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YONSEI UNIVERSITY COLLEGE OF DENTISTRY e-Newsletter 2023-3 / September

YUCD Passed a Stage Evaluation of the 4th BK21 Program, Securing 3 Million Dollars Research Grant

The INNO-Dent Convergence Academy of Yonsei University College of Dentistry has been officially granted continued support from the 4th BK21 program after undergoing its stage evaluation. During this evaluation, research achievements since its selection in 2020 are assessed, and the lowest-performing 30% of teams are eliminated. YUCD has successfully passed this evaluation, ensuring continued funding of 3 million dollars until August 2027.

The BK21 program is a creative talent-fostering program of Korean Ministry of Education, aimed at improving the educational environment and R&D capabilities of graduate schools in Korea. Outstanding graduate schools in similar categories are chosen to receive support for seven years in each phase. YUCD has proved its excellence by obtaining approval throughout all phases since the 1st program in 1999.

According to the stage evaluation, YUCD INNO-Dent Convergence Academy has established appropriate visions aligned with the demands of the contemporary era and has implemented various activities to improve research capabilities. Notably, the participating professors have made significant contributions to the academic community. Since the commencement of the 4th BK21 program, participating professors have published 191 papers, resulting in a 58% increase in the average impact factor. Remarkably, 10% of these papers achieved an impact factor above 10.0, indicating that YUCD has achieved a notable enhancement in research quality as well.

The 1st Yonsei Dental Exhibition Showcased Latest Trends in Digital Dentistry and Artificial Intelligence

The 1st Yonsei Dental Exhibition, held under the theme of "Do-it-Yourself Digital Dentistry" (2023 DIYDX) to celebrate the 30th anniversary of the Continuing Education Center at Yonsei University College of Dentistry, took place successfully on July 16, 2023. This event represented the first university-hosted dental exhibition, providing a comprehensive introduction to the latest trends in the field, including cutting-edge AI equipment.

The 2023 DIYDX comprised the academic conference and dental exhibition. During the conference, YUCD faculties delivered lectures, demonstrations, and hands-on sessions on the topic of 'Do-it-Yourself Digital Dentistry.' At the exhibition, 41 dental companies with 52 booths participated, showcasing cutting-edge technology and dental materials currently used in the field.

With 326 participants registered for the academic conference and over 500 dentists and students visiting the exhibition, the event was a great success. Dean Kee-Joon Lee stated, "While the university's primary role has been educating students, becoming a hub for the research and development of medical devices will also be a significant role for the university from now on."

Yonsei Dentistry “Symbiomer Bioactive Medical Materials for Oral-Gut Axis Project” Obtained 320 Thousand Dollars University Grant

The research project titled "Convergence Research of Symbiomer Bioactive Medical Materials for Oral-Gut Axis," led by Professors Sung-Hwan Choi, Jae-Sung Kwon, and Kee-Joon Lee of Yonsei University College of Dentistry, has been selected as a 2023 IPY Integrated Knowledge Seed Grant Project supported by Yonsei University, securing a $320,000 grant. This newly established IPY Seed Grant Project is intended to activate multidisciplinary convergence research and lead to additional funding sources supported by the government or industry. The project is noteworthy, as only six of all colleges at Yonsei University have been selected. It is expected to contribute immensely to the strengthening Yonsei research capabilities.

750 Thousand Dollars Fund Raised for a Brand-new “YUCD Future Strategic Research Project in Dentistry”

Yonsei University College of Dentistry has initiated a new project titled the "YUCD Future Strategic Research Project in Dentistry." This project is designed to develop a growth model that will set the direction for the next generation of dental research and has secured a fund of $750 thousand for a five-year duration. With this innovative project, our goal is to take a leading position in the strategic research field and secure significant national funding to enhance YUCD's research capacity.

First-Ever Patient-Clinician Shared Decision-Making Study in Dentistry in Korea

A research project titled “Establishment and clinical evaluation of Shared Decision Making protocol for periodontitis-involved tooth based on a Patient Preference Value Prediction Model,” led by Professor Jung-Seok Lee of Yonsei University College of Dentistry, has been selected as a ‘2023 Patient-Clinician Shared Decision-Making Project’ supported by the Ministry of Health and Welfare.

Shared Decision Making is a model that encourages the clinician and patient to cooperate to decide the optimal treatment plan based on the clinician’s professional knowledge and patient’s abundant understanding. Periodontal disease carries substantial nursing care costs and places a significant socioeconomic burden due to the high number of outpatient claims during treatment. In the clinical settings, however, the shared decision-making model that can be used for periodontal disease is yet to be developed. The research team is planning to develop the prediction model based on a patient preference value, education program for clinician and patient, and also the guideline for shared decision-making in dentistry. This study is significant as it marks the first attempt in dentistry.

YUCD Dominates 3rd MINEC Academic Awards in Digital Dentistry Research

The Korean Academy of Dental Science has named Professor Sung-Hwan Choi of the Department of Orthodontics and Professor Kyung Chul Oh of the Department of Prosthodontics as the Grand Prize and Gold Prize winners, respectively, of the 3rd MINEC Academic Award.

The MINEC (Megagen International Network of Education & Clinical Research) Academic Award aims to promote research activities in digital dentistry in Korea. It is awarded to young researchers under the age of 45 with outstanding research achievements. This year, both the Grand and Gold Prizes were awarded to faculty members from YUCD, showcasing the research capabilities of the institution.

1. Unraveling the Missing Link of Bio-Electrical Stimulation from Body-Mediated Energy Transfer

Electrical stimulation technology non-invasively stimulates cells and is used to treat nerves in the brain and other nerves. It has the advantage of reducing patient burden, but it is also inconvenient because it requires batteries or wires to continuously produce electricity.

To solve these shortcomings, the research team focused on the characteristic that the human body has a high dielectric constant through which electromagnetic fields are transmitted.

We developed a body-mediated energy transfer (BmET) system to transfer electrical energy generated in daily life to target areas. The research team secured the optimal electric field strength to stimulate cells based on measurements through in vitro tests. After delivering this to osteoblasts and analyzing phenomena such as cell proliferation, growth factor, and protein expression, it was discovered that cell proliferation increased by about 20% due to electrical stimulation. Growth factors and proteins were also confirmed to increase by more than 20% compared to the control group. Through genetic analysis, it was revealed that the expression of genetic markers involved in various cell functions increased by up to 40%. This research outcome was published in the September issue of Advanced Functional Materials (IF 19.0), the most prestigious academic journal in the materials engineering field.

Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry

Abstract

As the technologies for treating diseases are attracting continuous attention, physical therapy methods, particularly electrical stimulation (ES), have been widely investigated owing to their high effectiveness. As ES essentially requires an external power source, various efforts are being devoted to achieving the application of ES to the human body using nanogenerators. Various studies have verified the effect of ES by applying the same output generated by the device to in vitro and in vivo bio-electrical stimulation. However, it is unknown whether the electrical output generated by the device can be transmitted equally in the cell unit, and this is considered a common missing link in bio-electrical stimulation research. Herein, the missing link between electrical devices and in vitro bio-electrical stimulations is unraveled by the ex vivo, 2D simulation, and in vitro study of body-mediated energy transfer (BmET) models. In addition, BmET-based ES is applied to pre-osteoblasts, and the increased cellular functions are verified.

Summary of the study

2. Mitochondria-derived peptide SHLP2 regulates energy homeostasis through the activation of hypothalamic neurons

Extensive research is underway to explore treatment approaches for metabolic disorders such as obesity and type 2 diabetes, yet the underlying causes remain unclear. The research team of Professor Ki Woo Kim of Yonsei University College of Dentistry revealed that Small humanin-like peptide 2 (SHLP2), a mitochondrial-derived peptide, influences metabolic improvements through the activation of pro-opiomelanocortin (POMC) neurons in the arcuate nucleus of the hypothalamus. This study not only reveals the therapeutic potential of SHLP2 in metabolic disorders but also provides important mechanistic insights into how it exerts its effects on energy homeostasis. The study was published in the scientific journal 'Nature Communications' (impact factor 16.6) in July 2023.

Division of Physiology, Department of Oral Biology, Yonsei University College of Dentistry

Abstract

Small humanin-like peptide 2 (SHLP2) is a mitochondrial-derived peptide implicated in several biological processes such as aging and oxidative stress. However, its functional role in the regulation of energy homeostasis remains unclear, and its corresponding receptor is not identified. Hereby, we demonstrate that both systemic and intracerebroventricular (ICV) administrations of SHLP2 protected the male mice from high-fat diet (HFD)-induced obesity and improved insulin sensitivity. In addition, the activation of pro-opiomelanocortin (POMC) neurons by SHLP2 in the arcuate nucleus of the hypothalamus (ARC) is involved in the suppression of food intake and the promotion of thermogenesis. Through high-throughput structural complementation screening, we discovered that SHLP2 binds to and activates chemokine receptor 7 (CXCR7). Taken together, our study not only reveals the therapeutic potential of SHLP2 in metabolic disorders but also provides important mechanistic insights into how it exerts its effects on energy homeostasis.

Summary of the study

3. Ahnak is required to balance calcium ion homeostasis and smooth muscle development in the urinary system

This study demonstrates that Ahnak is widely localized in the kidney and ureter during development and is involved in ion channel activity, transmembrane transporter activ¬ity, cellular calcium ion homeostasis in the kidney, and muscle development, muscle contraction, and calcium ion homeostasis in the ureter. In addition, authors confirmed that the development of hydronephrosis and hydroureter in Ahnak KO mice was caused by failure to regulate calcium homeostasis and smooth muscle function, revealing that Ahnak is essential for the development of the normal renal system. The findings of this study were released in June 2023 in the international medical journal Cell & Bioscience (impact factor 7.5).

Jong-Min Lee: BK21 INNO-Dent Convergence Academy, Yonsei University College of Dentistry

Han-Sung Jung: Division in Anatomy and Developmental Biology, Department of Oral Biology, Yonsei University College of Dentistry

Abstract

Background

Various renal abnormalities, including hydronephrosis, polycystic kidney disease, and hydroureter, have been reported, and these abnormalities are present in DiGeorge syndrome, renal dysplasia, and acute kidney failure. Previous studies have shown that various genes are associated with renal abnormalities. However, the major target genes of nonobstructive hydronephrosis have not yet been elucidated.

Results

We examined neuroblast differentiation-associated protein Ahnak localization and analyzed morphogenesis in developing kidney and ureter. To investigated function of Ahnak, RNA-sequencing and calcium imaging were performed in wild type and Ahnak knockout (KO) mice. Ahnak localization was confirmed in the developing mouse kidneys and ureter. An imbalance of calcium homeostasis and hydronephrosis, which involves an expanded renal pelvis and hydroureter, was observed in Ahnak KO mice. Gene Ontology enrichment analysis on RNA-seq results indicated that ‘Channel Activity’, ‘Passive Transmembrane Transporter Activity’ and ‘Cellular Calcium Ion Homeostasis’ were downregulated in Ahnak KO kidney. ‘Muscle Tissue Development’, ‘Muscle Contraction’, and ‘Cellular Calcium Ion Homeostasis’ were downregulated in Ahnak KO ureter. Moreover, peristaltic movement of smooth muscle in the ureter was reduced in Ahnak KO mice.

Conclusions

Abnormal calcium homeostasis causes renal disease and is regulated by calcium channels. In this study, we focused on Ahnak, which regulates calcium homeostasis in several organs. Our results indicate that Ahnak plays a pivotal role in kidney and ureter development, and in maintaining the function of the urinary system.

Alteration of ureter markers and calcium imaging in Ahnak KO mice at PN1
Summary of the study

4. Effect of airborne particle abrasion treatment of two types of 3D-printing resin materials for permanent restoration materials on flexural strength

Due to the rapid development of digital technology, 3D printing resin materials for final restorations are now being introduced. One essential aspect in proving the clinical efficacy and safety of these new materials is the evaluation of their mechanical properties. Professor Kim's research team has demonstrated that there are differences in mechanical properties based on the composition of two representative types of 3D printing resin materials for final restorations. After Airborne Particle Abrasion (APA) treatment, commonly used in clinical practice, Urethane Dimethacrylate Oligomer (UDMA) resin materials exhibited higher flexural strength compared to Ethoxylated Bisphenol-A Dimethacrylate (BEMA) resin materials. Analyzing the material's behavior through Nano-indentation and Dynamic Mechanical Analysis (DMA), it was reported that UDMA resin materials remained stable even when experiencing significant instantaneous deformation, demonstrating lower strain and higher recovery rates under the same external forces compared to BEMA resin materials. Observations of surface changes after APA treatment revealed that BEMA resin materials developed irregular surface defects compared to UDMA resin materials. In this study, various methods were applied to evaluate the mechanical properties of 3D printing resin materials for restorations, providing insights into the current state of these materials and future directions for their development. This research outcome was published in the international dental science journal 'Dental Materials' in May 2023, with an impact factor of 5.687.

Department of Prosthodontics, Oral Science Research Center, Yonsei University College of Dentistry

Abstract

Objectives

This study aimed to assess the effects of airborne-particle abrasion (APA) on the flexural strength of two types of 3D-printing resins for permanent restoration.

Methods

Two types of 3D printing resins (urethane dimethacrylate oligomer; UDMA, ethoxylated bisphenol-A dimethacrylate; BEMA) constituting different components were printed. The specimen surfaces were subjected to APA using 50 and 110 µm alumina particles under different pressures. The three-point flexural strength was measured for each surface treatment group, and a Weibull analysis was performed. Surface characteristics were analyzed via surface roughness measurements and scanning electron microscopy. Dynamic mechanical analysis and nano-indentation measurements were limited to the control group.

Results

The three-point flexural strength according to the surface treatment was significantly lower in the UDMA group for large particle sizes and at high pressures; the BEMA group demonstrated low flexural strength for large particle sizes regardless of the pressure. After thermocycling, the flexural strengths of UDMA and BEMA significantly decreased in the group subjected to surface treatment. The Weibull modulus and characteristic strength of UDMA were higher than those of BEMA under different APA and thermocycling conditions. As the abrasion pressure and particle size increased, a porous surface formed, and the surface roughness increased. Compared with BEMA, UDMA featured a lower strain, greater strain recovery, and a negligible increase in modulus according to strain.

Significance

Thus, surface roughness increased with the sandblasting particle size and pressure of the 3D-printing resin. Hence, a suitable surface treatment method to improve adhesion can be determined by considering physical property changes.

Representative SEM images and 3D surface profiles of the surface images of two resin materials according to various surface treatments: (A) UDMA; (B) BEMA