No abstract available.
Collodion*

No abstract available.
Collodion*

The purpose of this study was to compare the root canal shaping ability of 4 rotary NiTi instruments in simulated root canals. For the preparation of thirty two curved root canals, Mtwo instruments using "single length"technique, and Profile, ProTaper Universal, and K3 using crown-down technique (N = 8) were used. All canal samples were prepared by reaching an apical canal size of #30. Pre- and post-instrumentation digital images were recorded and an assessment of canal shape was determined using a computer image analysis program SigmaScan Pro (Systat Software Inc., San Jose, CA, USA). The changes of the dimension of inner walls of canals, (2) the changes of the dimension of outer walls of canals, and (3) the centering ratio were measured at 7 measuring points, and then data were statistically analyzed using one-way ANOVA and Duncan's test. The results were as below; 1. The root canal shaping ability of Profile was significantly faster than that of other rotary NiTi instruments (p < 0.05). 2. The deformation and fracture of all instruments used for this study were not experienced. 3. In the degree of changes of the dimension of inner walls of canals, Profile demonstrated the lowest changes of the dimension of inner walls of canals except at the measuring points of the 1 and 2 mm (p < 0.05). However, the ProTaper Universal showed the highest changes of the dimension of inner walls of canals at all measuring points (p < 0.05). 4. In the degree of changes of the dimension of outer walls of canals, Mtwo demonstrated the lowest changse of the dimension of outer walls of canals except at the measuring point of the 1 mm (p < 0.05). However, Profile exhibited the highest changes of the dimension of outer walls of canals at the measuring points of 3 and 4 mm and ProTaper Universal and K3 showed the largest changes of the dimension of outer walls of canals at the measuring points of 1, 2, 6, and 7 mm (p < 0.05). 5. In degree of centering ratio, Profile demonstrated the least centering ratio comparing with the centering ratio shown by other NiTi instruments at the measuring points of 1, 4, 5, and 6 mm. Results suggest that in the coronal part of canal preparation, active cutting files such as ProTaper Universal may efficiently flare the canal orifice and form a better taper, and in the apical part of the canal, files which have a better centering ability such as Profile may maintain the original canal curvature and reduce the shaping time.
Collodion ; Dental Pulp Cavity

PURPOSE: The purpose of this research was to evaluate the shear bond strength between zirconia core and veneer ceramic after surface treatment. MATERIAL AND METHODS: Zirconia cores (N = 40, n = 10, 10 mm x 10 mm x 3 mm) were fabricated according to the manufacturers??instructions and ultrasonically cleaned. The veneering ceramics (thickness 3 mm) were built and fired onto the zirconia core materials. Four groups of specimens with different surface treatment were prepared. Group I: without any pre-treatment, Group II: treated with sandblasting, Group III: treated with liner, Group IV: treated with sandblasting and liner. The shear bond strength was tested in a universal testing machine. Data were compared with an ANOVA and Scheffe post hoc test (P = .05). RESULTS: The shear bond strength of group VI was significantly higher than the other groups. CONCLUSION: Both mechanically and chemically treated simultaneously on zirconia core surface influenced the shear bond strength between the core and veneering ceramic in all-ceramic systems.
Ceramics ; Collodion ; Fires ; Zirconium

PURPOSE: The objective of this study was to compare the fracture toughness (KIc) obtained from the single edge V-notched beam (SEVNB) and the fractographic analysis (FTA) of a glass-infiltrated and a zirconia ceramic. MATERIALS AND METHODS: For each material, ten bar-shaped specimens were prepared for the SEVNB method (3 mm x 4 mm x 25 mm) and the FTA method (2 mm x 4 mm x 25 mm). The starter V-notch was prepared as the fracture initiating flaw for the SEVNB method. A Vickers indentation load of 49 N was used to create a controlled surface flaw on each FTA specimen. All specimens were loaded to fracture using a universal testing machine at a crosshead speed of 0.5-1 mm/min. The independent-samples t-test was used for the statistical analysis of the KIc values at alpha=0.05. RESULTS: The mean KIc of zirconia ceramic obtained from SEVNB method (5.4 +/- 1.6 MPa.m1/2) was comparable to that obtained from FTA method (6.3 +/- 1.6 MPa.m1/2). The mean KIc of glass-infiltrated ceramic obtained from SEVNB method (4.1 +/- 0.6 MPa.m1/2) was significantly lower than that obtained from FTA method (5.1 +/- 0.7 MPa.m1/2). CONCLUSION: The mean KIc of the glass-infiltrated and zirconia ceramics obtained from the SEVNB method were lower than those obtained from FTA method even they were not significantly different for the zirconia material. The differences in the KIc values could be a result of the differences in the characteristics of fracture initiating flaws of these two methods.
Ceramics ; Collodion ; Zirconium

No abstract available.
Collodion ; Influenza, Human

PURPOSE: The aim of this study was to evaluate the effect of mechanical, chemical surface treatments on the zirconia-to-resin cement shear bond strength (SBS). MATERIALS AND METHODS: Eighty zirconia discs (Lava, 3M ESPE) and eighty zirconia/alumina composite (Zirace, Acucera) were embedded in an epoxy resin base. Zirconia discs were randomly divided in to four treatment groups(10 for each manufacturer): 50 microm Al2O3 sandblasting (S50),110 microm Al2O3 sandblasting (S110), 50 microm Al2O3 and primer (Z-Prime Plus, Bisco Inc) (S50z) and 110 microm Al2O3 and primer (Z-Prime Plus) (S110z). Two resin-based luting cements (Calibra, Panavia F) were used to build 2 mm-diameter cylinders onto the zirconia. After 24 h of storage in water, SBS testing was evaluate using a universal testing machine.Bond strength data were analyzed with one-way ANOVA, two-way ANOVA test and post hoc comparison was done using Tukey test (alpha=.05). RESULTS: Groups using primer showed the high shear bond strength. The groups that did not use primer presented lower shear bond strengths. CONCLUSION: The use of primer (Z-Prime Plus, Bisco) had significantly higher shear bond strengths.
Collodion ; Resin Cements ; Water ; Zirconium

OBJECTIVE: We investigated the deficit in the recognition of facial emotions in a sample of medicated, stable Korean patients with schizophrenia using Korean facial emotion pictures and examined whether the possible impairments would corroborate previous findings. METHODS: Fifty-five patients with schizophrenia and 62 healthy control subjects completed the Facial Affect Identification Test with a new set of 44 colored photographs of Korean faces including the six universal emotions as well as neutral faces. RESULTS: Korean patients with schizophrenia showed impairments in the recognition of sad, fearful, and angry faces [F(1,114)=6.26, p=0.014; F(1,114)=6.18, p=0.014; F(1,114)=9.28, p=0.003, respectively], but their accuracy was no different from that of controls in the recognition of happy emotions. Higher total and three subscale scores of the Positive and Negative Syndrome Scale (PANSS) correlated with worse performance on both angry and neutral faces. Correct responses on happy stimuli were negatively correlated with negative symptom scores of the PANSS. Patients with schizophrenia also exhibited different patterns of misidentification relative to normal controls. CONCLUSION: These findings were consistent with previous studies carried out with different ethnic groups, suggesting cross-cultural similarities in facial recognition impairment in schizophrenia.
Collodion ; Ethnic Groups ; Humans ; Schizophrenia

PURPOSE: The aim of the study was to evaluate the effect of 3 silicone primers and 3 surface characterization of acrylic resin surface on bond strength between silicone elastomer and acrylic resin. MATERIALS AND METHODS: 96 Cosmesil silicones bonded to heat-curing acrylic resin were fabricated with the dimension of 75 x 10 x 3 mm. The 3 primers used in this study were G611 platinum primer, A-330 Gold platinum primer, and cyanoacrylates resin. Specimens without primer were used as control. The 3 types of surface characterization done were retentive holes with 1.5 mm in diameter and 0.5 mm deep, retentive beads of 0.6 mm diameter and the third type which was plain without any characterization. The specimens were then checked for bond strength by subjecting them to 180degrees peel test on a universal testing machine. The obtained results were then subjected to statistical analysis using 2-way ANOVA and Scheffe multiple post hoc procedures. The statistical significance was set at 5% level of significance. RESULTS: The maximum bond strength was seen for samples in which A-330G primer was used followed by G611 primer. The control group showed the minimum bond strength. Surface characterization of retentive holes increased the bond strength considerably as compared to retentive beads and samples without any surface characterization. CONCLUSION: Within the limitations of the study, A-330G primer was more compatible with Cosmesil M511 silicone and has better bonding of Cosmesil to acrylic resin. Retentive holes made on acrylic surface increased the bond strength considerably than those without any surface characterization.
Collodion ; Cyanoacrylates ; Platinum ; Silicone Elastomers

PURPOSE: This study evaluated the bonding strength of direct relining resin to Co-Cr denture base material according to surface treatment and immersion time. MATERIALS AND METHODS: In this study, Co-Cr alloy was used in hexagon shape. Each specimen was cut in flat surface, and sandblasted with 110 microm Al2O3 for 1 minute. 54 specimens were divided into 3 groups; group A-control group, group B-applied with surface primer A, group C-applied with surface primer B. Self curing direct resin was used for this study. Each group was subdivided into another 3 groups according to the immersion time. After the wetting storage, shear bond strength of the specimens were measured with universal testing machine. The data were analyzed using two-way analysis of variance and Tukey post hoc method. RESULTS: In experiment of sandblasting specimens, surface roughness of the alloy was the highest after 1 minute sandblasting. In experiment of testing shear bond strength, bonding strength was lowered on group B, C, A. There were significant differences between 3 groups. According to period, Bonding strength was the highest on 0 week storage group, and the weakest on 2 week storage group. But there were no significant differences between 3 periods. According to group and period, bonding strength of all group were lowered according to immersion time but there were no significant differences on group B and group C, but there was significant difference according to immersion time on group A. CONCLUSION: It is useful to sandblast and adopt metal primers when relining Co-Cr metal base dentures in chair-side.
Alloys ; Collodion ; Denture Bases ; Dentures ; Immersion ; Methacrylates