Compatibility between dental adhesive systems and dual-polymerizing composite resins

Degree of conversion and dentin bond strength of light-cured multi-mode adhesives pretreated or mixed with sulfinate agents

The influence of sulfinate agents applied as a dentin pretreatment or a mixture with multi-mode one-step self-etch adhesives (1-SEAs) on the degree of conversion (DC) and micro-tensile bond strength (μTBS) of light-cured 1-SEAs was investigated. 1-SEAs Clearfil Universal Bond Quick (UBQ) or Scotchbond Universal Adhesive (SBU) were applied to dentin in etch&rinse or self-etch mode using various application strategies: 1) no pretreatment, 2) pretreatment with 90 wt% ethanol, 3) pretreatment with a sulfinate agent Clearfil DC Activator (UDC) or Scotchbond Universal DCA (SDC), or 4) a mixture of UBQ+UDC or SBU+SDC. μTBS was measured after 24 h. Additionally, DC was measured using attenuated total reflectance Fourier-transform infrared spectroscopy. Pretreatment with sulfinate agents resulted in the highest μTBS and DC, significantly improving them especially in etch&rinse mode. The mixture of sulfinate agents with 1-SEAs was less effective. Pretreatment with ethanol significantly improved μTBS in etch&rinse mode but compromised μTBS in self-etch mode.

Additive effects of touch-activated polymerization and extended irradiation time on bonding of light-activated adhesives to root canal dentin

STATEMENT OF PROBLEM

The bonding of light-activated adhesives to root canal dentin with an additional touch-polymerization activator has been insufficiently examined.

PURPOSE

The purpose of this in vitro study was to investigate the effect of touch-polymerization activators and extended light-irradiation time on the microtensile bond strength (μTBS) of light-activated adhesives.

MATERIAL AND METHODS

Post cavities were prepared in 50 extracted mandibular premolars and bonded using Prime&Bond Universal (PBU); PBU+Self Cure Activator (SCA); Clearfil SE Bond 2 (SEB); SEB+Clearfil DC Activator (DCA); or Clearfil Universal Bond Quick ER (UBQ). After light-irradiation for 10 or 20 seconds, the post cavities were filled with dual-activated resin core materials. Eight beams were prepared per specimen and subjected to the μTBS test. The μTBS data were analyzed by using 3-way ANOVAs with the Bonferroni correction (α=.05).

RESULTS

The 3-way ANOVAs indicated that the use of touch-polymerization activators (SCA and DCA) significantly increased the μTBS of PBU and SEB in both the coronal (P=.015) and apical (P=.001) regions. The extension of light-irradiation time to 20 seconds significantly improved their μTBS in the apical region (P<.001), but not in the coronal region (P=.09). Light-irradiation for 20 seconds increased the μTBS of UBQ significantly in the coronal region (P=.014).

CONCLUSIONS

Touch-polymerization activators improved the bond strength of light-activated adhesives to root canal dentin, especially when combined with an extended light-irradiation time.

Universal adhesives and dual-cured core buildup composite material: adhesive properties

Dual-cured buildup composites and simplified light-cured adhesive systems are mixed with a chemical activator to prevent the incompatibility between them.

Impact of Recently Developed Universal Adhesives on Tensile Bond Strength to Computer-aided Design/Manufacturing Ceramics

OBJECTIVES

The aim of this investigation was to test the tensile bond strength (TBS) between different computer-aided-design/manufacturing (CAD/CAM) ceramics after conditioning using different universal adhesive systems and resin composite cement.

METHODS AND MATERIALS

Substrates of four CAD/CAM ceramics-1) VITABLOCS Mark II, 2) Initial LRF, 3) Celtra Duo, and 4) IPS e.max CAD (N=648, n=162)-were fabricated. VITABLOCS Mark II and Initial LRF were etched using 9% hydrofluoric acid for 60 seconds, Celtra Duo for 30 seconds, and IPS e.max CAD for 20 seconds. Substrates for conditioning using Monobond Etch & Prime were untreated. The following adhesive systems were used: All-Bond Universal (ABU), Clearfil Universal Bond (CUB), G-Multi Primer (GMP), iBond Universal (IBU), Monobond Etch & Prime (MEP), Monobond Plus (MBP), One Coat 7 Universal (OCU), Prime&Bond Active (PBA), and Scotchbond Universal (SBU). Conditioned substrates were bonded using a resin composite cement (Variolink Esthetic DC), thermal cycled (20,000×, 5°C/55°C), and TBS was measured using a universal testing machine. Data were analyzed using univariate analysis with partial eta-squared, Kolmogorov-Smirnov, Kruskal-Wallis, Mann-Whitney U, and Spearman-Rho tests (α=0.05).

RESULTS

ABU, MEP, and MBP obtained the significantly highest TBS, while CUB, IBU, and OCO resulted in the lowest, regardless of the CAD/CAM ceramic. SBU showed varying TBS results depending on the CAD/CAM ceramic used. ABU, MEP, and MBP showed no impact of CAD/CAM ceramic on TBS values. ABU, GMP, MEP, and MBP showed predominantly cohesive failure types in luting composite, while CUB and OCU demonstrated adhesive failure types.

Bond strength of etch-and-rinse and self-etch adhesive systems to enamel and dentin irradiated with a novel CO2 9.3 μm short-pulsed laser for dental restorative procedures

The objective of this study was to evaluate the influence of CO₂ 9.3 μm short-pulsed laser irradiation on the shear bond strength of composite resin to enamel and dentin. Two hundred enamel and 210 dentin samples were irradiated with a 9.3 µm carbon dioxide laser (Solea, Convergent Dental, Inc., Natick, MA) with energies which either enhanced caries resistance or were effective for ablation. OptiBond Solo Plus [OptiBondTE] (Kerr Corporation, Orange, CA) and Peak Universal Bond light-cured adhesive [PeakTE] (Ultradent Products, South Jordan, UT) were used. In addition, Scotchbond Universal [ScotchbondSE] (3M ESPE, St. Paul, MN) and Peak SE self-etching primer with Peak Universal Bond light-cured adhesive [PeakSE] (Ultradent Products) were tested. Clearfil APX (Kuraray, New York, NY) was bonded to the samples. After 24 h, a single plane shear bond test was performed. Using the caries preventive setting on enamel resulted in increased shear bond strength for all bonding agents except for self-etch PeakSE. The highest overall bond strength was seen with PeakTE (41.29 ± 6.04 MPa). Etch-and-rinse systems achieved higher bond strength values to ablated enamel than the self-etch systems did. PeakTE showed the highest shear bond strength with 35.22 ± 4.40 MPa. OptiBondTE reached 93.8% of its control value. The self-etch system PeakSE presented significantly lower bond strength. The shear bond strength to dentin ranged between 19.15 ± 3.49 MPa for OptiBondTE and 43.94 ± 6.47 MPa for PeakSE. Etch-and-rinse systems had consistently higher bond strength to CO₂ 9.3 µm laser-ablated enamel. Using the maximum recommended energy for dentin ablation, the self-etch system PeakSE reached the highest bond strength (43.9 ± 6.5 MPa).

Influence of an iodonium salt on the properties of dual-polymerizing self-adhesive resin cements

STATEMENT OF PROBLEM

Dual-polymerizing self-adhesive resin cements present mechanical properties that may adversely affect the clinical performance of luted fiber-reinforced posts.

PURPOSE

The purpose of this in vitro study was to evaluate the properties of dual-polymerizing self-adhesive resin cements after the addition of an onium salt.

MATERIAL AND METHODS

The experimental groups were set according to the molar concentration of diphenyliodonium hexafluorphosphate (DPIHFP) (0.5, 1, and 2 mol%). The resin cements were submitted to a push-out bond strength test and assessed for flexural strength (ISO 4049/2009), degree of conversion (Fourier-transformed infrared spectroscopy), depth of polymerization, swelling coefficient, and degradation in solvent. The data were statistically analyzed by ANOVA, Tukey test, Kruskal-Wallis test, Dunn multiple comparison, and paired Student t test (α=.05).

RESULTS

All the RelyX U100 groups with onium salt showed the highest degree of conversion after 24 hours and 7 days (P<.001). However, no statistical difference was found among the BisCem groups (P=.054). The addition of 0.5 mol% DPIHFP increased the push-out bond strength and microhardness of RelyX U100 and promoted less degradation after immersion in solvent. The BisCem control group did not present a statistical difference from the experimental groups in terms of bond strength; the control group and the 0.5 mol% group showed no degradation in solvent. For swelling coefficient and flexural strength, no difference was found between the BisCem groups (P=.067 and P=.173), and the RelyX U100 2 mol% group presented the lower value (P<.001 and P=.048). Depth of polymerization was not statistically different in the experimental groups for either resin cement (P=.999).

CONCLUSIONS

The addition of 0.5 mol% DPIHFP improved the physical properties of dual-polymerizing self-adhesive resin cements.