Accumulating Wisdom on Third Molar Extraction

Extraction of third molars—“wisdom teeth”—is one of the most common operations performed in the United States. For this reason, small changes in practice resulting in improved outcomes translate into large benefits across the population.

The Center for Applied Clinical Investigation (CACI) maintains an active portfolio of clinical research endeavors committed to advancing the conventional wisdom on third molar surgery. “With the emergence of non-invasive diagnostic tools and engineered materials, we are in a position to broaden the skill set of the oral and maxillofacial surgeon,” explains Dr. Dodson. “It is no longer necessary to leave painful and serious side effects to chance.”

CACI’s research agenda includes an in-depth look at factors that predict and prevent adverse outcomes following third molar extraction. “Given the huge volume of cases, and the fact that most patients are otherwise healthy, third molar extraction samples present a rich clinical research database,” says Dr. Dodson.

Predicting Difficult Extractions

With third molar extractions dominating the case mix of most oral and maxillofacial surgery practices it is easy to become standardized in planning for these procedures. But as most oral and maxillofacial surgeons know, many ‘routine’ cases take an unexpected course once the procedure begins. “We’ve been able to identify a number of anatomic and situational factors that contribute statistically to the time of the procedure and the patient’s return to functional status,” says Dr. Dodson. “Providing evidence-based guidelines help oral and maxillofacial surgeons to set more realistic expectations for the patient and to plan resources within the clinic.”

Preventing Nerve Injuries

Nerve injury resulting in numbness to the lip is a serious, though uncommon (<1%), adverse outcome from third molar surgery. Most oral and maxillofacial surgeons obtain panoramic radiographs to evaluate patients pre-operatively. This common diagnostic tool was also found to be useful in predicting which patients would have increased risk for developing nerve injury from third molar extraction. Using this information, high risk patients could be examined subsequently using CT scans to identify those who are likely to experience nerve injury from third molar extraction. “While it is impractical to obtain CT images prior to all third molar extractions,” explains Dr. Dodson, “we’ve been able to develop a model that uses these two technologies optimally to decrease the risk of a serious adverse outcome.”

Socket Wound Healing

A very specific group of third molar extraction patients have an increased risk of developing wound healing complications postoperatively. Defined as age greater than twenty-five, with horizontal or mesio-angular impaction and underlying evidence of active periodontal disease, these patients are shown to be at higher risk statistically for experiencing extraction site complications. “For patients who fall within these parameters,” Dr. Dodson says, “we recommend reconstructing the extraction site with demineralized bone matrix to achieve a higher likelihood of a satisfactory outcome.”

Other Adverse Outcomes

CACI is actively involved in a collaborative multi-center research project to estimate the frequency of, and to identify factors associated with adverse outcomes from third molar extractions. Sponsored by AAOMS, this project is the largest prospective cohort study ever undertaken to evaluate outcomes following third molar extraction. “Preliminary evidence suggests that age may be an important determinant of outcome in third molar surgery,” explains Dr. Dodson, who is co-principal investigator on this study. “We aim to develop a model that establishes standards of practice for third molar removal that minimize the risk of complications.”

Bibliography

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Susarla SM, Dodson TB. Estimating Third Molar Extraction Difficulty: Subjective and Objective Factors. J Oral and Maxillofac Surg 63: 427-34, 2005.

Sedaghatfar M, August MA, Dodson TB. Panoramic radiographic findings as predictors of inferior alveolar nerve exposure following third molar extractions. J Oral Maxillofac Surg 63:3-7, 2005.

Dodson TB. Is there a role for reconstructive techniques to prevent periodontal defects after third molar surgery. J Oral Maxillfac Surg. 63:891:2005
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Dodson TB. Strategies for managing anticoagulated patients requiring dental extractions: An exercise in evidenced-based clinical practice. J Massachusetts Dental Society 50:44, 2002

Lee JT, Dodson TB. The effect of mandibular third molar presence and position on the risk of an angle fracture. J Oral Maxillofac Surg 58:394, 2000.

Dodson TB. Prediction of post extraction complications in HIV-positive patients. Oral Surg Oral Med Oral Pathol 84: 474-9, 1997.

Dodson TB. Demineralized bone grafts to reconstruct third molar extraction site defects. Oral Surg Oral Med Oral Pathol, 82: 241-247, 1996.

“Technology and evidence-based practice continue to evolve our understanding of how best to perform this most common of surgical procedures.”