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The purpose of this study was twofold: first, to determine the influence on the healing of the periapical tissues when selected bacterial strains and combinations thereof remain after root canal treatment; and, second, the relationship to healing of the quality of the root filling. In eight monkeys, 175 root canals, previously infected with combinations of four or five bacterial strains and with radiographically verified apical periodontitis, were endodontically treated, bacteriologically controlled, and permanently obturated. After 2-2.5 yr, the periapical regions were radiographically and histologically examined. Of these teeth, 48 root canals were also examined for bacteria remaining after removal of the root fillings. When bacteria remained after the endodontic treatment, 79% of the root canals showed non-healed periapical lesions, compared with 28% where no bacteria were found. Combinations of residual bacterial species were more frequently related to non-healed lesions than were single strains. When no bacteria remained, healing occurred independently of the quality of the root filling. In contrast, when bacteria remained, there was a greater correlation with non-healing in poor-quality root fillings than in technically well-performed fillings. In root canals where bacteria were found after removal of the root filling, 97% had not healed, compared with 18% for those root canals with no bacteria detected. The present study demonstrates the importance of obtaining a bacteria-free root canal system before permanent root filling in order to achieve optimal healing conditions for the periapical tissues.

The purpose of this study was twofold: first, to determine the influence on the healing of the periapical tissues when selected bacterial strains and combinations thereof remain after root canal treatment; and, second, the relationship to healing of the quality of the root filling. In eight monkeys, 175 root canals, previously infected with combinations of four or five bacterial strains and with radiographically verified apical periodontitis, were endodontically treated, bacteriologically controlled, and permanently obturated. After 2-2.5 yr, the periapical regions were radiographically and histologically examined. Of these teeth, 48 root canals were also examined for bacteria remaining after removal of the root fillings. When bacteria remained after the endodontic treatment, 79% of the root canals showed non-healed periapical lesions, compared with 28% where no bacteria were found. Combinations of residual bacterial species were more frequently related to non-healed lesions than were single strains. When no bacteria remained, healing occurred independently of the quality of the root filling. In contrast, when bacteria remained, there was a greater correlation with non-healing in poor-quality root fillings than in technically well-performed fillings. In root canals where bacteria were found after removal of the root filling, 97% had not healed, compared with 18% for those root canals with no bacteria detected. The present study demonstrates the importance of obtaining a bacteria-free root canal system before permanent root filling in order to achieve optimal healing conditions for the periapical tissues.

The haematological characteristics of the African snakehead Parachanna obscura includes mean blood haemoglobin concentration of 5.70g/dl, mean haematocrit of 19.20%, mean red blood cell count of 1.67 x 10 12/L, mean total white blood cell count of 19.07 x 103 mm-3, mean erythrocytic haemoglobin concentration of 29.08%, mean erythrocytic haemoglobin of 39.86 g, mean erythrocytic volume of 132.84 μ3, mean total plasma protein of 4.45 g/dl and mean plasma glucose of 67.42 mg/dl. Correlations were found with certain blood parameters as function of the length, weight and condition factor..African Journal of Biotechnology Vol. 4 (6), pp. 527-530, 2005

The U.S. Bureau of Reclamation's Paradox Valley Unit (pvu) extracts aquifer brine from nine shallow wells along the Dolores River, Paradox Valley, in southwestern Colorado and, after treating, high pressure injects the brine 4.3–4.8 km below the surface. pvu injects at rates between ∼800 and ∼1300 L/min. Since 1991, pvu has emplaced over 4 × 106 m3 of fluid and induced more than 4000 surface-recorded seismic events. The events are recorded on the local 15-station Paradox Valley Seismic Network. The induced seismicity at Paradox separates into two distinct source zones: a principle zone (>95% of the events) asymmetrically surrounding the injection well to a maximum radial distance of ∼3 km, and a secondary, ellipsoidal zone, ∼2.5 km long and centered ∼8 km northwest of the injection well. The expansion of these zones has stabilized since mid-1999, about three years after the onset of continuous injection. Within the principal zone, hypocenters align in distinct linear patterns, showing at-depth stratigraphy and the local Wray Mesa fracture and fault system. The primary faults of the Wray Mesa system are aseismic, striking subparallel to the inferred maximum principal stress direction, with one or more faults, probably, acting as fluid conduits to the secondary seismic zone. Individual seismic events, in both zones, do not discernibly correlate with short-term injection parameters; however, a 0.5 km2 region immediately northwest of the injection well responds to long-term, large-scale changes in injection rate and the surpassing of a threshold injection pressure. Focal mechanisms of the induced events are consistent with simple double-couple, strike-slip moments and subhorizontal extension to the northeast. In addition, the fault planes are consistent with principal stress directions determined from borehole breakouts. More than 99.9% of the pvu seismicity is below human detection (∼M 2.5). However, approximately 15 events have been felt locally, with the largest being a magnitude M 4.3. Because of the M 4.3 and two earlier-felt M ∼3.5 events and injection economics, pvu changed injection strategies three times since 1996. These changes reduced seismicity from ∼1100 events/year to as low as ∼60 events/year.

In six monkeys, 160 root canals were inoculated with a combination of four bacterial strains belonging to species Streptococcus milleri, Peptostreptococcus anaerobius, Prevotella oralis, and Fusobacterium nucleatum. In two other monkeys, 24 root canals were inoculated with a five-strain combination consisting of these strains and a strain of Enterococcus faecalis. All strains were previously isolated from an infected monkey root canal. After 8-12 months, survival of the strains was recorded bacteriologically, and the reaction in the periapical region was radiographed. From 180 of 184 root canals, one or more of the bacterial strains were reisolated. The two facultative strains were more frequently reisolated than the anaerobic strains. Apical periodontitis was registered in the periapical region of more than 96% of root canals with reisolated bacteria but in none of those without reisolated bacteria. Endodontic treatment was carried out in two sessions with an interval of 14 d without interappointment dressings, and the effect was evaluated bacteriologically before and after each treatment. The chemo-mechanical treatment reduced significantly the number of strains and bacterial cells. The facultative bacteria were more resistant to the treatment than the anaerobic bacteria. The five-strain combination had a higher survival rate than the four-strain combination.

The prevalence and microbiology of macrophotographically documented denture stomatitis were studied in denture wearers participating in an interdisciplinary health-monitoring project (Koster Health Project) on the Koster islands, Sweden. Upper dentures were used by 26.6% of the adult population, and 59.2% of the denture wearers had stomatitis. Denture stomatitis type I was identified as sialadenitis. The more severe forms of denture stomatitis (types II and III) demonstrated increased recovery of microorganisms in the palatal mumsa in addition to sialadenitis. Only one proband showed increased growth of fungi. Hemophilus spp. and Bacteroides spp. were the predominating microorganisms in stomatitis types II and III. Shifts in the normal oral flora are suggested to be an important factor for the development of denture stomatitis. It is concluded that bacterial colonization on the palatal mucosa may play an important role in denture stomatitis in this relatively healthy propulation. □ Denture stomatitis; gen...

Eight bacterial strains belonging to 6 genera, 2 facultatively anaerobic and 6 obligately anaerobic species, isolated from an autogenously infected dental root canal in a monkey, were used for in vivo and in vitro interference studies. In the tissue cage studies Bacteroides oralis, Fusobaclerium necrophorum, Peptostreptococcus anaerobius and Streptococcus milleri dominated at the end of the experiment. They induced high liters of circulating antibodies in the rabbits. This result was in concordance with the development of a mixed infection in the dental apical region model in monkeys as revealed in previous experiments. In the test tube studies Streptococcus faecalis (Enterococcusfaecalis), a rapidly growing facultatively anaerobic bacterial species, overgrew and survived the tested anaerobes. On agar plates S. milleri was negatively influenced by 3 anaerobic species and S. faecalis. Factors interacting in vitro seemed to play a minor role in vivo. It appears that the tissue cage model offers a valuable in vivo model for studies of mixed anaerobic infections in terms of bacterial interference.

This report describes findings in microbial samples from 271 patients with lesions of the oral mucous membranes. Analyses were made on the basis of direct microscopy and cultivation on nonselective and selective media incubated under aerobic and anaerobic conditions. Growth of bacteria was semiquantitatively determined according to a five-grade scale. Among the 134 samples for direct microscopy, fungi in yeast as well as hyphae phase, were identified in 39 cases. Among the cultivated samples, Candida albicans was detected in 107 cases, of which 71 were full-denture wearers. Staphylococcus aureus, coliform bacteria and Klebsiella were the most frequently isolated “nonoral” bacteria. In some cases also Streptococcus pyogenes, Haemophilus influenzae, Pseudomonas or other gram-negative aerobic bacteria were found. In 84 cases the bacteria mentioned were registered as single “nonoral” infection, and in 63 cases combinations of “nonoral” species occurred. In 51 of these 63 cases C. albicans was also involved. In 31 cases a significant quantitative increase of one or more oral bacterial species was registered. In 93 cases there was no indication of a microbial cause of the lesion. On the basis of these microbial findings, it might be presupposed that in the majority of cases microorganisms were of primary or secondary pathogenic importance to the lesions.

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.

– Experimental infections in root canals with Streptococcus faecalisss. liqiuefaciens (Strep-MG4), Actinomyces bovis (Act-MO6) and Bacteroides oraiis (Bact-MC3) were studied in four immunized and five nonimmiLtnized monkeys. The immunization was performed using1 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 in 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 inmost 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 radiograpihic 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.

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.

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.

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.