The Department of Oral and Maxillofacial Pathology was established in March 1970 by Dr. Young Pill Cho. Successive chairpersons of the department have included Dr. Han Kook Cho, Dr. Jaeo Cho, Dr. Eun Chull Kim, and Dr. Sang Wook Kang, who held the position until 2021. The tasks of the Department of Oral Pathology include conducting lectures and laboratory work for undergraduate dental students, as well as for graduate students pursuing MSD and PhD degrees. The department also engages in research within the field of oral pathology and provides diagnostic services for tissues obtained from diseases affecting the oral and maxillofacial regions. The objectives of the department are to equip students with the appropriate knowledge and skills to diagnose and develop accurate treatment plans for diseases affecting oral and maxillofacial structures through lectures and laboratory work after graduation. Since the establishment of the Master's and PhD programs in Oral and Maxillofacial Pathology, a total of 94 individuals have completed the Master's program, 45 individuals have completed the PhD program, and 1 individual has completed the Master-PhD collaboration program. Each participant completed their respective courses and obtained the appropriate degrees following the evaluation of their graduation theses.

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.

The oral cavity is rich in blood flow, which can cause excessive bleeding. Excessive bleeding in oral cavity is rare, but if the cause of the bleeding is not found, the patient's life may be at risk. Therefore, in the case of excessive bleeding, the dentist should consider the cause and provide appropriate first treatment. Hydrofluoric acid is widely used as a material for pre-treatment of ceramics before oral restoration for prosthetics and conservative dentistry. Since hydrofluoric acid is very reactive, when it comes into contact with tissues, even very diluted 0.1% hydrofluoric acid can cause very painful 2-3 degree burns, which heal very slowly. Negative reactions and even deaths of hydrofluoric acid have been reported in other fields, but there are very few case reports of complications related to hydrofluoric acid in the dental field. In this article, we report a case of excessive gingival bleeding after restorative treatment and discuss the effects of hydrofluoric acid on oral soft tissues and blood vessels and its prevention

One of the most demanded competencies of an oral health professional such as an oral pathologist is the ability to make clinical decisions. The purpose of this study was to examine the neurological differences between beginners and experts in the clinical decision-making process which consisting of complex, dynamic and sophisticated cognitive processes, and to identify the characteristics of experts based on the brain by comparing EEG activity. This study conducted experimental design with 10 dentists with more than 10 years of clinical experience and 10 students with short clinical experience as beginners as a fourth year student before graduation. The hypothesis-oriented algorithm proposed in HOAC II was used. As a standard, the clinical decision-making stage of the dentist was divided into three stages, and an event was developed and an experiment was designed for measuring EEG for each stage. The cerebral activity distribution patterns of the two groups were measured with EEG, compared and analyzed with pre-processing process using EEGlab. As a result, the difference in the auditory information was not noticeable between the novice and the expert, but the difference between the group of the novice and the expert appeared in the visual data and the radiographic data. In the case of beginners, the activity was higher in the left hemisphere, and in the case of experts, both brains were activated. The results of this study are intended to present objective information based on brain-based analysis of differences that appear in the clinical decision-making process of experts and beginners. It can be used as basic research data to present the brain-based characteristic analysis of dentist experts.

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.

본 연구의 목적은 치과종사자의 손씻기에 대한 건강신념과 손씻기 수행도 간의 관련성을 파악하여 평가하는 것이다. 본 연구는 치과의원, 치과대학병원에서 근무하는 140명의 치과종사자를 대상으로 구조화된 설문지를 사용하여 자가보고식으로 작성하도록 하였다. 모든 자료는 통계분석은 t검정, 일원분산 분석, Pearson 상관계수분석으로 통계처리 하였다. 손씻기 수행도는 손씻기에 대한 건강신념과 r=0.285로 양의 상관관계를 보였다(p<0.01). 치과의원, 치과대학병원에서 근무하는 치과종사자의 병원감염 예방을 실천하기 위해서는 감염관리 교육 시 지각된 민감성, 지각된 심각성, 지각된 유익성, 지각된 장애성, 수행을 위한 동기로 구성된 손씻기에 대한 건강신념을 고려하고, 지속적인 손씻기 교육을 시행한다면 치과종사자의 손씻기 수행도도 증가할 것으로 사료된다.

Guided tissue regeneration(GTR) is regenerative operating technique at dental clinic. The vertical bone defect can be treated by GTR. The purpose of this study is to present the importance of GTR at dental clinic. The vertical bone defect was observed on distal side of mandibular right 2nd molar. The patient had been treated scaling, root planing and GTR. Both nonresorbable occluding membrane and resorbable occluding membrane can be used as GTR operation. The former was used in this study. Nonresorbable occluding membrane can exclude epithelial cells from healing defect. The Bio-Oss bone graft used at GTR operation. A radiograph demonstrates that the regenerative part was observed by GTR. In conclusion, GTR operating effect has importance on vertical defect at dental clinic.

With the multiple practices of bone graft using different artificial bone regenerative substitutes, the bone graft procedures have been widely performed to increase the bony stabilization of dental implant. Xenogenic bone graft materials have been well developed because of their good biocompatibility and abundant source of bone materials. The present study demonstrated the histological findings from excellent bony remodeling in xenogenic bone graft biopsies compared to those findings in autogenous bone graft. For the graft bone biopsies which were usually done in 5-9 months after graft bone insertion, five types of histological grades including excellent, favorable, partial, degenerative, and poor bony remodeling could be assessed to give prognostic information for dental implant. However, recently the xenograft bone materials have been much improved and produced strong osteogenic effect. Among 239 cases of trephine bur-supported core bone biopsy the excellent bony remodeling was found in 20 cases (13.1%) out of 153 xenogenic bone grafts and in 13 cases (43.3%) out of 30 autogenous bone grafts. They produced abundant new bones on the surface of the graft bones in 5–9 months, and the graft bones were partly resorbed and also surrounded by the repetitive deposition of new bone. The osteophytic new bones showed strong birefringence under polarizing microscope, and were gradually elongated and anastomosed with each other to form trabecular bony networks which became proper stress-baring structures for dental implant. Their marrow stromal tissues were composed of loose connective tissue which was well vascularized but rarely infiltrated with inflammatory cells. The present study compared the histological features of excellent bony remodeling between xenogenic and autogenous bone grafts. Although the ratio of excellent bony remodeling in xenogenic bone graft was still low, 13.1%, the recent advance of xenogeic bone products was remarkable in biological aspect and almost comparable to the autogenous bones. Therefore, it was suggested that the xenogenic bone graft will be applicable to the bone regeneration procedures for dental implant with beneficial output in the near future.

Development of a dental three-dimensional laser scanning system and measure the accuracy of new adjustable upper and lower dental impression tray was performed. The master model and the duplicated casts were digitized using an dental scanning system. The distance between the reference points were measured and analyzed on the graphic image of 3D graphic software of CATIA. The statistical significance of the differences between the groups was determined by a two-way ANOVA. There were no significant differences between the accuracies of the adjustable stock tray and the master model except only anterior arch width on the upper and lower arch. The adjustable upper and lower stock tray showed clinically acceptable accuracies of the study cast produced by them.

A 57 years old female received xenogenic bone graft for the extraction socket augmentation of right maxillary molars and for the sinus floor elevation six months ago. The bone graft sites were healed uneventfully and showed marked radiopacity in the postoperative X-ray view. Before dental implant insertion the bone biopsy was made using trephine bur and examined pathologically. The graft bones showed minimum new bone deposition with dysplastic epithelium. The epithelium was proliferative on the surface of graft bones forming epithelial strands and nests, similar to the odontogenic epithelium. The immunohistochemical study was performed using different antisera of odontogenic markers, growth factors, oncogenes, etc. The epithelial cells were strongly positive for pan-keratins, EGF, pAKT, and HSP-70, consistently positive for PCNA, p53, EGFR, 14-3-3, and survivin, slightly positive for ameloblastin, but rarely positive for amelogenin. Particularly the matrix of graft bone was slightly positive for EGF. Taken together, it is presumed that the abnormal epithelium on the graft bones was derived from odontogenic epithelial elements, Malassez epithelial rests, distributed at the periodontal tissue of maxillary molars, and that they might undergo dysplastic proliferation affected by the release of growth factors and osteogenic proteins from the graft bones. It is also suggested that the graft bone substitutes inserted for the dental implant possibly have a potential to induce the proliferation of odontogenic epithelial rests leading to the pathogenesis of odontogenic cysts and tumors.

This research presents a preparation method of dental components by metal injection molding process (MIM process) using titanium scrap. About 20 μm sized spherical titanium powders for MIM process were successfully prepared by a novel dehydrogenation and spheroidization method using in-situ radio frequency thermal plasma treatment. The effects of MIM process parameters on the mechanical and biological properties of dental components were investigated and the optimum condition was obtained. After sintering at 1250oC for 1 hour in vacuum, the hardness and the tensile strength of MIMed titanium components were 289 Hv and 584 MPa, respectively. Prepared titanium dental components were not cytotoxic and they showed a good cell proliferation property.

A 72 years old male complained of gingival ulceration and whitish discoloration on the marginal and attached gingival epithelium of left mandibular premolar and molar area, where a porcelain-fused metal (PFM) crown and an ill-fitting gold crown were applied for 10 years, respectively. Recently he had a cancer phobia due to this whitish lesion unhealed even after intensive anti-inflammatory and antibiotic treatment. In the pathological examination the epithelium was hyperkeratotic and acanthomatous with severe inflammatory reaction, and subsequently its basement membrane was distorted and the intercellular spaces between keratinocytes were widened. Particularly, the nuclei of keratinocytes were elongated in the same direction towards the electric current between the dissimilar metallic crowns of PFM gold. In the immunohistochemistry KL1, β-catenin, and S-100 were strongly positive in the epithelium, but consistently weak for TNFα, HSP-70, and β-defensin-1, -2, -3. On the other hand, PCNA, p53, E-cadherin, and pAKT were rarely positive for the epithelium. Interestingly, the hyperkeratinized and inflamed epithelium was strongly positive for a calcium binding protein (S-100), while it showed almost reduced expression of protective molecules (HSP-70, β-defensin-1, -2, -3, and pAKT). Therefore, it was presumed that this localized lichenoid gingivitis was caused by the galvanic current phenomenon with lower cellular and immunological responses contrary to the ordinary oral lichen planus and leukoplakia

Poor oral hygiene can cause severe periodontal disease. Therefore, it is necessary to educate individuals regarding the importance of maintaining good oral hygiene. To this end, in this study, we evaluated the efficacy of using a phase contrast microscope as an instructional tool for oral hygiene. Forty patients, randomly divided into test and control groups, were recruited 6 months after receiving oral prophylaxis. A phase control microscope was used as a demonstration tool for the test group, and a dentiform model was used to demonstrate the ideal tooth-brushing method for the control group. In the test group, awareness regarding the importance of proper oral hygiene was found to increase by 30%, and in the control group, awareness was increased by 20%. The overall satisfaction with the instructional program was 80% in the test and 70% in the control group. The level of understanding was 99% in the test and 80% in the control group. Instructions were easily followed by 80% of the test and 60% of the control group. Understanding of the program was significantly higher in the test group than in the control group (p < 0.05). The overall satisfaction and understanding of proper oral hygiene was over 70% for both the groups. The phase contrast microscope-based instructional program yielded higher actual practice rates. The phase contrast microscope is desirable tool for motivating patients and spreading awareness regarding the importance of maintaining good oral hygiene.

We demonstrate optical cross-sectional imaging system implemented with high-resolution interferometry and present oral diagnostic imaging results obtained without any physical sectioning. High-resolution interferometry could be performed with utilizing broadband optical source and employment of beam scanning device to high-resolution interferometer constitutes optical imaging system for non-invasive cross-sectional view at real-time. The optical imaging system is implemented with fiber-optic devices for compactness and optical probe head is realized by using single mode optical fiber and miniaturized actuator, which is properly designed for the application to dental imaging. The basic performance of the optical imaging system, for example, such as resolution, imaging depth, and sensitivity is suggested to prove high-resolution optical imaging performance. Feasibility of the developed optical imaging system performance in the application of dental diagnostic is proved with demonstrating non-invasively obtained cross-sectional images. The imaging quality suggested in the images could be applied to assessment of oral diseases and used for alternative imaging modality to X-ray diagnostic method overcoming disadvantage of low-image resolution. The imaging performance enabling real-time image reconstruction also could be exploited as early oral diagnostic apparatus prior to microscopic observation under H&E staining.

The rise of medical knowledge and awareness of the importance of dental and stomatognathic system increase the patients who visit dental emergency room. The chief complaints of patients who visited the emergency room varies from a pain, trauma, hemorrhag. The purpose of this study was to classify dental emergency patients by chief complaint and to analyze in indiviual group and to provide more effective emergency dental care. This study was carried out with 1129 patients visiting emergency room of the dankook university dental hospital from 7/2011 to 6/2012. Dental emergency patients was classified trauma, pain, hemorrhage group by chief complaint and studied mothly, the day of the week, time, age distribution and cause of the individual group. The chief complaint of visiting emergency room were trauma 660 people (58.5%), pain 347 people (30.7%), hemorrhage 96 (8.5%), other 26 patients (2.3%). The monthly distribution was observed in May (12.8%), March (10.5%), September (10.2%). The trauma patients were frequent in the spring and early summer but painful patients visited in September (12.7%) and May (11.8%) in March (11.2%). The peak age group was 20 to 29 years(20.9%), followed by 0 to 9 years(19.4%), 40 to 49years (15.2%,). In trauma group the peak age was under the age of 10 (31.7%), followed by 10 to 19 years (18.8%), 20 to 29 years (17.1%) . However, in pain group, peak age was 20 to 29 years (26.8%) followed by 40 to 49 years(21.3%), 30 to 39 years (19.6 %). The most common cause of trauma were subluxation(16.5%), laceration13.7%), uncomplicated crown fracture(12.05%) and in pain group was pulpal origin(46.1%), followed by periodontal origin( 20.7%), post op pain(8.9%). Undefined pain or neuralgia were 7.9%. The most common cause of hemorrhage was post extraction( 66.7%), post operation(16.7%), spontaneous bleeding due to periodontitis(12.5%). In conclusion, the trauma, pain were different in monthly distribution and the peak age of patients. Dental emergeny doctor should understand pattern of indiviual emergency group and perform proper diagnosis and treatment for more effective emergency care.

Dentists are known to be highly exposed to the musculoskeletal disorders (MSD). The present study investigated the prevalence of MSD among Korean dentists and association between their MSD and physical workload. In addition, detailed causes related to the physical workloads were identified in dental operation, and needs for improvement of dental instrument and environment were collected from Korean dentists. The standardized Nordic questionnaire was used to survey body troubles and three types of questionnaires were made to investigate the physical workloads, causes of the physical workloads and improvement priority of dental equipments, respectively. A total of 104 Korean dentists were participated in the survey. Neck trouble (82%) was the most prevalent in Korean dentists, and shoulder (68%) and low back trouble (56%) followed, while low back trouble was reported to be most frequent in previous studies. The body troubles were related to the physical workload of the corresponding body parts, although they were not associated with personal characteristics. Most Korean dentists selected ‘to keep direct view inside patient’s mouth’ and ‘no support of the hand with dental instruments’ as the causes of awkward and strenuous work postures. They wanted design improvement for some equipment in their operating room such as operating light and arrangement of workplace.

본 논문은 두 편으로 구성된 치과용 임플란트 구조설계에 대한 논문 중 두 번째 논문으로 첫 번째 논문에서 구조해석 비 교연구를 통하여 그 구조적 성능이 확인된 새로운 임플란트 구조모델에 대하여 시험 설계도면을 작성하여 완성하였으며, 이를 근거로 실제로 CNC 공작기계 등을 이용하여 임플란트를 가공․제작하고, 이를 평가함으로써 치과용 임플란트 구조 설계를 완성하였다. 설계도면 작업은 전용 Tool인 MDT를 이용하여 수행하였으며, 가공작업은 CNC 선반, 범용밀링머신, Wire EDM 등을 이용하여 수행하였다. 전자현미경을 이용하여 임플란트 표면의 가공 상태를 최종 평가 확인하였다. 평가 결과 매우 양호한 상태의 임플란트 시험제품을 설계 제작하였다.

본 논문은 두 편으로 구성된 치과용 임플란트 구조설계에 대한 논문 중 첫 번째 논문으로 먼저 치과용 임플란트의 종류 및 특징에 대하여 조사 분석을 수행하였다. 이를 통하여 현재 사용 중인 대표적인 치과용 임플란트들의 장단점들을 비교분 석하였다. 그 결과를 토대로 새로운 임플란트 구조모델을 제안하였다. 특히 제안된 새로운 구조형상의 임플란트에 대하여 기존의 대표적인 임플란트들과 유한요소해석 기법을 이용한 구조해석 비교연구를 수행하였다. 구조해석 비교연구를 수행한 결과 본 논문에서 제안한 치과용 임플란트의 구조적 성능의 우수성이 확인되었다. 본 연구에서 구조해석 비교연구를 수행한 치과용 임플란트 제품은 3i 임플란트 제품과 Sargon 임플란트 제품이다. 이들은 모두 수입 제품들인데 임플란트 종류 및 특 징 조사 결과 현재 임상으로 사용 중인 임플란트들은 대부분 골내식립형인데 이들도 그들 중 하나임을 알 수 있었다.

The dental infections have been increased due to the widespread overuse and exposure to antibiotics. One of the well-known pathogens is S. aureus The pathogenic properties of S. aureus is associated with the virulence gene. The objective of this study is to investigate the distribution of virulence gene of S. aureus which may contribute to the prevention and treatment of bacterial infections. 54 strains of S. aureus were separated from saliva taken from 129 outpatients diagnosed with periodontitis from Jun. to Dec., 2010 in Seoul. 44 (46.6%) and 13 (31.7%) strains of them were obtained from 88 and 41 outpatients from the S and E dental clinics, respectively. Then, the distribution of virulence gene and genetic diversity were analyzed with the PCR technique. The result of the S. aureus isolates possessed coagulase gene and showed six polymorphism types 390~470 bp (1.8%), 550~633 bp (3.7%), 630~714 bp (9.3%), 715~795 bp (20.4%), 796~876 bp (40.7%) and 877~957 bp(22.2%) due to variable numbers of tandem repeats present within the gene. In this study it will be anticipated that this study can contribute to establish efficiently the countermeasure about the prevention and treatment of antibiotic bacterial infections.