The roles of heteromorphic crystals and organic compounds in the formation of the submandibular stones.

Objective: The study aimed to analyze the formation process of submandibular stones based on the theory of biological mineralization and inorganic crystal structure variation. Study design: From January 2021 to December 2021, patients with submandibular stones treated in the Affiliated Hospital of Stomatology, Sun Yat-sen University (Guangzhou, China) were selected. According to the criterion of maximum transverse diameter ≥3 mm, a total of five submandibular stones meeting the requirement were included. After the surface of sample stones were washed, they were cut along the maximum transverse diameter. Next, the study employed Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and polycrystalline X-ray Diffraction (XRD) to analyze the composition and structure of submandibular stones. Results: Five submandibular stones were included. The organic and inorganic compounds showed a rhythmic or irregular distribution. Submandibular stones were highly occupied with carbon (C), oxygen (O), calcium (Ca), and phosphorus (P). Hydroxyapatite (HAP) was the primary inorganic component. In addition, the precursor of HAP, namely Amorphous Calcium Phosphate (ACP), was also found. Tetrahedral Substitution Index (TSI) and Ca/P ratio reflected the degree of structural variation in HAP crystal, which fluctuated from 5.62-90.71 and 1.10-1.35, respectively. Conclusions: The development of submandibular stones was influenced by inorganic crystals' chemical and structural variation as well as the organics' regulation towards the inorganic. The isomorphic substitution was accompanied by the occurrence of inorganic crystals, resulting in the crystal structure change. Organics might influence the appearance, aggregation, and mineralization of HAP during its formation.

Multiple benign fibrous histiocytomas of the mandible: A case report and review of the literature.

Benign fibrous histiocytoma (BFH) mostly occurs on the skin of the extremities, while it is unusual to manifest on the bone and mandibular involvement of BFH is even rarer. The present study reports a case of BFH in a 42-year-old female who had a slowly progressive swelling of the bilateral mandible and slight facial asymmetry over a period of 4 months. However, the outcome of this patient was unsatisfactory, with the first and second recurrence observed 16 and 46 months after surgery, respectively. The present case suggests that BFH has a risk of recurrence after transoral curettage. Regular follow-up is advised to detect tumor recurrence after the surgery of transoral curettage.

Nomogram to predict the risk of endoscopic removal failure with forceps/baskets for treating submandibular stones.

BACKGROUND: Endoscopic removal with forceps/baskets is favored in treating submandibular stones due to its minimal invasiveness. However, recent studies have found that endoscopic removal failure (ERF) is not unusual, and stones in such cases still need to be removed with other surgical methods. If the risk of ERF can be predicted preoperatively, it could be helpful for surgeons when choosing the appropriate therapy. AIM: To develop a predictive nomogram for the risk of ERF when treating submandibular stones based on their preoperative clinical features. METHODS: A total of 180 patients with 211 submandibular stones treated from January 2012 to December 2020 were included in the current study. Based on the preoperative clinical features of the stones, independent risk factors for ERF were identified by logistic regression analysis. The stones were then randomly divided into training and testing sets. A nomogram was constructed to predict the risk of ERF using the training set and then validated using both sets. The predictive performance of the nomogram was assessed by calibration curves and the concordance index (C-index). RESULTS: Three independent predictors, location (P = 0.040), transverse diameter (P < 0.001) and longitudinal diameter (P < 0.001) measured on the cone beam computed tomography (CBCT) images of the submandibular stones, were identified and included in the predictive nomogram. Calibration curves of the nomogram showed good agreement between the predicted and observed probabilities in both sets. The C-index in the training set was 0.917 (95%CI, 0.875-0.959) and that in the testing set was 0.925 (95%CI, 0.862-0.989). CONCLUSION: A nomogram based on the location, transverse and longitudinal diameters on CBCT images of submandibular stones showed satisfactory efficacy in predicting the risk of ERF preoperatively when treating submandibular stones.

Primary clinical study of radiomics for diagnosing simple bone cyst of the jaw.

OBJECTIVE: To screen the radiomic features of simple bone cysts of the jaws and explore the potential application of radiomics in pre-operative diagnosis of jaw simple bone cysts. METHODS: The investigators designed and implemented a case-control study. 19 patients with simple bone cysts who were admitted to the Department of Maxillofacial Surgery, Sun Yat-sen University Affiliated Stomatology Hospital from 2013 to 2019 were included in this study. Their clinical data and cone-beam computed tomography (CBCT) images were examined. The control group consisted of patients with odontogenic keratocyst. CBCT imaging features were analyzed and compared between the patient and control groups. RESULTS: Overall, 10,323 image features were extracted through feature analysis. A subset of 25 radiomic features obtained after feature selection were analyzed further. These 25 features were significantly different between the 2 groups (p < 0.05). The absolute value of correlation coefficient was 0.487-0.775. Gray-level co-occurrence matrix (GLCM) contrast, neighborhood gray tone difference matrix (NGTDM) contrast, and GLCM variance were the features with the highest correlation coefficients. CONCLUSIONS: Pre-operative radiomics analysis showed the differences between simple bone cysts and odontogenic keratocysts, can help to diagnose simple bone cysts. Three specific texture features-GLCM contrast, NGTDM contrast, and GLCM variance-may be the characteristic imaging features of simple bone cysts of the jaw.

Development and Validation of a Prognostic Nomogram for Postoperative Recurrence-Free Survival of Ameloblastoma.

PURPOSE: Ameloblastoma is a benign odontogenic neoplasm with a high local recurrence rate if the operation is not thorough. However, a useful clinical tool for the quantitative assessment of the prognosis and risk of postoperative recurrence of ameloblastoma has not yet been constructed. This study aims to develop a prognostic nomogram model for ameloblastoma of the jaw to assist surgeons in surgical decision-making. PATIENTS AND METHODS: Patients who underwent initial surgery for ameloblastoma in our department from October 2004 to March 2020 were enrolled and randomly divided into training and validation sets. Univariate and multivariate Cox proportional hazards regression analyses were performed to identify the independent prognostic factors, from which a nomogram for predicting 3-, 5- and 10-year recurrence-free survival (RFS) of ameloblastoma was constructed using the training set and internally validated using the validation set. The model performance was assessed by Harrell's concordance index (C-index) and calibration curves. RESULTS: A total of 302 eligible patients with ameloblastoma were enrolled, 54 of whom were confirmed to relapse during the follow-up period of 6 to 191 months. Four independent predictors, including cortical bone perforation, root(s) resorption, WHO classification, and treatment pattern, were identified and included in the construction of a nomogram for recurrence-free survival (RFS), which showed promising calibration performance and discrimination in the training set (C-index 0.790, 95% confidence interval [CI] 0.735-0.845) and the validation set (C-index 0.734, 95% CI 0.599-0.869). CONCLUSION: A favorable nomogram was developed that accurately predicted the RFS of patients with ameloblastoma based on individual characteristics. Risk stratification using the nomogram could optimize tailored therapy and follow-up.

Differences between epithelial and mesenchymal human tongue cancer cell lines in experimental metastasis.

Distant metastasis represents the outcome with the worst prognosis for various types of malignant tumors, but little is known regarding the impact of interacting epithelial and mesenchymal phenotypic cancer cells within its etiopathogenesis. In a novel animal model, 48 male athymic Balb/c nude mice underwent subcutaneous and intravenous injection of human tongue cancer cell lines of green fluorescent mesenchymal and red fluorescent epithelial phenotypes, in order to visualize and monitor eventual phenotypic interaction in lung metastasis as well as experimental metastasis in in vivo, ex vivo and histopathological analyses. While the epithelial, but not the mesenchymal, phenotypic human tongue cancer cell line led to direct metastasis in the lungs when injected intravenously, neither of them, even when injected in combination, were able to establish distant metastasis. The results of the present study provide evidence regarding the role of epithelial phenotypic cancer cells in the release of experimental metastasis following tail vein injection in male athymic Balb/c nude mice, in addition to proving fluorescent human tongue cancer cells may be reliably detected under a fluorescence microscope even 8 weeks after the two injection types.

Evidence of phenotypic stability after transduction of fluorescent proteins in two human tongue cancer cell lines.

OBJECTIVES: This study investigated the phenotypic stability and biological properties of two human tongue cancer cell lines after transduction of fluorescent proteins. DESIGN: The human tongue cancer cell lines UM1 and UM2 were cultured with GFP and RFP lentiviral particles stock for 72h. Cells with successful transduction of fluorescent proteins were selected in a medium containing G418 antibiotics for two weeks. The proliferation rates of parental and transduced cell lines were evaluated by their population doubling time (PDT). Transduction efficiency was assessed by fluorescence microscope and flow cytometry. The transduced cells in passage 1, 2, 10, 20 and 30 were collected to check the stability of fluorescent protein expression. Phenotypic stability of the transduced cells was detected by means of cell morphology, cell surface markers and cell function evaluating essay. RESULTS: The proliferation rates of the transduced cell lines showed no significant difference compared to their parental cells. Successful transduction with high efficiency (99% up) was demonstrated. High fluorescence expression on both transduced cells was detected until the thirtieth generation. UM1 and UM1-GFP displayed mesenchymal cell characteristics, while UM2 and UM2-RFP cell lines showed properties characteristic of epithelial. CONCLUSIONS: Two human tongue cancer cell lines of epithelial and mesenchymal phenotype respectively, have been successfully labelled with green and red fluorescent proteins. The fluorescence maintained a high expression rate over thirty generations without influencing the original morphological phenotype and cadherin expression.

Tumorigenicity and Validity of Fluorescence Labelled Mesenchymal and Epithelial Human Oral Cancer Cell Lines in Nude Mice.

Tumorigenicity and metastatic activity can be visually monitored in cancer cells that were labelled with stable fluorescence. The aim was to establish and validate local and distant spread of subcutaneously previously injected fluorescence transduced human tongue cancer cell lines of epithelial and mesenchymal phenotype in nude mice. A total of 32 four-week-old male athymic Balb/c nude mice were randomly allocated into 4 groups (n = 8). A single dose of 0.3 mL PBS containing 1 × 107 of four different cancer cell-lines (UM1, UM1-GFP, UM2, and UM2-RFP) was injected subcutaneously into the right side of their posterolateral back. Validity assessment of the labelled cancer cells' tumorigenicity was assessed by physical examination, imaging, and histology four weeks after the injection. The tumor take rate of cancer cells was similar in animals injected with either parental or transduced cancer cells. Transduced cancer cells in mice were easily detectable in vivo and after cryosection using fluorescent imaging. UM1 cells showed increased tumor take rate and mean tumor volume, presenting with disorganized histopathological patterns. Fluorescence labelled epithelial and mesenchymal human tongue cancer cell lines do not change in tumorigenicity or cell phenotype after injection in vivo.

Effect of Granulocyte-Colony Stimulating Factor on Endothelial Cells and Osteoblasts.

OBJECTIVES: Some animal studies showed that granulocyte-colony stimulating factor (G-CSF) provides beneficial environment for bone healing. It has been well documented that endothelial cells and osteoblasts play critical roles in multiple phases of bone healing. However, the biological effects of G-CSF on these cells remain controversial. This study aimed to investigate the influence of G-CSF at various concentrations on endothelial cells and osteoblasts. MATERIALS AND METHODS: Human umbilical vein endothelial cells (HUVECs) and human osteoblasts (hOBs) were treated with G-CSF at 1000, 100, 10, and 0 ng/mL, respectively. The capacity of cell proliferation, migration, and tube formation of HUVECs was evaluated at 72, 8, and 6 hours after treatment, respectively. The capacity of proliferation, differentiation, and mineralization of hOBs was evaluated at 24 hours, 72 hours, and 21 days after treatment, respectively. RESULTS: HUVECs treated with 100 and 1000 ng/mL G-CSF showed a significantly higher value comparing with controls in migration assay (p < 0.001, p < 0.01, resp.); the group treated with 1000 ng/mL G-CSF showed a significantly lower value on tube formation. No significant difference was detected in groups of hOBs. CONCLUSIONS: G-CSF showed favorable effects only on the migration of HUVECs, and no direct influence was found on hOBs.

Skeletal site-specific response to ovariectomy in a rat model: change in bone density and microarchitecture.

OBJECTIVES: Ovariectomized (OVX) rat model has been widely used in osteoporosis-related studies. However, the discrepancies in age and skeletal sites being investigated make it difficult to compare the results from different studies. The purpose of this study was to provide information of systemic skeletal site-specific changes in a stable OVX rat model. MATERIAL AND METHODS: Thirty-three 6-month Spraque-Dawley female rats were used. Fifteen rats underwent ovariectomy, and fifteen received sham surgery. Three animals without any surgery were sacrificed at week 0 to serve as baseline. Three animals in the OVX and sham group, respectively, were euthanized at week 2, 4, 12, 24 and 36 post-surgery. Ten bone sites, including parietal bone, interparietal bone, maxilla, mandible, humerus, ulna, femur, tibia, lumber vertebra, and ilium, were subjected to micro-CT. RESULTS: Overall, long bones, lumber vertebra, and ilium showed similar trend of bone loss post-OVX, with tibia and femur suffered the most bone loss and spine the least (decreased by 75.0%, 70.4% and 36.6% in bone mineral density BMD at week 36 from base line, respectively). Upon OVX, jaw bones and cranial bones only showed a minor reduction in BMD (decreased by 1~3% from baseline) at week 36. Significant deterioration of trabecular structure was detected in long bones, lumber vertebra, and ilium post-OVX, while jaw bones remained relatively stable. CONCLUSIONS: This study for the first time assessed the systemic site-specific bone loss and microarchitecture changes in OVX rat model. It provided valuable information for selecting bone site and observation time in osteoporosis-related study.

Influence of non-steroidal anti-inflammatory drugs (NSAIDs) on osseointegration of dental implants in rabbit calvaria.

AIM: Until recently, adverse effects of non-steroidal anti-inflammatory drugs (NSAIDs) on osseointegration of dental implants were unknown. Hence, this study investigated the short- and long-term effects of a 7-day regimen of parecoxib and diclofenac sodium on osseointegration of dental implants in calvarial bone. MATERIAL AND METHODS: Eighteen New Zealand White rabbits were randomly allocated into three groups (each n = 6): Control group with no postoperative pain killers (Group A), diclofenac group (Group B) and parecoxib group (Group C). In each animal, one dental implant was placed into the calvarial bone (total n = 18). Three rabbits from each group were sacrificed in Week 4. The other three rabbits from each group were sacrificed in Week 12 postoperatively. The implant together with the calvarial bone and dura mater was harvested and subjected to micro-computed tomography (micro-CT) and histomorphometric analysis. RESULTS: Quantitative analysis of micro-CT data and histomorphometric data neither revealed any statistically significant (P ≤ 0.05) differences between the three different groups related to osseointegration nor between different time points of observation. CONCLUSION: In rabbits, a 7-day regimen of appropriate doses of diclofenac sodium and parecoxib did not adversely affect osseointegration of dental implants and bone healing in calvaria, neither short nor long term (12 weeks).

Incidence, Risk Factors and Consequences of Emergence Agitation in Adult Patients after Elective Craniotomy for Brain Tumor: A Prospective Cohort Study.

UNLABELLED: Emergence agitation is a frequent complication that can have serious consequences during recovery from general anesthesia. However, agitation has been poorly investigated in patients after craniotomy. In this prospective cohort study, adult patients were enrolled after elective craniotomy for brain tumor. The sedation-agitation scale was evaluated during the first 12 hours after surgery. Agitation developed in 35 of 123 patients (29%). Of the agitated patients, 28 (80%) were graded as very and dangerously agitated. By multivariate stepwise logistic regression analysis, independent predictors for agitation included male sex, history of long-term use of anti-depressant drugs or benzodiazepines, frontal approach of the operation, method and duration of anesthesia and presence of endotracheal intubation. Total intravenous anesthesia and balanced anesthesia with short duration were protective factors. Emergence agitation was associated with self-extubation (8.6% vs 0%, P = 0.005). Sedatives were administered more in agitated patients than non-agitated patients (85.7% vs 6.8%, P<0.001). In conclusion, emergence agitation was a frequent complication in patients after elective craniotomy for brain tumors. The clarification of risk factors could help to identify the high-risk patients, and then to facilitate the prevention and treatment of agitation. For patients undergoing craniotomy, greater attention should be paid to those receiving a frontal approach for craniotomy and those anesthetized under balanced anesthesia with long duration. More researches are warranted to elucidate whether total intravenous anesthesia could reduce the incidence of agitation after craniotomy. TRIAL REGISTRATION: ClinicalTrials.gov NCT00590499.

Effect of ovariectomy on stimulating intracortical remodeling in rats.

OBJECTIVE: Technically primates and dogs represent ideal models to investigate diseases characterized by abnormal intracortical remodeling. High expenses and ethical issues, however, restrict the use of those animals in research. Rodent models have been used as alternatives instead, but their value is limited, if none, because these animals lack intracortical bone remodeling. This study aimed at investigating the effect of ovariectomy onto the stimulation of intracortical remodeling in rat mandibles. MATERIALS AND METHODS: Sixteen 12-week-old Spraque-Dawly (SD) female rats were randomly assigned into two groups, receiving either ovariectomy or sham operation. All the rats were sacrificed 18 weeks postoperatively. The entire mandibles were harvested for microcomputed tomography (micro-CT) and histomorphometric assessments. RESULTS: Micro-CT examination showed significantly decreased bone mineral density (0.95 ± 0.01 versus 1.01 ± 0.02 g/cm(3), P < 0.001) and bone volume (65.78 ± 5.45 versus 87.41 ± 4.12%, P < 0.001) in ovariectomy group. Histomorphometric assessment detected a sixfold increased intracortical bone remodeling as well as an increased bone modeling in mandibles of ovariectomized rats. CONCLUSION: For the first time, to the authors' knowledge, it was detected that ovariectomy stimulates intracortical remodeling in rat mandibles. This animal model might be of use to study various bone diseases associated with an abnormal intracortical remodeling process.

Effect of different rhBMP-2 and TG-VEGF ratios on the formation of heterotopic bone and neovessels.

Bioengineered bone substitutes might represent alternatives to autologous bone grafts in medically compromised patients due to reduced operation time and comorbidity. Due to the lack of an inherent vascular system their dimension is limited to the size of critical bone size defect. To overcome this shortcoming, the experiment tried to create heterotopic bone around vessels. In vivo, a two-component fibrin and thrombin gel containing recombinant bone morphogenic protein (rhBMP-2) and transglutamate vascular endothelial growth factor (TG-VEGF) in different ratios, respectively, was injected into a dimensionally stable membrane tube, wrapped around the femoral vessel bundle in twelve New Zealand white rabbits. Sacrifice occurred eight weeks postoperatively. Microcomputed tomography of the specimens showed significantly increased bone volume in the rhBMP-2 to TG-VEGF ratio of 10 to 1 group. Histology showed new bone formation in close proximity to the vessel bundle. Immunohistochemistry detected increased angiogenesis within the newly formed bone in the rhBMP-2 to TG-VEGF ratios of 3 to 1 and 5 to 1. Heterotopic bone was engineered in vivo around vessels using different rhBMP-2 and TG-VEGF ratios in a fibrin matrix injected into a dimensionally stable membrane tube which prevented direct contact with skeletal muscles.

Heterotopic bone formation around vessels: pilot study of a new animal model.

To achieve an easily established, safe, and reproducible animal model for the study of heterotopic bone formation around vessels, a small animal series using New Zealand White rabbits was performed. Three different dosages of recombinant human bone morphogenic protein (rhBMP-2) carried by fibrin matrix were tested. A guided tissue regeneration (GTR) membrane sheet was formed into a tube and allowed to harden; it served both to maintain the space around the vessel bundle and to separate the fibrin matrix with rhBMP-2 from skeletal muscle. Wrapped around the femoral vessel bundle and fixed in place, the tube was filled with the fibrin matrix containing rhBMP-2. The surgical site was closed in layers, and the postoperative healing was uneventful. All animals resumed their full preoperative daily activities 3-4 days after the operation. No adverse events such as wound dehiscence or infection occurred, and all animals could be sacrified at the scheduled date. Micro-computed tomography and histological investigations showed heterotopic bone formation around the vessel bundle in the medium- and high-dosage rhBMP-2 groups. An easy, safe, and reproducible animal model that allows the study of heterotopic bone formation around vessels was successfully established.