This study examined several methods used to estimate oral fissure position, lip margin position, and lip thickness recommended by Angel, George, Lebedinskaya, Taylor, Wilkinson et al., Balueva and Veselovskaya. A sample of 86 lateral head cephalograms of adult subjects from central Europe were measured and the actual and predicted dimensions were compared.
The best estimation for oral fissure position was "opposite the lower 3/4 mark of maxillary incisors" (error of 1.3 mm). Upper lip margin was predicted best by "upper 1/4 mark of maxillary incisors" (error of 1.7 mm), and lower lip margin by "cementum-enamel junction of mandibular incisors" (error of 2.3 mm).
The regression equations of Wilkinson et al. displayed least error (1.3 mm and 1.8 mm, respectively) for upper and lower lip thickness, and method of George (error of 3.4 mm) for total lip thickness.