Does mandibular third molar have an impact on dental mandibular anterior crowding? A literature review

Mandibular dental anterior crowding is a common multi-factorial phenomenon. The involvement of the lower third molar remains unclear. These pending questions led us to conduct a literature review to evaluate the impact of the lower third molar on mandibular dental anterior crowding. Twelve articles were selected, published from 1974 to 2014. Four studies were prospective. Sample size ranged from 30 to 9044. The average age was 20.56 years old. Seven studies considered patient with orthodontic treatment. The studies compared two to four groups. Studying tools were radiographs, casts and clinical examinations. Little's irregularity index, TSALD and Ganss ratio were used. In total, 83% of articles (n = 10/12) did not find any significant relationship between lower third molar and mandibular dental anterior crowding. However, methods and designs of these studies being questionable, a definite conclusion on the impact of mandibular third molar on mandibular dental anterior crowding cannot be set.