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Biomedical subjects

L Fabricius

Publications and source records attributed to L Fabricius.

7 recordsLinked to original sources
PubMed1982

Influence of combinations of oral bacteria on periapical tissues of monkeys.

The present study deals with the ability of 11 bacterial strains, in various combinations, to induce periapical reactions. The indigenous oral bacteria were originally isolated from an experimental apical periodontitis in monkey. Eight of the strains were complete collection isolated from one root canal. These strains were inoculated together, in equal proportions, into 12 root canals. In addition, 63 canals were inoculated with other combination or separate strains. At the end of the experimental period it was found that in the mixed infections the Bacteroides oralis strain predominated in most root canals. In contrast, this Bacteroides strain was not reisolated in any of nine root canals when inoculated in a pure culture. Enterococci, however, survived as pure cultures in all canals. The mixed infections showed the greatest capacity of inducing apical periodontitis, as revealed by radiography, and most pronounced was the "eight-strain collection". The facultatively anaerobic streptococci induced only weak periapical reactions.

Animals↗
PubMed1982

Apical periodontitis induced by selected bacterial strains in root canals of immunized and nonimmunized monkeys.

Experimental infections in root canals with Streptococcus faecalis ss. liquefaciens (Strep-MC4). Actinomyces bovis (Act-MC6) and Bacteroides oralis (Bact-MC3) were studied in four immunized and five nonimmunized monkeys. The immunization was performed using antigens of the homologous strains. The antibody level was checked by gel diffusion. In 56 root canals of the immunized animals and 60 root canals of the nonimmunized animals, viable cells of the three bacterial strains were enclosed in equal amounts of various combinations. After 6 months, samples from the root canals were subjected to qualitative and quantitative bacteriologic analyses and the apical area was radiographically and histologically examined. The analyses revealed no significant difference between the two groups of monkeys, although the viable cell recovery was slightly higher in most of the root canals of nonimmunized monkeys. The cell proportion of the strains within the different bacterial combinations was equal in root canals of the two groups of animals. The radiographic and histologic examinations revealed no significant difference between the two groups of animals regarding the number of teeth with periapical lesions. The radiographic examination, however, showed a more distinct limitation of the process in the immunized than in the nonimmunized monkeys. Histologically the lesions were more encapsulated and had a sparser cell infiltration in immunized than in nonimmunized monkeys. In the latter, inflammatory cells had often infiltrated the bone. Mixed infections gave a more severe periapical reaction than single strain infections in both animal groups.

Actinomyces↗
PubMed1982

Circulating antibodies after experimental chronic infection in the root canal of teeth in monkeys.

Root canals of 49 teeth with necrotic pulp tissue in five monkeys were infected with Streptococcus faecalis ss liquefaciens, Actinomyces bovis, Fusobacterium nucleatum, Peptostreptococcus anaerobius, and Bacteroides oralis in various combinations. After 6 months the root canals and the periapical tissues were subjected to radiographic, bacteriologic, and histologic examinations. Signs of periapical inflammation were radiographically registered in 41 teeth, most frequently in teeth inoculated with a mixed flora. In 11 out of 16 teeth infected separately with Strep. faecalis ss liquefaciens, apical periodontitis was observed. Sera from the monkeys prior to and after the experimental inoculation were analyzed by means of gel diffusion, hemagglutination (HA), and complement binding test for antibodies against different antigen preparations of the homologous bacterial strains used for the inoculation. Detectable antibodies were seen with antigens of B. oralis in all five monkeys. Agglutinating antibodies were demonstrated with lipopolysaccharide-antigen of B. oralis in titers between 1:40 and 1:320. A marked reduction of the antibody level against lipopolysaccharide (LPS) antigen after mercaptoethanol treatment indicated that a main part of the antibodies registered was of IgM-class. The study shows that certain antigens of bacterial origin from infected root canals, while affecting the periapical tissues, also stimulate the production of circulating antibodies.

Animals↗
PubMed1982

Predominant indigenous oral bacteria isolated from infected root canals after varied times of closure.

The pulps of 24 root canals, eight in each of the three monkeys, were mechanically devitalized and exposed to the mouth flora for about 1 week and thereafter sealed. Microbiologic sampling and analysis was performed in 16 teeth (two of the monkeys) after 7 d of closure (initial samples). The teeth of the three monkeys represented observation times of 90, 180 and 1060 d. At the end of each observation period final samples were taken. Final sampling included samples from the main root canal, the dentin, and the apical region at the same sampling session. All microbiologic analyses were carried out quantitatively. Final root canal samples from the apical region showed a predominance of obligately anaerobic non-sporulating bacteria, in fact 85-98% of the bacterial cells were anaerobic. The most frequently found species were Bacteroides and Gram-positive anaerobic rods. A lower proportion of facultatively anaerobic bacteria was found. This was most pronounced for coliform rods in comparison with strains of B. melaninogenicus.

Animals↗
PubMed1981

Influence on periapical tissues of indigenous oral bacteria and necrotic pulp tissue in monkeys.

In nine monkeys (Macaca fascicularis) the pulps of 78 teeth were aseptically necrotized. Twenty-six of the pulp chambers were kept bacteria-free by sealing, while 52 were infected by the indigenous oral flora. The results were recorded clinically, radiographically and microbiologically at the beginning of the experiment and after 6-7 months. The final examination also included histologic recordings. The initially noninfected root canals were all sterile at the final samplings, indicating that the risk of contamination (including hematogenous) of root canals of this animal is very slight. It was shown that noninfected necrotic pulp tissue did not induce inflammatory reactions in the apical tissues. By contrast, teeth with infected pulp tissue showed inflammatory reactions clinically (12/52 teeth) and radiographically (47/52 teeth). Facultatively anaerobic streptococci, coliform rods and obligately anaerobic bacterial strains were most frequently found. In the final samples the number of obligately anaerobic strains increased. Some microorganisms which were isolated in the initial samples were not detected in the final samples. All infected teeth histologically examined showed strong inflammatory reactions in the periapical region.

Animals↗