Effect of polymerization protocol on the degree of conversion of photo- and dual-polymerized self-etch adhesives

Abstract

(2016). Effect of polymerization protocol on the degree of conversion of photo-and dual-polymerized self-etch adhesives. Journal of Adhesion Science and Technology, 30(3) Bond Universal DC, 3M ESPE) were tested. All adhesives were applied on potassium bromide pellets (KBr) following the manufacturer's instructions. The KBr pellets were divided into 10 experimental groups for the photo-polymerized adhesives and 12 experimental groups for the dual-polymerized adhesives according to the two levels of the study, Level 1: Polymerization protocol and Level 2: Adhesive system. For the photo-polymerized adhesives, the adhesives were polymerized either at 1 mm or 10 mm from the KBr pellets. For the photo-polymerized adhesives, the adhesives were photo-polymerized either at 1 mm or 10 mm distance or polymerized chemically. The DC% of the unpolymerized and polymerized adhesives was assessed using Fourier transform infrared spectroscopy (FTIR). Data were analyzed using two-Way ANOVA to evaluate the effect of polymerization protocol, adhesive system and their interaction on the DC% of the self-etch adhesives. For the photo-polymerized and dual-polymerized adhesives, one-Way ANOVA and Tukey HSD post hoc test was used to evaluate the effect of adhesive system within each polymerization protocol and the effect of polymerization protocol within each adhesive for the dual-polymerized adhesives (p=0.05). Student t-test was used to compare the effect of polymerization distances within each photo-polymerized adhesive. For both photo-and dual-polymerized adhesives, the polymerization protocol and adhesive system had a significant effect on the DC (p=0.000). The interaction between the two factors (polymerization protocol and adhesive system) revealed also a significant effect on the DC% of the different 3 adhesives (p=0.000). Polymerization distance of 1 mm showed significantly higher DC% compared to 10 mm distance. When the dual-polymerized adhesives were left to set chemically, they showed the lowest DC% among all polymerization protocols. DC varied depending on the chemical composition of the self-etch adhesives. The tip of the polymerization device should be positioned as close as possible to the surface to achieve higher DC% of the tested adhesives. Photo-polymerization of the dualpolymerized self-etch adhesives is a mandatory step to improve their DC.

The impact of application mode of three universal adhesives with different chemical compositions and curing techniques on their micro shear bond strength to dentin

“…Hence, dual cured adhesive systems were developed by adding chemical initiations as organic peroxide and aryl sulfinate salt activators to be mixed with the adhesive just before application which allowed the adhesive system to cure in the absence of light 28 .Still, the dual cured adhesive polymerization starts basically by light activation and should continue chemically by the self-cured activators. In the areas were light proved to be deficient, radical generation was spontaneous and non-controllable which was reflected by lower bond strength values [29][30] To counteract this major drawback, self-cured adhesives were developed which relayed totally on chemical polymerization through the presence of benzoyl peroxide as chemical initiator and tertiary amine as co-initiator 31 . Furthermore, many studies reported the incompatibility between dual and self-cured resin composites with simplified adhesives 32 ' 33 .…”

Micro-tensile Bond Strength of Three Different Dual Cure Resin Composites Bonded to Dentin

“…Under acidic conditions, the catalyst reacts with the amines of the dual-polymerized composite, making them more reactive to the benzoyl peroxide activator (BPO), which is responsible for the chemical polymerization Mansoura Journal of Dentistry Alzrouq et al process in resinous materials. 25 According to SEM Observations in the All-bond universal adhesive Produced a thick HL with little variable length of RT with the higher bond strength. Its acidity causes the dissolution of smear plugs and opening of tubular permeability and facilitates penetration, impregnation, polymerization, and entanglement of monomers with the underlying dentin to form hybridized complexes.…”

CAD/CAM Surface Treatment And Type Of Adhesive Affect CAD/CAM Composite Bonding To Dentin

“…The bond strength was dropped, when simplified light-cured adhesives were used with dual-cured or self-cured resin cement 25 . Hence, manufactures introduced self-curing activators that are either incorporated in the formulation of the universal adhesives or presented as a separate bottle to be mixed with the light cured adhesives 13 . Unfortunately, this chemical incompatibility is not always reversed by adding the self-cured activator 26 .…”

“…The incompatibility between simplified adhesives and dual-and self-cured resin composites was extensively discussed in the previous studies [9][10][11][12] , which encouraged dental manufacturers to switch simplified light-cured adhesives to dual-cured ones. This is achieved by providing the so-called "selfcured activators" to be mixed with the light-cured adhesive [13][14][15] . The dual-cured adhesives polymerize basically by light activation, which in areas of difficult light access, their bonding effectiveness could be compromised 16 .…”