Innovative principle of implant-oriented fibula placement in mandibular reconstruction using double-barrel fibula and simultaneous implants: A technical note.

Simultaneous or secondary inserted implants with double-barrel fibula to reconstruct the mandible have become a common method. However, difficulties in later restoration caused by placement errors of fibula or incipiently placed implants have also been reported in some studies. This note describes a novel technique of implant-oriented guide plates helpful for mandible ablation, fibula segmentation and positioning, and implant placement. We design a series of guide plates especially an implant-fibula placing guide plate, and record and fix the relative spatial positions of the remaining teeth, the simultaneous implants and upper fibula. During surgery, the placement of upper fibula is oriented towards appropriate placement of implants. Therefore, the position of upper fibula can meet the requirements of simultaneous implant as much as possible. Within the limits of present observation, we believe that this technique may increase the manipuility while reducing the errors and the risk of complications.

Vascularized fascial flap for reconstruction of combined oral mucosa-mandibular defects: The multi-modal biological assessment.

OBJECTIVE: The reconstruction of composite defects in the oral and maxillofacial region using vascularized fascial flaps, such as the fibular, iliac, and temporal fascial flaps, has gained increasing attention among surgeons. However, there remains uncertainty regarding the suitability of fascial flaps as transplants, as well as their healing processes and outcomes, due to their non-mucosal nature. This study aims to comprehensively assess the biological aspects of vascularized fascial flaps at clinical, histological, and genetic levels, with the goal of providing essential biological references for their clinical application. STUDY DESIGN: This study enrolled three patients who underwent reconstruction of combined oral mucosa-mandibular defects using fibular vascularized fascial flaps between 2020 and 2023. Data regarding changes in the appearance of the fascial flaps, bulk-RNA sequencing, and histological slices of initial fascia, initial gingiva, and transformed fascia were collected and analyzed. RESULTS: Within three months, the fascial flaps exhibited rapid epithelial coverage and displayed distinct characteristics resembling mucosa. High-throughput RNA sequencing analyses and histological slices revealed that the transformed fascia exhibited tissue structures similar to mucosa and demonstrated unique advantages in promoting blood vessel formation and reducing scarring through the high-level expression of relevant genes. CONCLUSION: These findings emphasize the potential and feasibility of utilizing vascularized fascial flaps for oral mucosa reconstruction, establishing their unique advantage as transplant materials, and providing significant biological information and references for their selection and clinical application.

Carcinosarcoma of the deep lobe of the parotid gland in the parapharyngeal region: A case report.

BACKGROUND: Salivary carcinosarcoma is an extremely rare tumor containing both malignant epithelial and mesenchymal constituents. This article reports a rare case of carcinosarcoma with salivary duct carcinoma and osteosarcoma as the tumor components. The clinicopathological characteristics, treatment, and prognosis are discussed in conjunction with the literature. CASE SUMMARY: A 48-year-old man presented with a complaint of a mass in the right parotid region. Osteosarcoma was first considered for assessment by fine-needle aspiration cytology. Physical examination revealed a mass measuring approximately 4 cm × 3.5 cm × 3 cm. The mass, the whole lobe of the right parotid gland, and the right mandible were completely removed during surgery. Postoperative histopathology confirmed carcinosarcoma of the salivary gland. CONCLUSION: A definite diagnosis of salivary gland carcinosarcoma can only be obtained after complete surgical resection.

MiR-17-92 cluster regulates cell proliferation and collagen synthesis by targeting TGFB pathway in mouse palatal mesenchymal cells.

Elongation and elevation of palatal shelves, mainly caused by proliferation and extra-cellular matrix synthesis of palatal mesenchymal cells (PMCs), are essential for normal palatal development. Transforming growth factor beta (TGFB) pathway could induce proliferation inhibition and collagen synthesis in PMCs. Recent studies found that miRNA-17-92 (miR-17-92) cluster, including miR-17, miR-18a, miR-19a, miR-20a, miR-19b, and miR-92a, expressed in the 1st bronchial arch of mouse embryos during the period of palatal shelf elongation and elevation, and directly targeted TGFB pathway in cancer cell lines. Whether miR-17-92 cluster expresses and targets TGFB pathway in PMCs has not yet been studied. Using quantitative real-time RT-PCR, we found that miR-17-92 expressed in PMCs and decreased from embryonic day (E) 12 to E14 in palatal shelves. MTT assay and Western blot showed that miR-17-92 inhibited TGFB1 induced proliferation inhibition and collagen synthesis in PMCs by decreasing TGFBR2, SMAD2, and SMAD4 protein level. Further luciferase assay showed that miR-17 and miR-20a directly targeted 3'UTR of TGFBR2, and that miR-18a directly targeted 3'UTR of SMAD2 and SMAD4. We thus conclude that miR-17-92 cluster could inhibit TGFB pathway induced proliferation inhibition and collagen synthesis in PMCs by directly targeting TGFBR2, SMAD2, and SMAD4.

Maxillofacial injuries caused by the 2008 Wenchuan earthquake in China.

PURPOSE: To describe the pattern of maxillofacial injuries sustained by survivors of the 2008 Wenchuan earthquake in the West China Hospital of Stomatology from May 12 to June 23, 2008. PATIENTS AND METHODS: Cross-sectional data were analyzed using hospital-based records of earthquake survivors admitted to the West China Hospital of Stomatology. A self-designed form to record information about variables such as the gender and age of the survivors and type of location of soft and hard tissue injuries was used. RESULTS: The age of earthquake survivors of maxillofacial injuries ranged from 4 to 84 years. Fractures and soft tissue injuries were the most common of all injuries in the maxillofacial region, constituting 40.7% and 38.9%, respectively. Thirteen patients (11.5%) had dental injuries and 9 (8.0%) also had other organ injuries. CONCLUSION: During the Wenchuan earthquake, the incidence of maxillofacial injuries in survivors was relatively low compared with injury in other organs. However, because most injuries were maxillofacial fractures and facial soft tissue damage, special attention was paid to maxillofacial injury when planning and providing emergency treatment. The effective management of earthquake injuries and those caused by other types of disaster requires a multidisciplinary approach, and maxillofacial surgeons should form an integral part of this multidisciplinary team.

An E2F1/MiR-17-92 Negative Feedback Loop mediates proliferation of Mouse Palatal Mesenchymal Cells.

Normal cell cycle progression and proliferation of palatal mesenchymal cells are important for palatal development. As targets of miR-17-92, E2F transcription factors family has been suggested to induce the transcription of miR-17-92 in several cell types. In the present study, we sought to investigate whether this negative feedback loop exists in mouse PMCs and what the function of this negative feedback loop would be in palatal mesenchymal cells. Using GeneMANIA, we revealed that the most important function of experimentally verified targets of miR-17-92 is cell cycle regulation. E2F1 and E2F3, but not E2F2, were extensively expressed in mouse palate. Over-expression of E2F1 significantly increased the expression of all the members of miR-17-92. After increased by E2F1, miR-17 and miR-20a may negatively target E2F1, and thereby prevent the cells from excessive proliferation. We suggest that the negative feedback loop between E2F1 and miR-17-92 may contribute to palatal development by regulating the proliferation and cell cycle of palatal mesenchymal cells.

Regulation of plasminogen activator activity and expression by cyclic mechanical stress in rat mandibular condylar chondrocytes.

To investigate the mechanism of cartilage degradation induced by overloading in the temporomandibular joint (TMJ), the effect of cyclic mechanical compressive stress on the activity of plasminogen activator (PA) and the expression of the predominant components of the PA system were analyzed in cultured mandibular condylar chondrocytes (MCCs) in rats. MCCs were exposed to cyclic mechanical compressive stress (2000, 4000 and 6000 µ strain) at 0.5 Hz by a four­point bending system. The activity of PA was determined by hydrolysis of the chromogenic substrate H­D-Val-Leu-Lys­pNA (S­2251). The mRNA and protein expression levels of urokinase­type PA (uPA), tissue­type PA (tPA), uPA receptor (uPAR) and PA inhibitor 1 (PAI­1) were detected by qPCR and western blot analysis, respectively. Cyclic mechanical stress at 4000 and 6000 µ strain induced the expression of uPA, tPA and uPAR, and increased the activity of PA. Furthermore, cyclic mechanical stress at 6000 µ strain also inhibited the expression of PAI­1. Analysis of pericellular proteolytic activity demonstrated that PA functioned as the active enzyme in excessive mechanical stress responsiveness (e.g., 4000 and 6000 µ strain) largely via uPAR, not PAI­1. Cyclic mechanical stress at 2000 µ strain induced the expression of tPA and PAI­1; however, it did not change the activity of PA. These results suggested that the mechanical induction of uPA, tPA and uPAR upregulated PA activity, which may provide a proteolytic environment of extracellular matrix components and subsequently contribute to the cartilage degradation in TMJ osteoarthritis.

Maxillofacial space infection experience in West China: a retrospective study of 212 cases.

OBJECTIVES: Our objectives were to analyze the clinical features of maxillofacial space infection (MSI) patients admitted to the West China Hospital of Stomatology over a five-year period, and to identify potential risk factors associated with life-threatening complications. METHODS: A retrospective medical chart review was performed and the sociodemographic and clinical characteristics of patients with MSI were evaluated. RESULTS: A total of 212 patients were enrolled in this study, including 125 males (59.0%) and 87 females (41.0%), with an age range of 1-88 years (median 47.5 years). The most common cause of MSI was odontogenic infection (56.1%). The submandibular space was the space most commonly involved in both single space and multiple space infections (37.5% and 29.1%, respectively). One hundred and two patients (48.1%) self-medicated before admission, and the time from onset of symptoms until presentation was longer in those who self-medicated compared with those who did not (p=0.028). Fifty-seven patients (26.9%) had life-threatening complications and six died (2.8%). In multivariate analysis, age, self-medication, admission temperature, respiratory difficulty, and underlying diseases were found to be risk factors for life-threatening complications. The most common occupation of the patients was farmer (54.7%). Among the farmers, 72.4% had an odontogenic etiology; however, 91.7% of the farmers with odontogenic space infections had not undergone dental treatment before admission. CONCLUSIONS: Our experience suggests that the management of MSI should be more aggressive when the above risk factors are present, in order to avoid life-threatening complications. In addition, considering the poor medical conditions in the rural areas of West China, standard dental care and services should be provided in the future to replace self-medication.

Analysis of 46 maxillofacial fracture victims in the 2008 Wenchuan, China earthquake.

PURPOSE: At 14:28 hours on May 12, 2008, a massive earthquake wracked most areas of Sichuan, China, causing catastrophic human loss. The aim of this study was to delineate the characteristics of victims with maxillofacial fractures in this disaster. PATIENTS AND METHODS: A descriptive analysis was conducted based on the medical records of earthquake maxillofacial injuries casualties transferred to West China Hospital of Stomatology, Sichuan University, after the earthquake. Data regarding demographic details, psychological status, patterns, anatomic sites, etiology, concomitant injuries, and management of earthquake maxillofacial fractures were evaluated. RESULTS: A total of 46 maxillofacial fracture patients' records of 28 (60.9%) males and 18 (39.1%) females were included in this study, with peak incidence (32.6%) in the elderly age group (older than 50 years). The most common etiology of earthquake maxillofacial fractures was building collapse (71.7%). The mandible (65.2%) was the most frequent site of the maxillofacial fracture, followed by the zygomatic complex (21.7%) and maxilla (13.0%). The most prevalent of maxillofacial fracture pattern was multiple and/or comminuted fractures (56.5%), which accounted for 72.7% (24/33) in building collapse injury group. There were 9 (19.6%) patients with significant concomitant injuries and the most common site of concomitant injuries was the head (4 cases) and extremity (4 cases). Four (8.7%) patients' maxillofacial fractures were treated conservatively, 16 (34.8%) underwent closed reduction and fixation, and 26 (56.5%) underwent open reduction and rigid internal fixation (RIF). Apart from 3 patients (6.5%) who showed infection, all patients with facial fractures achieved successful bony union with an acceptable occlusion and facial form. Additionally, it is noteworthy that all patients in our study presented the symptoms of posttraumatic stress disorder (PTSD). CONCLUSION: There is a variation of mechanism of injuries, age group, severity, patterns, concomitant injuries, and management of earthquake maxillofacial fractures. Knowledge of these characteristics provides useful strategies for patient care and prevention of further complications. A multidisciplinary and coordinated approach is important for optimum stabilization and ongoing treatment of victims of building collapse injury. The high percentage of PTSD confirms that psychologists should form an integral part of this multidisciplinary team.