Mandibular second molar impaction. Part I: Genetic traits and characteristics.

Introduction: Detection of mandibular second molar (MM2) impaction is imperative for orthodontic diagnosis and treatment. In this study, we examined a possible genetic trait in MM2 impaction in 2 populations and defined distinctive characteristics.

Methods: Initial panoramic radiographs of patients of Israeli (n = 3500) and Chinese-American (n = 3000) origin, aged 11 to 15 years, were examined.