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1.
Int J Pediatr Otorhinolaryngol ; 159: 111210, 2022 Aug.
Article in English | MEDLINE | ID: mdl-35724491

ABSTRACT

OBJECTIVE: The purpose of this study was to evaluate the functional duration and survival rate of tympanostomy ventilation tubes and the complications associated with their use in pediatric patients who underwent tube insertion for otitis media with effusion (OME). Complications were analyzed including recurrence and tympanic membrane perforation after the tube removal or extrusion. METHODS: Altogether, 447 ears from 234 pediatric patients younger than 15 years of age were studied retrospectively. All patients had undergone long-term tympanostomy ventilation tube: the Goode T-tube insertion for OME at the Osaka Women's and Children's Hospital, which is the pediatrics specialty hospital between April 2014 and March 2016. They were typically followed up every 3-4 months or more frequently if necessary due to otorrhea or tube infection. Subsequently, the tube duration, survival rates of the tube especially at 22 months after insertion defined as "full-term placement", and the rates of recurrence and perforation were calculated and statistically evaluated. RESULTS: Of 447 ears, 335 ears from 184 patients underwent their first tube insertion, and 112 ears from 64 patients underwent their second or subsequent tube insertion within the targeted period. Two hundred ears from 106 patients were associated with a cleft palate. The survival rate at full-term placement was 51.7%. The recurrence rate was 56.3%, and the rate of the tympanic perforation was 8.5%. CONCLUSIONS: Approximately half of the tubes survived for 22 months. The perforation rate was relatively low; however, recurrence of OME was seen in more than half the ears.


Subject(s)
Otitis Media with Effusion , Pediatrics , Tympanic Membrane Perforation , Child , Female , Humans , Kaplan-Meier Estimate , Middle Ear Ventilation/adverse effects , Otitis Media with Effusion/complications , Retrospective Studies , Tissue Adhesions/etiology , Treatment Outcome , Tympanic Membrane Perforation/etiology
2.
J Atheroscler Thromb ; 23(11): 1276-1285, 2016 Nov 01.
Article in English | MEDLINE | ID: mdl-27301461

ABSTRACT

AIM: Sterol regulatory element-binding protein (SREBP)-1c is the dominant liver insulin-stimulated isoform and strongly correlates with diabetic dyslipidemia characterized by hyperinsulinemia [i.e., high-density lipoprotein cholesterol (HDL-C) levels and hypertriglyceridemia]. MicroRNA (miRNA) 33b is harbored in the intron of SREBP-1c and represses ATP-binding cassette, sub-family A, and member 1 (ABCA1) expression, essential for HDL formation. We measured plasma miRNA33b levels as possible biomarkers for diabetic dyslipidemia in patients with type 2 diabetes mellitus (T2DM) showing insulin resistance. METHODS: The participants included 50 patients with T2DM (M/F 31/19) enrolled in an educational program for controlling blood glucose levels at Hirosaki University Hospital. HbA1c, fasting plasma glucose, insulin, and lipid levels were determined. Plasma miRNA33b, miRNA33a and miRNA148a were quantified using a TaqMan® MicroRNA Assay, and values were corrected with reference to miRNA16. RESULTS: Mean BMI of participants were 28.2±6.6 (kg/m2) and the Homeostasis Model Assessment of Insulin Resistance was 4.3±2.7. Patients' laboratory findings indicated diabetic dyslipidemia with insulin resistance. Plasma miRNA33b/16 levels revealed a positive correlation with plasma insulin level (r=0.326, P=0.021), serum C-peptide (r=0.280, P=0.049), and triglyceride (r=0.351, P=0.012), but no association with HDL-C (r=-0.210, P=0.143). The blood level of miRNA33a was approximately 1/150th of that of miRNA33b and was not correlated with the above parameters. CONCLUSION: We postulated that plasma miRNA33b may be useful as a new metabolic biomarker of dyslipidemia in patients with T2DM as well as metabolic syndrome via an insulin/SREBP-1c/miRNA33b/ABCA1 pathway.


Subject(s)
Biomarkers/blood , Diabetes Mellitus, Type 2/blood , Dyslipidemias/blood , Insulin Resistance , MicroRNAs/blood , Blood Glucose/metabolism , Female , Follow-Up Studies , Glycated Hemoglobin/metabolism , Humans , Insulin/blood , Lipids/analysis , Male , Metabolic Syndrome/blood , Middle Aged , Prognosis , Risk Factors
3.
Intern Med ; 55(7): 765-8, 2016.
Article in English | MEDLINE | ID: mdl-27041161

ABSTRACT

Adrenal insufficiency may occur in patients with liver cirrhosis. The assessment of hypothalamus-pituitary-adrenal function is important in such patients, but there is no consensus as to how it should be performed. We herein report the results of our evaluation of the adrenal function in two patients with hypocortisolism accompanied by liver cirrhosis. The patients lacked the typical features of hypocortisolism. One was diagnosed with hypocortisolism accompanied by liver cirrhosis while the other had secondary adrenal insufficiency caused by a hypothalamic disorder. Hypocortisolism accompanied by liver cirrhosis should be evaluated by endocrine tests to determine its pathogenesis. A low-dose adrenocorticotropic hormone test may be appropriate for non-critically ill cirrhotic patients.


Subject(s)
Adrenal Insufficiency/blood , Adrenocorticotropic Hormone/blood , Hydrocortisone/blood , Liver Cirrhosis/blood , Pituitary-Adrenal System/physiopathology , Adrenal Insufficiency/complications , Adrenal Insufficiency/physiopathology , Female , Humans , Liver Cirrhosis/complications , Liver Cirrhosis/physiopathology , Male , Middle Aged
4.
Diabetes Res Clin Pract ; 99(1): 30-8, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23137417

ABSTRACT

AIMS: Cholesterol efflux with high-density lipoprotein (HDL) particles has an important role in the first step of reverse cholesterol transport (RCT). However, HDL function in type 2 diabetes has not been well investigated thoroughly. We measured cholesterol efflux in 36 patients with type 2 diabetes compared with 9 controls without diabetes. METHODS: The HDL fraction was separated with polyacrylamide gel and recovered using the protein recovery system. Concentration adjusted HDL fraction was used to determine HDL-mediated cholesterol efflux (Efflux-hdl) from THP-1 derived macrophages. We measured paraoxonase-1 (PON 1) activity to determine antioxidation capacity, serum amyloid A protein (SAA) to determine inflammatory response, and carboxymethyl-lysin (CML) to determine antiglucoxidative capacity. RESULTS: Efflux-hdl demonstrated no correlation with plasma apoprotein A-1 (ApoA-I) or HDL-cholesterol in patients with diabetes. PON1 activity in the patients' HDL fraction was positively correlated with Efflux-hdl (r=0.39, p=0.02), and showed a negative tendency with HbA1c levels (r=-0.28, p=0.10). SAA and CML levels did not demonstrate correlation with Efflux-hdl in patients with diabetes. CONCLUSION: We confirmed the functional changes in HDL particles in the patients. Efflux-hdl from macrophages was reduced depending upon the decrease in PON1 activity, which was inversely related to HbA1c levels.


Subject(s)
Aryldialkylphosphatase/blood , Diabetes Mellitus, Type 2/metabolism , Lipoproteins, HDL/blood , Aged , Apolipoprotein A-I/blood , Apolipoprotein A-I/metabolism , Atherosclerosis/etiology , Atherosclerosis/metabolism , Biological Transport , Biomarkers/blood , Biomarkers/metabolism , Cell Line , Cholesterol/blood , Cholesterol/metabolism , Cholesterol, HDL/blood , Cholesterol, HDL/metabolism , Diabetes Mellitus, Type 2/immunology , Diabetes Mellitus, Type 2/physiopathology , Female , Glycated Hemoglobin/analysis , Humans , Hyperglycemia/etiology , Hyperglycemia/metabolism , Lipoproteins, HDL/isolation & purification , Lipoproteins, HDL/metabolism , Lysine/analogs & derivatives , Lysine/blood , Lysine/metabolism , Macrophages/metabolism , Male , Middle Aged , Serum Amyloid A Protein/analysis , Serum Amyloid A Protein/metabolism
5.
Nihon Jibiinkoka Gakkai Kaiho ; 116(11): 1220-5, 2013 Nov.
Article in Japanese | MEDLINE | ID: mdl-24397120

ABSTRACT

It is hard to cure dacryocystitis caused by a paranasal sinus mucocele with treatment which only targets the mucocele. Also, it is difficult to identify the lacrimal sac and the nasolacrimal duct preoperatively and intraoperatively when the lacrimal passage is markedly changed by the mucocele or previous surgery. We experienced four cases of mucocele complicated by lacrimal stenosis or obstruction. We performed marsupialization of the mucocele and direct silicon intubation or endoscopic dacryocystorhinostomy simultaneously with the use of a fiberoptic illuminator or dacryoendoscopy. Assisted by those devices, lacrimal procedures can now be done quickly and safely regardless of the surgeon's experience. In addition, performing surgeries both for the lacrimal passage and for the mucocele at the same time can minimize the burden on patients.


Subject(s)
Dacryocystorhinostomy , Endoscopy/methods , Mucocele/surgery , Paranasal Sinus Diseases/surgery , Aged , Endoscopy/instrumentation , Female , Humans , Lacrimal Duct Obstruction/complications , Male , Middle Aged , Silicon
6.
J Clin Lipidol ; 6(1): 74-80, 2012.
Article in English | MEDLINE | ID: mdl-22264577

ABSTRACT

BACKGROUND: Type A or B Niemann-Pick disease (NPD) is characterized by the accumulation of sphingomyelin in the lysosomes and cell membranes. This accumulation results because of a mutation in the sphingomyelin phosphodiesterase-1 (SMPD-1) gene that causes a deficit in the acid sphingomyelinase (ASM). OBJECTIVE: Herein, we report on a new point mutation in the SMPD-1 gene that was discovered in a patient with type B NPD. METHODS AND RESULTS: A culture of the patient's fibroblasts demonstrated that the observed clinical symptoms and reduced plasma high-density lipoprotein cholesterol (HDL-C) were associated with a reduced efflux of cholesterol. Examination of the skin fibroblasts demonstrated that ASM activity was reduced to approximately 60% of that observed in control cells, and a newly identified point mutation was found in codon 494 [Gly (GGT) → Cys (TGT)] in the SMPD-1 gene. Furthermore, repeated measurements of the plasma HDL-C levels remained low (17.5-20.5 mg/dL), and the Apo A-I- or HDL-mediated cholesterol efflux from the patient's fibroblasts was significantly reduced as compared with control fibroblasts. CONCLUSION: In summary, we identified a unique point mutation in a patient with type B NPD that was associated with various clinical findings, including a low plasma HDL-C level. This reduced cellular cholesterol efflux may be implicated, at least in part, in low plasma HDL levels.


Subject(s)
Cholesterol, HDL/blood , Cholesterol/metabolism , Niemann-Pick Disease, Type B/genetics , Point Mutation , Sphingomyelin Phosphodiesterase/genetics , Adenocarcinoma/complications , Adenocarcinoma/diagnosis , Adenocarcinoma/surgery , Cells, Cultured , Colonic Neoplasms/complications , Colonic Neoplasms/diagnosis , Colonic Neoplasms/surgery , Cushing Syndrome/complications , Cushing Syndrome/diagnosis , Fibroblasts/metabolism , Genetic Association Studies , Humans , Liver/metabolism , Liver/pathology , Male , Middle Aged , Niemann-Pick Disease, Type B/blood , Niemann-Pick Disease, Type B/complications
7.
Pathol Int ; 60(12): 787-91, 2010 Dec.
Article in English | MEDLINE | ID: mdl-21091838

ABSTRACT

Perineuriomas are uncommon benign peripheral nerve sheath tumors that include soft tissue, sclerosing, reticular, and intraneural variants. Soft tissue perineuriomas arise in a wide anatomic distribution and mostly in patients older than 20 years of age. We report an atypical perineurioma in a 7-year-old girl. The tumor, located in the tongue, was uniformly hypercellular. The tumor cells were spindle-shaped with a slender, elongated, bipolar, wavy cytoplasmic process formation and wavy elongated nuclei, and the architecture was composed of predominantly short fascicles with areas exhibiting a vague storiform pattern. Although the tumor cells generally appeared bland, the tumor showed worrisome features including an infiltrative pattern and occasional mitotic figures. Psammoma bodies were observed in the periphery of the tumor. Immunohistochemically, the cells were positive for epithelial membrane antigen, vimentin, claudin-1, and GLUT-1, but negative for S-100 protein, CD34, and type IV collagen. The authors document a case of soft tissue perineurioma with atypical histological features that occurred in the tongue of a child.


Subject(s)
Nerve Sheath Neoplasms/pathology , Tongue Neoplasms/pathology , Child , Female , Humans , Immunohistochemistry , Nerve Sheath Neoplasms/metabolism , Soft Tissue Neoplasms/metabolism , Soft Tissue Neoplasms/pathology , Tongue Neoplasms/metabolism
8.
J Atheroscler Thromb ; 17(11): 1183-9, 2010 Nov 27.
Article in English | MEDLINE | ID: mdl-20733269

ABSTRACT

AIMS: We studied the effect of insulin on HDL-mediated cholesterol efflux from macrophages. The potential involvement of cholesteryl ester hydrolysis and membrane cholesterol transport was also addressed. METHODS: Human monocyte-derived THP-1 cells were developed into macrophages. Cholesterol efflux was measured by incubating macrophages, labeled with [³H]-cholesterol, with HDL for 24 h. The cells were treated with insulin (0-500 nM) for 30 min prior to the addition of HDL. To investigate the molecular mechanisms of the effect of insulin, the expressions of neutral cholesteryl ester hydrolase (nCEH) and ATP-binding cassette transporter (ABC) G1 were analyzed. RESULTS: Insulin inhibited, in a concentration-dependent manner, HDL-mediated cholesterol efflux from macrophages. Insulin also inhibited the enzyme activity of nCEH and its mRNA and protein expression in cells. Insulin also suppressed the expressions of mRNA and protein for ABCG1. CONCLUSIONS: Insulin inhibits HDL-mediated cholesterol efflux from macrophages, which may result from the suppression of nCEH and ABCG1 expressions. Our findings show part of the potential molecular mechanism of atherogenesis in type 2 diabetes with hyperinsulinemia.


Subject(s)
ATP-Binding Cassette Transporters/metabolism , Cholesterol/metabolism , Insulin/pharmacology , Lipoproteins, HDL/metabolism , Macrophages/drug effects , Macrophages/metabolism , Sterol Esterase/metabolism , ATP Binding Cassette Transporter 1 , ATP Binding Cassette Transporter, Subfamily G, Member 1 , ATP-Binding Cassette Transporters/genetics , Blotting, Western , Cells, Cultured , Humans , Hypoglycemic Agents/pharmacology , RNA, Messenger/genetics , Reverse Transcriptase Polymerase Chain Reaction , Serine Proteases , Sterol Esterase/genetics
9.
Gan To Kagaku Ryoho ; 37(8): 1617-21, 2010 Aug.
Article in Japanese | MEDLINE | ID: mdl-20716901

ABSTRACT

Because the expert nurse of the chemotherapy center collected his profile from his chart and the hospital summary of nursing and we orientated about the induced chemotherapy regimen to the patient who got it after discharge from the ward former, we could not grasp neither his general condition nor mental status adequately. The merit of the outpatient chemotherapy is the improvement of the quality of life, but the patient feels the solitude and anxiety because of the lack of the medical and nursing staff around him. Then we changed that we have visited the patients to collect their profile and orientate about new regimen on his bedside for the smooth conversion to the outpatient chemotherapy. We visited a-total of 45 patients in 2007. Thirty-eight patients visited before their discharge answered, The orientation of the new chemotherapy before my discharge let me get with a security. The visit also enabled both staffs of the chemotherapy center and the ward to possess the common information of each patient and to do the common nursing. We thought that the visit before discharge was effective for the smooth conversion to the outpatient chemotherapy. We would like to reduce the anxiety of the patients who had chemotherapy and to support their struggle against diseases, cooperating to other department and standardizing our care program.


Subject(s)
Ambulatory Care , Communication , Neoplasms/drug therapy , Patient Care Team , Adult , Aged , Female , Humans , Male , Middle Aged
11.
Endocr J ; 57(3): 267-72, 2010.
Article in English | MEDLINE | ID: mdl-20086312

ABSTRACT

Cushing's syndrome, including its mild form/state of adrenal-dependent subset (subclinical Cushing's syndrome; subCS), is known to enhance glucose intolerance, hypertension and obesity. Recently, subclinical Cushing's disease (subCD) has been identified, but its prevalence and the extent of consequent metabolic derangement are unclear. We screened 90 type 2 diabetic patients hospitalized in our department for subCD, according to the diagnostic guideline proposed by the working group of Japanese Ministry of Health, Welfare and Labor in 2006. Plasma ACTH and cortisol levels in the morning and at midnight were determined, and overnight 0.5 mg dexamethasone suppression test (DST) was performed. Those who showed poor cortisol suppression in DST underwent the desmopressin (DDAVP) test. Fifty-seven patients (63.3%) demonstrated abnormally high midnight cortisol levels (>or=2.5 microg/dL), while only nine of them failed to suppress plasma cortisol levels to <3 microg/dL after DST. Although none of the eight patients who underwent the DDAVP test demonstrated the anticipated paradoxical rise in plasma ACTH, these eight patients (8.9%) endocrinologically met the screening criteria of subCD. Since a considerable percentage of pituitary adenomas causing overt Cushing's disease are not identifiable in magnetic resonance imaging, many of those causing subCD may also be unidentifiable. Further follow-up studies including confirmatory testing and pituitary imaging are necessary.


Subject(s)
Adrenocorticotropic Hormone/blood , Diabetes Mellitus, Type 2/diagnosis , Hydrocortisone/blood , Adult , Aged , Circadian Rhythm , Cushing Syndrome/diagnosis , Diabetes Mellitus, Type 2/epidemiology , Female , Humans , Male , Middle Aged , Pituitary ACTH Hypersecretion/diagnosis , Pituitary ACTH Hypersecretion/epidemiology
12.
Atherosclerosis ; 206(2): 434-8, 2009 Oct.
Article in English | MEDLINE | ID: mdl-19376519

ABSTRACT

High-density lipoprotein (HDL) mediates cholesterol efflux, which is the initial and rate-limiting step of reverse cholesterol transport. The present study was undertaken to evaluate the effect, on macrophage cholesterol efflux, of functional modification of HDL by its glycation. We also investigated the effects of the glycation-inhibitors metformin (MF) and aminoguanidine (AG) on glycated HDL-mediated cholesterol efflux. Human plasma HDL (5mg protein/mL) was glycated by incubation with 3-deoxyglucosone (3-DG). Glycation was monitored by measuring carboxymethyl-lysine (CML). HDL-mediated cholesterol efflux was determined using human THP-1-derived macrophages pre-labeled with [(3)H]-cholesterol. To measure expression of potential factors related to the efflux in the macrophages, ATP-binding cassette transporter (ABC) G1 was analyzed by real-time quantitative RT-PCR and Western blot. Glycation of HDL significantly reduced the HDL-mediated cholesterol efflux from THP-1-derived macrophages (87.7+/-4.2% of control, n=9, p<0.0001). In the presence of metformin or aminoguanidine (100mM), glycated HDL-mediated cholesterol efflux was restored to 97.5+/-4.3% and 96.9+/-3.1%, respectively. Exogenous HDL reduced ABCG1 mRNA and protein expression in THP-1-derived macrophages, but glycation deprived HDL of this effect. We conclude that glycated HDL particles are ineffective as acceptors of ABCG1-mediated cholesterol efflux; and this may explain, at least in part, accelerated atherosclerosis in diabetic patients. Metformin serves as a possible candidate to restore impaired cholesterol efflux and reverse cholesterol transport.


Subject(s)
Cholesterol/metabolism , Lipoproteins, HDL/physiology , Macrophages/metabolism , Metformin/pharmacology , ATP Binding Cassette Transporter, Subfamily G, Member 1 , ATP-Binding Cassette Transporters/metabolism , Cells, Cultured , Deoxyglucose/analogs & derivatives , Deoxyglucose/metabolism , Gene Expression/drug effects , Glycation End Products, Advanced/antagonists & inhibitors , Glycosylation , Guanidines/pharmacology , Humans , Lipoproteins, HDL/chemistry
13.
Am J Med Sci ; 335(5): 398-402, 2008 May.
Article in English | MEDLINE | ID: mdl-18480660

ABSTRACT

A 38-year-old woman with RET gene mutation presented with tumors in her thyroid and bilateral adrenal glands. I-metaiodobenzylguanidine scintigraphy revealed accumulation of the radioisotope in both adrenal glands. Both plasma adrenaline and noradrenaline levels were elevated. The circadian rhythms for plasma adrenocorticotropic hormone (ACTH) and cortisol levels were disturbed. Plasma ACTH and cortisol levels failed to be suppressed by an overnight dexamethasone test, suggesting autonomic secretion of ACTH and cortisol, although the patient had no typical Cushingoid features, hypertension, or impaired glucose tolerance. Pathological examination showed that these tumors were pheochromocytoma and thyroid medullary carcinoma, respectively, both of which highly expressed corticotropin-releasing factor, urocortin1, and urocortin3. Together with the endocrinological and pathological observations, the patient was diagnosed as multiple endocrine neoplasia type II with corticotropin-releasing factor- and urocortin-producing tumors that stimulated ACTH and glucocorticoid secretion.


Subject(s)
Adrenal Gland Neoplasms/chemistry , Carcinoma, Medullary/chemistry , Corticotropin-Releasing Hormone/analysis , Multiple Endocrine Neoplasia Type 2a/chemistry , Pheochromocytoma/chemistry , Thyroid Neoplasms/chemistry , Urocortins/analysis , Adrenocorticotropic Hormone/blood , Adult , Female , Humans , Hydrocortisone/blood , Immunohistochemistry , Multiple Endocrine Neoplasia Type 2a/complications , Multiple Endocrine Neoplasia Type 2a/pathology
14.
J Atheroscler Thromb ; 15(1): 20-5, 2008 Feb.
Article in English | MEDLINE | ID: mdl-18270459

ABSTRACT

AIM: ApoA-I and HDL promote cellular cholesterol efflux in the early stages of the reverse cholesterol transport (RCT) pathway. A low plasma HDL-C level is characteristic of atherogenic dyslipidemia in patients with type 2 diabetes. We evaluated plasma lipid levels and the expression of factors related to RCT in type 2 diabetic patients, and the effects of an HMG-CoA reductase inhibitor, simvastatin, were studied. METHODS: Messenger RNA (mRNA) expression in circulating mononuclear cells was analyzed by reverse transcription-polymerase chain reaction (RT-PCR), focusing on the following factors: liver X receptor alpha (LXR alpha), ATP-binding cassette A1 (ABCA1), scavenger receptor class B type 1 (SR-B1), apolipoprotein E (ApoE), apolipoprotein A-1 (ApoA-1), caveolin, and cholesterol ester transfer protein (CETP). Type 2 diabetic subjects (n=29) were divided into three subgroups: patients with normolipidemia (DM group, n=11), patients with untreated hyperlipidemia (DMHL group, n=10), and those with hyperlipidemia treated with simvastatin 5-10mg/day (DMST group, n=8). The control group (CNT group) included seven healthy volunteers. RESULTS: Simvastatin treatment significantly increased plasma levels of ApoA-I compared to the other three groups. Simvastatin treatment improved the expression of mRNA for LXRalpha, ABCA1, and ApoA-I compared with DMHL or control groups. CONCLUSION: Our data suggest that RCT may be reduced in type 2 diabetic patients with hyperlipidemia, and simvastatin may be able to improve reverse cholesterol transport for this population of diabetic patients.


Subject(s)
Cholesterol, HDL/blood , Cholesterol/blood , Diabetes Mellitus, Type 2/blood , Hyperlipidemias/drug therapy , Simvastatin/pharmacology , Aged , Apolipoprotein A-I/blood , Female , Gene Expression , Humans , Hydroxymethylglutaryl-CoA Reductase Inhibitors , Male , Middle Aged
15.
Am J Dent ; 18(5): 327-30, 2005 Oct.
Article in English | MEDLINE | ID: mdl-16335041

ABSTRACT

PURPOSE: To evaluate the shear bond strength of two dual-cured resin luting cements (Linkmax HV and Panavia Fluoro Cement) to machinable glass-ceramics (Decsy Machinable Ceramic) and the effect of three silane coupling agents (Clearfil Porcelain Activator, Ceramic Primer, and Porcelain Liner M) on the bond strength. METHODS: Disk-shaped specimens fabricated from machinable glass-ceramic blocks using a low-speed cutting saw were either treated or not treated with one of three silane coupling agents and then bonded together with one of two dual-cured resin luting cements. Specimens were stored in water at 37degrees C for 24 hours and/or thermal cycled 50,000 times before shear bond strength testing. RESULTS: Regardless of the resin luting cement and thermal cycling, specimens treated with the Clearfil Porcelain Activator showed the highest shear bond strength among all the treatments. Surface treatment of the Clearfil Porcelain Activator showed significantly greater shear bond strength after 50,000 thermocycles compared with other treatments. However, significant differences in bond strength were observed between 0 and 50,000 thermocycles for all treatments.


Subject(s)
Ceramics/chemistry , Composite Resins/chemistry , Dental Cements/chemistry , Resin Cements/chemistry , Silanes/chemistry , Analysis of Variance , Shear Strength
16.
Am J Dent ; 17(4): 249-52, 2004 Aug.
Article in English | MEDLINE | ID: mdl-15478485

ABSTRACT

PURPOSE: To evaluate the shear bond strengths of two dual-cured resin luting cements to pure zirconium and the effect of zirconate coupling agent on the bond strength. METHODS: The two different-shaped pure zirconium specimens (99.9%) were untreated or treated with one of the four primers including zirconate coupler and then cemented together with one of the two dual-cured resin luting cements. Half of the specimens were stored in water at 37 degrees C for 24 hours and the other half thermocycled 20,000 times before shear bond strength testing. RESULTS: Regardless of the resin luting cement and thermocycling, specimens treated with the mixture of zirconate coupler and resin bonding agent showed the highest shear bond strength among the five treatments. Surface treatment with the mixture of zirconate coupler and resin bonding agent showed significantly greater shear bond strength compared with other treatments at 20,000 thermocycles. The application by the mixture of zirconate coupler and resin bonding agent on the pure zirconium metal surface appears to be effective for bonding between zirconium and dual-cured resin luting cements.


Subject(s)
Dental Bonding , Dental Materials/chemistry , Resin Cements/chemistry , Zirconium/chemistry , Aluminum Silicates/chemistry , Analysis of Variance , Humans , Materials Testing , Methacrylates/chemistry , Shear Strength , Silanes/chemistry , Surface Properties , Thermodynamics , Water/chemistry
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