Background: Ameloblastoma are benign but locally invasive neoplasms that represent 10% of all odontogenic tumors. Despite its benign characteristics, ameloblastoma has a high recurrence rate after treatment with a recurrence rate of 55-90%. It is important to identify the risk factors of recurrence to improve patient’s quality of life in oral and maxillofacial surgery. Methods: Patients who underwent surgery at the Department of Oral and Maxillofacial Surgery at Pusan National University Dental Hospital for 5 years from 2017-2021 and were diagnosed with ameloblastoma as a result of postoperative histological examination were included. The patients were divided into two groups, recurrent and non-recurrent, and comparative analysis was performed according to various factors. Results: First, when the lesion was involved with the inferior alveolar nerve (IAN), recurrence was more likely than when it was not. Next, recurrence occurs more often when cortical bone perforation is observed than when it is not. In particular, when resorption is shown on the lingual cortical bone, a remarkable tendency of recurrence is shown. Moreover, in radiographic characteristics, the multicystic type showed a higher recurrence tendency than the unicystic type. Conclusion: When the lesion is multicystic, perforating the cortical bone, infiltrating the adjacent soft tissue, or involving the IAN, a high recurrence rate is shown. The results of this retrospective analysis of the recurrence trend of ameloblastoma over a 5 years period are to contribute significantly to insight and reduction of recurrence rates in treatment for polymorphic lesion in oral and maxillofacial area.

In this study, the positions of Cs-137 gamma ray source are estimated from the plastic scintillating fiber bundle sensor with length of 5 m, using machine learning data analysis. Seven strands of plastic scintillating fibers are bundled by black shrink tube and two photomultiplier tubes are used as a gamma ray sensing and light measuring devices, respectively. The dose rate of Cs-137 used in this study is 6 μSv·h−1. For the machine learning modeling, Keras framework in a Python environment is used. The algorithm chosen to construct machine learning model is regression with 15,000 number of nodes in each hidden layer. The pulse-shaped signals measured by photomultiplier tubes are saved as discrete digits and each pulse data consists of 1,024 number of them. Measurements are conducted separately to create machine learning data used in training and test processes. Measurement times were different for obtaining training and test data which were 1 minute and 5 seconds, respectively. It is because sufficient number of data are needed in case of training data, while the measurement time of test data implies the actual measuring time. The machine learning model is designated to estimate the source positions using the information about time difference of the pulses which are created simultaneously by the interaction of gamma ray and plastic scintillating fiber sensor. To evaluate whether the double-trained machine learning model shows enhancement in accuracy of source position estimation, the reference model is constructed using training data with one-time learning process. The double-trained machine learning model is designed to construct first model and create a second training data using the training error and predetermined coefficient. The second training data are used to construct a final model. Both reference model and double-trained models constructed with different coefficients are evaluated with test data. The evaluation result shows that the average values calculated for all measured position in each model are different from 7.21 to 1.44 cm. As a result, by constructing the double-trained machine learning model, the final accuracy shows 80% of improvement ratio. Further study will be conducted to evaluate whether the double-trained machine learning model is applicable to other data obtained from measurement of gamma ray sources with different energy and set a methodology to find optimal coefficient.

The myxoma(odontogenic myxoma, myxofibroma) of the jaws is a benign, usually slow-growing infiltrative tumor of connectice tissue. This article describes a case history of the treatment of recurred odontogenic myxofibroma in the maxilla and further discusses the appropriate management of such cases with reference to the literature review. A 55-year-old male patient presented with a gingival swelling in the right side of maxilla. He had history of second time recurred disease. Microscopically, a high cellularity fibrous tumor with fibroblastic cells was observed. Tumor cells were composed of stellate and spindle shaped fibroblasts. Islands of odontogenic epithelium were seen in the specimen. The final diagnosis was made with odontogenic myxofibroma in consideration of twice-time recurrences and histological characteristics. Because of the high likelihood of recurrence, an accurate differential diagnosis of pathology at the time of initial visit is very important in determining treatment options, and immunohistochemical tests may be helpful. Also close following up is required.(155 words)

In this study, we investigated the effect of bisphosphonate on the osteoblastic differentiation of human dental stem cells (hDPSCs). In the first experiment, we evaluated the effect of bisphosphonate on the differentiation of hDPSCs into osteoblasts by alkaline phosphatase staining after culturing hDPSCs. As a result, on day 13, the osteogenic differentiation of hDPSC was suppressed at 5 μM in clodronate and 2 μM in zolendronate. In NBP, osteogenic differentiation is more suppressed. In second experiment, cytotoxicity and proliferation test, the cell proliferation (examined by MTT assay) was more suppressed as the concentrations of zolendronate were larger than those of alendronate and clodronate. Western blotting, a third experiment, was found that AKT phosphorylation was inhibited in cell signaling proteins involved in cell proliferation inhibition and death by bisphosphonate concentration. In human dental stem cells, bisphosphonates inhibit osteoblast differentiation, and this phenomenon is clearly observed in NBPs (zolendronate), and it has been found that it is related to AKT phosphorylation of cell signaling proteins.

Eugenol is an essential oil found in cloves and cinnamon that is used widely in perfumes. However, the significant anesthetic and sedative effects of this compound have led to its use also in dental procedures. Recently, it was reported that eugenol induces apoptosis in several cancer cell types but the mechanism underlying this effect has remained unknown. In our current study, we examined whether the cytotoxic effects of eugenol upon human melanoma G361 cells are associated with cell cycle arrest and apoptosis using a range of methods including an XTT assay, Hoechst staining, immunocytochemistry, western blotting and flow cytometry. Eugenol treatment was found to decrease the viability of the G361 cells in both a time- and dose-dependent manner. The induction of apoptosis in eugenol-treated G361 cells was confirmed by the appearance of nuclear condensation, the release of both cytochrome c and AIF into the cytosol, the cleavage of PARP and DFF45, and the downregulation of procaspase-3 and -9. With regard to cell cycle arrest, a time-dependent decrease in cyclin A, cyclin D3, cyclin E, cdk2, cdk4, and cdc2 expression was observed in the cells after eugenol treatment. Flow cytometry using a FACScan further demonstrated that eugenol induces a cell cycle arrest at S phase. Our results thus suggest that the inhibition of G361 cell proliferation by eugenol is the result of an apoptotic response and an S phase arrest that is linked to the decreased expression of key cell cycle-related molecules.

Chios gum mastic (CGM) is a resin produced from the stem and leaves of Pistiacia lentiscus L var chia, a plant which grows only on Chios Island in Greece. CGM has been used for many centuries as a dietary supplement and folk medicine for stomach and duodenal ulcers in many Mediterranean countries and is known also to induce cell cycle arrest and apoptosis in some cancer cells. In this study, we further investigated the induction and mechanisms underlying the apoptotic response to CGM treatment in the SCC25 human tongue squamous cell carcinoma cell line. The viability of SCC25 cells, human normal keratinocytes (HaCaT cells) and human gingival fibroblasts (HGF-1 cells), and the growth inhibition of SCC25 cells were assessed by MTT assay and clonogenic assay, respectively. Staining with Hoechst and hemacolor dyes and TUNEL assays were employed to detect SCC25 cells undergoing apoptosis. SCC25 cells were treated with CGM, and this was followed by western blotting, immunocytochemistry, confocal microscopy, FACScan flow cytometry, MMP activity and proteasome activity analyses. CGM treatment of SCC25 cells was found to result in a time- and dosedependent decrease in cell viability, a dose-dependent inhibition of cell growth, and apoptotic cell death. Interestingly, CGM showed a remarkable level of cytotoxicity in SCC25 cells but not in normal cells. Tested SCC25 cells also showed several lines of apoptotic manifestation. Taken together, our present findings demonstrate that CGM strongly inhibits cell proliferation by modulating the expression of G1 cell cycle-related proteins and induces apoptosis via the proteasome, mitochondria and caspase cascades in SCC25 cells.

The content of four phonolic acids 1-4, and two flavonol aglycones 14 and 15 from Orostachysjaponicus A. Berger grown under night-break and day-length controlled experiments was estimated and compared with those in wild plants. The amount of the phenolic acids 1-4 and the flavonol aglycones 14 and 15 increased with increasing light irradiation under both the night-break and day-length control conditions. It was disclosed that the cultivation conditions such as the night-break and the day-length control were not adversely affect the production of phenolic acids and flavonols in Orostachys japonicus A. Berger extracts.