The ultimate goal of root canal treatment is the elimination or reduction of microorganisms in the root canals of teeth. Microorganisms generally remain intact in the root canal part that is inaccessible after mechanical and chemical cleaning. In addition, Enterococcus faecalis with an incidence rate of 22-77% is known to be resistant to treatment and is the most common cause of root canal failure.1 E. faecalis can penetrate dentinal tubules, persist in high pH, and hunger-resistant, leading to secondary infections. 2.3
The use of a root canal sealer aims to reduce the residual microorganisms in the root canal due to its antibacterial effect.4 The most notable sealer is a zinc oxide-based sealer (Tg-sealer), a calcium hydroxide-based (Apexit) sealer, a glass ionomer (Ketac-endo) resin (AH26), silicone sealer (RoekoSeal), and pharmaceutical (Endometason) pharmaceutical sealer.5 In recent years, sealer containing trioxide aggregate minerals (MTA Fillapex) has also been introduced in dentistry.6 One of the important steps in root canal therapy is to choose an antibacterial sealer.
Ahangari, et al.7 evaluated the antibacterial activity of AH26, Dorifill, and Apexit on Peptostreptococcus microorganisms using agar diffusion test (ADT) in in vitro conditions. Based on these studies, both AH26 and Dorifill had higher antibacterial activity without significant differences, and Apexit showed the lowest antibacterial activity. 7
Morgental et al.6 evaluated the antibacterial activity of the sealer using direct contact (DCT) and agar diffusion test (ADT). ADT is used to evaluate the antibacterial activity of the non-toxic sealer (a soluble material), and DCT is used on an insoluble material (after the setting material). The results showed that in ADT, growth inhibition zones were seen only in Fillapex and Endofill MTAs. In ADT, Endometasone showed higher levels of antibacterial activity followed by AH-26, Tg-sealer. RoekoSeal sealer and Fillapex MTA showed no antibacterial activity. However, based on DCT, the Fillapex MTA sealer presents the highest antibacterial activity followed by AH-26, Tg-sealer, Endometason, RoekoSeal at 6 and 15 minutes; Tg-sealer, Endometason, AH-26, RoekoSeal after 60 minutes. This result shows that, different tests evaluate the properties of different antibacterial components.6
The ADT results show that the Endometason sealer has higher levels of antibacterial activity against E. faecalis. The reason for this can be attributed to the presence of components such as paraformaldehyde, thymol iodide, and zinc oxide in the structure of this sealer.8 AH-26 sealer ranks second in terms of antibacterial activity, which may be due to the release of paraformaldehyde from the sealer during the first 48 hours as well as the presence of antibacterial components on the epoxy resin, which remains within the sealer composition even after 2 weeks.5,9,10 The Tg-sealer, which ranks third in terms of antibacterial activity, is included as a zinc-based sealer (Zn). Its antibacterial activity may be due to the presence of zinc oxide and thymol iodide
Findings indicating that the RoekoSeal and MTA Fillapex seals do not exhibit inhibitory activity in E. Faecalis bacteria, can be attributed to the absence of appropriate medium capability and permeation of these sealers.11 This is consistent with the findings of the Yasuda et al.12 study, but unlike the results Morgental dkk.6 RoekoSeal and MTA Fillapex setting faster than other sealers. Therefore, it seems that setting time is one of the factors affecting the permeability of sealer and also its antibacterial activity.
RoekoSeal sealer showed the lowest antibacterial activity against E. faecalis. However, this sealer significantly prevented bacterial growth during observation compared with the control group. It can be concluded that this sealer at least does not cause bacterial growth in the medium.13
It should be noted that the sealer may provide different antibacterial activity in the newly mixed state and in a setting state (such as Fillapex MTA). It should be considered that in choosing sealers in addition to their antibacterial effects, biocompatibility is also important.