Physico-Chemical Approach of Sealants Infiltration and Spreading Mechanisms

Objectives: Most sealants are hydrophobic except one, Embrace™ which is claimed to be of hydrophilic nature so that it can be placed on wet enamel. Does the hydrophilic character influence the depth of penetration or the microleakage? What is the influence of the enamel state (wet/dry) on the sealing and the wettability? Methods: 2 sealants were tested: Helioseal®F (Ivoclar-Vivadent) and Embrace™ (Pulpdent). 1/ The polar and dispersive components of these sealants' surface energy were calculated with the Digidrop(GBX). 2/ Polished enamel surfaces were created on the proximal faces of 15 extracted human molars. Each sample was divided into 4 parts devoted to the spreading study of Embrace™ or Helioseal®F on wet or dry enamel. The record was done with the Digidrop. The results were analysed using a parametric test (ANOVA-2). 3/ 40 molars were divided into 4 groups: depending on the group, the teeth were sealed with Embrace™ or Helioseal®F, on wet or dry enamel. After sealing, the samples were thermocycled, stained with a methylene blue solution and embedded. 4 sections were made per sample to assess both sealant penetration (% of the length of the fissure) and the microleakage (scores method). For penetration the results were analysed using ANOVA-2 whereas the results of microleakage were analysed using a Chi-Square-test. Results: 1/ Embrace™ presents a clearly defined hydrophilic character when compared to Helioseal®F. 2/ Embrace™ presents a better spreading than Helioseal®F (p<0,01) but there is no difference between wet or dry enamel (p=0,9). 3/ There is no difference of penetration between the two sealants (p=0,95). Humidity decreases significantly their penetration. (p=0,01). Conclusions: Sealing and material penetration look better when the sealant is applied on dry enamel. The different measures obtained on both biomaterials as far as hydrophilicity and wettability are concerned have no direct influence on material penetration or microleakage.