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.

Background: s/Aims: While large-for-size syndrome is uncommon in liver transplantation (LT), it can result in fatal outcome. To prevent such fatality, we manufactured 3D-printed intra-abdominal cavity replicas to provide intuitive understanding of the sizes of the graft and the patient’s abdomen in patients with small body size between July 2020 and February 2022. Methods: Clinical outcomes were compared between patients using our 3D model during LT, and patients who underwent LT without 3D model by using 1 : 5 ratio propensity score-matched analysis. Results: After matching, a total of 20 patients using 3D-printed abdominal cavity model and 100 patients of the control group were included in this study. There were no significant differences in 30-day postoperative complication (50.0% vs. 64.0%, p = 0.356) and the incidence of large-for-size syndrome (0% vs. 7%, p = 0.599). Overall survival of the 3D-printed group was similar to that of the control group (p = 0.665), but graft survival was significantly superior in the 3D-printed group, compared to the control group (p = 0.034). Conclusions Since it showed better graft survival, as well as low cost and short production time, our 3D-printing protocol can be a feasible option for patients with small abdominal cavity to prevent large-for-size syndrome after LT.

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.

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.

Purpose: This study evaluated the postoperative quality of life (QoL) after various types of gastrectomy for gastric cancer. Materials and Methods: A multicenter prospective observational study was conducted in Korea using the Korean Quality of Life in Stomach Cancer Patients Study (KOQUSS)-40, a new QoL assessment tool focusing on postgastrectomy syndrome. Overall, 496 patients with gastric cancer were enrolled, and QoL was assessed at 5 time points: preoperatively and at 1, 3, 6, and 12 months after surgery. Results: Distal gastrectomy (DG) and pylorus-preserving gastrectomy (PPG) showed significantly better outcomes than total gastrectomy (TG) and proximal gastrectomy (PG) with regard to total score, indigestion, and dysphagia. DG, PPG, and TG also showed significantly better outcomes than PG in terms of dumping syndrome and worry about cancer. Postoperative QoL did not differ significantly according to anastomosis type in DG, except for Billroth I anastomosis, which achieved better bowel habit change scores than the others. No domains differed significantly when comparing double tract reconstruction and esophagogastrostomy after PG. The total QoL score correlated significantly with postoperative body weight loss (more than 10%) and extent of resection (P<0.05 for both).Reflux as assessed by KOQUSS-40 did not correlate significantly with reflux observed on gastroscopy 1 year postoperatively (P=0.064). Conclusions Our prospective observation using KOQUSS-40 revealed that DG and PPG lead to better QoL than TG and PG. Further study is needed to compare postoperative QoL according to anastomosis type in DG and PG.

Background: s/Aims: While large-for-size syndrome is uncommon in liver transplantation (LT), it can result in fatal outcome. To prevent such fatality, we manufactured 3D-printed intra-abdominal cavity replicas to provide intuitive understanding of the sizes of the graft and the patient’s abdomen in patients with small body size between July 2020 and February 2022. Methods: Clinical outcomes were compared between patients using our 3D model during LT, and patients who underwent LT without 3D model by using 1 : 5 ratio propensity score-matched analysis. Results: After matching, a total of 20 patients using 3D-printed abdominal cavity model and 100 patients of the control group were included in this study. There were no significant differences in 30-day postoperative complication (50.0% vs. 64.0%, p = 0.356) and the incidence of large-for-size syndrome (0% vs. 7%, p = 0.599). Overall survival of the 3D-printed group was similar to that of the control group (p = 0.665), but graft survival was significantly superior in the 3D-printed group, compared to the control group (p = 0.034). Conclusions Since it showed better graft survival, as well as low cost and short production time, our 3D-printing protocol can be a feasible option for patients with small abdominal cavity to prevent large-for-size syndrome after LT.

Purpose: This study evaluated the postoperative quality of life (QoL) after various types of gastrectomy for gastric cancer. Materials and Methods: A multicenter prospective observational study was conducted in Korea using the Korean Quality of Life in Stomach Cancer Patients Study (KOQUSS)-40, a new QoL assessment tool focusing on postgastrectomy syndrome. Overall, 496 patients with gastric cancer were enrolled, and QoL was assessed at 5 time points: preoperatively and at 1, 3, 6, and 12 months after surgery. Results: Distal gastrectomy (DG) and pylorus-preserving gastrectomy (PPG) showed significantly better outcomes than total gastrectomy (TG) and proximal gastrectomy (PG) with regard to total score, indigestion, and dysphagia. DG, PPG, and TG also showed significantly better outcomes than PG in terms of dumping syndrome and worry about cancer. Postoperative QoL did not differ significantly according to anastomosis type in DG, except for Billroth I anastomosis, which achieved better bowel habit change scores than the others. No domains differed significantly when comparing double tract reconstruction and esophagogastrostomy after PG. The total QoL score correlated significantly with postoperative body weight loss (more than 10%) and extent of resection (P<0.05 for both).Reflux as assessed by KOQUSS-40 did not correlate significantly with reflux observed on gastroscopy 1 year postoperatively (P=0.064). Conclusions Our prospective observation using KOQUSS-40 revealed that DG and PPG lead to better QoL than TG and PG. Further study is needed to compare postoperative QoL according to anastomosis type in DG and PG.

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.