Cytotoxicity, interaction with dentine and efficacy on multispecies biofilms of a modified salt solution intended for endodontic disinfection in a new in vitro biofilm model.
OBJECTIVE
To investigate the cytotoxicity of a modified salt solution (MSS) and evaluate the antimicrobial properties of MSS on in vitro biofilm models.


METHODS
In a metabolic assay, fibroblasts derived from periodontal ligaments (PDL) of human extracted teeth were cultured and challenged with MSS or controls. Then, in active attachment biofilm models, the efficacy of MSS in the presence of dentine powder and in eliminating mature biofilms was investigated. In the dentine assay, a biofilm of Enterococcus faecalis was employed. For the final assay, microorganisms were retrieved from infected root canals and cultured to produce biofilms. After the treatments with MSS or the controls, the biofilms were collected, serially diluted and plated. The colony-forming units were counted. One-way anova was used to analyse the differences between the groups. A P < 0.05 was considered significant.


RESULTS
The PDL fibroblasts remained metabolically active after challenges with MSS. Dentine powder did not alter the efficacy of MSS (P > 0.05). In endodontic biofilms, the culturable bacteria were equally reduced by MSS, 2% chlorhexidine (CHX) or 2% sodium hypochlorite (NaOCl) (P > 0.05).


CONCLUSIONS
Modified salt solution is noncytotoxic in vitro and has good antimicrobial properties equal to CHX and NaOCl. Although the results are promising, ex vivo and in vivo studies are needed before its use as an interappointment root canal dressing can be considered.
Department of Preventive Dentistry, Academic Centre for Dentistry, Amsterdam, the Netherlands; Department of Cariology, Endodontology and Pedodontology, Academic Centre for Dentistry, Amsterdam, the Netherlands.
S V
SV
van der Waal
N
N
Scheres
J J
JJ
de Soet
P R
PR
Wesselink
W
W
Crielaard
D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D002478:Cells, Cultured; D002710:Chlorhexidine / Q000494:pharmacology; D015169:Colony Count, Microbial; D003786:Dental Pulp Cavity / Q000187:drug effects* / Q000382:microbiology*; D003804:Dentin / Q000187:drug effects*; D004203:Disinfection / Q000379:methods*; D013293:Enterococcus faecalis; D005347:Fibroblasts; D006801:Humans; D066298:In Vitro Techniques; D012388:Root Canal Irrigants / Q000494:pharmacology*; D012973:Sodium Hypochlorite / Q000494:pharmacology; D012996:Solutions; D013778:Tetrazolium Salts / Q000494:pharmacology*
C110656:2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium; D000891:Anti-Infective Agents, Local; D012388:Root Canal Irrigants; D012996:Solutions; D013778:Tetrazolium Salts; D012973:Sodium Hypochlorite; D002710:Chlorhexidine
biofilm; cytotoxicity; disinfection; endodontic; modified salt solution; potassium sorbate