Tooth eruption symmetry in functional lateralities

Dental casts: and oral photographs from a cross-sectional sample of 2092 yo ung North Americans with detailed information on functional lateralities (e yedness, handedness and footedness) M ere examined to compare the proportio ns of symmetrical and asymmetrical eruption of the antimeric (left-right, c ontralateral pair) permanent teeth using a four-grade eruption scale. The p roportion of symmetrically erupting antimeric teeth was higher for some tee th in those with non-right-sidedness of the feet and eyes, but not signific antly so in the case of handedness. Left-footedness was significantly (95% confidence interval) associated with an increased proportion of symmetrical pairs of the maxillary first molar and mandibular lateral incisor, and non -right-eyedness with an increased proportion of symmetrical eruption and le ft/right non-balanced proportions of asymmetrical eruption in maxillary cen tral incisors. True right-sidedness (hand, foot and eye) was significantly (P less than or equal to 0.05) associated with advanced eruption of the lef t mandibular first molar. It is suggested that while the timing of antimeri c tooth emergence and clinical eruption is primarily programmed before crow n mineralization, starting approximately at the 30th gestational week in th e case of first permanent molars, symmetrical/asymmetrical tooth emergence and eruption may provide information a posteriori on prenatal and early pos tnatal growth and development. (C) 2001 Elsevier Science Ltd. All rights re served.