New Leap Forward for a Global Education Institute
From October 29 to 31, 2024, the Commission on Dental Accreditation (CODA) visited Yonsei University College of Dentistry (YUCD) for a special focused preliminary accreditation consultation visit. CODA is a sole agency recognized by the United States Department of Education to accredit dental education programs. During the visit, CODA site visit team, consisting of two onsite members and one online member, thoroughly reviewed education programs and patient care services and conducted interviews with faculty members and dental students.
YUCD has been preparing for the accreditation to align with global standards for dental education since 2008. This preparation process itself has brought innovations, including curriculum and practice course reforms, intensified faculty and student competency levels, and upgrades in educational infrastructure and research facilities. Getting accreditation will inspire us to reach new heights of excellence in education quality. Furthermore, it will provide students with greater opportunities on a global platform. If accreditation is successfully granted, YUCD will become the first institution in South Korea to earn this privilege.
Yonsei University College of Dentistry Designated as ITI Scholarship Center
Yonsei University College of Dentistry has been designated as an ITI Scholarship Center under the leadership of Prof. Ui-Won Jung from the Department of Periodontics. The International Team for Implantology (ITI), headquartered in Basel, Switzerland, is the largest global non-profit academic association of professionals in implant dentistry, with 25 thousand members. ITI conducts various conferences and educational projects to support the development of evidence-based dental medicine.
As a part of its mission, ITI selects Scholarship Centers to foster and educate scholars annually. Selected students are given the opportunity to have yearlong training at one of these centers. Being designated as an ITI Scholarship Center requires international recognition for both education and clinical practice.
Prof. Jung, who completed ITI scholarship training at the University of Zurich in 2007, now serves as the academic director of ITI Korea. His leadership has played a pivotal role in achieving this prestigious designation for YUCD.
2024 SYMPOSIUM YUCM-YUCD-KUCM-NIPS: Exploring Future Pathways
The 2024 SYMPOSIUM YUCM-YUCD-KUCM-NIPS was held from November 21 to 22, 2024. Yonsei University College of Dentistry, Yonsei University College of Medicine (YUCM), Korea University College of Medicine (KUCM), and the National Institute for Physiological Sciences (NIPS), Japan have been engaged in a collaborative partnership for 24 years, following the signing of an agreement on joint research and education cooperation in 2001.
This year marked the 8th symposium, organized by Yonsei University and hosted by the YUCD BK21 Project of the INNO-Dent Convergence Academy and the Center for Convergence Research on Taste-Oral Functions.
The symposium featured three main sessions: the Regular Session, the Young Scientist Session, and the Poster Session. It served as a platform for sharing the latest research trends and achievements in various fields of medical life sciences. Over 170 participants, including faculty members, young researchers, and graduate students, attended the event. Among them were two chairs, seven speakers, and ten poster presenters representing YUCD.
The symposium is expected to serve as a foundation for building future-oriented collaborative research relationships between Korean and Japanese basic medical scientists.
Advancing Multidisciplinary Research: 23rd Yonsei Dental International Symposium
The 23rd Yonsei Dental International Symposium took place on December 6, 2024, beginning with the Dean Young-Soo Jung’s welcome speech. The event featured a Joint Symposium of the Colleges of Dentistry, Engineering, and Medicine, along with an Academic Poster Presentation. This year, the College of Medicine participated for the first time, providing an opportunity to expand multidisciplinary research collaborations for the advancement of medical science.
Under the theme ‘Artificial Intelligence (AI) for Medical Innovation: Conversion Impact,’ six speakers from three colleges delivered a presentation, with over 100 faculty members and researchers in attendance. In the poster presentation session, 87 researchers and graduate students shared their research reviews in 9 sections, among which 9 were recognized with best presentation awards.
As the Ministry of Science and ICT announced that 2025 R&D investments will focus on three key technologies—AI semiconductors, advanced bio, and quantum— YUCD is planning to lead the future medical sciences by supporting collaborative research across dentistry, engineering, and medicine.
1. Viscoelastic and antimicrobial dental care bioplastic with recyclable life cycle
Presently, clear aligners are predominantly made of polyethylene terephthalate glycol (PETG), which offers superior aesthetics. However, these devices present practical and environmental limitations, as approximately 100–120 appliances are required per patient during treatment, with each appliance discarded after approximately one week of use.
To address these challenges, a research team led by Professor Sung-Hwan Choi of the Department of Orthodontics at Yonsei University College of Dentistry developed an eco-friendly bioplastic derived from silk fibroin extracted from silkworm cocoons. This bioplastic was applied as clear orthodontic appliance, and its functionality was validated through animal testing.
The newly developed bioplastic exhibited a 55.7% effective tooth movement force delivery compared to conventional PETG materials. Furthermore, it demonstrated significant antimicrobial properties, reducing Streptococcus mutans, a major cariogenic bacterium, by 80%, and decreasing the prevalence of Veillonella atypica and Enterococcus faecalis, key bacterial species in dental biofilm, by over 90%. Additionally, the researchers confirmed that up to 72% of the used silk fibroin could be re-extracted to fabricate new orthodontic appliance, enhancing the material’s sustainability.
This study shows that silk fibroin-based bioplastics overcome existing material limitations, providing an eco-friendly, functional alternative for clear orthodontic appliances. Published in Nature Communications (IF 14.6; JCR top 5.6%) in October 2024, it highlights a promising solution for improved sustainability and treatment efficiency. in the field of clear orthodontic devices.
Sung-Hwan Choi, Associate Professor, Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry
Utkarsh Mangal, Research Assistant Professor, BK21 Four Inno-Dent Convergence Academy, Yonsei University College of Dentistry
Jung-Yul Cha, Professor, Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry
Kee-Joon Lee, Professor, Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry
Abstract
Medical plastic-appliance-based healthcare services, especially in dentistry, generate tremendous amounts of plastic waste. Given the physiological features of our mouth, it is desirable to substitute dental care plastics with viscoelastic and antimicrobial bioplastics. Herein, we develop a medical-grade and sustainable bioplastic that is viscoelastic enough to align the tooth positions, resists microbial contamination, and exhibits recyclable life cycles. In particular, we devise a molecular template involving entanglement-inducing and antimicrobial groups and prepare a silk fibroin-based dental care bioplastic. The generated compactly entangled structure endows great flexibility, toughness, and viscoelasticity. Therefore, a satisfactory orthodontic outcome is accomplished, as demonstrated by the progressive alignment of male rabbit incisors within the 2.5 mm range. Moreover, the prepared bioplastic exhibits resistance to pathogenic colonization of intraoral microbes such as Streptococcaceae and Veillonellaceae. Because the disentanglement of entangled domains enables selective separation and extraction of the components, the bioplastic can be recycled into a mechanically identical one. The proposed medical-grade and sustainable bioplastic could potentially contribute to a green healthcare future.
2. Implementing microfluidic flow device model in utilizing dural substitutes as pulp capping materials for vital pulp therapy
Mineral trioxide aggregate (MTA) is one of the most commonly used materials for pulpotomy. However, recent reports from long-term follow-up studies have highlighted challenges in retreatment due to excessive root canal calcification in patients who underwent this procedure. A research team led by Professor Su-Jung Shin, Sun-Il Kim, and Jae-Sung Kwon investigated methods to prevent pulp calcification while promoting its recovery. They focused on a key structural similarity between tooth and cranium, wherein hard tissue encases soft tissue. In case of increased intracranial pressure caused by inflammation, decompression using dural substitutes has been shown to facilitate brain recovery through conservative means. Inspired by this concept, the team explored the possibility of applying such technology to pulpotomy. They fabricated a microfluidic flow chip simulating the dental pulp environment to compare the effects of a dural substitutes with MTA. Compared to MTA, the dural substitutes demonstrated superior elasticity, allowing it to expand under pressure, making it advantageous for decompression. Additionally, it effectively blocked the infiltration of monomers and other substances, thereby protecting pulp vitality. This material also maintained the intrinsic properties of dental pulp stem cells and vascular endothelial cells preventing excessive calcification. Consequently, the study demonstrated the potential of dural substitutes as a viable alternative for pulpotomy. The findings from this research were published in the international journal Biofabrication (impact factor 8.2) in August 2024.
Min-Yong Lee, Basic Science Resident, Department and Research Institute of Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry
Hi-Won Yoon, Resident, Department of Conservative Dentistry and Oral Science Research Center, Gangnam Severance Hospital, Yonsei University College of Dentistry
Sun-Il Kim, Associate Professor, Department of Conservative Dentistry and Oral Science Research Center, Yonsei University College of Dentistry
Jae-Sung Kwon, Assistant Professor, Department and Research Institute of Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry
Su-Jung Shin, Professor, Department of Conservative Dentistry and Oral Science Research Center, Gangnam Severance Hospital, Yonsei University College of Dentistry
Abstract
Vital pulp therapy (VPT) has gained prominence with the increasing trends towards conservative dental treatment with specific indications for preserving tooth vitality by selectively removing the inflamed tissue instead of the entire dental pulp. Although VPT has shown high success rates in long-term follow-up, adverse effects have been reported due to the calcification of tooth canals by mineral trioxide aggregates (MTAs), which are commonly used in VPT. Canal calcification poses challenges for accessing instruments during retreatment procedures. To address this issue, this study evaluated the mechanical properties of dural substitute intended to alleviate intra-pulp pressure caused by inflammation, along with assessing the biological responses of human dental pulp stem cells (hDPSCs) and human umbilical vein endothelial cells (HUVECs), both of which play crucial roles in dental pulp. The study examined the application of dural substitutes as pulp capping materials, replacing MTA. This assessment was conducted using a microfluidic flow device model that replicated the blood flow environment within the dental pulp. Computational fluid dynamics simulations were employed to ensure that the fluid flow velocity within the microfluidic flow device matched the actual blood flow velocity within the dental pulp. Furthermore, the dural substitutes (Biodesign; BD and Neuro-Patch; NP) exhibited resistance to penetration by 2-hydroxypropyl methacrylate (HEMA) released from the upper restorative materials and bonding agents. Finally, while MTA increased the expression of angiogenesis-related and hard tissue-related genes in HUVEC and hDPSCS, respectively, BD and NP did not alter gene expression and preserved the original characteristics of both cell types. Hence, dural substitutes have emerged as promising alternatives for VPT owing to their resistance to HEMA penetration and the maintenance of stemness. Moreover, the microfluidic flow device model closely replicated the cellular responses observed in live pulp chambers, thereby indicating its potential use as anin vivotesting platform.
3. Quantitative assessment of early caries lesion activity using novel dye-enhanced fluorescence imaging
Accurate assessment of caries lesion activity in early dental caries is critical for providing appropriate preventive treatment and effective management. However, conventional visual-tactile methods used to evaluate lesion activity have limitations in reliability due to examiner subjectivity and varying levels of clinical experience. Professor Baek-Il Kim's research team has demonstrated that a novel method, Dye-Enhanced Quantitative Light-Induced Fluorescence (DEQLF), can objectively and quantitatively assess the activity status of early caries lesions by integrating fluorescent dye application with existing QLF technology. The DEQLF technique involves applying a fluorescent dye for 10 seconds, followed by QLF imaging to observe fluorescence changes. The study found that, when DEQLF was applied, active lesions with higher surface porosity exhibited significantly greater fluorescence changes due to deeper and more extensive dye penetration compared to inactive lesions. This result indicates that DEQLF can effectively assess lesion surface porosity based on dye penetration patterns, enabling immediate and accurate evaluation of early caries lesions. This advancement establishes a new standard for the prevention and management of dental caries. This study was published in September 2024 in Journal of Dentistry (impact factor 4.8), one of the leading international journals in the field of dentistry.
Eun-Song Lee, Research Assistant Professor, Department of Preventive Dentistry & Public Oral Health, BK21 FOUR Project, Yonsei University College of Dentistry
Baek-Il Kim, Professor, Department of Preventive Dentistry & Public Oral Health, BK21 FOUR Project, Yonsei University College of Dentistry
Abstract
Objectives: This study aimed to evaluate the validity of the dye-enhanced quantitative light-induced fluorescence (DEQLF) method for assessing early enamel caries activity.
Methods: Seventy extracted human teeth with early enamel caries on smooth surfaces were included. Two dentists evaluated the caries activity using the Nyvad system followed by the DEQLF method. The teeth were hydrated with distilled water for 60 s, dehydrated with compressed air for 10 s, and stained with 100 μM fluorescein sodium solution for 10 s. White and fluorescent images were captured using a QLF-D 2+ Billuminator. The change in fluorescence (ΔΔG) was calculated using image analysis software. Independent-sample t-tests were performed to evaluate the difference in ΔΔG between active and inactive lesions for both DEQLF and conventional quantitative light-induced fluorescence (QLF) methods. Receiver operating characteristic (ROC) curve analysis was used to assess the validity of ΔΔG for distinguishing lesion activity using the area under the ROC curve (AUROC).
Results: Among the 70 caries lesions, 33 were active and 37 were inactive. Using the DEQLF method, the ΔΔG for active lesions (3.8 ± 5.6) was significantly higher than that for inactive lesions (1.0 ± 2.5) (P < 0.05). With the conventional QLF method, there was no significant difference in ΔΔG between active (-1.1 ± 1.7) and inactive (-1.3 ± 1.7) lesions. DEQLF-derived ΔΔG demonstrated an AUROC of 0.72, a sensitivity of 0.67, and a specificity of 0.76.
Conclusions: Applying the DEQLF method to human teeth enabled the quantitative assessment of lesion activity based on dye penetration. DEQLF-derived ΔΔG values showed significant differences based on lesion activity status and demonstrated high validity in distinguishing lesion activity.
Clinical significance: Clinicians can use the DEQLF method, which involves applying a fluorescent dye for 10 s prior to conventional QLF, to objectively quantify and distinguish the activity status of early enamel caries, potentially replacing the traditional reliance on subjective visual assessments.
4. Mechanical properties and crown accuracy of additively manufactured zirconia restorations
In dentistry, zirconia is known for its superior physical strength, biocompatibility, and masking ability compared with conventional ceramics. The application of zirconia as a restorative material has seen significant growth in recent years, largely driven by advancements in CAD/CAM technology. The advent of 3D printing technology has led to endeavors to utilize additive manufacturing techniques for the fabrication of zirconia ceramic restorations. The objective of this study was to comparatively analyze the mechanical properties of zirconia restorations produced via additive manufacturing and the crown accuracy of zirconia crowns. The findings of this study suggest that additively produced zirconia restorations have mechanical properties comparable to those of conventionally produced ceramics and may be suitable for clinical applications.
Sae-Eun Oh, PhD Student, Department of Prosthodontics, Yonsei University College of Dentistry
Young-Bum Park, Professor, Department of Prosthodontics, Yonsei University College of Dentistry
Abstract
Objectives: We evaluated the mechanical properties of zirconia restorations produced via additive manufacturing (AM) and the crown accuracy of zirconia crowns.
Methods: Zirconia disks, bars, and crowns were manufactured via subtractive (CNC group) and additive manufacturing (AM group) techniques. Disk-shaped specimens in each group were autoclaved at 134 °C and 216 kPa for 5, 10, and 24 h. The phases of the specimens were analyzed using an X-ray diffractometer. The flexural strengths were measured via biaxial flexural tests. The morphologies were examined using a scanning electron microscope. The correlation between the m-phase fraction and biaxial flexural strength by autoclave time in each group was analyzed via linear mixed model and Pearson's correlation analysis. For each group, crown specimens were used to assess the marginal and internal gaps using the replica technique. Buccolingual and mesiodistal cross-sections were measured, and a repeated measures one-way ANOVA was performed.
Results: Linear mixed model analysis indicated that for both groups, with an increase in the autoclave time, the flexural strength decreased, whereas the m-phase fraction increased. Pearson's correlation analysis revealed no correlation between the m-phase fraction and flexural strength for either group. A repeated measures one-way ANOVA was conducted on instrumented sections (buccal, lingual, mesial, and distal), revealing that the marginal and internal gaps of AM-produced zirconia crowns were less accurate than those of CNC-produced zirconia crowns.
Significance: These findings suggest that additively produced zirconia restorations have mechanical properties comparable to those of conventionally produced ceramics and may be suitable for clinical applications.
Credits:
Yonsei University College of Dentistry