Victoria asked: “Why do patients have a significant reduction in whiteness after the treatment is completed and they return a couple of weeks later?”

Hi Victoria, thanks for the question.

There are a few factors involved in the regression of whitening patients.  All whitening systems, including KöR, have some initial regression over the first 5-10 days.

An analogy:  Think of the white spots in fluorosis cases. Those spots “appear” white because of the millions of missing parts of the enamel. Think of the enamel as a jigsaw puzzle. Imagine missing 20% or more of those pieces. That is sort of what the structure of white spots is like.

Excess fluoride affects the secretory ameloblasts that grow the enamel. So when you have these millions of little “cells” that should have been filled with mineral but were not, light will enter the tooth structure and pass through that empty cell. But when light hits the backside of that cell, the light is reflected directly back to your eye, and will not allow the light to continue through the tooth structure. That is precisely why those white spots look white – it’s an optical illusion.

When whitening, gazillions of microscopic bubbles are formed within the enamel. Those bubbles are filled with ROS (Reactive Oxygen Species) such as the radicals that I discussed in my webinar on The Science of Whitening. They’re gases. Like the open cells in fluorosis white spots, those bubbles throughout the tooth structure reflect light back at our eye. And it often takes 5-10 days for all of those bubbles to finally exit the teeth. Once the bubbles exit the tooth structure you see the “REAL” whitening.  This would be “short-term regression”.

Whitening systems that don’t TRULY get the teeth really white will show huge regression.

However, you can also see “long-term regression”.  Long-term regression can be due to the accumulation of additional stain.  But it is also associated with the chromophores found within the stain/color molecules trapped within the enamel matrix. Remember, chromphores are a certain type of intramolecular bond between atoms.  These chromophores absorb various wavelengths of visible light, making the teeth appear darker.  So it’s the chromophores that cause teeth to appear darker. 

During initial whitening, you’ve broken apart chromophores to make the teeth whiter. But intramolecular chromophores are like magnets. You can pull magnets apart, but if you get them too close together again, they tend to SNAP back together. The same thing happens with chromophores, which is why we include periodic at-home whitening maintenance to totally prevent this sort of long-term regression.

If you have any other questions about this or anything else, feel free to contact your KöR rep at (949) 713-0909 or toll free at (866) 763-7753

Very best regards,


Dr. Rod Kurthy

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