1.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.
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.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.
4.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.
5.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.
6.Korean Multicenter Registry of ELUVIA Stent for Femoropopliteal Artery Disease: K-ELUVIA Registry
Joongmin KIM ; Young-Guk KO ; Seung-Jun LEE ; Chul-Min AHN ; Seung-Woon RHA ; Cheol Ung CHOI ; Pil-Ki MIN ; Jong Kwan PARK ; Ji-Yong JANG ; Young Jin YOUN ; Tae-Soo KANG ; Chang-Hwan YOON ; Donghoon CHOI
Korean Circulation Journal 2024;54(9):565-576
Background and Objectives:
The K-ELUVIA study aimed to investigate the clinical effectiveness and safety of Eluvia™, a polymer-coated, paclitaxel-eluting stent, for femoropopliteal artery disease using data from a prospective Korean multicenter registry.
Methods:
A total of 105 patients with femoropopliteal artery disease who received endovascular treatment (EVT) with Eluvia™ stents at 7 Korean sites were enrolled in a prospective cohort and followed for 2 years. The primary endpoint was the 2-year clinical patency. The secondary endpoint was 2-year freedom from clinically driven target lesion revascularization (TLR).
Results:
Mean patient age was 68.2±10.4 years, and most patients (82.7%) were male. Mean lesion length was 168.3±117.6 mm. Chronic total occlusion was found in 57.7% of patients.Trans-Atlantic Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II) type C or D lesions were present in 46.1% of patients. Procedural success was achieved in 99.0% of patients. The clinical patency rate was 84.4% at 1 year after EVT and 76.3% at 2 years post-EVT. The freedom from TLR rate was 89.1% at 1 year after EVT and 79.1% at 2 years post-EVT. Chronic total occlusion (hazard ratio [HR], 3.53; 95% confidence interval [CI], 1.08–11.67; p=0.039) and smaller mean stent diameter (HR, 0.40; 95% CI, 0.16– 0.98; p=0.044) were identified as independent predictors of loss of clinical patency at 2 years.
Conclusions
The K-ELUVIA study demonstrated favorable 2-year clinical effectiveness and safety outcomes of Eluvia stent for femoropopliteal artery lesions in real-world practice.
7.Epidemiological Characteristics of HIV-Infected Individuals by the Registration for Special Exempted Calculation: A Nationwide Cohort Study
Yunsu CHOI ; Kyoung Hwan AHN ; Soo Min KIM ; Bo Youl CHOI ; Jungsoon CHOI ; Jung Ho KIM ; Shin-Woo KIM ; Youn Jeong KIM ; Yoon Hee JUN ; Bo Young PARK
Infection and Chemotherapy 2024;56(4):510-521
Background:
The Korean government is implementing policy to reduce medical costs and improve treatment related for human immunodeficiency virus (HIV) patients. The level of cost reduction and the benefits provided vary depending on how individuals with HIV utilize the system. This study aims to determine exact HIV prevalence by analyzing healthcare utilization patterns and examining differences in healthcare usage based on how individuals pay for their medical expenses.
Materials and Methods:
We analyzed National Health Insurance Service (NHIS) claims data from 2002 to 2021. From a total of 106,675 individuals with at least one HIV-related claim, 22,779 participants were selected for this study.
Results:
Data from Korea Disease Control and Prevention Agency annual reports indicated that 93% of HIV patients were male, while NHIS data showed 84%. In the analysis of those exempted from registration, it was found that the registration rate for female patients is notably low, with adults between the ages of 20 and 40 making up 80% of the total. The registration rate in Gangwon State was lower than Seoul. The treatment experience rate was much higher in the registered group (93.0%) than the unregistered group (4.9%). Also, there was a big difference in treatment continuity rates: 76.2% for registered individuals and 2.8% for non-registered individuals.
Conclusion
The exempt calculation system for health insurance improves HIV care. However, those diagnosed anonymously or with reduced medical costs may be less likely to continue HIV treatment, so a new policy is needed to ensure anonymity and treatment continuity.
8.Korean Multicenter Registry of ELUVIA Stent for Femoropopliteal Artery Disease: K-ELUVIA Registry
Joongmin KIM ; Young-Guk KO ; Seung-Jun LEE ; Chul-Min AHN ; Seung-Woon RHA ; Cheol Ung CHOI ; Pil-Ki MIN ; Jong Kwan PARK ; Ji-Yong JANG ; Young Jin YOUN ; Tae-Soo KANG ; Chang-Hwan YOON ; Donghoon CHOI
Korean Circulation Journal 2024;54(9):565-576
Background and Objectives:
The K-ELUVIA study aimed to investigate the clinical effectiveness and safety of Eluvia™, a polymer-coated, paclitaxel-eluting stent, for femoropopliteal artery disease using data from a prospective Korean multicenter registry.
Methods:
A total of 105 patients with femoropopliteal artery disease who received endovascular treatment (EVT) with Eluvia™ stents at 7 Korean sites were enrolled in a prospective cohort and followed for 2 years. The primary endpoint was the 2-year clinical patency. The secondary endpoint was 2-year freedom from clinically driven target lesion revascularization (TLR).
Results:
Mean patient age was 68.2±10.4 years, and most patients (82.7%) were male. Mean lesion length was 168.3±117.6 mm. Chronic total occlusion was found in 57.7% of patients.Trans-Atlantic Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II) type C or D lesions were present in 46.1% of patients. Procedural success was achieved in 99.0% of patients. The clinical patency rate was 84.4% at 1 year after EVT and 76.3% at 2 years post-EVT. The freedom from TLR rate was 89.1% at 1 year after EVT and 79.1% at 2 years post-EVT. Chronic total occlusion (hazard ratio [HR], 3.53; 95% confidence interval [CI], 1.08–11.67; p=0.039) and smaller mean stent diameter (HR, 0.40; 95% CI, 0.16– 0.98; p=0.044) were identified as independent predictors of loss of clinical patency at 2 years.
Conclusions
The K-ELUVIA study demonstrated favorable 2-year clinical effectiveness and safety outcomes of Eluvia stent for femoropopliteal artery lesions in real-world practice.
9.Association between Age-Related Macular Degeneration and Arthritis: Data from the Korean National Health and Nutrition Examination Survey for 2017 and 2018
Jun Sung NAH ; Junho MUN ; Kyoung Lae KIM ; Yong-Kyu KIM ; Youn Joo CHOI ; Sung Pyo PARK ; Kyeong Ik NA
Annals of Optometry and Contact Lens 2024;23(4):171-177
Purpose:
We examined the association between age-related macular degeneration (AMD) and arthritis.
Methods:
Using data from the Korea National Health and Nutrition Examination Survey for 2017 and 2018, we conducted a complex sample analysis of 6,993 individuals with recorded information on AMD, as well as the diagnosis and treatment of osteoarthritis (OA) and rheumatoid arthritis (RA). We compared the diagnosis and treatment of arthritis between the AMD and control groups using logistic regression analysis, with a specific focus on the treatment among patients with arthritis.
Results:
In the AMD group (n = 1,118) and the control group (n = 5,875), univariate logistic regression analysis showed substantial differences in the diagnosis and treatment of OA and RA. However, after adjusting for age, alcohol consumption, diabetes mellitus, and hypertension in multivariate logistic regression analysis, these differences were no longer substantial. Among patients with OA (n = 246 in the AMD group and n = 821 in the control group), there was a significant association between AMD and OA treatments (odds ratio 1.511, 95% confidence interval 1.051-2.172).
Conclusions
Patients diagnosed with and treated for OA had a higher likelihood of concurrent AMD than those who did not receive treatment. Therefore, ophthalmic examinations and closer monitoring are recommended for these patients.
10.Epidemiological Characteristics of HIV-Infected Individuals by the Registration for Special Exempted Calculation: A Nationwide Cohort Study
Yunsu CHOI ; Kyoung Hwan AHN ; Soo Min KIM ; Bo Youl CHOI ; Jungsoon CHOI ; Jung Ho KIM ; Shin-Woo KIM ; Youn Jeong KIM ; Yoon Hee JUN ; Bo Young PARK
Infection and Chemotherapy 2024;56(4):510-521
Background:
The Korean government is implementing policy to reduce medical costs and improve treatment related for human immunodeficiency virus (HIV) patients. The level of cost reduction and the benefits provided vary depending on how individuals with HIV utilize the system. This study aims to determine exact HIV prevalence by analyzing healthcare utilization patterns and examining differences in healthcare usage based on how individuals pay for their medical expenses.
Materials and Methods:
We analyzed National Health Insurance Service (NHIS) claims data from 2002 to 2021. From a total of 106,675 individuals with at least one HIV-related claim, 22,779 participants were selected for this study.
Results:
Data from Korea Disease Control and Prevention Agency annual reports indicated that 93% of HIV patients were male, while NHIS data showed 84%. In the analysis of those exempted from registration, it was found that the registration rate for female patients is notably low, with adults between the ages of 20 and 40 making up 80% of the total. The registration rate in Gangwon State was lower than Seoul. The treatment experience rate was much higher in the registered group (93.0%) than the unregistered group (4.9%). Also, there was a big difference in treatment continuity rates: 76.2% for registered individuals and 2.8% for non-registered individuals.
Conclusion
The exempt calculation system for health insurance improves HIV care. However, those diagnosed anonymously or with reduced medical costs may be less likely to continue HIV treatment, so a new policy is needed to ensure anonymity and treatment continuity.

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