Associations of oral fluid MMP-8 with periodontitis in Swiss adult subjects.

OBJECTIVE: MMP-8 is a prominent collagenase in periodontal disease. This cross-sectional study examined whether MMP-8 levels in saliva and gingival crevicular fluid (GCF) are associated with periodontitis in a Swiss population. SUBJECTS AND METHODS: A total of 258 subjects (107 m, 151 f, mean age: 43.5 yr; range: 21-58 yr) acquired from the Swiss bone marrow donor registry participated in the study. Saliva and GCF samples were collected from subjects followed by a thorough dental and periodontal examination. MMP-8 levels were determined with immunofluorometric assay. Associations of MMP-8 levels with periodontal diagnosis, probing pocket depth (PPD) and bleeding on probing were statistically analysed with Pearson chi-square test, Spearman's rho and logistic regression analysis. RESULTS: MMP-8 in GCF correlated with MMP-8 in saliva (p < .001). Periodontitis was more common (p < .001) among subjects with high levels of MMP-8 in saliva and/or GCF compared with subjects with low levels of MMP-8. Higher MMP-8 levels in GCF and saliva were associated with any periodontal diagnosis (mild, moderate or severe), greater PPD, and bleeding on probing (p < .05). When age, gender, smoking, body mass index, number of medications and decayed, missing and filled teeth were adjusted for, all observed associations remained statistically significant. The area under curve of receiver-operating characteristic was 0.67 for saliva and 0.71 for GCF. CONCLUSION: Elevated MMP-8 levels both in saliva and GCF are associated with periodontitis in a normal adult population.

Post-thrombolytic blood pressure and symptomatic intracerebral hemorrhage.

BACKGROUND AND PURPOSE: Most guidelines for intravenous thrombolysis (IVT) in acute ischaemic stroke patients advise keeping systolic blood pressure (BP) below 180/105 mmHg prior to the bolus injection. Less is known about optimal management of BP thereafter. We assessed temporal changes in post-thrombolytic systolic BP values and their impact on development of symptomatic intracerebral hemorrhage (sICH). METHODS: The study cohort included 1868 consecutive acute ischaemic stroke patients treated with IVT at the Helsinki University Central Hospital. sICH was defined according to the European Cooperative Acute Stroke Study II (ECASS-II) (primary outcome), National Institute of Neurological Disorders and Stroke, and Safe Implementation of Thrombolysis in Stroke criteria. We evaluated BP at admission, prior to IVT and at 2, 4, 8, 12, 24 and 48 h after thrombolysis. We used univariate and multivariable models to test the effect of BP at various time-points on development of post-thrombolytic sICH. RESULTS: Prevalence of sICH in the cohort was 5.8% (ECASS-II). Patients with sICH had significantly higher systolic BP at several time-points after IVT compared with those without sICH (P < 0.01 at 2 and 4 h; P < 0.05 at 12 and 48 h). The odds ratios for development of sICH per 10 mmHg increase in BP were 1.14 [95% confidence interval (CI), 1.03-1.25], 1.14 (95% CI, 1.03-1.25), 1.12 (95% CI, 1.01-1.23) and 1.12 (95% CI, 1.01-1.23), respectively. At 8 h, we observed a trend (P = 0.07) for ECASS-II and a significant effect (P < 0.05) for National Institute of Neurological Disorders and Stroke, and Safe Implementation of Thrombolysis in Stroke criteria. Thus, the only time-point with no difference observed was 24 h. CONCLUSIONS: Patients with post-thrombolytic sICH have significantly higher systolic BP at several time-points compared with patients without sICH.

Effects of fluorides on Candida albicans.

AIMS: To assess whether a short exposure of Candida albicans to commonly used fluorides would affect growth, cell surface hydrophobicity, and adherence to buccal epithelial cells. METHODS: Candida albicans ATCC 90028 and 11 clinical isolates were used. Minimal inhibitory concentrations (MICs) of sodium fluoride (NaF) and of an amine fluoride / stannous fluoride combination (AmF / SnF2) were determined. Yeasts were exposed to MICs of tested agents for 1 h. Subsequently, their growth was recorded spectrophotometrically. Their cell surface hydrophobicity was assessed with n-hexadecane. Adherence to buccal epithelial cells was determined microscopically. Phosphate buffered saline (PBS) and chlorhexidine digluconate (CHX) served as controls. All results were analyzed by one-way ANOVA. RESULTS: MICs of AmF / SnF(2) and CHX varied between 1 and 4 microg ml(-1), whereas those of NaF were 15 000 microg ml(-1). Statistically significant growth inhibition was detected after AmF / SnF(2) (OD(24 h) +/- SD 0.457 +/- 0.059) and CHX (0.175 +/- 0.065) in comparison with PBS (0.925 +/- 0.087) and NaF (0.813 +/- 0.081). All strains demonstrated uniform behavior. Only minor changes in cell surface hydrophobicity and adherence to buccal epithelial cells (BEC) were detected. CONCLUSION: Growth inhibition of AmF / SnF(2) was comparable with that of CHX whereas NaF had a weaker effect. Exposure to the fluorides did not seem to alter the cell surface hydrophobicity nor adherence to BEC.

Do bioactive glasses convey a disinfecting mechanism beyond a mere increase in pH?

AIM: To test whether bioactive glasses kill microbiota via mineralization or the release of ions other than sodium. METHODOLOGY: Flame-spray synthesis was applied to produce nanometric glasses of different sodium content and constant Ca/P ratio: 28S5, 45S5 and 77S. Calcium hydroxide and nanometric tricalcium phosphate (TCP) were used as controls. Apatite induction was monitored by Raman spectroscopy. Bovine dentine disks with adherent Enterococcus faecalis cells were exposed to test and control suspensions or buffered solutions for 1 h, 1 day and 1 week. Colony-forming units were counted and disks were inspected using scanning electron microscopy. Suspension supernatants and solutions were analysed for their pH, osmolarity, calcium and silicon content. RESULTS: Sodium containing glasses induced pH levels above 12, compared with less than pH 9 with sodium-free 77S. Calcium hydroxide, 45S5 and 28S5 killed all bacteria after 1 day and lysed them after 1 week. TCP caused the highest apatite induction and substantial calcification on bacteria adhering to dentine, but did not reduce viable counts. 77S achieved disinfection after 1 week without visible apatite formation, whilst the buffer solution at pH 9 caused only minimal reduction in counts. CONCLUSION: Bioactive glasses have a directly and an indirectly pH-related antibacterial effect. The effect not directly linked to pH is because of ion release rather than mineralization.

Antimicrobial effect of nanometric bioactive glass 45S5.

Most recent advances in nanomaterials fabrication have given access to complex materials such as SiO(2)-Na(2)O-CaO-P(2)O(5) bioactive glasses in the form of amorphous nanoparticles of 20- to 60-nm size. The clinically interesting antimicrobial properties of commercially available, micron-sized bioactive glass 45S5 have been attributed to the continuous liberation of alkaline species during application. Here, we tested the hypothesis that, based on its more than ten-fold higher specific surface area, nanometric bioactive glass releases more alkaline species, and consequently displays a stronger antimicrobial effect, than the currently applied micron-sized material. Ionic dissolution profiles were monitored in simulated body fluid. Antimicrobial efficacy was assessed against clinical isolates of enterococci from persisting root canal infections. The shift from micron- to nano-sized treatment materials afforded a ten-fold increase in silica release and solution pH elevation by more than three units. Furthermore, the killing efficacy was substantially higher with the new material against all tested strains.

Differential effects of noxious conditioning stimulation of the cheek by capsaicin on human sensory and inhibitory masseter reflex responses evoked by tooth pulp stimulation.

In this study, we investigated whether selective activation of nociceptive primary afferent fibers by capsaicin would induce modulations on tooth-pulp-evoked sensory or inhibitory masseter reflex responses in healthy human subjects. The contribution of central N-methyl-D-aspartate (NMDA) receptor mechanisms in capsaicin-induced effects on sensory or reflex responses was evaluated by dextromethorphan, an NMDA-receptor antagonist. The inhibitory masseter reflex was evoked by electrical stimulation (constant current, single pulses) of the upper incisor while the subject was biting at 10% of his maximal force. The sensation of the tooth pulp stimulation was evaluated by visual analogue scale (VAS). The magnitude, duration, and the the latency of the reflex were determined by bite force measurements. The inhibitor masseter reflex could be induced by non-painful tooth pulp stimulation, and the inhibition was enhanced as a function of increasing stimulus intensity. Capsaicin (1%) applied topically to the skin of the cheek produced a spontaneous burning pain sensation. During capsaicin treatment, the VAS ratings for the sensation induced by tooth pulp stimulation were significantly reduced, whereas no significant changes were found in the tooth-pulp-induced masseter reflex responses. Double-blind treatment with dextromethorphan at a dose of 100 mg (= the highest does without side-effects) had no effect on sensory or reflex responses. These data indicate that noxious stimulation of the facial skin by capsaicin induces differential effects on tooth-pulp-evoked sensory and inhibitory masseter reflex responses: Sensory responses are strongly attenuated, while masseter reflex responses are not significantly changed. Dextromethorphan at a clinically applicable dose does not influence tooth-pulp-evoked sensory or reflex responses or their modulation by capsaicin. Furthermore, the lack of modulation of the masseter reflex response by capsaicin differs from the capsaicin-induced enhancement of a nocifensive limb flexion reflex described earlier.

In vitro yeast infection of human dentin.

An in vitro model was developed for investigation of Candida albicans penetration into human dentinal tubules. The model consisted of a dentin disc mounted between two cuvettes that each had a circular opening facing the disc. The cuvettes were filled with Tryptic-Soy-Broth, and the pulpal side cuvette was inoculated with C. albicans and incubated at 37 degrees C in air until growth occurred in the uninoculated cuvette or up to 30 days. The system was also used with Enterococcus faecalis. Completely glue-covered dentin specimens served as negative controls. Brown & Brenn-stained histological preparations of the specimens were examined with light microscopy. The time needed before growth occurred in the uninoculated cuvette showed great variation with C. albicans, whereas E. faecalis penetrated within 1 to 5 days of incubation. Slight penetration both by hyphae and yeast cells was observed in specimens inoculated with C. albicans, whereas specimens inoculated with E. faecalis showed deep and effective penetration. This study demonstrates the penetration of dentin as a possible pathway of infection by C. albicans. However, dentin penetration by C. albicans was slow and limited in comparison with E. faecalis.

Clinical performance of 3 endodontic sealers.

OBJECTIVE: Calcium hydroxide is used in endodontics as an interappointment dressing. Its inclusion in salicylate resin or zinc oxide-eugenol-based sealers for filling root canals also may lead to a better treatment outcome. The purpose of the present study was to compare the clinical/radiographic treatment outcome of 3 sealers, 2 of which contain calcium hydroxide. STUDY DESIGN: Two hundred and four teeth underwent a standardized endodontic treatment regimen and were assigned to 1 of 3 groups at the time of root filling: group PS, teeth filled with gutta-percha and Procosol sealer; group CR, teeth filled with gutta-percha and CRCS sealer; and group SA, teeth filled with gutta-percha and Sealapex sealer. The results of the treatment were assessed yearly for up to 4 years by clinical and radiologic (periapical index scores) controls. The ridit statistic (r) was used to compare PAI scores among the groups. RESULTS: The overall treatment results were comparable with, but slightly poorer than, results previously obtained from patients seen at the Dental School at the University of Oslo. During the first year after filling, the mean ridit value decreased from .51 +/- .039 to .31 +/- .042 (Deltar = .20) in the SA group. Corresponding values went from .43 +/- .030 to .38 +/- .035 (Deltar = .05) in the PS group and from 37 +/- .045 to .34 +/- .050 (Deltar = .03) in the CR group. At the 2-year examination, teeth in group SA had slightly better periapical conditions (r =.22 +/-.045) than did teeth in group PA (r = .30 +/- .037) or in group CR (r = .30 +/- 052). The difference was statistically significant at P = .01. By years 3 and 4, no significant difference among the groups was detected. CONCLUSIONS: The overall influence of the sealer on treatment outcome was small. Root fillings with salicylate resin containing Ca(OH)2 may support more rapid healing of apical periodontitis or operative trauma, but the results after 3 and 4 years were as good for zinc oxide-eugenol-based sealers with or without Ca(OH)2.

Sicca symptoms and their impact on quality of life among very long-term survivors after hematopoietic SCT.

The objective of this prospective cross-sectional case-control study was to examine the prevalence of dryness symptoms and its impact on quality of life (QoL) among very long-term survivors after hematopoietic SCT (HSCT) in comparison with their respective sibling donors. Forty-four allogeneic HSCT recipients with a long-term survival (median: 17.5; range: 11-26 years) were included. Their respective, HLA-identical sibling donors served as controls. Clinical examinations included saliva flow rates (SFR) and the Schirmer's test. The presence of sicca symptoms of mouth, eyes and skin were inquired. The social functioning (SF)-36 questionnaire was applied. Recipients had lower (P<0.01) unstimulated and stimulated mean SFR than donors. Schirmer's test results <5 mm was found in 45% of the recipients in comparison with 27% of the donors (P = 0.07). Xerostomia (34 vs 4 subjects), xerophtalmia (23 vs 3) and dry skin (32 vs 12) were reported more often by the recipients than donors (P<0.001). Sicca symptoms and their objective findings correlated with QoL. The mean SF-36 scores of the donors were significantly higher than those of the recipients for physical component summary. In conclusion, sicca symptoms are common amongst long-term survivors of HSCT and affect remarkably the QoL.

Antimicrobial activity of Streptococcus salivarius K12 on bacteria involved in oral malodour.

OBJECTIVE: To investigate the antimicrobial activity of the bacteriocin-producing strain Streptococcus salivarius K12 against several bacteria involved in halitosis. DESIGN: The inhibitory activity of S. salivarius K12 against Solobacterium moorei CCUG39336, four clinical S. moorei isolates, Atopobium parvulum ATCC33793 and Eubacterium sulci ATCC35585 was examined by a deferred antagonism test. Eubacterium saburreum ATCC33271 and Parvimonas micra ATCC33270, which have been tested in previous studies, served as positive controls, and the Gram-negative strain Bacteroides fragilis ZIB2800 served as a negative control. Additionally, the occurrence of resistance in S. moorei CCUG39336 to S. salivarius K12 was analysed by either direct plating or by passage of S. moorei CCUG39336 on chloroform-inactived S. salivarius K12-containing agar plates. RESULTS: S. salivarius K12 suppressed the growth of all Gram-positive bacteria tested, but the extent to which the bacteria were inhibited varied. E. sulci ATCC35585 was the most sensitive strain, while all five S. moorei isolates were inhibited to a lesser extent. Natural resistance seems to be very low in S. moorei CCUG39336, and there was only a slight decrease in sensitivity after exposure to S. salivarius K12 over 10 passages. CONCLUSION: Our studies demonstrate that S. salivarius K12 has antimicrobial activity against bacteria involved in halitosis. This strain might be an interesting and valuable candidate for the development of an antimicrobial therapy for halitosis.

Longitudinal assessment of hematopoietic stem cell transplantation and hyposalivation.

Hyposalivation is a common adverse effect of anti-neoplastic therapy of head and neck cancer, causing impaired quality of life and predisposition to oral infections. However, data on the effects of hematopoietic stem cell transplantation (HSCT) on salivary secretion are scarce. The present study determined stimulated whole-saliva flow rates in HSCT recipients in comparison with a healthy control group. Stimulated whole-saliva flow rates of 228 allogeneic HSCT recipients (134 males, 94 females; mean age, 43 yrs) were examined pre-HSCT and 6, 12, and 24 months post-HSCT. Healthy individuals (n = 144; 69 males, 75 females; mean age, 46 yrs) served as the control group. Stimulated saliva flow rates (mL/min) were measured and analyzed statistically, stratifying for hematological diagnoses and conditioning therapy. Hyposalivation (≤ 0.7 mL/min) was found in 40% (p < 0.00001), 53% (p < 0.00001), 31% (p < 0.01), and 26% (n.s.) of the recipients pre-HSCT, and 6, 12, and 24 months post-HSCT, respectively, whereas 16% of the control individuals had hyposalivation. Severe hyposalivation (≤ 0.3 mL/min) was found in 11%, 18%, 4%, and 4% of the recipients pre-HSCT, and 6, 12, and 24 months post-HSCT, respectively. Additionally, conditioning regimen and sex had an impact on saliva flow. In conclusion, hyposalivation was observed to be a common but generally reversible complication among HSCT recipients.

Fine-tuning of bioactive glass for root canal disinfection.

An ideal preparation of 45S5 bioactive glass suspensions/slurries for root canal disinfection should combine high pH induction with capacity for continuing release of alkaline species. The hypothesis of this study was that more material per volume of bioactive glass slurry is obtained with a micrometric material (< 5 microm particle size) or a micrometric/ nanometric hybrid, rather than a solely nanometric counterpart. This should correlate with alkaline capacity and antimicrobial effectiveness. Slurries at the plastic limit were prepared with test and reference materials in physiological saline. Total mass and specific surface area of glass material per volume were determined. Continuous titration with hydrochloric acid was performed, and antimicrobial effectiveness was tested in extracted human premolars mono-infected with E. faecalis ATTC 29212 (N = 12 per material). While the nanometric slurry had a 12-fold higher specific surface area than the micrometric counterpart, the latter had a considerably higher alkaline capacity and disinfected significantly better (Fisher's exact test, P < 0.05). The hybrid slurry behaved similarly to the micrometric preparation.

Octenidine in root canal and dentine disinfection ex vivo.

AIM: The aim of the present study was to investigate the antimicrobial activity of octenidine on Enterococcus faecalis ATCC 29212 in a dentine block model. METHODOLOGY: Fifty-six root segments of extracted human teeth were infected with E. faecalis for 4 weeks. Octenidine-phenoxyethanol gel (1 : 1) was applied for different timing: 1 min, 10 min, 7 days and in a different formula (1 : 3) for 10 min. Three samples were chosen for the group with placebo gel and for the group without infection (negative control). Dentine samples were collected, and the total count of bacteria and colony-forming units were determined. In addition, for controls and the 10 min group with 1 : 1 gel, the proportion of viable bacteria (PVB) was assessed. RESULTS: Octenidine was particularly effective after incubation periods of 10 min and 7 days. The mean PVB decreased significantly from 57.2% to 5.7% after 10 min application. After 7 days, only one of 10 samples showed positive culture. CONCLUSION: The present study showed the effectiveness of octenidine against E. faecalis in dentine disinfection. Further laboratory and clinical studies are required.

In vitro antifungal effect of amine fluoride-stannous fluoride combination on oral Candida species.

OBJECTIVE: The combination of amine fluoride and stannous fluoride (AmF/SnF2) was, by chance, found to be antifungal in a clinical trial. This study investigated its effect on pathogenic Candida species with the hypothesis that the antifungal action on different species is variable. MATERIALS AND METHODS: Growth inhibition effect of Meridol mouth rinse which contains 250 ppm AmF/SnF2 was evaluated on 43 reference and clinical strains of Candida albicans, C. dubliniensis, C. glabrata, C. guilliermondii, C. krusei, C. parapsilosis, and C. tropicalis. Meridol base solution without AmF/SnF2 was used as a negative control. RESULTS: Undiluted Meridolmouth rinse killed most study strains within a few minutes. In ascending order, C. parapsilosis, C. tropicalis, C. albicans, C. glabrata, C. krusei and C. dubliniensis showed higher resistance against AmF/SnF2 than C. guilliermondii. CONCLUSION: AmF/SnF2 could be used as a potent adjunct to antifungal therapy for oral yeasts. Although different Candida species demonstrated variable sensitivity the most prevalent oral yeast C. albicans appeared sensitive to the AmF/SnF2 combination.

A comparative study on the disinfection potentials of bioactive glass S53P4 and calcium hydroxide in contra-lateral human premolars ex vivo.

AIM: To evaluate the effects of bioactive glass S53P4 versus calcium hydroxide when used as dressings in contra-lateral human premolars infected with Enterococcus faecalis ATCC 29212. METHODOLOGY: Pairs of contra-lateral premolar teeth plus single control premolars were obtained from 23 individuals aged 10-26 years undergoing orthodontic treatment. Root canals of teeth with fully formed apices (nine contra-lateral pairs, seven controls) were instrumented using a size 60 FlexoFiles 2 mm short of canal length. Canals with open apices (six contra-lateral pairs, four controls) were circumferentially instrumented using a FlexoFile. Root canals were rinsed with 1% sodium hypochlorite and 10% citric acid. Teeth were then suspended in tryptic soy broth (TSB) and autoclaved. Positive controls and study teeth were infected with E. faecalis ATCC 29212 for 2 weeks in TSB, while negative controls were kept in sterile TSB. Subsequently, contra-lateral premolars were dressed with bioactive glass S53P4 (BAG) or calcium hydroxide suspensions for 10 days. Dentine samples were obtained from teeth with fully formed apices using ISO-size 70, 80 and 90 FlexoFiles to working length and cultured. Teeth with open apices were fixed, fractured and examined using scanning electron microscopy (SEM). RESULTS: Calcium hydroxide had a strong antibacterial effect and was significantly more effective than BAG in preventing residual bacterial growth (P < 0.01). SEM analysis revealed apparent substance-specific modes of action. CONCLUSIONS: Calcium hydroxide was an effective disinfectant in human teeth.

Adherence of Candida species to newly polymerized and water-stored denture base polymers.

PURPOSE: The aim of this in vitro study was to examine the adherence of yeasts to newly polymerized and water-stored denture base polymers using four Candida strains with different cell surface hydrophobicities. MATERIALS AND METHODS: Thirty-two autopolymerized denture base polymer specimens were stored in distilled water at 37 degrees C for 7 days and 32 were newly polymerized. Sixteen specimens of each group were pretreated with unstimulated mixed saliva (saliva group), and 16 were pretreated with phosphate-buffered saline ([PBS] PBS group) at 37 degrees C for 1 hour. Hydrophobicity of the newly polymerized and water-stored specimen surfaces was determined by contact angle measurements. C guilliermondii, C albicans, C glabrata, and C tropicalis were grown on tryptic soy agar. They were pretreated either with saliva or PBS and suspended in PBS. Four parallel test specimens were incubated without agitation in each yeast suspension at 37 degrees C for 1 hour, washed, and allowed to dry in air. Adherent cells were fixed, gram stained, and counted from 10 high-power light-microscopy fields of each specimen. RESULTS: Enhanced adherence of yeasts was observed in water-stored test specimens in comparison to newly polymerized test specimens. Salivary pellicle reduced the hydrophobicity of test specimens and the adherence of yeasts. No differences in contact angles of distilled water between newly polymerized and water-stored polymers were observed. CONCLUSION: Yeasts seem to adhere less to newly polymerized than water-stored denture base polymer. This may be due to the release of residual monomer from the newly polymerized material.

Adherence of Candida albicans to the surface of polymethylmethacrylate--E glass fiber composite used in dentures.

PURPOSE: The use of reinforcing fibers in dentures has raised concerns about possible increased adherence of yeasts to the surface. The aim of this in vitro study was to compare the adherence of Candida albicans to the surface of denture-base polymer and to E-glass fibers. MATERIALS AND METHODS: Test specimens were made from an autopolymerized denture-base resin (Palapress) reinforced with preimpregnated unidirectional E-glass fibers, which were exposed at the surface. The test specimens were pretreated with parotid saliva and incubated without agitation in standardized yeast suspensions (10(8) colony-forming units per mL) in phosphate-buffered saline at 37 degrees C for 1 hour. The test specimens were then washed to remove nonadherent cells. After being air dried, they were sputter coated with gold-palladium for scanning electron microscopy (SEM). To compare the adherence to different surfaces, the number of yeast cells found either on the polymer matrix or on the glass fibers was counted from SEM fields (170 microns x 120 microns, 600 x) of randomly selected areas. RESULTS: The mean density of yeast cell found on the surface of the polymer matrix was significantly higher (P < 0.001) than that on the surface of glass fibers. The number of adherent yeast cells found at the interface between the fibers and polymer matrix was high. CONCLUSION: The adherence of C albicans to E-glass fibers was lower than to polymer matrix in the denture composite. If fibers are exposed only during polishing of the composite, the reinforcing material appears not to increase the adherence of this common oral yeast. However, areas with permanently exposed fibers may provide mechanical retention for yeast cells at the interface of the components.

Interactions of ethylenediamine tetraacetic acid with sodium hypochlorite in aqueous solutions.

AIM: To evaluate interactions of ethylenediamine tetraacetic acid (EDTA) with sodium hypochlorite (NaOCl). METHODOLOGY: Solutions consisting of 8.5% EDTA and 0.5% NaOCl were compared to a 1 : 1 (w/w) mixture of 17% EDTA and 1% NaOCl for their calcium-chelating, tissue-dissolving, and antimicrobial properties. Amounts of available chlorine were determined in the EDTA/NaOCl solutions with an iodine/thiosulphate titration method. Calcium chelation capacity was titrated with a pure calcium solution using a murexide indicator. Weight loss of porcine palatal mucosal specimens incubated in the test solutions was measured over time. Antimicrobial potential of pure solutions and the combination was recorded using an agar diffusion test in plates incubated with Enterococcus faecalis or Candida albicans. RESULTS: The presence of hypochlorite had little effect on the calcium-chelating ability or on the antimicrobial potential of EDTA. Available chlorine content decreased to 0.06% in the combined EDTA-NaOCl solution compared to 0.50% in an equivalent NaOCl mixture with deionized water. The EDTA-NaOCl solution did not dissolve more tissue than an equivalent pure EDTA solution at any time (anova, P > 0.05). CONCLUSIONS: Ethylenediamine tetraacetic acid retained its calcium-complexing ability when mixed with NaOCl, but EDTA caused NaOCl to lose its tissue-dissolving capacity and virtually no free chlorine was detected in the combinations. Clinically, this suggests that EDTA and NaOCl should be used separately. In an alternating irrigating regimen, copious amounts of NaOCl should be administered to wash out remnants of the EDTA.

In vitro susceptibility of Candida albicans isolates from apical and marginal periodontitis to common antifungal agents.

The susceptibility of a total of 70 Candida albicans strains to five common antifungal agents was determined. Thirty-five of the strains were isolated from persistent cases of apical periodontitis and 35 from cases of marginal periodontitis. The susceptibility of the strains to amphotericin B, 5-fluorocytosine and three azoles: fluconazole, miconazole and clotrimazole, was tested. The antifungal agents and yeast inoculums were prepared according to the NCCLS (National Committee for Clinical Laboratory Standards) recommendations. The yeasts were incubated with ten different concentrations of antifungal agents at 35 degrees C for 48 h. Yeast growth was measured spectrophotometrically. All strains from both isolation sources were susceptible to low concentrations of amphotericin B and 5-fluorocytosine, whereas the susceptibility to the three azoles varied, and three of the strains showed azole cross-resistance. These findings are in agreement with recent reports of increased azole resistance in Candida species in general and suggest the possibility that the oral cavity may act as a reservoir of resistant yeast isolates in systemic infections.

Inactivation of local root canal medicaments by dentine: an in vitro study.

AIMS: The aim of the study was to investigate the inactivation by dentine of the antibacterial activity of various commonly used local root canal medicaments. METHODOLOGY: The medicaments tested were saturated calcium hydroxide solution, 1% sodium hypochlorite, 0.5% and 0.05% chlorhexidine acetate, and 2/4% and 0.2/0.4% iodine potassium iodide. Dentine was sterilized by autoclaving and crushed into powder with a particle size of 0.2-20 microns. Aliquots of dentine suspension were incubated with the medicaments in sealed test tubes at 37 degrees C for 24 h or 1 h before adding the bacteria. In some experiments bacteria were added simultaneously with dentine powder and the medicament. Enterococcus faecalis A197A was used as a test organism. Samples for bacterial culturing were taken from the suspensions at 5 min, 1 h and 24 h after adding the bacteria. RESULTS: Dentine powder had an inhibitory effect on all medicaments tested. The effect was dependent on the concentration of the medicament as well as on the length of the time the medicament was preincubated with dentine powder before adding the bacteria. The effect of calcium hydroxide on E. faecalis was totally abolished by the presence of dentine powder. Similarly, 0.2/0.4% iodine potassium iodide lost its effect after preincubation for 1 h with dentine before adding the bacteria. The effect of 0.05% chlorhexidine and 1% sodium hypochlorite on E. faecalis was reduced but not totally eliminated by the presence of dentine. No inhibition could be measured when full strength solutions of chlorhexidine and iodine potassium iodide were used in killing E. faecalis. CONCLUSIONS: The dentine powder model appears to be an efficient tool for the study of interactions between local endodontic medicaments, dentine, and microbes.