Examination of external apical root resorption with scanning electron microscopy

Accuracy of Root ZX II in Locating Foramen in Teeth with Apical Periodontitis: An In Vivo Study

“…The foramen on the root surface is an appropriate reference because it is easily visualized under the microscope (34,35), and a well-defined apical constriction is not expected in root canals of teeth with apical lesions (6,7,9). Moreover, it has been shown that the use of the Root ZX meter's reading of APEX gave more accurate measurements than the 0.5 bar reading (35,36).…”

“…The resorption of the hard tissues of the tooth might also occur during this process, resulting in loss of cementum and dentin (6). Apical root resorption can cause some enlargement of the apical canal diameter, deviation of the foramen, and partial or even complete distortion of the apical constriction (6)(7)(8).…”

“…The structural alterations in the root apex should be considered during endodontic treatment, especially when establishing the working length (6,8). Nevertheless, the resorption observed with the scanning electron microscope or in histologic studies is difficult to determine in clinical practice because radiographic assessment of small areas of resorption is complicated by several biological and technical factors (8)(9)(10).…”

Comparison of screw-in effect for several nickel-titanium rotary instruments in simulated resin root canal

“…Undoubtedly instrumentation beyond the apical foramen reduces the success rate. [8][9][10][11] Gutierrez et al 12) using scanning electron microscopy, found that overinstrumentation of root canals of human teeth provoked different types of apical cementum perforations and/or the production of zipping. By chance, many root canals can be inadvertently prepared beyond the apical foramen, which can be deleterious to the periapical tissues to heal in teeth with infected canal.…”

Influence of taper on the screw-in effect of nickel-titanium rotary files in simulated resin root canal

“…Undoubtedly instrumentation beyond the apical foramen reduces the success rate. 5,[12][13][14][15] Some kinds of factors have been investigated to be involved in the screw-in effect of Ni-Ti rotary files. Cross-sectional geometry, helical angles, pitch length and taper of files are included in these factors.…”