An in vitro assessment of fluoride uptake by tooth enamel from four different fluoride dentifrices.

AIM: The aim of this study was to evaluate fluoride uptake by tooth enamel with four different fluoride dentifrices. STUDY DESIGN: Sixty human premolars extracted for orthodontic purpose were selected for the study. The teeth were covered with nail varnish leaving a window of 4 × 4 mm on the enamel surface of the buccal and lingual sides. The teeth were demineralised and were divided into four groups with 15 teeth in each group. The buccal window served as experimental and the lingual as control. The teeth were immersed in toothpaste slurry containing: sodium fluoride (Group A); sodium monofluorophosphate (Group B); stannous fluoride (Group C) and amine fluoride (Group D). The fluoride content in the etched superficial enamel layer in the windows was analysed using a fluoride ion-specific electrode. RESULTS: Within the parameters of this study, the uptake of fluoride was statistically significant in Group D (p < 0.05). The uptake of fluoride by tooth enamel in an increasing order was Group A < Group B < Group C < Group D. CONCLUSION: The study showed that enamel treated with amine fluoride had the highest fluoride uptake.

Fertility on synchronized estrus in crossbred (Bos taurus x Bos indicus) heifers.

This study was performed in Western Maharastra (India). The 272 crossbred heifers were randomly allocated within herds to one of the four following groups: 1) silastic coils, 10 days treatment (n = 65); 2) Norgestomet implants, 10 days treatment (n = 71); 3) prostaglandin F(2alpha) two injections 11 days apart (n = 70); and 4) control (n = 66). Almost all heifers in the treated groups were detected in heat during the four days following treatment (88-100%) vs 26% in the control group in the first 21 days. Mean conception rates at first AIs were respectively 62,48 and 60% in groups 1,2 and 4 (p > 0.05) and only 29% in group 3. By 90 days after treatment, 66, 59, 46 and 33 per cent of the females were pregnant for groups 1 to 4, respectively (p < 0.001). In conclusion, progestogen treatments seemed to be highly satisfactory both in terms of conception rates and intervals from treatment to pregnancy.