Body rocking and hitting head

My toddler is almost 17 months and is cutting the bottom two canines along with the top molars still pushing through.

Recently at bedtime he has been rocking on all fours and hitting head into crib or sitting and bumping the back of his head into the crib. It only lasts 30-45 seconds and then he lies down and falls asleep.

I am aware of rhythmic movement disorder but curious if this could be teething related? It just started happening a week and a half ago and only at bedtime. Today during nap he did it once.