Thursday, May 25, 2017

By: Board Certified Otolaryngologist – Head and Neck Surgeon

Every time a patient undergoes general anesthesia, there is risk to the teeth. General anesthesia involves intubation, a process where the anesthesiologist must manipulate the mouth to expose the vocal cords. Surgeries in or around the mouth carry additional risk of tooth injury. These surgeries include tonsillectomy, adenoidectomy, cleft palate, vocal cord surgery, and jaw (mandibular) fractures. 

Teeth are categorized as deciduous (baby) or permanent (adult) teeth. The first deciduous teeth, the central incisors, make their appearance between 6-12 months of age. In addition to their role in chewing, deciduous teeth provide spacing for permanent teeth. Injury to deciduous teeth may effect jaw development. Deciduous teeth are also required for proper speech development. Permanent teeth begin to erupt at age 6. A full set of permanent teeth is in place between 16 to 25 years of age. 

Dental injury in the operating room commonly results from forces required to open the mouth during intubation. A device called a laryngoscope is placed in the patient’s mouth to expose the vocal cords during intubation. To keep the mouth open during surgery of the oral cavity, retractors such as the Crowe-davis or digman are used. These retractors exert considerable force on a patient’s dentition. Preexisting dental decay may have weakened the teeth, increasing the chance for injury. Before intubation or operating in the mouth, the anesthesiologist and surgeon should be aware of any loose teeth. Rarely, as in trans-oral laryngeal tumor surgery, injury to the teeth may be unavoidable.

Diagnosis and Treatment Options

Tooth injury can be variable. Injury may consist of chipping a tooth, loosening a tooth, or avulsing a tooth. Previous restorative dental work can also be damaged. The upper jaw incisors are the most likely teeth to be injured. The upper jaw incisors are aesthetically important in smiling. Upper jaw incisors are critical to being able to bite foods such as apples.

Treatment of damaged teeth is case specific and can be expensive. Chipped teeth may require root canals in addition to cosmetic restoration. Nothing is as good as a natural tooth. No restoration lasts forever - an injured tooth in a 20-year old patient may need multiple restorative procedures during the patient’s lifetime. Restorative dental work can be color matched to the patient’s surrounding teeth, but it will not necessarily stay so with time. Coffee and other foods will stain dental ceramic differently from natural teeth. If long-term color match is desired, future procedures may be needed. In the case of avulsion, it may be possible for the tooth to be replanted. However, reimplantation of avulsed teeth is a technique and time sensitive procedure. If avulsed teeth are not restored, the jawbone will undergo bone loss over time. 

Documentation of dental injury should include pre and post injury dental records, dental x-rays, as well as pictures of the teeth and the patient’s smile.

Avoiding Dental Injury

Not all procedures require general anesthesia and intubation. Many procedures can be performed under sedation and local anesthesia. Thus intubation and the risk to teeth can be avoided. The patient may or may not have been offered the option to undergo local anesthesia. Because intubation - being placed on a breathing machine - is such a foreign sounding concept, the procedure of laryngoscopy and intubation may not always have been adequately discussed with the patient. 

For procedures requiring general anesthesia, several devices have been developed to minimize the risk of tooth injury. Dentasafe is a device that has been specifically designed to minimize the risk of chipping the incisors during intubation. Dentasafe consists of an adherent piece of foam that is attached to an anesthesiologist’s laryngoscope.

For surgeries in and around the mouth, dental guards can be used to reduce the risk of tooth injury. A dentist can fashion a custom dental guard before surgery. The patient may also fashion a dental guard using a commercially available “boil and bite” mouth guard. The surgeon can create a custom mouth guard from an Aquaplast splint, readily available in many operating rooms. In addition, most operating rooms have generic mouth guards that are used during laryngeal surgery. The University of Iowa Department of Otolaryngology has incorporated dental guards into a protocol for reducing dental injury during laryngoscopy. 

In conclusion, the dental risks can be overlooked when planning a procedure. Every time a patient is intubated for general anesthesia, the teeth are placed at risk. Surgeries in and around the mouth carry additional risks. Injuries to the teeth can require lifelong restorative treatments. Several devices to minimize dental injury have been developed.