As of August 1, 2024, Professor Young Soo Jung has begun his term as the 18th Dean of Yonsei University College of Dentistry (YUCD). Below is his inaugural address.
YUCD traces its origins to 1915, when Dr. William J. Scheifley, an American missionary dentist, founded Korea's first dental clinic at Severance Hospital. Since then, YUCD has led innovations in dental education, including the establishment of Korea’s first Predoctoral Student Clinic and Continuing Education Center, as well as introducing digital technologies like the PACS system in 2004.
YUCD is committed to training ethical and responsible dentists who embody a spirit of service and patient-centered care, in accordance with its mission: "In the spirit of God, creativity leading compassionate dentistry to serve humanity." At the same time, YUCD ensures that students are well-prepared to face the challenges of the Fourth Industrial Revolution by incorporating digital education tools and advanced clinical training into its curriculum.
Alongside its educational leadership, YUCD has secured significant national research projects, such as BK21 and MRC, keeping it at the forefront of dental research. The college also offers global continuing education programs, attracting dental professionals from around the world. By striving to meet global standards, including pursuing accreditation by the Commission on Dental Accreditation (CODA), YUCD continues to cement its reputation as a world leader in dental education, research, and patient care, while upholding its legacy of excellence.
YUCD Taste Research Center Secures $7 Million Grant, Advancing Toward Global Leadership
The YUCD Taste Research Center has been selected as a “Center for Convergence Research on Taste-Oral Functions” under the Medical Research Center(MRC) project by the Ministry of Science and ICT and the National Research Foundation.
The MRC project aims to strengthen national research capabilities in biotechnology and healthcare by fostering research groups in medicine, dentistry, Korean medicine, and pharmacy. Led by Prof. Seok Jun Moon from the Department of Oral Biology, the Taste Research Center will receive more than 7 million USD in government funding over the next seven years.
Originally established in 2016 as part of the MRC project, the Taste Research Center will now continue building on the research achievements of its first phase. The center plans to map taste receptors and study their functions and correlation with diseases by using human genomes, animal model, and human organoid platforms. Additionally, the center aims to promote industrialization through collaborations with industry.
Prof. Moon stated, "Taste is more than just an organ for detecting flavors; it plays a vital role in regulating numerous body functions. Our goal is to conduct interdisciplinary, collaborative research to decode unknown functions of taste receptors and improve oral functionality, ultimately positioning the center as a world-class leader in this field."
Prof. Chung-Min Kang Receives Minister’s Award at 13th Population Day
Prof. Chung-Min Kang from the Department of Pediatric Dentistry received the prestigious Minister’s Award from the Ministry of Health and Welfare during the 13th Population Day on July 11. This recognition was awarded in acknowledgment of her significant contributions toward addressing the national challenge of the low birth rate.
Prof. Kang developed a specialized oral care program aimed at improving the health and development of preterm and low-birth-weight infants, along with her relevant research achievements. In addition, she played a key role in expanding oral check-ups and establishing dental clinical guidelines for infants with rare diseases, further ensuring comprehensive care. These accomplishments have collectively contributed to improving the health outcomes of newborns, thus supporting efforts to increase the healthy birth population in response to the low birth rate.
1. Harnessing the dental cells derived from human induced pluripotent stem cells for hard tissue engineering
The hardest tissues that make up our body are bones and teeth. Professor Jung Han-Sung's research team attempted to differentiate human induced pluripotent stem cells (hiPSCs) in various extracellular matrix (ECM) environments to regenerate these hard tissues. The research team differentiated hiPSCs into two types, dental epithelial cells and dental mesenchymal cells, which form teeth, without using any animal-derived materials, and reported that when the two types of differentiated cells were recombined in GelMA or Collagen environment, they produced bone, and when they were recombined in agar, they produced a bioengineered tooth-like structure. This means that hard tissues, including teeth and bones, can be regenerated using stem cells. This study was published in the international scientific journal in the field of medical science, the "Journal of Advanced Research (impact factor 11.4)" in July 2024.
Eun-Jung Kim, Research Associate Professor, Division in Anatomy and Developmental Biology, Department of Oral Biology, Yonsei University College of Dentistry
Han-Sung Jung, Professor, Division in Anatomy and Developmental Biology, Department of Oral Biology, Yonsei University College of Dentistry
Abstract
Introduction: Most mineralized tissues in our body are present in bones and teeth. Human induced pluripotent stem cells (hiPSCs) are promising candidates for cell therapy to help regenerate bone defects and teeth loss. The extracellular matrix (ECM) is a non-cellular structure secreted by cells. Studies on the dynamic microenvironment of ECM are necessary for stem cell-based therapies.
Objectives: We aim to optimize an effective protocol for hiPSC differentiation into dental cells without utilizing animal-derived factors or cell feeders that can be applied to humans and to mineralize differentiated dental cells into hard tissues.
Methods: For the differentiation of both dental epithelial cells (DECs) and dental mesenchymal cells (DMCs) from hiPSCs, an embryoid body (EB) was formed from hiPSCs. hiPSC were differentiated into neural crest cells with an induction medium utilized in our previous study, and hiPSC-derived DECs were differentiated with a BMP-modulated customized medium. hiPSC-dental cells were then characterized, analyzed, and validated with transcriptomic analysis, western blotting, and RT-qPCR. To form mineralized tissues, hiPSC-derived DECs were recombined with hiPSC-derived DMCs encapsulated in various biomaterials, including gelatin methacryloyl (GelMA), collagen, and agar matrix.
Results: These hiPSC-derived dental cells are highly osteogenic and chondro-osteogenic in photocrosslinkable GelMA hydrogel and collagen type I microenvironments. Furthermore, hiPSC-derived dental cells in agar gel matrix induced the formation of a bioengineered tooth.
Conclusion: Our study provides an approach for applying hiPSCs for hard tissue regeneration, including tooth and bone. This study has immense potential to provide a novel technology for bioengineering organs for various regenerative therapies.
2. Flapless early implant placement into the uncalcified provisional matrix-Does it lead to osseointegration of the implant? A preclinical study
The timing of implant placement after tooth extraction is classified according to the ossification state of the extraction socket. Specifically referring to the molar region, in the past, implants were placed at the point of complete ossification, typically 3 to 4 months after extraction. However, with the recent advancements in materials and the growing emphasis on patient-centered care, implant placement is being scheduled earlier, with trends favoring immediate or early placement.
At the time of early implant placement (4-8 weeks), the extraction socket is filled with uncalcified provisional matrix. This tissue is similar to granulation tissue, which precedes ossification. Over time, it undergoes calcification and becomes bone. However, there has been no research to date on whether osseointegration of the implant will occur if it is placed in this uncalcified provisional matrix.
Through their study, Professor Jung's research team has revealed that implants placed early in this uncalcified provisional matrix can undergo normal healing processes and achieve complete osseointegration.
This study was published in the Journal of Clinical Periodontology (IF= 7.47) in June 2024.
Jin-Young Park, Clinical Assistant Professor, Department of Periodontology, Yonsei University Dental Hospital
Ui-Won Jung, Professor, Department of Periodontology, Yonsei University Dental Hospital
Abstract
Aim: To test whether early implant placement into the extraction socket containing an uncalcified provisional matrix leads to successful osseointegration and stable marginal bone levels.
Materials and Methods: In six mongrel dogs, the mandibular molars were extracted. Three weeks later, early implant placement was performed according to three experimental protocols: (i) flapless implant placement with preservation of the provisional matrix; (ii) flap elevation, socket debridement and implant placement; and (iii) flap elevation, socket debridement, implant placement and guided bone regeneration (GBR). One untreated extraction socket served as a control group. Data analyses were based on histologic slides 3 months after implant placement.
Results: There were no differences in bone-to-implant contact between the three experimental groups (66.97%, 58.89% and 60.89%, respectively) (inter-group comparison p = .42). Marginal bone levels, first bone-to-implant contact as well as the thickness of the connective tissue did not reveal any significant differences between the groups (p = .85, .60 and .65, respectively).
Conclusions: Flapless early implant placement into posterior extraction sockets was as effective as an open flap approach in conjunction with GBR. Mineralization of the socket seems to occur irrespective of the presence of dental implants or biomaterials.
3. Evaluation metric of smile classification by peri-oral tissue segmentation for the automation of digital smile design
The evaluation metric for classifying smiles by segmenting peri-oral tissues plays a key role in enhancing the efficiency of aesthetic dental design automation. Professor Jong-Eun Kim's research team developed an automated smile classification model called the “smile index,” which uses computational methods to numerically classify and analyze conventional smile types. The datasets used in this study consisted of 300 images to verify, 150 images to validate, and 9 images to test the evaluation metric. The classification accuracy reached 0.933, and the F1 score was over 0.9. This research was published in the Journal of Dentistry (Impact Factor: 4.8) in February 2024.
Seulgi Lee, Postdoctoral Researcher, Department of Prosthodontics, Yonsei University College of Dentistry
Gan Jin, Postdoctoral Researcher, Department of Prosthodontics, Yonsei University College of Dentistry
Hoi-In Jung, Associate Professor, Department of Preventive Dentistry and Public Oral Health, Yonsei University College of Dentistry
Jong-Eun Kim, Associate Professor, Department of Prosthodontics, Yonsei University College of Dentistry
Abstract
Objectives: This study aimed to develop and validate evaluation metric for an automated smile classification model termed the “smile index.” This innovative model uses computational methods to numerically classify and analyze conventional smile types.
Methods: The datasets used in this study consisted of 300 images to verify, 150 images to validate, and 9 images to test the evaluation metric. Images were annotated using Labelme. Computational techniques were used to calculate smile index values for the study datasets, and the resulting values were evaluated in three stages.
Results: The smile index successfully classified smile types using cutoff values of 0.0285 and 0.193. High accuracy (0.933) was achieved, along with an F1 score greater than 0.09. The smile index successfully reclassified smiles into six types (low, low-to-medium, medium, medium-to-high, high, and extremely high smiles), thereby providing a clear distinction among different smile characteristics.
Conclusion: The smile index is a novel dimensionless parameter for classifying smile types. The index acts as a robust evaluation tool for artificial intelligence models that automatically classify smile types, thereby providing a scientific basis for largely subjective aesthetic elements.
4. Effect of loupe and microscope on dentists' neck and shoulder muscle workload during crown preparation
Although there is consensus among dentists that visual aids not only improve vision but also help improve posture, evidence is scarce. Conducted together with Department of Rehabilitation Medicine, Gangnam Severance Hospital, Yonsei University, this study recorded dentists’ neck and shoulder muscle workload during crown preparation without any visual aid, using a loupe, and using a microscope. Results revealed that the burden of the studied muscles can successfully be reduced with the use of a loupe or microscope. It is expected that the findings of this study will serve as a reference for future studies striving to find ways to prevent musculoskeletal disorders among dentists. This study was published in the international scientific journal 'Scientific Reports (impact factor 3.8)' in July 2024.
Soohyun Hong, Master's Student, Department of Conservative Dentistry, Gangnam Severance Hospital, Yonsei University College of Dentistry
Jinyoung Park, Clinical Assistant Professor, Department of Rehabilitation Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine
Mi-Jeong Jeon, Clinical Professor, Department of Conservative Dentistry, Gangnam Severance Hospital, Yonsei University College of Dentistry
Su-Jung Shin, Professor, Department of Conservative Dentistry, Gangnam Severance Hospital, Yonsei University College of Dentistry
Jung Hyun Park, Professor, Department of Rehabilitation Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine
Jeong-Won Park, Professor, Department of Conservative Dentistry, Gangnam Severance Hospital, Yonsei University College of Dentistry