# Antimicrobial and Antibiofilm Properties of Bioceramic Materials in Endodontics
## 4 Bioceramic Endodontic Sealers  
### Premixed Bioceramic Sealers  
Three premixed calcium silicate-based sealers with similar chemical composition have been developed, including iRoot SP (Innovative Bioceramics, Vancouver, BC, Canada), EndoSequence BC sealer (Brasseler USA, Savannah, GA, USA) and EndoSequence BC sealer HiFlow (Brasseler USA, Savannah, GA, USA) [57; 58]. Calcium silicates, calcium phosphate monobasic, zirconium oxide, tricalcium silicate, dicalcium silicate, and calcium hydroxide are the main components [10]. These three premixed sealers have shown biocompatibility, excellent sealing ability, and antimicrobial activity [59]. Bioceramic sealers have the advantage of prolonged antimicrobial activity [60]. Other types of sealers (e.g., epoxy resin-based sealers) can lose antimicrobial activity after setting [61]. A bioceramic sealer was reported to have long-lasting antimicrobial ability for up to 30 days due to the biomineralization process induced by calcium silicates/phosphrates from the sealer and from the dentin minerals [62]. Moisture from dentin promotes the hydration reaction to produce calcium silicate hydrogel and calcium hydroxide to elevate and maintain a high pH in the root canal environment [60]. Silica dissolved in a high pH environment may directly inhibit bacterial viability [63].  
Fresh iRoot SP was reported to have the highest pH value in the experimental periods among seven different sealers, and iRoot SP efficiently killed _E. faecalis_ using a direct contact test [60]. Confocal laser scanning microscopy also showed effective killing of _E. faecalis_ in dental tubules by freshly mixed EndoSequence BC sealer [64]. Another recent study showed that EndoSequence BC sealer exhibited significant antimicrobial capacity against an 8-week-old _E. faecalis_ biofilm in a dentin infection model [65]. In contrast, a previous study reported no antimicrobial effect from EndoSequence BC sealer to _E. faecalis_ under scanning electron microscopy [66]. The controversy from different studies may be due to the different methodologies applied. Scanning electron microscopy is a qualitative approach, which has limited field of view for the visualization of the overall biofilm growth on the substrate in high magnification [66]. The evaluation of the killing effect may then be limited to a small area when using SEM [66]. In contrast, confocal laser scanning microscopy with viability staining in the previous study allowed multiple areas of scanning on each sample in low magnification [64]. A more general assessment of the _E. faecalis_ biofilm killing effect could be applied [64]. Quantitative results could also be obtained from confocal data using three-dimensional reconstruction software. EndoSequence BC sealer was shown to have similar antibiofilm effect against _E. faecalis_ in a dentin infection model compared to AH-Plus sealer [62]. However, AH-Plus had higher antifungal activity than iRoot SP against _C. albicans_.  
Another premixed calcium silicate sealer, TotalFill BC (FKG Swiss Endo, La Chaux-de-Fonds, Switzerland), killed over 40% of _E. faecalis_ biofilm in dentin [67], and showed effective antimicrobial properties against single-species [68] and multi-species endodontic biofilm using a direct contact test [69; 70] and confocal laser scanning microscopy [71]. One recent study showed TotalFill BC had higher antimicrobial efficacy than AH-Plus sealer using a modified direct contact test [70].