Facial Asymmetry Caused by Mandibular Condylar Hyperplasia: A Two Center Study.

BACKGROUND: Condylar hyperplasia is a non-neoplastic overgrowth of the mandibular condyle. The disorder is progressive and causes gradual jaw deviation, facial asymmetry, and dental malocclusion. The only treatment capable of stopping hyperplastic growth is surgical condylectomy to remove the upper portion of the condyle containing the deranged growth center. When this procedure is conducted in proportion to the length of the healthy side it may also correct the jaw deviation and facial asymmetry. OBJECTIVES: To assess the degree to which condylectomy corrects the asymmetry and to determine the proportion of patients after condylectomy who were satisfied with the esthetic result and did not desire further corrective surgery. METHODS: We conducted a retrospective analysis of medical records of patients who underwent condylectomy that was not followed by corrective orthognathic surgery for at least 1 year to determine the degree of correction of chin deviation and lip cant. Patient satisfaction from treatment or desire and undergo further corrective surgery was reported. RESULTS: Chin deviation decreased after condylectomy from a mean of 4.8° to a mean of 1.8° (P < 0.001). Lip cant decreased after condylectomy from a mean of 3.5° to a mean of 1.5° (P < 0.001). Most patients (72%) were satisfied with the results and did not consider further corrective orthognathic surgery. CONCLUSIONS: Proportional condylectomy could be a viable treatment to both arrest the condylar overgrowth and achieve some correction of the facial asymmetry.

Effect of Orthognathic Surgery on Pre-existing Temporomandibular Disorders.

The management of patients with pre-existing temporomandibular disorders (TMDs) undergoing orthognathic surgery remains a subject of ongoing debate. This study aimed to profile these individuals and evaluate the correlation between orthognathic surgery and alterations in TMD indicators and symptoms. We conducted a retrospective cohort investigation involving patients with skeletal malocclusion and established TMDs. Variables of interest encompassed the performance of orthognathic surgery, documented TMDs (including temporomandibular joint (TMJ) sounds, TMJ pain, muscle discomfort, and jaw locking), and patients' self-assessments of TMJ and muscle pain using a visual analog scale (VAS). The primary outcome measures focused on changes in TMD indicators and symptoms. Among the study cohort, 73.4% exhibited skeletal class III malocclusion, while 26.6% presented with skeletal class II malocclusion. Notably, patients classified as skeletal class III were significantly younger than their skeletal class II counterparts (mean age: 23.06±5.37 vs. 26.71±7.33; P=0.034). The most prevalent pre-existing TMD complaint was TMJ sounds (65.5%), followed by TMJ pain (39.1%), muscle discomfort (23.4%), and jaw locking (12.5%). Skeletal class II patients were more likely to experience TMJ sounds compared to skeletal class III patients (88.2% vs. 57.4%; P=0.022). Statistically significant improvements were observed in the VAS assessments among class III patients following surgery. A majority of patients with pre-existing TMDs seeking orthognathic surgery exhibited skeletal class III malocclusion and were younger than those with skeletal class II malocclusion. Importantly, orthognathic surgery was associated with positive changes in TMD indicators and symptoms in these patients.

Chondrocytes supplemented to bone graft-containing scaffolds expedite cranial defect repair.

Critical maxillofacial bone fractures do not heal spontaneously, thus, often there is a need to facilitate repair via surgical intervention. Gold standard approaches, include the use of autologous bone graft, or devices supplemented with osteogenic growth factors and bone substitutes. This research aimed to employ a critical size calvaria defect model, to determine if the addition of chondrocytes to collagen-containing bone graft substitute, may expedite bone repair. As such, using a critical size rat calvaria defect, we implanted a collagen scaffold containing bone graft substitute (i.e., Bone graft scaffold, BG) or BG supplemented with costal chondrocytes (cBG). The rats were subjected to live CT imaging at 1, 6, 9, and 12 weeks following the surgical procedure and sacrificed for microCT imaging of the defect site. Moreover, serum markers and histological evaluation were assessed to determine osseous tissue regeneration and turnover. Live CT and microCT indicated cBG implants displayed expedited bone repair vs, BG alone, already at 6 weeks post defect induction. cBG also displayed a shorter distance between the defect edges and greater mineral apposition distance compared to BG. Summerizing, the data support the addition of chondrocytes to bone substitute, accelerates the formation of new bone within a critical size defect.

Deep learning for detection and 3D segmentation of maxillofacial bone lesions in cone beam CT.

OBJECTIVES: To develop an automated deep-learning algorithm for detection and 3D segmentation of incidental bone lesions in maxillofacial CBCT scans. METHODS: The dataset included 82 cone beam CT (CBCT) scans, 41 with histologically confirmed benign bone lesions (BL) and 41 control scans (without lesions), obtained using three CBCT devices with diverse imaging protocols. Lesions were marked in all axial slices by experienced maxillofacial radiologists. All cases were divided into sub-datasets: training (20,214 axial images), validation (4530 axial images), and testing (6795 axial images). A Mask-RCNN algorithm segmented the bone lesions in each axial slice. Analysis of sequential slices was used for improving the Mask-RCNN performance and classifying each CBCT scan as containing bone lesions or not. Finally, the algorithm generated 3D segmentations of the lesions and calculated their volumes. RESULTS: The algorithm correctly classified all CBCT cases as containing bone lesions or not, with an accuracy of 100%. The algorithm detected the bone lesion in axial images with high sensitivity (95.9%) and high precision (98.9%) with an average dice coefficient of 83.5%. CONCLUSIONS: The developed algorithm detected and segmented bone lesions in CBCT scans with high accuracy and may serve as a computerized tool for detecting incidental bone lesions in CBCT imaging. CLINICAL RELEVANCE: Our novel deep-learning algorithm detects incidental hypodense bone lesions in cone beam CT scans, using various imaging devices and protocols. This algorithm may reduce patients' morbidity and mortality, particularly since currently, cone beam CT interpretation is not always preformed. KEY POINTS: • A deep learning algorithm was developed for automatic detection and 3D segmentation of various maxillofacial bone lesions in CBCT scans, irrespective of the CBCT device or the scanning protocol. • The developed algorithm can detect incidental jaw lesions with high accuracy, generates a 3D segmentation of the lesion, and calculates the lesion volume.

Increased Prevalence of Generalized Joint Hypermobility Observed in Patients With Recurrent Temporomandibular Joint Dislocation.

BACKGROUND: Generalized joint hypermobility (GJH), determined by the Beighton score, is a fundamental part of diagnosing benign joint hypermobility syndrome (BJHS), which may also present extra-articular manifestations, and is determined by the Brighton criteria. PURPOSE: This study was designed to investigate whether there is an association between recurrent temporomandibular joint (TMJ) dislocation and these disorders. STUDY DESIGN, SETTING, AND SAMPLE: A retrospective cross-sectional study was conducted. Hospital-based patients with a history of recurrent TMJ dislocation were compared to population-based patients that did not experience TMJ dislocations or any other TMJ disorders. Age and sex matching were performed between the study groups. All subjects reached the age of skeletal maturity. PREDICTOR VARIABLE: A history of recurrent TMJ dislocations. MAIN OUTCOME VARIABLES: Measurements of Beighton score (range from 0 to 9 with a score of ≥ 4 indicating GJH) and correspondence to the Brighton criteria (with at least two "major" criteria or one "major" criterion plus two "minor" criteria or four "minor" criteria indicating BJHS). COVARIATES: Included age and sex. ANALYSES: Mann-Whitney U-test for continuous variables and the χ2 test or Fisher's exact test for categorical variables. Statistical significance was set at P < .05. RESULTS: A total of 68 participants were included, of whom 34 patients presented with recurrent TMJ dislocations compared with a control population of 34. The Mean participants were 31.35 ± 8.06 years, and 29.4% (n = 20) were males. Of the dislocation group, 16 (47.0%) patients had a Beighton score of 4 or higher. The Beighton sum score was significantly higher, with a TMJ dislocation group mean score of 3.06 ± 2.8, compared with a control score of 0.82 ± 1.1 (P = .001). A total of 58.8% (n = 20) of the TMJ dislocation group participants met the Brighton criteria versus none (0.0%) of the control group (P = .001). CONCLUSION: We found an association between recurrent TMJ dislocation and GJH. An association with BJHS was also found, based mainly on articular manifestations. Early detection of these disorders in patients suffering from recurrent TMJ dislocation may help identify individuals at increased risk for joint instabilities and allow the implementation of appropriate preventive management strategies.

"Proportional Condylectomy" for Vertical Condylar Hyperplasia Without Intermaxillary Elastics: Clinical Results and Patient Satisfaction.

OBJECTIVES: First, to investigate the clinical outcome of 'proportional condylectomy' for patients with active unilateral condylar hyperplasia without complementary treatment by intermaxillary elastics and, second, to examine their level of satisfaction regarding function and esthetics. STUDY DESIGN: A retrospective observational descriptive study was conducted. All patients included in the study suffered from active unilateral condylar hyperplasia with a vertical component. The length of the condylar-ramus unit was measured on both sides by an multidetector computed tomography scan. The difference was calculated and resected from the hyperplastic condyle during the operation. Facial, occlusal, and skeletal changes were evaluated using photographic and radiologic records, and a satisfaction questionnaire regarding function and esthetics was completed. P <0.05 was considered significant. RESULTS: Fifteen patients were included in the study. The mean participants' age was 27.93±13.06 years, and the mean follow-up duration was 12.40±6.55 months. The mean chin deviation improved by 58.47% ( P =0.001). Mean lip commissure plane tilt was improved by 61.31% ( P =0.001). Six months postoperatively, all patients exhibited centered dental midlines ( P =0.001). Occlusal plane tilt was significantly improved by 70.02% ( P =0.001), and high patient satisfaction was recorded. Twenty-six percent (4/15) of patients did not require the complementary orthodontic treatment, and none of them required complementary orthognathic surgery. CONCLUSIONS: 'Proportional condylectomy' for patients with active unilateral vertical condylar hyperplasia without complementary treatment by intermaxillary elastics is a predictable procedure in terms of function and esthetics.

Are There Cephalometric Measurements Associated With Recurrent Temporomandibular Joint Dislocation?

PURPOSE: Several theories have been proposed for the etiology of recurrent temporomandibular joint (TMJ) dislocation. The purpose of the present study was to determine whether there are cephalometric measurements associated with this phenomenon. METHODS: A retrospective case-control study was performed, which included individuals who suffered from recurrent TMJ dislocation and a control group composed of patients who suffered from unrelated odontogenic infections and did not have any TMJ disorder. All the patients were referred to the Department of Oral and Maxillofacial Surgery at the Hadassah Medical Center between 2010 and 2021 and underwent multidetector computed tomography of the jaws. The main predictor variable was a history of recurrent TMJ dislocations. Covariates included age and gender. The primary outcome variable was a set of 11 cephalometric measurements. A statistical analysis was performed with the Mann-Whitney U-test for continuous variables and the Chi-squared test or Fisher's exact test for categorical variables, followed by a logistic regression model. Multiple comparisons were made by using the Benjamini-Hochberg method. RESULTS: The total 32 subjects included in the analysis consisted of 16 patients presenting with bilateral recurrent TMJ dislocation and a control population of 16 patients. The mean age was 34.19 ± 12.7 years, 40.6% (n = 13) were males, with no statistically significant differences between the groups. An increased overbite was detected in the TMJ dislocation group, whereas over-jet was greater among the control group, although not statistically significant. Skeletal ratio analysis showed that the TMJ dislocation group had a statistically significantly greater Articulare-Gonion length (46.96 mm ± 5.2 mm vs 43.01 mm ± 5.3 mm; P = .043) and a lower angle of occlusal plane to Frankfort horizontal (4.56o ± 5.7o vs 9.60o ± 3.9o; P = .007), Y-axis (58.01o ± 4.9o vs 61.72o ± 3.3o; P = .019), and Frankfurt mandibular plane (24.10o ± 6.1o vs 30.14o ± 4.7o; P = .004). CONCLUSIONS: Specific cephalometric measurements are associated with recurrent TMJ dislocation. The high Articulare-Gonion length and the low rates of occlusal plane to Frankfort horizontal angle, Y-axis, and Frankfurt mandibular plane found in the study population suggest that the resultant vertically oriented elevator muscles may be considered a predisposing factor for this phenomenon.

Short Dental Implants (5 to 7 mm) with Expandable Apex in the Posterior Maxilla-Preliminary Results.

PURPOSE: The purpose of this study was to examine whether the use of short dental implants with an expandable compressive design could be a proper alternative to the conventional sinus elevation procedure in cases of deficient alveolar ridge height in the posterior maxillary area. MATERIALS AND METHODS: Fifty patients with 73 short dental implants with an expandable compressive design who were treated for posterior maxillary alveolar ridges of 5 to 7 mm in the vertical dimension between 2012 and 2018 were included in a retrospective study. All patients had a minimum postrehabilitation period of 1 year. Patient demographics, implant properties, primary stability, and implant success and survival rates were analyzed. RESULTS: The total success rate was 97.2%, with two failed implants at implant uncovering. The mean bone loss was 1.03 mm. No difference in bone loss was found between sexes or age groups. CONCLUSION: The results of this study suggest that short dental implants with an expandable apical compressive design could be an alternative to sinus elevation procedures in selected cases of vertically deficient maxillary alveolar ridges.

The influence of mandibular condyle morphology on TMJ anterior dislocations.

OBJECTIVES: The present study was designed to investigate the correlation between the bony morphology of the mandibular condyle and the occurrence of temporomandibular joint (TMJ) idiopathic anterior dislocation. STUDY DESIGN: A comparative retrospective study was conducted among 14 patients presenting idiopathic anterior dislocations (study group) and 15 patients who did not suffer from any TMJ disorders (control group). All patients underwent a multidetector computed tomography scan demonstrating the full extent of their joints. The scans of 58 joints were reconstructed and analyzed by tools available in Dolphine3 software. Mandibular condyle size and volume were measured, and its shape was characterized. RESULTS: Shape, width, length, height, and volume of the mandibular condyles did not differ statistically between the study and control groups. CONCLUSION: Mandibular condyle morphology does not affect TMJ idiopathic anterior dislocation.

The efficacy of a protective protocol for oral and maxillofacial surgery procedures in a COVID-19 pandemic area-results from 1471 patients.

OBJECTIVE: To examine the effectiveness of an empiric protection protocol during oral surgical treatments in a COVID-19 pandemic area and to evaluate the potential effect of postponed dental procedures on the frequency of facial infections during a lockdown period. METHODS: We performed a retrospective analysis of a case series of a broad-spectrum of oral surgeries in a COVID-19 pandemic area. Data collection included patient age, type of procedure performed, and COVID-19 status of staff and patients. Data were analyzed using descriptive statistics. RESULTS: Between February 21 and April 23, 2020, 1471 patients were treated in the outpatient clinic (n=1404) and under general anesthesia (n=67). All procedures were carried out under a strict empiric protective protocol that included patient screening, personal protective equipment allocation protocol, frequent staff testing, and patient testing before general anesthesia. Treatments included emergency and urgent elective procedures. Only one staff member was confirmed positive for COVID-19 during routine weekly testing, and an independent epidemiologic investigation suggested he was likely infected outside of hospital facilities. CONCLUSIONS: Our empiric protective protocol was found to be effective in preventing staff cross-infection with COVID-19 in an oral and maxillofacial surgery setting. CLINICAL RELEVANCE: To the best of our knowledge, this is the first report that provides data regarding oral surgical activity in a COVID-19 pandemic area. Our suggested protective protocol may assist oral surgeons in continuing dental services in a safe manner.

The influence of articular eminence morphology on temporomandibular joint anterior dislocations.

OBJECTIVE: The aim of this study was to investigate the correlation between the bony morphology of the articular eminence and the occurrence of idiopathic anterior temporomandibular joint (TMJ) dislocation. STUDY DESIGN: A comparative retrospective study was conducted in 14 patients with idiopathic anterior dislocations (study group) and 14 patients who did not suffer from any TMJ disorders (control group). All patients underwent multidetector computed tomography (MDCT), which demonstrated the full extent of their joints. The scans of 56 joints were reconstructed and analyzed by using the tools available in Dolphin 3 software. Gross morphology characteristics and fine morphologic characteristics were defined by measuring the articular eminence inclination and height on the lateral, middle, and medial aspects of the articular eminence. RESULTS: Gross and fine morphologic characteristics of the articular eminence did not differ statistically between the study group and the control group. CONCLUSIONS: Articular eminence morphology does not affect TMJ idiopathic anterior dislocation.

Nonfixated inlay graft for anterior localized mandibular defect.

Localized vertical bone defects within the anterior mandibular alveolar ridge frequently pose a unique challenge for functionally and aesthetically pleasing rehabilitation of this area. Causes for significant bone loss in this region may include periodontal disease, postextraction atrophy, trauma, and orthodontic treatment. In the presence of such a defect, ridge augmentation may be obligatory before installation of dental implants. Several surgical procedures, notably bone augmentation techniques, including guided bone regeneration, onlay bone grafting, and interpositional grafts, have been described. However, loss of a single incisor or a few incisors may render these methods complicated for surgical manipulation. In this article, we aim to report the outcome of 4 cases with localized vertical osseous deficits in the anterior mandible, treated by using a technique whereby we utilized the bony defect's margins through a vestibular approach to wedge inlay grafts without additional fixation or distraction hardware, thus overcoming the surgical difficulties and achieving a favorable outcome.

Indirect Bactericidal Properties of Recombinant Human Bone Morphogenetic Protein 2 In Vitro.

PURPOSE: Bone morphogenetic proteins (BMPs) are secreted cytokines and are involved in various metabolic functions and inflammatory processes in different organs. The purpose of this study was to investigate whether BMPs also possess antimicrobial properties in direct or indirect ways. MATERIALS AND METHODS: Antibacterial properties of recombinant human BMP2 (rhBMP2) were tested on 4 bacteria species (Staphylococcus aureus, Escherichia coli, Streptococcus mitis, Streptococcus constellatus) to examine the potential synergism of rhBMP2 with antibiotics. Indirect antibacterial properties were tested by infecting neutrophils with rhBMP2 and bacteria to investigate bacterial survival. Reactive oxidative species (ROS) production in neutrophils in the presence of rhBMP2 also was tested. RESULTS: RhBMP2 in cardboard disks or sponge collagen as carriers did not show antibacterial activity against all tested bacteria. Further, synergism of rhBMP2 with antibiotics was not evident. Survival of bacteria inoculated with neutrophils and rhBMP2 led to a marked decrease in bacterial survival compared with neutrophils without rhBMP2. Although rhBMP2 inoculation of neutrophils alone did not induce ROS, its presence with the bacterial infection showed augmented ROS production for all tested bacteria. CONCLUSIONS: RhBMP2 did not show direct antibacterial properties but did exhibit an indirect bactericidal effect in the presence of neutrophils. ROS production indicated that rhBMP2 has a role as a priming agent for neutrophils by augmenting their bactericidal capabilities and suggests the importance of its presence in contaminated surgical bone augmentation sites.

Successful Mandibular Mucormycosis Treatment in the Severely Neutropenic Patient.

PURPOSE: Mucormycosis is a rare opportunistic and aggressive deep fungal infection that predominantly affects immunocompromised patients, and its mortality rate has been reported as up to 80%. Typing of the infection is based mainly on clinical and anatomic presentations, with the most common being the rhinocerebral type. MATERIALS AND METHODS: This report presents 3 patients with cancer who had successful treatment of mandibular mucormycosis. Chemotherapy was administered 13 to 30 days before diagnosis of the infection, resulting in neutropenia in all patients. Each case is thoroughly presented from initial admission through its diagnosis and treatment sequence. RESULTS: Early surgical ablative treatment and antifungal treatment resulted in the resolution of infection in all patients. Absolute neutrophil count increased 7 to 8 days after surgical debridement. CONCLUSIONS: Bringing patients to the post-neutropenic state tremendously increases their odds for survival.

Mandibular reconstruction using stereolithographic 3-dimensional printing modeling technology.

Mandibular reconstruction can be challenging for the surgeon wishing to restore its unique geometry. Reconstruction can be achieved with titanium bone plates followed by autogenous bone grafting. Incorporation of the bone graft into the mandible provides continuity and strength required for proper esthetics and function and permitting dental implant rehabilitation at a later stage. Precious time in the operating room is invested in plate contouring to reconstruct the mandible. Rapid prototyping technologies can construct physical models from computer-aided design via 3-dimensional (3D) printers. A prefabricated 3D model is achieved, which assists in accurate contouring of plates and/or planning of bone graft harvest geometry before surgery. The 2 most commonly used rapid prototyping technologies are stereolithography and 3D printing (3DP). Three-dimensional printing is advantageous to stereolithography for better accuracy, quicker printing time, and lower cost. We present 3 clinical cases based on 3DP modeling technology. Models were fabricated before the resection of mandibular ameloblastoma and were used to prepare bridging plates before the first stage of reconstruction. In 1 case, another model was fabricated and used as a template for iliac crest bone graft in the second stage of reconstruction. The 3DP technology provided a precise, fast, and cheap mandibular reconstruction, which aids in shortened operation time (and therefore decreased exposure time to general anesthesia, decreased blood loss, and shorter wound exposure time) and easier surgical procedure.

A role for extracellular Na+ in the channel gating of native and recombinant kainate receptors.

Ionotropic glutamate receptors of the kainate and AMPA subtypes share a number of structural features, both topographical and in terms of stoichiometry. In addition, AMPA and kainate receptors share similar pharmacological and biophysical properties in that they are activated by common agonists and display rapid activation and desensitization characteristics. However, we show here that in contrast to AMPA receptor-mediated responses (native or recombinant GluR3 receptor), the response of native and recombinant (GluR6) kainate receptors to glutamate was drastically reduced in the absence of extracellular Na+ (i.e., when replaced by Cs+). Removal of Na+ increases the rate of desensitization, indicating that external Na+ modulates channel gating. Whereas the size of the substituting cation is important in mimicking the action of Na+ (Li+>K+>Cs+), modulation was voltage independent. These results indicate the existence of different gating mechanisms for AMPA and kainate receptors. By using chimeric AMPA-kainate receptors derived from GluR3 and GluR6, we have identified a key residue in the S2 segment of GluR6 (M770) that is largely responsible for the sensitivity of the receptor to external Na+. Thus, these results show the existence of a specific kainate receptor gating mechanism that requires external Na+ to be operative.