1.Evaluation of Surface Hardness and Wear Resistance of a Glass-Hybrid Restorative Material with Nano-filled Resin Coating
Gawon LEE ; Haeni KIM ; Minho HONG ; Juhyun LEE
Journal of Korean Academy of Pediatric Dentistry 2025;52(2):152-158
This study aimed to evaluate the surface hardness and wear resistance of a novel glass-hybrid restorative material in comparison with those of high-viscosity glass ionomer cement (GIC). Additionally, this study examined how the application of a nano-filled resin coating affected these mechanical properties. This study utilized 80 disk-shaped samples prepared from two distinct GI materials: Equia Forte HT Fil and Fuji IX GP. Half of the specimens from each material group were treated with an Equia Forte Coat. Vickers hardness tests were conducted on a set of 40 specimens, and wear resistance was measured on a separate set of 40 specimens. Equia Forte HT Fil showed significantly higher hardness than Fuji IX GP (p < 0.05). The nano-filled resin coating did not significantly affect the hardness in both groups (p > 0.05). In wear depth measurements, uncoated Equia Forte HT Fil showed significantly lower wear depth compared to uncoated Fuji IX GP (p < 0.05). After coating application, both GI groups showed significantly decreased wear depth (p < 0.05). In terms of both hardness and wear resistance, the properties of the glass-hybrid restorative material were superior to those of the high-viscosity GIC. Nano-filled resin coating exhibited no significant positive effect on the hardness of either GI cement material but significantly increased their wear resistance.
2.Evaluation of Surface Hardness and Wear Resistance of a Glass-Hybrid Restorative Material with Nano-filled Resin Coating
Gawon LEE ; Haeni KIM ; Minho HONG ; Juhyun LEE
Journal of Korean Academy of Pediatric Dentistry 2025;52(2):152-158
This study aimed to evaluate the surface hardness and wear resistance of a novel glass-hybrid restorative material in comparison with those of high-viscosity glass ionomer cement (GIC). Additionally, this study examined how the application of a nano-filled resin coating affected these mechanical properties. This study utilized 80 disk-shaped samples prepared from two distinct GI materials: Equia Forte HT Fil and Fuji IX GP. Half of the specimens from each material group were treated with an Equia Forte Coat. Vickers hardness tests were conducted on a set of 40 specimens, and wear resistance was measured on a separate set of 40 specimens. Equia Forte HT Fil showed significantly higher hardness than Fuji IX GP (p < 0.05). The nano-filled resin coating did not significantly affect the hardness in both groups (p > 0.05). In wear depth measurements, uncoated Equia Forte HT Fil showed significantly lower wear depth compared to uncoated Fuji IX GP (p < 0.05). After coating application, both GI groups showed significantly decreased wear depth (p < 0.05). In terms of both hardness and wear resistance, the properties of the glass-hybrid restorative material were superior to those of the high-viscosity GIC. Nano-filled resin coating exhibited no significant positive effect on the hardness of either GI cement material but significantly increased their wear resistance.
3.Evaluation of Surface Hardness and Wear Resistance of a Glass-Hybrid Restorative Material with Nano-filled Resin Coating
Gawon LEE ; Haeni KIM ; Minho HONG ; Juhyun LEE
Journal of Korean Academy of Pediatric Dentistry 2025;52(2):152-158
This study aimed to evaluate the surface hardness and wear resistance of a novel glass-hybrid restorative material in comparison with those of high-viscosity glass ionomer cement (GIC). Additionally, this study examined how the application of a nano-filled resin coating affected these mechanical properties. This study utilized 80 disk-shaped samples prepared from two distinct GI materials: Equia Forte HT Fil and Fuji IX GP. Half of the specimens from each material group were treated with an Equia Forte Coat. Vickers hardness tests were conducted on a set of 40 specimens, and wear resistance was measured on a separate set of 40 specimens. Equia Forte HT Fil showed significantly higher hardness than Fuji IX GP (p < 0.05). The nano-filled resin coating did not significantly affect the hardness in both groups (p > 0.05). In wear depth measurements, uncoated Equia Forte HT Fil showed significantly lower wear depth compared to uncoated Fuji IX GP (p < 0.05). After coating application, both GI groups showed significantly decreased wear depth (p < 0.05). In terms of both hardness and wear resistance, the properties of the glass-hybrid restorative material were superior to those of the high-viscosity GIC. Nano-filled resin coating exhibited no significant positive effect on the hardness of either GI cement material but significantly increased their wear resistance.
4.Potential of Erythrosine-Mediated Photodynamic Therapy as a Cavity Disinfectant: Antibacterial Efficacy and Bonding Ability
Gawon LEE ; Haeni KIM ; Siyoung LEE ; Juhyun LEE
Journal of Korean Academy of Pediatric Dentistry 2024;51(3):290-298
This study aimed to evaluate the antibacterial efficacy of erythrosine-mediated photodynamic therapy (PDT) against Streptococcus mutans (S. mutans) in dentin and its effect on the shear bond strength (SBS) of composite resin to dentin. Eighty extracted human noncarious premolars were used in this study. Forty teeth were used for the antibacterial activity test, while the remaining 40 were used for the SBS test. Both experiments were conducted with 4 experimental groups (n = 10): control (distilled water), sodium hypochlorite (NaOCl, 6%), chlorhexidine (CHX, 0.12%), and erythrosine-mediated PDT. Antibacterial effects were evaluated by counting S. mutans colony-forming units (CFUs). The SBS of composite resins to dentin was measured using a universal testing machine. All treatments (NaOCl, CHX, and PDT) demonstrated statistically significant differences in antibacterial activity compared with the control group (p < 0.05). The antibacterial effects were ranked from strongest to weakest as follows: NaOCl, PDT, and CHX. In the SBS test, the NaOCl group exhibited a statistically significant difference compared with the CHX, PDT, and control groups (p < 0.05), with the lowest bond strength. No statistically significant differences were found among the CHX, PDT, and control groups (p > 0.05). Erythrosine-mediated PDT exhibited significant antibacterial effects against S. mutans, with higher antibacterial activity than CHX but lower than NaOCl. Only NaOCl negatively affected the bond strength of composite resin to dentin. In conclusion, erythrosine-mediated PDT shows potential as a cavity disinfectant due to its significant antibacterial effects against S. mutans and lack of adverse effects on bond strength.
5.Potential of Erythrosine-Mediated Photodynamic Therapy as a Cavity Disinfectant: Antibacterial Efficacy and Bonding Ability
Gawon LEE ; Haeni KIM ; Siyoung LEE ; Juhyun LEE
Journal of Korean Academy of Pediatric Dentistry 2024;51(3):290-298
This study aimed to evaluate the antibacterial efficacy of erythrosine-mediated photodynamic therapy (PDT) against Streptococcus mutans (S. mutans) in dentin and its effect on the shear bond strength (SBS) of composite resin to dentin. Eighty extracted human noncarious premolars were used in this study. Forty teeth were used for the antibacterial activity test, while the remaining 40 were used for the SBS test. Both experiments were conducted with 4 experimental groups (n = 10): control (distilled water), sodium hypochlorite (NaOCl, 6%), chlorhexidine (CHX, 0.12%), and erythrosine-mediated PDT. Antibacterial effects were evaluated by counting S. mutans colony-forming units (CFUs). The SBS of composite resins to dentin was measured using a universal testing machine. All treatments (NaOCl, CHX, and PDT) demonstrated statistically significant differences in antibacterial activity compared with the control group (p < 0.05). The antibacterial effects were ranked from strongest to weakest as follows: NaOCl, PDT, and CHX. In the SBS test, the NaOCl group exhibited a statistically significant difference compared with the CHX, PDT, and control groups (p < 0.05), with the lowest bond strength. No statistically significant differences were found among the CHX, PDT, and control groups (p > 0.05). Erythrosine-mediated PDT exhibited significant antibacterial effects against S. mutans, with higher antibacterial activity than CHX but lower than NaOCl. Only NaOCl negatively affected the bond strength of composite resin to dentin. In conclusion, erythrosine-mediated PDT shows potential as a cavity disinfectant due to its significant antibacterial effects against S. mutans and lack of adverse effects on bond strength.
6.Potential of Erythrosine-Mediated Photodynamic Therapy as a Cavity Disinfectant: Antibacterial Efficacy and Bonding Ability
Gawon LEE ; Haeni KIM ; Siyoung LEE ; Juhyun LEE
Journal of Korean Academy of Pediatric Dentistry 2024;51(3):290-298
This study aimed to evaluate the antibacterial efficacy of erythrosine-mediated photodynamic therapy (PDT) against Streptococcus mutans (S. mutans) in dentin and its effect on the shear bond strength (SBS) of composite resin to dentin. Eighty extracted human noncarious premolars were used in this study. Forty teeth were used for the antibacterial activity test, while the remaining 40 were used for the SBS test. Both experiments were conducted with 4 experimental groups (n = 10): control (distilled water), sodium hypochlorite (NaOCl, 6%), chlorhexidine (CHX, 0.12%), and erythrosine-mediated PDT. Antibacterial effects were evaluated by counting S. mutans colony-forming units (CFUs). The SBS of composite resins to dentin was measured using a universal testing machine. All treatments (NaOCl, CHX, and PDT) demonstrated statistically significant differences in antibacterial activity compared with the control group (p < 0.05). The antibacterial effects were ranked from strongest to weakest as follows: NaOCl, PDT, and CHX. In the SBS test, the NaOCl group exhibited a statistically significant difference compared with the CHX, PDT, and control groups (p < 0.05), with the lowest bond strength. No statistically significant differences were found among the CHX, PDT, and control groups (p > 0.05). Erythrosine-mediated PDT exhibited significant antibacterial effects against S. mutans, with higher antibacterial activity than CHX but lower than NaOCl. Only NaOCl negatively affected the bond strength of composite resin to dentin. In conclusion, erythrosine-mediated PDT shows potential as a cavity disinfectant due to its significant antibacterial effects against S. mutans and lack of adverse effects on bond strength.
7.The Relationship Between Brain Activation for Taking Others’ Perspective and Interoceptive Abilities in Autism Spectrum Disorder: An fMRI Study
Huiyeong JEON ; Ahjeong HUR ; Hoyeon LEE ; Yong-Wook SHIN ; Sang-Ick LEE ; Chul-Jin SHIN ; Siekyeong KIM ; Gawon JU ; Jeonghwan LEE ; Joon Hyung JUNG ; Seungwon CHUNG ; Jung-Woo SON
Journal of the Korean Academy of Child and Adolescent Psychiatry 2024;35(3):197-209
Objectives:
In this functional magnetic resonance imaging study, we aimed to investigate the differences in brain activation between individuals with autism spectrum disorder (ASD) and typically developing (TD) individuals during perspective taking. We also examined the association between brain activation and empathic and interoceptive abilities.
Methods:
During scanning, participants from the ASD (n=17) and TD (n=22) groups were shown pain stimuli and asked to rate the level of the observed pain from both self- and other-perspectives. Empathic abilities, including perspective taking, were measured using an empathic questionnaire, and three dimensions of interoception were assessed: interoceptive accuracy, interoceptive sensibility, and interoceptive trait prediction errors.
Results:
During self-perspective taking, the ASD group exhibited greater activation in the left precuneus than the TD group. During other-perspective taking, relative hyperactivation extended to areas including the right precuneus, right superior frontal gyrus, left caudate nucleus, and left amygdala. Brain activation levels in the right superior frontal gyrus while taking other-perspective were negatively correlated with interoceptive accuracy, and those in the left caudate were negatively correlated with perspective taking ability in the ASD group.
Conclusion
Individuals with ASD show atypical brain activation during perspective taking. Notably, their brain regions associated with stress reactions and escape responses are overactivated when taking other-perspective. This overactivity is related to poor interoceptive accuracy, suggesting that individuals with ASD may experience difficulties with the self-other distinction or atypical embodiment when considering another person’s perspective.
8.The Relationship Between Anger and Suicidality
Jun-Hyuck KIM ; Gawon JU ; Sang Ick LEE ; Chul-Jin SHIN ; Jung-Woo SON ; Siekyeong KIM ; Jeonghwan LEE ; Seungwon CHUNG
Mood and Emotion 2023;21(3):86-94
Background:
This study explored the effect of anger on suicidality by dividing participants into a group with major depressive disorder (MDD) and a non-MDD group, and also investigated whether the anger expression affects suicidality in participants without clinical depression.
Methods:
A total of 1,015 residents responded to anonymous questionnaires in our survey. The survey included scales, such as the Patients Health Questionnaire-9 (PHQ-9), Korean State-Trait Anger Expression Inventory, and Mini-International Neuropsychiatric Interview-Plus. Participants were categorized into the MDD and non-MDD groups or depression group and non-depression group following the PHQ-9 score. Logistic regression analysis was performed to confirm the association between anger and suicidality in the non-MDD and non-MDD groups.
Results:
Anger suppression and higher PHQ-9 appeared as risk factors for suicidality in the non-MDD group. The depression level in the non-MDD group mediates the relationship between anger suppression and suicidality. Higher PHQ-9 was no longer a risk factor and anger suppression remains a risk factor in the non-depression group.
Conclusion
Not only depression evaluation, but also anger evaluation is important when assessing suicidality. Implementing anger management programs for people with high anger suppression can help lower suicidality in Korean society, where negative emotional expression is suppressed.
9.Viral shedding patterns of symptomatic SARS-CoV-2 infections by periods of variant predominance and vaccination status in Gyeonggi Province, Korea
Gawon CHOI ; Ah-Young LIM ; Sojin CHOI ; Kunhee PARK ; Soon Young LEE ; Jong-Hun KIM
Epidemiology and Health 2023;45(1):e2023008-
OBJECTIVES:
We compared the viral cycle threshold (Ct) values of infected patients to better understand viral kinetics by vaccination status during different periods of variant predominance in Gyeonggi Province, Korea.
METHODS:
We obtained case-specific data from the coronavirus disease 2019 (COVID-19) surveillance system, Gyeonggi in-depth epidemiological report system, and Health Insurance Review & Assessment Service from January 2020 to January 2022. We defined periods of variant predominance and explored Ct values by analyzing viral sequencing test results. Using a generalized additive model, we performed a nonlinear regression analysis to determine viral kinetics over time.
RESULTS:
Cases in the Delta variant’s period of predominance had higher viral shedding patterns than cases in other periods. The temporal change of viral shedding did not vary by vaccination status in the Omicron-predominant period, but viral shedding decreased in patients who had completed their third vaccination in the Delta-predominant period. During the Delta-predominant and Omicron-predominant periods, the time from symptom onset to peak viral shedding based on the E gene was approximately 2.4 days (95% confidence interval [CI], 2.2 to 2.5) and 2.1 days (95% CI, 2.0 to 2.1), respectively.
CONCLUSIONS
In one-time tests conducted to diagnose COVID-19 in a large population, although no adjustment for individual characteristics was conducted, it was confirmed that viral shedding differed by the predominant strain and vaccination history. These results show the value of utilizing hundreds of thousands of test data produced at COVID-19 screening test centers.
10.Graph Theoretical Analysis of Brain Structural Connectivity in Patients with Alcohol Dependence
Hyunjung LEE ; Joon Hyung JUNG ; Seungwon CHUNG ; Gawon JU ; Siekyeong KIM ; Jung-Woo SON ; Chul-Jin SHIN ; Sang Ick LEE ; Jeonghwan LEE
Experimental Neurobiology 2023;32(5):362-369
This study aimed to compare brain structural connectivity using graph theory between patients with alcohol dependence and social drinkers. The participants were divided into two groups; the alcohol group (N=23) consisting of patients who had been hospitalized and had abstained from alcohol for at least three months and the control group (N=22) recruited through advertisements and were social drinkers. All participants were evaluated using 3T magnetic resonance imaging. A total of 1000 repeated whole-brain tractographies with random parameters were performed using DSI Studio. Four hundred functionally defined cortical regions of interest (ROIs) were parcellated using FreeSurfer based on the Schaefer Atlas.The ROIs were overlaid on the tractography results to generate 1000 structural connectivity matrices per person, and 1000 matrices were averaged into a single matrix per subject. Graph analysis was performed through igraph R package. Graph measures were compared between the two groups using analysis of covariance, considering the effects of age and smoking pack years. The alcohol group showed lower local efficiency than the control group in the whole-brain (F=5.824, p=0.020), somato-motor (F=5.963, p=0.019), and default mode networks (F=4.422, p=0.042). The alcohol group showed a lower global efficiency (F=5.736, p=0.021) in the control network. The transitivity of the alcohol group in the dorsal attention network was higher than that of the control (F=4.257, p=0.046). Our results imply that structural stability of the whole-brain network is affected in patients with alcohol dependence, which can lead to ineffective information processing in cases of local node failure.

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