In conventional systems, the resin hardens when exposed to light, the result of a photoactivator
. The U-M solution uses a resin that also has a photoinhibitor, which responds to a different wavelength of light, allowing the two kinds of light to harden the resin at specific points.
The two-photon excitation of the Rose Bengal photoactivator
is induced by a femtosecond titanium sapphire laser (Mira, Coherent, Santa Clara, CA) operating at 780 nm.
was fixed in a dispositive that standardize the focal distance in 10 mm.
Photocuring of monomers is a common method that involves the use of a photoactivator
system that is capable of absorbing ultraviolet or visible radiation wavelengths to convert a monomer into a cross linked system .
(38-40) A range of photoactivators
is available for use in this context.
A number of techniques can be used to modify substrate surfaces (abrasion, photoactivators
, and chemical agents, to name a few) but in recent years research has focused on processes that can change substrate surfaces without altering the general properties of the solids themselves (heat or electrical treatments).