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.

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.

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.

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.

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.

Upper limb amputation leads to significant physical and psychosocial burden; however, it remains underrepresented in global epidemiological and rehabilitation studies. This study aimed to systematically review the global epidemiological data on upper limb amputation, focusing on its prevalence, incidence, anatomical levels, and etiology. According to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a comprehensive literature search was conducted using PubMed, Embase, Cochrane Library, and Regional Information Sharing Systems (up to May 2023). Two authors independently selected the studies, assessed their methodological quality, and summarized the evidence. Nineteen studies were finally included in this study. The prevalence of major upper limb amputation was higher in individuals with disabilities than in the general population. The prevalence in general population was 11.6 per 100,000 adults between 2006 and 2008 in Norway, whereas the prevalence in individuals with disabilities was 6.9 per 1,000 individuals in 2011 and increased to 11.3 per 1,000 individuals in 2020 in South Korea. The incidence rates were generally higher in the occupational population than in the general population. Below-elbow amputation was consistently the most common major amputation level reported. Although traumatic causes were predominant, medical conditions substantially contributed to upper limb impairment among individuals with disabilities. Upper limb amputation presents significant global variations in prevalence, incidence, anatomical level, and cause. The scarcity of standardized, disaggregated data limits effective planning for prosthetic services and rehabilitation. Future studies should prioritize comprehensive data collection to support equitable healthcare delivery and inform prosthetic innovation.

Background: Although patients with non-traumatic spinal cord injury (NTSCI) have distinct epidemiological characteristics compared to those with traumatic spinal cord injury, no previous study has reported the incidence of NTSCI on a national scale in Korea.In this study, we examined the trend in incidence of NTSCI in Korea and described the epidemiological characteristics of patients with NTSCI using nationwide insurance data. Methods: National Health Insurance Service data were reviewed for the period from 2007 to 2020. The International Classification of Diseases, 10th revision, was used to identify patients with NTSCI. Inpatients with newly diagnosed NTSCI on their first admission during the study period were included. Crude incidence was calculated using the annual number of NTSCI cases divided by the mid-year population estimates. Age-specific incidence was calculated by dividing the number of cases in 10-year age groups by the total number of individuals in that age group. Age-adjusted incidence was calculated using direct standardization. Annual percentage changes were calculated using Joinpoint regression analysis. The Cochrane-Armitage trend test was conducted to examine the trends of NTSCI incidence according to the types or etiologies of NTSCI. Results: The age-adjusted incidence of NTSCI increased continuously from 24.11 per million in 2007 to 39.83 per million in 2020, with a significant annual percentage change (4.93%, P < 0.05). The age-specific incidence for those in their 70s and 80s or older was the highest and rapidly increased from 2007 to 2020. According to the types of paralysis in NTSCI, the proportion of tetraplegia decreased, whereas those of paraplegia and cauda equina increased significantly from 2007 to 2020. The proportion of degenerative diseases was the largest among all etiologies and increased significantly during the study period. Conclusion The annual incidence of NTSCI in Korea is increasing significantly, particularly among older adults. As Korea is one of the countries with most rapidly aging population in the world, these results have significant implications, indicating that preventive strategies and sufficient rehabilitation medical services are warranted for the population of older adults.

This review describes the incidence rates and trends of traumatic spinal cord injuries (TSCI) and non-traumatic spinal cord injuries (NTSCI) in South Korea. The incidence of NTSCI has increased more rapidly than that of TSCI in recent years. In 2007, TSCI was more common, but by 2020, NTSCI had surpassed TSCI, particularly in older individuals. While men have a higher incidence of both TSCI and NTSCI, the incidence difference by sex is greater in TSCI.The incidence rates of both TSCI and NTSCI are higher in older individuals, particularly those in their 70s and 80s. For TSCI, falls and traffic accidents are the most common causes, with falls being more prevalent in older adults. Cervical SCIs are the most common TSCI, especially in high-income countries like South Korea. Patients with NTSCI predominantly display paraplegia, which is usually associated with non-traumatic causes such as degenerative disorders and tumors. Higher rates of tetraplegia and paraplegia are observed with TSCI and NTSCI, respectively. The neurological levels of injury also differ between TSCI and NTSCI. Overall, SCIs are a growing concern in South Korea and there is a need for targeted interventions for their management and prevention, especially in older age groups.

Spinal cord injury (SCI) has been recognized as a medically complex and life-disrupting condition. As the aging of the population accelerates, the trend of SCI has changed. This review aimed to provide comprehensive statistics and recent epidemiological changes in SCI and rehabilitation in Korea. All three insurance databases (National Health Insurance Service [NHIS], automobile insurance [AUI], and industrial accident compensation insurance [IACI]) were considered. These nationwide databases provide data on the current trends in term of incidence, etiology, and rehabilitation of SCI. Traumatic spinal cord injury (TSCI) was more frequent among the elderly in the NHIS compared to working age individuals in the AUI and IACI. In all three trauma-related insurance databases, male with TSCI outnumbered female. TSCI incidence per year was approximately 17 times higher among males than females, on average, in IACI. In all three insurances, the cervical level of TSCI was the most frequent. Although the ratio of SCI patients receiving rehabilitation treatment at primary and secondary hospitals increased for nine years, the increase in training on activities of daily living (ADL training) was found to be relatively small. This review provides a broader and comprehensive understanding of the incidence, etiology, and rehabilitation treatment of SCI in Korea.

Background: To examine the incidence of traumatic spinal cord injury (TSCI) from all etiologies, we measured and compared the incidence of TSCI from three national or quasinational databases in South Korea, namely, the National Health Insurance Service (NHIS), automobile insurance (AUI), and Industrial Accident Compensation Insurance (IACI). Methods: We reviewed patients with TSCI reported in the NHIS database between 2009 and 2018, and in the AUI and IACI databases between 2014 and 2018. TSCI patients were defined as those first admitted to the hospital with a diagnosis of TSCI according to the International Classification of Diseases (10th revision) criteria. Age-adjusted incidence was calculated using direct standardization using the 2005 South Korean population or the 2000 US population as the standard population. The annual percentage changes (APC) of TSCI incidence were calculated. The Cochrane–Armitage trend test was performed according to the injured body region. Results: In the NHIS database, age-adjusted TSCI incidence using the Korean standard population increased significantly from 2009 to 2018 (from 33.73 per million in 2009 to 38.14 per million in 2018, APC = 1.2%, P = 0.014). Contrarily, age-adjusted incidence in the AUI database significantly decreased from 13.88 per million in 2014 to 11.57 per million in 2018 (APC = – 5.1%, P = 0.009). In the IACI database, the age-adjusted incidence showed no significant difference, while crude incidence showed a significant increase (from 22.02 per million in 2014 to 28.92 per million in 2018, APC = 6.1%, P = 0.038). According to the age group, all the three databases showed high incidences of TSCI in those in their 60s and 70s or older. Among those in their 70s or older, the incidence of TSCI increased dramatically in the NHIS and IACI databases, while no significant trend was found in AUI database. In 2018, the number of TSCI patients was the highest among those over 70 years of age in the NHIS, whereas among those in their 50s were the highest in both AUI and IACI. The proportion of patients with cervical spinal cord injury was the most common in all these databases. Conclusions The differences in trends in the incidence of TSCI may be due to the different etiologies and different characteristics of subjects depending on insurance type. These results imply the need for tailored medical strategies for the different injury mechanisms represented by three national insurance services in South Korea.