Aim

The main aim of the study was to evaluate tooth position in plaster models of nonorthodontic subjects that have optimal occlusion, using the American Board of Orthodontics (ABO) criteria and comparing it to ABO standards.

Methods

Forty nonorthodontic subjects with optimal occlusion were evaluated for teeth positioning with ABO measurement criteria, using the ABO gauge. These measurements were compared to the ABO standards. On the panoramic radiographs of these subjects, distances between the roots of teeth were measured using the digital ruler in Quick Ceph^R. Lateral cephalograms were scanned and digitized into Quick Ceph^R systems to evaluate the skeletal anteroposterior and vertical relationship. Means and standard deviations were calculated for all the variables and compared to ABO standards. Correlations were obtained between attrition and overjet. Correlations were also studied between anteroposterior skeletal relation, vertical skeletal relation, and teeth positioning. In subjects that had accurate age records, the relationship between age and change in buccolingual inclination was evaluated.

Results

A significant difference in the mean values for inclination of maxillary and mandibular first bicuspids, second bicuspids, first molars, and second molars as compared to the board criteria was observed. Accuracy of panoramic radiograph to measure root proximity, especially in the cuspid region, is questionable. There was a positive correlation between overjet at the cuspid region and attrition. There was a minimal correlation between age and buccolingual inclination of teeth, indicating only a trend for mandibular second bicuspid to upright with age.

Conclusion

The ABO criteria and standards used to evaluate finished orthodontic cases are consistent with naturally occurring optimal dentitions, except for buccolingual inclination of posterior teeth in both maxillary and mandibular arches.

Search results

Natural Versus Board Standards: Similarity or Differences? Evaluation of Plaster Models of Nonorthodontic Optimal Occlusion Using ABO Criteria