1.Improving appendix cancer prediction with SHAP-based feature engineering for machine learning models: a prediction study
The Ewha Medical Journal 2025;48(2):e31-
Purpose:
This study aimed to leverage Shapley additive explanation (SHAP)-based feature engineering to predict appendix cancer. Traditional models often lack transparency, hindering clinical adoption. We propose a framework that integrates SHAP for feature selection, construction, and weighting to enhance accuracy and clinical relevance.
Methods:
Data from the Kaggle Appendix Cancer Prediction dataset (260,000 samples, 21 features) were used in this prediction study conducted from January through March 2025, in accordance with TRIPOD-AI guidelines. Preprocessing involved label encoding, SMOTE (synthetic minority over-sampling technique) to address class imbalance, and an 80:20 train-test split. Baseline models (random forest, XGBoost, LightGBM) were compared; LightGBM was selected for its superior performance (accuracy=0.8794). SHAP analysis identified key features and guided 3 engineering steps: selection of the top 15 features, construction of interaction-based features (e.g., chronic severity), and feature weighting based on SHAP values. Performance was evaluated using accuracy, precision, recall, and F1-score.
Results:
Four LightGBM model configurations were evaluated: baseline (accuracy=0.8794, F1-score=0.8691), feature selection (accuracy=0.8968, F1-score=0.8860), feature construction (accuracy=0.8980, F1-score=0.8872), and feature weighting (accuracy=0.8986, F1-score=0.8877). SHAP-based engineering yielded performance improvements, with feature weighting achieving the highest precision (0.9940). Key features (e.g., red blood cell count and chronic severity) contributed to predictions while maintaining interpretability.
Conclusion
The SHAP-based framework substantially improved the accuracy and transparency of appendix cancer predictions using LightGBM (F1-score=0.8877). This approach bridges the gap between predictive power and clinical interpretability, offering a scalable model for rare disease prediction. Future validation with real-world data is recommended to ensure generalizability.
2.Complete mouth rehabilitation with fixed implant-supported prosthesis in an edentulous maxilla using dental CAD-CAM technology
Jeong Eun HONG ; Hwa-Ryun CHA ; Ji-Won BANG ; Seong-A KIM ; Keun-Woo LEE ; Yong-Sang LEE ; Hee-Won JANG
The Journal of Korean Academy of Prosthodontics 2025;63(2):194-202
For patients with edentulous maxillae, creating a prosthetic treatment plan involves considering anatomical factors, aesthetics, the patient’s financial situation, and oral hygiene capabilities. In this case, CAD-CAM technology was used to accurately plan implant placements for a full arch fixed restoration based on the design of the final prosthesis. A customized surgical guide ensured precise implant placement and a provisional restoration was created using CAD-CAM. The definitive prosthesis was then created based on the second provisional restoration that has been previously used and adjusted by the patient. This approach achieved an excellent functional and aesthetic outcome, highlighting the benefits of digital approach and its potential for further clinical applications.
3.Full mouth rehabilitation of patient with excessively worn dentition from multiple factors: a case report
Jiwon HA ; Jai-Young KOAK ; Seong-Kyun KIM ; Ji-Man PARK
The Journal of Korean Academy of Prosthodontics 2025;63(2):154-163
Excessive wear of the teeth, which causes functional, aesthetic problems, or sensitivity symptoms, is referred to as pathological wear. If this leads to the collapse of occlusion, extensive restoration is necessary to restore function and aesthetics.When restoring pathologically worn dentition, it is essential to identify the cause of the wear before determining treatment plan to get a favorable prognosis. In this case, a patient exhibited severe tooth wear with decreased vertical dimension and clinical, radiographic examination, and medical history indicated the pathological wear caused by a combination of factors. Consequently, full-mouth rehabilitation was indicated and the vertical occlusal height was determined considering the appropriate restorative space. Based on the causes of the wear, the restoration method, materials, and occlusal pattern were selected and successfully restored to normal occlusal state through full-mouth rehabilitation with zirconia full-veneered crowns.
4.Biomechanics in terms of rotation angles and torques of implant-abutment screw tightening and loosening: Effects of implant types, contamination and sandblasting
Jiwoo LEE ; Seong-Kyun KIM ; Jai-Young KOAK ; Ji-Man PARK ; Jaejin CHO
The Journal of Korean Academy of Prosthodontics 2025;63(2):103-113
Purpose:
. The purpose of this study is to analyze the biomechanical differences in rotation angle-torque according to the type of implant and to compare the effects of contamination and sandblasting on the removal torque value (RTV) of abutment screws.
Materials and methods:
. For this study, an automated device for tightening and loosening implant screws was developed, and each 15 implant-abutment complexes of external and internal connection type were prepared, divided into three groups according to the surface treatment of the screw:control group (no treatment), experimental group-1 (artificial saliva contamination and chlorhexidine (CHX) rinsing), and experimental group-2 (artificial saliva contamination, CHX rinsing, and subsequent 50 µm Al 2 O 3 sandblasting). FirstRTV was measured for each group, followed by different post-treatment procedures for the screws, and then Second-RTV was measured. During the procedure, the removal torque value and rotation angle vs. time were recorded at a 20 data/s.A standardized protocol was followed for all the tightening and loosening procedures: screw was tightened with 30 Ncm torque and maintained for 5 s, and then rotated in the reverse direction until the torque value reached 0 Ncm. After 10min of rest period, the screws were loosened to initial point.
Results:
. Statistical analysis of measured data revealed that the internal connection type showed significantly higher First-RTV compared to the external connection type, however, no significant differences in Second-RTV were found. Both experimental groups 1and 2 showed a decrease in RTVs for both implant types, while the control group showed a decrease in RTV only for the internal type. The internal connection type required a significantly larger rotation angle during the tightening and loosening process.
Conclusion
. Within the limitations of this study, both artificial saliva contamination and CHX cleansing, as well as sandblasting, decreased RTV in both internal and external connection types. Internal connections were more susceptible to the effects of contaminants.
5.Implant-assisted removable partial denture restoration in a partially edentulous patient with a single remaining tooth:a case report
Ji Won KIM ; Ji-Won BANG ; Hwa-Ryun CHA ; Joo-Hyuk BANG ; Keun-Woo LEE ; Sun-Young YIM
The Journal of Korean Academy of Prosthodontics 2025;63(1):73-81
In cases of partially edentulous patients with insufficient remaining teeth, rotational movement of the denture occurs and prognosis of the remaining teeth is uncertain when restoring with a removable partial denture. Recently, implant-assisted removable partial dentures, where a small number of implants are placed and surveyed crowns are fabricated on the implants to be used as abutments, have been suggested. In this case, the patient had only one remaining tooth in the mandible and implants were placed in both posterior regions to be used as surveyed crowns to restore the patient with an implant-assisted removable partial denture. This approach improved the support, retention, and stability of the denture, resulting in functionally and aesthetically satisfactory outcomes.
6.Complete mouth rehabilitation using jaw motion tracking and facial scan: a case report
Jongmin KIM ; Jai-Young KOAK ; Seong-Kyun KIM ; Ji-Man PARK
The Journal of Korean Academy of Prosthodontics 2025;63(1):50-61
The occlusal collapse resulting from loss of posterior tooth support and attrition necessitates treatment aimed at restoring normal function and aesthetics.Particularly in cases where there is insufficient space for restoration, full mouth rehabilitation accompanied by increased vertical dimension is necessary. This case report presents a complete mouth rehabilitation of a patient with inadequate anterior restoration space due to loss of posterior tooth support, utilizing guided implant surgery, facial scan, virtual articulator, and jaw motion tracker.
7.Maxillary IARPD, mandibular fixed implant supported prostheses in patient with crossed occlusion: a case report
The Journal of Korean Academy of Prosthodontics 2025;63(1):40-49
The crossed occlusion is unstable, and for the treatment of such occlusal conditions, it is recommended to form a balance of occlusal force between the arch in contact with occlusal contact, to secure stable vertical support by symmetrically placing the implants in the posterior area, and it is necessary to improve the distorted occlusal plane, to have a regular check-up and to check whether the occlusal conditions are maintained stably after treatment. In this case, in order to resolve unstable occlusal condition in patient with crossed occlusion, the existing occlusal vertical dimension was maintained at the state of wearing the dentures, and the implant placement positions were planned based on the diagnostic waxup, and then the implants were placed using a surgical guides, and after the temporary prostheses stage, the final fixed prostheses were fabricated by incorporating the temporary prostheses form adapted by the patient to develop a stable vertical support, and finally the anterior maxillary region was restored with implant-supported removable partial denture. In this case, the patient adapted well without discomfort during the four-month follow-up and satisfactory aesthetic and functional clinical results were obtained, leading to this report.
8.Rapidly Growing Gastrointestinal Stromal Tumor on the Esophagus
Ji Hye PARK ; Sung Eun KIM ; Seun Ja PARK ; Moo In PARK ; Won MOON ; Jae Hyun KIM ; Kyoungwon JUNG ; Myung Hun LEE
The Korean Journal of Helicobacter and Upper Gastrointestinal Research 2025;25(1):64-69
Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms that mainly occur in the stomach and small intestine; those arising in the esophagus are rarer. A 54-year-old woman was referred to our hospital with a one-month history of dysphagia. Esophagogastroduodenoscopy (EGD), performed approximately five months earlier, had not revealed any specific findings. However, an EGD performed in our hospital showed the presence of a round, protruding lesion (approximately 40×30 mm in size), with a normal overlying mucosal surface, 35–39 cm from the upper incisor. Chest computed tomography (CT) revealed a large esophageal mass. Enucleation was performed on the esophageal mass, and a GIST was diagnosed using immunochemical staining. Imatinib mesylate administration was initiated two months postoperatively. The patient was stable, without any evident recurrence in the 8-month postoperative follow-up EGD and chest CT examinations. Therefore, physicians should consider that patients with worsening dysphagia may have an underlying organic condition, such as an acute increase in size of an esophageal GIST, even if recent examinations were unremarkable.
10.Association between acid-suppressive drugs and risk of psoriasis: retrospective study using Korean National Health Insurance Service-National Sample Cohort
Ji Hyun KIM ; Joon-hong MIN ; Young Woo JO ; Jae Woo KWON ; Young HER
The Korean Journal of Internal Medicine 2025;40(1):57-64
Background/Aims:
Psoriasis is a common inflammatory skin disorder following non-specific triggers. Involvement of immune system is widely accepted for pathogenesis studies have demonstrated importance of gut microbiota in pathogenesis of inflammatory skin diseases. Proton pump inhibitor (PPI) and histamine-2 receptor antagonist (H2RA) are acid-suppressive drugs widely used for acid related gastrointestinal diseases, and prolonged use has been associated with altered gut microbiota. This study aimed to investigate association between psoriasis and acid suppressing drugs in Korean population.
Methods:
This study was conducted with 3,662 patients diagnosed with psoriasis between 2002 and 2013 in NHIS-NSC. A total of 14,648 controls were matched at 1:4 based on sex, age, and gastrointestinal disease. ORs were estimated to determine the association between acid suppressing drug use and psoriasis.
Results:
Our study found a statistically significant association between the prolonged use of acid-suppressive drugs and the development of psoriasis in the Korean population. Specifically, patients with gastrointestinal diseases who used histamine-2 receptor antagonists (H2RA) or proton pump inhibitors (PPI) for extended periods exhibited a higher risk of developing psoriasis. The adjusted odds ratio for psoriasis was 1.89 (95% CI, 1.66–2.17) with long-term use, indicating a clear dose-response relationship.
Conclusions
Results from our study indicate that prolonged use of H2RA or PPI is associated with the risk of psoriasis among patients with gastrointestinal diseases in Korean population. The risk was increased in dose-response trend after adjusting for confounding variables. Clinicians should be aware of risks associated with prolonged use of acid suppressing drugs.

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