My learning point today arose out of the belated research into the kind of filling my dentist recently used in two of my teeth. My dentist pays me the respect of assuming (a) that I care about what he is doing in/to my mouth and (b) that I will understand what he is talking about. He encourages me to google things.
So I do.
The fillings he recently gave me are a semi-permanent solution which will probably have to be replaced by crowns in about 4-5 years.
They are called glass ionomers and are made, believe it or not, of a "mixture of acrylic acids and fine glass powders". One of the major benefits is the additional protection they offer by releasing a small amount of fluoride. Another is that less of the tooth needs to be drilled away than is the case with amalgam fillings.
I'll spare you a picture of my teeth to go with this post!