OBJECTIVE: The purpose of this study was to investigate the viscoelastic properties related to handling characteristics of composite resins. METHODS: A custom designed vertical oscillation rheometer (VOR) was used for rheological measurements of composites. The VOR consists of three parts: (1) a measuring unit, (2) a deformation induction unit and (3) a force detecting unit. Two medium viscous composites, Z100 and Z250 and two packable composites, P60 and SureFil were tested. The viscoelastic material function, including complex modulus E* and phase angle delta, were measured. A dynamic oscillatory test was used to evaluate the storage modulus (E'), loss modulus (E") and loss tangent (tandelta) of the composites as a function of frequency (omega) from 0.1 to 20 Hz at 23degrees C. RESULTS: The E' and E" increased with increasing frequency and showed differences in magnitude between brands. The E*s of composites at omega = 2 Hz, normalized to that of Z100, were 2.16 (Z250), 4.80 (P60) and 25.21 (SureFil). The magnitudes and patterns of the change of tandelta of composites with increasing frequency were significantly different between brands. The relationships between the complex modulus E*, the phase angle delta and the frequency omega were represented by frequency domain phasor form, E* (omega) = E*e(idelta) = E* 45 degree angle delta. CONCLUSIONS: The viscoelasticity of composites that influences handling characteristics is significant different between brands. The VOR is a relatively simple device for dynamic, mechanical analysis of high viscous dental composites. The locus of frequency domain phasor plots in a complex plane is a valuable method of representing the viscoelastic properties of composites.
Composite Resins

STATEMENT OF PROBLEM: Composite resin-veneered metal restorations can be used as an alternative to porcelain-fused-metal restorations. But, because of the relatively low bond strength of veneering composite to metal framework, various surface treatment methods have been introduced to improve the bond strength. PURPOSE: The object of this study was to compare the shear bond strength of different combinations of each of the two bonding systems and each of the two composite veneering resins to cp-Ti / Co-Cr alloy. MATERIAL AND METHODS: Two resin bonding systems (metal conditioner containing MEPS monomer, tribochemical silicoating system) and two composite resins (Gradia, Sinfony) were tested on cp-Ti and Co-Cr alloy. Then, according to manufacturers' instructions, resin bonding systems and composite resins were applied. All test specimens were divided into four groups for each alloy; I) sandblast + Metal Primer II+ Gradia (MG), II) sandblast + Metal Primer II + Sinfony (MS), III) Rocatec + Gradia (RG), IV) Rocatec + Sinfony (RS). The shear bond strength was determined using a universal testing machine and all data were statistically analyzed with Mann-Whitney test and Kruskal-Wallis test at the significance level of 0.05. RESULTS: The mean (standard deviations) of shear bond strength according to the combinations of two bonding systems and two composite resins to cp-Ti arranged from 16.44 MPa to 17.07 MPa and the shear bond strength to Co-Cr alloy ranged from 16.26 MPa to 17.70 MPa. The result shows that the difference were not statistically significant. CONCLUSION: The shear bond strengths of composite resins to both cast cp-Ti and Co-Cr alloy were not significantly different between the metal conditioner and the tribochemical silicoating system. And no differences in bond strength were found between cp-Ti and Co-Cr alloy.
Alloys* ; Composite Resins*

OBJECTIVES: The aim of this study was to evaluate the surface color of indirect resin restoration according to the layering placement of different shade of incisal composite. MATERIALS AND METHODS: In this study, CIE L*a*b* value of 16 Body composite of Tescera ATL (Bisco, Schaumburg IL,USA) was measured by spectrophotometer (NF999, Nippon Denshuku, Japan), and compared to CIE L*a*b* value of Vitapan shade guide. Nine shade Incisal composite of Tescera ATL were build-up to 1 mm thickness on Body composites inlay block, and CIE L*a*b* value was measured. Incisal composite was ground to 0.5 mm thickness and CIE L*a*b* value was re-measured. Color difference between Body composite and Incisal composites layered on Body composite was calculated as a function of thickness. RESULTS: Color difference between corresponding shade of Tescera Body composite and Vitapan shade guide was from 6.88 to 12.80. L* and b*value was decreased as layering thickness of Incisal composite on Body composite was increased. But, a* value did not show specific change tendency. CONCLUSIONS: Surface color difference between Body composites and Incisal composites layered on Body composite was increased as the layering thickness of Incisal composite increased (p < 0.05).
Composite Resins ; Inlays

No abstract available.
Composite Resins* ; Dental Porcelain*

136 anterior-teeth of 46 patients have been sealed for restoration and monitored. After 24 months, the results are 69.11% good at sealing surface, 67.64% at color, 72.06% at surgery and 58.08% at the integrity of the sea
Incisor ; Composite Resins

Composite resin has been used commonly in dentistry. Bonding the teeth with composite resin was based on two mechanisms: 1) The adhesion between composite and enamel, and 2) the adhesion between composite and dentine. The bond strength of these two mechanisms was compared in 1225 teeth after 2 years of bonding. The results showed that the first mechanism provided stronger bond than the second did.
Composite Resins ; Tooth

112 patients with 1089 teeth were covered directly. The results were evaluated after 6, 12, 18, 24 months of the treatment and have shown that the surface of the composite was good in 70.33% of patients, the fine color of the composite was 68.22%. The rate of anatomical success was 59.68% and the completion of the rear of composite was 67.30%.
Tooth ; Composite Resins ; therapeutics

No abstract available.
Composite Resins ; Dentin

The purposes of this study were to estimate the material properties of the recently developed domestic composite resins for core filling material (Chemical, Dual A, Dual B; Vericom, Korea) and to compare them with other marketed foreign products (CorePaste, Den-Mat, USA; Ti-Core, Essential Dental Systems, USA; Support, SCI-Pharm, USA). Six assessments were made; working time, setting time, depth of polymerization, flexural strength, bonding strength, and marginal leakage. All items were compared to ISO standards. All domestic products satisfied the minimum requirements from ISO standards (working time: above 90 seconds, setting time: within 5 minutes), and showed significantly higher flexural strength than Core Paste. Dual A and B could, especially, reduce the setting time to 60 seconds when cured with 600 mW/cm2 light intensity. All experimental materials showed 6 mm depth of polymerization. Bond strengths of Ti-Core and Dual B materials were significantly higher than the other materials. Furthermore, three domestic products and Ti-Core could reduce the microleakage effectively.
Composite Resins* ; Polymerization ; Polymers

The purposes of this study were to estimate the material properties of the recently developed domestic composite resins for core filling material (Chemical, Dual A, Dual B; Vericom, Korea) and to compare them with other marketed foreign products (CorePaste, Den-Mat, USA; Ti-Core, Essential Dental Systems, USA; Support, SCI-Pharm, USA). Six assessments were made; working time, setting time, depth of polymerization, flexural strength, bonding strength, and marginal leakage. All items were compared to ISO standards. All domestic products satisfied the minimum requirements from ISO standards (working time: above 90 seconds, setting time: within 5 minutes), and showed significantly higher flexural strength than Core Paste. Dual A and B could, especially, reduce the setting time to 60 seconds when cured with 600 mW/cm2 light intensity. All experimental materials showed 6 mm depth of polymerization. Bond strengths of Ti-Core and Dual B materials were significantly higher than the other materials. Furthermore, three domestic products and Ti-Core could reduce the microleakage effectively.
Composite Resins* ; Polymerization ; Polymers