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.

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.

Background: This study compares ultrasound and surgical findings of anatomical variations in de Quervain’s disease. Methods: Seventy-four wrists from patients with unilateral de Quervain’s disease were examined through ultrasonography and surgery. Presence of intracompartment septum, abductor pollicis longus (APL) slips, and selective stenosis were verified by both methods. Two orthopedic surgeons assessed ultrasound findings for intra- and interobserver reliability. Results: Amongst 74 participants (43 women and 31 men), 60.8% had a complete septum, 31.1% had an incomplete septum, and 8.1% had no septum; 70.3% had multi-slip APL and 66.2% had extensor pollicis brevis stenosis. Surgical and ultrasonographic findings displayed a high level of sensitivity and specificity. Intraobserver reliability was high, and interobserver reliability was substantial. Conclusions The study confirms ultrasonography’s reliability in identifying anatomical variations in de Quervain’s disease, with high sensitivity, specificity, and substantial intra- and interobserver reliability, emphasizing its usefulness in preoperative assessment and planning.

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.

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.

Purpose: Since 1995, the Korean Gastric Cancer Association (KGCA) has been periodically conducting nationwide surveys on patients with surgically treated gastric cancer. This study details the results of the survey conducted in 2023. Materials and Methods: The survey was conducted from March to December 2024 using a standardized case report form. Data were collected on 86 items, including patient demographics, tumor characteristics, surgical procedures, and surgical outcomes. The results of the 2023 survey were compared with those of previous surveys. Results: Data from 12,751 cases were collected from 66 institutions. The mean patient age was 64.6 years, and the proportion of patients aged ≥71 years increased from 9.1% in 1995 to 31.7% in 2023. The proportion of upper-third tumors slightly decreased to 16.8% compared to 20.9% in 2019. Early gastric cancer accounted for 63.1% of cases in 2023.Regarding operative procedures, a totally laparoscopic approach was most frequently applied (63.2%) in 2023, while robotic gastrectomy steadily increased to 9.5% from 2.1% in 2014.The most common anastomotic method was the Billroth II procedure (48.8%) after distal gastrectomy and double-tract reconstruction (51.9%) after proximal gastrectomy in 2023.However, the proportion of esophago-gastrostomy with anti-reflux procedures increased to 30.9%. The rates of post-operative mortality and overall complications were 1.0% and 15.3%, respectively. Conclusions The results of the 2023 nationwide survey demonstrate the current status of gastric cancer treatment in Korea. This information will provide a basis for future gastric cancer research.

Background: This study compares ultrasound and surgical findings of anatomical variations in de Quervain’s disease. Methods: Seventy-four wrists from patients with unilateral de Quervain’s disease were examined through ultrasonography and surgery. Presence of intracompartment septum, abductor pollicis longus (APL) slips, and selective stenosis were verified by both methods. Two orthopedic surgeons assessed ultrasound findings for intra- and interobserver reliability. Results: Amongst 74 participants (43 women and 31 men), 60.8% had a complete septum, 31.1% had an incomplete septum, and 8.1% had no septum; 70.3% had multi-slip APL and 66.2% had extensor pollicis brevis stenosis. Surgical and ultrasonographic findings displayed a high level of sensitivity and specificity. Intraobserver reliability was high, and interobserver reliability was substantial. Conclusions The study confirms ultrasonography’s reliability in identifying anatomical variations in de Quervain’s disease, with high sensitivity, specificity, and substantial intra- and interobserver reliability, emphasizing its usefulness in preoperative assessment and planning.

Background: This study compares ultrasound and surgical findings of anatomical variations in de Quervain’s disease. Methods: Seventy-four wrists from patients with unilateral de Quervain’s disease were examined through ultrasonography and surgery. Presence of intracompartment septum, abductor pollicis longus (APL) slips, and selective stenosis were verified by both methods. Two orthopedic surgeons assessed ultrasound findings for intra- and interobserver reliability. Results: Amongst 74 participants (43 women and 31 men), 60.8% had a complete septum, 31.1% had an incomplete septum, and 8.1% had no septum; 70.3% had multi-slip APL and 66.2% had extensor pollicis brevis stenosis. Surgical and ultrasonographic findings displayed a high level of sensitivity and specificity. Intraobserver reliability was high, and interobserver reliability was substantial. Conclusions The study confirms ultrasonography’s reliability in identifying anatomical variations in de Quervain’s disease, with high sensitivity, specificity, and substantial intra- and interobserver reliability, emphasizing its usefulness in preoperative assessment and planning.