Composite sealants are marketed as specially formulated unfilled resins that presumably cure in a very thin film and with a minimal air-inhibited layer. They are designed to penetrate any microcracks and/or defects that might have been created by finishing procedures. These microcracks may be responsible for some of the wear or staining that occurs with composites. These microcracks could also apply to resin cements. Sealing margins of indirect restorations may prevent or minimize cement washout and even staining.
Step 1 After adjusting the occlusion and polishing a newly placed composite, etch (actually just decontaminate) the restoration and surrounding enamel for 20 seconds, wash, and dry. For sealing old restorations, it is probably best to scrub with pumice or prophy paste prior to applying the etchant.
Step 2 Apply the sealant, disperse with air, and cure for 20 seconds.
"Healing" White Lines
White lines at the margins of Class I restorations are presumably a sign that the polymerization stresses have caused microfractures in the enamel. These microfractures are supposed to be a precursor to microleakage and possibly recurrent caries. To test this theory, Class I restorations were placed in extracted teeth, followed by charting the occurrence of white lines at the margins and examining sections of the teeth for microleakage. While the results of this study were inconclusive, we did find an "association" between their appearance and microleakage.
Composite sealants are thought to be one technique to minimize the effect of these white lines. Therefore, we rated the margins of the restored teeth before and after applying the composite sealant as to each product's ability to "heal" any margins that exhibit white lines. The results are listed in the each product's commentary.