The Role Of GC Tooth Mousse In Promoting Enamel Remineralization During Fixed Orthodontic Treatment: An In Vitro Study

The Role of GC Tooth Mousse in Promoting Enamel Remineralization during Fixed Orthodontic Treatment:An In Vitro StudyPart One The Role of GC Tooth Mousse in Enamel Remineralization during Fixed Orthodontic Treatment In Vitro As Measured by Scanning Electronic Microscopy and Hardness TestingObjective:To investigate the role of the tooth mousse in the remineralization of the enamel by scanning electronic microscopy and the microhardness instrument on the bovine demineralization models,and provide experimental evidence for the clinical use.Methods:80 freshly extracted bovine incisors were collected for the experiment. Orthodontic Edgewise brackets were adhered to the clinical centre of the labial surfaces of the incisors,with a 4mm×4mm windowing area formed by nail vanish on the gingival side of the bracket.The windowing areas were demineralized for two weeks in the balance solution of the partial saturation acid to form a 4mm×4mm demineralization model area.The 80 teeth were divided into four groups,with 20 teeth in each group. Group A was treated with GC tooth mousse.Group B was treated with fluorine-containing tooth paste.Group C was treated with GC tooth mousse and the fluorine-containing tooth paste,while Group D was designed to be the control group, treated with artificial saliva only.All of the remineralization of the four groups were done in 37℃water bath,with a frequency of 3 times a day,and 5 minutes every time.The microhardness instrument was used to test the hardness of the enamel surface at the end of 3 weeks,6 weeks,9 weeks and 12 weeks separately.The hardness values of four groups were analyzed with Repeated Measured Variance Analysis of three factors in SPSS13.0 microware package.At the same time,the compare between the means of different groups at the same test time was done by Multiple Factors Variance Analysis. The electronic scanning microscopy was used to test the micrological condition of the enamel surface at the end of 6 weeks and 12 weeks.Results:①Under the electronic scanning microscopy,it could be seen that after 6-week remineralization,the micrological condition of the enamel surface in four groups was all improved,with the roughness ameliorating and the shaggy microspaces decreasing.Under the high power lens,the nest-like concavities could be seen to become more superficial and the radius was smaller with the deposition of the mineral particles. Among four groups,the effect of group C was best,group B and A next and group D last. At the end of 12 weeks,the micrological condition of the enamel surface was improved further than that of at the end of 6 weeks.The roughness ameliorated and the shaggy microspaces decreased.High power lens showed that there was no nest-like concavity in group A and group C,whereas the enamel surfaces were not slippery still and anisotropic construction was seen.Mineral particles also could be seen.The nest-like concavities still existed in group A and group D,but more superficial and smaller than that of at the end of the 6 weeks.There was also deposition of mineral particles.②The Repeated Measured Variance Analysis showed that,the microhardness of the enamel surfaces in four groups all increased with the processing of remineralization,and the speed of group A and C was similar,almost achieving the level of before demineralization.Group B and D were slower,and the hardness values at the end of 12 weeks were still greatly different from that of before demineralization.Multiple Factors Variance Analysis showed that,at the point of 3 weeks,6 weeks,9 weeks and 12 weeks,it was statistically different(p=0.000,p<0.05) between group A,B,C and group D.At the end of 3 weeks,it was statistically different(p=0.003,p<0.05) between groupC and group B,while it was not statistically significant(p>0.05) between group A and group B,C.At the end of 6 weeks,the hardness values between group A and group B,C were statistically different(p=0.003,0.001,p<0.05),the same to the compare between group B and group C.At the end of 9 weeks,it was statistically different(p=0.000,p<0.05) between group B and group C.Group A,C were statistically different(p=0.000,p<0.05) from group B at the end of 12 weeks,while it was not statistically different(p>0.05) among other groups.Conclusion:①GC tooth mousse,fluorine-containing tooth paste,the combination of the two paste and the artificial saliva can all improve the micrological condition and increase the microhardness of the enamel surface with the processing of the remineralization.②GC tooth mousse can proceed the remineralization of the enamel and improve the micrological condition and increase the microhardness of the enamel surface much better than the fluorine-containing tooth paste and the artificial saliva.③The combination of GC tooth mousse and the fluorine-containing tooth paste has the best effect compared to the separate use of GC tooth mousse, fluorine-containing tooth paste.Part two Quantitative Study of GC Tooth Mousse in Enamel Remineralization during Orthodontic Treatment In Vitro As Measured by Computer-assisted Image analysis of the Clinical Polarized PhotographsObjective:To investigate the role of the tooth mousse in the remineralization of the enamel by polarized digital imaging and computer assisted image analysis on the bovine demineralization models,and provide experimental evidence for the clinical use.Methods:80 freshly extracted bovine incisors were collected for the experiment. Orthodontic Edgewise brackets were adhered to the clinical centre of the labial surfaces of the incisors,with a 4mm×4mm windowing area formed by nail vanish on the gingival side of the bracket.The windowing areas were demineralized for two weeks in the balance solution of the partial saturation acid to form a 4mm×4mm demineralization model area.The 80 teeth were divided into four groups,with 20 teeth in each group. Group A was treated with GC tooth mousse.Group B was treated with fluorine-containing tooth paste.Group C was treated with GC tooth mousse and the fluorine-containing tooth paste,while Group D was designed to be the control group, treated with artificial saliva only.All of the remineralization of the four groups were done in 37℃water bath,with a frequency of 3 times a day,and 5 minutes every time.The polarize images of each tooth was taken at the end of 3 weeks,6 weeks,9 weeks and 12 weeks separately,and the computer assisted image analysis system was used to record the size and mean grey level of the demineralized area.The size and mean grey level values of four groups were analyzed with Repeated Measured Variance Analysis of three factors in SPSS13.0 microware package.At the same time,the compare between the means of different groups at the same test time was done by Multiple Factors Variance Analysis.Results:①Repeated Measured Variance Analysis showed that,the size of the demineralized area in four groups all decreased with time.And the speed was slow in the first 3 weeks,and then increased afterwards.There was a rapid decreasing period in group A between 6 weeks and 9 weeks.The speed of size decreasing in group B and group C was similar,and group D was always the slowest and least obvious in four groups. Multiple Factors Variance Analysis showed that,at the end of 3 weeks,there was no statistical difference(p>0.05) among four groups.And at the time of 6 weeks,9 weeks and 12 weeks,group A,group B and group C were all statistically different(p=0.000, p<0.05) from group D.Group A and group C was statistically different(p=0.039,p<0.05) at the end of 3 weeks and 6 weeks,but not statistically different(p>0.05) at the end of 9 weeks and 12 weeks.Group B and group C was statistically different((p=0.000,p<0.05) at the time of 6 weeks and 9 weeks.There was no statistical difference(p>0.05) between group A and group B,and there was statistical difference between group A and group C, group B and group C(p=0.010,0.005,p<0.05).②Repeated Measured Variance Analysis showed that,the mean grey level of four groups all decreased with time,with group C coming first,group A and group C next,and group D the last.Multiple Factors Variance Analysis showed that,at the end of 3 weeks the mean grey level of four groups had no statistical difference(p>0.05).Group A,group B and group C were all statistically different(p=0.000,p<0.05) from group D at the end of 6 weeks,9 weeks and 12 weeks.At the end of 6 weeks,group A and group C statistically differed(p=0.037,0.000,p<0.05) from group B,and group A was statistically differed(p=0.012,p<0.05) from group C.At the end of 9 weeks,group A and group C statistically differed(p=0.017,0.000,p<0.05) from group B.Group A and group C were statistically different(p=0.004,p<0.05) at the end of 12 weeks,but there was no statistical difference(p>0.05) between group A and group B.Conclusion:①GC tooth mousse,fluorine-containing tooth paste,the combination of the two paste and the artificial saliva can all decrease the size and the mean grey level of the enamel surface with the processing of the remineralization.②The combination of GC tooth mousse and the fluorine-containing tooth paste has the best effect compared to the separate use of GC tooth mousse, fluorine-containing tooth paste.③The artificial saliva can somehow promote the remineralization of the enamel.④Polarize digital imaging and computer assisted image analysis system can be an effective method to diagnose enamel demineralization and longitudinally detect the changes of the demineralized area.