Effect of neodymium-doped:yttrium aluminum perovskite laser combined with two kinds of remineralizers on remineralization of early enamel caries

Xu Yinghua; Liu Jing; You Quan; Wen Zhihao; Gao Lu

doi:10.12307/2023.838

Abstract：BACKGROUND:In recent years,a variety of lasers have been widely used in various diseases related to stomatology,including the prevention and treatment of dental caries. OBJECTIVE:To investigate the effect of neodymium-doped:yttrium aluminum perovskite(Nd:YAP)laser combined with two remineralizers on early enamel caries in vitro. METHODS:Early enamel caries models in vitro were artificially established by 60 enamel blocks and randomly divided into 6 groups(n=10).Group A did not undergo any treatment but underwent extracorporeal pH circulation.Group B underwent remineralization of dentin(the main component of casein phosphopeptide-amorphous calcium phosphate composite)and extracorporeal pH circulation.Group C underwent remineralization treatment of Sensodyne toothpaste(the main component of bioactive glass)and then underwent extracorporeal pH circulation.Group D received Nd:YAP laser irradiation and extracorporeal pH circulation.Group E was treated with Nd:YAP laser irradiation,with remineralization of dentin,and then with extracorporeal pH circulation.In group F,Nd:YAP laser irradiation was performed,and then Sensodyne toothpaste was used for remineralization,and the extracorporeal pH circulation was performed;the remineralization treatment was conducted twice a day,and the experimental period was 20 days.Group G was a normal control group,without caries or remineralization,but only underwent extracorporeal pH circulation.After the experiment,the microhardness,morphology and Ca/P ratio of the dental enamel surface were measured in each group. RESULTS AND CONCLUSION:(1)The surface microhardness value of dental enamel in groups B,C and D was higher than that in group A(P<0.000 1);the surface microhardness value of dental enamel in groups E and F was significantly higher than that in groups B,C and D(P<0.000 1),and the surface microhardness value of dental enamel in group F was significantly higher than that in group E(P<0.000 1).(2)Scanning electron microscopy showed that there were a lot of demineralized pores on the enamel surface of group A.There were mineral deposits on the enamel surface of group B,which were uneven and loose.In group C,there were a lot of mineral deposits on the enamel surface,and demineralized pores were found between the calcified masses.The enamel surface of group D was relatively flat;the demineralized pores were significantly smaller than that of group A,and the enamel column interstitium was damaged.In group E,the mineral deposits on the enamel surface were thicker and the demineralized pores were significantly reduced.The mineralized substances deposited on the enamel surface of group F were most dense and uniform and the demineralized pores were small.(3)The Ca/P ratio on the enamel surface of groups B and C was significantly higher than that of group A(P<0.000 1);the Ca/P ratio on the enamel surface of group E was significantly higher than that of groups B,C and D(P<0.000 1),and the Ca/P ratio on the enamel surface of group F was higher than that of group E(P<0.001).(4)These findings indicate that bioactive glass,casein phosphopeptide-amorphous calcium phosphate composite,and Nd:YAP laser after enamel demineralization can promote the remineralization of early enamel caries.Nd:YAP laser combined with bioactive glass or casein phosphopeptide-amorphous calcium phosphate composite can further strengthen the remineralization of dental enamel caries,and the combination of Nd:YAP laser and bioactive glass has the best effect.