| Background Endodontics and pariapical diseases are commondisease which affect oral and general health a lot with a high prevalencerate and a wide range of hazard. Root canal therapy is the preferredmethod for these diseases, aim to clean and shape the root canal by meansof instruments and chemical irrigation substances, in order to eliminate orreduce the amount of microorganisms and their by products, then giving acomplete tightly closed root canal filling, to forbid the pathogenic irritantsinfect pariapical tissues once more.An ideal orthograde or retrograde filling material should seal thepathways of communication between the root canal system and itssurrounding tissues. It should also be nontoxic, noncarcinogenic,nongenotoxic, biocompatible with the host tissues, insoluble in tissue fluids,dimensionally stable, easy to manipulate and be radiopaque for recognitionon radiographs. Mineral trioxide aggregate was developed andrecommended initially because existing root-end filling materials did nothave these “ideal†characteristics. MTA has also been recommended for pulp capping, pulpotomy, apical barrier formation in teeth with open apexes,repair of root perforations, and root canal filling.The price is the main factor to affect the promotion and application ofa new material. PC is a hot research for foreign scholars currently. Manystudies have demonstrated that both MTA and PC have the samecomposition and mechanism of action, and further more the price of PC ismuch more less expensive than MTA. This study attempted to explore thefeasibility of MTA be replaced by PC in clinical applications, as well as thenecessity of PC for further experiments in vitro.Objective A better sealing ability and antimicrobial activity oforthograde or retrograde root-end fillings plays a very important role toprotect the root canal therapy to maintain long-term good effect. Our studyaimed (1) To evaluate the sealing ability of PC, MTA, GIC and Am throughprotein leakage test.(2) To evaluate the antimicrobial activity of PC, MTAand GIC to the three microorganisms: Candida albicans, Escherichia coli,Streptococcus mutans, through the Agar diffusion method.(3) To comparethe cytotoxicity of PC and MTA on mouse embryos osteoblast cell by usinga colorimetric assay of tetrazolium reduction (XTT method).(4)To explorethe feasibility of MTA be replaced by PC in clinical applications, as well asthe necessity of PC for further experiments in vitro.Materials and Methods (1)Put all the sample teeth in the leakageassessment apparatus in an incubator at37℃. The water in the glass vial was changed24h a day and the BSA in the root canal was replenished12ha day during the continuous60d experiment. Coomassie Brilliant Bluetechnique was used to detect the protein permeated. Get the absorbancevalue of the permeated protein by722S visible range spectrophotometer,and the amount of protein leakage was calculated by the absorbance value.The less the protein leakage is, the better the sealing ability is, while themore the worse.(2) The sealers under study were handled according to themanufacturer’s instruction，all the sealers were handled with a diameter of5mm, and1mm thickness, then placed in the wells immediately after mixed,the wells contain1.5×108CFU/mL bacterial suspension of Candidaalbicans, Escherichia coli and Streptococcus mutans, respectively. After thesealers set, the agar plates were incubated at37℃for24-48h to allow themicroorganisms to grow and reagents to diffuse through the culturemedium. After incubation, the diameter of inhibition zones were measured.(3) The mouse embryos osteoblast cell(MC3T3-E1) was cultured in vitro,at37℃in an atmosphere containing5%CO2in air and100%relativehumidity. In this study5mg/ml,10mg/ml and30mg/ml of cement eluteswas configured as three different concentrations of PC and MTA,respectively. The cytotoxicity was evaluated by the method of XTT assay,the A value of each wells after72hours was detected, and the cell relativegrowth rate of every group was calculated according to the A value whilethe cytotoxic effect of each cement was evaluated. Results (1) During the experimental period of60d, the amount ofprotein leakage between group PC and group MTA had no significantdifference, the amount of protein leakage of group PC was much less thanthat of group GIC and group Am and achieve the significant difference, theamount of protein leakage of PC increased with time but has no significantstatistically difference.(2) There is no antimicrobial activity of all the threematerials was observed on Streptococcus mutans. There is no inhibitionzones was observed of GIC on the three test microorganisms. Theantimicrobial activity of PC is better than MTA against Candida albicans,and the same antibacterial activity of PC and MTA was found againstEscherichia coli.(3) The toxicity level of group PC was1and that of groupMTA was0when the concentration is5mg/ml, there was no significantstatistically differences between two groups; The same results was foundwhen the concentration is10mg/ml; The toxicity level of group PC was2and that of group MTA was4when the concentration was30mg/ml, therewas significant statistically differences between the two groups. The cellrelative growth rate reduced as the concentration increased in both groupPC and group MTA.Conclusions (1) Our study demonstrated that PC provides anobviously better seal than GIC and Am, the same seal as MTA when usedas apical barrier filling materials.(2) PC could effectively inhibit thegrowth of Candida albicans and Escherichia coli, we considered that PC has a certain antifungal and antibacterial properties.(3) The concentrationof5mg/ml and10mg/ml in both group PC and MTA could promote theproliferation of MC3T3-E1cells, and could be considered as the referenceconcentration of PC in the further experiments. There is different degree ofcytotoxic effect of PC and MTA in30mg/ml.(4) It is important to evaluatethe potential of PC in clinical practice and alternative to MTA, and thefurther experimental of physical-chemical properties, genotoxicity,mutagenicity, histocompatibility, animal study and pre-clinical study of PCused in this experiment are worth studying. |
