Something weird is going on with my dogs’ teeth

Yesterday, I got home and noticed my boy Chihuahua is missing a tooth at the top

Row. He’s approaching 8 years old and had pretty bad teeth / breath when I adopted him , and I’ve heard chihuahuas can have dental problems

Flash forward to today and my

Girl Chihuahua (same age) was playing around and I saw something weird in her mouth. I go to inspect only to discover she’s missing a tooth in her bottom

Row ! (Same tooth, different row) ! Her dental health has always been great

What on earth could explain this?

\- I considered their food but nothing like this has ever happened before and what are the odds it would happen at the same

Time

\- maybe the two of them rough housing together caused a clash and they knocked each others teeth out ? (But I don’t see anything chipped or

Left over. Seems like each had a loose tooth and it came out

Any ideas ??