Is it wrong to notice or ask someone about their new teeth?

Throw em a curve ball and say you like their new pants. 👖

Most people I know that have had them done are happy to be complimented -do it!

Maybe be vague...say something like "There's something different about you..."

Then if/when they mention it, say "Yes! They look great....very white and straight..."

That way its not so obvious that you noticed.

"Nice InvisAlign, by the way."
"You can see it?"
"Well yeah, it's just a name...it's not magic".

Turkish Teeth...

prestained w/Turkish coffee?

If they literally are gleaming white, presumably the wearer is expecting people to notice 😬