Analysis of the incidence of dementia in complete edentulous patients using the National Health Insurance Service-Elderly Cohort Database (NHIS-ECD) / 대한치과보철학회지

Purpose@#To investigate the relationship between dementia and complete tooth loss on both sides or one side using large demographic data. @*Materials and methods@#A retrospective cohort study was designed using the National Health Insurance Service-Elderly Cohort Database (NHIS-ECD) which was established for people over the age of 60. The experimental group was the complete edentulous cohort, which had a history of treatment for national health insurance covered complete denture on both sides or one side from July 1, 2012 to December 31, 2013. And the control group was the dentulous cohort, which had a history of conservative dental treatment for the same period. All subjects had no history of diagnosis or treatment of dementia during this time. These cohorts were matched 1:1 by age, gender, and place of residence according to the propensity score matching method. Then the incidence of dementia was compared between these cohorts. @*Results@#Compared with those groups, the incidence of dementia was significantly higher in the experimental group (12.13%) than in the control group (9.74%) (P<.05). No clear association between other factors has been identified. @*Conclusion@#The analysis of large-scale demographic data shows that the incidence of dementia is high in complete edentulous patients on both sides or one side.

Incidentally Found Intramuscular Hemangioma, Mimicking Traumatic Hematoma after Military Training: A Case Report / 대한신경손상학회지

This case report showed a young soldier complained of low back pain during military training. Intramuscular hematoma accompanied by the lumbar compression fracture was observed in computed tomography. However, the possibility of intramuscular tumors could not be ruled out through additional examinations, and thus surgically removed, and was diagnosed as cavernous hemangioma. This report is a rare and instructive case in which a hemangioma mimicked bleeding with the lumbar fracture.

Repairment of abutment and abutment screw fracture in implant prosthesis: A case report / 대한치과보철학회지

Dental implants are an effective and predictable treatment for restoration of missing teeth. However, as the use of implants increases, complications are also increasing. The mechanical complications are not only highly frequent, but also increasing as life span of an implant increases, thus, solutions should be prepared. In this report, we will present a case dealing with abutment fracture and abutment screw fracture which are the most common mechanical complication of the implant, focusing on preserving and reusing existing components by reconstructing only the damaged parts.

The socioeconomic impact of Korean dental health insurance policy on the elderly: a nationwide cohort study in South Korea

PURPOSE: The purpose of this retrospective study was to investigate the relationships of types of dental insurance coverage in Korea with sociodemographic characteristics and the prevalence of systemic and oral diseases, as well as to evaluate the socioeconomic impact of Korean dental insurance policies. METHODS: Sample cohort data from 2006 to 2015 were obtained from the National Health Insurance Service. Patients were divided into 2 groups. The exposed group comprised patients who received insurance benefits for complete dentures, removable partial dentures, and implant care, while the control group comprised patients who did not receive these benefits. The type of insurance coverage and the prevalence of systemic and oral diseases were compared between the 2 groups. RESULTS: Patients who received benefits in the form of complete dentures, removable partial dentures, and implants had similar sociodemographic characteristics in terms of sex, age, income quintile, and type of insurance coverage to the control group. The prevalence of hypertension, anemia, renal disease, rheumatoid arthritis, osteoporosis, asthma, and cerebral infarction was higher in the exposed group than in the control group (P<0.05). The prevalence of periodontal diseases and dental caries was also higher in the exposed group. CONCLUSIONS: Korean dental health insurance policy has been beneficial for the medical expenses of low-income and elderly people suffering from a cost burden due to systemic diseases. However, since there is a tendency to avoid invasive interventions in older patients due to the high risk of systemic diseases, insurance coverage of dentures may be more helpful from a socioeconomic perspective than coverage of dental implant treatments.

Progression of Ossification of the Posterior Longitudinal Ligament after Cervical Total Disc Replacement / 대한신경손상학회지

OBJECTIVE: Total disc replacement (TDR) is frequently performed anterior approaching method for the patients diagnosed with cervical disc herniation. This study aimed to assess the degree of ossification of the posterior longitudinal ligament (OPLL) progression after cervical TDR. METHODS: Twenty-two male soldiers who underwent cervical TDR surgery from 2009 to 2016 and were followed-up for more than 12 months were enrolled. The enrolled patients were classified as; 1) patients with pre-existing OPLL and without; and 2) patient showing progression of OPLL or not. RESULTS: Twenty-two men were included in the analysis. The mean follow-up period from the surgery was 41.4 months (range, 12–114 months). The mean age of all patients was 40.7 years (range, 31–52 years). TDR-only was used in 7 cases, and the hybrid surgery (TDR+ACDF) was used in 15 cases. The incidence of progression or newly development of OPLL was significantly higher in pre-existing OPLL group (p=0.01). In 11 cases showing the progression of the OPLL, the mean size of OPLL progression was 4.16 mm (range, 0.34–18.87 mm) in the longitudinal height and 1.57 mm (range, 0.54–3.91 mm) in thickness. CONCLUSION: The progression of OPLL after cervical TDR was more frequent in patients with pre-existing OPLL than in patients without OPLL. Even though TDR is a major alternative to the treatment of cervical lesions to preserve vertebral segmental motion, careful attention should be paid to whether TDR should be used in patients with OPLL and this should be fully explained to the patient.

The Effect of Fibronectin-Immobilized Microgrooved Titanium Substrata on Cell Proliferation and Expression of Genes and Proteins in Human Gingival Fibroblasts

BACKGROUND: We aimed to determine the effect of fibronectin (FN)-immobilized microgrooved titanium (Ti) on human gingival fibroblast proliferation, gene expression and protein expression. METHODS: Photolithography was used to fabricate the microgrooved Ti, and amine funtionalization (silanization) was used for FN immobilization on titanium surfaces. Cell proliferation, gene expression and protein expression were analyzed, followed by multiple regression analysis for determining the influential factors on cell proliferation. RESULTS: FN-immobilized microgrooved Ti significantly enhanced the fibroblast proliferation in various timelines of culture, among which a burst of fivefold increase is induced at 96 h of culture compared to that on the control smooth Ti. We suggest a presence of the synergistic promotion effect of microgrooves and FN immobilization on fibroblast proliferation. Through a series of analyses on the expression of various genes and proteins involved in cell adhesion and proliferation, cyclin-dependent kinase 6, cyclin D1, integrin α5, oncogene c-Src, osteonectin, paxillin and talin-2 were determined as influential factors on promoting fibroblast proliferation induced by FN-immobilized microgrooved Ti. CONCLUSION: FN-immobilized microgrooved Ti can act as an effective surface for enhancing fibroblast proliferation, and can be used for promoting soft tissue response on the connective tissue attachment zone of biomaterial surfaces.

Analysis of longevity and success rate of fixed, removable, and implant prostheses treated in Korea / 대한치과보철학회지

PURPOSE: The purpose of this study is to analyze the factors affecting the longevity of failed prosthesis and the success rate of the prosthesis based on the data evaluated with the newly developed Korean Academy of Prosthodontics (KAP) criteria. MATERIALS AND METHODS: Evaluation was performed in the restored prosthesis for patients who visited the prosthodontics department of the 13 dental university hospitals and general hospitals. The status of the prosthesis was classified into four categories: Good, Fair, Bad, Worst. The success was recorded if only the category was classified in ‘good’. The mean duration of failed prostheses and the success rate through Kaplan-Meier method were analyzed. RESULTS: A total of 1,804 cases of prosthesis were evaluated: 810 cases of fixed dental prostheses (FDP), 519 cases of Removable Dental Prostheses (RDP), and 475 cases of implant prosthesis. The mean duration of failed FDP was 11.41 ± 0.30 years and the median was 10 years. The mean duration of failed RDP was 8.18 ± 0.29 years and the median was 7 years. The mean duration of failed implant prosthesis was 7.99 ± 0.30 years and the median was 7 years. The factors related to the failure were as follows: number of units, abutments, abutments treated with root canal, and plaque index in FDPs; treated and opposing dentition in RDPs; the number of implants, duration of use, and plaque index in implant prostheses. CONCLUSION: The average duration of failed prosthesis was 11.41 years for FDPs, 8.18 years for RDPs, and 7.99 years for implant prosthesis, according to the evaluation with newly developed KAP criteria.

Overdentures using newly designed metal ball attachment containing predetermined gap with stress breakers / 대한치과보철학회지

Several types of attachments have been used for implant supported and/or retained overdentures. Locator is one of the stud type attachments and it has been generally used. However, the colored matrix is resilient and vulnerable to wear, so frequent post-insertion maintenance is needed. To solve this problem, it is necessary to introduce innovative attachment system. Overdentures using Air Gap attachment (AGA) has improved masticatory function and facial esthetics. AGA is made of metal, so it could be more resistant to wear or friction than the other resilient attachments. Nevertheless, AGA plays a role in stress breakers because it allows movement during denture movement with predetermined gap. In addition, both pre-existing implants and natural teeth were successfully used for connection of AGA. AGA could replace other unsplinted type of attachments. Overdentures using AGA could provide satisfactory result in terms of function, esthetics and retention. However, long term follow up is needed.

Mechanical and biological complication rates of the modified lateral-screw-retained implant prosthesis in the posterior region: an alternative to the conventional Implant prosthetic system

PURPOSE: The modified lateral-screw-retained implant prosthesis (LSP) is designed to combine the advantages of screw- and cement-retained implant prostheses. This retrospective study evaluated the mechanical and biological complication rates of implant-supported single crowns (ISSCs) inserted with the modified LSP in the posterior region, and determined how these complication rates are affected by clinical factors. MATERIALS AND METHODS: Mechanical complications (i.e., lateral screw loosening [LSL], abutment screw loosening, lateral screw fracture, and ceramic fracture) and biological complications (i.e., peri-implant mucositis [PM] and peri-implantitis) were identified from the patients' treatment records, clinical photographs, periapical radiographs, panoramic radiographs, and clinical indices. The correlations between complication rates and the following clinical factors were determined: gender, age, position in the jaw, placement location, functional duration, clinical crown-to-implant length ratio, crown height space, and the use of a submerged or nonsubmerged placement procedure. RESULTS: Mechanical and biological complications were present in 25 of 73 ISSCs with the modified LSP. LSL (n=11) and PM (n=11) were the most common complications. The incidence of mechanical complications was significantly related to gender (P=.018). The other clinical factors were not significantly associated with mechanical and biological complication rates. CONCLUSION: Within the limitations of this study, the incidence of mechanical and biological complications in the posterior region was similar for both modified LSP and conventional implant prosthetic systems. In addition, the modified LSP is amenable to maintenance care, which facilitates the prevention and treatment of mechanical and biological complications.

Clinical cases of implant-supported fixed dental prosthesis using modified lingual screw system (T-screw system) / 대한치과보철학회지

The implant prosthesis can be divided into the screw retained prosthesis and cement retained prosthesis. Each type has advantages as well as disadvantages which is unfavorable to maintain the implants. To overcome these drawbacks, T-screw system was developed. T-screw system which utilizes a lingual direction of the screw to retain the implant prosthesis, has advantages of retrievability of the prosthesis, passive fit, and possibility to form esthetic and functional occlusal surface. The prior prosthesis which utilized horizontal screws had difficulty in fabrication especially in the case of multiple units, and also limited use with all-ceramic prosthesis. In this case, fabricating the implant prosthesis by using the T-screw system showed superior results in easy maintenance, esthetics, and also functions. In addition, we are to report the method of using the T-screw system in implant prosthesis, such as multiple units of implant prosthesis and all ceramic prosthesis.

Korea Academy of Prosthodontics criteria for longevity studies of dental prostheses / 대한치과보철학회지

PURPOSE: The most important factor in longevity studies of dental prostheses is objective and consistent evaluation of the prosthesis. The Korean Academy of Prosthodontics suggested developing a standardized method for longevity studies of dental prostheses. The purpose of this study is to evaluate previously-used criteria and to develop new criteria, in the form of a procedure flowchart and an evaluation sheet. These new criteria may be able to provide a unified standard for future longevity studies of dental prostheses. MATERIALS AND METHODS: A literature review was performed about the evaluation of dental prostheses. Taking into account the strengths and weaknesses of previously used criteria, a novel, intuitive and objective method was developed for assessment of dental prostheses. Then, a pilot survey was performed with the newly developed flowchart and evaluation sheet to determine problems and implement possible improvements. RESULTS: Thirty cases of fixed dental prosthesis (FDP), 25 cases of removable dental prosthesis (RDP), and 13 cases of implant supported prosthesis (ISP) were evaluated. The average life expectancy estimate was 12.82 years for FDP, 5.96 years for RDP, and 4.82 years for ISP with Kaplan-Meier survival analysis. Additionally, possible improvements discovered by the pilot survey were reflected in the flowchart and evaluation sheet. CONCLUSION: The newly developed KAP criteria, flowchart and evaluation sheet enabled objective and consistent results in trial longevity studies of dental prostheses. It is expected that future studies will not only use the KAP criteria but also further improvement will be made on them.

Effect of microgrooves and fibronectin conjugation on the osteoblast marker gene expression and differentiation

PURPOSE: To determine the effect of fibronectin (FN)-conjugated, microgrooved titanium (Ti) on osteoblast differentiation and gene expression in human bone marrow-derived mesenchymal stem cells (MSCs). MATERIALS AND METHODS: Photolithography was used to fabricate the microgrooved Ti, and amine functionalization (silanization) was used to immobilize fibronectin on the titanium surfaces. Osteoblast differentiation and osteoblast marker gene expression were analyzed by means of alkaline phosphatase activity assay, extracellular calcium deposition assay, and quantitative real-time PCR. RESULTS: The conjugation of fibronectin on Ti significantly increased osteoblast differentiation in MSCs compared with non-conjugated Ti substrates. On the extracellular calcium deposition assays of MSCs at 21 days, an approximately two-fold increase in calcium concentration was observed on the etched 60-microm-wide/10-microm-deep microgrooved surface with fibronectin (E60/10FN) compared with the same surface without fibronectin (E60/10), and a more than four-fold increase in calcium concentration was observed on E60/10FN compared with the non-etched control (NE0) and etched control (E0) surfaces. Through a series of analyses to determine the expression of osteoblast marker genes, a significant increase in all the marker genes except type I collagen alpha1 mRNA was seen with E60/10FN more than with any of the other groups, as compared with NE0. CONCLUSION: The FN-conjugated, microgrooved Ti substrate can provide an effective surface to promote osteoblast differentiation and osteoblast marker gene expression in MSCs.

Identification of genomic regions associated with piglet survival and mortality / 동물의과학연구지

One of the major problems in the modern pig industry is infectious disease. Susceptibility to infectious diseases is influenced by both constitutional (e.g. genotype, age, gender, and reproductive status) and environmental factors (e.g. nutrition, management, infections, and other forms of stress). Genetic variations within individual animals or herds can cause differences in the execution of immune functions against infectious agents in domestic pigs. The objectives of the present study were to identify genetic factor(s) responsible for piglet survival and mortality under commercial field conditions with infectious diseases as well as determine QTL regions for immune capacity in a pig reference family. Sex ratio was examined between normal grown and presumed dead groups of F2 animals generated by Korean native pigs (KNP) and Yorkshire (YS) breeds. The ratio of males was significantly higher in the presumed dead group than in the normal grown group. In order to study genetic factors associated with presumed mortality under disease outbreak, allelic frequencies of 239 single nucleotide polymorphisms (SNPs) were compared between normal grown and presumed dead groups. Exactly 22 SNPs showed significant differences in their allelic frequencies between the two groups, and four of them were validated with another commercial population divided by normal and emaciated pigs. Furthermore, the relationships between 239 SNPs and immune-related traits were studied. These results demonstrate that identification of genetic components of animal immune systems and susceptibility to infectious diseases is possible and will be useful to improve disease resistance in individuals as well as in breeding programs.

Development of implant loading device for animal study about various loading protocol: a pilot study

PURPOSE: The aims of this pilot study were to introduce implant loading devices designed for animal study and to evaluate the validity of the load transmission ability of the loading devices. MATERIALS AND METHODS: Implant loading devices were specially designed and fabricated with two implant abutments and cast metal bars, and orthodontic expansion screw. In six Beagles, all premolars were extracted and two implants were placed in each side of the mandibles. The loading device was inserted two weeks after the implant placement. According to the loading protocol, the load was applied to the implants with different time and method,simulating early, progressive, and delayed loading. The implants were clinically evaluated and the loading devices were removed and replaced to the master cast, followed by stress-strain analysis. Descriptive statistics of remained strain (microepsilon) was evaluated after repeating three cycles of the loading device activation. Statistic analysis was performed using nonparametric, independent t-test with 5% significance level and Friedman's test was also used for verification. RESULTS: The loading devices were in good action. However, four implants in three Beagles showed loss of osseointegration. In stress-strain analysis, loading devices showed similar amount of increase in the remained strain after applying 1-unit load for three times. CONCLUSION: Specialized design of the implant loading device was introduced. The loading device applied similar amount of loads near the implant after each 1-unit loading. However, the direction of the loads was not parallel to the long axis of the implants as predicted before the study.

The Relationship Between Interleukin 1beta Gene Polymorphism and Renal Involvement in Henoch-Schonlein Purpura

PURPOSE: High interleukin-1 beta(IL-1beta) expression in the skin biopsy specimens of patients with Henoch-Schonlein Purpura(HSP) has been observed. We examined IL-1beta gene polymorphism in patients with HSP. The purpose of this study is to examine the relationship between IL-1beta gene polymorphism and renal involvement in HSP. METHODS: Patients from mideast Korea with HSP were studied. All patients had at least 6 months of follow up. Patients and ethnically matched controls were genotyped for IL-1beta gene polymorphism by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: Thirty-four patients(all younger than 15 years old) who had been diagnosed with HSP and 27 controls were examined. No allele or genotype differences between the HSP and control groups were observed. No significant association between the carriage of IL-1beta(-511) T allele and renal involvement(P=0.525, OR:1.417, CI:0.545-3.686) was found. CONCLUSION: In unselected patients with HSP, carriage of IL-1beta(-511) T allele does not appear to influence renal involvement.

F508 amino acid deletion mutation of CFTR gene in Korean lung cancer patients

Mutations of the transmembrane conductance regulator (CFTR) gene in cystic fibrosis lead to dysfunction of the lung, pancreas, and sweat glands, etc. To investigate the possibility of the relationship between lung cancer and the mutations of CFTR gene, we determined amino acid sequences using reverse transcription-polymerase chain reaction (RT-PCR) and DNA sequencing. In this study, the deletion mutation of 508th amino acid in one of nine lung caner patients was found confirming that CFTR gene mutation exists in a Korean lung cancer patient.

Mutation of Ha-ras Oncogene in Rat Salivary Gland Tumors Induced by DMBA / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The incidence of salivary gland tumor is approximately 2% among all head and neck tumors, of which malignant cases account for only about 5%. Much research has been performed in order to clarify the mechanism of oncogene activation, however salivary gland tumors remain understudied. We performed this study in order to characterize the ras gene in these tumors. MATERIALS AND METHODS: We treated white rats with 7, 12-dimethylbenz[a]anthracene (DMBA) and confirmed the occurrence of salivary gland tumors after ten to thirty weeks. Isolated genomic DNAs from tumor tissues were added to NIH 3T3 cells. In order to detect Ha-ras mutations, we performed a two-step PCR-RFLP and 7analyzed the mutated sequences. RESULTS: We induced salivary gland tumors by DMBA treatment in white rats. Isolated DNAs from the tumor tissues transformed the NIH 3T3 cells. Point mutations were observed in codons 12 and 61 of the Ha-ras oncogene. The total frequency of point mutations was 13.9% in DMBA-induced salivary gland tumors in rats. CONCLUSION: Our results demonstrate that a variety of cancers ras oncogene mutations were also found in salivary gland tumors. We confirmed that a point mutation of the Ha-ras oncogene in a DMBA-induced salivary gland tumor occurs at a frequency of 13.9%.