Comparison of antibacterial and toxic effects of various root canal irrigants

AIM

To compare the antibacterial properties and toxicity of 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine gluconate and 0.2% chlorhexidine gluconate plus 0.2% cetrimide (Cetrexidin); Vebas, San Giuliano, Milan, Italy).

METHODOLOGY

The antibacterial effects of the irrigants in vitro were examined after 5 min and 48 h in freshly extracted human teeth with single roots, whose canals were infected by Enterococcus faecalis ATCC 29212. In a separate in vivo study, bacterial culture samples were collected before treatment from the infected root canals of deciduous teeth containing necrotic pulp tissue. Irrigants were used to clean the canals which were then left empty for 48 h. Aerobic/facultative anaerobic and anaerobic bacterial growth were compared before and 48 h after irrigation. Finally, the toxic effects of the irrigants were assessed by injecting them into the subcutaneous tissues of rats. The inflammatory reactions that occurred 2 h, 48 h and 2 weeks after the injections were evaluated.

RESULTS

In the laboratory study, the 2% chlorhexidine gluconate and Cetrexidin were significantly more effective on E. faecalis than the 5.25% NaOCl at 5 min (P < 0.05). Similarly, in the in vivo study, 2% chlorhexidine gluconate and Cetrexidin were significantly more effective on anaerobic bacteria than the 5.25% NaOCl at 48 h (P < 0.05). At the end of 2 weeks, the toxicity of the NaOCl solution was greater than that of the other irrigants (P < 0.05).

CONCLUSIONS

Cetrexidin and 2% chlorhexidine gluconate were more effective, and had more residual antibacterial effects and lower toxicity than 5.25% NaOCl solution.

Investigation of synergism of meropenem and ciprofloxacin against Pseudomonas aeruginosa and Acinetobacter strains isolated from intensive care unit infections

The aim of this study was to determine synergistic effects of meropenem and ciprofloxacin against Pseudomonas aeruginosa and Acinetobacter strains isolated from intensive care unit (ICU) infections. A total of 18 P. aeruginosa and 17 Acinetobacter strains were tested. MICs were determined using the broth microdilution method. The synergy of meropenem and ciprofloxacin was investigated in glass tubes using time-kill methodology. The synergistic effect of meropenem and ciprofloxacin in combination was found to be 22% at 0.5 x the MIC and 61% at 1 x the MIC in P. aeruginosa strains. Two strains (11%) showed synergy at both 0.5 and 1 x the MIC. Of the 18 P. aeruginosa strains, 1 strain (6%) did not show a synergistic effect at either 0.5 or 1 x the MIC. In Acinetobacter strains, the synergistic effect of meropenem and ciprofloxacin in combination was found to be 29% at 0.5 x the MIC and 18% at 1 x the MIC. One strain (6%) showed synergy at both 0.5 and 1 x the MIC. Of the 17 Acinetobacter strains, 8 strains (47%) did not show a synergistic effect at either 0.5 or 1 x the MIC. According to the results of this study, the combination of meropenem and ciprofloxacin is more effective than either antibiotic alone in ICU infections due to P. aeruginosa strains.

Expression of P fimbriae of uropathogenic Escherichia coli strains

The occurrence of P fimbriae in a total of 222 uropathogenic Escherichia coli (UPEC) strains was investigated. Out of the total, 31 (14%) were P fimbriated. Of 24 pyelonephritogenic E. coli strains, three (13%) with P fimbriae occurred in children with clinical pyelonephritis, and of 198 E. coli strains 29 (15%) occurred in children with cystitis. Prevalence of P fimbriae of E. coli strains was found to be quite similar in patients with cystitis and pyelonephritis

A new ancient irrigation therapy for childhood renal candidiasis

Methylene blue (MB) alone, MB metabolites in the urine and the effect of MB plus alkalization on Candida species were determined. MB was used for the treatment of childhood renal candidiasis (CRC) in 3 patients as an irrigating solution. Besides irrigation, fluconazole 3 mg/kg/day intravenously and MB 0.2 mg/kg/day were administered perorally. Urine cultures were cleared of Candida. DMSA scans obtained after 6 months showed no evidence of scarring. MB can be used for irrigation of the urinary tract, with fewer side effects than amphotericin B (AB). Additionally we advocate the use of ureteral catheters instead of nephrostomy in the treatment of CRC.

End-results of experimental gastroschisis created by abdominal wall versus umbilical cord defect

An experimental study was conducted to determine the end-results of two different defects on the anterior abdominal wall: an abdominal wall defect (AWD) versus an umbilical cord defect (UCD) using chick embryos. The AWD was created by leaving an intact skin bridge between the defect and the umbilical cord in group 1; the UCD was created on the umbilical cord near the junction of the skin in group 2. At the end of incubation, the intestines appeared hemorrhagic in the AWD group, but not in the UCD group. During microscopic examination, hemorrhagic areas were observed in the bowel wall and mucosal villi in the AWD group but not in the UCD group. The end-result of the defect causing the physiological umbilical hernia resulted in bowel damage resembling the classic picture of gastroschisis (GS). We conclude that the site of the defect in GS is not the abdominal wall itself, but the physiological umbilical hernia.

Initial evaluation of children sustaining blunt abdominal trauma: ultrasonography vs. diagnostic peritoneal lavage

A prospective clinical study was performed to compare ultrasonography (US) with a modality having 96-99% accuracy like diagnostic peritoneal lavage (DPL) to find the accuracy of US in the initial evaluation of children sustaining blunt abdominal trauma (BAT). Sixty-eight children with BAT were initially evaluated by US, then DPL. All patients with pathologic US findings underwent computerized tomographic examination before DPL to confirm the pathologies. Through US examination free intraperitoneal fluid (FIF) was present in eleven, absent in 57 patients. DPL was positive in ten, negative in 58 patients. Sensitivity, specificity, negative predictive value, positive predictive value and efficiency of US were 100, 98.3, 100, 91 and 98.5 respectively. US detected intraperitoneal solid organ injuries in eleven patients, but DPL was positive in only ten of these patients. While US detected renal injuries in six patients and intrapleural fluid in two patients, DPL was positive in only two of these patients as a result of concomitant intraperitoneal solid organ injuries with FIF. The present study has shown that US can detect FIF with a high rate of accuracy comparable to DPL in children. In addition, US has advantages over DPL in the detection of intraperitoneal organ injuries with or without concomitant FIF, retroperitoneal injuries and intrathoracic injuries. Thus US is thought to be superior to DPL and recommended as a routine first choice screening tool in the initial evaluation of children sustaining BAT.

Outpatient catheterless Mathieu repair: how to cover ventral penile skin defect

A modification of the Mathieu repair eliminating stenting has been described by Rabinowitz which makes the method more convenient for outpatient performance. We report on our experience with this modification with special emphasis on coverage of ventral penile skin defect. To cover the raw area formed on the ventral aspect of penis with the creation of meatal based flap Rabinowitz used Byar's flap. Two different flaps prepared from prepuce were used in this series. In some patients an island flap was used. In others the prepuce was incised transversally on its dorsal aspect and transferred to the ventral surface as a bipedicle visor flap, as described by Ombrédanne and popularized by Nesbit. Twenty-two patients ranging in age from one to twelve years (mean +/- 1SD = 6 +/- 3.28) were operated on using the technique. The meatus was glandular in two, coronal in twelve and distal penile in eight patients. Preputial flap was not used in one patient because the defect was small. Island flap was used in three and Ombrédanne-Nesbit's flap in 18 patients. Complete disruption of the repair occurred in one of the patients in whom an island flap was used. Among 18 patients in whom Ombrédanne-Nesbit's flap was used, one partial necrosis of the preputial flap was encountered which required revision and two urethrocutaneus fistulae occurred which healed spontaneously. The use of the present technique yields a good cosmetic result, a high success rate with minimal complications, and eliminates catheterization; hence, hospitalization is recommended.