Effect Of CPP-ACP On Early Demineralization Of Dental Erosion And Acid Resistance Of Enamel

Background Dental erosion is a localized loss of the tooth surfaceby a chemical process of acidic dissolution of nonbacterial origin. Thereare no symptoms at its initial stage and unless halted, it will lead to dentinhypersensitivity or even worse, dentin or pulp exposure and toothfracture.In recent decades, epidemiologic surveys have investigated dentalerosion and the results have shown that it’s a common disease amongpeople, with increasing prevalence and having gained wider interest fromthe dental professionals followed dental caries, which has become a veryharmful condition of oral health. With the growing consumption of acidicbeverages, acidic drinks have become a major risk factor for dental erosion.We can prevent the further progression of dental erosion and reversedemineralized enamel to normal, with remineralization treatment in itsearly stage. Fluoride is the most classic remineralization agent, but hassome side effects such as dental or skeletal fluorosis, if overused. Therefore,there are certain restrictions in fluoride application. So, searching for a safer kind of remineralization agent without toxic side effects has become ahot research.Casein phosphopeptides(CPPs) are casein-derived peptides whichhave binding and solubilizing property for calcium. CPPs are aggregatedwith amorphous calcium phosphate (ACP) and then, the nanocomplexesare formed,which stabilize high concentration of bioactive calcium andphosphate and has been shown to reduce demineralization and promoteremineralization of enamel lesions.CPP-ACP has been proved to be a kindof safe, effective and non-toxic remineralization agent and has gained wideattention from researchers.Many domestic and foreign studies have shown that CPP-ACP has thepotential to be the ideal substitute of fluoride for dental erosion prevention.There are few comprehensive researches about the effect of CPP-ACP onacid resistance of enamel and early demineralization of dentin in primaryand permanent teeth both at home and abroad. Therefore, further researchis needed on the effect of CPP-ACP on dental erosion and oral health.Objectives Using other researchers’ methods as references and highconcentration fluoride (fluoride vanish,NaF5000ppm) as comparison, thisin vitro study used surface microhardness and scanning electronmicroscope to evaluate effect of CPP-ACP on acid resistance of enameland early demineralization produced by acidic drinks in primary andpermanent teeth, providing a novel method for dental erosion prevention and scientific evidence that whether CPP-ACP can be widely applied inoral health as a fluoride substitute.Materials and Methods1.Effect of CPP-ACP on early enameldemineralization produced by acidic drinks in permanent teeth. Fifteenthird molars were collected at clinic and were processed into30enamelslabs. The enamel slabs were randomly divided into3groups (n=10):group-deionized water as negative control, group-CPP-ACP, group-fluoride vanish as positive control. Each specimen was first immersed in acola drink for2min,7times a day complished in8hours, for7days. Thenthe specimens were subjected to three different remineralization protocols,using deionized water, CPP-ACP and fluoride vanish. Vickersmicrohardness (SMH) measurements were obtained at baseline, after thecola drink erosion and after remineralization stage. The enamel specimenswere analyzed by the scanning electron microscope (SEM) at differentstages.2. Effect of CPP-ACP on acid resistance of permanent teeth enamel.Fifteen third molars were collected at clinic and were processed into30enamel slabs. The enamel slabs were randomly divided into3groups(n=10): group deionized water as negative control, group CPP-ACP, groupfluoride vanish as positive control. The specimens were treated by one ofthe following agents respectively: deionized water and CPP-ACP(3mineach time,2times daily for7days),fluoride vanish(3min a time, just a single time).After treatment,the specimens were immersed in a cola drinkfor2min,7times a day completed in8hours for7days. Vickersmicrohardness (SMH) measurements and SEM observation were obtainedat baseline, after pretreatment and after the cola drink erosion.3. Effect of CPP-ACP on acid resistance of enamel and earlydemineralization in primary teeth. The primary lower incisors werecollected and were processed into30enamel slabs. The enamel slabs wererandomly divided into3groups (n=10): group A(deionized water), groupB(erosion cycle—CPP-ACP treatment), group C(CPP-ACPpre-treatment—erosion cycle).group A: specimens were stored indeionized water without other treatment after the cola drink immersion,group B: CPP-ACP was applied for7days after7days erosion cycle,group C: specimens were subjected to erosion cycle after CPP-ACPpretreatment. Vickers microhardness (SMH) measurements and SEMobservation were obtained at baseline, after the cola drink erosion and afterCPP-ACP application.Results1. Enamel hardness significantly decreased after immersionin a cola drink (P <0.05). The SMH of the enamel slabs treated withCPP-ACP and fluoride vanish were significantly increased compared withthat of the control (P<0.05) and there was significant difference betweenthe former two groups (P <0.05). SEM demonstrated that there was a lot of mineral deposition on the surface of enamel of group CPP-ACP and groupfluoride vanish.2. Enamel hardness significantly increased after7days pre-treatmentin all groups and SMH in group CPP-ACP was significantly more than theother two groups (P<0.05).Hardness of specimens pre-treated withCPP-ACP decreased lowest compared with group deionized water andgroup fluoride vanish(P<0.05).SEM demonstrated that all specimensdemineralized after cola drink immersion, but the degree ofdemineralization in group CPP-ACP was less as compared with the othertwo groups.3. Enamel hardness significantly decreased at the end ofexperiment(P<0.05).In group B, the hardness of eroded enamelsignificantly increased after CPP-ACP treatment compared with group A(P<0.05).In group C, the application of CPP-ACP to sound enamelsurfaces inhibited the decrease of SMH compared with group A.SEMdemonstrated that the morphology of the enamel was different in eachgroup at different times.Conclusions1.CPP-ACP can promote mineral deposition on thedemineralized enamel surface to increase the SMH of the eroded humanenamel, thus, showing the remineralization potential.2. Single application of fluoride vanish had no effect on inhibitingenamel demineralization in permanent teeth. The application of CPP-ACP had a protective effect on enamel demineralization, enhancing the acidresistance.3. CPP-ACP was effective in promoting enamel demineralization andinhibiting demineralization in primary teeth.