이 연구는 통합기술수용이론(UTAUT)을 확장한 UTAUT2 모델을 활용 하여 치의학과 학생들의 UBT 수용의도에 영향을 미치는 요인을 분석하 고, 성별에 따른 조절효과를 검토하였다. 이를 위해 한 국립대학교 치의 학과 졸업시험에 응시한 학생 157명을 대상으로 설문조사를 실시하였다. 설문조사는 연구참여자의 성별, 나이, 입학 유형, 태블릿 PC 보유 여부, 스마트기기 활용 능력 등 인구통계학적 정보와 스마트기기 사용 경험, 그리고 UTAUT2 모델에 기반한 성과기대, 노력기대, 사회적 영향, 촉진 조건, 습관 등 요인과 UBT 수용의도를 평가하는 21개의 문항 등 총 27 개의 문항을 활용하였다. 설문조사 분석 결과에 따르면 사회적 영향과 습관 요인이 치의학과 학생들의 UBT 수용의도에 유의미한 영향을 미쳤 으며, 습관 요인과 UBT 수용의도간 관계에 대한 성별의 조절효과가 확 인되었다. 이러한 결과를 바탕으로 UBT 도입을 촉진하기 위해 학생들의 긍정적인 인식을 높이는 홍보 활동, 정기적인 연습 기회 제공, 성별 맞춤 형 접근, 기술적 지원과 자원 제공 등의 전략을 제안하였다.

목적 : 치과에서 광중합기 사용 시 착색 안경렌즈가 청색광으로부터 눈을 보호하기 위해 사용하는 큐링실드를 대용할 수 있는지를 알아보고자 하였다. 방법 : 광중합기 부착형인 큐링실드와 염료의 색과 착색 시간을 달리한 착색 렌즈들의 광투과율을 측정하였다. 결과 : 큐링실드의 청색광과 가시광선 투과율이 각각 0.63%와 48.88%로 나타났다, 60분과 90분 동안 착색한 오렌지색 착색 렌즈의 청색광 투과율은 각각 0.82%와 0.59%, 가시광선 투과율은 48.14%와 47.50%로 큐링실드와 비슷하게 나타났다. 90분 동안 착색된 노란색 착색 렌즈의 청색광 투과율은 12.43%, 가시광선 투과율은 56.94% 이었다. 60분 이상 착색된 갈색과 회색 착색 렌즈의 청색광 투과율은 2.00% 미만이었고 가시광선 투과율은 25.00% 미만이었다. 결론 : 오렌지색 착색 렌즈는 청색광 차단효과가 우수하고 큐링실드와 비슷한 밝기를 확보할 수 있어서 큐링실 드를 대체할 수 있으리라 본다. 노란색 착색 렌즈는 착색 시간을 90분보다 더 길게 한 추가연구가 필요해 보인다. 갈색과 회색 착색 렌즈에서 큐링실드와 유사한 청색광차단 효과를 얻으려면 밝기가 어두워지는 문제를 고려해야 할 것으로 보인다.

Background: In healthy dentin conditions, odontoblasts have an important role such as protection from invasion of pathogens. In mammalian teeth, progenitors such as mesenchymal stem cells (MSCs) can migrate and differentiate into odontoblast-like cells, leading to the formation of reparative dentin. For differentiation using stem cells, it is crucial to provide conditions similar to the complex and intricate in vivo environment. The purpose of this study was to evaluate the potential of differentiation into odonto/ osteoblasts, and compare co-culture with/without epithelial cells. Methods: MSCs and epithelial cells were successfully isolated from dental tissues. We investigated the influences of epithelial cells on the differentiation process of dental pulp stem cells into odonto/osteoblasts using co-culture systems. The differentiation potential with/without epithelial cells was analyzed for the expression of specific markers and calcium contents. Results: Differentiated odonto/osteoblast derived from dental pulp tissue-derived mesenchymal stem cells with/without epithelial cells were evaluated by qRT-PCR, immunostaining, calcium content, and ALP staining. The expression of odonto/ osteoblast-specific markers, calcium content, and ALP staining intensity were significantly increased in differentiated cells. Moreover, the odonto/osteogenic differentiation capacity with epithelial cells co-culture was significantly higher than without epithelial cells co-culture. Conclusions: These results suggest that odonto/osteogenic differentiation co-cultured with epithelial cells has a more efficient application.

Previous researches have revealed that dental panoramic radiographs routinely taken in dental clinics can be useful to diagnose low bone density. The purpose of this study is to investigate the prevalence, awareness and treatment rate of low bone density of females utilizing dental panoramic images. Four-hundred-and-fifteen female patients(mean age 70.4 yrs ± 11.4 yrs) between the age of 50s to 90s, at Chonnam National University Dental Hospital were randomly selected for this study. The panoramic radiographs taken from the patients were reviewed for the purpose of interpreting suspected low bone density(SLBD) on the basis of mandibular cortex index. Awareness and treatment rates of osteoporosis were investigated based on electronic records using the past medical history. As a result, the prevalence rate was 42.17%(175 in 415), the osteoporosis-awareness rate 22.3%(39 in 175), and the treatment rate 87%(34 in 39), showing that the osteoporosis-awareness rate was low, but the treatment rate was relatively high. In conclusion, it can be suggested that osteoporosis-awareness rate by diagnosing SLBD with dental panoramic radiographs be increased to help patients to receive proper treatment.

This study aimed to investigate which areas AI is sensitive when inputting panoramic radiographs with dental area masked and when inputting unmasked ones. Therefore, the null hypothesis of this study was that masking dental area would not make a difference in the sensitive areas of osteoporosis determination of AI. For this study 1165 female(average age 48.4 ± 23.9 years) from whom panoramic radiographs were taken were selected. Either osteoporosis or normal should be clearly defined by oral and maxillofacial radiologists. The panoramic radiographs from the female were classified as either osteoporosis or normal according to the mandibular inferior cortex shape. VGG-16 model was used to get training, validating, and testing to determine between osteoporosis or normal. Two experiments were performed; one using unmasked images of panoramic radiographs, and the other using panoramic radiographs with dental region masked. In two experiments, accuracy of VGG-16 was 97.9% with unmasked images and 98.6% with dental-region-masked images. In the osteoporosis group, the sensitive areas identified with unmasked images included cervical vertebrae, maxillary and mandibular cancellous bone, dental area, zygomatic bone, mandibular inferior cortex, and cranial base. The osteoporosis group shows sensitivity on mandibular cancellous bone, cervical vertebrae, and mandibular inferior cortex with masked images. In the normal group, when unmasked images were input, only dental region was sensitive, while with masked images, only mandibular cancellous bone was sensitive. It is suggestive that when dental influence of panoramic radiographs was excluded, AI determined osteoporosis on the mandibular cancellous bone more sensitively.

In this study, we successfully grafted chitosan (CS) onto multi-walled carbon nanotubes (MWCNTs) to enhance their properties and potential applications in the biomedical field. FTIR spectroscopy confirmed the successful covalent bonding of CS onto MWCNTs, indicated by the new absorption peak of the amide bond (–CONH–). Thermal analysis showed that the modified MWCNTs (MWCNT-CS) had significant weight loss around 260 °C, suggesting the decomposition of hydroxypropyl chitosan, and confirming its presence in the nanocomposite. SEM images revealed that CS grafting improved the dispersibility of MWCNTs, a property crucial for their use as nanofillers in polymers. Moreover, the micro-tensile bond strength of dentin surface increased with increasing MWCNT-CS concentrations, indicating the potential of MWCNT-CS as a pretreatment for dentin bonding. After simulated aging, the bond strength remained significantly higher for MWCNT-CS groups compared to those without pretreatment. In biocompatibility assessment using the MTT assay, MWCNT-CS showed higher cell viability than MWCNT, suggesting improved biocompatibility after CS modification. The results of this study suggest that CS-modified MWCNTs could be promising materials for applications in dentin bonding, dentin mineralization, bone scaffolding, implants, and drug delivery systems.

This study evaluated cell viability and cytokine release in immortalized human oral fibroblasts (hTERT-hNOFs) and keratinocytes (IHOK) exposed to a dental-impregnated gingival retraction cord. To prepare the extracts, dental gingival retraction cords impregnated with aluminum chloride hexahydrate were immersed in a cell culture medium for 24 h at 37 °C. hTERT-hNOFs and IHOK were cultured for 24 h. The cell culture medium was removed and extracts of the dental gingival retraction cords were added. After incubation with the extract solution, cell viability was evaluated using an MTT assay. The levels of the cytokines IL-1α and IL-8 were measured in the supernatants of each cell type. The cell viability after exposure to the extract solution for 10 min exceeded 70 % in both cell types. The ET50 values for hTERT-hNOF and IHOK were 35.75 and 28.98 min, respectively. For IHOK, the IL-1α level was (5.35 ± 5.22) pg/mL at 10 min, (3.58 ± 5.38) pg/mL at 20 min, and (2.85 ± 4.28) pg/mL at 60 min of exposure (p > 0.05). The IL-8 level in IHOK was (67.16 ± 18.70) pg/mL at 10 min, (78.36 ± 7.50) pg/mL at 20 min, and (111.9 ± 26.10) pg/mL at 60 min of exposure (p > 0.05). Cytokine release was not observed from hTERThNOFs. Based on these results, cell viability and cytokine release were confirmed in cells exposed to the impregnated gingival retraction cord. In addition, the application of the extracts to hTERT-hNOF and IHOK during the actual contact time and determination of ET50 may be beneficial for evaluating the biocompatibility of dental-impregnated gingival retraction cords.

Bioactive flavonoids have been shown to improve the biological activity of stem cells derived from different sources in tissue regeneration. The goal of this study was to see how naringin, a natural flavonoid discovered in citrus fruits, affected the biological properties of human dental pulp stem cells (HDPSCs). In this study, we found that naringin increases the migratory ability of HDPSCs. Naringin increased matrix metalloproteinase-2 (MMP-2) and C-X-C chemokine receptor type 4 (CXCR4) mRNA and protein expression in HDPSCs. ARP100, a selective MMP-2 inhibitor, and AMD3100, a CXCR4 antagonist, both inhibited the naringin-induced migration of HDPSCs. Furthermore, naringin increased osteogenic differentiation of HDPSCs and the expression of the osteogenic-related marker, alkaline phosphatase in HDPSCs. Taken together, our findings suggest that naringin may be beneficial on dental tissue or bone regeneration by increasing the biological activities of HDPSCs.

Bisphosphonate-associated osteonecrosis (BRONJ) is an adverse event associated with bisphosphonate drug treatment. An 81-year-old female has been taking bisphosphonates orally once a month for three years complained of pain in the left mandibular molar area after implant placement. Tenderness and fistula were formed. Extensive osteosclerosis in posterior area of the left mandible and bone resorption around distal side of #37i were shown on radiographs. She was given oral antibiotics for 6 weeks and bone resorption was improved. A 70-year-old male had a history of intravenous injection of bisphosphonates for blood cancer complained of #46i implant mobility. There was buccal fistula on #45 site. Radiographically, severe bone resorption and extensive osteosclerosis were shown. He was treated with removal of implant and inflammatory tissue. Patients who have taken bisphosphonates may develop BRONJ after tooth extraction or implant placement and are needed to meticulous plaque control for preventing BRONJ.

To investigate the perceptions and attitudes of dental hygienists toward radiation safety management in Korea. A total of 800 dental hygienists were randomly selected for an anonymous survey, and 203 of them participated. The questionnaire items included the following: sex, career period, type of installed radiographic equipment, recognition of the diagnostic reference level (DRL), participation in radiation safety education, and attitudes toward radiation protection for both patients and dental hygienists. The participants were divided into two groups according to their years of experience (< 10 years versus ≥ 10 years). The difference between the groups was investigated according to frequency distribution. Fisher’s exact test or Pearson’s chi-square (χ2) test was used as appropriate. A regression analysis was performed to investigate the impact of wearing a thyroid collar for personnel protection during patient radiation exposure. The types of installed radiographic equipment included panoramic radiography (96.1%), cephalometric radiography (76.9%), intraoral radiography (72.9%), and cone-beam computed tomography (69.5%). Significant differences were observed in the learning pathway for the DRL (Fisher’s exact test, p < 0.05), satisfaction with radiation safety education (Pearson’s χ2 test = 5.3975, Pr = 0.02), and use of personnel radiation monitoring systems (Pearson’s χ2 test = 18.1233, Pr = 0.000) between the groups. Significant differences were also observed in personnel protection using a thyroid collar and patient protection during panoramic radiography (odds ratio = 14.2). Dental hygienists with more than 10 years of experience were more satisfied with radiation safety education and more interested in radiation monitoring. Considering career experience, customized, continuous, and effective radiation safety management education should be provided.

This study was performed as a part of serial experiments of applying convolutional neural network(CNN) in determining osteoporosis on panoramic radiograph. The purpose of this study was to investigate how sensitively CNN determine osteoporosis on cropped panoramic radiograph. Panoramic radiographs from 1268 female patients(mean age 45.2 ± 21.1 yrs) were selected for this study. For the osteoporosis group, 633(mean age 72.2 ± 8.5 yrs) were selected, while for the normal group 635(mean age 28.3 ± 7.0 yrs). AlexNet was utilized as CNN in this study. A multiple-column CNN was designed with two rectangular regions of interest on the mandible inferior area. An occluding method was used to analyze the sensitive area in determining osteoporosis on AlexNet. Testing of AlexNet showed accuracy of 99% in determining osteoporosis on panoramic radiographs. AlexNet was sensitive at the area of cortical and cancellous bone of the mandible inferior area including adjacent soft tissue.

Dental health care workers (DHCW) are at a risk of occupational exposure to Helicobacter pylori from the aerosolized oral biofilms and saliva of patients. We designed this study to investigate the prevalence of H. pylori in the oral biofilms of a group of dental and non-dental undergraduates from Sri Lanka. After obtaining informed consent, oral biofilms were collected from 38 dental undergraduates (19 males and 19 females) undergoing clinical training and 33 non-dental undergraduates (14 males and 19 females). The participants were in the age range of 22–27 years and had healthy periodontium. Total DNA from the oral biofilms were extracted, and H. pylori DNA was detected using polymerase chain reaction (PCR) amplification of 16S rRNA gene of H. pylori using JW22-JW23 primers, and the results were confirmed using PCR amplification of H. pylori -urease specific HPU1-HPU2 primers. Out of 71 participants, 11 (28.95%) dental and 3 (9.09%) non-dental undergraduates had H. pylori in their oral biofilms indicating an overall prevalence rate of 19.72% (14/71). Thus, the prevalence of H. pylori in oral biofilms was significantly higher in dental undergraduates than in non-dental undergraduates (p < 0.05). An odds ratio of 4.07 indicated that dental undergraduates were four times more likely to harbor H. pylori in their oral biofilms than nondental undergraduates. Foregoing data support the fact that there may be greater occupational risk of exposure to H. pylori for dental undergraduates during clinical training than that for non-dental undergraduates, warranting meticulous infection control practices during clinical dentistry.

Mesenchymal stem cells in the dental pulp exhibit a tendency for differentiation into various dental lineages and hold great potential as a major conduit for regenerative treatment in dentistry. Although they can be readily isolated from teeth, the exact characteristics of these stem cells have not been fully understood so far. When compared to twodimensional (2D) cultures, three-dimensional (3D) cultures have the advantage of enriching the stem cell population. Hence, 3D-organoid culture and 3D-sphere culture were applied to dental pulp cells in the current study. Although the establishment of the organoid culture proved unsuccessful, the 3D-sphere culture readily initiated the stable generation of cell aggregates, which continued to grow and could be passaged to the second round. Interestingly, a significant increase in SOX2 expression was detected in the 3D-spheroid culture compared to the 2D culture. These results indicate the enrichment of the stemness-high population in the 3D-sphere culture. Thus, 3D-sphere culture may act as a link between the conventional and 3D-organoid cultures and aid in understanding the characteristics of dental pulp stem cells.

漢語 中古音의 聲母의 조음 방법을 연구함에 있어, 『東國正韻』(1447)과 『訓蒙字會』 (1527)는 중요한 자료가 될 수 있다. 漢語 中古音을 음소 문자로 표기한 최초의 문자 는 파스파 문자이지만, 파스파 문자는 死語가 되어 음소의 변화 및 후대의 계승 양 상을 확인할 방법이 없다. 반면, 『東國正韻』 한자음은 漢語 中古音과 시기상으로는 거리가 있지만, 漢語 中古音의 운미 8개를 일률적으로 訓民正音으로 표기했고, 全淸·次淸·全濁·次濁 역시『訓民正音』 ｢解例本｣에서 명확히 정의하고 있다.『訓蒙字會』는 우리 현실 한자음을 반영하고 있다고 분석되므로, 『東國正韻』 한자음의 표기가 『訓蒙字會』에서 어떻게 반영되는지를 살필 경우, 『東國正韻』의 편찬자가 분석한 漢 語 中古音의 淸·濁音의 일면을 엿볼 수 있다. 이 중에서 漢語 中古音의 齒音을 고찰 하면서, 淸音의 무성 마찰음 /s/와 全濁의 유성 마찰음 /z/에 대해서 주로 연구하고 자 한다. 일반적으로 漢語 中古音의 全濁 齒音은 /z/로 추정되는데, 『東國正韻』 편찬 자의 관점에서도 그러한지 살펴보는 것이다. 『東國正韻』 한자음의 성격에 대해 異論 이 있어 본고에서는 논외로 하지만, 『訓蒙字會』의 한자음과 비교해서 살펴봤을 때, 『東國正韻』은 표기에서 우리 한자음을 바탕으로 漢語 中古音 四聲七音의 원리를 반영 하고 있다고 평가하는 것을 근거로 본고에서의 논의를 전개한다. 따라서 당시 우리 현실 한자음을 비교적 잘 반영하고 있는 『訓蒙字會』의 한자음을 기준으로 『東國正韻』의 한자음과 면밀히 고찰해 볼 때, 漢語 中古音의 淸·濁音의 특징에 대해 자세히 살펴볼 수 있다.

We investigated the current status of institutional review boards (IRBs) that oversee research in dental hospitals. Eight hospitals, all of which had IRB, responded to our e-mail. The questions comprised two topics: IRBs and the clinical trials approved by them. The results showed that the average number of staff on IRBs of the 8 hospitals was 12.5. Furthermore, the proportion of dentists was the highest among the science committee members, with an average of 7.75, and the average number of non-dentists among the non-scientific members was 1.8. Regular IRBs convened meetings more than once a month, over the past year, or only if necessary.According to the approval status of clinical trials from 2016 to 2019, less than 50 studies accounted for 75%. The materials related to dental-implant procedures accounted for the highest quantity of materials used during clinical trials at 33.3%. The duration of 50% of the clinical trials ranged from more than 1 year to less than 2 years.Thus, based on the hypothesis that institutional reviews are currently conducted at dental hospitals and have raised issues and suggested improvements, we believe that IRBs will play an important role in dental hospitals, with more research conducted in dentistry in the future.

This study was conducted as part of a series of studies to introduce the Convolutional Neural Network(CNN) into the diagnostic field of osteoporosis. The purpose of this study was to compare the results when testing Digital Radiography(DR) and Computed Radiography(CR) panoramic radiographs by CNN that were trained by DR panoramic radiographs. The digital panoramic radiographs of females who visited for the purpose of diagnosis and treatment at Chonnam National University Dental Hospital were taken. Two Oral and Maxillofacial Radiologists were selected for the study to compare the panoramic radiographs with normal and osteoporosis images. Among them, 1068 panoramic radiographs of females{Mean [± standard deviation] age: 49.19 ± 21.91 years} obtained by DR method were used for training of CNN. 200 panoramic radiographs of females{Mean [± standard deviation] age: 63.95 ± 6.45 years} obtained by DR method and 202 panoramic radiographs of females{Mean [± standard deviation] age: 62.00 ± 6.86 years} obtained by CR method were used for testing of CNN. When the DR panoramic radiographs were tested, the Accuracy was 92.5%. When the CR panoramic radiographs were tested, the Accuracy was 76.2%. It can be seen that the CNN trained by DR panoramic radiographs is suitable to be tested with the same DR panoramic radiographs.

Telomeres are known as a specialized region in the end of chromosomes to protect DNA destruction, but their lengths are shortened by repetition of cell division. This telomere shortening can be preserved or be elongated by telomerase and TERT expression. Although a certain condition in the cells may affect to the cellular and molecular characteristics, the effect of differentiation induction to telomere length and telomerase activity in mesenchymal stem cells (MSCs) has been less studied. Therefore, the present study aimed to uncover periodical alterations of telomere length, telomerase activity and TERT expression in the dental pulp-derived MSCs (DP-MSCs) under condition of differentiation inductions into adipocytes and osteoblasts on a weekly basis up to 3 weeks. Shortening of telomere was significantly (p < 0.05) identified from early-middle stages of both differentiations in comparison with undifferentiated DP-MSCs by non-radioactive chemiluminescent assay and qRT-PCR method. Telomere length in undifferentiated DP-MSCs was 10.5 kb, but the late stage of differentiated DP-MSCs which can be regarded as the adult somatic cell exhibited 8.1-8.6 kb. Furthermore, the relative-quantitative telomerase repeat amplification protocol or western blotting presented significant (p < 0.05) decrease of telomerase activity since early stages of differentiations or TERT expression from middle stages of differentiations than undifferentiated state, respectively. Based on these results, it is supposed that shortened telomere length in differentiated DP-MSCs was remained along with prolonged differentiation durations, possibly due to weakened telomerase activity and TERT expression. We expect that the present study contributes on understanding differentiation mechanism of MSCs, and provides standardizing therapeutic strategies in clinical application of MSCs in the animal biotechnology.

Streptococcus mutans is one of the important bacteria that forms dental biofilm and cause dental caries. Virulence genes in S. mutans can be classified into the genes involved in bacterial adhesion, extracellular polysaccharide formation, biofilm formation, sugar uptake and metabolism, acid tolerance, and regulation. The genes involved in bacterial adhesion are gbps (gbpA, gbpB, and gbpC) and spaP. The gbp genes encode glucan-binding protein (GBP) A, GBP B, and GBP C. The spaP gene encodes cell surface antigen, SpaP. The genes involved in extracellular polysaccharide formation are gtfs (gtfB , gtfC , and gtfD ) and ftf , which encode glycosyltransferase (GTF) B, GTF C, and GTF D and fructosyltransferase, respectively. The genes involved in biofilm formation are smu630, relA , and comDE. The smu630 gene is important for biofilm formation. The relA and comDE genes contribute to quorumsensing and biofilm formation. The genes involved in sugar uptake and metabolism are eno, ldh , and relA . The eno gene encodes bacterial enolase, which catalyzes the formation of phosphoenolpyruvate. The ldh gene encodes lactic acid dehydrogenase. The relA gene contributes to the regulation of the glucose phosphotransferase system. The genes related to acid tolerance are atpD, aguD, brpA, and relA . The atpD gene encodes F1F0-ATPase, a proton pump that discharges H+ from within the bacterium to the outside. The aguD gene encodes agmatine deiminase system and produces alkali to overcome acid stress. The genes involved in regulation are vicR, brpA, and relA .