Correlation between microhardness and wear resistance of dental alloys against monolithic zirconia

Purpose@#The aim of this study is to compare the hardness according to the conditions of metal alloys. Moreover, the correlation between the cast crown hardness before and after wear testing and the degree of wear for each dental alloy was assessed. @*Materials and Methods@#Cast crowns of three metal alloys (Co-Cr, gold, and Ni-Cr alloys) opposing smooth-surface monolithic zirconia were used. The Vickers microhardness of the ingot (which did not undergo wear testing) and the cast crown before and after wear testing were measured for each alloy. Two-way ANOVA and Scheffé tests were used to compare the measured hardness values. Moreover, the Pearson correlation coefficient was used to evaluate the relationship between the surface hardness and the wear of the cast crown (α=.05). @*Results@#There was no significant difference in the hardness before and after wear testing for the gold alloy (P >.05); however, the hardness of the worn surface of the cast crown increased compared to that of the cast crown before the wear tests of Ni-Cr and Co-Cr alloys (P .05). @*Conclusion@#There was a significant difference in hardness between dental alloys under the same conditions. No correlation existed between the surface hardness of the cast crown before and after wear testing and the wear of the cast crown.

Correlation between microhardness and wear resistance of dental alloys against monolithic zirconia

Purpose@#The aim of this study is to compare the hardness according to the conditions of metal alloys. Moreover, the correlation between the cast crown hardness before and after wear testing and the degree of wear for each dental alloy was assessed. @*Materials and Methods@#Cast crowns of three metal alloys (Co-Cr, gold, and Ni-Cr alloys) opposing smooth-surface monolithic zirconia were used. The Vickers microhardness of the ingot (which did not undergo wear testing) and the cast crown before and after wear testing were measured for each alloy. Two-way ANOVA and Scheffé tests were used to compare the measured hardness values. Moreover, the Pearson correlation coefficient was used to evaluate the relationship between the surface hardness and the wear of the cast crown (α=.05). @*Results@#There was no significant difference in the hardness before and after wear testing for the gold alloy (P >.05); however, the hardness of the worn surface of the cast crown increased compared to that of the cast crown before the wear tests of Ni-Cr and Co-Cr alloys (P .05). @*Conclusion@#There was a significant difference in hardness between dental alloys under the same conditions. No correlation existed between the surface hardness of the cast crown before and after wear testing and the wear of the cast crown.

Joint stability of internal conical connection abutments with or without hexagon indexes: an in vitro study

Purpose@#The purpose of this study was to compare the axial displacement of the hexagonal and conical abutment in internal conical connection implant after screw tightening and cyclic loading. @*Materials and Methods@#Internal conical connection implants were divided into two groups (n = 10): group HEX, hexagonal abutment; and group CON, conical 2-piece abutments. The axial displacement and removal torque values were measured after 30 Ncm torque tightening and 250N loading test of 100,000 cycles. The Student t test with 5% significance level was used to evaluate the data. @*Results@#HEX group demonstrated significantly higher axial displacement values after 30 Ncm tightening in comparison to the CON group (P < 0.05). No significant difference was found in axial displacement after cyclic loading (P = 0.052). Removal torque loss before and after the cyclic loading both revealed no significant difference between groups (P = 0.057 and P = 0.138). Removal torque value decreased after cyclic loading in both groups (P < 0.05). @*Conclusion@#Overall, both abutment with or without hexagon index presented similar biomechanical performance except HEX group demonstrated significantly more axial displacement after applying tightening torque.

Iatrogenic subcutaneous cervicofacial emphysema with pneumomediastinum after class V restoration

Subcutaneous facial emphysema after dental treatment is an uncommon complication caused by the invasion of high-pressure air; in severe cases, it can spread to the neck, mediastinum, and thorax, resulting in cervical emphysema, pneumomediastinum, and pneumothorax. The present case showed subcutaneous cervicofacial emphysema with pneumomediastinum after class V restoration. The patient was fully recovered after eight days of conservative treatment. The cause of this case was the penetration of high-pressure air through the gingival sulcus, which had a weakened gingival attachment. This case indicated that dentists should be careful to prevent subcutaneous emphysema during common dental treatments using a high-speed hand piece and gingival retraction cord.

Development of Educational Material for Blood Donor Interview through the Cognitive Evaluation of Donor History Questionnaires / 대한수혈학회지

BACKGROUND: Screening for healthy blood donors through donor interviews is essential to the safety of donors and blood resources. Our goal was to suggest educational material for donor interviewers and donors, as well as supplemental material for interview sites, which will help provide an effective interview process. METHODS: We conducted surveys regarding experiences in donor interviews from donor interviewers and cognitive interviews about difficulties during interview from blood donors between September and October of 2015. We additionally conducted a post-survey about provided educational and supplemental materials between December 2015 and January 2016. RESULTS: The possibility of an incorrect answer in the donor history questionnaire (DHQ) was high for questions about sexual contact, imprisonment, or medication, and the reasons were incorrect memories, ignorance about donor interview, or protection of privacy. Cognitive interviews of donors revealed questions and terminology that are difficult to understand. Donor interviewers could obtain improved understanding of the DHQ through educational materials, which were found to be useful for new interviewers or donors. Use of a supplemental flip book for the interview process was found to be useful, especially for blood centers with small blood donations. CONCLUSION: This study investigated difficulties in the donor interview from the perspective of donor interviewers and donors and suggested educational and supplemental materials to address these difficulties. These materials will induce correct and honest answers from blood donors through education and guidance about the donor interview process and help secure the safety of blood products.

Metal stain on monolithic zirconia restoration: A case report

In restorative treatment using fixed dental prostheses, dentists should select appropriate restoration material among various types of dental materials. The strength, marginal fit, esthetics, wear resistance, biocompatibility, and cost are important factors in the choice of restoration materials. The present case showed a surface stain on a monolithic zirconia restoration that was due to wear between the monolithic zirconia restoration and the base metal alloy restoration. This phenomenon was confirmed by surface roughness measurement and electron probe micro-analysis.

Evaluation of bone formation and membrane degradation in guided bone regeneration using a 4-hexylresorcinol-incorporated silk fabric membrane / 대한악안면성형재건외과학회지

BACKGROUND: The aims of present study were (1) to evaluate new bone formation among the 4-hexylresorcinol (4HR)-incorporated silk fabric membrane (SFM), conventional SFM, and uncovered control groups and (2) to compare the amount of residual membrane between the 4HR-incorporated SFM and conventional SFM in a rabbit parietal defect model. METHODS: Nine New Zealand white rabbits were used for this animal study. After the formation of a bilateral parietal bone defect (diameter 8.0 mm), either 4HR-incorporated SFM or conventional SFM was grafted into the defect. The defect in the control was left uncovered. New bone formation and the amount of residual membrane were evaluated by histomorphometry at 8 weeks after the operation. RESULTS: The total amount of new bone was 37.84 +/- 8.30 % in the control, 56.64 +/- 15.74 % in the 4HR-incorporated SFM group, and 53.35 +/- 10.52 % in the conventional SFM group 8 weeks after the operation. The differences were significant between the control and 4HR-incorporated SFM group (P = 0.016) and between the control and conventional SFM group (P = 0.040). The residual membrane was 75.08 +/- 10.52 % in the 4HR-incorporated SFM group and 92.23 +/- 5.46 % in the conventional SFM group 8 weeks after the operation. The difference was significant (P = 0.039). CONCLUSIONS: The 4HR-incorporated SFM and conventional SFM groups showed more bone regeneration than the control group. The incorporated 4HR accelerated the partial degradation of the silk fabric membrane in a rabbit parietal defect model 8 weeks after the operation.

Relationship Between Indoor Air Pollutant Levels and Residential Environment in Children With Atopic Dermatitis

PURPOSE: This study was aimed to investigate the relationship between indoor air pollutant levels and residential environment in children with atopic dermatitis (AD) living in Seoul. METHODS: A total of 150 children with AD were included. Residential environment was assessed by questionnaires which were completed by their parents. To evaluate the level of exposure to the indoor air pollutants, concentrations of the indoor air pollutants including particulate matter with diameter less than 10 microm (PM10), formaldehyde, carbon dioxide (CO2), carbon monoxide (CO), nitrogen dioxide (NO2), Total Volatile Organic Compound (TVOC), benzene, toluene, ethyl-benzene, xylene, styrene, bacterial aerosols, and airborne fungi were measured. RESULTS: A significant difference was exhibited in the levels of PM10 in case of visible fungus on the walls (P=0.047). There was relationship between the construction year of the house, moving to a newly constructed building within 1 year and formaldehyde level. With the use of artificial air freshener, the differences were found in the concentrations of TVOC (P=0.003), benzene (P=0.015), toluene (P=0.012) and ethyl-benzene (P=0.027). The concentration of xylene was significantly high when oil was used as heating fuel (P=0.015). Styrene exhibited differences depending on building type and its concentrations were significantly high in a residential and commercial complex building (P=0.005). The indoor concentration of bacterial aerosols was significantly low with the use of air cleaner (P=0.045). High NO2, benzene concentrations were present in case of almost no ventilation (P=0.028 and P=0.028, respectively). CONCLUSIONS: Individual residential environments are closely related with the levels of the indoor air pollutants. To alleviate AD symptoms, simple questions about residential environments such as visible fungus on the walls and the use of artificial air freshener are helpful to assess the possibility of increased indoor air pollutant levels when direct measurement is not available.

Horizontal Ridge Augmentation with Piezoelectric Hinge-Assisted Ridge Split Technique in the Atrophic Posterior Mandible / 대한악안면성형재건외과학회지

Onlay bone grafting, guided bone regeneration, and alveolar ridge split technique are considered reliable bone augmentation methods on the horizontally atrophic alveolar ridge. Among these techniques, alveolar ridge split procedures are technique-sensitive and difficult to perform in the posterior mandible. This case report describes successful implant placement with the use of piezoelectric hinge-assisted ridge split technique in an atrophic posterior mandible.

Evaluation of Point-of-Care Testing Devices for Pre-donation Alanine Aminotransferase Test / 대한수혈학회지

BACKGROUND: In Korea, since 1990, in an effort to reduce the transmission of non-A, non-B hepatitis, all blood donations with alanine aminotransferase (ALT) levels above 65 IU/L are discarded. In 2012, 64.8% of the disposed blood units at the Korean Red Cross blood centers were due to high ALT levels. Pre-donation ALT testing might prevent unnecessary blood donation and save related expenses. We evaluated performance of point-of-care test (POCT) devices for pre-donation ALT screening. METHODS: ALT levels by four ALT POCT devices (Mission C100, Acon; Reflotron Plus, Roche; Labgeo PT10, Samsung; and FDC NX500, Fujifilm) were compared with venous blood results using laboratory chemistry analyzers (AU series, Beckman Coulter Inc.). Intraclass correlation coefficients (ICCs), sensitivity (ability to detect ALT > or =65 IU/L), and specificity (ability to detect <65 IU/L) for each method were calculated. RESULTS: Compared with the laboratory analyzers, the ICCs of ALT measurements by Mission C-100, Reflotron Plus, Labgeo PT10, and FDC NX500 were 0.96 (95% confidence interval (CI): 0.95~0.97), 0.99 (95% CI: 0.99~0.99), 0.98 (95% CI: 0.98~0.98), and 0.94 (95% CI: 0.91~0.96), respectively. The sensitivity was 80.95% for Mission C-100, 83.33% for Reflotron Plus, 78.57% for Labgeo PT10, and 97.62% for FDC NX500. The specificity was 99.13% for Mission C-100, 100.00% for Reflotron Plus, 99.78% for Labgeo PT10, and 98.26% for FDC NX500. CONCLUSION: The ALT POCT devices showed almost perfect agreement with the laboratory analyzers and could be useful for pre-donation ALT screening. However, before implementing ALT POCT devices, cost-effectiveness analyses should be performed.

Membranes for the Guided Bone Regeneration / 대한악안면성형재건외과학회지

Many kinds of membrane have been used for the guided bone regeneration (GBR) technique. However, most membranes do not fulfill all requirements for the ideal membrane for the GBR technique. Among them, collagen membrane has been most widely used. However, its high price and weak tensile strength in wet condition are limitations for wide clinical application. Synthetic polymers have also been used for the GBR technique. Recently, silk based membrane has been considered as a membrane for the GBR technique. Despite many promising preclinical data for use of a silk membrane, clinical data regarding the silk membrane has been limited. However, silk based material has been used clinically as vessel-tie material and an electrospun silk membrane was applied successfully to patients. No adverse effect related to the silk suture has been reported. Considering that silk membrane can be provided to patients at a cheap price, its clinical application should be encouraged.

Correction of Post-traumatic Lower Lip Asymmetry Using Botulinum Toxin Type A

Expression of endoglin and podoplanin in early and advanced oral squamous cell carcinoma

OBJECTIVES: Angiogenesis and lymphangiogenesis are correlated with tumor growth and lymph node metastasis in cases of oral squamous cell carcinoma (OSCC). Endoglin is one of the representative vascular endothelial cell markers. Podoplanin is also a representative marker used in order to detect lymphatic endothelial cells. The aim of this study was to determine the correlation between the expression of endoglin/podoplanin and clinical variables associated with OSCC progression. MATERIALS AND METHODS: Paraffin embedded tissue specimens from 21 patients diagnosed with OSCC were used in this study. Ten patients were diagnosed with early clinical stage (I or II) and 11 patients with advanced clinical stage (III or IV) OSCC. Five patients had positive lymph node involvement. Primary antibodies for endoglin and podoplanin were used to perform the immunohistochemical detection of the vascular and lymphatic endothelial cells. The expression of endoglin and podoplanin was examined by an image analysis program in the three most highly expressed regions of each specimen. RESULTS: The average endoglin expression was observed to be 1.691+/-0.920 in the advanced stage (III, IV) specimens and 0.797+/-0.583 in the early stage (I, II) specimens (P=0.020). The average expression of podoplanin was 0.286+/-0.228 in the advance stage (III, IV) specimens and 0.374+/-0.157 in the early stage (I, II) specimens (P>0.05). There was no statistically significant difference in the expression of endoglin and podoplanin, regardless of whether or not the lymph node was positive. CONCLUSION: The expression of endoglin was significantly higher in the advanced stage specimens than that in the early stage specimens. Therefore, we concluded that endoglin is a useful molecular marker for use in the evaluation of the progression of OSCC.

The Effects of Tetracycline-loaded Silk Fibroin Membrane on Guided Bone Regeneration in a Rabbit Calvarial Defect Model

0.05). Regenerated bone volume (mm3) of 1% TC-loaded SFM, SFM, and control were 36.56+/-8.50, 25.86+/-8.17, and 19.09+/-5.07 at 8 weeks postoperatively, respectively (P<0.05).CONCLUSION: The 1% TC-loaded SFM showed more bone regeneration than the SFM and the uncovered control, in guided bone regeneration.

Pathologic Fractures of the Mandible

The clinical effects of hospitalization in a low pollutant room on atopic dermatitis

BACKGROUND: Environmental pollutants are thought to be one of major triggers of atopic dermatitis (AD). OBJECTIVE: We attempted to evaluate the clinical effects of environment with low indoor pollutant levels on AD management. METHODS: Fifty-one children (mean age 1.7 years) with moderate to severe AD who failed to show improvement with conventional management were recruited. Disease severity was assessed by SCORAD (Scoring of AD) indices. They were admitted in a low pollutant oom for 3-4 days (mean 3.3 days) which was designed to keep low levels of dust, house dust mites, micro-organisms, and indoor air pollutants such as total volatile organic compounds (TVOCs), particulate matter (PM), and so on. Air pollutant levels in the low pollutant room were lower than primary standards defined by the Korean Ministry of Environment. we compared disease severity on admission and after discharge, and the pollutant levels of each patient's home and low pollutant room. RESULTS: The SCORAD was significantly reduced from 42.0 ± 11 .5 to 29.8 ± 8.9 (p < 0.001) by management in a low pollutant room. PM₂.₅, PM₁₀, formaldehyde, TVOCs, carbon dioxide, bacterial suspensions, and indoor molds were significantly higher in the patient's home than low pollutant room. Out of 29 patients who deteriorated after discharge to their home, 8 patients were admitted again, and their SCORAD was rapidly decreased from 53.1 ± 16.2 to 39.2 ± 9.8 (p = 0.036). CONCLUSION: Indoor air pollutants are likely to affect AD in susceptible individuals. Environmental control to lower indoor air pollutant levels might be necessary for better management of AD in some patients.

A Case of Thrombosis of the Inferior Vena Cava and Right Iliac Vein Complicated by Chronic Pancreatitis / 대한소화기내시경학회지

Vascular thrombosis and systemic hypercoagulable states are known complications of pancreatitits. The incidence of vascular obstruction associated with pancreatitis has been reported at 0.9%. They are thought to be secondary to release of proteolytic enzymes of the pancreas and direct vasculitis. Vessels near the head of the pancreas are more frequently involved, and arterial vessels are most commonly affected. Inferior vena cava (IVC) thrombosis however, is a very rare presentation of acute and chronic pancreatitis. Dignosis of IVC thrombosis may be far from easy; the presence of a leg edema, superficial thrombophlebitis or thromboembolic events may arouse clinical suspicion. Therefore, a high degree of suspicion for this complication is necessary in order to render a diagnosis. A case of a 24-year old man with chronic pancreatitis, who was found to have IVC and right iliac vein thrombosis, is herein report with a review of the relevant literature.

A Clinical Analysis on the Pancreaticoduodenectomy / 한국간담췌외과학회지

BACKGROUND/AIMS: During the past several decades pancreaticoduodenectomy has carried a tremendous operative risk. Recently, however, mortality has decreased markedly to around 5%. The aim of this study was to determine the indication, clinical course and complications for the procedure. We also assessed the risk factors of operative morbidity and mortality. METHODS: During the period from June 1979 to July 1998, 155 patients underwent pancreaticoduodenectomy at our institution. The clinical records and pathologic reports were reviewed retrospectively. RESULTS: There were 102 men and 53 women. Mean age was 55.5 years. Indications for the procedure were periampullary carcinoma in 121 patients(78.1%), other malignant tumors in 13 patients(8.2%), and benign diseases including trauma in 21 patients(13.5%). A standard pancreaticoduodenectomy was performed in 113 patients. The remaining 42 patients underwent pylorus preserving pancreaticoduodenectomy. Operative morbidity occurred in 46 patients (29.7%). Pancreatic fistula was the most common complication (11.0%). There were nine operative deaths(5.8%). For the patients with pancreatic fistula, the mortality rate was 41.1%. Patient's age, serum albumin, serum bilirubin, hemoglobin, and leucocyte count had no significant influences on the result of operation. Type of procedure, operation time, amount of transfusion, or use of octreotide were not determining factors for operative mortality. CONCLUSIONS: Pancreaticoduodenectomy was performed in 155 patients with a mortality of 5.8% and a morbidity of 29.7%. The main cause of operative death was pancreatic fistula. There were no specific contributing factors leading to operative morbidity and mortality. It is suggested that technical precision and gentleness are of great importance for patients undergoing pancreaticoduodenectomy

The use of the lumbar hyperextension exercise in the treatment of patients with herniated nucleus pulposus of the lumbar spine

No abstract available.

Diagnostic Endoscopic Sphinteropapillotomy (E.S.T.): An analysis of two cases / 대한소화기내시경학회지

E.S.T. is performed not only for the treatment but also for the diagnosis of biliary tract diseases. E.S.T. serves as a diagnostic aid for some of biliary tract diseases which require such procedures as a peroral cholangioscopy or biopsy of the biliary duct for precise diagnosis and further differential diagnosis. The diseases of our patients were diagnosed by clinical findings and such diagnostic maneuvers as abdominal ultrasonography, intravenous cholangiography, percutaneous transhepatic chorangiography(P.T.C.), endoscopic retrograde chorangiopancreatography(E.R.C.P.), In all the two cases, abdominal ultrasonography revealed dilated extrahepatic duct, but biliary trees were not visualized at E.R.C.P. In one of the two cases, P.T.C. revealed a filling defect with dilated common bile ducts(CBD) but we could not make a differential diagnosis of CBD stone from CBD cancer. In another of the two cases, on which intravenous cholangiography was done, we could not see CBD. For the purpuse of precise diagnosis and further differential diagnosis, we performed EST and then ERCP thraugh widened papillae. With those procedures, CBD stones were shown.