Effectiveness of stannous fluoride and calcium hydroxide against Enterococcus faecalis

Antimicrobial evaluation of polytetrafluoroethylene used as part of temporary restorations: An ex vivo study

The use of polytetrafluoroethylene (PTFE) tape as the base layer of temporary restorations had gained popularity mainly due to the ease of manipulation. The aim of this study was to assess whether this method changes the potential for bacterial growth and leakage of temporary restorations. The direct contact test and live/dead fluorescent staining were used for comparing Enterococcus faecalis growth and biofilm formation on PTFE, composite, intermediate restorative material (IRM) and Coltosol F. Confocal laser scanning microscopy was employed to evaluate E. faecalis penetration through 2 mm of PTFE, IRM or Coltosol F placed on the bottom of the pulp chamber and into radicular dentinal tubules in extracted maxillary third molars. The results demonstrated that E. faecalis grows on and penetrates through PTFE significantly more than it does with IRM and Coltosol F, revealing its comparably reduced overall antimicrobial sealing ability when placed as the base part of temporary restorations.

Antibacterial Efficacy of Casein Phosphopeptide-Amorphous Calcium Phosphate Compared to Calcium Hydroxide as Intracanal Medicaments against Enterococcus faecalis: In-vitro Study

Background:

Endodontic infection may persist despite root canal instrumentation. Thus, the use of intracanal medicaments plays an essential role in eliminating resistant bacteria like Enterococcus faecalis, known to be associated with persistent infections in endodontically treated teeth. Although calcium hydroxide is the gold standard intracanal medicament, it has been reported that Enterococcus faecalis is immune to its effects. Therefore, several studies assessed the efficacy of other intracanal medicaments, but none to date evaluated Casein Phosphopeptide-Amorphous Calcium Phosphate.

Objectives:

This in-vitro randomized controlled study aimed to assess the antibacterial efficacy of Casein phosphopeptide-amorphous calcium phosphate as an intracanal medicament against Enterococcus faecalis and compared it to calcium hydroxide.

Methods:

60 extracted single root canal permanent teeth were prepared and later divided into three equal groups according to the intracanal medicament used. Group 1: No intracanal medicament (negative control), Group 2: Calcium hydroxide paste, and Group 3: Casein phosphopeptide-amorphous calcium phosphate paste. The intracanal medicaments were placed on the canals for 7 days. The outcome of this procedure was measured by counting colony-forming units. Statistical analysis was carried out using One-Way ANOVA and Tukey’s Post Hoc Test to determine significant differences between the groups.

Results:

The mean bacterial count for Group 2 was significantly lower than Group 1 and Group 3. Calcium hydroxide showed significantly more antibacterial efficacy against Enterococcus faecalis than Casein phosphopeptide-amorphous calcium phosphate and the negative control groups.

Conclusion:

Casein Phosphopeptide-amorphous calcium phosphate is ineffective in inhibiting Enterococcus faecalis growth compared to Calcium hydroxide.

Direct pulp capping of primary molars using a novel fast-setting calcium silicate cement: a randomized clinical trial with 12-month follow-up

Objective: Novel fast-setting calcium silicate cement with fluoride (Protooth) has been developed for potential applications in tooth crowns. The aim of this study was to evaluate the success rate of direct pulp capping in primary molars using two-layer mineral trioxide aggregate (MTA) and overlying glass ionomer cement versus one-layer novel calcium silicate cement with 4 to 10 minutes setting time. Materials and methods: Ninety bilaterally symmetrical primary molars in the same jaw in 45 patients aged 5 to 7 years were included. Exposed pulps following caries removal were randomly capped with one-layer novel calcium silicate cement or two-layer MTA and glass ionomer cement. All cavities were filled with amalgam. Clinical and radiographic evaluations were performed after six and twelve months. 41 patients were available for the evaluations at the end of the 12-month follow-up. Results: The overall success rate of direct pulp capping, in a split-mouth design, using MTA covered with glass ionomer cement or one-layer novel calcium silicate cement after 12 months were 90% (37 out of 41 cases) and 85% (35 out of 41 cases), respectively, without statistically significant differences after 6 and 12 months. Conclusion: Within the limitations of this study, clinical and radiographic evaluations suggested one-layer novel calcium silicate cement would be successfully used in direct pulp capping of primary molars as a practical alternative to two-layer MTA and overlying glass ionomer cement.

Antimicrobial activity and pH measurement of calcium silicate cements versus new bioactive resin composite restorative material

Background

The purpose of this in vitro study is to compare the antimicrobial effect and pH of two calcium silicate cements Mineral trioxide aggregate high plasticity (Angelus PR, Brazil) and iRoot BP Plus (BioCeramix Inc., Vancouver, BC, Canada) and new bioactive restorative resin composite restorative material (ACTIVA, MA, Pulpdent, USA) against aerobic bacteria, strictly anaerobic bacteria and a yeast by using an agar diffusion test.

Methods

The materials were tested immediately after manipulation and were applied to the agar plates. Sodium hypochlorite (NaOCl) 5.25% was used as a positive control group. The dry filter paper acted as a negative control group for this study. The size of the inhibition zone for each material was measured after 12, 24 and 48 h. At the time of pH measurement; materials were prepared, crushed then dispersed in distilled water.

Results

The one-way Anova test revealed that iRoot BP Plus significantly showed superior antimicrobial efficacy compared to MTA-HP against the following species; Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis, Enterococcus faecium, Peptostreptococcus anaerobius and Candida albicans (P < 0.05). All of the tested materials did not show any antimicrobial effect against Porphyromonas gingivalis and Actinomyces israelii. The new bioactive resin composite material (ACTIVA) showed the least antimicrobial activity against the previously mentioned microorganisms except E. faecalis. NaOCl significantly showed the highest antimicrobial activity among the test group (P < 0.05). iRoot BP Plus was more alkaline (pH 12.1 ± 0.14/ 11.9 ± 0.25) in comparison to MTA-HP (pH 11.6 ± 0.16/ 11.2 ± 0.10) while ACTIVA was slightly acidic (pH 5.4 ± 0.09/ 6.5 ± 0.08).

Conclusions

According to the findings of this study, it was concluded that calcium silicate- based cements showed a potential antimicrobial activity mainly due to its high alkalinity. The new bioactive resin composite restorative material exhibits less antimicrobial activity due to its resinous ingredients and slightly acidic nature. Antimicrobial effect of calcium silicate cements against strictly anaerobic bacterial species is still questionable.

Ion release by endodontic grade glass-ionomer cement

Cylindrical specimens (6 mm high x 4 mm diameter) of the endodontic grade glass-ionomer (Ketac Endo) were exposed to various media for 1 week, after which changes in their mass, pH of storage medium, and ion release were determined. In water, this cement was shown to release reasonable amounts of sodium, aluminium and silicon, together with smaller amounts of calcium and phosphorus, as well as taking up 2.41% by mass of water. A comparison with the restorative grade materials (Ketac Molar, ex 3M ESPE and Fuji IX, ex GC) showed both ion release and water uptake to be greater. All three cements shifted pH from 7 to around 6 with no significant differences between them. Other storage media were found to alter the pattern of ion release. Lactic acid caused an increase, whereas both saturated calcium hydroxide and 0.6% sodium hypochlorite, caused decreases. This suppression of ion-release may be significant clinically. Aluminium is the most potentially hazardous of the ions involved but amounts released were low compared with levels previously reported to show biological damage.

Antimicrobial effect, in vitro, of gutta-percha points containing root canal medications against yeasts and Enterococcus faecalis

OBJECTIVE

The objective of this study was to determine the in vitro susceptibility of Enterococcus faecalis and the most prevalent Candida species as therapy-resistant microorganisms to gutta-percha points containing root canal medications.

STUDY DESIGN

Gutta-percha points containing calcium hydroxide (Calcium Hydroxide Plus Points), chlorhexidine diacetate (Activ Points), or calcium hydroxide-chlorhexidine combinations (CHX/Ca Combi Points) were tested for their ability to inhibit growth of pure cultures of Candida albicans, Candida glabrata, Candida parapsilosis, Candida krusei, Candida tropicalis, Saccharomyces cerevisiae, and Enterococcus faecalis. Approximately 2 x 10(7) microorganisms per assay were suspended in diluted human serum and co-incubated with the gutta-percha points placed in Eppendorf tubes in an incubator for up to 2 weeks. A tube was removed at 1, 2, 3, 4, 7, and 14 days, and then opened and microorganism suspensions were serially diluted in a sterile 0.9% NaCl solution. Aliquots of the dilution steps were streaked onto solid medium. After incubating the plates in an incubator at 37 +/- 1 degrees C for 48 hours, CFU numbers per milliliter of suspension were calculated.

RESULTS

Calcium Hydroxide Plus Points or Activ Points did not exhibit sufficient antimicrobial or anticandidal activity for Enterococcus faecalis, Candida albicans, C. glabrata, C. parapsilosis, C. krusei, or C. tropicalis within 14 days. Only Saccharomyces cerevisiae was susceptible to the calcium hydroxide or chlorhexidine diacetate containing gutta percha points. CHX/Ca Combi Points killed C. albicans, C. glabrata, C. krusei, C. tropicalis, and S. cerevisiae completely. However, E. faecalis and C. parapsilosis were resistant to CHX/Ca Combi points within 14 days.

CONCLUSION

The results show the gutta percha points containing a mixture of calcium hydroxide and chlorhexidine diacetate have efficacies superior to calcium hydroxide or chlorhexidine diacetate alone against some microorganisms except E. faecalis and C. parapsilosis.

An In Vitro Evaluation of the Antibacterial Efficacy of Chlorine Dioxide on E. faecalis in Bovine Incisors

This study investigated the ability of chlorine dioxide to eliminate Enterococcus faecalis from dentinal tubules of bovine incisors. Thirty-seven extracted bovine incisor roots were sectioned into seventy-four 5 mm disks. Standardized lumens were filled with either sterile Brain Heart Infusion Broth (contamination controls, n = 10) or BHI containing E. faecalis (1.0 x 10 cfu/ml). Disks were incubated in 5% CO2 at 37 degrees C for 72 h. To simulate endodontic instrumentation the lumens were again enlarged. Sixty disks were randomly divided into four experimental groups and filled with one of the following irrigants: 10% Clidox-S (chlorine dioxide), 13.8% BioClenz (chlorine dioxide), 5.25% Clorox, or saline. The disks were incubated for 30 min and were then frozen, pulverized, serially diluted in phosphate buffered saline, and plated on BHI plates in triplicate. Total colony forming units were counted macroscopically. Statistical analysis of the data was performed with a Kruskal-Wallis one-way ANOVA on ranks (p < 0.05, n = 60). Bacterial counts, expressed in log10 cfu/disk were as follows (">" denotes significant differences): Saline > Clidox-S = BioClenz > Clorox. All negative controls were sterile. Chlorine dioxide and NaOCL were both effective in eliminating E. faecalis from the dentinal disks within 30 min.

Antibacterial Efficacy of Calcium Hydroxide and Chlorhexidine Gluconate Irrigants at 37°C and 46°C

This study investigated the ability of two endodontic irrigants to eliminate Enterococcus faecalis from dentinal tubules, and whether their antimicrobial action was enhanced by heat. The lumens of disks prepared from extracted bovine roots were infected with E. faecalis and incubated for 72 h. Specimens were then filled with saline, 10% calcium hydroxide (Ca(OH)2), or 0.12% chlorhexidine gluconate (CHX) at 24 degrees C or 46 degrees C and incubated at 37 degrees C or 46 degrees C. The samples were then pulverized and plated to quantify residual bacteria. No statistical difference (p > 0.05) in bacterial growth was seen between the two saline groups, or between the two medication groups at a given temperature. CHX and Ca(OH)2 at either temperature produced significantly less growth than either saline group, and CHX or Ca(OH)2 at 46 degrees C produced significantly less growth than either group at 37 degrees C. Heat enhanced the antibacterial action of both experimental irrigants against E. faecalis, but heating saline produced no increase in bactericidal effect.