Can I book doctor and dentist appointments for Chol Hamoed Sukkos if there is really no other time available for my family and I to go?
One should do every attempt to schedule doctor and dentist appointments that they not take place on Chol Hamoed. Where it’s impossible, one may book doctor and dentist appointments for Chol Hamoed if necessary. However, this applies only to appointments to deal with existing issues such as pain or saving the tooth, or to check a concern which can get worse if delayed, but not for standard check ups, nor for straightening the teeth or cleanings. You may visit the dentist to check if someone is developing cavities, but not [just] because its time for the yearly visit.
If its a highly skilled doctor, and not scheduling the appointment for Chol Hamoed will cause one to lose a chance of being seen by such a professional, one may schedule for Chol Hamoed.
ראה שו”ע או”ח סי’ תקל”ב סעי’ ב’, שו”ת אגרות משה או”ח ח”ג סי’ ע”ח, שש”כ סו, הערה פח וצב. ועוד