Q: My son had his two canines removed for orthodontic purposes. When the dentist attempted to pull these two teeth, they had 3 roots each. Can you tell me why this is so and is this unusual? Does this coincide with other health issues?

A:Dental traits ordinarily exhibit a high degree of symmetry but two types of asymmetry are commonly seen - directional asymmetry (traits that show a distinct right or left side bias) and fluctuating asymmetry (random and show no consistent bias within a population). The occurrence of an extra crown is a normal dental developmental anomaly of no clinical significance.