An Experimental Research Of Remineralization Materials On Morphology And Microhardness Of Blaeched Enamel

In recent years, people demand more and more beautiful. As animportant part of facial appearance, the color and shape of teeth receivemore and more attention. At present, many treatments of toothdiscoloration are available such as the tooth bleaching, laminate veneersand porcelain-fused-to-metal crowns. Among these, bleaching is wellreceived for its less invasive, less time-consuming, less cost. Bleaching canbe divided into in-home bleaching and in-office vital bleaching technique.Products containing low concentration of hydrogen peroxide(3%-7%) orcarbamide peroxide(10%-20%),are always used for in-home bleaching.Although it is easy to use and has high success rates, it needs more time.In-office vital bleaching technique products with high concentration ofhydrogen peroxide(30%-35%) are used a lot, because of highly effectivebut less time-consuming.High concentration products can decompose pigments in theorganization of teeth through the strong oxidation. Although the higherconcentration, the higher effect, it has been reported that the roughness of enamel surface is increased, some random depression spots becomenoticeable after bleaching and the microhardness of enamel is decreasedsignificantly; it also increase bacteria adhension. In conclusion, how torecover the morphology and microhardness seems particularly important.Recently, little study has been published addressing the use ofremineralization materials on bleached enamel.ObjectivesTo analyze the effect of fluor protector and tooth mousse onmorphology and microhardness of bleached enamel, to compare the effectof these two kinds of remineralization materials and to confirm theapplicability and reliability in clinic.Materials and Methods1.20premolars extracted for orthodontic reasons were selected,whose buccal surfaces were made into enamel slabs. Those enamel slabswere embedded in self-curing plastic, polished, and subjected tobleaching-treated group and control group randomly. After treatment,morphology was evaluated under SEM.2.20premolars extracted for orthodontic reasons were selected,whose buccal surfaces were made into enamel slabs. Those enamel slabswere embedded in self-curing plastic, polished. Before and after bleachingmicrohardness were evaluated.3.20premolars extracted for orthodontic reasons were selected, whose buccal surfaces were made into enamel slabs. Those enamel slabswere embedded in self-curing plastic, polished, and subjected to group Aand group B randomly. Group A were bleached and used fluor protector,then evaluated under SEM. Group B’s microhardness were evaluated beforebleaching, after bleaching and after the using of fluor protector.4.20premolars extracted for orthodontic reasons were selected,whose buccal surfaces were made into enamel slabs. Those enamel slabswere embedded in self-curing plastic, polished, and subjected to group Cand group D randomly. Group C were bleached and used tooth mousse,then evaluated under SEM. Group D’s microhardness were evaluatedbefore bleaching, after bleaching and after the using of tooth mousse.Results1. Before bleaching, only scratches were seen under SEM. Howeverthe roughness of enamel surface was increased and some randomdepression spots became noticeable after bleaching.2. The microhardness of enamel was decreased significantly after theusing of35%bleaching agent compared with that before bleaching(P<0.05).3. After the using fluor protector, the surface of enamel became lessrough and sediments were seen. The microhardness of enamel wasdecreased significantly after bleaching compared with that before bleaching(P<0.05).The microhardness of bleached enamel with fluor protector was higher than that without fluor protector, however, the microhardness ofenamel before bleaching and after the using of fluor protector were notstatistically significant(P>0.05).4. After the using tooth mousse, some sediments were seen instead ofdepression spots. The microhardness of enamel was decreased significantlyafter bleaching compared with that before bleaching (P<0.05).Themicrohardness of bleached enamel with tooth mousse was higher than thatwithout it, however, the microhardness of enamel before bleaching andafter the using of tooth mousse were not statistically significant(P>0.05).5. Sediments were noticeable in both groups. There is no statisticallysignificant difference before or after bleaching between the two groups,whether using fluor protector or tooth mousse.Conclusions1. The using of high concentration HP increases the roughness of theenamel, demineralization can be seen and decreases the microhardness.2. Using fluor protector and tooth mousse after bleaching make themorphology and microhardness of enamel recovered quickly. Nostatistically significant differences can be found between these two kinds ofremineralization materials.3. The using of remineralization materials can due to the recovering ofthe morphology and microhardness of enamel. Tooth mousse is a naturalproduct, promising its clinic safety.