OBJECTIVETo investigate the effect of pulse Nd: YAG laser combined with NaF on caries resistance of human enamel in vitro.

METHODS24 caries-free, constant premolares were cut into enamel mass. Surface ultrastructure and fluoride distribution of enamel in laser-NaF treated group, laser treated group, NaF treated group and control group were observed by scanning electron microscope (SEM) and electron probe microanalyzer.

RESULTS(1) SEM observation: In laser-NaF treated group, the smear layer was almost removed, the enamel surface showed partially melted-like and bubble-like appearance, diffuse white-small particles distributed on enamel surface, and melted position, microcrack and microhole appeared whitely blocking-reflection. (2) Electron probe microanalyzer analysis: In enamel samples, the highest average Ci of F- and the hightest depth which F- entered in enamel were recorded in the laser-NaF treated group. The average Ci of F- in laser-NaF treated group was significantly increased compared with that in NaF-treated group or laser-treated group or control group (P < 0.001).

CONCLUSIONThe pulsed Nd:YAG laser combined with sodium fluoride could make the enamel surface partially melt, change the structure of the crystal, enhance the absorption of fluoride, and clear smear layer. This technology may resist the caries.

Dental Enamel ; ultrastructure ; Fluorides ; chemistry ; Humans ; Lasers, Solid-State ; Smear Layer ; Sodium Fluoride ; chemistry

Objective: To investigate the correlation between serum melatonin level and cardiac function, blood lipid in patients of heart failure with preserved ejection fraction (HFpEF). Methods: One hundred and seventy patients with HFpEF (HFpEF group) in Ninth Hospital of Xi′an City from May 2016 to May 2018 were selected. According to the cardiac function grading of New York Heart Association (NYHA), Ⅱ grade (cardiac function Ⅱ grade) was in 98 cases, and Ⅲ grade (cardiac function Ⅲ grade) was in 72 cases. Then, 32 healthy volunteers were selected as control group. The 2 groups were sampled at 2:00 and 7:00, and the level of melatonin was detected by enzyme-linked immunosorbent assay. The correlation between serum melatonin level and cardiac function, blood lipid were analyzed (Pearson correlation), including triglyeride (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein-cholesterol (HDL-C), N-terminal precursor brain natriuretic peptide (NTproBNP), hypersensitive C reactive protein (hs-CRP), ejection fraction, left ventricular end-diastolic volume index (LVEDVI), miral diastolic early and end-diastolic maximum blood flow velocity ratio (E/A) and peak value of early diastolic blood flow velocity in the mitral valve and peak value of the early diastolic velocity of the mitral annulus (E/e′). Results: The TG, TC, LDL-C, NTproBNP and hs-CRP in cardiac function Ⅲ grade patients were significantly higher than those in cardiac function Ⅱ grade patients: (1.51 ± 0.69) mmol/L vs. (1.15 ± 0.75) mmol/L, (4.03 ± 1.02) mmol/L vs. (3.47 ± 0.94) mmol/L, (1.42 ± 0.33) mmol/L vs. (1.17 ± 0.31) mmol/L, (3 438.54 ± 553.58) ng/L vs. (3 034.58 ± 557.35) ng/L and (4.26 ± 2.54) mg/L vs. (3.12 ± 2.13) mg/L, the HDL-C, ejection fraction and E/A were significantly lower than those in cardiac function Ⅱ grade patients: (2.44 ± 0.88) mmol/L vs. (2.97 ± 0.94) mmol/L, (56.23 ± 5.26)% vs. (61.11 ± 5.33)% and 0.82 ± 0.18 vs. 0.91 ± 0.17, and there were statistical differences (P<0.01). The melatonin levels at 2:00 and 7:00 in control group and cardiac function Ⅱgrade patients of HFpEF group were significantly higher than those in cardiac function Ⅲ grade patients of HFpEF group: (454.24 ± 123.54) and (432.68 ± 155.68) ng/L vs. (368.85 ± 98.52) ng/L, (483.25 ± 90.54) and (418.54 ± 103.57) ng/L vs. (345.85 ± 98.52) ng/L, the melatonin level at 7:00 in control group was significantly higher than that in cardiac function Ⅱ grade patients of HFpEF group, and there was statistical difference (P<0.01). In cardiac function Ⅱ grade patients of HFpEF group, the melatonin level was correlated with TG, TC, LDL-C and HDL-C (P<0.01); In cardiac function Ⅲ grade patients of HFpEF group, the melatonin level was correlated with NTproBNP, hs-CRP, ejection fraction, LVEDVI, E/A, E/e′, TG, TC, LDL-C and HDL-C (P<0.01 or <0.05). Conclusions The melatonin level is correlated with the level of blood lipid in HFpEF patients. Melatonin level is correlated with cardiac function Ⅲ grade patients, but this phenomenon is not observed in cardiac function Ⅱ grade patients.

Objective:To detect serum levels of vitamin A (Vit A), vitamin D(Vit D)25-hydroxy vitamin D[25-(OH)D] and vitamin E(Vit E) in children aged 0-6 years in Tibetan Plateau of Garzi Prefecture, thus providing references for physical examinations and prevention of 4 key diseases (rickets, malnutrition anemia, pneumonia and diarrhea) in children in plateau areas by relevant government departments.Methods:A total of 2 122 children who participated in physical examination in 12 townships of Xiangcheng County and 14 townships of Daocheng County, Garzi Tibetan Autonomous Prefecture, Sichuan Province from April 2017 to April 2019 with 0-6 years old were recruited for surveying physical measurements and collection of venous blood.Serum Vit A and Vit E levels were detected by high performance liquid chromatography.Serum levels of 25-(OH)D were detected by high performance liquid chromatography tandem mass spectrometry.The relationship between Vit A, Vit E and 25-(OH)D levels with the gender, age, seasonal change and altitude was analyzed.Results:The serum Vit A level, subclinical Vit A deficiency rate and marginal vitamin A deficiency rate were(1.05±0.27) μmol/L, 8.15%(173/2 122 cases) and 45.99%(976/2 122 cases), respectively in 2 122 children with 0-6 years old.There were significant differences in the serum Vit A level, the subclinical Vit A deficiency rate and the marginal vitamin A deficiency rate in children with different ages, seasons and altitudes (all P<0.05). The serum level of 25-(OH)D and 25-(OH)D deficiency rate insufficient rate were (24.65±6.45) ng/L, 6.03%(128/2 122 cases) and 16.59%(352/2 122 cases), respectively.There were significant differences in the serum level of 25-(OH)D, 25-(OH)D deficiency rate and 25-(OH)D insufficient rate in children with different ages and seasons (all P<0.05). The mean serum Vit E level, Vit E deficiency rate and Vit E insufficient rate were (7.81±1.74) mg/L, 2.78%(59/2 122 cases) and 29.59%(628/2 122 cases), respectively.There were significant differences in serum Vit E level, Vit E deficiency rate and Vit E insufficient rate in children with different ages and seasons (all P<0.05). The mean serum levels of Vit A and Vit D remained the lowest before the age of 1 year, and their deficiencies at this age were the most significant.The mean serum level of Vit E remained the lowest in >1-2 years old, and its deficiency and insufficient at this age were the most significant.Vit A, D and E levels were significantly affected by seasonal changes, which were significantly higher in the summer than in the spring, autumn and winter.In addition, Vit A and 25-(OH)D were significantly affected by the altitude, which were the lowest above 4 km altitude. Conclusions:The overall serum levels of Vit A, 25-(OH) D and E in children with 0-6 years old in Tibetan Plateau areas of Ganzi Prefecture are lower than those in plain areas.Vit A, 25-(OH) D and Vit E levels significantly differed in the age, season and altitude, which are related to the lack of local resources, insufficient maternal nutrition during pregnancy and insufficient intake after birth, as well as temperature and light caused by changes in local seasons and altitude.Therefore, it is necessary to make reasonable supplements during pregnancy to prevent vitamin deficiency.