Mj. Hicks et al., Surface topography and enamel-resin interface of pit and fissure sealants following visible light and argon laser polymerization: An in vitro study, J DENT CHIL, 67(3), 2000, pp. 169
This in vitro study compared the effects of visible light and argon laser p
olymerization of pit and fissure sealants on surface topography and the ena
mel-sealant interface. Twenty caries-free human molars and premolars underw
ent soft tissue debridement and a fluoride-free prophylaxis. Fluoride-relea
sing sealant (UltraSeal XT Plus, South Jordan, UT 84095) was placed on the
occlusal surfaces per the manufacturer's instructions, but underwent either
visible-light polymerization fur 30s (n=10), or argon laser polymerization
(0.231J/cm(2)) for 10s (n=10). The sealed teeth were thermocycled (500 cyc
les, 5 degrees to 50 degrees C) in artificial saliva. Surface morphology wa
s evaluated by SEM. The teeth were sectioned for polarized light and SEM ev
aluation of the enamel-sealant interface, with two sections per tenth prepa
red for SEM. Phosphoric add was used to unmask the enamel-sealant interface
with one section; while the other section was not exposed to the phosphori
c add. Surface morphology of the sealant material was similar with both vis
ible light and argon laser polymerization; however, there Lt as a tendency
for occasional areas of mild, focal cratering of the sealant sur face with
laser-curing. The unction between sealant and adjacent unsealed enamel was
a relatively smooth transition without gays, microspaces, crazing, exfoliat
ive changes, or microfractures with both visible Light and laser cured seal
ants. Acid treatment of the sections revealed resin tags which extended int
o the adjacent enamel for a considerable distance on SEM examination. The r
esin tags were similar in length and morphology with both visible light and
argon laser curing. The enamel-sealant interface with visible light and la
ser curing showed intimate contact between the sealant and etched occlusal
enamel with close apposition of the sealant. No microspaces were identified
between the sealant and the occlusal enamel. An intact, interdigitating in
terface between a sealant and the adjacent etched enamel provides the first
line of defense against a cariogenic challenge. Visible-light and argon la
ser curing allows for an intimate enamel-sealant interface without microspa
ces and protects sealed enamel from cariogenic challenges. The benefit of a
rgon laser polymerization, fluoride release and mechanical protection of se
alant material may provide improved caries resistance in sealed pits and fi
ssures and adjacent nonsealed enamel surfaces.