“It can reduce the risk of tooth decay because more of the tooth is exposed for brushing and flossing,” says Harms. The surgery can usually be completed in 30 minutes to an hour. Disadvantages of crown lengthening: This cosmetic dentistry treatment can be pricey. Expect to pay $1,000 to $4,000 for crown lengthening. If the procedure is medically warranted, insurance should pick up some of cost, says Harms. As with other types of cosmetic surgery, you may experience swelling and pain afterwards.