ABSTRACT
Objective:To analyze the iodine nutritional status of children aged 8 - 10 in Tongren City, Guizhou Province, and provide a basis for scientific iodine supplementation for children.Methods:From 2020 to 2022, a systematic sampling method was adopted in 10 districts and counties of Tongren City. Each year, each district and county was divided into 5 districts based on east, west, south, north, and center. One township (street) was selected from each district, and 40 non boarding students aged 8 to 10 were selected from each township (street) to measure the iodine content of household salt and urine samples. The content of salt iodine in children of different yesas as well as the distribution of urine iodine in children of different districts and counties and different genders were analyzed and compared. Additionally, B-ultrasound was used to measure the thyroid volume of some children and the situation of thyroid enlargement was analyzed.Results:From 2020 to 2022, a total of 6 000 salt samples were collected and monitored from children's households, and 5 989 samples of iodized salt were detected, the coverage rate of iodized salt was 99.8%; and 5 750 samples of qualified iodized salt were found, the qualified rate of iodized salt was 96.0%, the consumption rate of qualified iodized salt was 95.8%; and the median salt iodine was 27.3 mg/kg, the difference in the median salt iodine among children between different years was statistically significant ( H = 10.04, P < 0.001). A total of 6 000 urine samples from children were tested, the median urinary iodine was 225.2 μg/L, the median urinary iodine among children in different districts and counties were statistically significantly different ( H = 85.73, P < 0.001); 3 077 male and 2 923 female urine samples were tested, and the median urinary iodine between different genders was statistically significant different ( Z = - 67.10, P < 0.001). The median urinary iodine of male samples were higher than those of female samples(227.8 vs 222.9 μg/L). The thyroid gland of 2 000 children was examined, and the rate of goiter was 1.0% (21/2 000). Conclusions:From 2020 to 2022, the consumption rate of qualified iodized salt, urinary iodine content and goiter rate of children in Tongren City have all met the national standard for eliminating iodine deficiency disorders. The overall iodine nutrition level exceeds the appropriate amount (urinary iodine of 200 - 299 μg/L).
ABSTRACT
Objective@#To analyze the effect of ceramic materials thickness and resin cement shades on the final color of ceramic veneers in the discolored teeth, and to investigate the color agreement of try-in pastes to the corresponding resin cements. @*Methods@#Sixty artificial maxillary central incisor teeth (C2 shade) were used to simulate the natural discolored teeth and prepared according to veneer tooth preparation protocol. Veneers of different thickness in the body region (0.50 and 0.75 mm) were fabricated using ceramic materials (LT A2 shade, IPS e.max Press). The ceramic veneer specimens were bonded to the artificial teeth using the 6 shades of resin cements (Variolink Veneer: shades of LV-3, LV-2, HV+3; RelyX™ Veneer: shades of TR, A3, WO) (n=5). A clinical spectrophotometer was used to measure the color parameters of ceramic veneers at the cervical, body and incisal regions. Color changes of veneers before and after cementation were calculated and registered as ΔE1, and the changes between try-in paste and the corresponding resin cements were registered as ΔE2. @*Results@#Three-way ANOVA indicated that ΔE1 and ΔE2 values were significantly affected by the ceramic thickness, resin cement shades and measuring regions (P<0.05). The ΔE1 values of six shades ranged from 0.59-8.27. The ΔE1 values were more than 2.72 when the ceramic veneers were cemented with resin cements in shades of HV+3 and WO. The ΔE2 values of six shades ranged from 0.60-2.56. The shades of HV+3, WO and A3 resin cements were more than 1.60. @*Conclusions@#Different thickness of ceramic materials, resin cement shades and measuring regions could affect the final color of ceramic veneers. The color differences of some resin cements and corresponding try-in pastes might be observed in clinical practice.