Influence of Length of Root Canal Obturation on Apical Periodontitis Detected by Periapical Radiography and Cone Beam Computed Tomography

By Moura MS, Guedes OA, De Alencar AH, Azevedo BC, Estrela C.

Date: 05/2010
Journal: JOE


•Purpose:  evaluate the influence of root canal obturation (RCO) length on AP detected by periapical radiographs or CBCT images.

•N=  503 RCOs in 300 teeth.


  • A total of 503 root canal obturations were evaluated by using periapical radiography and CBCT.
  • All patients with history of endodontic treatment and with or without AP detected
  • Teeth were distributed into 3 groups: (G1) anterior teeth (G2) premolars  (G3) molars .
  • PA radiographs and CBCT were taken.
  • Images were examined from the radiographic apex to the tip of the filling material and classified as almost 2 mm, 1mm short or beyond apex, or at the apex.
  • RCO length at the apex was compared with AP in both imaging methods.

•Most highlighted Results: 

1.AP was detected at all lengths of root canal obturation in PA or CBCT views.

2.With periapical radiographs, AP was detected 4 times more often in molars when RCO extended to a point close to the radiographic apex, but when CBCT was used, the detection of AP in RCO that extended 1 mm beyond the apex was 16 times greater.

  • AP was more frequently detected when CBCT images were used.
  • AP was significantly more frequent in molars than other teeth, regardless of diagnostic method.

Clinical significance:

AP was detected in all groups of obturation lengths, regardless of imaging method, which suggested that obturation length might not be associated with AP when the root canal was not perfectly cleaned, shaped, and 3-D filled with a good coronal restoration.