Prevalence and severity of molar-incisor hypomineralization, is there an association with socioeconomic status? A cross-sectional study in Chilean schoolchildren.

PURPOSE: Data about molar-incisor hypomineralization (MIH) prevalence and its severity remains limited for some Latin American countries. Furthermore, its association with socioeconomic status (SES) is still unclear. Thus, this study aims to determine the prevalence and severity of MIH in Santiago, Chile and explore its association with SES. METHODS: A cross-sectional study with schoolchildren between 6 and 12 years was conducted. Children were evaluated using the European Academy of Paediatric Dentistry to diagnose MIH, and the Mathu-Muju and Wright criteria to determine its severity. RESULTS: A total of 1,270 children were included. The MIH prevalence was 12.8% without association with gender (p = 0.609). Prevalence was higher among schoolchildren ages 8 and 9 (p = 0.002), and in lower SES (p = 0.007). MIH mild cases were the most prevalent (63%), and severity was not related to gender (p = 0.656), age (p = 0.060), or SES (p = 0.174). CONCLUSIONS: The prevalence of MIH in the province of Santiago, Chile is 12.8% and was found to have a higher incidence in 8-9-year-old students and among those categorized by low SES. Furthermore, MIH prevalence was associated with low SES. IMPLICATIONS: Public health policies to address MIH in Chile should start with schoolchildren aged 8 to 9, and with low SES.

A study of the variability seen in the international normalized ratio obtained using different sensitivity thromboplastin reagents on different instrument types.

We performed an extensive study to check international normalized ratio (INR) recovery using three different rabbit thromboplastin reagents of different sensitivities [international sensitivity index (ISI) circa 1.1, 1.3 and 2.0] on two different instrument types. Both instrument types used an optical end point: one nephelometric at 660 nm, one photometric at 880 nm. Each thromboplastin reagent in the study had an instrument-specific ISI value assigned to it by the reagent manufacturer. Samples obtained from stable orally anticoagulated patients were tested on four different instruments of each type with the three different sensitivity reagents. Excellent correlation between INR values was seen between all results (r values between 0.97 and 0.99). Regression analysis gave slopes between 0.92 and 1.07, and a maximum deviation of intercept from zero of 0.21. Variations in CV of less than 2% were seen within each instrument type. This study shows that if instrument-specific ISI values are used, comparable INR values can be obtained using reagents of different sensitivity on multiple instruments of the same or different types. This study demonstrates the validity of the INR/ISI system.