Frequency of Root Curvatures in Molars – an in Vitro Study

Root canal curvatures are often the main reason for a poor root canal treatment. The clinical x-ray images often do not give a precise view of the degree of the root curvature from the axial axis. The aim of the present study was to measure the severe curvatures > 25o separately for upper and lower jaw in representative number of extracted human molars. The length of each root was measured from the respective cusp for all 771 roots. All deviations were measured in the apical half of the roots, and registered when higher then 25-30o. The data shows that 47 of 461 upper teeth (10%) and 49 of 312 lower teeth (15.7%) were with severe curvatures. The highest numbers were found in lower third molars – 19.2%. In Bulgaria, root lengths are lower, than in the commonly used tables. This two ndings are proving the higher risk of iatrogenic mistakes during root canal treatment. We found diagnostic x-rays and a working hypothesis for curvatures of each root after the rst half essential.