Fibre-reinforced composite (FRC) bridge--a minimally destructive approach.

Replacing missing teeth is an integral part of the clinical services of the dental practitioner. The fibre-reinforced composite (FRC) bridge is a relatively new method for replacing missing teeth. This article will explain and discuss this alternative treatment option. Practical instructions on how to construct a FRC bridge will be given, by means of a clinical case. Different technique options will be illustrated to provide the reader with a good understanding of the most practical way to use the FRC strips. The fibre-reinforced composite provides a non-destructive, aesthetically pleasing and cost-effective way to restore missing teeth. Clinical Relevance: Minimally invasive options should always be considered and destruction of healthy enamel and dentine during the preparation phase of a replacement treatment should be avoided as much as possible.

Fibre reinforced composites--alternative for lost teeth replacement.

The loss of an anterior tooth can affect a patient psychologically and socially. This trauma can be minimized by the immediate replacement of the lost tooth, preferably using a fixed prosthesis. This paper describes the immediate replacement of anterior lost teeth by using fibre reinforced composite materials, although these techniques can be employed very successfully in the replacement of posterior teeth as well. The abutment teeth can be conserved, with little or no preparation, making this procedure truly minimally invasive and keeping the technique reversible. Additional advantages are that the procedure is completed at the chairside in a single visit, thereby avoiding laboratory costs and saving time while waiting for the finished prosthesis. This technique can be used as an interim measure or as a permanent prosthesis.

Electrophoretic separation of canine haemoglobin in dogs with babesiosis.

Venous blood was collected from clinically healthy (n = 5) and B. canis (n = 5) infected dogs. Parasitised red blood cells were not removed from blood samples prior to preparation. The erythrocytes were washed, lysed, the haem ring removed from the haemoglobin molecule and the globin chains denatured by breaking disulphide linkages between amino acids. These haemolysates were then subjected to electrophoresis in polyacrylamide gels containing acid, urea and the non-ionic detergent Triton X-100. In all 5 B. canis infected dogs a protein band was observed above the beta chain of haemoglobin. This band was absent in all 5 healthy dogs. It is postulated that this band represents a fragment of the globin chain that remains after proteolysis caused by the B. canis parasite. Further study is needed to exclude the possibility that the electrophoretic band might be of parasitic origin.

Optimization of photopolymerized bioerodible hydrogel properties for adhesion prevention.

The aim of this study was to optimize the properties of a lubricious bioerodible hydrogel barrier for the prevention of postoperative adhesions. Water-soluble macromers based on block copolymers of poly(ethylene glycol) (PEG) and poly(lactic acid) or poly(glycolic acid) with terminal acrylate groups were used, and these macromers were gelled in vivo by exposure to long wavelength ultraviolet light. The precursor was photopolymerized from buffered saline solution while in contact with the tissues. This resulted in the conformal coating of the tissue with an adherent hydrogel film, while forming a nonadhesive barrier at the free surface, on the treated wound site. The hydrogels were evaluated in two animal models of postsurgical adhesions, first in a rat cecum abrasion model and then in a rabbit uterine horn ischemia model. In the rat cecum model, six of seven animals treated with a hydrogel, with glycolide in the precursor as the comonomer, showed no adhesions; untreated animals and animals treated with precursor, but not gelled with light, showed consistent dense adhesions. In the rabbit uterine horn ischemia model, using hydrogels with lactide in the precursor as the comonomer, and PEG of molecular weight from 6,000 to 18,500 Da, adhesions were dramatically reduced, with occurrence in none of seven animals treated with a gel containing PEG 10,000. By contrast, the seven animals in the control group demonstrated a mean of 35% involvement of the horn length in dense, fibrous adhesions. These materials, photopolymerized in vivo in direct contact with the tissues, appear to form an adherent hydrogel barrier that is highly effective in reducing postoperative adhesions in the models used.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparative study on the diagnostic sensitivity of rodent sperm and embryos in the detection of endotoxin in Earle's balanced salt solution.

PURPOSE: The bioassay used by most IVF units to assess culture media is the mouse embryo test. The limitations of this assay are well known. The objective of this study was therefore to evaluate the in vitro bioassay potential of rodent sperm, in terms of relative sensitivities to endotoxins, and to compare the results with the routine mouse embryo and human sperm tests. RESULTS: The greater sensitivity of rodent sperm than of mouse embryos was evident in this study. A further advantage in using the mouse sperm test was the time (4-6 hr) in which endotoxins could be detected. CONCLUSION: This rapid sperm test proved to be inexpensive, convenient, and invaluable for detecting potential sources of cytotoxicity.

Blood biochemical parameters and meat pH of feedlot cattle slaughtered on arrival or after overnight rest at an abattoir.

The effect of different pre-slaughter rest periods at the abattoir before slaughter on the blood biochemical parameters and meat pH of a number of cattle were studied on 2 occasions, once in summer and once in winter. In the first trial, 42 out of a consignment of 50 and in the second trial, 45 out of a consignment of 54 feedlot-finished oxen were randomly selected and divided into 3 groups each. One group was slaughtered on arrival at the abattoir, a second group 3 h after arrival and the third group was rested in the lairage prior to slaughter the following day. Carcasses were subjected to low voltage electrical stimulation at slaughter. Significant differences between the values obtained at the feedlot and those at the abattoir were found in respect of haematocrit, total plasma protein concentration, plasma glucose, plasma creatine kinase, plasma lipid and cortisol concentration in both the trials. In general, however, no great differences were found between the 3 groups in either of the trials. If any, results in respect of some of the blood parameters were in favour of the groups slaughtered as soon as possible after arrival at the abattoir. No significant differences were found in the initial (35-45 min) and ultimate (24 h) pH of the meat between the 6 groups of slaughtered animals in the 2 trials. Exsanguination appeared to be satisfactory in all groups and no differences between groups were found. It was concluded that feedlot cattle transported to an abattoir over a relatively short distance, need not necessarily be rested in the lairage overnight before slaughter.

Oxytetracycline plasma concentrations in sheep after the administration of a polyvinylpyrrolidone formulation.

A polyvinylpyrrolidone formulation of oxytetracycline was injected intramuscularly into 5 sheep at 2 different dosages of 10 mg and 20 mg/kg body mass respectively. Plasma levels were determined. The higher dosage not only attained a higher peak value, but the concentration at 12 hours was 0.5 micrograms/ml. At the lower dosage rate a level of 0,63 micrograms/ml was recorded 32 hours after administration when that of the higher dosage rate was 1,5 micrograms/ml.

Relation between macrophage migration inhibition and immunity to Brucella abortus in guinea-pigs.

Relation between macrophage migration inhibition and immunity to Brucella abortus in guinea-pigs. Onderstepoort Journal of Veterinary Research 43 (4), 175-184 (1976). A soluble protein antigen was prepared from Brucella melitensis Rev I with which macrophage migration inhibition (MMI) assays were successfully done using guinea-pig peritoneal exudate cells. By comparing the MMI, agglutinin response and immunity of groups and of individual guinea-pigs which had been immunized with either B. melitensis Rev I live vaccine or B. melitensis Rev I inactivated antigen, an association between the MMI and resistance to infection was demonstrated.

Inhibition of macrophage migration in Salmonella immunity.

Protein antigens were prepared from rough strains of Salmonella typhimurium and S. dublin by phenol and veronal-buffer extraction. It was shown that the in vitro migration of peritoneal exudate cells from guinea pigs that were immunized with rough avirulent mutants could be inhibited effectively with these antigens. The cells obtained from S. typhimurium-immunized guinea pigs were also sensitive to S. dublin antigens and vice versa. A degree of sensitivity and inhibition could be demonstrated consistently in a group of immunized guinea pigs. However, the variation in samples, even from among individual animals that had survived challenge, was so great that it precludes the use of the macrophage migration technique as a routine standard assay procedure for immunity.