The Evolution of Esthetic Fillings

May 8, 2020

It’s hard to believe that all I’m about to tell you has happened in my dental practice lifetime.  We’ve undergone a revolution in how we restore front teeth that are decayed or broken in sth space of the last 45 years.

The approach to restoring front teeth before the 1960’s was to prepare the cavities so that the edges would be hidden or camouflaged.  By shaping the edges of the fillings to follow the contours of the teeth, the silver or gold wouldn’t be picked up by the eye as readily. Some more esthetic materials were tried such as silicate cements but they weren’t really tooth colored and didn’t last very long in the very tough environment of the mouth.

The 1960’s saw the ushering in of the plastic age.  Acrylic filling materials started to become available but they were just unfilled resin that had little strength, poor margins due to shrinkage when they cured, and no bonding ability to tooth structure.  Silver amalgam and gold remained much better choices overall.  In the early 70’s, filled composite resins made their debut.  They were acrylic resin with hardened chunks of resin as filler for strength, sort of like the rocks or aggregate in concrete that gives it it’s strength.  These had less shrinkage and better strength but still weren’t bonded and had to be mixed in 2 parts, a base and a catalyst, which led to porosities in the material that let them stain more easily.  And since the fillers were relatively large (20-30 microns), they didn’t polish very well.

By the mid 70’s things really started getting interesting.  The first bonding materials became available for enamel and the filler particles became smaller, making for a smother final finish.  Along with that were the first light cured materials.  Initially they were UV cured and had many limitations so they never really were widely used, but the idea of light activated fillings began here.  By the next decade, bonding of both enamel and dentin was advanced and the filler particles became smaller (5 microns).  But the huge advance was the introduction of light cured materials.  Visible blue light (450-550 nanometer wavelength) polymerizing of filling materials became the norm.  No more mixing, better bonding, multiple shades and highly polishable, these quickly were adapted by almost everyone.

As we progress, the bonds are getting stronger, the amount of shrinkage with polymerization has been minimized, and the shades and light refraction has made these look more and more like natural teeth.  I often get asked when I might retire from dentistry.  My standard answer is, “Why would I retire now?  It’s just getting good!”