Evaluating the Influence of Access Cavity Design to Detect Additional Canals of Mandibular Premolars: An In Vitro...

The present in vitro study aimed to investigate the impact of three different access cavity types on the identification of the additional canals in mandibular premolars.

A total of 67 mandibular premolars were obtained, and periapical radiographs and CBCT scans were taken. Then, the access cavities were created in three stages: ultraconservative access cavity (UltraAC), conservative access cavity (CAC), and traditional access cavity (TAC). After completing each stage, the search for the second and third canals was conducted under a surgical microscope, using ultrasonic troughing. The differences between the three access cavity designs in identifying the second and third canals were compared using the chi-squared test. Additionally, the agreement between periapical radiographs, CBCT, and the operator in finding the canals was determined by measuring the kappa coefficient (p.value = 0.05).

62.68%, 34.32%, and 2.98% of the samples had one, two, and three root canals, respectively. The agreement between PA radiographs and CBCT images in identifying the number of canals was almost perfect (kappa: 0.968; p  < 0.001). Additionally, the agreement between the operator and initial PA radiographs and between the operator and CBCT in detecting the number of canals was substantial (kappa: 0.735 and 0.794, respectively; p  < 0.001). No difference was observed between the access cavity types in identifying the second and third canals. Of the two three-canal teeth, one was found in the TAC stage and the other in the CAC stage.

When the access cavity of mandibular premolars is prepared using magnification with a microscope and ultrasonic troughing, the design of the access cavity has no effect on identifying the additional canals in these teeth.

Mandibular premolars are reported to have more than one canal, and the effect of different access cavities has not been evaluated in canal detection of these teeth.