Aim: This study aimed to evaluate the fracture resistance of tooth crowns endodontically irrigated using different protocols.

Materials and methods: A total of 76 bovine incisors were divided into four groups (n = 19): irrigation with distilled water (control; CON); conventional irrigation with positive apical pressure (PAP); passive ultrasonic irrigation using continuous flushing (PUI); and irrigation with PAP and heated sodium hypochlorite solution (PHS). The force required to fracture the crown was measured on a universal testing machine at an angle of 45°.

Results: The CON group had higher fracture resistance (351.71 ± 58.66 N) than the PAP and PUI groups (140.96 ± 37.26 N; 167.49 ± 40.08 N respectively). The PHS group had the lowest fracture resistance value (115.15 ± 41.07 N). Irrigation protocols had a significant effect on crown resistance (p < 0.01).

Conclusion: Teeth subjected to irrigation with heated sodium hypochlorite showed decreased resistance to crown fracture.

Clinical significance: The contact of the irrigating solution with the root canal walls potentially can cause their weakness, determining crown fracture.

Keywords: Endodontics, Root canal irrigants, Smear layer, Sodium hypochlorite, Tooth fracture.

How to cite this article: Baechtold M, da Cunha L, Souza E, Gabardo M, de Oliveira K, Baratto-Filho F, Leonardi D. Effect of Endodontic Irrigation Protocols on Crown Fracture Resistance. J Contemp Dent Pract 2018;19(7):768-772.

Source of support: Nil

Conflict of interest: None