A quantitative evaluation of the distal displacement of the gingival zenith in the maxillary anterior teeth

The aim of this study was to quantify the specific distal displacement of the gingival zenith in the maxillary anterior dentition. Bilateral measurements, taken with a digital caliper in maxillary stone casts were recorded in six maxillary anterior teeth to evaluate distal displacement of the gingival zenith in relation to the long axis of the crowns. The gingival zenith was distally displaced between 0.45 and 1.01 mm in 90%, 85% and 60% of the central incisors, lateral incisors and canines, respectively. Contralateral comparisons between the tooth groups revealed significantly larger distal displacement of the zenith in left canine (p < 0.05). Ipsilateral comparisons revealed that the lateral displacement of the zenith was significantly larger in central than in lateral incisors (p < 0.05). Similarly, the zenith of lateral incisors was displaced significantly more distal than that of canine teeth (p < 0.05). Comparisons of the frequency of coincidence of the position of the gingival zenith with the long axis of the tooth revealed that it was significantly greater in canines than in lateral and central incisors (p < 0.05). The frequency and magnitude of distal displacement is tooth-dependent and larger in central than in lateral incisors, which in turn, is larger than in canines. These data could be used as reference points during esthetic anterior oral rehabilitation, especially in case of porcelain laminate veneers.