1.Key factors for successful eruption of the mandibular third molar after extraction of the mandibular second molar
Jung Jin PARK ; Yoonjeong NOH ; Yoon Jeong CHOI ; Jae Hyun PARK ; Ji Hyun LEE ; Chooryung Judi CHUNG ; Kyung-Ho KIM
The Korean Journal of Orthodontics 2025;55(2):154-163
		                        		
		                        			 Objective:
		                        			Extraction of the mandibular second molar (L7) and substitution by the mandibular third molar (L8) is an effective treatment option. This study aimed to evaluate spontaneously erupted L8 occlusion after L7 extraction, and identify the influencing factors.  
		                        		
		                        			Methods:
		                        			This study assessed 46 L8 from 28 patients using dental study models, panoramic radiographs, and lateral cephalograms obtained during L7 extraction (T1) and completion of L8 eruption (T2). At T2, samples were categorized as acceptable (A-group) or unacceptable (U-group) based on the American Board of Orthodontics index.L8 angulation and position, retromolar space, distance between the Xi point and mandibular first molar (L6), and Nolla stage were compared between the groups to identify the predictive factors for successful eruption.  
		                        		
		                        			Results:
		                        			At T2, 58.7% of L8 exhibited acceptable occlusion. Age at T1 was significantly higher in the U-group than that in the A-group. Angles ∠6-MnP and ∠8-MnP differed significantly between the groups at T2. Xi-L6 distance was considerably longer in the A-group than that in the U-group at T1 and T2. Younger age at extraction and Xi-L6 distance at T1 affected the acceptable occlusion. 
		                        		
		                        			Conclusions
		                        			Younger age at L7 extraction and adequate eruption space (Xi-L6 distance) appear to be the key factors for achieving acceptable L8 occlusion. 
		                        		
		                        		
		                        		
		                        	
2.Two Catastrophic Cases of Fecal Impaction in Patients with Neuropsychiatric Disorders
Yu Ra JANG ; Sang Jae NOH ; Ho LEE
Korean Journal of Legal Medicine 2025;49(2):46-50
		                        		
		                        			
		                        			 Fecal impaction (FI) is a potentially fatal condition characterized by the accumulation of large, hardened fecal masses in the large intestine, resulting in mechanical obstruction. This condition is commonly observed in older adults but can also affect younger populations, particularly patients with psychiatric conditions who face increased risk due to medication side effects, autonomic dysfunction, and inadequate bowel management. This report describes two forensic autopsy cases of fatal FI in patients with neuropsychiatric disorders. The first case involved a 52-year-old man with mild intellectual disability who had received long-term psychiatric treatment. Autopsy findings included marked colonic dilation (maximum diameter >10 cm), ischemic mucosal changes, and a large fecal mass (~2,200 g) obstructing the sigmoid and descending colon. The second case involved a 25-year-old man with severe intellectual disability. Autopsy revealed severe colonic dilation (maximum diameter of 12 cm), extensive FI along rectum and descending colon, and no evidence of alternative causes of death. In both cases, death was attributed to mechanical intestinal obstruction secondary to FI. These cases highlight the forensic significance of FI as a cause of sudden death in patients with neuropsychiatric disorders. Symptoms such as paradoxical diarrhea may be misinterpreted, and the inadvertent use of contraindicated medications (e.g., antidiarrheals) can worsen the condition, contributing to fatal outcomes. Furthermore, forensic evaluation must assess whether inadequate medical intervention or neglect played a role in the progression of FI. Early recognition, proactive bowel management, and interdisciplinary collaboration are critical to preventing fatal events in high-risk patients with neuropsychiatric disorders. 
		                        		
		                        		
		                        		
		                        	
3.Association of Intensive Endoscopic Burden with Esophageal Cancer Detection: A Nationwide Cohort Study
Yeunji LEE ; Eunyoung LEE ; Bumhee PARK ; Gil Ho LEE ; Sun Gyo LIM ; Sung Jae SHIN ; Choong-Kyun NOH ; Kee Myung LEE
Gut and Liver 2025;19(1):59-68
		                        		
		                        			 Background/Aims:
		                        			Early diagnosis of esophageal cancer (EC) remains challenging despite the increasing frequency of endoscopic screenings globally. The rapidly increasing number of endoscopic screenings performed over a certain period might influence diagnostic performance. This study evaluated the association between the number of endoscopic screenings and EC detection rates in a nationwide cohort. 
		                        		
		                        			Methods:
		                        			This retrospective population-based study used the Korean National Cancer Screening Program database, comprising 32,774,742 males and females aged ≥40 years between 2015and 2019. Negative binomial regression model and least-squares mean evaluation were used to assess the association between month of the year and EC detection rates. 
		                        		
		                        			Results:
		                        			This study enrolled 28,032,590 participants who underwent upper endoscopy. The number of participants in the fourth quarter (October to December: 10,923,142 [39.0%]) was 2.1 times higher than that in the first quarter (January to March: 5,085,087 [18.1%]); this trend continued for all 5 years. Contrarily, detection rates for EC in the fourth quarter (0.08/1,000 person) were half that in the first quarter (0.15/1,000 person). The odds of detecting EC were lowest in November; in 2015 the odds were 0.57 (95% confidence interval, 0.41 to 0.79; p=0.001) times lower and in 2016, they were 0.51 (95% confidence interval, 0.37 to 0.68; p<0.001) times lower compared to January. The predicted detection rates showed a decreasing trend toward the end of the year (p>0.05 for all). 
		                        		
		                        			Conclusions
		                        			The workload of endoscopists increased excessively with the rising number of endoscopies toward the end of the year, which was reflected by the decreased EC detection rates during this period. 
		                        		
		                        		
		                        		
		                        	
4.The Potential Role of the Rapid Urease Test with the Sweeping Method in the Gray Zone of the Urea Breath Test after Helicobacter pylori Eradication
Ji Hyun KIM ; Ji Min KIM ; Bumhee PARK ; Sun Gyo LIM ; Sung Jae SHIN ; Kee Myung LEE ; Gil Ho LEE ; Choong-Kyun NOH
Gut and Liver 2025;19(3):355-363
		                        		
		                        			 Background/Aims:
		                        			Although the urea breath test (UBT) is widely used as a representative monitoring test after Helicobacter pylori eradication, false-negative results can occur because of the gray zone related to its cutoff value. This study aimed to compare the diagnostic performances of the rapid urease test (RUT), the RUT with sweeping method, and the UBT, and to investigate the role of the sweeping method in the gray zone of UBT values. 
		                        		
		                        			Methods:
		                        			We retrospectively reviewed 216 patients who received standard first-line H. pylori eradication treatments (n=216). All participants underwent to testing using the sweeping method and UBT on the same day. The sensitivity, specificity, and accuracy were analyzed to compare the two methods. 
		                        		
		                        			Results:
		                        			The sensitivity (0.537 vs 0.806, p=0.002) and accuracy (0.843 vs 0.870, p=0.026) of the UBT were inferior to those of the sweeping method. A total of 31 individuals tested positive for H. pylori according to the UBT, whereas 54 individuals tested positive according to the sweeping method. In the group for which the gold standard definition indicated H. pylori positivity but UBT results were negative (n=31), all individuals had a UBT value under 2.5‰. In the multivariate logistic regression model, a UBT value of 1.4‰ to 2.5‰ increased the risk of false-negative results by 6.5 times (odds ratio, 6.5; 95% confidence interval, 2.077 to 20.288; p=0.001). 
		                        		
		                        			Conclusions
		                        			After H. pylori eradication, false-negative results can occur for individuals undergoing the UBT, primarily for values below the UBT cutoff. The RUT with the sweeping method can potentially help detect H. pylori in the gray zone of the UBT, improving diagnostic accuracy. 
		                        		
		                        		
		                        		
		                        	
5.Key factors for successful eruption of the mandibular third molar after extraction of the mandibular second molar
Jung Jin PARK ; Yoonjeong NOH ; Yoon Jeong CHOI ; Jae Hyun PARK ; Ji Hyun LEE ; Chooryung Judi CHUNG ; Kyung-Ho KIM
The Korean Journal of Orthodontics 2025;55(2):154-163
		                        		
		                        			 Objective:
		                        			Extraction of the mandibular second molar (L7) and substitution by the mandibular third molar (L8) is an effective treatment option. This study aimed to evaluate spontaneously erupted L8 occlusion after L7 extraction, and identify the influencing factors.  
		                        		
		                        			Methods:
		                        			This study assessed 46 L8 from 28 patients using dental study models, panoramic radiographs, and lateral cephalograms obtained during L7 extraction (T1) and completion of L8 eruption (T2). At T2, samples were categorized as acceptable (A-group) or unacceptable (U-group) based on the American Board of Orthodontics index.L8 angulation and position, retromolar space, distance between the Xi point and mandibular first molar (L6), and Nolla stage were compared between the groups to identify the predictive factors for successful eruption.  
		                        		
		                        			Results:
		                        			At T2, 58.7% of L8 exhibited acceptable occlusion. Age at T1 was significantly higher in the U-group than that in the A-group. Angles ∠6-MnP and ∠8-MnP differed significantly between the groups at T2. Xi-L6 distance was considerably longer in the A-group than that in the U-group at T1 and T2. Younger age at extraction and Xi-L6 distance at T1 affected the acceptable occlusion. 
		                        		
		                        			Conclusions
		                        			Younger age at L7 extraction and adequate eruption space (Xi-L6 distance) appear to be the key factors for achieving acceptable L8 occlusion. 
		                        		
		                        		
		                        		
		                        	
6.Key factors for successful eruption of the mandibular third molar after extraction of the mandibular second molar
Jung Jin PARK ; Yoonjeong NOH ; Yoon Jeong CHOI ; Jae Hyun PARK ; Ji Hyun LEE ; Chooryung Judi CHUNG ; Kyung-Ho KIM
The Korean Journal of Orthodontics 2025;55(2):154-163
		                        		
		                        			 Objective:
		                        			Extraction of the mandibular second molar (L7) and substitution by the mandibular third molar (L8) is an effective treatment option. This study aimed to evaluate spontaneously erupted L8 occlusion after L7 extraction, and identify the influencing factors.  
		                        		
		                        			Methods:
		                        			This study assessed 46 L8 from 28 patients using dental study models, panoramic radiographs, and lateral cephalograms obtained during L7 extraction (T1) and completion of L8 eruption (T2). At T2, samples were categorized as acceptable (A-group) or unacceptable (U-group) based on the American Board of Orthodontics index.L8 angulation and position, retromolar space, distance between the Xi point and mandibular first molar (L6), and Nolla stage were compared between the groups to identify the predictive factors for successful eruption.  
		                        		
		                        			Results:
		                        			At T2, 58.7% of L8 exhibited acceptable occlusion. Age at T1 was significantly higher in the U-group than that in the A-group. Angles ∠6-MnP and ∠8-MnP differed significantly between the groups at T2. Xi-L6 distance was considerably longer in the A-group than that in the U-group at T1 and T2. Younger age at extraction and Xi-L6 distance at T1 affected the acceptable occlusion. 
		                        		
		                        			Conclusions
		                        			Younger age at L7 extraction and adequate eruption space (Xi-L6 distance) appear to be the key factors for achieving acceptable L8 occlusion. 
		                        		
		                        		
		                        		
		                        	
7.Two Catastrophic Cases of Fecal Impaction in Patients with Neuropsychiatric Disorders
Yu Ra JANG ; Sang Jae NOH ; Ho LEE
Korean Journal of Legal Medicine 2025;49(2):46-50
		                        		
		                        			
		                        			 Fecal impaction (FI) is a potentially fatal condition characterized by the accumulation of large, hardened fecal masses in the large intestine, resulting in mechanical obstruction. This condition is commonly observed in older adults but can also affect younger populations, particularly patients with psychiatric conditions who face increased risk due to medication side effects, autonomic dysfunction, and inadequate bowel management. This report describes two forensic autopsy cases of fatal FI in patients with neuropsychiatric disorders. The first case involved a 52-year-old man with mild intellectual disability who had received long-term psychiatric treatment. Autopsy findings included marked colonic dilation (maximum diameter >10 cm), ischemic mucosal changes, and a large fecal mass (~2,200 g) obstructing the sigmoid and descending colon. The second case involved a 25-year-old man with severe intellectual disability. Autopsy revealed severe colonic dilation (maximum diameter of 12 cm), extensive FI along rectum and descending colon, and no evidence of alternative causes of death. In both cases, death was attributed to mechanical intestinal obstruction secondary to FI. These cases highlight the forensic significance of FI as a cause of sudden death in patients with neuropsychiatric disorders. Symptoms such as paradoxical diarrhea may be misinterpreted, and the inadvertent use of contraindicated medications (e.g., antidiarrheals) can worsen the condition, contributing to fatal outcomes. Furthermore, forensic evaluation must assess whether inadequate medical intervention or neglect played a role in the progression of FI. Early recognition, proactive bowel management, and interdisciplinary collaboration are critical to preventing fatal events in high-risk patients with neuropsychiatric disorders. 
		                        		
		                        		
		                        		
		                        	
8.Association of Intensive Endoscopic Burden with Esophageal Cancer Detection: A Nationwide Cohort Study
Yeunji LEE ; Eunyoung LEE ; Bumhee PARK ; Gil Ho LEE ; Sun Gyo LIM ; Sung Jae SHIN ; Choong-Kyun NOH ; Kee Myung LEE
Gut and Liver 2025;19(1):59-68
		                        		
		                        			 Background/Aims:
		                        			Early diagnosis of esophageal cancer (EC) remains challenging despite the increasing frequency of endoscopic screenings globally. The rapidly increasing number of endoscopic screenings performed over a certain period might influence diagnostic performance. This study evaluated the association between the number of endoscopic screenings and EC detection rates in a nationwide cohort. 
		                        		
		                        			Methods:
		                        			This retrospective population-based study used the Korean National Cancer Screening Program database, comprising 32,774,742 males and females aged ≥40 years between 2015and 2019. Negative binomial regression model and least-squares mean evaluation were used to assess the association between month of the year and EC detection rates. 
		                        		
		                        			Results:
		                        			This study enrolled 28,032,590 participants who underwent upper endoscopy. The number of participants in the fourth quarter (October to December: 10,923,142 [39.0%]) was 2.1 times higher than that in the first quarter (January to March: 5,085,087 [18.1%]); this trend continued for all 5 years. Contrarily, detection rates for EC in the fourth quarter (0.08/1,000 person) were half that in the first quarter (0.15/1,000 person). The odds of detecting EC were lowest in November; in 2015 the odds were 0.57 (95% confidence interval, 0.41 to 0.79; p=0.001) times lower and in 2016, they were 0.51 (95% confidence interval, 0.37 to 0.68; p<0.001) times lower compared to January. The predicted detection rates showed a decreasing trend toward the end of the year (p>0.05 for all). 
		                        		
		                        			Conclusions
		                        			The workload of endoscopists increased excessively with the rising number of endoscopies toward the end of the year, which was reflected by the decreased EC detection rates during this period. 
		                        		
		                        		
		                        		
		                        	
9.The Potential Role of the Rapid Urease Test with the Sweeping Method in the Gray Zone of the Urea Breath Test after Helicobacter pylori Eradication
Ji Hyun KIM ; Ji Min KIM ; Bumhee PARK ; Sun Gyo LIM ; Sung Jae SHIN ; Kee Myung LEE ; Gil Ho LEE ; Choong-Kyun NOH
Gut and Liver 2025;19(3):355-363
		                        		
		                        			 Background/Aims:
		                        			Although the urea breath test (UBT) is widely used as a representative monitoring test after Helicobacter pylori eradication, false-negative results can occur because of the gray zone related to its cutoff value. This study aimed to compare the diagnostic performances of the rapid urease test (RUT), the RUT with sweeping method, and the UBT, and to investigate the role of the sweeping method in the gray zone of UBT values. 
		                        		
		                        			Methods:
		                        			We retrospectively reviewed 216 patients who received standard first-line H. pylori eradication treatments (n=216). All participants underwent to testing using the sweeping method and UBT on the same day. The sensitivity, specificity, and accuracy were analyzed to compare the two methods. 
		                        		
		                        			Results:
		                        			The sensitivity (0.537 vs 0.806, p=0.002) and accuracy (0.843 vs 0.870, p=0.026) of the UBT were inferior to those of the sweeping method. A total of 31 individuals tested positive for H. pylori according to the UBT, whereas 54 individuals tested positive according to the sweeping method. In the group for which the gold standard definition indicated H. pylori positivity but UBT results were negative (n=31), all individuals had a UBT value under 2.5‰. In the multivariate logistic regression model, a UBT value of 1.4‰ to 2.5‰ increased the risk of false-negative results by 6.5 times (odds ratio, 6.5; 95% confidence interval, 2.077 to 20.288; p=0.001). 
		                        		
		                        			Conclusions
		                        			After H. pylori eradication, false-negative results can occur for individuals undergoing the UBT, primarily for values below the UBT cutoff. The RUT with the sweeping method can potentially help detect H. pylori in the gray zone of the UBT, improving diagnostic accuracy. 
		                        		
		                        		
		                        		
		                        	
10.Association of Intensive Endoscopic Burden with Esophageal Cancer Detection: A Nationwide Cohort Study
Yeunji LEE ; Eunyoung LEE ; Bumhee PARK ; Gil Ho LEE ; Sun Gyo LIM ; Sung Jae SHIN ; Choong-Kyun NOH ; Kee Myung LEE
Gut and Liver 2025;19(1):59-68
		                        		
		                        			 Background/Aims:
		                        			Early diagnosis of esophageal cancer (EC) remains challenging despite the increasing frequency of endoscopic screenings globally. The rapidly increasing number of endoscopic screenings performed over a certain period might influence diagnostic performance. This study evaluated the association between the number of endoscopic screenings and EC detection rates in a nationwide cohort. 
		                        		
		                        			Methods:
		                        			This retrospective population-based study used the Korean National Cancer Screening Program database, comprising 32,774,742 males and females aged ≥40 years between 2015and 2019. Negative binomial regression model and least-squares mean evaluation were used to assess the association between month of the year and EC detection rates. 
		                        		
		                        			Results:
		                        			This study enrolled 28,032,590 participants who underwent upper endoscopy. The number of participants in the fourth quarter (October to December: 10,923,142 [39.0%]) was 2.1 times higher than that in the first quarter (January to March: 5,085,087 [18.1%]); this trend continued for all 5 years. Contrarily, detection rates for EC in the fourth quarter (0.08/1,000 person) were half that in the first quarter (0.15/1,000 person). The odds of detecting EC were lowest in November; in 2015 the odds were 0.57 (95% confidence interval, 0.41 to 0.79; p=0.001) times lower and in 2016, they were 0.51 (95% confidence interval, 0.37 to 0.68; p<0.001) times lower compared to January. The predicted detection rates showed a decreasing trend toward the end of the year (p>0.05 for all). 
		                        		
		                        			Conclusions
		                        			The workload of endoscopists increased excessively with the rising number of endoscopies toward the end of the year, which was reflected by the decreased EC detection rates during this period. 
		                        		
		                        		
		                        		
		                        	
            
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