Imaging of mandibular fractures: a pictorial review

Delivery of A Jagged1-PEG-MAL hydrogel with Pediatric Human Bone Cells Regenerates Critically-Sized Craniofacial Bone Defects

Treatments for congenital and acquired craniofacial (CF) bone abnormalities are limited and expensive. Current reconstructive methods include surgical correction of injuries, short-term bone stabilization, and long-term use of bone grafting solutions, including implantation of (i) allografts which are prone to implant failure or infection, (ii) autografts which are limited in supply. Current bone regenerative approaches have consistently relied on BMP2 application with or without addition of stem cells. BMP2 treatment can lead to severe bony overgrowth or uncontrolled inflammation, which can accelerate further bone loss. Bone marrow-derived mesenchymal stem cell-based treatments, which do not have the side effects of BMP2, are not currently FDA approved, and are time and resource intensive. There is a critical need for novel bone regenerative therapies to treat CF bone loss that have minimal side effects, are easily available, and are affordable. In this study we investigated novel bone regenerative therapies downstream of JAGGED1 (JAG1). We previously demonstrated that JAG1 induces murine cranial neural crest (CNC) cells towards osteoblast commitment via a NOTCH non-canonical pathway involving JAK2-STAT5 (1) and that JAG1 delivery with CNC cells elicits bone regeneration in vivo. In this study, we hypothesize that delivery of JAG1 and induction of its downstream NOTCH non-canonical signaling in pediatric human osteoblasts constitute an effective bone regenerative treatment in an in vivo murine bone loss model of a critically-sized cranial defect. Using this CF defect model in vivo, we delivered JAG1 with pediatric human bone-derived osteoblast-like (HBO) cells to demonstrate the osteo-inductive properties of JAG1 in human cells and in vitro we utilized the HBO cells to identify the downstream non-canonical JAG1 signaling intermediates as effective bone regenerative treatments. In vitro, we identified an important mechanism by which JAG1 induces pediatric osteoblast commitment and bone formation involving the phosphorylation of p70 S6K. This discovery enables potential new treatment avenues involving the delivery of tethered JAG1 and the downstream activators of p70 S6K as powerful bone regenerative therapies in pediatric CF bone loss.

Reparative osteogenesis in mandible in cases of filling a bone defect with hydroxyapatite-containing osteotropic material and injecting the surrounding soft tissues with thymalin: experimental and morphological study

OBJECTIVE

Aim of the study was to identify the morphological features of reparative osteogenesis in the lower jaw bone of rats in cases of filling a bone defect with hydroxyapatite-containing osteotropic material (bone graft "Biomin GT") and injecting the surrounding soft tissues with thymalin.

PATIENTS AND METHODS

Materials and Methods: An experiment was conducted on 48 mature rats of the WAG population weighing 160-180 grams which were divided into four groups. Group 1 included 12 rats with a simulated holey defect in the lower jaw. Group 2 included 12 rats with a simulated holey defect in the lower jaw followed by its closure with hydroxyapatite-containing osteotropic material (bone graft "Biomin GT"). Group 3 included 12 rats with a simulated holey defect in the lower jaw with injecting the surrounding soft tissues with thymalin. Group 4 included 12 rats with a simulated holey defect in the lower jaw followed by its closure with hydroxyapatite-containing osteotropic material (bone graft "Biomin GT") and injecting the surrounding soft tissues with thymalin. The material for the morphological study was a fragment of the lower jaw from the area of the simulated holey defect. Histological, morphometric and statistical research methods were used.

RESULTS

Results: In this study, it was shown by the authors an activation of reparative osteogenesis in the lower jaw under conditions of simultaneous filling the bone defect with hydroxyapatite-containing osteotropic material (bone graft "Biomin GT") and injection the surrounding bone defect soft tissue with thymalin. Stimulation of reparative osteogenesis in the lower jaw of rats occurred due to rapid cleaning of the bone defect cavity from necrotic tissues and hematoma fragments; a decrease in the number of neutrophil leukocytes, an increase in the number and morphofunctional state of monocytes, macrophages, lymphocytes, cells of fibroblastic differon; balanced change (increase or decrease) in the number and morphofunctional state of bone forming osteoblasts and bone resorbing osteoclasts depending on the stage of reparative osteogenesis; activation of hematopoietic processes in lamellar bone tissue from the regenerate; activation of bone tissue mineralization processes.

CONCLUSION

Conclusions: Thymalin injection in the soft tissues surrounding the bone defect in the lower jaw, filled with hydroxyapatite-containing osteotropic material (bone graft "Biomin GT"), significantly stimulates the process of reparative osteogenesis, which makes it possible to recommend this technique in dentistry for treatment the patients with mandible bone tissue defects.

Characteristics and Complication Rates of Mandibular Fractures Caused by Violent Mechanisms Versus Nonviolent Mechanisms

Background

Mandibular fractures due to intentionally violent mechanisms represent a unique subset of facial fractures. The objective of our research is to identify how violence affects patterns of mandibular fractures and their outcomes.

Methods

In this institutional review board-approved, retrospective study, we examined our institution's records for adult patients >18 years of age who presented with ≥ 1 mandibular fractures from January 2011 to January 2022. Violence was defined as trauma intended to hurt another or self. Demographics, fractures, mechanism, concomitant injuries, treatment, and complications were analyzed with Excel and SPSS statistical software.

Results

A total of 692 patients were diagnosed with mandibular fractures, with 323 of these due to violence (47%). These patients of violence (POVs) had an average fracture per patient of 1.6 ± 0.7. The majority (88%) were male and African American (33%), and the average age was 34.3 ± 13.2 years. The most common violent mechanism was a punch (68%). The POVs presented with fewer concomitant injuries, were less likely to be admitted to the intensive care unit, and were more often surgically managed with open reduction than were patients of nonviolence (PONVs) (P < .01). POVs were more likely to have healing complications; though not statistically significant, this population was observed to be frequently lost to follow-up (P = .12). POVs notably had a much higher proportion of hardware exposure among complications than was seen in PONVs (23% vs 9%).

Conclusions

Patients with violent fracture mechanisms may tend to be predisposed to more complications compared with patients who have nonviolent fracture mechanisms despite lesser severities due to social determinants of health. Characteristics of this patient subset may tend to cause difficulties in postoperative care and follow-up. Effective discharge instruction communication, patient outreach programs, and homelessness and drug abuse screening in this subset may help reduce healing complications.

Evaluation of Joint Formation in Coronoid Process Hyperplasia (Jacob's Disease) on CT and MR Imaging

Background

Jacob's disease is a rare pathology characterized by elongation/ enlargement of coronoid process of mandible with formation of pseudoarticulation with zygomatic arch. It presents clinically as restricted mouth opening and is often misdiagnosed as temporomandibular joint pathology.

Case Presentation

We performed cross sectional imaging and evaluation of Jacob's disease in a 14-year-old girl with restricted mouth opening, CT images including Multiplanar Reconstruction and Volume Rendered Technique revealed enlarged left coronoid process of mandible while open mouth CT images and MR images concluded the presence of joint between enlarged coronoid process and zygomatic arch.

Conclusions

Coronoid process hypertrophy and Jacob's disease are important differentials which should be considered in evaluation of restricted mouth opening. We propose that apart from CT, MR imaging should be considered in such cases for better pre-operative evaluation of joint formation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-022-03323-7.

MORPHOLOGICAL CHARACTERISTICS OF REPARATIVE OSTEOGENESIS IN THE RATS LOWER JAW UNDER THE CONDITIONS OF USING ELECTRICAL STIMULATION

OBJECTIVE

Aim: The purpose of the study was to identify the morphological features of reparative osteogenesis in the rats lower jaw under the conditions of using electrical stimulation.

PATIENTS AND METHODS

Materials and Methods: An experiment was conducted on 24 mature male rats of the WAG population. Two groups were formed. Group 1 included 12 rats that were modeled with a perforated defect of the lower jaw body. Group 2 included 12 animals that were modeled with a perforated defect similar to group 1. In animals, a microdevice for electrical action was implanted subcutaneously in the neck area on the side of the simulated bone defect (a temporary Videx AG 4 battery; a constant sinusoidal electric current of an unchanging nature 1 milliampere, frequency 30 W). The negative electrode connected to the negative pole of the battery was in contact with the bone defect. The battery and electrode were insulated with plastic heat shrink material. Morphological and statistical methods were used.

RESULTS

Results: The positive effect of electrical stimulation on reparative osteogenesis was due to a decrease in the severity of hemodynamic disorders, activation of angiogenesis in granulation tissue, which was one of the components of the regenerate that filled the bone defect, matured and turned into connective tissue; stimulation of the proliferative potential of fibroblastic cells and cells with osteoblastic activity in granulation tissue; increasing the proliferative potential of osteoblastic elements of bone tissue bordering the cavity; stimulation of macrophage cells and processes of cleansing the bone cavity from fragments of a blood clot and alteratively changed tissues; formation of clusters of adipocytes in the loci of connective and granulation tissue of the regenerate; the process of metaplasia of connective tissue into bone tissue; an increase of the foci of hematopoiesis in the intertrabecular spaces of lamellar bone tissue.

CONCLUSION

Conclusions: A comprehensive clinical and experimental study conducted by the authors proved that electrical stimulation activates the reparative osteogenesis in the lower jaw, which occurs through direct osteogenesis and does not finish on the 28th day of the experiment.

CT characterisation and classification of feline temporomandibular joint trauma: a case series of 79 cats

OBJECTIVES

The aim of this study was to characterise and describe patterns of temporomandibular joint (TMJ) injuries occurring in cats using CT.

METHODS

A cross-sectional study was carried out in adherence with the STROBE guidelines. Among the medical and CT records of 79 cats, 158 TMJs were reviewed in a collaborative study between six institutions.

RESULTS

TMJ injuries were most commonly unilateral, representing 70.9% of cases. The mandibular condyle was fractured in 88 cases (55.7%) of the 158 TMJs observed. Of those, 84.0% were intra-articular condyle fractures, with the medial half of the mandibular condyle over-represented. Luxations occurred in 32.9% of cases, which was 19.0% of all evaluated TMJs. Rostrodorsal luxations were most common representing 87.0% of all luxations. Temporal bone fractures were observed in 30.4% of all cases, which was 18.4% of TMJs. The majority of fractures were of an unknown cause. When the cause was determined, road traffic accident (RTA) was the most frequent, followed by animal interaction, other external forces (sharp or blunt force) and high-rise trauma. Bilateral injuries were 13.1 times more likely to occur in high-rise trauma (P = 0.01) and temporal bone fracture was significantly associated with RTAs (P = 0.016). No other significant associations were observed between cause of injury and the resulting TMJ injury pattern.

CONCLUSIONS AND RELEVANCE

Various TMJ injury patterns can occur in cats as a result of trauma. Intra-articular fractures of the medial half of the mandibular condyle occur most commonly. Although unilateral injuries are more frequent, high-rise trauma tends to present with bilateral lesions. Further studies with a larger sample size should be performed to better understand TMJ patterns of injury and how they relate to possible causes.

Research on skull trauma biomechanical stress distribution in case of dental implants existence

BACKGROUND: When the jaw bone is subjected to an external force, the stress is transmitted from the force point along the alveolar bone to the skull and skull base. In the case of a dental implant, the stress distribution is mainly dependent on the implant position, type, and mechanical properties. OBJECTIVE: To investigate the dental implant position influence on the stress distribution and transmission in case of facial frontal trauma. Furthermore, the correlation between facial trauma and skull trauma in the case of a dental implant exists. METHODS: In this study, a Finite Element Method (FEM) model was constructed based on a real skull shape, size, and anatomy. Dental implants were modeled based on imported CAD Data. Five cases were investigated including no dental implant and the replacement of teeth no. 18, 19 20 and 21. Facial trauma was mimicked by applying an external load on the lower frontal jaw. Finally, the stress distribution based on the bone geometry and implant position were evaluated and compared. RESULTS: Results suggested that a dental implant could significantly influence the stress distribution in the skull in case of facial trauma. In addition, the dental position greatly affects stress transmission from the mandible to the skull bones through the zygomatic arch. CONCLUSION: The position of the dental implant could have a significant role in stress transmission and distribution in case of facial or even brain trauma. Thus, increasing the possibility of a correlation between facial and brain trauma.

Combined Deep Learning Techniques for Mandibular Fracture Diagnosis Assistance

Mandibular fractures are the most common fractures in dentistry. Since diagnosing a mandibular fracture is difficult when only panoramic radiographic images are used, most doctors use cone beam computed tomography (CBCT) to identify the patient's fracture location. In this study, considering the diagnosis of mandibular fractures using the combined deep learning technique, YOLO and U-Net were used as auxiliary diagnostic methods to detect the location of mandibular fractures based on panoramic images without CBCT. In a previous study, mandibular fracture diagnosis was performed using YOLO learning; in the detection performance result of the YOLOv4-based mandibular fracture diagnosis module, the precision score was approximately 97%, indicating that there was almost no misdiagnosis. In particular, fractures in the symphysis, body, angle, and ramus tend to be distributed in the middle of the mandible. Owing to the irregular fracture types and overlapping location information, the recall score was approximately 79%, which increased the detection of undiagnosed fractures. In many cases, fractures that are clearly visible to the human eye cannot be grasped. To overcome these shortcomings, the number of undiagnosed fractures can be reduced using a combination of the U-Net and YOLOv4 learning modules. U-Net is advantageous for the segmentation of fractures spread over a wide area because it performs semantic segmentation. Consequently, the undiagnosed case in the middle of the mandible, where YOLO was weak, was somewhat supplemented by the U-Net module. The precision score of the combined module was 95%, similar to that of the previous method, and the recall score improved to 87%, as the number of undiagnosed cases was reduced. Through this study, the performance of a deep learning method that can be used for the diagnosis of the mandibular bone has been improved, and it is anticipated that as an auxiliary diagnostic inspection device, it will assist dentists in making diagnoses.

Mandibular Ramus Fractures: A Case Series of Diversity in Rarity

Mandibular ramus fracture is usually minimally displaced as it is surrounded by the medial pterygoid medially, masseter laterally, and the pterygomasseteric sling inferiorly. They are commonly caused either by road traffic accidents or interpersonal violence. Ramus fracture is usually seen in conjunction with other mandibular fractures and is seldom found alone. The ramus is located at the congregation of the dentate and the non-dentate parts of the mandible. Ramus fractures are generally managed by closed reduction when minimally displaced but this technique has its disadvantages like poor maintenance of oral hygiene and prolonged healing time. It can get fractured in various patterns. Owing to the presence of anatomical structures on either side of the ramus and the orientation of the fracture line, the treatment plan varies in each case to prevent paresthesia by preserving the inferior alveolar nerve. This article has demonstrated four distinct kinds of mandibular ramus fractures and their management with open reduction internal fixation (ORIF).

Functional Rehabilitation after Mandibular Fracture - A Systematic Review

Background

The objective of this study was to evaluate the efficiency of functional rehabilitation in terms of mouth opening, quality of life, healing process, occlusion and dysfunction, between different treatment methods, after condylar fractures, based on the current literature.

Methods

Using the PRISMA guidelines in search of clinical trials published between 2011 and 2021, a literature analysis was performed. This search was conducted using the following Medical Subject Headings (MeSH) terms: rehabilitation OR mouth opening recovery OR function recovery AND mandibular fracture OR condylar fracture.

Results

The literature search resulted in a total of 110 study articles, of which seven publications were used in the present review, according to a selection based on the pre-established eligibility criteria. The review showed that open reduction resulted in a better three-dimensional recovery of mandibular movements and revealed greater results regarding the absence of the symptoms after applied treatment. However, studies assessing closed reduction, especially performed with intermaxillary fixation screws (IMFS), revealed excellent results in terms of quality of life, mouth opening and occlusal parameters.

Discussion

This systematic literature review showed that open reduction resulted in a better three-dimensional recovery of mandibular movements and showed greater results regarding the absence of symptoms. However, studies assessing CR, especially those performed with IMFS, revealed excellent results in terms of quality of life, mouth opening and occlusal parameters.

Customizable interdental splinting for repair of pediatric mandibular fractures in children with mixed dentition: A novel technique

OBJECTIVE

Repair of pediatric mandibular fractures (PMFs) can be challenging due to the lack of permanent dentition for immobilization, and the presence of unerupted teeth and growth plates in the mandible limiting the space for fixation. Interdental splinting (IDS) has been advocated to provide temporary fixation without the need for mandibular plating; however, there is sparse description of the surgical methodology, and data on long term outcomes are even more limited. The aim of this study is to present our technique and outcomes using a novel technique for IDS repair of pediatric mandible fractures.

STUDY DESIGN

Observational retrospective chart review.

SETTING

Tertiary care pediatric hospital.

SUBJECTS AND METHODS

Pediatric patients requiring operative repair for mandibular fracture at our tertiary care institution between 2004 and 2021 were included. Patients over 18 years of age, those who died due to associated injuries, or those who underwent non-IDS repairs were excluded. Subjects with at least 3 months of follow-up were assessed for efficacy of surgical repair and short-term adverse outcomes, and at least 1 year for long-term adverse events. Descriptive statistics were obtained.

RESULTS

Twenty-three children were included in the study with an average age of 7.4 years (range 2-17 years). Fifty-two percent (52.2%) were female. The most common fracture site was the condyle, occurring in 16 children (70%). The indication for operative repair in all cases was malocclusion. The average duration of maxillomandibular fixation (MMF) with the novel IDS was 21 days (range 12-42 days). The average length of follow up was 1.6 years (range 3 months-11 years). All children had restored, functional occlusion at follow up with none requiring further orthodontic or dental intervention. Three children of the total cohort (13.0%) had prolonged hospitalization beyond 48 h for poor oral intake. Five children (21.7%) experienced minor long-term complications including persistent temporomandibular joint pain (n = 1, 4.3%), infection (n = 2, 8.7%), hypertrophic scar (n = 1, 4.3%) and exposure of hardware (n = 1, 4.3%).

CONCLUSION

PMFs resulting in malocclusion are safely and effectively managed with operative repair utilizing a customizable IDS, with few observed short- and long-term complications.

Techniques, Tricks, and Stratagems of Oral Cavity Computed Tomography and Magnetic Resonance Imaging

The oral cavity constitutes a complex anatomical area that can be affected by many developmental, inflammatory, and tumoural diseases. MultiSlice Computed Tomography (MSCT) and Magnetic Resonance Imaging (MRI) currently represent the essential and complementary imaging techniques for detecting oral cavity abnormalities. Advanced MRI with diffusion-weighted imaging (DWI) and dynamic contrast-enhanced perfusion-weighted imaging (DCE-PWI) has recently increased the ability to characterise oral lesions and distinguish disease recurrences from post therapy changes. The analysis of the oral cavity area via imaging techniques is also complicated both by mutual close appositions of different mucosal surfaces and metal artifacts from dental materials. Nevertheless, an exact identification of oral lesions is made possible thanks to dynamic manoeuvres and specific stratagems applicable on MSCT and MRI acquisitions. This study summarises the currently available imaging techniques for oral diseases, with particular attention to the role of DWI, DCE-PWI, and dynamic manoeuvres. We also propose MSCT and MRI acquisition protocols for an accurate study of the oral cavity area.

The Influence of the Mandibular Chin Angle on the Occurrence of Mandibular Condylar Fracture: A Retrospective Study

Background

Condylar fractures are commonly associated with symphysis/parasymphysis fractures. Condylar fractures have been attributed to direct and indirect traumatic forces, the direction and magnitude of the forces, and the condylar anatomy. The chief aim of this study was to determine the association between the newly defined mandibular chin angle and the occurrence of condylar fractures.

Materials and Methods

A retrospective study was conducted to analyze two-dimensional computed tomography (2D CT) scans of patients with a history of chin trauma. The outcome was a symphysis/parasymphysis fracture with or without fracture of the mandibular condyle. The Mediff InstaRISPACS web-based platform was used to measure the chin angle. The cerebral aqueduct of Sylvius in the corresponding 2D CT midsagittal image was the standard reference plane to measure the chin angle. The SPSS Version 20 (IBM Corp, Armonk, NY) was used for data analysis.

Results

The sample size included 120 2D CT scans of patients with symphysis/parasymphysis fractures (60 associated with condylar fractures and 60 without condylar fractures). The mean chin angle in the group without condylar fracture was 133.35 ± 3.87°, which was approximately 15° lesser than in the condylar fracture group (mean, 148.56 ± 5.49°), and these findings were statistically significant (P < 0.05).

Conclusion

Individuals with a high chin angle are potentially at a higher risk of sustaining associated condylar fractures.

Automatic Detection of Mandibular Fractures in Panoramic Radiographs Using Deep Learning

Mandibular fracture is one of the most frequent injuries in oral and maxillo-facial surgery. Radiologists diagnose mandibular fractures using panoramic radiography and cone-beam computed tomography (CBCT). Panoramic radiography is a conventional imaging modality, which is less complicated than CBCT. This paper proposes the diagnosis method of mandibular fractures in a panoramic radiograph based on a deep learning system without the intervention of radiologists. The deep learning system used has a one-stage detection called you only look once (YOLO). To improve detection accuracy, panoramic radiographs as input images are augmented using gamma modulation, multi-bounding boxes, single-scale luminance adaptation transform, and multi-scale luminance adaptation transform methods. Our results showed better detection performance than the conventional method using YOLO-based deep learning. Hence, it will be helpful for radiologists to double-check the diagnosis of mandibular fractures.

Performance of deep learning models constructed using panoramic radiographs from two hospitals to diagnose fractures of the mandibular condyle

OBJECTIVE

The present study aimed to verify the classification performance of deep learning (DL) models for diagnosing fractures of the mandibular condyle on panoramic radiographs using data sets from two hospitals and to compare their internal and external validities.

METHODS

Panoramic radiographs of 100 condyles with and without fractures were collected from two hospitals and a fivefold cross-validation method was employed to construct and evaluate the DL models. The internal and external validities of classification performance were evaluated as accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC).

RESULTS

For internal validity, high classification performance was obtained, with AUC values of >0.85. Conversely, external validity for the data sets from the two hospitals exhibited low performance. Using combined data sets from both hospitals, the DL model exhibited high performance, which was slightly superior or equal to that of the internal validity but without a statistically significant difference.

CONCLUSION

The constructed DL model can be clinically employed for diagnosing fractures of the mandibular condyle using panoramic radiographs. However, the domain shift phenomenon should be considered when generalizing DL systems.