Effect of film thickness of resin cement on bonding efficiency in indirect composite restoration / 대한치과보존학회지

The purpose of this study was to evaluate the effect of film thickness of various resin cements on bonding efficiency in indirect composite restoration by measurement of microtensile bond strength, polymerization shrinkage, flexural strength and modulus, fractographic FE-SEM analysis. Experimental groups were divided according to film thickness ( 0.05). 3. Panavia F showed significantly lower polymerization shrinkage than other resin cements (p < 0.05). 4. Composite-based resin cements showed significantly higher flexural strength and modulus than adhesive-based resin cements (p < 0.05). 5. FE-SEM examination showed uniform adhesive layer and well developed resin tags in composite-based resin cements but unclear adhesive layer and poorly developed resin tags in adhesive-based resin cements. In debonded surface examination, composite-based resin cements showed mixed failures but adhesive-based resin cements showed adhesive failures.

A study on fractural behavior of dentin-resin interface / 대한치과보존학회지

The fracture toughness test is believed as a clinically relevant method for assessing the fracture resistance of the dentinal restoratives. The objectives of this study were to measure the fracture toughness (K1C) and microtensile bond strength of dentin-resin composite interface and compare their relationship for their use in evaluation of the integrity of the dentin-resin bond. A minimum of six short-rod specimens for fracture toughness test and fifteen specimens for microtensile bond strength test was fabricated for each group of materials used. After all specimens storing for 24 hours in distilled water at 37degrees C, they were tensile-loaded with an EZ tester universal testing machin. Statistical analysis was performed using ANOVA and Tukey's test at the 95% confidence level, Pearson's coefficient was used to verify the correlation between the mean of fracture toughness and microtensile bond strength. FE-SEM was employed on fractured surface to describe the crack propagation. Fracture toughness value of Clearfil SE Bond (SE) was the highest, followed by Adper Single Bond 2 (SB), OptiBond Solo (OB), ONE-STEP PLUS (OS), ScotchBond Multi-purpose (SM) and there was significant difference between SE and other 4 groups (p 0.05). Microtensile bond strength of SE was the highest, followed by SB, OB, SM, OS and OS only showed significant lower value (p < 0.05). There was no correlation between fracture toughness and microtensile bond strength values. FE-SEM examination revealed that dentin bonding agent showed different film thickness and different failure pattern according to the film thickness. From the limited results of this study, it was noted that there was statistically no correlation between K1C and microTBS. We can conclude that for obtaining the reliability of bond strength test of dentin bonding agent, we must pay more attention to the test procedure and its profound scrutiny.

A study on fractural behavior of dentin-resin interface / 대한치과보존학회지

The fracture toughness test is believed as a clinically relevant method for assessing the fracture resistance of the dentinal restoratives. The objectives of this study were to measure the fracture toughness (K1C) and microtensile bond strength of dentin-resin composite interface and compare their relationship for their use in evaluation of the integrity of the dentin-resin bond. A minimum of six short-rod specimens for fracture toughness test and fifteen specimens for microtensile bond strength test was fabricated for each group of materials used. After all specimens storing for 24 hours in distilled water at 37degrees C, they were tensile-loaded with an EZ tester universal testing machin. Statistical analysis was performed using ANOVA and Tukey's test at the 95% confidence level, Pearson's coefficient was used to verify the correlation between the mean of fracture toughness and microtensile bond strength. FE-SEM was employed on fractured surface to describe the crack propagation. Fracture toughness value of Clearfil SE Bond (SE) was the highest, followed by Adper Single Bond 2 (SB), OptiBond Solo (OB), ONE-STEP PLUS (OS), ScotchBond Multi-purpose (SM) and there was significant difference between SE and other 4 groups (p 0.05). Microtensile bond strength of SE was the highest, followed by SB, OB, SM, OS and OS only showed significant lower value (p < 0.05). There was no correlation between fracture toughness and microtensile bond strength values. FE-SEM examination revealed that dentin bonding agent showed different film thickness and different failure pattern according to the film thickness. From the limited results of this study, it was noted that there was statistically no correlation between K1C and microTBS. We can conclude that for obtaining the reliability of bond strength test of dentin bonding agent, we must pay more attention to the test procedure and its profound scrutiny.

The effect of thermocycling on the durability of dentin adhesive systems / 대한치과보존학회지

The objectives of this study was to evaluate the effect of thermocycling on the microTBS (microtensile bond strength) to dentin with four different adhesive systems to examine the bonding durability. Freshly extracted 3rd molar teeth were exposed occlusal dentin surfaces, and randomly distributed into 8 adhesive groups: 3-steps total-etching (Scotchbond Multi-Purpose Plus; SM, All Bond-2; AB), 2-steps total-etching (Single Bond; SB, One Step plus; OS), 2-steps self-etching (Clearfil SE Bond; SE, AdheSE; AD) and single-step self-etching systems (Promp L-Pop; PL, Xeno III; XE). Each adhesive system in 8 adhesives groups was applied on prepared dentin surface as an instruction and resin composite (Z250) was placed incrementally and light-cured. The bonded specimens were sectioned with low-speed diamond saw to obtain 1 x 1 mm sticks after 24 hours of storage at 37degrees C distilled water and proceeded thermocycling at the pre-determined cycles of 0, 1,000 and 2,000. The microTBS test was carried out with EZ-tester at 1 mm/min. The results of bond strength test were statistically analyzed using one-way ANOVA/Duncan's test at the alpha < 0.05 confidence level. Also, the fracture mode of debonded surface and the interface were examined under SEM. The results of this study were as follows; 1. 3-step total etching adhesives showed stable, but bond strength of 2-step adhesives were decreased as thermocycling stress. 2. SE showed the highest bond strength, but single step adhesives (PL, XE) had the lowest value both before and after thermocycling. 3. Most of adhesives showed adhesive failure. The total-etching systems were prone to adhesive failure and the single-step systems were mixed failure after thermocycling. Within limited results of this study, the bond strength of adhesive system was material specific and the bonding durability was affected by the bonding step/procedure of adhesive. Simplified bonding procedures do not necessarily imply improved bonding performance.

The effect of thermocycling on the durability of dentin adhesive systems / 대한치과보존학회지

The objectives of this study was to evaluate the effect of thermocycling on the microTBS (microtensile bond strength) to dentin with four different adhesive systems to examine the bonding durability. Freshly extracted 3rd molar teeth were exposed occlusal dentin surfaces, and randomly distributed into 8 adhesive groups: 3-steps total-etching (Scotchbond Multi-Purpose Plus; SM, All Bond-2; AB), 2-steps total-etching (Single Bond; SB, One Step plus; OS), 2-steps self-etching (Clearfil SE Bond; SE, AdheSE; AD) and single-step self-etching systems (Promp L-Pop; PL, Xeno III; XE). Each adhesive system in 8 adhesives groups was applied on prepared dentin surface as an instruction and resin composite (Z250) was placed incrementally and light-cured. The bonded specimens were sectioned with low-speed diamond saw to obtain 1 x 1 mm sticks after 24 hours of storage at 37degrees C distilled water and proceeded thermocycling at the pre-determined cycles of 0, 1,000 and 2,000. The microTBS test was carried out with EZ-tester at 1 mm/min. The results of bond strength test were statistically analyzed using one-way ANOVA/Duncan's test at the alpha < 0.05 confidence level. Also, the fracture mode of debonded surface and the interface were examined under SEM. The results of this study were as follows; 1. 3-step total etching adhesives showed stable, but bond strength of 2-step adhesives were decreased as thermocycling stress. 2. SE showed the highest bond strength, but single step adhesives (PL, XE) had the lowest value both before and after thermocycling. 3. Most of adhesives showed adhesive failure. The total-etching systems were prone to adhesive failure and the single-step systems were mixed failure after thermocycling. Within limited results of this study, the bond strength of adhesive system was material specific and the bonding durability was affected by the bonding step/procedure of adhesive. Simplified bonding procedures do not necessarily imply improved bonding performance.

The effect of cyanate methacrylate on the shear bond strengths to dentin / 대한치과보존학회지

The purpose of this study was to evaluate the effects of cyanate methacylate on the shear bond strengths to bovine dentin surfaces as a dentin primers. Seven experimental adhesives were made with different mass fraction of Isocyanatoetylmethacrylate (IEM), 40wt% HEMA (Wako Pure Chemical Industries Osaka, Japan), 0.6% camphoroquinone, 0.4% amine and ethanol as balance. dentin bonding agents (0, 2, 4, 6, 8, 10, 12%) were made and applied on the surface of bovine dentin specimens of 7 experimental groups. Shear bond strengths were measured using a universal testing machine (Instro 4466). To identify the ratio and modes of cohesive failures, microscopic examinationn was performed. The ultra-structure of resin tags were observed under scanning electron microscope. The results were as follows ; 1) A higher shear bond strengths (33.62 MPa) in group 8% of Cyanate methacrylate to dentin were found, but there were no statistically significancy between Groups (p > 0.05). 2) The higher ratio of cohesive failures mode in group 2, 6, an 10% could be seen than that in any other groups. 3) A shorter resin tags were observed in all experimental groups. This could be resulted that the preventing from the cyanate methacrylate penetrate into dentin owing to reacting it with dentin collagen. Therefore the resin tags were shorter in lengths. Whether the higher bonding strengths of dentin bonding agents can be affected was not been assured with statistic results. The results indicated that the relation between tensile strengths of the dentin adhesives to bovine dentin and resin tags formed into the dentin could not affected. The main reason of increasing the shear bond strength to bovine dentin in experimental groups could not be assured.

The effect of cyanate methacrylate on the shear bond strengths to dentin / 대한치과보존학회지

The purpose of this study was to evaluate the effects of cyanate methacylate on the shear bond strengths to bovine dentin surfaces as a dentin primers. Seven experimental adhesives were made with different mass fraction of Isocyanatoetylmethacrylate (IEM), 40wt% HEMA (Wako Pure Chemical Industries Osaka, Japan), 0.6% camphoroquinone, 0.4% amine and ethanol as balance. dentin bonding agents (0, 2, 4, 6, 8, 10, 12%) were made and applied on the surface of bovine dentin specimens of 7 experimental groups. Shear bond strengths were measured using a universal testing machine (Instro 4466). To identify the ratio and modes of cohesive failures, microscopic examinationn was performed. The ultra-structure of resin tags were observed under scanning electron microscope. The results were as follows ; 1) A higher shear bond strengths (33.62 MPa) in group 8% of Cyanate methacrylate to dentin were found, but there were no statistically significancy between Groups (p > 0.05). 2) The higher ratio of cohesive failures mode in group 2, 6, an 10% could be seen than that in any other groups. 3) A shorter resin tags were observed in all experimental groups. This could be resulted that the preventing from the cyanate methacrylate penetrate into dentin owing to reacting it with dentin collagen. Therefore the resin tags were shorter in lengths. Whether the higher bonding strengths of dentin bonding agents can be affected was not been assured with statistic results. The results indicated that the relation between tensile strengths of the dentin adhesives to bovine dentin and resin tags formed into the dentin could not affected. The main reason of increasing the shear bond strength to bovine dentin in experimental groups could not be assured.

The effect of bonding resin on bond strength of dual-cure resin cements / 대한치과보존학회지

The objective of this study is to evaluate the effect of an additional application of bonding resin on the bond strength of resin luting cements in both the light-cure (LC) and self-cure (SC) modes by means of the microTBS tests. Three combinations of One-Step Plus with Choice, Single Bond with Rely X ARC, and One-Up Bond F with Bistite II were used. D/E resin and Pre-Bond resin were used for the additional application. Twelve experimental groups were made. Three mandibular 3rd molars were used in each group. Indirect composite blocks were cemented on the tooth surface. 1 x 1 mm2 dentin-composite beam for microTBS testing were made and tested. When total-etching dentin adhesives were used, an additional application of the bonding resin increased the bond strength (P 0.05). In conclusion, the results suggest that an additional application of the bonding resin increases bond strength and enhances quality of bonding when using total-etching dentin adhesives.

Effect of the additional application of a resin layer on dentin bonding using single-step adhesives / 대한치과보존학회지

The purpose of this study was to prove that an intermediate resin layer (IRL) can increase the bond strength to dentin by reducing the permeability of single-step adhesives. Flat dentin surfaces were created on buccal and lingual side of freshly extracted third molar using a low-speed diamond saw under copious water flow. Approximately 2.0 mm thick axially sectioned dentin slice was abraded with wet #600 SiC paper. Three single-step self-etch adhesives; Adper Prompt L-Pop (3M ESPE, St Paul, MN, USA), One-Up Bond F (Tokuyama Corp, Tokyo, Japan) and Xeno III (Dentsply, Konstanz, Germany) were used in this study. Each adhesive groups were again subdivided into ten groups by; whether IRL was used or not; whether adhesives were cured with light before application of IRL or not; the mode of composite application. The results of this study were as follows; 1. Bond strength of single-step adhesives increased by an additional coating of intermediate resin layer, and this increasement was statistically signigicant when self-cured composite was used (p < 0.001). 2. When using IRL, there were no difference on bond strengths regardless the curing procedure of single-step adhesives. 3. There were no significant difference on bond strengths between usage of AB2 or SM as an IRL. 4. The thickness of hybrid layer was correlated with the acidity of adhesive used, and the nanoleakage represented by silver deposits and grains was examined within hybrid and adhesive layer in most of single-step adhesives. 5. Neither thickness of hybrid layer nor nanoleakage were related to bond strength.

The efficacy of chemo-mechanical removal of dentin carious lesion / 대한치과보존학회지

Mechanical removals in decayed teeth have been performed using drill and sharp hand instruments. These methods have some disadvantages such as pain, local anesthesia and overextended cavities. Therefore chemo-mechanical excavation of dentin carious lesions has been introduced. The purpose of this study was to evaluate the efficacy of traditional mechanical methods using burs and chemo-mechanical methods (Carisolv) of caries dentin. Mechanical caries removal was carried with low speed round bur. Chemo-mechanical caries excavation was performed with Carisolv (Medi-team), using the Carisolv hand instruments. The mean time to remove caries with two different methods was evaluated and the data analyzed with SPSS software (ver 11.5) by t-test (p 0.05). 4. The remaining carious dentin was detected after the chemo-mechanical removal of the carious dentin, and no smear layer were seen after the mechanical and chemo-mechanical removal of the carious dentin.

The comparison on micro-tensile bond strengths of variable adhesive systems to Class V cavity / 대한치과보존학회지

No abstract available.

Effects of Calcitriol on Delayed Neuronal Damage of Hippocampus in Transient Global Ischemia Model of Mature Gerbil

BACKGROUND: It is well documented that calcium ions perform a major role in neuronal degeneration in cerebrovascular disease and the other degenerative diseases, and that 1,25-dihydroxyvitamin D3 (D3) has the dose-dependent protective effects. This study was performed to examine the effects of different D3 dosages against delayed neuronal damage of the hippocampus. METHODS: Mature mongolian gerbils were injected with either 0.8 microgram/kg/day (group 2) for 5 days or 1.0 microgram/kg/day for 8 days (group 3) prior to the 10 min ligation of the bilateral common carotid arteries. Immunohistochemical expression for the glial cell line-derived neurotrophic factor (GDNF), the basic fibroblast growth factor (bFGF) and the platelet-derived neurotrophic factor (PDNF) was observed in the D3-injected (0.8 microgram/kg/day for 5 days) group. RESULTS: Group 2 showed a highly significant attenuation of delayed neuronal damage in the lateral CA1 region at 7 days after reperfusion. Group 3 showed unilateral or bilateral hemispheric infarcts 24 h after the onset of reperfusion. The D3-injected group showed a markedly increased bFGF expression level. CONCLUSION: The dose-dependent effect of D3 suggests the importance of determining the appropriate D3 dose for clinical applications. Although the mechanism(s) of neuroprotection by D3 remains unclear, D3 may facilitate a reduction in ischemia-induced oxidative stress via the activation of the neurotrophic factors, including bFGF and GDNF.

Spectrophotometric evaluation of sealing effects of several root-end filling materials / 대한치과보존학회지

The purpose of this study is to evaluate the sealing effect of several root-end filling materials using spectrophotometric analysis. 180 single root teeth with one canal were instrumented and canal filled. Root resected and root end preparation was made. Teeth were randomly classified to 5 experimental group(MTA, EBA, IRM, TCP, ZOE) and 1 control group according to root-end filling material MTA group used PRO ROOT MTA, EBA group used Super EBA, TCP group used NEW APATITE LINER TYPE II main component of which is alpha-tricalcium phosphate(TCP). According to manufacture's instruction experimental material was mixed and retrfilled. After 2% methylene blue solution penetration absorbance for each test sample was measured with spectrophotometer (JASCO UV-530, Japan). The mean absorbance of control and experimental group was as follows; MTA : 0.092, IRM : 0.226, Super EBA : 0.255, ZOE : 0.374, Control : 0.425, TCP : 0.501 and the result analyzed by Turkey test at P=0.05 level. Conclusions of this study are as follows; 1. The absorbance increase in follwing sequence MTA, IRM, Super EBA, ZOE, Control, TCP. 2. MTA showed the least leakage but was not significant with IRM or Super EBA and was significant with control or TCP(p<0.05). 3. TCP had the most leakage and was not significant with control group.

Detection of Adenovirus and Parvovirus in CSF Specimens from Viral Meningitis Adult Patients by Enzyme Immunoassay with Monoclonal Antibody and by Nested - PCR

Viral meningitis and encephalitis are important and serious diseases in young children and adults. There are many causative viruses but it is known that a low percentage of adenovirus (ADV) and parvovirus (PA V) infected individuals develop meningitis or encephalitis. Few reports have been published about central nervous system complications that were rare but fatal. First we used enzyme immunoassay (EIA) with monoclonal antibody to detect ADV antigen (Ag) and PAV Ag in cerebrospinal fluids (CSF) from acute phase of hospitalized adult patients with viral meningitis or viral encephalitis. Second we detected ADV DNA and PAV DNA in the same CSF after cell culture by nested-polymerase chain reaction (PCR). Third we evaluated ADV and PAV dual infection in CSF by EIA and nested-PCR. ADV Ag in CSF by EIA positivity was 42.9% (12l28) and PAV Ag in CSF by EIA positivity was 21.4% (6/28). ADV DNA in CSF by nested-PCR positivity was 89.3% (25/28) and PAV DNA in CSF by nested-PCR positivity was 38.5% (10/26). ADV and PAV dual infection in CSF by 11CSted-PCR was 35.7% (10/28). Detection rate of ADV DNA and PAV DNA in CSF by nested-PCR with viral meningitis or encephalitis adult patients were higher than we expected. Positive detection of nested-PCR was higher than that of EIA with monoclonal antibody for detection of antigens ADV and PAV in CSF with viral meningitis or encephalitis adult patients. Both methods were analnized by the McNemar test.

A Clinical Study of Transient Global Amnesia

I studied 10 patients with transient global amnesia (TGA). On the C-T Brain Scan, 8 patients were normal and 1 patient had an old infarction in the right cerebral hemisphere and 1 patient had right medial thalamic hemorrhage. Electronencephalography was taken in 8 patients who were normal in C-T Brain Scan and the results were normal in all patients. Durations of amnesia were no longer than 6 hours in all patients except 1 patient that had amnesia for 6 days. Associated conditions and diseases with TGA patients were hypertension (in 5 patients), hypertrigliceridemia (in 4 Patients), cardiac arrthmia (in 2 patients), transient ischemic attack (in 1 patient) and diabetes mellitus (in 1 patient).

Olivopontocerebellar Atrophy

Between 1985and 1987, 31 patients with sporadic olivopontocerebellar atrophy (SOPCA) and 3 patients with familial olivopontocerebellar atrophy (FOPCA) were examined in the Neurologic Clinic of Yongdong Severance Hospital. The incidence of the disease among our neurology clinic patients was 0.9% and 3.4% of those patients were admitted. Seventeen of them were men and seventeen women, and their ages of onset ranged from 16 to 75 years (mean, 48.2 years). In comparison with SOPCA, the disease began earlier in FOPCA (mean age, 51.0 VS 19.3 years), but there were no other differences in clinical feature of the disease. Four patients had parkinsonism, one dementia, and one ophthalmoplegia. None presented spinal involvement or abnormal movements. Eight had a coexisting disease; 3, ch(03)nic alcoholism; 2, hypertension; 2, diabetes mellitus; and 1, malignant neoplasm.