Root Caries Preventive Effect of Varnishes Containing Fluoride or Fluoride + Chlorhexidine/Cetylpyridinium Chloride In Vitro

Caries preventive varnishes containing only fluoride might differ from those containing a combination of fluoride and antimicrobial components in terms of mineralization properties and their impact on the cariogenic biofilm. We compared a fluoride and a fluoride + chlorhexidine (CHX)/cetylpyridinium chloride (CPC) varnish on root caries formation in vitro. One hundred bovine root dentin samples were allocated to five groups (n = 20/group): (1) 7700 ppm fluoride varnish (Fluorprotector S (F)), (2) experimental placebo varnish for F (F-P), (3) 1400 ppm fluoride + 0.3% CHX/0.5% CPC varnish (Cervitec F (CF)), (4) experimental placebo varnish for CF (CF-P), (5) untreated control. Cariogenic challenge was provided using a multi-station, continuous-culture 3-species (Streptococcus mutans (SM), Lactobacillus rhamnosus (LR), Actinomyces naeslundii (AN)) biofilm model for 10 days. Mineral loss (ΔZ) was evaluated using transversal microradiography and bacterial counts in the biofilm assessed as colony-forming units. Fluorescence in situ hybridization (FISH) and confocal microscopy were performed to assess the three-dimensional biofilm architecture. Mean ± SD (vol% × μm) ΔZ was significantly lower for F (9133 ± 758) and CF (9835 ± 1677) compared to control (11362 ± 919) (p < 0.05), without significant differences between F and CF. SM counts were significantly lower and LR counts significantly higher in F- and CF-biofilms compared to control. AN counts were significantly higher in the F-biofilms than in all other groups. According to FISH, SM and LR invaded dentinal tubules only in the control-group. In the CF-group, the basal biofilm layer did not contain SM and AN. Both F and CF varnishes had similar caries-preventive effects and a considerable impact on biofilm structure and composition.

Influence of anesthetic induction with halothane and isoflurane on internal carotid blood flow velocity in early infancy

In contrast to adult humans and animals, so far there are no studies in infancy on the effects of halothane and isoflurane on cerebral hemodynamics. We used transfontanellar Doppler ultrasonography to close this gap. In the study we looked at changes of Vmax as a measure of changes in cerebral blood flow. In 10 infants (4.7 +/- 1.0 kg BW) Vmax decreased 5 min after anesthetic induction with halothane 1.5% at 33%, and in a comparable group of 10 infants (5.3 +/- 1.2 kg BW) 5 min after anesthetic induction with an equipotential dose of isoflurane 2.5% at 28%. In 4 infants there was even a retrograde diastolic flow under anesthetic induction. This decrease was so far never seen in adults, in whom halothane increases cerebral blood flow and isoflurane has only little effect.