Relationship between the Apical Preparation Diameter and the Apical Seal: An In Vitro Study

Objectives The aim of the study is to define the relationship between the apical preparation diameter and the apical sealing ability to highlight the importance of the preservation of the diameter and the original position of the apical foramen. Materials and Methods 50 extracted maxillary incisors were randomly allocated into three groups of 15 teeth each (n = 15) according to the apical preparation size: Group 1: finishing file F1 corresponding to size 20 reached the working length (ProTaper Universal system Dentsply®); Group 2: prepared up to size 30 corresponding to finishing file F30; Group 3: prepared up to size 50 corresponding to finishing file F5. Five teeth were assigned to positive and negative control groups. After the filling of the root canals, the teeth were isolated and immersed in a dye solution, then cut longitudinally, photographed, and the dye penetration were calculated using a computer software. Results Comparison of the three different apical preparation sizes showed no statistically significant differences regarding the apical microleakage. Conclusion The most important value of the dye penetration was observed in the group with the largest apical diameter.