I'm of course still using my fluouride trays every night, now 7 years out of treatment. But I note that they've been developing dark spots that I can't seem to remove. My instinct is to think that these are biological in nature - perhaps bacteria colonies?

I had been using an abrasive cleaner on them but my dental hygienist suggested discontinuing this as it could damage the plastic, and in fact encourage the growth of bacteria.

I can remove most of the toothpaste residue with a firm brushing. But the spots, they elude me.

Anyone have any suggestions?
Thanks

David 2
SCC of occult origin 1/09 (age 55)| Stage III TXN1M0 | HPV 16+, non-smoker, moderate drinker | Modified radical neck dissection 3/09 | 31 days IMRT finished 6/09 | Hit 15 years all clear in 6/24 | Radiation Fibrosis Syndrome kicked in a few years after treatment and has been progressing since | Prostate cancer diagnosis 10/18