摘要：Objectives. We investigated outcomes of third molar removal or retention in adolescents and young adults. Methods. We recruited patients aged 16 to 22 years from a dental practice–based research network in the Pacific Northwest from May 2009 through September 2010 who had at least 1 third molar present and had never undergone third molar removal. Data were acquired via questionnaire and clinical examination at baseline, periodic online questionnaires, and clinical examination at 24 months. Results. A total of 801 patients participated. Among patients undergoing third molar removal, rates of paresthesia and jaw joint symptoms lasting more than 1 month were 6.3 and 34.3 per 100 person-years, respectively. Among patients not undergoing removal, corresponding rates were 0.7 and 8.8. Periodontal attachment loss at distal sites of second molars did not significantly differ by third molar removal status. Incident caries at the distal surfaces of second molars occurred in fewer than 1% of all sites. Conclusions. Rates of paresthesia and temporomandibular joint disorder were higher after third molar removal. Periodontal attachment loss and incident caries at the distal sites of second molars were not affected by extraction status. Third molar removal is one of the most common dental surgical procedures in the United States, representing 95% of all extractions among patients aged 16 to 21 years in an insured population. 1 Although the risks associated with third molar removal are generally minor, such as pain and swelling, some complications may be more serious, such as injury to the temporomandibular joint (TMJ) or permanent paresthesia. Because many third molars are surgically removed, the costs associated with this procedure can be significant. One report estimated that more than $3 billion is spent annually in the United States for third molar removal. 2 Because decisions regarding removal or retention of third molars are often made in late adolescence and early adulthood, understanding the risks and benefits of removal or retention during this time period is important. The prophylactic removal of asymptomatic third molars has been the subject of considerable controversy. On one hand, some have advocated early removal of third molars as beneficial to patients to prevent the risk of future pathology and to minimize operative and postoperative risks. 3–6 Another common argument for third molar removal is prevention of crowding of lower incisors. In the past decade, prevention of periodontal pathology has been proposed as a reason to prophylactically remove third molars. 7,8 This theory suggests that periodontal pathology initiates in third molars and is more likely to proceed when third molars are retained. Additionally, if left unaddressed, the periodontal pathology may lead to negative cardiovascular, obstetric, metabolic, and renal health outcomes. 9 On the other hand, third molar removal can result in various types of morbidity, such as pain, swelling, bleeding, infection, dry socket, trismus, paresthesia, and temporomandibular joint disorder (TMD). 8 Most of these complications resolve, but some, such as paresthesia or TMD, may persist and become chronic or permanent conditions. The overall rate of complications from third molar removal varies considerably, with values reported from 4.6% 10 to 21%. 4 Thus, some feel that monitoring asymptomatic third molars is the appropriate strategy. 11–13 In fact, the American Public Health Association and the United Kingdom’s National Health Service currently recommend against the removal of asymptomatic third molars. 14,15 Nevertheless, about 50% of insured individuals in the United States will have their third molars removed by the time they are 20. 16 Many studies have reported on the short-term complications of third molar removal, but few have compared outcomes for patients who do and do not elect to have third molars removed for an intermediate period of time (≤ 2 years). Therefore, we investigated the sequela of third molar removal or retention over a 2-year period. This time frame allowed the identification of sequela that were becoming persistent or chronic after third molar removal, as well as the assessment of conditions related to retained third molars during a period when they are erupting. Our specific aims were to compare the rates of paresthesia, TMD, and caries, as well as periodontal attachment loss. A companion article reports on general dentists’ recommendations for retention or removal of third molars and patient compliance with the recommendations. 17
