Pepper T, Grimshaw P, Konarzewski T, Combes J
Defence Medical Services, Whittington Barracks, Lichfield, Staffordshire, WS14 9PY.
Br J Oral Maxillofac Surg. 2017 Feb;55(2):160-163. doi: 10.1016/j.bjoms.2016.10.009. Epub 2016 Nov 15.
Mandibular third molars are commonly removed because of distal caries in the adjacent tooth. To find out the prevalence of distal caries in mandibular second molars we retrospectively studied the primary care dental records of 720 British military personnel (653 men and 67 women) from various centres. These records are standardised and personnel are required to attend for inspection regularly. Those who had been under 20 years of age at enlistment, who had served for at least five years, and had five recorded dental inspections, were included. The median (IQR) period from the first to last inspection was 15 (9.7 - 19.2) years, and inspections were a median (IQR) of 14.1 (12.8 - 15.8) months apart. A total of 59/1414 (4.2%) mandibular second molars developed caries in their distal surfaces. This was 4% higher when they were associated with a partially-erupted mandibular third molar than when associated with one that was fully erupted or absent (29/414 (7%) compared with 30/1000 (3%); p=0.001). Carious lesions developed in the distal aspect of 22/133 mandibular second molars (16.5%) that were adjacent to a mesioangularly impacted third molar. Of these, 19/22 were successfully restored. Four mesioangularly impacted mandibular third molars would have to be extracted to prevent one case of distal caries in a second molar (number needed to treat=3.25). Second molars that are associated with a partially-erupted mesioangular mandibular third molar have a higher risk of caries, and this can be reduced by removal of the third molar. However, distal caries in second molars seems to be a treatable and slowly-developing phenomenon and we recommend that the merits and risks of the prophylactic removal of third molars should be discussed with the patient, who should have long-term clinical and radiographic checks if the tooth is retained.
下颌第三磨牙通常因邻牙远中龋而被拔除。为了了解下颌第二磨牙远中龋的患病率，我们回顾性研究了来自不同中心的720名英国军事人员（653名男性和67名女性）的初级保健牙科记录。这些记录是标准化的，并且要求人员定期参加检查。纳入标准为入伍时年龄在20岁以下、服役至少五年且有五次记录在案的牙科检查的人员。从第一次检查到最后一次检查的中位（四分位间距）时间为15（9.7 - 19.2）年，检查间隔的中位（四分位间距）时间为14.1（12.8 - 15.8）个月。在1414颗下颌第二磨牙中，共有59颗（4.2%）远中面发生龋坏。当与部分萌出的下颌第三磨牙相关时，其远中龋患病率比与完全萌出或缺失的第三磨牙相关时高4%（29/414（7%）对比30/1000（3%）；p = 0.001）。在与近中倾斜阻生第三磨牙相邻的133颗下颌第二磨牙中，有22颗（16.5%）远中面出现龋损。其中，19/22成功修复。为预防一例下颌第二磨牙远中龋，需要拔除四颗近中倾斜阻生下颌第三磨牙（治疗所需数量 = 3.25）。与部分萌出的近中倾斜下颌第三磨牙相关的第二磨牙患龋风险更高，拔除第三磨牙可降低这种风险。然而，第二磨牙远中龋似乎是一种可治疗且发展缓慢的现象，我们建议应与患者讨论预防性拔除第三磨牙的利弊，如果保留该牙，患者应进行长期临床和影像学检查。
