Influence of the Light Curing Tip Distance and Material Opacity on Selected Physical Properties of a Pit and Fissure Sealant

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Purpose: The purpose of this study was to evaluate the influence of the light curing to distance and material opacity on hardness (KHN), degree of conversion (DC), and crosslink density (CLD) of a resin-based fissure sealant (Fluroshield). Methods: One-millimeter-thick white opaque and clear sealant specimens, photoactivated at 1-, 2-, and 3-mm distances, were fabricated (8 groups, N=5). KHN and DC were evaluated 24 hours after polymerization. Specimens were subjected to a new KHN reading after 24-hour immersion in absolute ethanol to indirectly assess the CLD. Results: Samples of clear sealant cured at longer distances presented lower KHN, although there were not differences between opacities at all distances. The mean DC of the opaque white material, however, was lower than that of the clear one at higher distances. There were no differences among CLD for all experimental conditions analyzed. Conclusions: KHN of the clear sealant was affected by increased distances. The clear sealant showed higher DC at increased distances, although CLD was not influenced by the factors under study. Since physical properties of sealing materials are directly related to their clinical efficacy, the clear sealant tested may present a better clinical performance than the opaque one. (Pediatr Dent 2011;33:505-9) Received April 20, 2070 vertical bar Last Revision July 4, 2010 vertical bar Accepted July 7, 2010337505509Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [07/02800-3