To the Editor:—

Damage to the teeth can occur during general anesthesia1and is a common cause of claims against anesthesiologists.2,3A detailed knowledge of the preanesthesia dental status provides a reliable way to distinguish valid from fraudulent (and often expensive) claims of injury. Here we present a simple system for performing and documenting a dental examination.

In North America, the standard convention for numbering teeth starts with No. 1 as the right upper wisdom tooth, proceeds around the maxillary arch to No. 16, drops to the wisdom tooth immediately below (No. 17), and thence proceeds around the mandibular arch to the lower right wisdom tooth (No. 32). The numbers are assigned to specific teeth, so a missing tooth is counted even though it is not there.

The anterior teeth are of most interest to an anesthesiologist because these are most likely to be damaged during intubation, or if a partially anesthetized patient should bite down hard on a rigid airway.3A simplified charting system for these teeth is shown in figure 1. The right upper canine (No. 6) is easy to identify. It and the left upper canine (No. 11) bracket two central incisors, Nos. 8 and 9 (the “Bugs Bunny” teeth) and two smaller lateral incisors on each side (Nos. 7 and 10). The trick to the numbering system is realizing the correspondence between upper and lower teeth. The left lower canine is No. 22 (remember: “11 times 2 equals 22”), and normal teeth are symmetric around to the right lower canine (No. 27).

Fig. 1. Easy tooth-numbering guide based on the concept that “11 times 2 equals 22.” 

Fig. 1. Easy tooth-numbering guide based on the concept that “11 times 2 equals 22.” 

Our typical documentation of a preexisting dental condition contains comments such as “missing No. 6, and chipped No. 23.” The presence of caps, crowns, bridges, and loose teeth should also be noted with the relevant tooth number. A drawing of a specific tooth is an additional way to indicate the degree of damage. On occasion, only a few teeth will be present, and the absence of reference teeth may make it difficult to determine which number or numbers apply. A simple description of the remaining teeth and their locations will suffice in this situation.

A clear record of preexisting dental problems provides a firm basis for assessing claims of dental injury during anesthesia.

*University of Pittsburgh, Pittsburgh,


Warner ME, Benenfeld SM, Warner MA, Schroeder DR, Maxson PM: Perianesthetic dental injuries: Frequency, outcomes, and risk factors. Anesthesiology 1999; 90:1302–5
Chadwick RG, Lindsay SM: Dental injuries during general anaesthesia. Br Dent J 1996; 180:255–8
Givol N, Gershtansky Y, Halamish-Shani T, Taicher S, Perel A, Segal E: Perianesthetic dental injuries: Analysis of incident reports. J Clin Anesth 2004; 16:173–6