Carbohydrate metabolism of Streptococcus mutans in dental plaque in gnotobiotic rats.

The fermentation products of Streptococcus mutans C67-1 were investigated in fissure plaque of rats, that were mono-associated with this strain. In addition to lactic acid, acetic acid and ethanol were present. The finding that a mixed acid fermentation occurred and that ethanol was produced suggests that the carbohydrate source rather than the nitrogen source was the growth-limiting substrate for Strep. mutans in plaque.     

Clinical study of an amine fluoride gel and acidulated phosphate fluoride gel

Abstract This study compared caries inhibition in children by an amine fluoride and an acidulated phosphate fluoride when administered in a topically applied gel. In addition, the effects of applying amine fluoride daily and weekly were compared. Four hundred and sixty-eight children, ages 6 to 13, were randomly assigned to one of five treatment groups and received a total of five, 5-minute treatments. The treatment and interval between each of the five treatments were as follows: (A) acidulated phosphate fluoride daily, (B) amine fluoride daily, (C) amine fluoride weekly, (D) placebo daily, and (E) placebo weekly. When the children were examined for total Decayed, Missing, and Filled Surfaces (DMFS) increments 2 years later, no significant differences were observed. However, when the data were examined for effects on DMFS for a specific tooth surface, significant restriction (61 %) of occlusal increment was shown in the group which was treated with amine fluoride daily for 5 consecutive days as compared with the control group.     

Two-way cross-reactions between serotypes of Actinomyces viscosus.

Three antigen preparations were obtained from cultures of A. viscosus Serotypes 1 and 2. Ammonium sulphate (60 per cent w/v) and acetone precipitates were obtained from cellfree culture supernatants of late-log phase cultures of each organism. The third preparation consisted of the supernatant obtained after homogenization of late-log phase cells of each organism. Immunodiffusion and immunoelectrophoresis using rabbit antisera to each serotype were used to identify the soluble antigens present in each preparation. Ammonium sulphate preparations proved to be the most reproducible and contained the greatest number of identifiable antigens. Homologous and cross-reacting antigens were identified and two-way cross-reactions were observed between the serotypes.     

Matches,clips, needles,or pins

Several methods for positioning dowel pins used in the fabrication of removable dies have been presented. Needles, pins, paper clips, hairpins, and matches are all useful in positioning dowel pins in the impression. The use of paper matches is a simple and effective method for holding the dowel pin in the proper relation while the die stone portion of the cast is being poured.     

Althesin for dental anaesthesia in children. A comparison with methohexitone sodium

The new steroid intravenous anaesthetic agent Althesin was compared with methohexitone sodium for out-patient dental extractions in children. No serious disadvantages in its use were found. The small volume required and lack of irritant properties on injection were considered to be advantageous in this age-group.     

The biochemical growth and development of the palate, maxilla, mandible and tongue in the New Zealand white rabbit

Seventy-two female New Zealand white rabbits were divided into six groups and killed with Nembutal at 17.0, 17.5, 18.0, 18.5, 19.0 and 19.5 days postconception. The foetuses were removed; the palates, maxilla, mandibles and tongues were dissected from each foetus, weighed and pooled; DNA, RNA and protein were determined in each pooled sample. The results showed three distinct patterns of development. The mandible and maxilla showed similar developmental patterns, while the palate and tongue each showed their own distinct pattern. The palate showed a remarkable rise in protein/DNA at day 18.0, the time corresponding to palatal closure in our rabbits. Further such studies may elucidate the role that relative growth rates of these tissues plays in the aetiology of cleft palate.