“Bad teeth per person” show how many decayed, missing or filled teeth an average 12 year old has in each country. The technical term of the indicator is DFMT for 12-years old and the data is taken from the WHO. We have unfortunately only data for one year. Note that the data in many cases are actually based on estimates for earlier years.
You can head to the site to look at which countries are which.
Dental problems seem to be lowest in the rich countries (good dentists) and poorest ones (no sugar?).