Complications of a dental inlay or onlay are uncommon, but any procedure involves risks and the potential complications that may become serious in some cases. Complications can develop during the procedure or your recovery. Risks and potential complications of a dental inlay or onlay include: Allergic reaction to the inlay or onlay Anesthetic complications, such as allergic reaction and nerve or blood vessel injury Expansion and shrinkage of a composite inlay or onlay, which can which can damage the inlay or onlay and the tooth Decay in the tooth if the seal of the onlay or inlay is lost or damaged Injury to the mouth or gums Sensitivity to heat and cold in the affected tooth. This can occur when an inlay or onlay is lost or damaged and exposes tooth structure and nerve endings. Reducing your risk of complications You can reduce the risk of certain complications by: Following activity, dietary and lifestyle restrictions and recommendations before your inlay or onlay procedure and during recovery Informing your dentist if you are nursing or if there is any possibility that you may be pregnant Notifying your dentist immediately of any concerns after the procedure such as pain, fever, and difficulty chewing Taking your medications exactly as directed Telling all members of your care team if you have any allergies, especially any metal allergies if your dentist is using a metal inlay or onlay