Our now 3 year old had a cavity & had a crown placed on his front, top tooth. a year later, he now has an abscess above that tooth. if we treat with antibiotics, how long until it comes back? trying to buy time before extraction to avoid anesthesia?

Tooth Abscess: Antibiotics will only abate the symptoms of an infection for a short while... that tooth appears to need a "baby root canal". The secondary incisor will not erupt until about 7 years old, so you're not going to buy four years worth of time with antibiotics. Speak to your child's dentist regarding options.

Infection: Antibiotic will abate, not cure, infection. Meds will only be effective until discontinued. Infection is at risk of causing permanent damage to partially formed permanent incisor that is not due to erupt until about age 7. Choices are either extraction or root canal treatment. As either procedure can interfere with permanent tooth eruption, guidance by Pedodontist or Orthodontist would be prudent.