Yun-Chan Hwang

Ran-Yi Jin, Dong-Hyun Lee, Kkot-Byeol Bae, Bin-Na Lee, Yun-Chan Hwang. J Dent Rehabil Appl Sci 2026;42:278-85. https://doi.org/10.14368/jdras.2026.42.3.278

Kkot-Byeol Bae, Tae-geon Kim, Su-Jung Park, Yun-Chan Hwang, In-Nam Hwang. J Dent Rehabil Appl Sci 2026;42:90-101. https://doi.org/10.14368/jdras.2026.42.2.90

Kkot-Byeol Bae, Young-Tae Cho, Bin-Na Lee, Hoon-Sang Chang, Yun-Chan Hwang, In-Nam Hwang. J Dent Rehabil Appl Sci 2026;42:79-89. https://doi.org/10.14368/jdras.2026.42.2.79

Pathological root resorption is mediated by odontoclasts, which share functional characteristics with osteoclasts. However, the effect of amelogenin-derived peptide-5 (ADP-5) on osteoclast differentiation remains unclear. Objective This study aimed to determine whether ADP-5 inhibits the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation and to explain the involvement of adenosine monophosphate-activated protein kinase (AMPK). Methodology Bone marrow-derived macrophages were isolated from six-week-old mice from the Institute of Cancer Research. Cell viability was assessed. Osteoclast differentiation was induced with RANKL (100 ng/mL) and macrophage colony-stimulating factor (30 ng/mL) in the presence of ADP-5 (0–20 μM). Multinucleated cells were quantified by tartrate-resistant acid phosphatase (TRAP) staining. Osteoclast-specific marker expression (cellular proto-oncogene Fos, cathepsin K, nuclear factor of activated T-cells cytoplasmic 1, and TRAP) was analyzed via quantitative real-time polymerase chain reaction and Western blot. Bone resorption activity was evaluated using a calcium phosphate-coated pit assay. AMPK phosphorylation was examined to assess the associated signaling pathway. Results ADP-5 showed no effect on cell viability. It reduced TRAP-positive multinucleated cell formation and the mRNA and protein expression of key osteoclastogenic markers. Resorptive activity was significantly reduced in ADP-5-treated cells. In parallel, ADP-5 enhanced AMPK phosphorylation during differentiation. Conclusions ADP-5 suppressed RANKL-induced osteoclastogenesis and resorptive activity and was associated with enhanced AMPK phosphorylation. These findings identify ADP-5 as a potential modulator of RANKL-induced osteoclastogenesis and provide a rationale for further investigation of its effects and underlying mechanisms in inflammatory root resorption models.

Objectives: This study aimed to analyze the temperature changes during the light curing of conventional flowable composite resin and bulk-fill composite resin of various thicknesses using an infrared thermographic camera.Methods: Flowable composite resin (G-aenial Flo, GC Co.) and bulk-fill composite resin (SDR, Dentsply Caulk) were used. Specimens with thicknesses from 0.5 mm to 5.0 mm were prepared. The infrared thermographic camera measured the temperature changes at the maximum temperature rise point during light curing. The data were analyzed for maximum temperature, time to peak temperature, and temperature rise patterns.Results: For G-aenial Flo, the maximum temperature tended to decrease with increasing thickness, whereas for SDR, the maximum temperature decreased up to 2.0 mm and then remained relatively consistent from 2.0 mm to 5.0 mm. At thicknesses of 1.5 mm or less, both resins showed a rapid temperature increase within the first 5 seconds, followed by a reduced rate of increase up to 80 seconds. At thicknesses of 2.0 mm or greater, the temperature peaked and then gradually decreased. Across all thicknesses, SDR was observed to reach peak temperature more rapidly than G-aenial Flo.Conclusions: Observable differences in polymerization dynamics were identified between the two resin types, particularly at greater thicknesses. Although no statistical analysis was performed, these descriptive findings suggest that infrared thermographic cameras may be useful for indirectly assessing polymerization dynamics during resin polymerization.

Hye-Yun Koo, Ji-soo Kim, Yun-Chan Hwang, Bin-Na Lee. J Dent Rehabil Appl Sci 2025;41:209-16. https://doi.org/10.14368/jdras.2025.41.3.209

Min-Jeong Ko, Kkot-Byeol Bae, Yun-Chan Hwang, Bin-Na Lee, Won-Mann Oh. J Dent Rehabil Appl Sci 2025;41:150-6. https://doi.org/10.14368/jdras.2025.41.2.150

Hye-Yun Koo, Bin-Na Lee, Yun-Chan Hwang. J Dent Rehabil Appl Sci 2025;41:140-9. https://doi.org/10.14368/jdras.2025.41.2.140

Objectives: This study aimed to evaluate the stress distribution in teeth restored with different post materials and bonding conditions using finite element analysis (FEA).Methods: A two-dimensional FEA model of a maxillary central incisor restored with IPS-Empress-2 crown (Ivoclar Vivadent), composite resin core, and posts were created. The model simulated bonded and non-bonded conditions for both fiber-reinforced composite (FRC) and titanium (Ti) posts. Stress distribution was analyzed using ANSYS 14.0 software under a 100-N load applied at a 45° angle to the long axis of the tooth.Results: The results revealed that stress concentration was significantly higher in non-bonded posts compared to bonded ones. FRC posts exhibited stress values closer to those of dentin, whereas Ti posts demonstrated higher stress concentration, particularly in non-bonded states, increasing the potential risk of damage to surrounding tissues.Conclusions: FRC posts, with elastic properties similar to dentin and proper adhesion, minimize stress concentration and potential damage to surrounding tissues. Conversely, materials with higher elastic modulus like Ti, can cause unfavorable stress concentrations if not properly bonded, emphasizing the importance of post adhesion in tooth restoration.

Ji-Soo Kim, Kkot-Byeol Bae, Yun-Chan Hwang, Won-Mann Oh, Bin-Na Lee. J Dent Rehabil Appl Sci 2024;40:31-8. https://doi.org/10.14368/jdras.2024.40.1.31