Influence of apical foramen lateral opening and file size on cemental canal instrumentation

Abstract

Since instrumentation of the apical foramen has been suggested for cleaning and disinfection of the cemental canal, selection of the file size and position of the apical foramen have challenging steps. This study analyzed the influence of apical foramen lateral opening and file size can exert on cemental canal instrumentation. Thirty-four human maxillary central incisors were divided in two groups: Group 1 (n=17), without flaring, and Group 2 (n=17), with flaring with LA Axxess burs. K-files of increasing diameters were progressively inserted into the canal until binding at the apical foramen was achieved and tips were visible and bonded with ethyl cyanoacrylate adhesive. Roots/files set were cross-sectioned 5 mm from the apex. Apices were examined by scanning electron microscopy at ×140 and digital images were captured. Data were analyzed statistically by Student's t test and Fisher's exact test at 5% significance level. SEM micrographs showed that 19 (56%) apical foramina emerged laterally to the root apex, whereas 15 (44%) coincided with it. Significantly more difficulty to reach the apical foramen was noted in Group 2. Results suggest that the larger the foraminal file size, the more difficult the apical foramen instrumentation may be in laterally emerged cemental canals.

Influence of the Cervical Enlargement in Determining the Diameter of the First File and Establishing the Working Length

“…Studies attest to the efficiency and safety of the files used for this phase of treatment with wide range of endodontic techniques that highlight the importance of this procedure prior to instrumentation of the apical region, in order to improve the quality of root canal preparation. [6][7][8][15][16][17] Associated with this, the correct determination of the length of work permits to establish with greater security, not only that the limit should be cleaning and shaping the canal, but also lets you choose the tool with which to start the preparation and how much will be needed enlarge it. Especially in cases of severe curvature teeth, there is more difficulty in apical preparation as a consequence of dentin at the entrance of the root canal.…”

“…Especially in cases of severe curvature teeth, there is more difficulty in apical preparation as a consequence of dentin at the entrance of the root canal. 8,17 These interferences represent an obstacle for the free access of the file in the apical portion, reflecting false sense of locking it. 13,18 The visualization of the tip of the file allowed the establishment of the working length of visual form when the indentation of 1 mm from the apical foramen.…”

“…These results are in agreement with those found by other authors. [6][7][8][15][16][17][19][20][21] The group using Gates-Glidden drills and stainless steel hand files had a higher increase in the diameter of the file when compared to the system ProTaper and K3. It is likely that the use of drills and hand tools promoted greater dilation of the cervical and middle thirds, an important factor for more precise adjustment of apical file.…”

“…The removal of any obstacles that may alter the course of files, prior to the onset of tooth length and apical modeling, it becomes imperative. [6][7][8] The extension of the cervical and medium third allows the file tip to work more lateral stress-free, providing instrumentation with respect to the original anatomy of the root canal steeper portion to the apical. 9 The determination of the actual diameter of the root canal anatomy allows to establish with greater security, the appropriate file to initiate and expand the apical preparation, providing removing contaminated dentin, favoring the treatment of periapical lesions.…”

Estudo longitudinal do sucesso clínico-radiográfico de dentes tratados com medicação intracanal de hidróxido de cálcio

“…A observação do diâmetro anatômico (inicial) e o respeito ao diâmetro cirúrgico (final) podem influenciar no resultado e contribuir para o sucesso dos tratamentos endodônticos 28,29 .…”