Unbiased oral health information

Procedures

Onlays

Disadvantages & risks

The following are disadvantages and potential risks of this procedure. You may also require some or all of the additional procedures listed to treat your condition, which can add time and expense.

  • Onlays and crowns are relatively expensive, costing roughly four times what a four-surface filling may cost.
  • Traditionally, onlays and crowns require two visits to complete. Often, this means being "numb" at both appointments. Some dental practices are now offering computer-milled inlays, onlays and crowns, which are delivered the same day the tooth is prepared, eliminating the need for a second appointment; however, these may not be appropriate for all teeth.
  • Preparing a tooth for an onlay or crown involves reducing the sides of a tooth and its biting surface. Depending on how thick the remaining walls of the prepared stump are, the tooth's structural integrity can be significantly compromised, reducing its long-term prognosis.
  • Inflammation and/or infection from the preparation procedures can occur, and may be more likely with ceramic onlays and crowns, because it is necessary to remove more tooth structure than for metal ones. This is because porcelain must be thicker than metal to have comparable strength. Studies aiming to quantify the risk of tooth abscess following crown preparation have shown an abscess rate of about 10%.
  • If the tooth being prepared is vital (i.e. "alive"), it will normally be anesthetized. Local anesthetic has risks of its own, which are generally considered minor compared to the advantages of having the procedure performed comfortably.
  • Inlays, onlays and crowns can fall out and be lost, requiring replacement.
  • Ceramic and composite resin inlays, onlays and crowns can chip, requiring repair or replacement.
  • Leakage can occur along the interface between an inlay, onlay or crown and the prepared tooth (i.e. the "margin"), leading to sensitivity and decay.
  • All dental procedures can produce lip dryness, chapping and cracking. Some patients develop cold sores following dental treatment. Some degree of post-operative discomfort frequently accompanies tooth preparation, including tenderness to biting and cold which is normally temporary. Some studies have shown prolonged sensitivity over a year in certain patients.