1.Effects of clear aligner edentulous space design on distal canine movement: An iterative finite element analysis in cases involving extraction
Seung Eun BAEK ; Kiyean KIM ; Youn-Kyung CHOI ; Sung-Hun KIM ; Seong-Sik KIM ; Ki Beom KIM ; Yong-Il KIM
The Korean Journal of Orthodontics 2025;55(3):193-201
Objective:
Using finite element method (FEM) analysis of a clear aligner (CA), this study aimed to investigate the effects of varying the edentulous space on canine distal bodily movement during space closure following maxillary first premolar extraction.
Methods:
FEM analysis was used to simulate distal canine bodily movement following maxillary first premolar extraction using CAs. Four CA designs for edentulous spaces were compared: no-pontic, full-pontic, halfpontic, and beam. Three-dimensional models of the tooth components and CA were created. The target was set at a 0.25-mm distal canine movement. Long-term tooth movement was simulated using an iterative calculation method.
Results:
All the groups initially showed crown displacement, distal tipping, and distal rotation.Over time, the movement patterns differed in relation to the design. The no-pontic design exhibited the greatest displacement and tipping. The beam design exhibited the largest initial displacement but showed the lowest displacement and tipping thereafter. Full- and half-pontic designs yielded intermediate results. Significant force reduction was observed immediately after CA application, and was followed by a gradual decrease. The mean tooth-movement achievement rate was approximately 76.7%.
Conclusions
The edentulous space design of the CA substantially affected tooth-movement behavior. An iterative simulation is necessary to evaluate longterm tooth-movement patterns. The beam design demonstrated optimal suitability for bodily movement with minimal tipping. For optimal results, additional setup or overcorrection may be necessary.
2.Force and moment analysis of clear aligners: Impact of material properties and design on premolar rotation
Dong-Woo KIM ; Hyun-Jun LEE ; Ki Beom KIM ; Sung-Hun KIM ; Seong-Sik KIM ; Soo-Byung PARK ; Youn-Kyung CHOI ; Yong-Il KIM
The Korean Journal of Orthodontics 2025;55(3):212-223
Objective:
To quantitatively analyze and compare the forces and moments generated by thermoformed polyethylene terephthalate glycol (PETG) and direct-printed TC-85 clear aligners (CAs), with various margin designs, during premolar rotation.
Methods:
In total, 132 CAs were fabricated and divided into four groups (n = 33 per group). Group C consisted of thermoformed PETG aligners with a 2 mm gingival margin. Group E comprised direct-printed TC-85 aligners with equi-gingival margin, whereas Group G utilized direct-printed TC-85 aligners with 2 mm gingival margins.Finally, Group T featured direct-printed TC-85 aligners with an additional 1 mm thickness at the mesial embrasure. The forces and moments were measured using a 6-axis force/moment transducer at 2°, 3°, and 4° of rotation. All measurements were conducted at 37°C to simulate intraoral conditions. Forces were measured in the buccolingual, anteroposterior, and vertical directions, while moments were measured in the mesiodistal, buccolingual, and rotational planes.
Results:
The PETG aligners (Group C) showed significantly increased buccal and posterior force across the rotation angles (P < 0.05), whereas the intrusive force remained consistent. In contrast, the TC-85 aligners maintained consistent forces across all rotation angles.Direct-printed aligners demonstrated significantly lower intrusive forces than PETG aligners (P < 0.001). Group T exhibited reduced unwanted forces while maintaining effective rotational moments. Furthermore, all direct-printed aligners showed more predictable force delivery patterns than thermoformed aligners.
Conclusions
Direct-printed TC-85 aligners demonstrated superior force consistency and reduced unwanted side effects compared with traditional PETG aligners. Although marginal design modifications did not significantly improve rotational efficiency, they effectively reduced unwanted intrusive forces.
3.Tagetes erecta Linn flower extract inhibits particulate matter 2.5-promoted epithelial-mesenchymal transition by attenuating reactive oxygen species generation in human retinal pigment epithelial ARPE-19 cells
Beom Su PARK ; EunJin BANG ; Hyesook LEE ; Gi-Young KIM ; Yung Hyun CHOI
Nutrition Research and Practice 2025;19(2):170-185
BACKGROUND/OBJECTIVES:
Particulate matter 2.5 (PM2.5) exposure can promote epithelialmesenchymal transition (EMT) in human retinal pigment epithelial (RPE) cells. The flowers of Tagetes erecta Linn, commonly known as marigold, are rich in diverse flavonoids and carotenoids and play a significant role in preventing cellular damage induced by oxidative stress, but the role of their extracts in RPE cells has not been reported. This study aimed to evaluate the influence of an ethanol extract of T. erecta Linn flower (TE) on PM2.5-induced EMT processes in RPE ARPE-19 cells.MATERIALS/METHODS: To investigate the protective effect of TE against ARPE-19 cell damage following PM2.5 treatment, cells were exposed to TE for 1 h before exposure to PM2.5 for 24 h. We investigated whether the efficacy of TE on suppressing PM2.5-induced EMT was related to antioxidant activity and the effect on the expression changes of factors involved in EMT regulation. Additionally, we further explored the role of intracellular signaling pathways associated with EMT inhibition.
RESULTS:
TE significantly blocked PM2.5-induced cytotoxicity while effectively preventing mitochondrial dysfunction, increased reactive oxygen species (ROS) generation, and mitochondrial membrane potential disruption. TE inhibited PM2.5-induced EMT and inflammatory response by suppressing the ROS-mediated transforming growth factor-β/ suppressor of mothers against decapentaplegic/mitogen-activated protein kinases signaling pathway.
CONCLUSION
Our results suggest that marigold extract is a highly effective in protection against PM2.5-induced eye damage.
4.Adjusted Global Antiphospholipid Syndrome Score Is Associated with End-Stage Kidney Disease in Patients with ANCA-Associated Vasculitis:A Single-Centre Pilot Study
Pil Gyu PARK ; Hyun Joon CHOI ; Yong-Beom PARK ; Sang-Won LEE
Yonsei Medical Journal 2025;66(6):337-345
Purpose:
The adjusted Global Antiphospholipid Syndrome (APS) Score (aGAPSS) was developed for assessing the probability of thrombotic events in APS patients. This study investigated whether the aGAPSS at diagnosis was associated with poor outcomes during follow-up in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).
Materials and Methods:
This study included 170 AAV patients who had the results of APS-related antibodies at diagnosis but were not diagnosed with APS. All-cause mortality, end-stage kidney disease (ESKD), cerebrovascular accident, and acute coronary syndrome were considered poor AAV outcomes. The aGAPSS comprises five items, with 5, 4, 4, 3, and 1 points assigned to anticardiolipin antibodies, anti-β2-glycoprotein 1 antibodies, lupus anticoagulants, hyperlipidaemia, and arterial hypertension at AAV diagnosis, respectively.
Results:
The median age of the 170 patients [93 microscopic polyangiitis (MPA), 44 granulomatosis with polyangiitis (GPA), and 33 eosinophilic GPA (EGPA)] was 63.0 years. The optimal cut-off of the aGAPSS at diagnosis for ESKD during follow-up was set as two using the receiver operating characteristic curve. AAV patients with an aGAPSS ≥2 at diagnosis exhibited a significantly reduced ESKD-free survival rate compared to those with an aGAPSS <2 at diagnosis (p=0.045). Additionally, MPA and GPA patients, excluding EGPA patients for whom the median aGAPSS at diagnosis was close to 0, also showed similar patterns to the results among the 170 patients with AAV (p=0.021).
Conclusion
This study is the first to demonstrate that the aGAPSS at diagnosis was significantly associated with ESKD during follow-up in AAV patients without APS.
5.Immunologic Response and Effects of COVID-19Vaccines in Patients with Antineutrophil Cytoplasmic Antibody-Associated Vasculitis
Ki Hyun LEE ; Hyunsue DO ; Jun Yong CHOI ; Yong-Beom PARK ; Sinyoung KIM ; Sang-Won LEE ; Su Jin JEONG
Yonsei Medical Journal 2025;66(5):259-268
Purpose:
The immunological response and adverse effects of antineutrophil cytoplasmic antibody-associated vasculitis (AAV) in patients receiving coronavirus disease-2019 (COVID-19) vaccines remain unclear. We aimed to evaluate the effects of these vaccines on AAV disease activity.
Materials and Methods:
We reviewed the medical records of 52 patients with AAV who had received at least second doses of the COVID-19 vaccine and evaluated their immunogenicity by measuring the anti-spike (S) antibody (Ab) titer levels using the Roche Elecsys® immunoassay. Responses to the Birmingham Vasculitis Activity Score (BVAS) tool and 36-Item Short Form Survey before and after vaccination were obtained to assess AAV disease activity. Vaccine reactivity was measured using a standardized questionnaire.
Results:
We enrolled 52 patients with AAV. No differences were found between those who received second and third doses of vaccination in terms of AAV type, disease activity, vaccine type, or the use of immunosuppressive agents, including steroids. The median anti-S Ab titer was 3967.0 after third doses compared to 419.0 after second doses (p=0.001). Except for mycophenolate mofetil (MMF), when immunosuppressants were administered in conjunction with steroids, the Ab titer was higher after the third vaccination than that after the second dose. The BVAS remained unchanged before and after second and third doses. No life-threatening adverse events were reported.
Conclusion
Although COVID-19 vaccine may not produce sufficient antibodies in patients taking MMF, the vaccine did not exacerbate disease activity or cause severe side effects. Therefore, COVID-19 vaccines should be considered in patients with AAV.
6.Effects of clear aligner edentulous space design on distal canine movement: An iterative finite element analysis in cases involving extraction
Seung Eun BAEK ; Kiyean KIM ; Youn-Kyung CHOI ; Sung-Hun KIM ; Seong-Sik KIM ; Ki Beom KIM ; Yong-Il KIM
The Korean Journal of Orthodontics 2025;55(3):193-201
Objective:
Using finite element method (FEM) analysis of a clear aligner (CA), this study aimed to investigate the effects of varying the edentulous space on canine distal bodily movement during space closure following maxillary first premolar extraction.
Methods:
FEM analysis was used to simulate distal canine bodily movement following maxillary first premolar extraction using CAs. Four CA designs for edentulous spaces were compared: no-pontic, full-pontic, halfpontic, and beam. Three-dimensional models of the tooth components and CA were created. The target was set at a 0.25-mm distal canine movement. Long-term tooth movement was simulated using an iterative calculation method.
Results:
All the groups initially showed crown displacement, distal tipping, and distal rotation.Over time, the movement patterns differed in relation to the design. The no-pontic design exhibited the greatest displacement and tipping. The beam design exhibited the largest initial displacement but showed the lowest displacement and tipping thereafter. Full- and half-pontic designs yielded intermediate results. Significant force reduction was observed immediately after CA application, and was followed by a gradual decrease. The mean tooth-movement achievement rate was approximately 76.7%.
Conclusions
The edentulous space design of the CA substantially affected tooth-movement behavior. An iterative simulation is necessary to evaluate longterm tooth-movement patterns. The beam design demonstrated optimal suitability for bodily movement with minimal tipping. For optimal results, additional setup or overcorrection may be necessary.
7.Force and moment analysis of clear aligners: Impact of material properties and design on premolar rotation
Dong-Woo KIM ; Hyun-Jun LEE ; Ki Beom KIM ; Sung-Hun KIM ; Seong-Sik KIM ; Soo-Byung PARK ; Youn-Kyung CHOI ; Yong-Il KIM
The Korean Journal of Orthodontics 2025;55(3):212-223
Objective:
To quantitatively analyze and compare the forces and moments generated by thermoformed polyethylene terephthalate glycol (PETG) and direct-printed TC-85 clear aligners (CAs), with various margin designs, during premolar rotation.
Methods:
In total, 132 CAs were fabricated and divided into four groups (n = 33 per group). Group C consisted of thermoformed PETG aligners with a 2 mm gingival margin. Group E comprised direct-printed TC-85 aligners with equi-gingival margin, whereas Group G utilized direct-printed TC-85 aligners with 2 mm gingival margins.Finally, Group T featured direct-printed TC-85 aligners with an additional 1 mm thickness at the mesial embrasure. The forces and moments were measured using a 6-axis force/moment transducer at 2°, 3°, and 4° of rotation. All measurements were conducted at 37°C to simulate intraoral conditions. Forces were measured in the buccolingual, anteroposterior, and vertical directions, while moments were measured in the mesiodistal, buccolingual, and rotational planes.
Results:
The PETG aligners (Group C) showed significantly increased buccal and posterior force across the rotation angles (P < 0.05), whereas the intrusive force remained consistent. In contrast, the TC-85 aligners maintained consistent forces across all rotation angles.Direct-printed aligners demonstrated significantly lower intrusive forces than PETG aligners (P < 0.001). Group T exhibited reduced unwanted forces while maintaining effective rotational moments. Furthermore, all direct-printed aligners showed more predictable force delivery patterns than thermoformed aligners.
Conclusions
Direct-printed TC-85 aligners demonstrated superior force consistency and reduced unwanted side effects compared with traditional PETG aligners. Although marginal design modifications did not significantly improve rotational efficiency, they effectively reduced unwanted intrusive forces.
8.Adjusted Global Antiphospholipid Syndrome Score Is Associated with End-Stage Kidney Disease in Patients with ANCA-Associated Vasculitis:A Single-Centre Pilot Study
Pil Gyu PARK ; Hyun Joon CHOI ; Yong-Beom PARK ; Sang-Won LEE
Yonsei Medical Journal 2025;66(6):337-345
Purpose:
The adjusted Global Antiphospholipid Syndrome (APS) Score (aGAPSS) was developed for assessing the probability of thrombotic events in APS patients. This study investigated whether the aGAPSS at diagnosis was associated with poor outcomes during follow-up in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).
Materials and Methods:
This study included 170 AAV patients who had the results of APS-related antibodies at diagnosis but were not diagnosed with APS. All-cause mortality, end-stage kidney disease (ESKD), cerebrovascular accident, and acute coronary syndrome were considered poor AAV outcomes. The aGAPSS comprises five items, with 5, 4, 4, 3, and 1 points assigned to anticardiolipin antibodies, anti-β2-glycoprotein 1 antibodies, lupus anticoagulants, hyperlipidaemia, and arterial hypertension at AAV diagnosis, respectively.
Results:
The median age of the 170 patients [93 microscopic polyangiitis (MPA), 44 granulomatosis with polyangiitis (GPA), and 33 eosinophilic GPA (EGPA)] was 63.0 years. The optimal cut-off of the aGAPSS at diagnosis for ESKD during follow-up was set as two using the receiver operating characteristic curve. AAV patients with an aGAPSS ≥2 at diagnosis exhibited a significantly reduced ESKD-free survival rate compared to those with an aGAPSS <2 at diagnosis (p=0.045). Additionally, MPA and GPA patients, excluding EGPA patients for whom the median aGAPSS at diagnosis was close to 0, also showed similar patterns to the results among the 170 patients with AAV (p=0.021).
Conclusion
This study is the first to demonstrate that the aGAPSS at diagnosis was significantly associated with ESKD during follow-up in AAV patients without APS.
9.Immunologic Response and Effects of COVID-19Vaccines in Patients with Antineutrophil Cytoplasmic Antibody-Associated Vasculitis
Ki Hyun LEE ; Hyunsue DO ; Jun Yong CHOI ; Yong-Beom PARK ; Sinyoung KIM ; Sang-Won LEE ; Su Jin JEONG
Yonsei Medical Journal 2025;66(5):259-268
Purpose:
The immunological response and adverse effects of antineutrophil cytoplasmic antibody-associated vasculitis (AAV) in patients receiving coronavirus disease-2019 (COVID-19) vaccines remain unclear. We aimed to evaluate the effects of these vaccines on AAV disease activity.
Materials and Methods:
We reviewed the medical records of 52 patients with AAV who had received at least second doses of the COVID-19 vaccine and evaluated their immunogenicity by measuring the anti-spike (S) antibody (Ab) titer levels using the Roche Elecsys® immunoassay. Responses to the Birmingham Vasculitis Activity Score (BVAS) tool and 36-Item Short Form Survey before and after vaccination were obtained to assess AAV disease activity. Vaccine reactivity was measured using a standardized questionnaire.
Results:
We enrolled 52 patients with AAV. No differences were found between those who received second and third doses of vaccination in terms of AAV type, disease activity, vaccine type, or the use of immunosuppressive agents, including steroids. The median anti-S Ab titer was 3967.0 after third doses compared to 419.0 after second doses (p=0.001). Except for mycophenolate mofetil (MMF), when immunosuppressants were administered in conjunction with steroids, the Ab titer was higher after the third vaccination than that after the second dose. The BVAS remained unchanged before and after second and third doses. No life-threatening adverse events were reported.
Conclusion
Although COVID-19 vaccine may not produce sufficient antibodies in patients taking MMF, the vaccine did not exacerbate disease activity or cause severe side effects. Therefore, COVID-19 vaccines should be considered in patients with AAV.
10.Efficacy and Safety of Taltirelin Hydrate in Patients With Ataxia Due to Spinocerebellar Degeneration
Jin Whan CHO ; Jee-Young LEE ; Han-Joon KIM ; Joong-Seok KIM ; Kun-Woo PARK ; Seong-Min CHOI ; Chul Hyoung LYOO ; Seong-Beom KOH
Journal of Movement Disorders 2025;18(1):35-44
Objective:
We conducted this study to assess the efficacy and safety of taltirelin hydrate (TH) in patients with ataxia due to spinocerebellar degeneration (SCD).
Methods:
Patients were randomly assigned to either the taltirelin group (5 mg orally, twice daily) or the control group. The primary endpoint was the change in the Korean version of the Scale for the Assessment and Rating of Ataxia (K-SARA) score at 24 weeks. The secondary endpoints included changes in the K-SARA score at 4 and 12 weeks as well as the Clinical Global Impression Scale, the five-level version of the EuroQol five-dimensional questionnaire, the Tinetti balance test, and gait analysis at 4, 12, and 24 weeks.
Results:
A total of 149 patients (hereditary:nonhereditary=86:63) were enrolled. There were significant differences in the change in the K-SARA score at 24 weeks from baseline between the taltirelin group and the control group (-0.51±2.79 versus 0.36±2.62, respectively; p=0.0321). For the K-SARA items, the taltirelin group had significantly lower “Stance” and “Speech disturbance” subscores than the control group (-0.04±0.89 versus 0.23±0.79 and -0.07±0.74 versus 0.18±0.67; p=0.0270 and 0.0130, respectively). However, there were no significant differences in changes in other secondary efficacy outcome measures at 24 weeks from baseline between the two treatment arms (p>0.05).
Conclusion
Clinicians might consider the use of TH in the treatment of patients with ataxia due to SCD.

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