The antimicrobial activity of endodontic sealers can be important to the outcome of root canal treatment, but the amount of information on their antimicrobial abilities varies. To learn more, investigators evaluated four sealers using two in vitro testing methods.
They assessed the antimicrobial activity of four sealers -- Roeko GuttaFlow 2 (Coltene), AH Plus (Dentsply Maillefer), ProRoot MTA (Dentsply Sirona), and RealSeal (Kerr Endodontics) -- against Enterococcus faecalis, Escherichia coli, and Candida albicans using both the agar diffusion test and direct contact test. They found antimicrobial activity in three of the sealers, they reported in BMC Oral Health (June 18, 2019).
The antimicrobial abilities of endodontic sealers are useful in fighting off the residual microbes left in the root canal system that can cause inflammation, the study authors noted.
For the agar diffusion test, the researchers measured the diameter of the growth inhibition zone with both fresh and one-day-setting sealers. For the direct contact test, they exposed microorganisms in suspension to sealers for 10, 30, and 60 minutes and measured survival after mixing at one day and seven days.
The silicone sealer GuttaFlow 2 had no effect on the microorganisms tested (see table below). The product uses microsilver as its antimicrobial component, which has a larger size and smaller surface area than nanosilver (used in GuttaFlow), with the microsilver leaving a smaller number of atoms on the surface for biochemical reaction with microbes, according to the researchers.
| Mean zones of inhibition on agar diffusion test with various sealers | |||
| Sealer | E. faecalis | E. coli | C. albicans |
| Fresh GuttaFlow2 | 0 | 0 | 0 |
| Fresh AH Plus | 0 | 3.17 | 3 |
| Fresh RealSeal | 4.83 | 15.17 | 8 |
| Fresh ProRoot MTA | 0 | 0 | 3.5 |
| One-day GuttaFlow2 | 0 | 0 | 0 |
| One-day AH Plus | 0 | 0 | 0 |
| One-day RealSeal | 0 | 0 | 0 |
| One-day ProRoot MTA | 8 | 9.3 | 7.3 |
With the agar diffusion test, fresh RealSeal, a third-generation multimethacrylate resin-based material had the largest inhibition zone against the tested microbes. It was followed by epoxy resin-based AH Plus, the sealer gold standard, and calcium silicate-based ProRoot MTA, which was included in the study because it is a bioceramic cement to which new root-end filling materials are being compared. After setting for one day, ProRoot MTA showed inhibition zones against the three microbes, while the other sealers showed no inhibition activity.
For the direct contact test, fresh AH Plus demonstrated the strongest antimicrobial results against the tested microbes at all contact times, while fresh RealSeal and ProRoot MTA also showed strong antimicrobial results after one day of setting. RealSeal's antibacterial effects against E. faecalis remained after seven days.
"Freshly mixed AH Plus and RealSeal demonstrated strong antimicrobial effects," concluded the authors, led by Yuting Huang and Xiaoshuang Li of the department of stomatology at Union Hospital of Tongji Medical College at the Huazhong University of Science and Technology in Wuhan, China.
