This retrospective study evaluated the effects of early extraction of immature lower third molar on preventing complications, particularly nerve injury following lower third molar removal. Patients were grouped according to age and radiographic results: group A (518 patients, ≤23 years, immature teeth with apical foramen not closed); group B (532 patients, >23 years, mature teeth with closed apical foramen). Group A included 230 males and 288 females (average age 17 years). In group A, 808 lower mandibular third molars were extracted bilaterally in 290 and unilaterally in 228 patients; the incidence of complications was 2.48% (20/808) (all were temporary), the incidence of nerve injury was 0%. Group B included 250 males and 282 females (average age 39 years). In group B, 810 lower third molars were extracted bilaterally in 278 and unilaterally in 254 patients; the incidence of complications was 10% (81/810), the incidence of nerve injury was 1.6% (13/810). All complications were temporary, except two removals of permanent inferior alveolar nerve numbness (>6 months). In this study, early removal of the lower third molar was effective in avoiding some postoperative complications, especially nerve injury. Early extraction of lower third molar in youngsters is recommended following a team consultation.
The lower third molar is the last tooth to develop, erupt, and mineralize in the permanent dentition. Clinically, lower third molars show the highest incidence of impaction and have been considered responsible for pathologies such as pericoronitis, periodontitis, second molar tooth-crown resorption, pain, cysts or odontogenic tumours, and primary or secondary crowding of the dentition. Anthropologically, jaws have become smaller in human evolution with unchanged tooth number and size. This leads to a disharmony of jaw and teeth, which contributes to a higher incidence of tooth impaction. In clinical dentistry, removal of impacted third molars is routine practice, but complications associated with the extraction include haemorrhage, secondary infection, alveolitis, mandible fracture, and nerve injury. There are different reasons for the complications and some preventive measures have been suggested by clinicians. Opinions vary about the early removal of these teeth to prevent the above-mentioned problems. This study compared the incidence of complications in two relatively large sample groups and obtained clinical justification for the early removal of third molar in defined circumstances. This may be a beneficial supplement to the world literature in this area.
Materials and methods
Patients presenting to the authors’ department from June 2006 to June 2010 were included in this study. The patients were grouped according to age and radiographic results: group A (≤23 years; immature teeth with the apical foramen not closed) and group B (>23 years; mature teeth with closed apical foramen). Medically compromised patients, pregnant women, patients with neurologic disturbances and other contraindications for removal (high blood pressure, diabetes, heart trouble, and uncontrolled systemic disease) were excluded. Clinical data were recorded, focusing on age, sex, and complications. Most group A patients were referred to the department of orthodontics and a team plan was agreed between the oral surgeons and orthodontists. Patients from the department of oral and maxillofacial surgery constituted a large portion of group B, while a small portion were transferred to the department of orthodontics. Panoramic radiographs were obtained and analysed before extraction in both groups. All the operations were performed in the same operating room, under local anaesthesia, by the same surgeons; surgical procedures and instruments were standardized. Oral antibiotics were administered to those with comparably longer surgical time and larger wounds. All patients were followed up 1 week after surgery at a return visit. If there were any patients who subjectively complained of any altered sensation in the areas innervated by the inferior alveolar nerve (IAN) or lingual nerves, further observation was conducted at 1, 2, and 3 weeks and during the first, third, and sixth months postoperatively.
The statistical analysis of the data was performed with SPSS 11.0 for Windows.
There were 1050 patients in this study. Group A included 518 patients (230 males; 288 females), aged 10–23 years (average 17 years) ( Figs. 1 and 2 ). 808 lower third molars were extracted, including bilateral removal in 290 patients and unilateral removal in 228. There were 532 patients in group B (250 males; 282 females), aged 24–59 years (average 39 years) ( Figs. 1 and 2 ). 810 lower third molars were extracted, including bilateral removal in 278 patients and unilateral removal in 254. In group A the overall incidence of complications was 2.48% (20/808), the incidence of nerve injury was 0%, all complications were temporary ( Fig. 3 ). In group B, the overall incidence of complications was 10% (81/810), the incidence of nerve injury is 1.6% (13/810). All complications were temporary, except two cases of permanent IAN numbness (>6 months).
There were statistically significant differences between both groups regarding complications ( Table 1 ).