Study On Color Change And Stability Of Black Tea After Adherence To Tooth Surface

Objective:In daily life,there is pigmentation on the teeth of long-term tea drinkers,especially in the teeth pits and fissures.Therefore,it is assumed that the components of tea have an attachment effect on the teeth,and this attachment effect can reduce the time of teeth and food contact and bacterial attachment so as to protect the teeth.Studies have shown that dental caries in children mainly occur in pits and fissures on the surface of the teeth,so this topic takes the pits and fissures in the dental surface as the object of observation.Previous experiments showed that black tea had the best adhesion effect on the pit and fissure of young permanent teeth compared with white tea,green tea and oolong tea,and the amount of pigments adhering to the pit and fissure was proportional to the concentration of black tea in a certain range.However,the pigments of tea adhering to the pit and fissure was similar to that caused by caries,which easily led to misdiagnosis in clinical diagnosis.The plaque indicator alkaline fuchsin basic commonly used in oral cavity can be used to change the pigments of tea adhering to the pit and fissure.In this experiment,we studied the color change and stability of black tea after it was attached to pits and fissures,and explored the feasibility of black tea as a method of protecting pit and fissure.Methods:1?Cultured human gingival fibroblasts were added into 96-well plate.Culture solution containing black tea solution(tea-water ratio 1:50?1:100?1:200?1:400?1:800)or fuchsin basic solution(0.04 mg/ml?0.02 mg/ml?0.01 mg/ml?0.005 mg/ml?0.0025 mg/ml)was added into 96-well plate.CCK-8 reagent was added to the plate.The absorbance value was measured by enzyme scaler and the relative cell proliferation rate was calculated.2?Deionized water was used as the reference solution for black tea with tea-water ratio of 1:100 and fuchsin basic with 0.0025 mg/ml.The absorbance of 0 h?24 h and 48 h was measured by spectrophotometer,the absorption curve was drawn.3?After immersing the samples of premolars in saliva for 2 hours,black tea solution with a tea-water ratio of 1:100 was applied to the pits and fissures of the samples for 50 times.The attachment thickness of the pits and fissures was measured by tool measuring microscope and photographs were recorded.0.0025 mg/ml fuchsin basic solution was applied to the pits and fissures of the samples.The attachment thickness of black tea and fuchsin basic was measured by tool measuring microscope and photographs were recorded.The attachment of black tea and fuchsin basic in pits and fissures was observed by scanning electron microscopy.The elemental composition and content in pits and fissures were analyzed by scanning electron microscopy and energy dispersive spectrometry.4?After immersing the premolar sample in saliva for 2 hours,black tea solution with a tea-water ratio of 1:100 was applied to the pit and fissure of the sample for 50 times,and 0.0025 mg/ml fuchsin basic solution was applied to the pit and fissure of the sample.The samples were subjected to 500 cycles of cold and heat cycles.The attachment thickness of black tea and fuchsin basic before and after the cold and heat cycles was measured by tool measuring microscope and photographs were recorded.Results:1?The fuchsin basic solution of 0.04 mg/ml,0.02 mg/ml and 0.01 mg/ml acted on HGF for 12 h?24 h and 48 h,RGR boundaries ranged from 31.396% to 73.658%.The cytotoxicity grade was 2 or 3,which was evaluated as mild to moderate cytotoxicity.There were significant differences in RGR between the three groups and the other groups.The fuchsin basic solution of 0.005 mg/ml and 0.0025 mg/ml acted on HGF for 12 h?24 h and 48 h,RGR range was 80.418%-103.837%.The cytotoxicity grade was 0 or 1,which was evaluated as non-cytotoxic.There was no significant difference in RGR between the two groups.Black tea solution with 1:50 tea water ratio acted on HGF for 12 h?24 h and 48 h,RGR boundaries ranged from 55.568% to 66.617% and cytotoxicity grading was 2 grade,which was evaluated as mild cytotoxicity.Black tea solution with 1:100?1:200?1:400?1:800 tea water ratio acted on HGF for 12 h?24 h and 48 h,RGR boundaries ranged from 79.991% to 103.424% and cytotoxicity grading was 0 or 1 grade,which was evaluated as non-cytotoxic.Black tea solution with 1:50 tea water ratio and 1:100 tea water ratio were significantly different from other groups in RGR.There was no significant difference in the RGR of black tea solution with tea water ratio of 1:200?1:400 and 1:800.2?The maximum absorption wavelength of black tea with tea-water ratio of 1:100 is 320 nm.The maximum absorption wavelength of 0.0025 mg/ml fuchsin basic is 540 nm.The maximum absorption wavelength of the equal volume mixture of the two species is 300 nm.The maximum absorption wavelength of black tea with tea-water ratio of 1:100 for 0 h?24 h and 48 h is 320 nm.The maximum absorption wavelength of 0.0025 mg/ml fuchsin basic for 0 h?24 h and 48 h is 540 nm.The maximum absorption wavelength of mixture of black tea with tea-water ratio of 1:100 and 0.0025 mg/ml basic fuchsin for 0 h,?24 h and 48 h is 300 nm.3?The V-shaped pits and fissures?U-shaped pits and fissures?IK-shaped pits and I-shaped pits and fissures are clean and colorless without attachments,four kinds of pits and fissures have brown attachments after being smeared by black tea.There are significant differences in the thickness of four kinds of brown attachments.Four kinds of pits and fissures smeared with basic fuchsin after smeared by black tea appeared purple red in the pits and fissures.There were significant differences in attachment thickness between the four pits and fissures smeared with black tea solution before and after smearing with fuchsin basic solution.There were significant differences in attachment thickness between the four kinds of pit and fissure of black tea solution and fuchsin basic solution applied successively.The attachments in V-shaped and U-shaped pits and fissures were not obvious,while those in IK-shaped pits and I-shaped pits and fissures were obvious but not continuous when magnified 100 times by SEM.The attachments in V-shaped fissures and U-shaped fissures were more obvious when magnified 500 times by SEM.The attachments in V-shaped fissures?U-shaped fissures?IK-shaped fissures and I-shaped fissures were closely combined with enamel,the boundary between them was not obvious,there were some cracks in the attachments.Point energy spectra of pit-fissure enamel layer include four main peaks of P?Ca?C and K.Small peaks of P and Cl can be observed in the energy spectra of black tea layer of pit-fissure attachment besides three main peaks of C?Ca and O.Small peaks of Si and Al can be observed in the energy spectra of fuchsin basic layer of pit-fissure attachment outside the main peaks of C?K?Ca and O.4?The V-shaped pits and fissures?U-shaped pits and fissures?IK-shaped pits and I-shaped pits and fissures smeared with black tea and fuchsin basic basically faded after cold and hot cycles,leaving Brown attachments and a little purple red.The thickness of pit and fissure attachments before and after cold and hot cycles was significantly different.Conclusions:Low concentration of fuchsin basic solution and low tea ratio black tea solution had no cytotoxicity on cultured human gingival fibroblasts in vitro.Black tea and fuchsin basic can react to form new substances and the new substances are relatively stable in a certain period of time.Black tea and fuchsin basic can adhere to pits and fissures,the thickness of attachments in different pits and fissures is different.Fuchsin basic can improve the color of pit and fissure attachments,but its stability needs further verification.