Short-term effect of ice-cream containing Bifidobacterium lactis Bb-12 on the number of salivary mutans streptococci and lactobacilli.

OBJECTIVE: Probiotic bacteria are thought to reduce the risk of some infectious diseases. The aim of the present study was to examine whether or not short-term consumption of ice-cream containing bifidobacteria can affect the salivary levels of mutans streptococci and lactobacilli in young adults. MATERIAL AND METHODS: A double-blind, randomized crossover study was performed and 24 healthy subjects (mean age 20 years) were followed over 4 periods. During periods 2 and 4 (10 days each), they ingested 100 ml (53 g) ice-cream containing Bifidobacterium lactis Bb-12 once daily or a control ice-cream without viable bacteria. Periods 1 and 3 were run-in and washout periods, respectively. Salivary mutans streptococci and lactobacilli were enumerated with chair-side kits at baseline and immediately after the intervention period. RESULTS: A statistically significant reduction (p<0.05) of salivary mutans streptococci was recorded after consumption of the probiotic ice-cream. A decline of high mutans streptococci counts was also seen after intake of the control ice-cream, but the difference compared to baseline was not statistically significant. The salivary lactobacilli levels were unaltered after both regimes. CONCLUSIONS: Daily consumtion of ice-cream containing probiotic bifidobacteria may reduce the salivary levels of mutans streptococci in young adults.

Compressive strength, surface roughness, fluoride release and recharge of four new fluoride-releasing fissure sealants.

The aim of this study was to investigate the compressive strength and surface roughness of two glass ionomer cements and two resin-based fissure sealants before and after fluoride release and recharge. Twenty-one specimens were prepared and divided into three groups for each material. First group was loaded in compression until failure. Fluoride released was measured from the remaining specimens, and then the second group of seven specimens was loaded at 28th day. The remaining seven specimens were exposed to 0.05% NaF solution and 1.23% APF gel. Fluoride amount was measured, and the last group was loaded at 70th day. Surface roughness measurement of five more disk-shaped specimens from each material was also carried out. After exposure to APF gel, all materials were recharged. At the end of experimental period, it was found that surface roughness increased, whereas compressive strength decreased, over time. In conclusion, fluoride-releasing fissure sealants could act as show, rechargeable fluoride release systems. However, if a fissure sealant exhibited high fluoride release, it had inferior mechanical properties.