Some of it might be a little intense for the dentist. Most people do not like being there to begin with. It would have to be the parts that are gentle, nothing too bombastic. I’d suggest music from the first act: Rodolfo’s Che gelida manina – “What a cold little hand” and Mimì‘s Sì, mi chiamano Mimì – “Yes, they call me Mimì” or the duet with both Rodolfo and Mimì, O soave fanciulla – “Oh gentle maiden”. Good luck!