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.

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.

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.

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.

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.

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.

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.

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.

Glass fibre-reinforced composite laced with chlorhexidine digluconate and yeast adhesion.

The aim of this study was to lace dental glass fibre reinforced composite (FRC) prepreg with chlorhexidine digluconate and to examine the adherence of common oral fungal pathogen Candida albicans to FRC made of the prepreg. Four different test and control material groups each comprising 16 test specimens ((5.0 x 5.0 x 0.8) mm3) each were used as substrates for C. albicans adherence. A porous polymer pre-impregnated woven glass fibre prepreg was laced with solution of chlorhexidine gluconate and it was used with autopolymerized denture base polymer to fabricate FRC test specimens. Control group (Group 1) consisted of FRC test specimens stored in water. In Group 2, the test specimens were stored in 10% chlorhexidine digluconate solution for 24 h. Group 3 consisted of specimens fabricated using such fibre reinforcements which were pre-soaked in 20% chlorhexidine digluconate and dried before preparation with denture base resin, and followed by storage of the specimens in water. Group 4 was similar to Group 3 but instead of water storage the specimens were immersed in 10% chlorhexidine digluconate for 24 h. For the candidal adhesion assay the test and control specimens were incubated in standardized suspensions of four different strains of C. albicans, rinsed and prepared for light-microscopy. The mean number of adherent cells in each group was counted microscopically and analysed statistically. There were significantly (P < 0.05) more adherent C. albicans cells found in Group 1 than in the other three groups which did not differ significantly from each other. The lowest numbers of adherent cells were found in Group 3. Pretreating the porous polymer pre-impregnated glass fibre reinforcement with chlorhexidine digluconate result in reduction in the number of adherent yeast cells on the surface FRC material.

Examination on Candida spp. in refractory periapical granulomas.

AIM: To examine the occurrence of Candida spp. in refractory periapical granulomas. METHODOLOGY: One hundred and three surgically removed periapical granulomas were subjected to molecular analysis for the occurrence of Candida albicans. DNA was extracted from the samples using a modified phenol/chloroform/isoamyl alcohol method and was subjected to polymerase chain reaction (PCR) with OPA-03 and repetitive sequence (GACA)4 primers. The PCR products were separated in agarose gel electrophoresis, stained with ethidium bromide, visualized using UV light and the sequences were analysed. Samples indicating possible occurrence of Candida were further investigated by histological and immunohistological methods. Periodic acid-Shiff staining (PAS) was used to detect yeast cells and hyphae, and specific monoclonal antibodies to recognize high molecular mass mannoproteins present in the C. albicans cell wall. DNA extraction was controlled by running PCR using beta-actin primers (a housekeeping gene). C. albicans CCUG19915, C. tropicalis ATCC750, C. krusei ATCC6258, C. guilliermondii ATCC6260 and C. glabrata CCUG32725 served as positive controls in PCR. A tissue preparation of chronic atrophic candidosis in oral buccal mucosa served as a positive control for histological and immunohistological examinations. RESULTS: Polymerase chain reaction with beta-actin primers indicated successful DNA extraction in 68 out of 103 samples. The majority of the samples (50) were negative whereas 18 of the samples showed PCR products indicating possible occurrence of Candida spp. PAS-staining and immunohistological examination of these samples were, however, negative. Further analysis of the PCR products revealed sequences not typical for Candida spp. CONCLUSIONS: Candida spp. do not seem to occur in periapical granuloma.

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.

Yeasts in apical periodontitis.

Microbiological reports of apical periodontitis have revealed that yeasts can be isolated from approximately 5-20% of infected root canals. They occur either in pure cultures or together with bacteria. Almost all isolated yeasts belong to the genus Candida, and the predominant species is C. albicans. Pheno- and genotypic profiles of C. albicans isolates show heterogeneity comparable with those of isolates from other oral sites. C. albicans expresses several virulence factors that are capable of infecting the dentin-pulp complex, including dentinal tubules. This causes, consequentially, an inflammatory response around the root apex, which suggests a pathogenic role for this organism in apical periodontitis. Yeasts are particularly associated with persistent root canal infections that do not respond favorably to conservative root canal therapy. This may be due to the resistance of all oral Candida species against a commonly used topical medicament, calcium hydroxide. However, other antimicrobial agents may offer alternative therapeutic approaches and improve the treatment of these persistent cases of apical periodontitis.

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.

Phenotypes and randomly amplified polymorphic DNA profiles of Candida albicans isolates from root canal infections in a Finnish population.

A total of thirty-seven Candida albicans isolates from root canal infections in a Finnish population were subtyped using phenotypic and genotypic methods. A previously described biotyping method based on the presence of five different enzymes, assimilation of eleven different carbohydrates and boric acid sensitivity of the yeasts was used to determine the phenotype. Commercially available API ZYM and API 20 C test kits were used to determine the presence of enzymes and assimilation of carbohydrates. The sensitivity of the isolates to boric acid was tested by their ability to grow on yeast-nitrogen-agar with incorporated boric acid (1.8 mg. ml(-1)). Combination of the tests revealed a total of 14 different phenotypes. The majority of the isolates, 26 strains, were classifiable into three major phenotypes: 16 isolates (43.2%) belonged to phenotype A1R, six (16.2%) to A1S and four (10.8%) to B1S. The remaining 11 phenotypes represented only a single isolate each. The randomly amplified polymorphic DNA profiles were used to determine the genotypes. For this purpose two different primers, RSD6 and RSD12 were used to develop a combination randomly amplified polymorphic DNA profile for each isolate. Altogether 31 genotypes were noted among the 37 isolates, of which only three pairs of isolates presented with congruent phenotypic and genotypic profiles. The heterogeneity of both the phenotypic and randomly amplified polymorphic DNA profiles of C. albicans isolates from root canal infections is akin to previous reports from other oral and non-oral sources in different geographic locales.

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.

Inactivation of root canal medicaments by dentine, hydroxylapatite and bovine serum albumin.

AIM: This study examined and compared the inhibition of the antibacterial effect of saturated calcium hydroxide solution, chlorhexidine acetate and iodine potassium iodide by dentine, hydroxylapatite and bovine serum albumin. METHODOLOGY: Enterococcus faecalis strain A197A prepared to a suspension of 3 x 10(8) cells per ml in 0.5% peptone water was used. Fifty microL of saturated calcium hydroxide solution, 0.05% chlorhexidine acetate or 0.2/0.4% iodine potassium iodide were incubated at 37 degrees C with 28 mg dentine powder (DP), hydroxylapatite (HA) or bovine serum albumin (BSA) in 50 microL water for 1 h before adding 50 microL of the bacterial suspension. Samples for bacterial culturing were taken from the suspension 1 and 24 h after adding the bacteria. In further experiments, the amount of dentine was stepwise reduced from 28 mg 150 microL-1 to 2.8 mg 150 microL-1. RESULTS: Calcium hydroxide was totally inactivated by the presence of 28 mg of DP, HA or BSA. Chlorhexidine (0.05%) was strongly inhibited by BSA and slowed down by dentine. However, HA had little or no inhibitory effect on chlorhexidine. The antibacterial effect of 0.2/0.4% iodine potassium iodide on E. faecalis was totally inhibited by dentine (28 mg), but was practically unaffected by HA or BSA. A stepwise reduction of dentine from 28 mg 150 microL-1 to 2.8 mg 150 microL-1 was followed by a similar reduction of the inhibition of the antibacterial activity of chlorhexidine. Iodine potassium iodide was not inhibited at all with dentine amounts less than 28 mg. However, the effect of saturated calcium hydroxide solution was totally eliminated by dentine, in all four concentrations. CONCLUSION: Inhibition by dentine of the antibacterial activity of calcium hydroxide, chlorhexidine and iodine potassium iodide occurs by different mechanisms. Different components of dentine may be responsible for the inhibition of these three medicaments. Calcium hydroxide was particularly sensitive to inhibition by both inorganic and organic compounds.