Evaluation of statistics and desirable experimental design of a histomorphometrical method for studies of root resorption

This study characterizes how the accuracy and precision of estimates of the true extent of root resorption are influenced when measuring serial‐sectioned individual teeth; different types of teeth with different degrees of resorption, sampling different numbers of sections and registration points. Maxillary and mandibular central and lateral incisors can be used for studies of root resorption with this method. Eight points of registration were required for every section when smaller differences in the means of root resorption between experimental groups were expected. When comparing groups with extensive differences, 4 points of registration were enough. The points should be labial, lingual, mesial and distal. Ten to 17 sections per tooth seemed to be sufficient in most instances. The number of experimental animals needed depended on the statistical procedures and expected outcome of the experiment.