Levels of HIV-1 in subgingival biofilm of HIV-infected patients.

AIM: The aims of the current study were to compare the levels of HIV-1 in the subgingival biofilm (SHVL) between detectable and undetectable plasmatic HIV-1 viral load (PHVL) in HIV-infected patients as well as to determine the association of SHVL with PHVL and clinical periodontal parameters. MATERIAL AND METHODS: Forty-one HIV-infected individuals were divided into two groups: detectable (21) and undetectable (20) PHVL. Subgingival biofilm samples were obtained for detection and quantification of HIV-1 by real-time RT-PCR. To estimate the effect of co-variables on the outcome undetectable SHVL, the Generalized Estimation Equation (GEE) was employed. RESULTS: Detectable SHVL was observed only in the detectable PHVL group and the detection of the HIV-1 was observed in 40% of these individuals. In the bivariate analysis between co-variables from the individual level and the outcome SHVL, significant difference was observed only for the CD4+ T lymphocytes levels (p = 0.017). The multiple logistic model demonstrated that only CD4+ T lymphocytes levels had a significant effect on the outcome undetectable SHVL [OR 8.85 (CI 3.6-9.2), p = 0.002]. CONCLUSION: HIV-1 can be detected and quantified in the subgingival biofilm of HIV-infected individuals, but these findings are not associated with PHVL and periodontal clinical parameters.

Characterization of proteolytic activities of Fusobacterium nucleatum.

This investigation attempted to detect the proteolytic activity of Fusobacterium nucleatum in living cells, lysate cells, and supernatant of cultures. The reactions were optimized in their pH, temperature, reaction time, enzyme source, and substrate volume. Synthetic substrates beta-naphthylamides (Cys-Na, Ser-Na, Leu-Na, Glu-Na, Lys-Na and BANA), carbobenzoxy L-tirosine p-nitrophenylester (CTN), and natural substrate azoalbumin were used. Reaction occurred with Cys-Na, Ser-Na, and Glu-Na in living cells and with Glu-Na, Leu-Na, and CTN substrates in lysate cells. The supernatant reacted only with Glu-Na. Optimal pH ranged from 6.0 to 7.5, except for CTN (pH 13), and optimal temperature, between 30 and 40 degrees C. Optimal reaction time was 60 min, except for Glu-Na in living cells (40 min), lysate cells (20 min), and CTN substrate (80 min). There was no activity with Lys-Na, BANA, and azoalbumin. Proteolytic activity was assessed by several inhibitors and the presence of metallo, serine, cysteine, and aspartic proteases were detected.

Bacteremia after Endodontic Procedures in Patients with Heart Disease: Culture and Molecular Analyses.

INTRODUCTION: Infective endocarditis (IE) is still associated with high mortality, and antibiotic prophylaxis strategies are under intense debate. We evaluated the incidence of bacteremia after root canal preparation in teeth with necrotic pulps and apical periodontitis. METHODS: Blood samples were taken before and 5 and 30 minutes after endodontic treatment in teeth with apical periodontitis from individuals at high (n = 21) or no risk (n = 11) for IE. The former received prophylactic antibiotic therapy. Bacteriologic samples were taken from root canals before chemomechanical preparation to confirm pulp infection. Samples were subjected to aerobic and anaerobic culture and quantitative real-time polymerase chain reaction (qPCR), the latter to determine the total bacterial and streptococcal levels. RESULTS: Culture revealed no bacteremia in all individuals. Analysis by qPCR showed that bacterial DNA occurred in all root canal samples. qPCR showed a similar incidence of bacteremia between patients who received or did not receive prophylactic antibiotic therapy (P > .05). In blood samples taken 5 minutes after endodontic procedures, bacteria were detected in 2 of 11 (18%) individuals not taking antibiotics and in 4 of 21 (19%) patients under prophylaxis. After 30 minutes, the incidence of bacteremia decreased to 2 of 21 (10%) in patients taking antibiotics and was undetectable in patients at no risk of IE. The incidence of bacteremia by streptococci was identical as that for total bacteria. CONCLUSIONS: No detectable bacteremia was evident by culture after treatment of infected root canals. Molecular analysis revealed bacterial DNA and streptococci in blood from some patients without a significant difference between individuals receiving or not receiving antibiotic prophylaxis.

Antimicrobial activity of a temporary sealant used in endodontic treatment: An in vitro study.

OBJECTIVE: The present study is aimed to evaluate the antimicrobial action of Coltosol(®) in direct contact with human saliva. MATERIALS AND METHODS: Twelve different individuals were selected. Saliva samples were evaluated at four different time periods: Baseline 1 (T1-initial control), T2 (2 h), T4 (24 h after contact with a standardized sample of a coronary sealer) and baseline 2 (T3-final control). Seeded plates were incubated at 37°C in a bacterial incubator for a period of 48-72 h. After the incubation period, the colony forming units were counted, and the results compared. RESULTS: Differences were statistically significant. There was an inhibition of bacterial growth after the first 2 h of contact and an increase in the number of bacteria after 24 h of direct contact between the material and the saliva. Coltosol(®) presented bacterial growth inhibition in direct contact with saliva. This inhibitory effect tended to decrease over time, as shown by the two periods when the material was in contact with different samples of saliva. CONCLUSIONS: The antimicrobial activity of the material is an important feature; however, other physical and chemical properties of the coronary temporary sealer should be considered.

Peptostreptococcus micros in primary endodontic infections as detected by 16S rDNA-based polymerase chain reaction.

A 16S rDNA-based polymerase chain reaction (PCR) method was used to detect Peptostreptococcus micros in primary root canal infections. Samples were collected from 50 teeth having carious lesions, necrotic pulps, and different forms of periradicular diseases. DNA extracted from the samples was amplified using the PCR assay, which yielded a specific fragment of P. micros 16S rDNA. P. micros was detected in 6 of 22 root canals associated with asymptomatic chronic periradicular lesions (27.3%), 2 of 8 teeth with acute apical periodontitis (25%), and 6 of 20 cases of acute periradicular abscess (30%). In general, P. micros was found in 14 of 50 cases (28%). There was no correlation between the presence of P. micros and the occurrence of symptoms. Findings suggested that P. micros can be involved in the pathogenesis of different forms of periradicular lesions.

Elimination of Candida albicans infection of the radicular dentin by intracanal medications.

Fungi have been associated with cases of secondary or persistent root canal infections. The purpose of this study was to evaluate the effectiveness of four intracanal medications in disinfecting the root dentin of bovine teeth experimentally infected with Candida albicans. Infected dentin cylinders were exposed to four different medications: calcium hydroxide/glycerin; calcium hydroxide/0.12% chlorhexidine digluconate; calcium hydroxide/camphorated paramonochlorophenol/glycerin; and 0.12% chlorhexidine digluconate/zinc oxide. Specimens were in contact with the medications for 1 h, 2 days, and 7 days. The viability of C. albicans after exposure was evaluated by specimen incubation in culture medium to compare the effectiveness of the medications in disinfecting dentin. Results showed that the specimens treated with calcium hydroxide/camphorated paramonochlorophenol/ glycerin paste or with chlorhexidine/zinc oxide paste were completely disinfected after 1 h of exposure. Calcium hydroxide/glycerin paste only consistently eliminated C. albicans infection after 7 days of exposure. Calcium hydroxide mixed with chlorhexidine was ineffective in disinfecting dentin even after 1 week of medication exposure. Among the medications tested, the calcium hydroxide/camphorated paramonochlorophenol/glycerin paste and chlorhexidine digluconate mixed with zinc oxide were the most effective in eliminating C. albicans cells from dentinal specimens.

Fungal infection of the radicular dentin.

Although fungi have been detected in infected root canals, their precise role as endodontic pathogens has not yet been elucidated. The purpose of this study was to investigate the pattern of radicular dentin colonization by five fungal species. Bovine root sections were infected with each of the following fungal species: Candida albicans, Candida glabrata, Candida guilliermondii, Candida parapsilosis, and Saccharomyces cerevisiae. After 14 days, the sections were fixed in glutaraldehyde, split into two halves, critical point-dried in CO2, sputter-coated with gold, and examined under scanning electron microscopy. Regardless of the species, single or budding yeast cells were the only fungal forms observed. C. albicans colonized most of the specimens. On the other hand, the other four fungal species presented discrete or no colonization of the radicular dentin. C. albicans showed different patterns of dentin infection. In some specimens, colonization of the dentinal surface was slight and no penetration within dentinal tubules was observed. In the other specimens, some areas of the root canal walls were covered with large colonies of yeast cells and some dentinal tubules were heavily infected. The results suggested that whereas C. albicans showed the ability to colonize dentin, the other four fungal species did not. This can help to explain why C. albicans is the fungal species most often found in endodontic infections.

Efficacy of instrumentation techniques and irrigation regimens in reducing the bacterial population within root canals.

The purpose of this study was to compare the in vitro intracanal bacterial reduction produced by using two instrumentation techniques and different irrigation methods. Root canals inoculated with Enterococcus faecalis were prepared by using the following techniques and irrigants: alternated rotary motions (ARM) technique, hand nickel-titanium files and 2.5% sodium hypochlorite (NaOCl) as irrigant; ARM technique and combined irrigation with 2.5% NaOCl and citric acid; ARM technique and combined irrigation with 2.5% NaOCl and 2% chlorhexidine gluconate; and Greater Taper rotary files, using 2.5% NaOCl as irrigant. Controls were instrumented by using the ARM technique and irrigated with sterile saline. Canals were sampled before and after preparation. After serial dilution, samples were plated onto Mitis-Salivarius agar, and the colony forming units that were grown were counted. All test techniques and solutions significantly reduced the number of bacterial cells within the root canal (p < 0.05). There was no significant difference between the experimental groups (p > 0.05). Nonetheless, all of them were significantly more effective than the control group (p < 0.05). These findings support the importance of using antimicrobial irrigants during the chemomechanical preparation, regardless of the solutions or instrumentation techniques used.

Relationship between salivary flow rates and Candida counts in subjects with xerostomia.

OBJECTIVE: This study evaluated the relationship between salivary flow and Candida colony counts in the saliva of patients with xerostomia. STUDY DESIGN: Sialometry and Candida colony-forming unit (CFU) counts were taken from 112 subjects who reported xerostomia in a questionnaire. Chewing-stimulated whole saliva was collected and streaked in Candida plates and counted in 72 hours. Species identification was accomplished under standard methods. RESULTS: There was a significant inverse relationship between salivary flow and Candida CFU counts (P =.007) when subjects with high colony counts were analyzed (cutoff point of 400 or greater CFU/mL). In addition, the median sialometry of men was significantly greater than that of women (P =.003), even after controlling for confounding variables like underlying disease and medications. Sjögren's syndrome was associated with low salivary flow rate (P =.007). There was no relationship between the median Candida CFU counts and gender or age. There was a high frequency (28%) of mixed colonization. Candida albicans was the most frequent species, followed by C parapsilosis, C tropicalis, and C krusei. CONCLUSIONS: In subjects with high Candida CFU counts there was an inverse relationship between salivary flow and Candida CFU counts.

The association between detectable plasmatic human immunodeficiency virus (HIV) viral load and different subgingival microorganisms in Brazilian adults with HIV: a multilevel analysis.

BACKGROUND: This study investigates the association between detectable plasmatic human immunodeficiency virus (HIV) viral load (HVL) and high levels of periodontal- and non-periodontal-related microorganisms in the subgingival microbiota of individuals with HIV. METHODS: Thirty-seven individuals with HIV were divided into two groups: 1) detectable HVL (n = 15); and 2) undetectable HVL (n = 22). Subgingival biofilm samples were obtained, and the levels of 35 microbial species were determined by the checkerboard DNA-DNA hybridization method. Periodontal clinical measures and laboratory and sociodemographic data were also registered. χ(2) test, Fisher exact test, and Mann-Whitney U test were used to compare groups. Multilevel ordinal regression models were used to test the association between HVL and the levels of 35 microbial species in subgingival biofilm, adjusted for confounders. RESULTS: Of the 35 species studied, 11 (31.4%) showed higher mean levels in the detectable HVL group than undetectable HVL group (P <0.001). These species included Actinomyces naeslundii II, Actinomyces israelii, Actinomyces odontolyticus, Veillonella parvula, Capnocytophaga gingivalis, Eikenella corrodens, Campylobacter concisus, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Candida albicans. Significant associations between detectable HVL and high levels of microorganisms, adjusted for confounders, were observed for A. naeslundii I, Actinomyces gerencseriae, C. gingivalis, E. corrodens, C. concisus, Prevotella nigrescens, T. forsythia, and Dialister pneumosintes. CONCLUSION: Detectable plasmatic HVL in individuals with HIV was associated with elevated levels of known periodontal pathogens, such as P. nigrescens, T. forsythia, and E. corrodens, as well as C. concisus, C. gingivalis, and D. pneumosintes in the subgingival biofilm.

A prospective randomized trial to reduce oral Candida spp. colonization in patients with hyposalivation.

Low salivary flow rates are associated with higher oral Candida spp. counts, which may predispose to oral candidiasis. The aim of this study was to compare the effect of stimulating salivary flow rates with that of a regimen of chlorhexidine mouth rinse on the intensity of Candida colonization in patients with reduced salivary flow rates. Thirty-one outpatients were randomized to stimulate salivary output (group 1) or to receive chlorhexidine mouth rinses (group 2). Evaluations were performed at baseline (T0), at end of treatment (T1), and 15 days after last day of treatment (T2). Chewing-stimulated whole saliva samples were collected at each visit. Group 1 showed a constant reduction in median cfu counts, although the difference was significant only between T0 and T2 (p = 0.004). Group 2 showed a reduction in median Candida cfu counts between T0 and T1 (p = 0.01), but the counts increased at T2 (p = 0.01), and the difference between T0 and T2 was not significant (p = 0.8). In conclusion, patients who received salivary stimulation showed reductions of Candida cfu counts in saliva and a trend for increasing salivary flow rates between baseline and end of study evaluations. The use of chlorhexidine mouth rinses dramatically reduced Candida cfu counts, but when patients discontinued treatment, intensity of colonization rose again.

Influence of titanium surface roughness on attachment of Streptococcus sanguis: an in vitro study.

The purpose of the present study was to investigate the efficacy of the decontamination protocol for bacterial removal in titanium surfaces with three different levels of roughness using a high-pressure sodium bicarbonate device for 1 minute under aseptic conditions. Group 1 was composed of 10 as-machined titanium sheets and Groups 2 and 3 of titanium sheets blasted with aluminum oxide (Al2O3, alumina) particles with different diameters: Group 2 was blasted with 65-microm particles and Group 3 with 250-microm particles. The titanium specimens were sterilized and incubated in tubes containing a suspension of Streptococcus sanguis. The colony-forming units were counted before and after the application of the decontamination protocol. The arithmetic mean roughness (R(a)) per group was: Group 1, 0.17 microm +/- 0.01; Group 2, 1.14 microm +/- 0.15; and Group 3, 3.17 microm +/- 0.23. After the contamination period, Group 1 remained with 49 x 10(3) bacterial cells, and the bacterial concentrations of Groups 2 and 3 were 11 x 10(4) and 35 x 10(5), respectively. After the application of the decontamination protocol, no viable bacteria were detected. With the increase of the surface roughness, an exponential increase in bacterial cells was observed. The results showed that the decontamination protocol treatment with a high-pressure sodium bicarbonate device efficiently removed all bacterial cells in all surfaces tested. This indicates that high-pressure sodium bicarbonate spray should be used in the maintenance phase of implant treatment.

Susceptibility of Prevotella intermedia/Prevotella nigrescens (and Porphyromonas gingivalis) to propolis (bee glue) and other antimicrobial agents.

Black-pigmented gram-negative anaerobes such as Porphyromonas gingivalis and Prevotella intermedia are suspected pathogens in adult periodontitis, whereas Prevotella nigrescens has been associated with health. Antimicrobial resistance among bacteria from this group has been reported in the past decade. This research aimed to evaluate and compare the susceptibility profile of 17 P. intermedia/P. nigrescens isolates recovered from patients with periodontitis and three reference strains to six antimicrobials, prescribed in dentistry in Brazil, and propolis (bee glue). The antimicrobial agents tested were tetracycline, penicillin, clindamycin, erythromycin, metronidazole, meropenem and six ethanolic extracts of propolis (EEPs) from Brazil. The reference strains P. gingivalis ATCC 33277 and P. intermedia ATCC 25611 were used for determination of minimum bactericidal concentration (MBC) and for time-kill assay to the EEPs. All of the strains were susceptible to penicillin, erythromycin, meropenem, metronidazole and 95% of them (n=19) to tetracycline. Thirty six percent (n=7) of the P. intermedia/P. nigrescens strains tested were resistant to clindamycin. As for propolis activity, all strains were susceptible and the minimum inhibitory concentration values ranged from 64 to 256 microg/mL. For the reference strains P. gingivalis ATCC 33277 and Prevotella intermedia ATCC 25611 the MBC was 256 microg/mL and death was observed within 3 h of incubation for P. gingivalis and within 6 h for P. intermedia. The action of propolis (bee glue) against suspected periodontal pathogens suggests that it may be of clinical value.