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

Abstract

Objective: 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.

Methods and materials: 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).

Results: 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.

Conclusion: 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.

Clinical relevance: 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.