Is this wrong of me?

My boyfriend says it's not but I dunno I felt bad. So my boyfriend every once in a while would get something on his teeth that I haven't seen before so I figured he knew and knew what it was but yesterday I brought it up after 1yeear of dating and I felt really bad cause I feel like he got super self conscious and I didn't do it to say ew gross like I was mostly asking out of curiosity and like I still kiss him and make out with him but I dunno was it wrong for me to point it out? He's had braces and sometimes wears his retainer.