| Population aging has become the important issues of social concern, followed by the health problems of the elderly. Due to tooth wear, gingival recession to expose teeth, environment changing of oral hygiene and a series of factors, the incidence of root caries increased significantly in elderly. Although antibiotics, fluoride and other drugs has achieved some results in the prevention of dental caries, the toxic side effects can not be ignored. So the development of new drugs against dental caries has been the focus of domestic and foreign scholars. The tea polyphenols, as active ingredient of antibacterial in the tea, accounting for 25% of the dry weight of tea, is an efficient and low toxicity free radical scavengers of antioxidants. It can not only improve human immunity, slow aging, lower blood pressure, blood lipids, but also a strong inhibitory effect on the growth of Streptococcus mutans. Magnolol, as the main antibacterial active ingredient of magnolia, not only has the effect of cardiovascular protective, but also of a clear anti-fungal and oral pathogenic bacterium. There are more recent studies about these two traditional Chinese drug, which are natural anti-bacterial drugs. But the reporte about whether they can inhibit the development of root caries effectively and the comparative study between the two drugs and the other types of of drug is less both at home and abroad.Objective: This study compares the inhibit effect of artificial root caries of Teapol and Magnolol to study the mechanism of anti-caries to provide experimental basis and foundation for the application and choose about natural anti-microbial agents in clinical.Method:1 Preparation of isolated teeth: collect 60 extracted molars freshly due to periodontal disease loose III°(10 times magnification under the stereo microscope and non-carious root surfaces and no cracks), and curettage periodontal ligament and calculus, then remove the crown cementum and pulp sector organization in the junction of enamelo-cemental after 5min ultrasonic cleaning, formed cementum block about 4×4×2mm3 in the palatal lateral surface. Then coat acid-resistant layer nail polish double-deck except the roots surface (experimental area), immerse the cementum blocks in the 10% formaldehyde solution and sterilized to prepared.2 Preparation of bacterium suspension: Recover the Streptococcus mutans (the international standard strain) for 48h, then culture the Streptococcus mutans in brain heart infusion medium (BHI) under anaerobic conditions [f (N2) = 85%,φ(CO2) = 10%,φ(H2) = 5% ], and smear after passage three times, made the biochemical identification. After identified as Streptococcus mutans using of UV spectrophotometer, adjuste the bacterial suspension to OD = 1.0 with sterile saline.3 The establishment of model of artificial root caries: Tooth tissue will be placed in 350mL / L ethanol for 24 hours then in artificial saliva 37℃, for 24h. Then place the tooth in the prepared fresh bacterium suspension after the formation of acquired pellicle, each bacterium will be replaced after 48h for 20 days.Then the sample will be placed under the electron microscopy to determine whether the formation of early caries.4 Treatment of early artificial caries in drug: The samples of early dental caries tissue were randomly assigned to four groups: group of Teapol solution(2g/mL), group of honokiol solution(15.7μg/mL), group of fluoride solution(20g/mL), de-ionized water groups. Each group has 8 teeth. The specimen of teeth were placed in the four liquid immersion 5min, 3 times a day, for 5 days, the teeth were be in artificial saliva at 37℃incubator of the rest time.5 Determination of the quantity of calcium ion release: After the treatment of drugs, the four groups of dental tissue samples were dipped into the fresh bacterium suspension again for 48h, calculated calcium concentration in solution by UV spectrophotometer respectively in 4h, 8h,12h, 24h, 48h, when extraction two milliliters of four groups.6 Observation by scanning electron microscope: After the dipping in the bacterium suspension, the blocks were rinsed by 0.1% PBS buffer for three times, then put the blocks into 2.5% glutaraldehyde immediately to fix for 24h and 1% Osmic Acid to fix for 2h, then put these blocks into the 0.1% buffer again to rinse for three times, after that, put the blocks into 50% ethanol for dehydration step by step, then plate with gold. Observe the experimental area structure of tooth using scanning electron microscopy and take photographs.7 Statistical processing: Different leaching of calcium ions in different bacterium suspension were be analysis by SPSS13.0 software, and variance between the two groups was analysis by the snk-q test and the standard of significance was a = 0.05.Results:1 Results of quantity of calcium ion release1.1 calcium release increased with time from the demineralization for 6 hours in four groups.1.2 In five different time points, In 0-8h:there was no significant difference between four groups. In8-48h: the quantity of calcium ion release in the bacterium suspension groups of Teapol, sodium fluoride, and Magnolol were significantly reduced than those in deionized water leaching (P <0.05), and there was no significant difference between Teapol group and sodium fluoride group in effect of dental caries after pairwise comparison(p> 0.05), and there is less suppressive effect of caries of magnolol (p <0.05).2 Observe by scanning electron microscope:Control group: a large number of bacteria was adhere on the tooth surface, and different sizes pore and lacuna formed after demineralization of tooth structure; and accumulation of bacterial mass can be seen in the lacuna.Sodium fluoride group: bacteria was reduced on the surface of tooth structure, and we can see the cementum lamellar structure of surface still, and lacunae resurface mineral were formed in some tooth structure damaged.Teapol group: The organizational structure of teeth was relatively complete, and bacteria scattered around the fracture. Magnolol Group: destruction of tooth structure was obvious, and dentinal tubules structural was disorder.Conclusion:1 Calcium release increase withtime from the teeth take into the fresh bacterium.2 Teapol and magnolol can inhibited the development of early root surface caries in a certain extent. But Teapol'effection is better.3 The structure of cementum surface was different between the drug treatment group and control group. |
PDF Full Text Request