[Clinical factors affecting the prognosis of lower gingival squamous cell carcinoma].

OBJECTIVE: To define the clinical factors that influence local recurrence and survival in patients with lower gingival squamous cell carcinoma (LGSCC) and determine whether bone invasion is an independent prognostic factor for them. METHODS: A total of 104 patients with LGSCC hospitalized in Peking University Stomatology Hospital from June 2013 to December 2015 were enrolled in this retrospective study.All the patients were followed-up for more than 3 years.The degree of bone invasion was assessed using preoperative imaging data (CT and panoramic radiograph).The degree of bone invasion was divi-ded into four categories: no bone invasion, invasion of cortical bone, invasion of bone marrow cavity, and invasion of the mandibular canal.According to the central position of tumor, it was divided into two types: anterior mandibular invasion (anterior region of the mental foramen) and posterior mandibular invasion (posterior region of the mental foramen). RESULTS: of different invasion depth groups were compared using Mann-Whitney U test.P value < 0.05 was considered to be statistically significant.Kaplan-Meier survival analysis method was used to draw survival curve, and COX regression was used to explore the risk ratio (HR) and 95% confidence interval (CI) of prognostic factors of LGSCC. RESULTS: The follow-up results showed that the 1-, 3-, and 5-year survival rates of LGSCC in this group were 91%, 84%, 82%, respectively.32.7%(34/104) of patients had cervical lymph node metastasis.The cervical lymph node metastasis rate of the anterior segment of the mandible was 12.5%(2/16), and 36.4%(32/88) for the posterior segment of the mandible (P < 0.05).Univariate and multivariate COX analysis showed that the N stage and local recurrence were the prognostic factors of LGSCC patients (P < 0.05). CONCLUSION: As the degree of mandibular invasion increases, the prognosis of patients with mandibular gum cancer becomes worse.N stage and local recurrence are prognostic risk factors for LGSCC.The incidence of cervical lymph node metastasis for LGSCC is related to the primary tumor location.It is concluded that tumors located at the posterior of the mandible might be more prone to cervical lymph node metastasis than the anterior of the mandible.Thus various levels of cervical lymph node dissection strategies should be adopted for different sites of LGSCC.

[Analysis of pathological characteristics of medication-related osteonecrosis of the jaw and discussion of clinical treatment strategies based on the pathological analysis results].

OBJECTIVE: To summarize the pathological characteristics of medication-related osteonecrosis of the jaw (MRONJ) specimens after jaw curettage or jaw osteotomy treatment and to comprehensively analyze the relationship between the different pathological features, treatment methods, and treatment effects to provide new ideas for effective treatment of MRONJ in clinical work. METHODS: The clinical and pathological data were collected from 23 patients with MRONJ who were treated with curettage (18 patients) and jaw osteotomy (5 patients) at the Department of Oral and Maxillofacial Surgery of Peking University Hospital of Stomatology between June 2014 and December 2015. The pathological characteristics of MRONJ were summarized and analyzed with treatment effects based on various surgical treatment methods. The diagnostic criteria and disease staging of MRONJ were determined according to the 2014 American Association of Oral and Maxillofacial Surgeon's Position Paper. RESULTS: In this study, 5 patients have treated with jaw segmental osteotomy, and all of them were in stage Ⅲ; the other 18 patients were treated with jaw curettage, including 5 patients in stage Ⅱ and 13 patients in stage Ⅲ. The pathological features of MRONJ in five cases of jaw segmental osteotomy were divided into three adjacent regions from shallow to deep: inflammation region (IR), sclerosis region (SR), and bone remodeling layer (BRL). Moreover, three types of pathological features of specimens from traditional curettage were defined as type 1 (IR), type 2 (IR + SR), and type 3 (IR + SR + BRL). The pathological features of the patients treated with jaw curettage were: type Ⅰ, 38.9% (7/18); type Ⅱ, 44.4% (8/18); type Ⅲ, 16.7% (3/18). Complete healing was achieved in 5 patients treated with jaw segmental osteo-tomy. Moreover, 2 cases with type Ⅰ, 1 case with type Ⅱ, and 1 with type Ⅲ completely healed after jaw curettage, while 5 cases with type Ⅰ, 7 cases with type Ⅱ, and 2 cases with type Ⅲ experienced recurrence after surgery. CONCLUSION: Pathological features of continuous regions of inflammation, sclerosis, and bone remodeling layer were identified from shallow to deep, based on the microscopic observation of jaw segmental osteotomy samples. Insufficient removal of the sclerotic region during jaw curettage that blocks the required blood, nutritional factors, and mesenchymal stem cells seems to be a common cause for failed treatment of MRONJ after curettage surgery.

[Clinical analysis of selective tracheostomy necessary for patients undergoing head and neck surgery with free flap reconstruction].

OBJECTIVE: To discover the factors that may affect the use of selective tracheostomy among patients who have undergone head and neck surgeries with free flap reconstruction, so that the patients will not need tracheostomy nor receive the unnecessary treatment. METHODS: Five hundred and thirty-three patients who had undergone head and neck surgery with free flap reconstruction operated by the same team of surgery at Department of Oral and Maxillofacial Surgery at Peking University School of Stomatology from 2015 to 2016 were reviewed. Three hundred and twenty-one (60.2%) of these patients underwent selective tracheostomy. All the patients' demographic information, operation-related information, prior treatments, comorbidities and complications were recorded and analyzed. RESULTS: The patients with defects of the tongue, mouth floor, oropharynx and bilateral mandible, who underwent neck dissection and with previous radiotherapy and smoking habit were more likely to get selective tracheostomy. Usage of bulky soft tissue flap might also add to the risk of airway obstruction and the need of selective tracheostomy, while other factors were not significantly related to the risk of postoperative airway obstruction and the patients could be kept safe without selective tracheostomy. Most cases without tracheostomy were kept safe except one case, while 8.39% of the patients with tracheostomy suffered from tracheostomy related complications, mainly pneumonia and hemorrhage of the tracheostomy wound, yet none led to serious consequences or even death. CONCLUSION: Selective tracheostomy is not necessary for patients who have undergone head and neck surgeries with free flap reconstruction except that there are defects at the tongue, oropharynx and mandible. Neck dissection, bulky soft tissue flap reconstruction, previous radiotherapy and smoking habit may also add to the risk of postoperative airway obstruction, while a favorable decision would involve a combination of all the above factors to assure the safety of the postoperative airway for the patients undergone head and neck surgeries with free flap reconstruction.

[Application of iodine staining technique for tumor identification in Micro-CT of mouse model with skull base-infratemporal fossa tumor].

OBJECTIVE: To establish an animal model with malignant tumor in the skull base-infratemporal region, and to explore the role of iodine staining technique in identifying tumor tissues with Micro-CT data. METHODS: Sedation anesthesia was carried out on 12 BABL/c nude mice using inhaled isoflurane, and then WSU-HN6 cells that cultured and immortalized from human tongue squamous cell carcinoma were injected into the right infratemporal fossa via the submandibular area. The procedure was carried out under ultrasonographic guidance. The nude mice were sacrificed after 3 weeks observation. The head specimens were fixed and scanned by Micro-CT, and repeated scans were performed after staining with 3.75% compound iodine solution. Following decalcification in 20% EDTA for 2-4 weeks, the head specimens were embedded and sectioned. Hematoxylin and eosin staining and Pan-Keratin immunohistochemical staining were carried out. Bright-field microscopy and stereomicroscopy were used to visualize. The Micro-CT data were analyzed using iPlan software (Brainlab). RESULTS: Non-traumatic ultrasonography was used to guide HN-6 cells injection and confirm skull-base tumor formation in all the animals. Ultrasonographic guidance reduced the risk of cervical vessel injury when transferring tumor cells into the skull base space. An obvious asymmetrical appearance was detected via ultrasonography 3 weeks after tumor cell injection. The Micro-CT analysis showed that the bone was obviously damaged on the right side of the skull base, but the soft tissue image was unrecognizable. After four days staining with compound iodine solution, the morphology of the tumor and surrounding soft tissue could be clearly identified. Hematoxylin and eosin staining showed the tumor formation of the right infratemporal fossa region accompanied by bone destruction. Human keratin immunohistochemical staining showed that the tumor tissue originated from human squamous cell carcinoma, and the polynuclear osteoclasts could be seen at the margin of the skull base bone resorption. CONCLUSION: The animal model with malignant tumor in the skull base-infratemporal region could be successfully established via submandibular injection under ultrasound-guidance. Bone changes of the skull were easily observed on Micro-CT, but the tumor counter was not able to be distinguished from surrounding soft tissue. The 3.75% compound iodine staining of the head specimen could help discern the tumor and surrounding soft tissue in more details.

Computer-aided three-dimensional assessment of periodontal healing distal to the mandibular second molar after coronectomy of the mandibular third molar: a prospective study.

BACKGROUND: The periodontal healing distal to the mandibular second molar (M2M) after coronectomy of the M3M has shown controversial results. We aimed to combine a digital method with cone-beam computed tomography (CBCT) and estimate periodontal healing of M2M after M3M coronectomy. An accurate and stable indicator in three dimensions was also explored tentatively. METHODS: Patients with a M3M in contact with the inferior alveolar canal were included. CBCT was applied immediately after coronectomy (baseline) and 6-months later. Data were investigated with digital software for registration. Previously reported and coronectomy-related factors were included for univariate and multivariate analyses. RESULTS: A total of 181 patients (213 M3Ms) completed 6-month follow-up. Significant reduction in the distal intra-bony defect (DBD) depth of the M2M was shown (1.28 ± 1.24 mm, P < 0.001). DBD depth of the M2M at baseline was the most influential factor (r = 0.59), followed by preoperative M3M condition, age, rotation and migration of the root complex. Remaining enamel (OR = 6.93) and small retromolar space (0.67) contributed to re-contact of the root complex and M2M. Bone volume regenerated in the distal 2 mm was associated significantly with DBD-depth reduction (r = 0.74, P < 0.001). CONCLUSIONS: Bone volume regenerated in the distal 2 mm of the M2M denoted stability of distal periodontal healing of the M2M. DBD depth at baseline was the most influential factor for healing of a DBD of the M2M after M3M coronectomy. The remaining enamel and a small retromolar space could contribute to re-contact of the root complex and the M2M. TRIAL REGISTRATION: China Clinical Trial Center, ChiCTR1800014862 . Registered 10 February 2018.

[Expression of cartilage oligomeric matrix protein in the synovial chondromatosis of the temporomandibular joint].

OBJECTIVE: To detect the expression of cartilage oligomeric matrix protein (COMP) in the synovial chondromatosis of the temporomandibular joint (TMJSC), and to discuss the possible interactions between COMP, transforming growth factor (TGF)-ß3, TGF-ß1 and bone morphogenetic protein-2 (BMP-2) in the development of this neoplastic disease. METHODS: Patients in Peking University School and Hospital of Stomatology from January 2011 to February 2020 were selected, who had complete medical records, TMJSC was verified histologically after operation. The expressions of COMP, TGF-ß3, TGF-ß1 and BMP-2 in the TMJSC of the temporomandibular joint were detected by immunohistochemistry and quantitative real-time PCR (RT-PCR) at the protein level and mRNA level respectively, compared with the normal synovial tissue of temporomandibular joint. The histological morphology, protein expression and distribution of TMJSC tissues were observed microscopically, and the positive staining proteins were counted and scored. SPSS 22.0 statistical software was used to analyze the expression differences between the related proteins in TMJSC tissue and the normal synovial tissue of temporomandibular joint and to compare their differences. P < 0.05 indicated that the difference was statistically significant. RESULTS: Immunohistochemical results showed that the positive expression of COMP in TMJSC tissues was mostly found in synovial tissues and chondrocytes adjacent to synovial tissues, and the difference was statistically significant, compared with the normal temporomandibular joint synovial tissues. The positive expression of COMP was significantly different between recurrent TMJSC and non-recurrent ones. The positive expressions of TGF-ß3, TGF-ß1 and BMP-2 were higher than the normal synovial tissue, and were also mostly found in the synovial cells and adjacent chondrocytes, which was further confirmed by Western blot. According to the RT-PCR results, the expressions of COMP, TGF-ß3, TGF-ß1 and BMP-2 in TMJSC were higher than those in the normal synovial tissue. CONCLUSION: The expression of COMP in TMJSC of temporomandibular joint increased significantly, compared with the normal synovial tissue. There may be interactions between COMP and cytokines related to the proliferation and differentiation, like TGF-ß3, TGF-ß1 and BMP-2, which may play a potential role in the pathogenesis of TMJSC.

[Diagnostic test for detection of cervical lymph node metastasis from oral squamous cell carcinoma via infrared thermal imaging].

OBJECTIVE: To evaluate the diagnostic performance of a non-invasive, non-radiating, economical and convenient infrared thermal imaging in the detection of oral squamous cell carcinoma (OSCC) cervical lymph node metastasis, and evaluate its applicability via parallel test and series test. METHODS: This study was a prospective clinical study which passed the ethical review by the Biomedical Ethics Committee, Hospital of Stomatology, Peking University, and had been submitted for clinical trial registration. Totally 74 OSCC patients who were to undergo a neck dissection were included in this study. The inclusion criteria were patients who: (1) were pathologically diagnosed as malignant tumors and planned to undergo surgical treatment including neck dissection; (2) agreed to participate in this study. The exclusion criteria were those who: (1) had undergone surgeries at head and neck previously; (2) with a history of systemic tumor adjuvant therapies such as radiotherapy or chemotherapy etc; (3) were unwilling or unable to cooperate. Basal information as well as clinical examination results were collected, such as physical examination and contradictive enhanced CT. Besides, infrared thermal imaging was done ahead of surgery. Analysis of the diagnostic power of infrared thermal imaging followed the principles of diagnostic test. The positive signs of infrared thermal imaging were: (1) asymmetric thermographic pattern including vascular pattern in ROI; (2) thickening image of unilateral facial artery/vein, submental artery/vein or external carotid artery; (3) surface temperature of ROI raised over 1 °C compared with the opposite side; (4) changes of neck profile with abnormal temperature pattern. The gold standard of this diagnostic test was pathology diagnosis of cervical lymph nodes. RESULTS: The sensitivity of infrared thermal imaging was 75.0%, while the specificity was 69.0%, accuracy was 71.6%, positive predictive value was 64.9% and negative predictive value was 78.4%. The sensitivity of parallel test which stood for the combination of infrared thermal imaging and conventional clinical examinations was 87.9% while the specificity of series test was 97.6%. CONCLUSION: Infrared thermal imaging is a promising non-invasive, non-radiating and economical tool in the detection of cervical lymph node metastasis from OSCC when combined with conventional pre-operative examination.

[Accuracy analysis of robotic assistant needle placement for trigeminal gasserian ganglion].

OBJECTIVE: To evaluate the accuracy and feasibility of a custom robot system guided by optical navigation for needle puncture on trigeminal gasserian ganglion. METHODS: A synthetic human skull model was used, with plasticine placed around the skull base to imitate the human soft tissue. Cone beam CT (CBCT) scanning was performed before the operation. With image data transferred to the graphical user interface of the computer workstation, the oval foramen was selected as the target and the "skin entry point" was also determined by the surgeon on the surgical planning software. Thus the needle trajectory was eventually planned. The skull model was fixed firmly to the trial table with a head clamp and relative size of the trial table was the same as a standard operating table. Following point-based registration, the data were sent to the robot control unit. Only after the surgeon's confirmation, the needle was automatically inserted into the intended target by the robot guided by optical navigation. When the procedure was completed, the instantaneous data of the needle tip orientation acquired by navigation system was sent back to the computer workstation for accuracy verification by calculating the geometric distance between the needle tip and the planning target after matrix transformation. Subsequently, after the needle had been released, CBCT scanning was also acquired to make image fusion of the preoperative skull and the postoperative skull. The data of the needle tip orientation was acquired on the postoperative image and the accuracy was re-verified by calculating the geometric distance between the needle tip and the planning target after matrix transformation. IBM SPSS Statistics 20 was used for statistical analysis and the paired t-test was used to compare the differences in the accuracy measured by the intraoperative navigation and postoperative image fusion. RESULTS: All 20 interventions were successfully located in oval foramen at the first needle insertion. The mean deviation of the needle tip was (0.56±0.07) mm (measured by the navigation system) and (1.49±0.14) mm (measured by the image fusion), respectively (P<0.001). CONCLUSION: The experimental results show the robot system is efficient and reliable. The navigation accuracy is one of the most significant factors in robotic procedures.

[Application of digital mandibular movement record and masticatory muscle electromyography in the evaluation of stomatognathic function in patients with mandibular tumor].

OBJECTIVE: To study the clinical characteristics of mandibular movement and masticatory muscle function in preoperative and postoperative patients with unilateral mandibular tumors in the region of mandibular body and ramus by combining digital mandibular movement records with electromyography, and to preliminarily explore the relationship and mechanism between movement and masticatory muscle function. METHODS: Six preoperative patients with tumor in unilateral body and ramus of mandible were included, and three postoperative patients with unilateral segmental resection and reconstruction of mandibular bone were included. The mandibular movement recording system and surface electromyography system were used to collect the movement trajectory of the patients' mandibular marginal movement and chewing movement, and the surface electromyography of bilateral masseter and temporalis was recorded concurrently. The surface electromyography of bilateral masseter and temporalis was collected when the patients were at relaxation and at maximal voluntary clenching (MVC). The motion trajectory was observed on the digital virtual model, and the motion amplitude and direction of mandibular marginal movements were analyzed. The characteristics of masticatory electromyogram (EMG) activity in affected and unaffected sides at relaxation, MVC and bilateral mastication were analyzed, and the asymmetry indexes and activity indexes were calculated. RESULTS: The preoperative mean maximum opening of the patients was (35.20±6.87) mm. Three patients had mild mouth opening limitation, and all the patients' mouth opening trajectory was skewed to the affected side. During lateral movements, the mean range of motion of the affected side [(10.34±1.27) mm] and that of the healthy side [(6.94±2.41) mm] were significantly different. The maximum opening of the postoperative patients was (30.65±17.32) mm, and the mandibular marginal movement characteristics were consistent with those of the patients before surgery. During MVC in the preoperative patients, the median EMG activities of the masseter muscle [44.20 (5.70, 197.90) µV] and the temporalis muscle [42.15 (22.90, 155.00) µV] on the affected side were slightly lower than those of the masseter [45.60 (7.50, 235.40) µV] and the temporalis muscle [63.30 (44.10, 126.70) µV] on the healthy side. In the postoperative patients, individualized changes occurred. Some patients suffered from weakened electromyographic activity on the affected side, while some other ones showed hyperelectromyographic activity on the affected side. CONCLUSION: Both benign and malignant tumors as well as their surgery can cause abnormal mandibular movements and change of electromyographic activity of bilateral masseter and temporalis muscles.

[Multimodal image fusion technology for diagnosis and treatment of the skull base-infratemporal tumors].

OBJECTIVE: To explore the value of incorporated multimodal image fusion technology with computer-aided design of the skull base-infratemporal tumor treatment. METHODS: A retrospective study was carried out to enroll seventeen patients with skull base-infratemporal tumors treated at Peking University Hospital of Stomatology from February 2011 to September 2018. Plain CT, enhanced CT and MRI data were imported into the iPlan 3.0 software (BrainLab navigation system), and the image fusion was performed for each patient preoperatively. Then the three-dimensional images of the tumor, vital vessels and craniofacial bones were reconstructed to prepare virtual operation design. We evaluated the application of multimodal image fusion technology that had been incorporated with computer-aided planning during the navigation-guided biopsy or surgery, through the analysis of the biopsy and operation data and regular follow-up postoperatively. RESULTS: The mean age of 17 patients (7 males and 10 females) was 46 years. Primary tumors occurred in 11 cases, and recurrent tumors in 6 cases. The size of the 17 tumors ranged from 2.9 cm to 9 cm, and the mean size was 4.35 cm. There were 7 cases with skull base bone destruction and/or intracranial extension, and 10 cases with tumors adjacent to the skull base. High-quality multimodal fused images were obtained in all the 17 cases. The spatial-position relationships of the tumors, adjacent craniomaxillofacial bones and vital vessels labeled with different colors were displayed well on the generated fusion images. The multimodal image fusion technology that incorporated with computer-aided three-dimensional reconstruction and then applied in navigation-guided biopsy or surgery showed that, preoperative analysis and virtual operation design functioned with good results, especially in cases with small tumor size, recurrence or illdefined borders in the skull base-infratemporal region. Operation was carried out in 16 cases after preoperative diagnosis and assessment, and 1 case was performed by navigation-guided biopsy only. The proportions of navigation-guided surgery and biopsy were 70.6% (12/17) and 17.6% (3/17) individually. The positive rate of pathologic diagnosis using navigation-guided biopsy was 100% (3/3). All the navigation-guided biopsies or operations were carried out successfully. Complications included 1 case of cerebrospinal fluid leak from a recurred meningioma patient postoperatively, and 1 case of facial paralysis resulting from parotid-gland deep lobe tumor. Most (14/15) tumors got complete removal with safe boundary through intra-operative navigation verification and post-operative imaging confirmation, except for one case of subtotal resection to avoid the injury of cavernous sinus. The pathological results of the tumors could be classified to mesenchymal (10), adenogenous (3), neurogenic (3) or epithelial (1) resources. The follow-up time ranged from 3 to 94 months, with the median follow-up time of 9 months. CONCLUSION: Taking full advantages of individualized multimodal images, could help analyze the three-dimensional spatial position relationship of tumors, vital vessels and craniofacial bones properly, and then complete the virtual operation design well. The incorporated multimodal image fusion technology with navigation technology may improve the accuracy and safety of core needle biopsy and surgical treatment of skull base-infratemporal tumors.

[Expression of hypoxia-inducible factor 1α is associated with lymph node metastasis in oral squamous cell carcinoma].

OBJECTIVE: To explore the association between hypoxia-inducible factor 1α (HIF-1α) expression and lymph node metastasis in oral squamous cell carcinoma (OSCC). METHODS: Tumor specimens from 125 patients with histologically-proven, surgically-treated OSCC were examined by immunohistochemical staining for expression of HIF-1α. The patients were divided into two groups by the expression of HIF-1α, high expression of HIF -1α group (H-group) and low expression of HIF-1α group (L-group). The main assessment parameters were lymph node metastasis rate and disease-specific survival (DSS). The lymph node metastasis rate and clinicopathologic features were compared using Mann-Whitney test. The Kaplan-Meier curve was generated for each group and compared using the log-rank test. Cox proportional hazard models were utilized for multivariate analyses of HIF-1α expression and other baseline factors with DSS. All calculations and analyses were performed using the SPSS 17.0 software package. RESULTS: The protein expression levels of HIF-1α were up-regulated in OSCC and two patients were unable to evaluate. There were 48 patients in L-group and 75 patients in H-group. Lymph node metastasis rate was 37.5% (18/48) for L-group and 58.7% (44/75) for H-group (P=0.027). Expression of HIF-1α was significantly correlated with lymph node metastasis. The patients of L-group had a significantly better DSS than the patients of H-group (70.8% vs. 46.7%, P=0.005), while the patients of L-group had a significantly better disease-free survival (DFS) than the patients of H-group (60.4% vs. 36.0%, P=0.009) by Kaplan-Meier method. A multivariate survival analysis also showed that HIF-1α expression (HR=2.164, 95%CI: 1.150-4.074, P=0.017) and T-stage (HR=1.387, 95%CI: 1.066-1.804, P=0.015) both were the independent factors associated with prognosis. CONCLUSION: HIF-1α expression is significantly correlated with lymph node metastasis in OSCC. HIF-1α expression is an independent predictive factor for prognosis of OSCC patients, and may serve as a potential biomarker for molecular diagnosis and targeted therapy in future.

[Anatomy and histology characteristics of lymph node in nude mice].

OBJECTIVE: To compare the differences of anatomical and histological characteristics of lymph nodes between BALB/c nude mice and BALB/c mice. METHODS: Firstly, twenty BALB/c nude mice and twenty BALB/c mice were dissected by using a surgical microscope. Secondly, the differences of T cells and B cells at the lymph node were compared by the expressions of CD3 and CD20 immunohistochemistry dyes. RESULTS: There were, on average, 23 nodes per mouse contained within the large lymph node assembly in the BALB/c nude mouse. The anatomical features of the lymph node distribution in the nude mice were mainly found in the neck with relatively higher density. There were two lymph nodes both in the submandible lymph nodes group and in the superficial cervical lymph nodes group (the constituent ratios were 95% and 90%, respectively) in the BALB/c nude mice, but there were four lymph nodes (the constituent ratios were 95% and 90%, respectively) in the BALB/c mice. There were significant difference between the BALB/c nude mice and the BALB/c mice. Mostly there were two lymph nodes of deep cervical lymph nodes both in the BALB/c nude mice and the BALB/c mice (the constituent ratios were 95% and 100%, respectively). There were no significant difference between the BALB/c nude mice and the BALB/c mice. We confirmed that the number of CD3-positive T lymphocytes in lymph nodes of the nude mice decreased greatly as compared with the BALB/c mice. Expressions of CD3 in T cells were 95% and 100% in the BALB/c nude mice and in the BALB/c mice, respectively. There were significant differences between the BALB/c nude mice and the BALB/c mice. Expressions of CD20 in B cells were 95% and 100% in the BALB/c nude mice and in the BALB/c mice, respectively. There was no significant difference between the BALB/c nude mice and BALB/c mice. CONCLUSION: The anatomical pictures of lymph node distribution in the nude mouse will be benefit to those who are interested. The anatomical features of the lymph node local higher density in neck of the nude mouse and lack of CD3-positive T lymphocytes would be useful for obtaining a better understanding of localized lymph node metastasis of oral transplant tumors.

[Application of three-dimensional reconstruction of the enhanced CT with iPlan CMF software in head and neck neoplasms].

OBJECTIVE: Three-dimensional reconstruction of the enhanced CT is increasingly becoming a valuable tool in head and neck neoplasms. The aim of this study is to reconstruct three-dimensional imaging of tumor and its surrounding important anatomical structure using iPlan CMF software, and to investigate the application of three-dimensional tumor mapping technique for the diagnosis and treatment of the head and neck neoplasms. METHODS: In the study, 13 cases with head and neck tumors in Department of Oral and Maxilloficial Surgery, Peking University School and Hospital of Stomatology from June 2014 to June 2015 were studied using spiral CT scanning technology based on the same scanning condition. iPlan CMF software was used to read the original CT data, and surface shaded technology was applied to reconstruct the spatial relationship of the tumor, vessel and skull. The distance between the tumor and its surrounding important anatomical structure could be measured. iPlan CMF software was also used to accomplish the virtual osteotomy to expose the tumor, vessel and skull. The preoperative preparation, operative situation and postoperative complication were reviewed. RESULTS: In this study 6 patients were male and 7 female. The age range was from 23 to 65 years, and the median patient age was 50 years. The three-dimensional reconstruction image clearly demonstrated the extent of the tumor size, location, and the relation to its surrounding important anatomical structure. According to the three-dimensional image, the surgical risk of the patients was evaluated. The preoperative preparation and surgeries were successfully performed for 10 patients. Blood transfusion for 3 patients was considered before the surgery and actually accomplished during the operation. The operations for 2 patients were performed with the help of doctors from other departments. Only one patient had hoarseness because the tumor resulted from the pneumogastric nerves. For 10 patients, the average operation time was (202±135) min, and the average operation bleeding was (235±252) mL. The other 3 patients were not suitable cases for surgery. CONCLUSION: The three-dimensional reconstruction of enhanced CT image with iPlan CMF software is very helpful to make the treatment plan to avoid damaging important anatomical structures and postoperative complications.

[Clinical analysis of cervical lymph node metastasis of cN0 maxillary malignant tumor].

OBJECTIVE: To investigate the cervical lymphatic metastasis rates of clinically negative neck lymph node (cN0) maxillary malignant tumors, to compare the cervical lymphatic metastasis rates of the various pathological types, and to provide the reference for the treatment of the neck of the patients with cN0 maxillary malignant tumor. METHODS: The clinical data of 277 cases with cN0 maxillary malignant tumor, treated in the department of oral and maxillofacial surgery of Peking University School and Hospital of Stomatology from 1990 to 2010, were reviewed. The cervical lymph node metastasis and the related clinical information were recorded. The clinical information including histopathology type of the tumors, tumor grade, primary site and TNM staging, as well as other demographic and clinical data, were retrieved from the electronic medical record system (EMRS) of the hospital. The pathogenesis of cervical lymph node metastasis in maxillary malignant tumors of different histopathological types, and the factors related to lymph node metastasis of upper cervical malignancy were analyzed by SPSS 19.0 statistical software. RESULTS: The overall cervical lymph node metastasis rate of the 277 patients with cN0 maxillary malignant tumor was 15.5% (43/277). Maxillary squamous cell carcinoma (SCC) had a strong cervical lymph node metastasis tendency and the rate was 33.0%. The overall metastatic rate of adenocarcinoma was 7.6% lower than that of SCC, and the occurrence of cervical lymph node metastasis time was relatively late, but the metastasis rate of highly malignant grade salivary gland carcinoma was significantly higher than that of intermediate and low grade carcinoma (P=0.037). The metastatic rates of some highly malignant cN0 salivary gland carcinomas including adenocarcinoma, not other specified, high-grade mucoepidermoid carcinoma (MEC), and salivary duct carcinoma were exceeded 15%, while the metastasis rates of adenoid cystic carcinoma and myoepithelial carcinoma were lower. The metastasis rate of the sarcomas was very low with the rate of 4.9%. CONCLUSION: Selective neck dissection (SND) is recommended for cN0 maxillary SCC and feasible for some highly malignant cN0 salivary gland carcinomas including adenocarcinoma, not other specified, high-grade MEC, salivary duct carcinoma. The neck can be closely observed for the patients with maxillary sarcoma.

[Surgical reconstruction of maxillary defects using a computer-assisted techniques].

The maxilla is the most important bony support of the mid-face skeleton and is critical for both esthetics and function. Maxillary defects, resulting from tumor resection, can cause severe functional and cosmetic deformities. Furthermore, maxillary reconstruction presents a great challenge for oral and maxillofacial surgeons. Nowadays, vascularized composite bone flap transfer has been widely used for functional maxillary reconstruction. In the last decade, we have performed a comprehensive research on functional maxillary reconstruction with free fibula flap and reported excellent functional and acceptable esthetic results. However, this experience based clinical procedure still remainssome problems in accuracy and efficiency. In recent years, computer assisted techniques are now widely used in oral and maxillofacial surgery. We have performed a series of study on maxillary reconstruction with computer assisted techniques. The computer assisted techniques used for maxillary reconstruction mainly include: (1) Three dimensional (3D) reconstruction and tumor mapping: providing a 3D view of maxillary tumor and adjacent structures and helping to make the diagnosis of maxillary tumor accurate and objective; (2) Virtual planning: simulating tumor resection and maxillectomy as well as fibula reconstruction on the computer, so that to make an ideal surgical plan; (3) 3D printing: producing a 3D stereo model for prebending individualized titanium mesh and also providing template or cutting guide for the surgery; (4) Surgical navigation: the bridge between virtual plan and real surgery, confirming the virtual plan during the surgery and guarantee the accuracy; (5) Computer assisted analyzing and evaluating: making a quantitative and objective of the final result and evaluating the outcome. We also performed a series of studies to evaluate the application of computer assisted techniques used for maxillary reconstruction, including: (1) 3D tumor mapping technique for accurate diagnosis and treatment of maxillary tumor; (2) Maxillary reconstruction with free fibula flap used computer assisted techniques; (3) Computer assisted orbital floor reconstruction after maxillectomy. The results suggested that computer assisted techniques could significantly improve the clinical outcome of maxillary reconstruction.

[Applicational evaluation of split tooth extractions of upper molars using piezosurgery].

OBJECTIVE: To evaluate the efficacy of Piezosurgery in split teeth extractions. METHODS: A single-center, randomized, split-mouth study was performed using a consecutive serious of unrelated healthy patients attending the departing of oral and maxillofacial surgery, Peking University School and Hospital of Stomatology. 40 patients were selected for extraction of maxillary molars without reservation value,splitting or nonvital teeth. They were divided into control (20 patients) and test groups (20 patients) randomly. Surgical treatments for both groups were under local anesthesia. Molar teeth of control group were extracted by common equipments like dental elevators, chisels, forceps, etc. While molar teeth of experimental group were extracted by Piezosurgery, aided with the use of common equipments if needed. Then we compared the duration of surgery, frequency of the usage of chisels, expansion of postoperative bony socket surgical discomfort and postoperative pain between two groups. RESULTS: The average of operation time was (629.5±171.0) s in control group and (456.0±337.2) s in test group. The buccal alveolar bone reduced (1.07±0.64) mm in control group and (1.49±0.61) mm in test group. There was a significant difference between the two groups (P<0.05). The duration of surgery for experimental group was significantly longer than that of the control group, but the change of buccal alveolar bone was lower than the control group. For visual analogue scale (VAS) value of surgical discomfort, expansion of postoperative bony socket and the operative fear rate, there were no significant difference between the two groups (P>0.05). CONCLUSION: Piezosugery can be better to preserve alveolar bone, reduce trauma and patient's fear. Application of the piezosugery reflect the characteristics of minimally invasive extraction, which has the value of promotion. The Piezosurgery technique have the advantage of reducing change of buccal alveolar bone during the surgery, but a longer surgical time was required when compared with the conventional technique. VAS value of surgical discomfort, expansion of postoperative bony socket and the operative fear rate, there were no significant difference. Minimally invasive tooth extraction technique has good clinical results and high satisfaction. Piezosurgery proved its worth as the instrument adapted to limiting the destruction of bone tissue.

[Applicational evaluation of split tooth extractions of upper molars using piezosurgery].

OBJECTIVE: To evaluate the efficacy of Piezosurgery in split teeth extractions. METHODS: A single-center, randomized, split-mouth study was performed using a consecutive serious of unrelated healthy patients attending the departing of oral and maxillofacial surgery, Peking University School and Hospital of Stomatology. 40 patients were selected for extraction of maxillary molars without reservation value,splitting or nonvital teeth. They were divided into control (20 patients) and test groups (20 patients) randomly. Surgical treatments for both groups were under local anesthesia. Molar teeth of control group were extracted by common equipments like dental elevators, chisels, forceps, etc. While molar teeth of experimental group were extracted by Piezosurgery, aided with the use of common equipments if needed. Then we compared the duration of surgery, frequency of the usage of chisels, expansion of postoperative bony socket surgical discomfort and postoperative pain between two groups. RESULTS: The average of operation time was (629.5±171.0) s in control group and (456.0±337.2) s in test group. The buccal alveolar bone reduced (1.07±0.64) mm in control group and (1.49±0.61) mm in test group. There was a significant difference between the two groups (P<0.05). The duration of surgery for experimental group was significantly longer than that of the control group, but the change of buccal alveolar bone was lower than the control group. For visual analogue scale (VAS) value of surgical discomfort, expansion of postoperative bony socket and the operative fear rate, there were no significant difference between the two groups (P>0.05). CONCLUSION: Piezosugery can be better to preserve alveolar bone, reduce trauma and patient's fear. Application of the piezosugery reflect the characteristics of minimally invasive extraction, which has the value of promotion. The Piezosurgery technique have the advantage of reducing change of buccal alveolar bone during the surgery, but a longer surgical time was required when compared with the conventional technique. VAS value of surgical discomfort, expansion of postoperative bony socket and the operative fear rate, there were no significant difference. Minimally invasive tooth extraction technique has good clinical results and high satisfaction. Piezosurgery proved its worth as the instrument adapted to limiting the destruction of bone tissue.

[Diagnosis and treatment of diffuse tenosynovial giant cell tumor arising from temporomandibular joints].

OBJECTIVE: To retrospectively analyze the clinical features, treatment and prognosis to the diffuse tenosynovial giant cell tumor (D-TSGCT) arising from the temporomandibular joint (TMJ), and to give a reference for the early diagnosis and treatment of this disease. METHODS: In this study, 15 patients finally diagnosed as D-TSGCT of TMJ histopathologically at the Peking University Hospital of Stomatology from October 2003 to August 2015 were selected and reviewed. Their clinical manifestations, imaging and histological features, diagnoses and differential diagnoses, treatments and follow-ups were summarized and discussed. RESULTS: D-TSGCT of TMJ showed obvious female predominance (12/15), the main symptoms included painful preauricular swelling or mass, limited mouth-opening and mandibular deviation with movement. D-TSGCT on computed tomography (CT) scan often showed ill-defined soft tissue masses around TMJ, enhancement after contrast administration, usually with widening of the joint spaces and with bone destruction of the condyle, the fossa and even the skull base. On magnetic resonance images (MRI), the majority of lesions on T1 weighted images and T2 weighted images both showed the characteristics of low signals (6/11). The lesions could extend beyond the joints (9/11) and into the infratemporal fossa (4/11) and the middle cranial fossa (4/11). Surgical resection was performed in 14 cases and biopsy in 1 case. Postoperative radiotherapy was performed in 3 cases. In follow-ups, 3 cases showed recurrence postoperatively. CONCLUSION: D-TSGCT arising from TMJ should be differentiated with TMJ disorders, other tumors and tumor-like lesions of TMJ and parotid neoplasms, etc. CT and MRI examinations have important values in the diagnosis and treatment design of D-TSGCT. Because of the local aggressive and extensive behavior, complete resection should be performed as soon as possible. Postoperative radiotherapy was helpful for the extensive lesions including destruction of skull base and may be a good supplementary therapy. Because of the possibility of recurrence and malignancy, long-term follow-up was suggested.

[Research progress in multi-body system dynamics modeling in stomatology].

The stomatognathic system is an organic combination of bone, dentition, joints, masticatory muscles and innervation nerves. It is an organ system for the human body to perform mastication, speech, swallowing and other important functions. Due to the complex anatomical structure of stomatognathic system and ethical limitations, it is difficult to directly measure the movement and force by using the biomechanical experimental methods. Multi-body system dynamics is an important tool to study the kinetics and force of a multi-body system, which consists of several objects with relative motion. We can use the method of multi-body system dynamics simulation in engineering to study the movement, soft tissue deformation and force transfer of this complex stomatognathic system. This paper briefly introduces the history and application methods of multi-body system dynamics and the commonly used modeling methods. The application and research progress of multi-body system dynamics modeling methods in the field of stomatology was emphatically summarized, development prospects of current research and difficulties were put forward.

[A historical review of dental schools founded by dentist Situ Bo in modern time].

About 8 dental schools were founded by Chinese dentists during modern times (1909-1949) in China. Only one still worked after the founding of the People's Republic of China, which was one of the three dental schools founded by dentist Situ Bo. There were no systematic researches on Situ Bo's participation in dentistry education. This paper analyzes the founder's experience in dentistry and in the two schools he founded at the beginning, focusing on the background and process of the schools' construction, management, teaching, teachers and students training, etc. The results show that the establishment of the first two dental schools have laid important foundation for the establishment and development of Shanghai Dental College by the reserve of trained professional teachers and accumulated valuable experience in running schools. The systematic review of this history will help us better understand the establishment and development of Shanghai Dental College and the efforts in dentistry education made by dentists growed up in modern China, as well as the early development process of stomatology.