Influence of antimicrobial solutions in the decontamination and adhesion of glass-fiber posts to root canals

Objective

This study evaluated the effect of root canal disinfectants on the elimination of bacteria from the root canals, as well as their effect on glass-fiber posts bond strength.

Material and Methods

Fifty-three endodontically treated root canals had post spaces of 11 mm in length prepared and contaminated with E. faecalis. For CFU/ml analysis, eight teeth were contaminated for 1 h or 30 days (n=4). Teeth were decontaminated with 5% NaOCl, 2% CHX, or distilled water. As control, no decontamination was conducted. After decontamination, sterile paper points were used to collect samples, and CFU/ml were counted. For push-out, three groups were evaluated (n=15): irrigation with 2.5% NaOCl, 2% CHX, or sterile distilled water. A bonding agent was applied to root canal dentin, and a glass-fiber post was cemented with a dual-cured cement. After 24 h, 1-mm-thick slices of the middle portion of root canals were obtained and submitted to the push-out evaluation. Three specimens of each group were evaluated in scanning electron microscopy (SEM). Data were analyzed with one-way ANOVA and Dunnett’s T3 test (α=0.05).

Results

The number of CFU/ml increased from 1 h to 30 days of contamination in control and sterile distilled water groups. Decontamination with NaOCl was effective only when teeth were contaminated for 1 h. CHX was effective at both contamination times. NaOCl did not influence the bond strength (p>0.05). Higher values were observed with CHX (p<0.05). SEM showed formation of resin tags in all groups.

Conclusion

CHX showed better results for the irrigation of contaminated root canals both in reducing the bacterial contamination and in improving the glass-fiber post bonding.     

Staphylococcus aureus as source of catheter‐related bloodstream infection evaluated by PFGE and rep‐PCR typing in a Brazilian hospital

Staphylococci are a common cause of catheter‐related bloodstream infection (CR‐BSI), and epidemiological typing is an important tool for effective infection control. This study evaluated by PFGE and rep‐PCR whether Staphylococcus aureus strains isolated from skin and catheter tips were related to specimens isolated from blood. A prospective observational study, carried out in a clinical surgical ward at a Brazilian hospital between September 2000 and November 2002, investigated non‐tunneled central venous catheters from 179 patients. S. aureus isolates were mainly obtained from blood (41.4%), while coagulase‐negative staphylococci strains were more often isolated from the skin at the catheter insertion site (49.7%) and from the catheter tip (57.5%). Among the 21 strains isolated from 9 patients at 2 or 3 sites simultaneously, 9 were methicillin‐resistant S. aureus (MRSA) and 12 were methicillin‐susceptible S. aureus (MSSA). Seven patients harbored the same S. aureus strain isolated from the skin, blood and/or catheter tip cultures. MRSA isolates belonged to one PFGE pattern (type A‐ subtypes A₁, A₂ and A₃), and to two rep‐PCR patterns (a and b). MSSA isolates were distinguished in five PFGE (B to F) and in three rep‐PCR (c, d and e) patterns. Both PFGE and rep‐PCR methods indicated that the skin at the catheter insertion site was the origin of CR‐BSI caused by S. aureus.     

Antinociceptive Effect of the Hydroalcoholic Extract of Bauhinia splendens Stems in Mice

The analgesic effect of the hydroalcoholic extract of the stems of Bauhinia splendens (Leguminosae) has been investigated in chemical and thermal models of nociception in mice. The hydroalcoholic extract of B. splendens, 3–60 mg kg^? intraperitoneally or 50–400 mg kg^? orally, caused dose-related, and long-lasting (up to 3 h) inhibition of acetic acid-induced abdominal constriction in mice, with ID50 values of 3.2 and 177.6 mg kg^? and maximum inhibition of 95 ± 2 and 61 ± 6%, respectively. In the formalin test, the extract given intraperitoneally (1.60 mg kg^?) or orally (50–400 mg kg^?) caused graded inhibition of both phases of formalin-induced pain, being about 5- to 6-fold more potent in attenuating the second phase of pain. The calculated mean ID50 values for the first and the second phases were 11.5 and 2.5 mg kg^?, respectively, for intraperitoneal administration and > 200 and 70 mg kg^?, respectively, for oral administration; the percentages of maximum inhibition for the first and the second phases were 68 ± 6 and 99 ± 1, respectively, for intraperitoneal administration and 37 ± 6 and 69 ± 9, respectively, for oral administration. However, at the same doses the extract did not significantly affect the oedematogenic response induced by formalin. The treatment of animals with naloxone (5 mg kg^?, i.p.) completely reversed the analgesic effect caused by morphine (5 mg kg^?, s.c), but had no effect against the antinociceptive effect of the hydroalcoholic extract of B. splendens (60 mg kg^?, i.p.) when assessed against acetic acid-induced abdominal constrictions. Furthermore, the extract, in contrast with morphine, had no analgesic effect in the hot-plate test. These data show that the hydroalcoholic extract of B. splendens has significant analgesic action when assessed against several models of pain. The mechanism underlying its analgesic effect still remains unknown, but seems to be unrelated to interaction with opioid systems.     

Analgesic Effects of Callus Culture Extracts from Selected Species of Phyllanthus in Mice

Abstract— The aim of this study was to evaluate the analgesic effect of the methanolic extract from callus culture of Phyllanthus tenellus, P. corcovadensis and P. niruri in several models of pain in mice. The extracts (medium containing 2,4-dichlorophenoxyacetic acid) of P. corcovadensis, P. niruri and P. tenellus (3–90 mg kg^?1, i.p.) caused graded inhibition of abdominal constrictions induced by acetic acid (0·6%), with ID50 (i.e. dose that reduced response of control by 50%) values of about 30, 19 and >30 mg kg^?1, respectively. The extract of callus of Phyllanthus obtained in indole-3-butyric acid and indole-3-acetic acid media (3–90 mg kg^?1, i.p.) caused a similar analgesic effect. In the formalin test, the extract of P. tenellus obtained in indole butyric acid medium (3–100 mg kg^?1, i.p.) inhibited only the second phase of formalin-induced pain with an ID50 value of about 100 mg kg^?1. Both the indole acetic acid and indole butyric acid methanolic extracts of P. tenellus and P. corcovadensis (10–100 mg kg^?1, i.p.) dose-dependently inhibited both phases of formalin-induced pain (ID50 values for the second phase were approx. 100 and 52 mg kg^?1, respectively). However, the extract of callus from Phyllanthus failed to affect formalin-induced paw oedema, as well as the response to radiant heat in the tail-flick test. In addition, the analgesic effect of morphine, but not the analgesic effects caused by Phyllanthus callus extract, was fully antagonized by naloxone. Preliminary phytochemical analysis revealed the presence of several compounds having no apparent relationship with alkaloids or flavonoids but showing the presence of phenols. These results indicate that, similar to previous reported data from the extract of P. corcovadensis, the methanolic extracts of callus culture of P. niruri, P. corcovadensis and P. tenellus exhibit potent analgesic properties against neurogenic and inflammatory pain that seem to be unrelated to the activation of opioid mechanisms.