The effects of putrefaction on haptoglobin phenotyping from tooth fragments.

Tooth fragments freshly extracted from humans were stored for various times and temperatures under both dry and moist conditions. The fragments were reduced to powder and proteins eluted. Purified haptoglobin fractions were separated, detected and phenotyped using the Phast Gel electrophoresis system using gradient gels. Haptoglobin phenotypes were demonstrable but became less detectable as time increased.

The effect of conditions of putrefaction on species determination in human and animal teeth.

Tooth fragments freshly extracted from humans and rats were stored at either 4 degrees C or room temperature in dry or humid conditions for periods ranging from 1 to 6 months. The fragments were reduced to powder and antigens were extracted. Comparison of these samples was carried out using Counter Current Electrophoresis. Extracted sera were tested against known specific antisera and resultant precipitin reactions stained for examination. Correct species identification was possible both from desiccated and humid fragments but there was species variation in the sensitivity of the method. All the extracts from human teeth were positive against human antisera. In the rat some test specimens were initially negative but became positive following further dilution of the extracts.

Antimicrobial properties of 2 aliphatic amines and chlorhexidine in vitro and in saliva.

The surfactants tetradecylamine, hexadecylamine and chlorhexidine have been compared with regard to their ability to inhibit microbial growth. Antibacterial activity was assessed by tube dilution methods. Tetradecylamine and chlorhexidine were similar in antibacterial activity, being effective at low concentrations against most organisms tested. Hexadecylamine also inhibited growth but at higher concentrations. Viable counts of salivary organisms were monitored in volunteers over 48 h after one rinse with the agents. The initial reduction in numbers of total viable salivary bacteria and streptococci by tetradecylamine and of streptococci by hexadecylamine had disappeared 3 h after a single mouth rinse, but the reduction in numbers of all salivary bacteria by chlorhexidine was more prolonged.

Simple bacteriological methods to assess changes in subgingival microflora produced by metronidazole-containing acrylic strips placed into periodontal pockets.

Dark field microscopy is perhaps the simplest microbiological technique to monitor the effects of treatment methods on bacterial plaque. However, the method provides qualitative rather than true quantitative data. This study attempts to measure changes in flora by a number of methods following the placement of 40% metronidazole acrylic strips into periodontal pockets. 10 patients with periodontal pockets greater than 6 mm which bled on probing had acrylic strips placed for 2 to 3 days. Prior to insertion and after removal, subgingival plaque samples were collected into 1 ml of saline and processed as follows. (a) Dark field microscopy for qualitative shifts. (b) Gram stain for differential counts. (c) Counting chamber for total counts. (d) Serial dilution and culture for total cultivable counts. After treatment the significant changes were as follows. (a) % increase in cocci and decreases in other forms, particularly motile organisms. (b) Gram-positive cocci increased and Gram-negative bacilli decreased. (c) Total counts obtained by the sampling method decreased greater than 80%. (d) Total cultivable counts decreased greater than 75%. (e) The efficiency of culturing appeared low and the potential problems of sampling to quantification were identified. The consistency of the changes produced suggested that using simple bacteriological techniques it was possible to show marked changes in the numbers and types of organism present in subgingival plaque following the use of local antimicrobial therapy.

The development and in vitro evaluation of acrylic strips and dialysis tubing for local drug delivery.

This study reports on the development of drug containing acrylic strips for delivering antimicrobial agents and compares the in vitro release pattern with dialysis tubing. Polyethylmethacrylic strips of suitable dimensions containing 10 to 50% chlorhexidine acetate, 40% metronidazole and 40% tetracycline were prepared. Daily release of the incorporated drugs into 1 ml aliquots was measured spectrophotometrically over a 14 day period. Similarly the release of chlorhexidine gluconate from various lengths of patent and heat sealed dialysis tubing was recorded for 4 days. At 30%, 40% and 50% admixtures the acrylic strips released chlorhexidine up to the 14 day period and a parallel bioassay confirmed the maintenance of antibacterial activity to this time. At the same admixture the release of metronidazole was greater than chlorhexidine and tetracycline. All drugs were released at high levels on day 1 followed by a marked fall in release by day 2 and progressive fall thereafter. The release from tubing was almost total within 24 hours and was independent of sealing the ends. The strips appear to have potential for prolonged drug delivery to periodontal pockets. Preliminary clinical use revealed no patient acceptability problems and alterations in subgingival flora were produced.