing actual implant deviation to the planned position, time required for implant placement and questionnaire-based self-confidence evaluation of practitioners on a scale of 1-30. RESULTS: The navigation approach significantly improved angular deviation compared with freehand (P < 0.001) and surgical guide (P < 0.001) irrespective of the experience. Surgical time with navigation was significantly longer compared to the freehand approach (P < 0.001), where experienced practitioners performed significantly faster compared to novice practitioners (P < 0.001). Overall, self-confidence was higher in favor of novice practitioners with both guided approaches. In addition, the confidence of novice practitioners (median score = 26) was comparable to that of experienced practitioners (median score = 27) for placing implants with the navigation approach. CONCLUSIONS: Dynamic navigation system could act as a viable tool for dental implant placement. Unlike freehand and static-guided approaches, novice practitioners showed comparable accuracy and self-confidence to that of experienced practitioners with the navigation approach.

Postoperative complications following orthognathic surgery in patients with rheumatic diseases: A 2-year follow-up study.

OBJECTIVE: The purpose of this study was to describe the complications following orthognathic surgery in patients with rheumatic diseases and to evaluate rheumatic disease as a possible risk factor. METHODS: A retrospective cohort study was conducted during a 6-year period. The sample consisted of rheumatic and healthy patients who underwent orthognathic surgery. The outcome variables included infection, relapse, respiratory complications, hemorrhage, neurosensory disturbances, temporomandibular joint complications, and removal of osteosynthesis material. Bivariate analysis and logistic regression were applied to identify rheumatic disease as an independent risk factor for complications after orthognathic surgery. RESULTS: Twenty patients were identified as having rheumatic diseases (male: 2; female: 18; mean age: 37.8 ± 13.6 years), and 278 patients were systemically healthy (male: 105; female: 173; mean age: 25.8 ± 11.8 years). The most frequent complications in rheumatic and healthy patients were delayed recovery from neurosensory disturbance (55% and 33%), removal of osteosynthesis material (45% and 26%), and infection (35% and 7%). Following adjustment for possible confounders, rheumatic disease showed a significant association with infection (OR = 4.191, p = 0.016). CONCLUSION: Patients with rheumatic diseases are at a higher risk of postoperative infection following orthognathic surgery compared to healthy patients.

Deep convolutional neural network-based automated segmentation of the maxillofacial complex from cone-beam computed tomography:A validation study.

OBJECTIVES: The present study investigated the accuracy, consistency, and time-efficiency of a novel deep convolutional neural network (CNN) based model for the automated maxillofacial bone segmentation from cone beam computed tomography (CBCT) images. METHOD: A dataset of 144 scans was acquired from two CBCT devices and randomly divided into three subsets: training set (n = 110), validation set (n = 10) and testing set (n = 24). A three-dimensional (3D) U-Net (CNN) model was developed, and the achieved automated segmentation was compared with a manual approach. RESULTS: The average time required for automated segmentation was 39.1 s with a 204-fold decrease in time consumption compared to manual segmentation (132.7 min). The model was highly accurate for identification of the bony structures of the anatomical region of interest with a dice similarity coefficient (DSC) of 92.6%. Additionally, the fully deterministic nature of the CNN model was able to provide 100% consistency without any variability. The inter-observer consistency for expert-based minor correction of the automated segmentation observed an excellent DSC of 99.7%. CONCLUSION: The proposed CNN model provided a time-efficient, accurate, and consistent CBCT-based automated segmentation of the maxillofacial complex. CLINICAL SIGNIFICANCE: Automated segmentation of the maxillofacial complex could act as an alternative to the conventional segmentation techniques for improving the efficiency of the digital workflows. This approach could deliver accurate and ready-to-print3D models, essential to patient-specific digital treatment planning for orthodontics, maxillofacial surgery, and implant dentistry.

Accuracy of virtual planning and intraoperative navigation in zygomaticomaxillary complex fractures: A systematic review.

OBJECTIVE: This systematic review aims to investigate the effect of virtual planning on the treatment of zygomaticomaxillary complex (ZMC) traumatology followed by intraoperative navigation. Furthermore, clinical outcomes following intraoperative navigation surgery or conventional surgery will be compared. MATERIALS AND METHODS: A systematic literature search was conducted in PubMed, Embase, Web-of-Science, and Cochrane on January 1st, 2022. Inclusion criteria were articles using preoperative three-dimensional (3D) virtual planning combined with intraoperative navigation or comparing these 3D methods with conventional methods. Furthermore, at least one of the following outcomes needed to be included in the article: technical accuracy of the procedure, preoperative planning time, operative time, number of fixation points, patient satisfaction, complications, or total costs of the intervention. RESULTS: Following the screening of 4478 articles, 17 were included. Five articles appeared to indicate a significantly better technical linear accuracy, one article reported better accuracy for rotation and two articles showed better accuracy in restoring orbital volume when using navigation. Nine articles investigated operative time with varying results. Seven articles calculated the additional costs, of which three concluded no extra cost while the others indicated high additional costs or questionable cost-effectiveness. CONCLUSION: Virtual planning and intraoperative navigation technologies have the potential to assist maxillofacial trauma surgeons in reducing ZMC fractures significantly more accurately and restoring the facial contour in a less invasive manner at an acceptable cost. REGISTRATION: The protocol for this systematic review (CRD42020216717) was registered in the International Prospective Register of Systematic Reviews (PROSPERO).

Influence of systemic comorbidities on the complications of orthognathic surgery: A scoping review.

The potential impact of systemic comorbidities has not yet been thoroughly explored in orthognathic surgery. Therefore, the following scoping review was conducted to accumulate evidence on the possible impact of systemic comorbidities on the orthognathic surgery complications. PubMed, Embase, Cochrane, and Web of Science databases were searched up to April 2022 to identify studies about patients with systemic comorbidities who underwent orthognathic surgery. A total of 12,938 articles were screened, and seven articles met the inclusion criteria. Only one study had control group, other six articles had a non-comparative study design. The current evidence suggests a high impact of rheumatic diseases and neuromuscular disorders on the surgery- and patient-related postoperative complications following orthognathic surgery. At the same instance, the findings of the review should be interpreted with caution due to a lack of substantial evidence for extrapolating the findings to a contemporary surgical practice.

Incidence, Aetiology, and Associated Fracture Patterns of Infraorbital Nerve Injuries Following Zygomaticomaxillary Complex Fractures: A Retrospective Analysis of 272 Patients.

Study Design: Retrospective study. Objective: Zygomaticomaxillary complex (ZMC) fractures are common facial injuries with heterogeneity regarding aetiologies, fracture types, infraorbital nerve (ION) involvement, and treatment methods. The aim of this study was to identify associations between aetiologies, fracture types, and neurological complications. Additionally, treatment methods and recovery time were investigated. Methods: Medical files of 272 patients with unilateral and bilateral ZMC fractures were reviewed, whose cases were managed from January 2014 to January 2019 at the Department of Oral and Maxillofacial Surgery, University hospitals Leuven, Belgium. History of ION sensory dysfunction and facial nerve motoric dysfunction were noted during follow-up. Results: ION hypoaesthesia incidence was 37.3%, with the main causes being fall accidents, road traffic accidents, and interpersonal violence. Significant predictors of ION hypoaesthesia were Zingg type B fractures (P = 0.003), fracture line course through the infraorbital canal (P < .001), orbital floor fracture (P < 0.001), and ZMC dislocation or mobility (P = 0.001). Conclusion: Of all ZMC fractures, 37.3% exhibited ION hypoaesthesia. Only ZMC Zingg type B fractures (74.0%) were significantly more associated with ION hypoaesthesia. ION hypoesthesia was more likely (OR = 2.707) when the fracture line course ran through the infraorbital canal, and was less dependent on the degree of displacement. Neuropathic pain symptoms developed after ZMC fractures in 2.2% patients, posing a treatment challenge. Neuropathic pain symptoms were slightly more common among women, and were associated only with type B or C fractures. No other parameters were found to predict the outcome of this post-traumatic neuropathic pain condition.

Quality and haptic feedback of three-dimensionally printed models for simulating dental implant surgery.

STATEMENT OF PROBLEM: A model offering anatomic replication and haptic feedback similar to that of real bone is essential for hands-on surgical dental implant training. Patient-specific skeletal models can be produced with 3-dimensional (3D) printing, but whether these models can offer optimal haptic feedback for simulating implant surgery is unknown. PURPOSE: The purpose of this trial was to compare the haptic feedback of different 3D-printed models for simulating dental implant surgery. MATERIAL AND METHODS: A cone beam computed tomography image of a 60-year-old man with a partially edentulous mandible was manipulated to segment the mandible and isolated from the rest of the scan. Three-dimensional models were printed with 6 different printers and materials: material jetting-based printer (MJ, acrylic-based resin); digital light processing-based printer (DLP, acrylic-based resin); fused filament fabrication-based printer (FFF1, polycarbonate filament; FFF2, polylactic acid filament); stereolithography-based printer (SLA, acrylic-based resin); and selective laser sintering-based printer (SLS, polyamide filament). Five experienced maxillofacial surgeons performed a simulated implant surgery on the models. A 5-point Likert scale questionnaire was established to assess the haptic feedback. The Friedman test and cumulative logit models were applied to evaluate differences among the models (α=.05). RESULTS: The median score for drilling perception and implant insertion was highest for the MJ-based model and lowest for the SLS-based model. In relation to the drill chips, a median score of ≥3 was observed for all models. The score for corticotrabecular transition was highest for the MJ-based model and lowest for the FFF2-based model. Overall, the MJ-based model offered the highest score compared with the other models. CONCLUSIONS: The 3D-printed model with MJ technology and acrylic-based resin provided the best haptic feedback for performing implant surgery. However, none of the models were able to completely replicate the haptic perception of real bone.

Impact of orthognathic surgery on root resorption: A systematic review.

OBJECTIVE: This systematic review was performed to assess the potential influence of orthognathic surgery on root resorption (RR). MATERIAL AND METHODS: An electronic search was conducted using PubMed, Web of Science, Cochrane Central and Embase for articles published up to April 2022. Following inclusion and exclusion criteria, a total of six articles were selected that reported on RR following orthognathic surgery. Risk of bias assessment was performed according to the ROBINS-1 and ROB-2 tools. RESULTS: The design of five studies was retrospective and one randomized clinical trial was included, with a follow-up period ranging between six months and ten years. The assessment methodologies mostly relied on two-dimensional imaging modalities where only one study used cone-beam computed tomography (CBCT) for objective quantification via linear measurements. The percentage of teeth affected by RR varied between approximately 1 and 36%, where surgically assisted rapid maxillary expansion (SARME) and Le Fort I osteotomy showed the highest percentage of RR followed by bilateral sagittal split osteotomy. CONCLUSIONS: The present data tend to indicate that specific orthognathic procedures such as SARME and Le Fort I osteotomy may induce or reinforce RR. Yet, considering lack of evidence related to objective quantification of RR following orthodontic and/or orthognathic treatment, further CBCT-based prospective studies are required for an improved understanding of RR following different surgical procedures.

Three-Dimensional Pharyngeal Airway Space Changes Following Isolated Mandibular Advancement Surgery in 120 Patients: A 1-Year Follow-up Study.

Lack of evidence exists related to the three-dimensional (3D) pharyngeal airway space (PAS) changes at follow-up after isolated bilateral sagittal split osteotomy (BSSO) advancement surgery. The present study assessed the 3D PAS changes following isolated mandibular advancement at a follow-up period of 1 year. A total of 120 patients (40 males, 80 females, mean age: 26.0 ± 12.2) who underwent BSSO advancement surgery were recruited. Cone-beam computed tomography (CBCT) scans were acquired preoperatively (T0), immediately following surgery (T1), and at 1 year of follow-up (T2). The volume, surface area, and minimal cross-sectional area (mCSA) of the airway were assessed. The total airway showed a 38% increase in volume and 13% increase in surface area from T0 to T1, where the oropharyngeal region showed the maximum immediate change. At T1−T2 follow-up, both volumetric and surface area showed a relapse of less than 7% for all sub-regions. The mCSA showed a significant increase of 71% from T0 to T1 (p < 0.0001), whereas a non-significant relapse was observed at T1−T2 (p = 0.1252). The PAS remained stable at a follow-up period of 1 year. In conclusion, BSSO advancement surgery could be regarded as a stable procedure for widening of the PAS with maintenance of positive space at follow-up.