[In vitro biological evaluation of PEGylated poly(glycerol sebacate)/ß-TCP-coating modified magnesium alloy].

PURPOSE: To prepare PEGS/ß-TCP modified magnesium alloy (PEGS/ß-TCP/MZG) membranes by forming a glycolated poly(sebacate)/ß-tricalcium phosphate (PEGS/ß-TCP) coating on the surface of magnesium-zinc-gadolinium alloy (MZG) membranes, and to evaluate the osteogenic induction activity and immunomodulatory properties of PEGS/ß-TCP/MZG using the material extract medium. METHODS: PEGS/ß-TCP coating was prepared on the surface of MZG by solvent method, and the PEGS/ß-TCP/MZG membrane was fabricated and compared with PEGS/ß-TCP and MZG to examine the morphology, composition, and hydrophilicity. The amount of magnesium ions released and the pH value of the materials were tested after 3 days of immersion. The cell viability and osteogenic differentiation of MC3T3 cells induced by extract medium were investigated by CCK-8 assay, ALP and mineralized nodule staining. The cell viability and polarization of RAW cells induced by extract medium were then investigated. The expression of macrophage-secreted cytokines was examined by PCR analysis. GraphPad Prism 9.0 software package was used for statistical analysis. RESULTS: PEGS/ß-TCP/MZG membranes with PEGS/ß-TCP coating tightly embedded with MZG were successfully fabricated, and the material had good hydrophilicity. The results of degradation experiments indicated that the PEGS/ß-TCP coating effectively slowed down the degradation rate of MZG, leading to a lower pH value and concentration of Mg2+ ion in the extract medium of PEGS/ß-TCP/MZG group. The results of in vitro cell experiments showed that PEGS/ß-TCP/MZG had no significant effect on the proliferation activity of both MC3T3-E1 and macrophages. PEGS/ß-TCP/MZG significantly enhanced the expression of ALP and mineralized nodule staining in MC3T3-E1. Although there was no significant difference in macrophage polarization pattern between PEGS/ß-TCP and PEGS/ß-TCP/MZG groups, PEGS/ß-TCP/MZG further reduced inflammation based on the immunomodulation of PEGS/ß-TCP coating related TNF-α expression and increased osteogenesis related TGF-ß expression. CONCLUSIONS: MZG membrane modified by PEGS/ß-TCP may provide a new material option for the development of bone tissue engineering.

[Temporal and spatial expression of Swell1 gene in the development of mouse condyle cartilage].

PURPOSE: To explore the temporal and spatial expression pattern of Swell1 (LRRC8A) gene in mouse condylar cartilage. METHODS: By obtaining condyle samples of embryos at 15.5, 16.5, 18.5 days and newborn mice, H-E staining, immunofluorescence staining and qRT-PCR were used to explore the microstructure of mouse condyles and the temporal and spatial expression changes of genes related to cartilage development and Swell1 gene. Statistical analysis was performed using SPSS 25.0 software package. RESULTS: Swell1 gene expression began in the hypertrophic chondrocyte layer during the development of the condyle from embryonic day 16.5, and then gradually increased, and continued to be expressed during mouse embryonic development until the mouse was born. CONCLUSIONS: Swell1 is mainly expressed in hypertrophic chondrocytes during the development of mouse condyles, and it may be involved in the regulation of chondrocyte hypertrophy.

Expert Consensus on Procedures and Operations of Navigation-guided Needle Biopsy Techniques for Skull Base Tumours.

Skull base surgery is an interdisciplinary subject. The anatomical structures in the skull base related to oral and maxillofacial surgery include the parapharyngeal space, the pterygopalatine fossa and the infratemporal space. This operative area is one of the most challenging surgical areas in oral and maxillofacial surgery due to its deep site, complex anatomy and high risk. Obtaining pathological information of the tumour preoperatively may help surgeons optimise their treatment plan. Needle biopsy is one of the major minimally invasive techniques that allows preoperative pathological results to be obtained. The navigation technology, which is developing rapidly nowadays, provides a reliable assistance for deep tissue biopsy surgery. Experts from the Society of Oral and Maxillofacial Surgery, Chinese Stomatological Association formulated an expert consensus on the procedures and operations of navigation-guided needle biopsy techniques for skull base tumours, so as to standardise and promote the application and operation of navigation-guided needle biopsy for skull base tumours.

Expert Consensus for the Treatment Algorithm for Navigationassisted Reconstruction of Maxillofacial Deformities.

Deformities of the maxillofacial region following trauma and ablative surgery are devastating and not uncommon. Reconstruction of such defects is a surgically challenging procedure. Conventionally, reconstruction of dental arch defects lacks preoperative customised planning and relies heavily on the surgeon experience to ensure optimum surgical outcomes. The restoration of the dental arch shape and function has taken precedence after an extensive tumour resection surgery, especially in the current age of technological advancement. Thus, personalised and accurate reconstruction of dental arch defects has become a new goal. Computer-assisted surgery, especially navigation-assisted surgery, has gained popularity of late, in reconstructing deformities and restoring facial symmetry, appearance and function in the maxillofacial region. This technology provides a clearer three-dimensional visualisation of the area of interest and its relationship with the adjacent vital structures. Together with preoperative virtual surgical planning, it allows more specific and accurate osteotomies, thus reducing the ischemia and total operating times substantially. The risk of complications is also minimised whilst improving the final surgical outcomes. The use of the intraoperative navigation system and other computer-assisted surgical techniques during surgery can significantly improve the precision of the reconstruction of dental arch deformities, and achieve personalised and functional reconstructive goals while enhancing the quality of life of patients postoperatively. The Society of Oral and Maxillofacial Surgery, Chinese Stomatological Association provides the present professional perspective and treatment protocol for navigation-guided reconstruction of dental arch defects, to allow standardisation of the technique while promoting its application among oral and maxillofacial surgeons.

Expert Consensus on Navigation-guided Unilateral Delayed Zygomatic Fracture Reconstruction Techniques.

The zygoma is located in the medial and lateral parts of the face, supporting the midfacial contour. The forward projection of the zygoma and the zygomatic arch often expose them to injury. Fractures of the zygoma can lead to the displacement of the zygoma and the zygomatic arch, causing facial collapse deformity. For delayed zygomatic fractures, the loss of normal anatomical landmarks caused by the malunion of the fracture lines and remodelling of the bony contour makes it difficult to determine the correct positions of the zygomatic bones. In such cases, ideal and steady outcomes with satisfactory midface symmetry have been difficult to obtain using traditional surgical methods. Nowadays, the application of digital surgical software and surgical navigation helps surgeons to perform accurate preoperative simulations to obtain ideal three-dimensional virtual surgical plans and achieve accurate reduction by intraoperative navigation systems, which increase the accuracy and predictability of fracture reduction outcomes. Experts from the Society of Oral and Maxillofacial Surgery, Chinese Stomatological Association have fully discussed and formulated an expert consensus on navigation-guided unilateral delayed zygomatic fracture reconstruction techniques to standardise the clinical operation procedures and promote the application.

Expert Consensus on Navigation-guided Unilateral Orbital Fracture and Orbital Floor Reconstruction Techniques.

Orbital fracture and orbital floor reconstruction surgery is characterised by limited surgical exposure and high risks. Before the advent of digital technology, the design and implementation of the surgical scheme for orbital floor reconstruction surgery mainly depended on the intuitive understanding of imaging and the clinical experience of surgeons, with strong unpredictability and experience dependence. Surgical navigation systems with real-time positioning and imaging functions, when used in orbital reconstruction surgery, can detect the real-time intraoperative position, avoid risks, and assist in locating the reconstruction position to ensure the accuracy of orbital reconstruction, with the help of a preoperative surgical plan. Many studies have confirmed its effect. Unilateral orbital fracture and orbital floor reconstruction surgery is one of the earliest and most widely used surgical techniques in maxillofacial surgery. Experts from the Society of Oral and Maxillofacial Surgery, Chinese Stomatological Association have fully discussed and formulated this expert consensus on navigation-guided unilateral orbital fracture and orbital floor reconstruction techniques to standardise the clinical surgical procedures and promote its application.

[The effect of Foxc2 overexpression on the osteogenic properties of C3H10T1/2 cells].

PURPOSE: To investigate the effect of Foxc2 overexpression on osteogenic and adipogenic differentiation of C3H10T1/2 cells. METHODS: C3H10T1/2 cells were transfected with plenti-Foxc2 and selected with puromycin for stable clones. The expression of Foxc2 was determined by real-time PCR and Western blot. Cell proliferation was detected by CCK-8 kit. Cell cycle and apoptosis were detected by flow cytometry. The level of osteogenic biomarkers Runx2, OPN, OCN and adipogenic biomarker PPARγ were quantified by real-time PCR and Western blot. Alkaline phosphatase (ALP) staining and oil red staining were conducted to evaluate the effect of Foxc2 overexpression on osteogenic and adipogenic differentiation. Statistical analysis was performed using SPSS 17.0 software package. RESULTS: C3H10T1/2-Foxc2 cell line was successfully constructed and verified by direct sequencing and Foxc2 overexpression in vitro. Cell proliferation was reduced and cell cycle was blocked in G1/G0 phase. Enhanced ALP staining and reduced oil red staining were observed in C3H10T1/2-Foxc2 cells as compared with the control. Foxc2 overexpression up-regulated Runx2, OPN, OCN during osteogenic differentiation and down-regulated PPARγduring adipogenic differentiation. CONCLUSIONS: C3H10T1/2 cell line stably expressing Foxc2 gene was successfully established, cell proliferation was reduced, osteogenesis biomarkers were up-regulated during the osteogenesis by overexpression Foxc2, PPARγwas down-regulated during adipogenesis.

Hepatic Premalignant Alterations Triggered by Human Nephrotoxin Aristolochic Acid I in Canines.

Aristolochic acid I (AAI) existing in plant drugs from Aristolochia species is an environmental human carcinogen associated with urothelial cancer. Although gene association network analysis demonstrated gene expression profile changes in the liver of human TP53 knock-in mice after acute AAI exposure, to date, whether AAI causes hepatic tumorigenesis is still not confirmed. Here, we show that hepatic premalignant alterations appeared in canines after a 10-day AAI oral administration (3 mg/kg/day). We observed c-Myc oncoprotein and oncofetal RNA-binding protein Lin28B overexpressions accompanied by cancer progenitor-like cell formation in the liver by AAI exposure. Meanwhile, we found that forkhead box O1 (FOXO1) was robustly phosphorylated, thereby shuttling into the cytoplasm of hepatocytes. Furthermore, utilizing microarray and qRT-PCR analysis, we confirmed that microRNA expression significantly dysregulated in the liver treated with AAI. Among them, we particularly focused on the members in let-7 miRNAs and miR-23a clusters, the downstream of c-Myc and IL6 receptor (IL6R) signaling pathway linking the premalignant alteration. Strikingly, when IL6 was added in vitro, IL6R/NF-κB signaling activation contributed to the increase of FOXO1 phosphorylation by the let-7b inhibitor. Therefore, it highlights the new insight into the interplay of the network in hepatic tumorigenesis by AAI exposure, and also suggests that anti-premalignant therapy may be crucial for preventing AAI-induced hepatocarcinogenesis.

[Study of the influence of nodal liquefaction in measurement of the ADC value of OSCC metastatic lymph nodes in patients with oral squamous cell carcinoma].

PURPOSE: To study the influence of nodal liquefaction portion in the measurement of the ADC value of metastatic lymph nodes in patients with oral squamous cell carcinoma (OSCC) on DW-MRI images. METHODS: According to the postoperative histopathological examination results, the DW-MRI data of 25 OSCC patients was analyzed. The ADC values of both solid portions of metastatic lymph nodes and the whole metastatic lymph nodes with internal liquefaction were selected and measured. Further comparison between the 2 groups was processed for 2 independent samples t test with SPSS 17.0 software package. RESULTS: Eleven patients out of all cases were diagnosed with cervical lymph node metastasis, and 15 metastatic lymph nodes were detected, among which 8 metastatic lymph nodes had obvious internal liquefaction. The average ADC values of solid portions of metastatic lymph nodes (group SMLN) and the whole metastatic lymph nodes with internal liquefaction (LMLN group) ADC were (872.1 ± 22.65) × 10⁻6 mm²/s (n=15) and (1073 ± 16.99) × 10⁻6 mm²/s (n=8), respectively. Two independent samples t test showed statistically significant difference of ADC values between group SMLN and group LMLN (P<0.05). CONCLUSIONS: The internal liquefaction in OSCC metastatic lymph nodes can lead to an increased average ADC value. If the measurement of OSCC metastatic lymph nodes includes obvious liquefaction portions, it may reduce the diagnostic accuracy of DW-MRI for discrimination of lymph node metastasis.

[Evaluation of flipped classroom teaching model in undergraduates education of oral and maxillofacial surgery].

Flipped classroom is a new teaching model which is different from the traditional teaching method. The history and characteristics of flipped classroom teaching model were introduced in this paper. A discussion on how to establish flipped classroom teaching protocol in oral and maxillofacial surgery education was carried out. Curriculum transformation, construction of education model and possible challenges were analyzed and discussed.

[GSTP1 Ile105Val polymorphism confer susceptibility to oral cancer:a meta-analysis].

PURPOSE: This meta-analysis was aimed to evaluate the association of glutathione S-transferase P1 (GSTP1) Ile105Val genetic polymorphism with susceptibility to oral cancer. METHODS: A literature search of PubMed, Chinese BioMedical, Wanfang, VIP, CNKI databases was conducted from inception to July 15th, 2013. Crude odd ration (OR) with 95% confidence intervals (CI) was calculated. RESULTS: Thirteen case-control studies were assessed, including 2,019 oral cancer patients and 3,282 healthy controls. Meta-analysis showed that the overall association between GSTP1 Ile105Val polymorphism and susceptibility to oral cancer was not significant. However, further stratified analyses based on ethnicity indicated that this association was significant in East Asians (Val vs. Ile: OR=1.42, 95%CI: 1.06-1.90, P=0.019; Val/Val+Ile/Val vs. Ile/Ile: OR=1.59, 95%CI: 1.13-2.23, P=0.007) and Euro Caucasians (Val vs. Ile: OR=1.34, 95%CI: 1.03-1.75, P=0.032; Val/Val+Ile/Val vs. Ile/Ile: OR=1.66, 95%CI: 1.15-2.38, P=0.006), but not significant in South Asians and America Caucasians. CONCLUSIONS: This meta-analysis provides further evidence that GSTP1 Ile105Val polymorphism may be associated with oral cancer risk among East Asians and Euro Caucasians. However, further large-scale studies are needed to determine the association of GSTP1 Ile105Val genetic polymorphism with susceptibility to oral cancer.

[Inter-relationship between mandibular rotation center and maxillary Le Fort I impaction osteotomies].

PURPOSE: The purpose of the present investigation was to locate the instantaneous rotation center of the mandible during maxillary surgical impaction, and explore the relationship between automatic rotation center of the mandible and maxillary elevation amount, the length of the mandible and mandibular plane angle. METHODS: Twenty-five patients who underwent maxillary Le Fort I impaction without concomitant major mandibular ramus split osteotomies were included. The preoperative and postoperative lateral cephalograms were used to evaluate the surgical changes and locate the mandibular autorotation center with Reuleaux method. The automatic rotation center of the mandible was compared to the maxillary elevation amount, the length of the mandible and mandibular plane angle with Pearson correlation and linear regression analysis. The data was analyzed by SPSS 13.0 software package. RESULTS: The mandibular automatic rotation center was located in average 15.64 mm below and 0.82 mm behind the center of the condylar head in these 25 patients. The correlation analysis demonstrated a positive correlation between maxillary elevation amount, the length of the mandible and the position of the rotation center of the mandible. Similar positive correlation was presented between the mandibular plane angle and the vertical position of the rotation center of the mandible. CONCLUSIONS: The rotation center in 25 cases were located outside the condylar head. The maxillary elevation amount, the length of the mandible and the mandibular plane angle was positively correlated to the position of the rotation center of the mandible.

p75 neurotrophin receptor positive dental pulp stem cells: new hope for patients with neurodegenerative disease and neural injury.

Neurodegenerative diseases and neural injury are 2 of the most feared disorders that afflict humankind by leading to permanent paralysis and loss of sensation. Cell based treatment for these diseases had gained special interest in recent years. Previous studies showed that dental pulp stem cells (DPSCs) could differentiate toward functionally active neurons both in vitro and in vivo, and could promote neuranagenesis through both cell-autonomous and paracrine neuroregenerative activities. Some of these neuroregenerative activities were unique to tooth-derived stem cells and superior to bone marrow stromal cells. However, DPSCs used in most of these studies were mixed and unfractionated dental pulp cells that contain several types of cells, and most were fibroblast cells while just contain a small portion of DPSCs. Thus, there might be weaker ability of neuranagenesis and more side effects from the fibroblast cells that cannot differentiate into neural cells. p75 neurotrophin receptor (p75NTR) positive DPSCs subpopulation was derived from migrating cranial neural crest cells and had been isolated from DPSCs, which had capacity of differentiation into neurons and repairing neural system. In this article, we hypothesize that p75NTR positive DPSCs simultaneously have greater propensity for neuronal differentiation and fewer side effects from fibroblast, and in vivo transptantation of autologous p75NTR positive DPSCs is a novel method for neuranagenesis. This will bring great hope to patients with neurodegenerative disease and neural injury.

Application of lateral thoracic flap in maxillofacial defect reconstruction: experience with 28 cases.

Lateral thoracic (LT) flaps are primarily used as pedicle flaps for reconstructing limb and chest wall defects and have rarely been applied for head and neck reconstruction. We aimed to present our surgical techniques and experience using free LT cutaneous, myocutaneous and conjoint flaps for oral and maxillofacial reconstruction. From 2006 to 2010, we reconstructed 28 cases of oral and maxillofacial soft tissue defects using LT flaps. Controls were 54 cases reconstructed with anterior forearm flaps during same period. Flap size and pedicle length were recorded intraoperatively. Patients were monitored for flap survival in hospital until discharge and then followed regularly for 3-38 months, assessing for tumor recurrence, flap appearance, donor site function and cosmesis. All patients had free flaps except for one LT pedicle flap. LT flap patients were significantly younger than controls (45.5 vs. 54.8 years, p=0.004) and had greater flap size than controls (55.2 cm2 vs. 40.3 cm2, p=0.001). Of 28 LT flaps transferred, 26 survived completely; 1 failed (total necrosis due to venous insufficiency), and 1 suffered tip necrosis. No significant differences were observed in flap survival between groups. Follow-up was shorter in LT flap patients than in controls (20.3 months vs. 26.9 months, p=0.02). Application of the LT flap is a reliable technique for reconstruction of maxillofacial defects with minimal donor site morbidity and favorable aesthetic outcomes.

Computer-assisted orthognathic surgery combined with fibular osteomyocutaneous flap reconstruction to correct facial asymmetry and maxillary defects secondary to maxillectomy in childhood.

Maxillectomy in childhood not only causes composite primary defects but also secondary malformation of the middle and lower face. In the case presented, we introduced computer-assisted planning and simulation of orthognathic surgery combined with fibular osteomyocutaneous flap reconstruction to correct complex craniofacial deformities. Virtual orthognathic surgery and maxillary reconstruction surgery were undertaken preoperatively. LeFort I osteotomy, with bilateral sagittal split ramus osteotomy and lower border ostectomy, was performed to correct malocclusion and facial asymmetry. Maxillary reconstruction was accomplished using a fibular osteomyocutaneous flap. The patient recovered uneventfully with an adequate aesthetic appearance on 3D computed tomography. Our experience indicates that orthognathic surgery combined with fibular osteomyocutaneous flap reconstruction can used to correct complex facial asymmetry and maxillary defects secondary to maxillectomy. Computer-assisted simulation enables precise execution of the reconstruction. It shortens the free flap ischemia time and reduces the risks associated with microsurgery.

Current undergraduate and postgraduate dental education in China.

China is a developing country with the largest population of any country in the world. The 2010 sixth national census found that China's population was 1,339,724,852, accounting for about 19 percent of the world's total population. However, higher education in the Chinese dental field started late and developed slowly. In order to acquaint more dental educators worldwide about China's current higher dental education system, this article provides a brief introduction to the present education system, degrees conferred, curriculum setting, training mode, teaching materials, courses, and academic journals.

Bone grafting, corticotomy, and orthodontics: treatment of cleft alveolus in a chinese cohort.

Objective : A multimodal therapy was applied to solve a set of related problems including collapse of the posterior segment, high level gingival margin of canine, and resorption of grafted bone in a cohort of Chinese youngsters with cleft lip and palate. This study aimed to evaluate the benefits of this treatment procedure. Methods : Thirty patients with unilateral cleft lip and palate were included in this prospective study. All patients had previously undergone only cleft lip and palate repair and presented with alveolar cleft and an obvious step in the gingival margin between the canine tooth and the teeth beside it. A multimodal therapy that included bone grafting, corticotomy, and orthodontics was applied to solve these problems. Grafted bone volume, parallelism of the roots, root resorption, gingival margin, and mobility of the canine on the cleft side were established before surgery, 1 week after surgery, and after straightening of the canine. Results : Less than 25% of the grafted bone was reabsorbed in 25 of the 30 patients, while less than 50% was resorbed in the remaining five. The roots of the canines on the cleft side were mostly parallel to the adjacent teeth. Root resorption and mobility of the canines were slight. The difference in the gingival margin between the canines on the cleft side and the other side was small. Conclusions : Canines moved into the grafted bone safely and effectively, thus achieving a normal gingival margin and retaining grafted bone volume in one operation.

[Application of computer-assisted navigation in oral and maxillofacial surgery: retrospective analysis of 104 consecutive cases].

PURPOSE: To evaluate the application of computer-assisted navigation system (CANS) in Oral and Maxillofacial Surgery. METHODS: One hundred and four patients were included in this study, including 34 with zygomatic-orbital-maxillary fracture, 27 with unilateral TMJ ankylosis, 29 with fibrous dysplasia, 9 with mandibular angle hypertropia, 3 with cartilage and bone tumors and 2 with facial foreign bodies. CT scan was performed and the data was saved as Dicom (digital imaging and communications in medicine) format. With preoperative planning and 3-dimensional simulation, normal anatomic structures of the affected side were created by superimposing and mirroring the unaffected side. The osteotomy lines, amount and range of resection, the reduction position of bony segments and the reconstruction morphology was determined and displayed. All surgeries were performed under the guidance of navigation system. The accuracy of navigation was evaluated by comparing the postoperative CT three-dimensional model with preoperative surgical planning. RESULTS: Through registration, an accurate match between the intra-operative anatomy and the CT images was achieved. With the guidance of navigation, anatomic structures and the position of surgical instruments were shown real-time on the screen. No complications occurred in all patients and the systematic error was within 1 mm. Good coincidence with preoperative planning was achieved for osteotomy lines, the amount of resection and reduction of fractures. The mean error between virtual and real results was (1.46±0.24) mm. All patients healed uneventfully and facial symmetry was improved. CONCLUSIONS: With the ability of preoperative planning, surgical simulation and postoperative prediction, CANS shows its great value in improving the accuracy of oral and maxillofacial surgery, reducing trauma and restoring facial symmetry. It is regarded as a valuable and safe technique in this potentially complicated procedure.

[Exploration for micro-osteotomy assisted orthodontic treatment of skeletal Class III malocclusions with alveolar hypoplasia in the lower anterior region].

PURPOSE: To investigate the changes of periodontal conditions after micro-osteotomy assisted lower incisor decompensation for skeletal Class III malocclusions with alveolar hypoplasia in the lower anterior region. METHODS: The sample consisted of 22 cases diagnosed as skeletal Class III malocclusions with alveolar hypoplasia in the lower anterior region, selected from consecutive patients of Department of Oral & Cranio-maxillofacial Science of Shanghai Ninth People's Hospital during 2009-2012. The samples were divided into 2 groups; G1 comprised 10 patients who accepted micro-osteotomy assisted lower incisor decompensation; G2 comprised 12 patients who chose traditional pre-surgical decomposition. The changes of periodontal conditions of both groups were evaluated with the help of cone-beam CT(CBCT). Data was processed using SAS8.02 software package. RESULTS: For subjects in G1, during the micro-osteotomy assisted pre-surgical orthodontics, no significant difference was found in the amount of root resorption of lower incisors.But labial and lingual vertical alveolar bone loss were 2.60 mm and 2.22 mm; alveolar bone thickness increased by 3.05 mm on the labial side and decreased by 0.88 mm on the lingual side (P<0.05). Better periodontal conditions were reserved compared with those of G2. CONCLUSIONS: Micro-osteotomy assisted pre-surgical orthodontics was much safer than traditional orthodontics for skeletal Class III malocclusions with alveolar hypoplasia in the lower anterior region.