Acute toxicity (LD50 and CD50) of lidocaine and prilocaine in combination with adrenaline and felypressin.

The toxicity of the combination of vasoconstrictors to local anaesthetic solutions has been debated since its first use in the beginning of this century. A combination of two vasoconstrictors to a local anaesthetic has been proposed by some researchers. In this study they were evaluated the acute toxicity (lethal dose 50%, convulsion dose 50%) and latency times of loss of righting reflex and convulsion as well as the duration of convulsion) of 2% lidocaine or 3% prilocaine, when administered in combination with adrenaline and felypressin at various concentrations. Lethal dose 50% studies showed that for both anaesthetics the solutions with higher concentrations of adrenaline were more toxic. The opposite was observed in the convulsion dose 50% studies. No alterations were observed in the control groups. All lidocaine solutions increased the latency of loss of righting reflex. The latency of convulsion was increased in some groups, but once the convulsion was achieved there was no difference in its duration. There was no statistical difference among prilocaine groups for any of the variables studied. Based on the experimental model studied, it was concluded that there is no advantage in the association of two vasoconstrictors concerning the toxicity of lidocaine and prilocaine solutions.

Cariogenic [correction of Carcinogenic] potential of a typical cassava flour from the Amazonian region of Brazil.

The purpose of this study was to compare the cariogenic potential of a typical cassava flour (CF) with sucrose and starch, using a severe cariogenic challenge model in rats. Thirty Wistar female pups with their dams (mutans streptococci free) were infected by Streptococcus sobrinus 6715, desalivated when aged 25 days, and placed in a Konig-Hofer programmed feeder at age 26 days. They received 17 meals daily at hourly intervals for 21 days as follows: group (1) powdered plain sucrose and sterile distilled water ad libitum (sdwal); (2) Lf and Sdwal (3) powdered starch and sdwal. Essential nutrition was administered by gavage. Data were analyzed by ANOVA. The percentage of S. Sobrinus related to the total flora and the number of this microorganism were higher in the sucrose and CF groups than starch group. Smooth-surface and [sulcal] caries scores for the groups were: (1) 105.5 [48.0]; (2) 34.1 [39.2]; (3) 10.2 [18.1]. All the groups were statistically significantly different from each other (p < 0.01), although the result for sulcal score for CF was very close to the sucrose group. It is concluded that cassava flour, the main source of carbohydrate for the Amazonian population of Brazil, has moderate cariogenic potential.