| Objective: Root canal disinfectant is one of the three research directions of root canal therapy. Although most of the bacteria, necrotized pulp and infected detin are removed from the root canals after chemical and mechanical preparation, there still have etiological agents such as residual bacteria, and endotoxin, in collateral pulp canals, deep part of dentinal tubules and periapex. Therefore, root canal disinfection is required to eliminate remaining bacteria that may survive inside root canals after complete chemical and mechanical preparation. At present, the medicine disinfection is most commonly used in the multitudinous root canal disinfection method. Actually, now there is no ideal root canal disinfectant. Cinnamaldehyde(CA) is an active compound of Cinnamon oil, which has several biologic activities such as anti-tumor, anti-platelet aggregation, and anti-mutagenic. Experimental study in vitro confirmed that CA had difference level of antibacterial action for 122 strains common anaerobian including 9 genera 22 species. Gram-Negative bacillus such as bacteroides melanogenicus were more sensitive to CA. CA has several biologic activities such as anti-fungus, anti-aerobia, volatility, and penetrability. The aim of this study was to provide experimental evidence for the exploitation of CA as a kind of root canal disinfectant through investigating the effect of CA on endotoxin in root canals and periapical periodontitis.Methods:This experimental model of periapical periodontitis was established with Wistar rats. 80 rats were divided randomly into 4 groups: group of formaldehyde cresol formocresol(FC)(25), group of CA(25), group of normalsodium(NS)(25), and the control group(5). After the model accomplished, the rats of the control group were sacrificed and the periapical tissues were observed by histopathology, as control to other three groups after sealing the drugs in the root canal. The rats of the former three groups were used in the measurement of root canal endotoxin and histopathological observation of periapical periodontitis.1. Measurement of root canal endotoxin: Anesthetized the rats, sterilized the teeth with 1% Iodine Tincture, dried, disclosed camera pulpi, put sterilizing paper point in camera pulpi and then put it in the glass centrifuge tube filled with 2ml NS, put the sample in refrigerator and deepfreeze, and placed FC, CA and NS in root canals after root canal preparation, and then sealed with glass-ionomer cement. The samples were took again from 5 rats of three groups on the 1st day, 3rd day, 7th day, 14th day and 21st day after the operation. The procedure was the same as above. The level of endotoxin was measured by quantitative chromogenic tachypleus amebocyte lysate method before and after sealing the drugs in the root canal.2. Histopathological observation of periapical tissue: The 5 rats from each of 3 groups were sacrificed on the 1st day, 3rd day, 7th day, 14th day and 21st day after sealing the drugs in the root canal, to harvest the jaw bone blocks including experiment teeth and periapical tissues. The jaw bone blocks were fixed for 24 hours with 10% Formaldehyde, decalcification for 30 days with EDTA, HE slides (4μm), observed by light microscope.Results:1. The measurement results of root canal endotoxin : There were significant difference before and after sealing the drugs in the root canal in the former two groups (P<0.05); There were no significant difference before and after sealing the drugs in the root canal in group of NS (P>0.05).There were no significant difference between group of FC and group of CA (P>0.05); there were significant difference between group of FC, group of CA and group of NS (P<0.05). Group of FC and group of CA: There were no significant difference between the 1st day and 3rd day after sealing the drugs in the root canal (P>0.05); There were no significant difference among 7th day, 14th day and 21st day after sealing the drugs in theroot canal(P>0.05); There were significant difference between 1st day , 3rd day and 7th day, 14th day ,21st day after sealing the drugs in the root canal(P <0.05).2. Histopathological observation of periapical tissue: There were no significant difference among the groups on the 1st day and 3rd day after sealing the drugs in the root canal (P> 0.05); There were significant difference between group of FC , group of CA and group of NS on the 7th day, 14th day and 21st day after sealing the drugs in the root canal (P<0.05), There were significant difference between group of FC , group of CA and the control group(P<0.05),There were no significant difference between group of FC and group of CA(P>0.05), There were no significant difference between group of NS and the control group(P>0.05).Conclusions:1. As root canal disinfectant, Cinnamaldehyde can decrease the level of endotoxin obviously, there were no significant difference between group of FC and group of CA.2. As root canal disinfectant, Cinnamaldehyde can relieve the periapical inflammation, there were no significant difference between group of FC and group of CA. |
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