Cases & Commentaries

Mark My Tooth

Commentary By Richard A. Smith, DDS

The Case

A 45-year-old healthy man was scheduled to have
two teeth extracted for progressive dental caries. The patient
underwent the extractions, awoke from the anesthesia, and then
realized that his upper left molars had been extracted instead of
his right. The error was recognized and acknowledged immediately
following the procedure. The patient still required extraction of
the diseased teeth, which occurred a few weeks later. He developed
no significant complication from either surgical procedure other
than enduring two rounds of anesthesia because of the error.

The Commentary

Wrong-site tooth extraction is both a significant
medical error and one of the major reasons for litigation against
oral and maxillofacial surgeons. This case illustrates a typical
scenario where a surgical extraction was performed on the incorrect
side. Through a root cause
analysis, we might find that the unfortunate event occurred as
a result of a cognitive error, the lack of a clear dental diagram
(Figure) with the correct teeth marked, an unclear
referral slip for the requested services, inadvertent reversal of
the radiographs posted on the light box, or disregard of the
Universal Protocol. Whatever its cause, once the error is
identified, the surgeon should disclose the error and arrange for
tooth replacement without any cost to the patient.

Prevalence of Wrong-Site Tooth

Despite anecdotal reports and known medico-legal
implications, few data exist about the prevalence of wrong-site
tooth extractions.(1,2)
However, most believe that, like other medical errors, these events
are under-reported.(3-5)
Common etiologies of wrong-site tooth extraction include cognitive
failure and miscommunication, multiple contiguous carious teeth
(rather than one identifiable diseased tooth), partially erupted
teeth mimicking third molars, teeth with gross decay that the
restorative dentist wants to save, reversed radiographs, and
nebulous tooth numbering systems.

Data from the Oral and Maxillofacial Surgeons
National Insurance Company (OMSNIC) Risk Retention Group (Rosemont,
Illinois) characterized the nature and extent of wrong-tooth or
wrong-site surgery performed by its 4300 members. In the database,
the most common reasons for filed claims were paresthesia from
third molar extractions and implant placement, infection, and
wrong-site tooth extraction. Wrong-site tooth extractions accounted
for 14% of all claims and 30% of the claims in which indemnity
payments were made. The company identified internal communication
problems in the surgeon's office and with the referring dentists as
the root causes for many wrong-site surgeries. They also reported
no pattern regarding sites and teeth involved in these claims and
that the surgeon's age and experience were not important predictors
of errors or safety. Unfortunately, no clear trends were identified
that would help reduce the number of wrong-site surgeries, and the
number of claims has stayed fairly constant despite risk management
seminars and online courses sponsored by OMSNIC.

Minimizing the Risk

Most cases of wrong-site tooth extraction can be
prevented by the development of an educational program, an
informative and unambiguous referral form, a preoperative
checklist, and incorporation of the Joint Commission's "Universal Protocol for Preventing Wrong Site, Wrong
Procedure, Wrong Person Surgery" into daily clinical

The following comprise the Universal

  • Preoperative verification process
    (correct patient, chart, x-ray, referral slip, dental diagram)
  • Marking the operative site
  • "Time out" immediately prior to
    beginning the procedure

The American Dental Association (ADA) has
supported national efforts to eliminate wrong-site surgery,
including wrong-site tooth extraction. However, many of the Joint
Commission's safeguards currently in place apply to practitioners
in hospitals and ambulatory surgery centers. Very few guidelines or
methods for prevention have been established for the primarily
office-based practitioners who routinely perform dental procedures.
For example, more than 70% of procedures, including dental
extractions and other dentoalveolar procedures, occur in this

Improving the safety of tooth extraction and
other types of dental surgery begins with a highly reliable
preparatory procedure. The process by which dentists and oral and
maxillofacial surgeons typically prepare patients for dental
extractions in the office setting involves the following steps:

  • Review the treatment plan (or if
    referred, the referral slip) regarding which tooth is to be
  • Review the medical history and record
    the vital signs.
  • Perform the oral evaluation to assess
    the surgical site.
  • Obtain written informed consent
    (generally, a pre-printed form with a notation of the tooth to be
  • Administer the local anesthesia with or
    without sedation or general anesthesia.
  • Perform the procedure.
  • Give postoperative instructions and
    dispense prescriptions as required.
  • Discharge patient when stable and
    arrange for follow-up.

Recommendations for Safe

In order to improve the quality of care provided
in dental offices and avoid dental errors, particularly wrong-site
tooth extraction, I would suggest that the following guidelines be

  • Develop an educational program for
    the entire staff on preventing wrong-site tooth extraction.
    Cognitive failure is the most frequent form of active failure in
    wrong-site tooth extractions, whereas communication and training
    represent latent
    factors contributing to these errors. A carefully designed
    staff education program may reduce the risk of cognitive
    Elements of an educational program include case-based materials,
    information feedback, and clinical guidelines.
  • Design a more informative referral
    slip without ambiguities. Any question or confusion about the
    correct tooth to be extracted should prompt a call to the referring
    dentist for clarification. The dentist should also be aware that
    missing teeth allow for drifting of the remaining teeth into an
    altered position and can add to potential
    confusion—particularly if different numbering systems are
    used to annotate teeth. The ADA recognizes two different tooth
    numbering systems. The dental practitioner should describe the
    tooth/teeth to be extracted in longhand (e.g., lower left first
    molar) on the referral slip and on the consent form, in order to be
    sure that both the health professionals and the patient understand
  • Inform the patient/parent/guardian
    verbally, and with a hand-held patient mirror, which tooth/teeth
    are to be extracted at the initial consultation
  • Confirm that the patient, chart, and
    x-ray (properly oriented) are correct and confirm which tooth is to
    be extracted at the surgical appointment. There is no practical
    or reliable way to mark teeth prior to the procedure. The Joint
    Commission and ADA have acknowledged alternatives such as marking
    the radiograph or a dental diagram visible to the surgeon. A
    "time-out" should be conducted to confirm the above using the
    two-person rule. The relationship between the dentist and the
    hygienist may determine whether the latter can comfortably disagree
    with the dentist without fear of retribution. The referral form
    should be checked prior to placing the dental elevator or forceps
    on the tooth. If there is prosthesis to be inserted after
    extraction (to replace the extracted tooth), the surgeon should
    verify that the prosthesis design is compatible with the extraction

Final Thoughts

If a wrong tooth is extracted, regardless of
whether the error was identified immediately or delayed, full
disclosure and possible remedies must be presented to the patient.
Any judgment or settlement that requires a dental licensee or their
insurer to pay damages in excess of $3000 because of negligence or
error in practice must be reported to the State Dental Board. The
Dental Boards also investigate any patient-generated

Take-Home Points

  • Incorporate the preoperative
    verification process into clinical practice (correct patient,
    chart, x-ray and its orientation, referral slip, and dental
  • Communicate directly with the referring
    dentist whenever clarification is required about the procedure
  • Use a "time out" immediately prior to
    beginning the procedure to verify patient, tooth, and procedure
    with the assistant at the time of extraction (two-person
  • Check the tooth position before and
    after application of the forceps.

Richard A. Smith, DDS
Clinical Professor Emeritus
University of California, San Francisco


1. Chang HH, Lee JJ, Cheng SJ, et al.
Effectiveness of an educational program in reducing the incidence
of wrong-site tooth extraction. Oral Surg Oral Med Oral Pathol Oral
Radiol Endod. 2004;98:288-294. [go to PubMed]

2. Jerrold L, Romeo M. The case of the wrong
tooth. Am J Orthod Dentofacial Orthop. 1991;100:376-384. [go to PubMed]

3. Canale ST. Wrong-site surgery: a preventable
complication. Clin Orthop Relat Res. 2005;433:26-29. [go to PubMed]

4. Brennan TA, Gawande A, Thomas E, et al.
Accidental deaths, saved lives, and improved quality. N Engl J Med.
2005;353:1405-1409. [go to PubMed]

5. Brennan TA, Leape LL, Laird NM, et al.
Incidence of adverse events and negligence in hospitalized
patients: results of the Harvard Medical Practice Study I. 1991.
Qual Saf Health Care. 2004;13:145-152. [go to PubMed]

6. Perrott DH, Yuen JP, Andresen RV, et al.
Office-based ambulatory anesthesia: outcomes of clinical practice
of oral and maxillofacial surgeons. J Oral Maxillofac Surg.
2003;61:983. Discussion 995. [go to PubMed]


Figure. Dental Diagram.

Click on thumbnail for larger view.