Relationship between plaque pH and different caries-associated variables in a group of adolescents with varying caries prevalence.

The pH response of the dental biofilm after a sugar challenge can be considered to mirror the acidogenic potential and thereby the caries risk of an individual. The aim of this cross-sectional study was to evaluate the relationship between plaque pH and different caries variables in adolescents with varying caries prevalence. One hundred individuals, aged 14-15 years, were examined regarding different caries-related variables: (i) caries score (DSm, DSi, DSm + i, DTm), (ii) salivary secretion rate and buffer capacity, (iii) oral microflora of plaque and saliva, (iv) plaque amount, (v) plaque pH and (vi) dietary intake, oral hygiene habits and fluoride use. Plaque pH was assessed using the microtouch method before and after a 1-min mouthrinse with 10 ml 10% sucrose. Depending on the minimum pH, the participants were divided into three groups: low pH (≤5.3), medium pH (>5.3-6.3) and high pH (>6.3). Statistically significant differences between the three groups (p < 0.01) were found for initial caries (DSi) and combined manifest and initial caries (DSm + i). A statistically significant difference was also found in the log values for salivary lactobacilli (p = 0.02) within the three groups, and for the total number of bacteria in plaque (p = 0.04); for both variables, the low-pH group had the highest values. The only covariate significantly associated was the Cariogram score in the medium-pH group (p < 0.01) and the number of meals per day in the high-pH group (p = 0.02). To conclude, plaque pH measured by the microtouch method is a method that can be used for discriminating between individuals with varying caries prevalence.

Diffusion-weighted imaging in fetuses with unilateral cortical malformations and callosal agenesis.

DWI was performed in fetuses with callosal agenesis and unilateral cortical malformations. ADC values were retrospectively measured in the developing white matter underlying the cortical malformation and compared with the corresponding contralateral white matter. In all 3 patients, ADC values were lower under the areas of cortical malformation compared with the normal contralateral side. Our findings suggest that there are structural differences in the developing white matter underlying areas of cortical malformation.

Influence of short-term sucrose exposure on plaque acidogenicity and cariogenic microflora in individuals with different levels of mutans streptococci.

The aim was to study the short-term effect of a varying sucrose exposure on plaque acidogenicity and cariogenic microflora in two groups of subjects with different levels of mutans streptococci (MS). Eight subjects with low (<10(4)) and 8 with high (>10(6)) numbers of MS per millilitre saliva participated. Three 7-day test periods were conducted. During two of these, the subjects rinsed either 5 or 10 times daily with 10% sucrose; the third period without any mouth rinses served as control. The subjects refrained from oral hygiene during the last 3 days of each test period. On day 7, the following parameters were measured: plaque pH after a sucrose rinse, numbers of MS, Streptococcus sanguis and lactobacilli in saliva, percent MS in plaque and plaque index. The results revealed that plaque acidogenicity was more pronounced for the high-MS group compared to the low-MS group after all three test periods, i.e. lower resting pH, deeper pH falls and a lower final pH. For both groups, the greatest pH-lowering capacity of plaque was found after the period with 10 sucrose rinses/day. An increase in bacterial counts was noted for both groups during the test periods with the 5- and 10-time rinse regimen; this increase was larger for the high-MS group compared to the group with low MS counts. The highest plaque index was, irrespective of the test period, found for the high-MS group.