In vitro quantitative assessment of enamel microhardness after exposure to eroding immersion in a cola drink.

Studies assessing the erosive potential of soft drinks have employed long time intervals of immersion that may not accurately depict the impact of frequent soft drink consumption on enamel. This in vitro study assessed the effect of a cola drink on enamel, replicating an actual drinking pattern. Six groups of 4 human enamel slabs were immersed (5 min each bath) in fresh cola drink, with immersions taking place with or without agitation, and under 3 regimes of frequency intake (low intake, 1 immersion/day; medium, 5/day; high, 10/day). Quantitative assessments of surface erosion were done over an 8-day interval using surface microhardness testing (Vickers). Results showed a sharp decrease from baseline (mean value 352.1 Vickers Hardness Number, SD 32.5) to day 1 (269.3, SD 41.0) and then continued decreasing throughout the assay, although less markedly, to reach 204.5, SD 45.4 on day 8. Microhardness decreased regardless of frequency regime, except on day 8, on which slabs from the low intake group were harder (233.2, SD 25.0) than slabs from the high intake group (169.8, SD 49.5; p < 0.05). Results from the ANOVA on the factorial experiment indicated that the role of agitation was statistically significant (d.f. = 1, F = 7.2, p = 0.020) while the level of intake was of borderline significance (d.f. = 2, F = 3.2, p = 0.075). The main effect resulting from the joint roles of agitation and intake indicated that there was an important interaction between the two variables (d.f. = 3, F = 4.5, p = 0.023).

[Fluoride content of table salt in Mexico City]. / Flúor contenido en la sal para consumo humano distribuida en la ciudad de México.

The fluoride content of a sample of bags of salt for sale in Mexico City was measured in order to estimate the proportion of marketed salt that contained the quantity of fluoride set by the National Program for Prevention of Dental Caries through Consumption of Fluoridated Table Salt. The effectiveness of that program had never been evaluated. In March 1993, bags of salt were obtained from 70 of the 3544 neighborhoods that make up Mexico City. The stores were selected by simple random sampling. Salt was likewise purchased from 20% of the 146 supermarkets and self-service stores in the city, also selected as a random sample. Then, blind measurement was done of the fluoride content of 221 bags of salt. The true content of this element was often found to be below the amount called for by the government. In addition, it did not coincide with the quantity indicated on the package label, which is a violation of the law.

[Soft drink consumption patterns in a Mexican population]. / Patrón de consumo de refrescos en una población mexicana.

To evaluate soft drink consumption patterns in the Mexican population, the authors conducted a survey among people over 10 years of age in Mexico City (september-october 1993). Also, pH levels of commonly available beverages were measured using standard laboratory techniques. Results indicated that each one of the 33 soft drink brands and 15 brands of juices and beverages available, had markedly acidic pH values (between 2.46 and 3.96). Out of the 2,008 respondents (55.3% male, 44.7% female; response rate, 90.1%), 1,657 (82.5%) admitted drinking soft drinks daily, while 351 (17.5%) said they did not drink this type of beverages. Even though high consumption was frequent in all age groups, self-reported consumption was partially associated to age, being higher in the younger groups. The mean number of soft drinks ingested per day was reported to be 1.7, SD 1.3, and 9.3 per week SD 9.9. Self-reported consumption appeared to be independent of schooling level. Even though the largest proportion of non-consumers was found in the group that considered soft drinks to be a very important contributing factor to caries development, most interviewees agreed that soft drinks consumption was an important cariogenic factor. This attributed role was more prominent among interviewees with a higher level of schooling.