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accomplished because of lack of isolation or cooperation. Total-etch technique
is compatible with universal adhesives because the acidity of the monomer
is mild and overetching will not occur. The selective-etch technique of
phosphoric acid etching on the enamel only shows very favorable increased
bond strengths with universal self-etch adhesives.27,28

Mechanism and reliable use of self-etch adhesive
Futurabond U by Voco is a universal self-etch adhesive supplied in a
single-dose system. The distinct advantages of a single-dose system include a
consistent mix and reliable chemistry each time a package is opened, as well
as superior infection control.
With multibottle or single-bottle systems, results can be unpredictable,
depending on whether the bottle has been shaken properly, how much product
is dispensed and, thanks to the evaporation of solvent after a bottle's been
opened, the changed chemistry of the product when the bottle is almost empty.
To understand the mechanism of bonding, we must understand the properties
of the tooth structure and the resin composite to which we are bonding. Tooth
structure is inherently wet so, even when it's etched and dried, moisture will
seep up from dentinal and crevicular fluids.
Resin composite is completely hydrophobic. We require an adhesive that
can perform in both hydrophilic (water-loving) and hydrophobic (water-hating)
manners. Futurabond U contains acidic monomers, pH 2.3, which offer two
polarities on the same molecule. The polarities are hydrophilic on one end to
allow a bond to the hydrophilic tooth structure, and hydrophobic on the other
to allow bond to the hydrophobic composite.
The acidic monomer etches the enamel surface of the tooth structure by
dissolving calcium ions out of the hydroxyapatite and creates microtags, or a
roughened surface. Then the monomer can attach to the enamel surface. The
action of the acidic monomer to dentin is different. The acidic monomer applied
to dentin causes calcium to be dissolved-the dentin tubules are now opened
and collagen fibers are exposed.
Futurabond U creates a hybrid layer on the dentin. During this process,
the acidic product will rise to a neutral level. Gently air-drying for five seconds
will evaporate the solvents, which are composed of water and ethanol, from the
adhesive and fix the hybrid layer. Light-cure for 10 seconds with a minimum
of 500 milliwatts per square centimeter. The light cure activates cross-linking
monomers that connect the acidic adhesive monomers to the composite.

Fig. 4

Fig. 5

Clinical case 1
A 3-year-old patient presented with multiple carious lesions in all quadrants.
Dental restorations were carried out with patient under general anesthetic.
Quadrant 4, teeth #84 (S) and #85 (T) each were cavitated on the occlusal
surface into dentin (Fig. 1).
The quadrant was isolated with an 8A ivory clamp and slot-style rubber dam,
and a conservative outline was prepared using an NSK high-speed handpiece
and a 330 FG bur. Caries was excavated with an NSK slow-speed handpiece
and 6 and 8 round burs (Fig. 2) followed by a selective-etch technique with
phosphoric acid (Fig. 3).
Futurabond U was applied to the preparation and the entire occlusal surface
(Fig. 4). Teeth were restored with Admira Fusion by Voco, an all-ceramic-based

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