Background: The aim of this study was to analyse the number of root canals in maxillary first premolars, first molars and mandibular first molar teeth from an 18 th to 19 th century Radom (Poland) population, and then assess whether the diversity of root canals has fluctuated for about two hundred years. Materials and methods: A total of 139 human permanent teeth were analysed by cone beam computed tomography in three projections. The types of root canal systems were classified in each tooth root separately. Results: In one-rooted maxillary premolars, two canals occurred most often (53%). In two-rooted majority buccal (91%) and every palatal roots there is one canal. All three-rooted maxillary premolars have one root canal. In two-rooted first maxillary molars, fused roots have two canals. All mesiobuccal roots presented type 2-1 canal configurations. In three-rooted maxillary first molars in the mesiobuccal roots the most common root canal type is 2-1 (72%). A second mesiobuccal canal occurred in 86%. The distobuccal and palatal roots presented one canal in all cases. First mandibular molars occurred in two-rooted form in 98%. In mesial roots, two root canals predominated (59%). Most distal root (66%) had one canal. In three-rooted teeth one root canal was the most frequent finding. Conclusions: Knowledge about the variation in root canals is important in studies of past populations. This evidence may be important in relation to assessing the variability of human populations. The analysis carried out show the cohesion between the historical population of Radom and other groups from modern Poland.

Root resorption in moved teeth is a common undesirable side effect of orthodontic treatment. This pathology usually affects permanent teeth. Although any part of the root may be involved, the apical or cervical area is usually affected. The formation and development of these changes are a long-term process and depend on various factors. The etiology of resorptive changes associated with orthodontic treatment has been widely discussed by many authors, who proposed numerous classifications. Particularly noteworthy are the works on techniques for the treatment of malocclusion and their potential adverse effects. Modern diagnostic methods allow for an early detection of this pathology and the implementation of appropriate therapeutic measures. These techniques include periapical radiography (paralleling technique) combined with cone-beam computed tomography. Dentists not only notice the need to achieve a beautiful smile, but they also take into account possible root shortening. This process is not fully understood, but realizing its existence is important for planning and implementing both orthodontic and general dental treatment.