A comparative in vitro study of visible light‐cured sealants

Abstract

The introduction of visible light polymerization in dentistry led to the development of a new generation of pit and fissure sealants. The purpose of this study was an overall evaluation of some in vitro characteristics of four new sealants (Delton LC, Helioseal, Pentra-Seal and Visioseal) in comparison with a chemically cured control (Delton). The results indicate that the monomer systems utilized in the new materials have already been used in dental polymer technology. The relatively new monomers TCDDMA/TCDMA were identified in one product. Camphoroquinone is used as a photoinitiator in all the light-cured systems which, after 40 s exposure, present better conversion than the control. The extent of oxygen inhibition was considerably reduced in the new sealants and the surface hardness was enhanced. Great differences were obtained in the penetration coefficient values; these, however, did not affect the enamel retention capacity of the materials tested. Consequently, light-cured sealants should be considered to be strongly compatible with the conventional chemically cured sealants from a laboratory aspect until more clinical evidence is available for their effectiveness in the prevention of pit and fissure decay.

Depth of cure of sealants polymerized with high‐power light emitting diode curing lights

“…In addition to the opacity of the sealant material affecting the depth of cure, the chemical composition of the material may have played a role as well. CQ is the photoinitator for both FluroShield and Delton LC Opaque, so it is more likely that the difference seen in their curing performance is related to the color of the material (clear vs opaque). UltraSeal XT plus does not disclose its light activator.…”

Effect of the reducing agent on the oxygen‐inhibited layer of the cross‐linked reline material

“…Large amounts of oxygen are one of the inhibitors or retarders of the polymerization. This leads to the formation of an unpolymerized surface layer of the resin, which can be examined by microscopic techniques (Ruyter, 1981;Lekka et al, 1989;Rueggeberg & Margeson, 1990;Vallittu, 1997;Yatabe et al, 1999). The application of the reducing agent removed oxygen from the free radical, allowing the polymerization to continue.…”

“…The observation of the surface oxygen-inhibited layer of the reline material was performed according to a modified method presented by Lekka et al (1989). The material (0·05 mL) was placed between a microscope slide and a cover slip after mixing according to the manufacturer's instruction.…”

Sealants Revisted: An Update of the Effectiveness of Pit-and-Fissure Sealants

“…For instance, Lekka et al [1989] reported similar physical properties and shear bond strengths when they compared four visible light initi ated sealants to a chemically cured control, and they found less oxygen inhibition with the light-activated sys- terns which they felt was clinically advantageous. Con versely, Atwan and Sullivan [1987] reported significantly less tensile bond strengths for a visible light activated sea lant as compared with a chemically initiated one when tested on primary and permanent extracted teeth.…”