pH-cycling is more appropriated to simulate a substrate that resembles affected caries dentine layer, after caries removal. The microbiological method seems more indicated to simulate a dentine caries lesion with an infected layer, previously to caries removal.

BaCKGROUND. The prevalence of dental erosion seems to be rising in young populations, particularly among individuals of higher socioeconomic status. AIM. To assess the prevalence and associated factors of dental erosion in children and adolescents of a private dental practice. DESIGN. A total of 232 participants, aged 2-20 years, were examined. Dietary habits, oral hygiene, and medical data were collected from dental records. Logistic regression analyses were conducted. RESULTS. Dental erosion prevalence was of 25.43% and was highest on the occlusal surfaces (76%). Associated factors were: frequent consumption of soft drinks (OR = 2.33; 95% CI = 1.01-5.38) and candies (OR = 3.23; 95% CI = 1.25-8.32); and interaction between these two factors (OR = 3.95; 95% CI = 1.60-9.75). On anterior teeth, associated factors were: frequent consumption of fruits (OR = 2.53; 95% CI = 1.09-5.91); and age (OR = 1.07 95% CI = 1.01-1.14). Milk consumption was associated with a lower prevalence of dental erosion (OR = 0.40; 95% CI = 0.17-0.94). CONCLUSIONS.  A relatively high prevalence of erosion was found in association with frequent intake of soft drinks, candies, and fruits. The consumption of milk seemed to protect against dental erosion on anterior teeth.

Cancer is the third most frequent cause of death in children in Brazil. Early diagnosis and medical advances have significantly improved treatment outcomes, which has resulted in higher survival rates and the management of late side effects has become increasingly important in caring for these patients. Dental abnormalities are commonly observed as late effects of antineoplastic therapy in the oral cavity. The incidence and severity of the dental abnormalities depend on the child's age at diagnosis and the type of chemotherapeutic agent used, as well as the irradiation dose and area. The treatment duration and aggressivity should also be considered. Disturbances in dental development are characterized by changes in shape, number and root development. Enamel anomalies, such as discoloration, opacities and hypoplasia are also observed in these patients. When severe, these abnormalities can cause functional and esthetic sequelae that have an impact on the children's and adolescents' quality of life. General dentists and pediatric dentists should understand these dental abnormalities and how to identify them aiming for early diagnosis and appropriate treatment.

The purpose of the present study was to evaluate the erosive potential of different types (concentrated and powdered) and commercial brands of industrialised grape juices. The pH of all five fruit drinks was measured at two time points: immediately after preparation and 24 hours later. Sixty specimens of bovine enamel were randomly allocated and immersed in different types of grape juice (n = 10) for 10 minutes four times a day for fifteen days. The enamel alteration was analysed using surface Knoop microhardness (KHN) and surface roughness (R a ) tests at baseline and on the 5 th , 10 th and 15 th days of the experiment. Two way ANOVA, Tukey's post hoc and Pearson's correlation tests were used for statistical analysis (α = 5%). The grape juices presented pH values ranging from 2.9 to 3.5. All of the tested juices promoted significant enamel mineral loss (p < 0.05) on the first evaluation (5 th day of immersion) and produced a significant increase in the mean roughness from the 10 th day on when compared to the control group (p < 0.05). By the 15 th day, all of the beverages had produced surface roughnesses that were significantly higher than that of the control group. The results suggest that all grape juices, regardless of their commercial presentation, present erosive potential.