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.The impact of CYP2D6 on donepezil concentration and its lack of effect on the treatment response and adverse effect in Korean patients with Alzheimer’s disease
Tae-Eun KIM ; Jung‑Woo BAE ; Seongkuk HONG ; Hong Jun JEON ; Yeonsil MOON
The Korean Journal of Physiology and Pharmacology 2025;29(2):227-233
Donepezil, an acetylcholinesterase inhibitor, is widely used for managing the symptoms of Alzheimer’s disease (AD), yet its clinical response varies widely among individuals. This study aims to investigate the influence of CYP2D6 genetic variants on donepezil concentration, treatment response, and adverse effects in Korean patients with AD dementia. We conducted a longitudinal study involving 76 patients receiving either 5 mg or 10 mg of donepezil. Genetic testing identified 9 CYP2D6 alleles, categorizing patients by metabolizing abilities. Blood sampling for plasma concentrations of donepezil were performed at steady-state. Mini-Mental State Examination (MMSE) were conducted at 12, 24 and 36 months after the initiation of treatment. Adverse events were collected throughout the study period.Donepezil plasma concentrations differed significantly among metabolizer statuses (mean 56.8 ± 27.1 ng/ml in normal metabolizers vs. 69.6 ± 30.1 ng/ml in intermediate metabolizers, p = 0.042), but these differences did not affect cognitive function over three years as assessed by MMSE. Additionally, there was no significant correlation between donepezil plasma concentration and adverse events. Our study is the first to elucidate the associations between CYP2D6 genotype and the concentration, clinical response or adverse events of donepezil in Korean patients with AD dementia. Larger studies are necessary to fully understand the impact of CYP2D6 genetic variants on therapeutic outcomes with donepezil.
3.Pericapsular Nerve Group Block with Periarticular Injection for Pain Management after Total Hip Arthroplasty: A Randomized Controlled Trial
Hun Sik CHO ; Bo Ra LEE ; Hyuck Min KWON ; Jun Young PARK ; Hyeong Won HAM ; Woo-Suk LEE ; Kwan Kyu PARK ; Tae Sung LEE ; Yong Seon CHOI
Yonsei Medical Journal 2025;66(4):233-239
Purpose:
The purpose of this study was to compare the effectiveness of pericapsular nerve group (PENG) block with periarticular multimodal drug injection (PMDI) on postoperative pain management and surgical outcomes in patients who underwent total hip arthroplasty (THA). We hypothesized that PENG block with PMDI would exhibit superior effects on postoperative pain control after THA compared to PMDI alone.
Materials and Methods:
From April 2022 to February 2023, 58 patients who underwent THA were randomly assigned into two groups: PENG block with PMDI group (n=29) and PMDI-only group (n=29). Primary outcomes were postoperative numeric rating scale (NRS) at rest and during activity at 6, 24, and 48 hours postoperatively. Secondary outcomes were postoperative complications (nausea and vomiting), Richards-Campbell Sleep Questionnaire (RCSQ) score, length of hospital stay, Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index, Harris Hip Score (HHS), and total morphine usage after surgery.
Results:
There was no significant difference in postoperative pain for either resting NRS or active NRS. Postoperative nausea and vomiting, RCSQ score, length of hospital stay, WOMAC index, HHS, and total morphine usage exhibited no significant differences between the two groups.
Conclusion
Both groups showed no significant differences in postoperative pain and clinical outcomes, indicating that the addition of PENG block to PMDI does not improve pain management after applying the posterolateral approach of THA. PMDI alone during THA would be an efficient, fast, and safe method for managing postoperative pain. This article was registered with ClinicalTrials.gov (Gov ID: NCT05320913).
4.Dual Disruption of DNA Repair by a Novel CHK2 Inhibitor, ART-446, and Olaparib is a Promising Strategy for Triple-Negative Breast Cancer Therapy
Hong-Jun KANG ; Young-Woo KANG ; Ha-Young LEE ; Sojung HA ; Jong Oh KIM ; Woo-Young KIM ; Taegon BAIK
Biomolecules & Therapeutics 2025;33(3):458-469
Triple-negative breast cancer (TNBC) is an aggressive cancer subtype lacking targeted therapies and is characterized by highrecurrence rates and poor prognosis. Recent advances in targeting DNA damage response (DDR) pathways using poly (ADP‒ri-bose) polymerase (PARP) inhibitors offer promising therapeutic strategies, especially for TNBC patients with BRCA1/2 mutations.This study reports the development and characterization of ART-446, a novel and selective CHK2 inhibitor. ART-446 showed potent activity against TNBC, regardless of BRCA deficiency, and it also reversed PARP inhibitor resistance. ART-446 potentlyinhibited CHK2 (IC50 : 9.06 nM) with high selectivity over other kinases; it synergized with the PARP inhibitor olaparib, enhancingDNA damage, inducing G2/M cell cycle arrest, and promoting apoptosis in both BRCA-mutant and wild-type TNBC cells. Mechanistic analyses revealed that ART-446 sensitized BRCA mutant and WT cells to PARP inhibitors by impairing DNA repair and increasing the accumulation of DNA damage. Importantly, ART-446 disrupted both homologous recombination and nonhomologous end-joining repair pathways, addressing a key limitation of PARP inhibitor monotherapy—resistance in BRCA-proficient cancers.In vivo, the combination of ART-446 and olaparib significantly reduced tumor growth in TNBC xenograft models without noticeable toxicity. The combined treatment increased DNA damage signaling, as evidenced by elevated γH2AX levels, and enhanced the sensitivity of BRCA2-deficient cells to ART-446. These findings underscore the potential of ART-446 to exploit DNA repair deficiencies and overcome resistance mechanisms associated with PARP inhibitors. By addressing the limitations of current treatments and expanding the utility of PARP inhibitors, ART-446 represents a promising candidate for DDR-targeted therapies, offering a novel approach to improve the outcomes of patients with TNBC.
5.Target-Enhanced Whole-Genome Sequencing Shows Clinical Validity Equivalent to Commercially Available Targeted Oncology Panel
Sangmoon LEE ; Jin ROH ; Jun Sung PARK ; Islam Oguz TUNCAY ; Wonchul LEE ; Jung-Ah KIM ; Brian Baek-Lok OH ; Jong-Yeon SHIN ; Jeong Seok LEE ; Young Seok JU ; Ryul KIM ; Seongyeol PARK ; Jaemo KOO ; Hansol PARK ; Joonoh LIM ; Erin CONNOLLY-STRONG ; Tae-Hwan KIM ; Yong Won CHOI ; Mi Sun AHN ; Hyun Woo LEE ; Seokhwi KIM ; Jang-Hee KIM ; Minsuk KWON
Cancer Research and Treatment 2025;57(2):350-361
Purpose:
Cancer poses a significant global health challenge, demanding precise genomic testing for individualized treatment strategies. Targeted-panel sequencing (TPS) has improved personalized oncology but often lacks comprehensive coverage of crucial cancer alterations. Whole-genome sequencing (WGS) addresses this gap, offering extensive genomic testing. This study demonstrates the medical potential of WGS.
Materials and Methods:
This study evaluates target-enhanced WGS (TE-WGS), a clinical-grade WGS method sequencing both cancer and matched normal tissues. Forty-nine patients with various solid cancer types underwent both TE-WGS and TruSight Oncology 500 (TSO500), one of the mainstream TPS approaches.
Results:
TE-WGS detected all variants reported by TSO500 (100%, 498/498). A high correlation in variant allele fractions was observed between TE-WGS and TSO500 (r=0.978). Notably, 223 variants (44.8%) within the common set were discerned exclusively by TE-WGS in peripheral blood, suggesting their germline origin. Conversely, the remaining subset of 275 variants (55.2%) were not detected in peripheral blood using the TE-WGS, signifying them as bona fide somatic variants. Further, TE-WGS provided accurate copy number profiles, fusion genes, microsatellite instability, and homologous recombination deficiency scores, which were essential for clinical decision-making.
Conclusion
TE-WGS is a comprehensive approach in personalized oncology, matching TSO500’s key biomarker detection capabilities. It uniquely identifies germline variants and genomic instability markers, offering additional clinical actions. Its adaptability and cost-effectiveness underscore its clinical utility, making TE-WGS a valuable tool in personalized cancer treatment.
6.The comparative study of Stretta radiofrequency and anti-reflux mucosectomy in the management of intractable gastroesophageal reflux disease: a single-center retrospective study from Korea
Ah Young LEE ; Ji Woo CHOI ; Jeong Haeng HEO ; Jun Young CHUNG ; Seong Hwan KIM ; Joo Young CHO
Clinical Endoscopy 2025;58(3):409-417
Background/Aims:
Chronic gastroesophageal reflux disease (GERD) requires symptom relief and treatment of associated conditions. In this study, we aimed to compare anti-reflux mucosectomy (ARMS) and Stretta radiofrequency (SRF) for treating patients with chronic GERD who are unresponsive to proton pump inhibitors (PPIs) and to identify the indications for each procedure.
Methods:
Data of patients who underwent ARMS or SRF between March 2021 and April 2023 were analyzed. Changes in GERD questionnaire (GERDQ) scores, endoscopic Los Angeles (LA) grade, flap valve grade (FVG) based on Hill’s type, EndoFLIP distensibility index (DI), endoscopic Barrett’s epithelium (BE) resolution rate, and PPI withdrawal rate were compared between the two groups.
Results:
Improvements in the GERDQ scores and PPI withdrawal rates were similar between the groups. The ARMS group showed significantly better changes in endoscopic LA grade, FVG, and EndoFLIP DI than the SRF group. The complications were more prevalent in the ARMS group than in the SRF group.
Conclusions
The change in endoscopic LA grade before and after the procedure was significantly higher in the ARMS group than in the SRF group. Significant improvements in endoscopic FVG, BE resolution, and EndoFLIP DI were observed only with the ARMS group.
7.Additional Screw Added to the Femoral Neck System Could Enhance the Stability of Pauwel Type III Femoral Neck Fractures:a Finite Element Analysis
Yonghan CHA ; Sunghoon PARK ; Chang-Ho JUNG ; Jin-Woo KIM ; Jun-Il YOO ; Jung-Taek KIM ; Yongho JEON ; Kyeong Jin HAN
Clinics in Orthopedic Surgery 2025;17(2):204-215
Background:
This study explores effective fixation methods for Pauwel type III femoral neck fractures by evaluating the biomechanical benefits of adding a screw to the Femoral Neck System (FNS).
Methods:
Computed tomography (CT) scans of an 82-year-old female patient with an intertrochanteric fracture were used to establish a finite element femur model with heterogeneous material properties. Finite element models of Pauwel type III fractures were created with and without an additional screw. The central and inferior trajectories of the FNS bolt were examined separately and combined with an additional screw for virtual fixation. Walking and stair-climbing loads were applied.
Results:
With the addition of a screw, both peak maximum and minimum principal strains consistently stayed comparable or decreased in models with both central and inferior bolt trajectories, while the volume of elements with principal strain exceeding 1% decreased by more than half. The peak von Mises stress observed in the implants ranged from 215.7 to 359.3 MPa, remaining below the titanium alloy's yield strength of 800 MPa. For normal walking, the addition of a screw to the central bolt trajectory model decreased the fracture gap by 50.6% and reduced sliding distance by 8.6%. For the inferior bolt trajectory, the gap was reduced by 57.9% and sliding distance by 25.0%.Under stair-climbing conditions, these improvements were also evident; the central trajectory model saw a halved fracture gap and a 7.9% decrease in sliding distance, while the inferior trajectory model experienced a 55.7% gap reduction and a 27.2% decrease in sliding distance. The additional screw increased the area ratio of the fracture site experiencing interfragmentary compression 34%–39%, while the additional screw alleviated peak interfragmentary compression by 12%–18% under both normal walking and stair-climbing conditions.
Conclusions
The addition of a screw reduced the fracture gap, sliding distance, and peak interfragmentary compression, while increasing the area ratio of interfragmentary compression under both walking and stair-climbing loads, regardless of the FNS bolt trajectory, suggesting a better mechanical environment for fracture healing.
8.Reduction Loss Despite Adequate Volar Locking Plate Fixation in Distal Radius Fractures: Analysis of Characteristics and Follow-up Management
Chi-Hoon OH ; Seungyeon KANG ; Sung Woo LEE ; Soo-Hong HAN ; Jun-Ku LEE
Clinics in Orthopedic Surgery 2025;17(3):478-487
Background:
The management of distal radius fractures (DRFs) has evolved with the introduction of volar locking plate (VLP) fixation.Nevertheless, despite the low occurrence rates, reduction loss following VLP fixation has been reported in several studies. Our objective was to determine the incidence and features of reduction loss in patients despite the appropriate application of VLP fixation for DRF.
Methods:
This retrospective study was conducted between March 2017 and August 2023, during which a single hand surgeon performed VLP procedures for DRFs. This study included 379 patients (382 wrists) including 3 patients who underwent bilateral surgery. We identified patients who experienced reduction loss after VLP fixation (group 1) and patients without stability problems (group 2) and compared the 2 groups.
Results:
The mean age of the patients was 63.5 years, with a standard deviation of 13.8. There were 90 male patients (23.6%) and 289 female patients (75.7%). We identified 14 cases of DRFs, in which reduction loss occurred even after VLP fixation during the follow-up period (group 1, 3.7%). The remaining DRFs were assigned to group 2 (n=368, 96.3%). Among the 14 patients, 7 cases of screw breakage were identified as causing the loss of fracture reduction. As the joint surface collapsed and sank down to the distal row locking screw, 4 cases presented with distal locking screws penetrating into the radiocarpal joint. There were no significant differences between the 2 groups in terms of sex, weight, fracture arm direction, and Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) fracture classification. However, patients in group 1 were statistically significantly older than those in group 2 (average age, 77.5 years vs. 62 years). Among 4 patients experiencing distal screw violation of the radiocarpal joints, 3 underwent partial or complete screw removal immediately after fracture consolidation or union.
Conclusions
While rare, reduction loss remains a potential complication following VLP fixation, especially in elderly patients with intra-articular DRFs. However, with diligent monitoring and timely intervention, such as implant removal if necessary, acceptable outcomes can still be attained.
9.Powered Tool for the Removal of a Well-Fixed Acetabular Cup: A Comparative Experimental Study
Jun Young CHUNG ; Yonghan CHA ; Chang-Ho JUNG ; Jin-Woo KIM ; Jun-Il YOO ; Jung-Taek KIM ; Yongho JEON
Clinics in Orthopedic Surgery 2025;17(3):372-380
Background:
The removal of a well-fixed acetabular cup is a challenging, labor-intensive, and time-consuming step during revision hip arthroplasty. Although the advent of the manual osteotome, Explant, has simplified the procedure, it is still a stressful process as it dissipates the surgeon’s strength and time and risks an iatrogenic pelvic fracture. Recently, EZX, a powered tool for extraction of well-fixed acetabular cups with semicircular blade was invented. This study aimed to compare Explant and EZX in an experimental condition for their efficacy and safety.
Methods:
Cementless acetabular cups were press-fitted to 20 hemipelvic polyurethane models using foam adhesives. Ten cups were removed with each tool for comparison of the elapsed time, loads on the entire hemipelvis, periacetabular strain and temperature, volume of periacetabular bone removed, and diameter of the remaining acetabular rim. Strains and loads were quantitatively assessed using strain gauges and load cells for precise and reliable measurements.
Results:
The mean duration required to remove a well-fixed cup with EZX was 38.5 seconds (range, 25–55), whereas that with Explant was 543.7 seconds (range, 214–1,051) (p < 0.001). The load on the entire hemipelvis with EZX (mean, 9.1 kgf; range, 6.4–11.3) was 33% lower than that with Explant (mean, 13.6 kgf; range, 9.2–17.1) (p < 0.001). The periacetabular peak strains at the 3 positions with EZX were significantly lower than those with Explant (p < 0.001). The temperature during the removal did not differ significantly between the 2 tools. Although the mean volume of bone loss with Explant was 2.4 mL more than that with EZX (p < 0.001), the mean diameters of the remaining acetabular rim were not significantly different, measuring 54.1 mm with both tools.
Conclusions
The present experiment revealed that a well-fixed cup could be removed using a powered tool with less strength and time and less load on the entire pelvis. Although the powered tool removed a larger volume of bone, the diameters of the remaining acetabular rims were equivalent. This tool may help surgeons remove well-fixed cups in a short time and reduce the deforming load on the bone around the cup without increasing the size of the subsequent reconstruction cup.
10.A Narrative Review on the Double Pulley-Triple Row Technique for Large to Massive Rotator Cuff Repair
Vivek Kumar MORYA ; Jun LANG ; Yong-beom LEE ; Jung Woo KIM ; Kang Uk LEE ; Kyu-Cheol NOH
Clinics in Orthopedic Surgery 2025;17(3):359-371
Rotator cuff tears are common shoulder injuries that often necessitate surgical intervention, particularly when nonoperative treatments fail. Arthroscopic rotator cuff repair is the current gold standard; however, challenges, such as high retear rates, especially in large tears, persist. Traditional techniques, such as single-row and double-row repairs, have limitations in fully restoring the anatomical footprint and ensuring optimal healing. This review examines the novel double pulley-triple row technique, which aims to overcome these limitations by enhancing the footprint contact area, load distribution, and tendon healing. By evaluating the double pulley-triple row method in comparison to established techniques, this study explores the potential advantages, limitations, and future directions of rotator cuff repair.

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