Ex-vivo effect of intracanal medications based on ozone and calcium hydroxide in root canals contaminated with Enterococcus faecalis

A Novel Molecular Approach for Enhancing the Safety of Ozone in Autohemotherapy and Insights into Heme Pocket Autoxidation of Hemoglobin

Major ozone autohemotherapy (MAH) is a popular clinical practice for treating a variety of pathological conditions due to the mild and controlled oxidative stress produced by the reaction of ozone gas with other biological components. Previous studies have shown that blood ozonation leads to structural changes in hemoglobin (Hb); therefore, in the present study, the molecular effects of ozonation on Hb of a healthy individual were assessed by ozonating whole blood samples with single doses of ozone at 40, 60, and 80 μg/mL or double doses of ozone at 20 + 20, 30 + 30, and 40 + 40 μg/mL ozone to investigate whether ozonating once versus twice (but with the same final ozone concentration) would have varying effects on Hb. Additionally, our study aimed to verify whether using a very high ozone concentration (80 + 80 μg/mL), despite mixing it with blood in two steps, would result in Hb autoxidation. The pH, oxygen partial pressure, and saturation percentage of the whole blood samples were measured through a venous blood gas test, and the purified Hb samples were analyzed using several techniques including intrinsic fluorescence, circular dichroism and UV-vis absorption spectroscopies, SDS-polyacrylamide gel electrophoresis, dynamic light scattering, and a zeta potential analyzer. Structural and sequence analyses were also used to study the Hb heme pocket autoxidation sites and the residues involved. The results showed that the oligomerization and instability of Hb can be reduced if the ozone concentration to be used in MAH is divided into two doses. Indeed, our study demonstrated that two-step ozonation with 20, 30, and 40 μg/mL of ozone instead of single-dose ozonation with 40, 60, and 80 μg/mL of ozone reduced the potential adverse effects of ozone on Hb including protein instability and oligomerization. Moreover, it was found that for certain residues, their orientation or displacement leads to the entry of excess water molecules into the heme moiety, which can contribute to Hb autoxidation. Additionally, the autoxidation rate was found to be higher in alpha globins compared to beta globins.

The antimicrobial effect of different ozone protocols applied in severe curved canals contaminated with Enterococcus faecalis: ex vivo study

The aim of this study was to evaluate 3 different irrigation protocols using ozone on monoculture biofilm of Enterococcus faecalis. Fifty disto-buccal roots of maxillary first molars were instrumented up to the size 25.08, sterilized and then incubated with Enterococcus faecalis for 21 days for biofilm maturation in the root canal walls. After contamination, the initial collection (S1) was performed and the 50 samples were divided in 3 experimental groups (n = 15) and 1 positive control group (n = 5) as follows: Group1: Ozonated water (40 µg/ml); Group2: gaseous ozone (40 µg/ml); Group3: Ozonated water (40 µg/ml) under continuous ultrasonic irrigation (CUI) and, Group 4: 2.5% sodium hypochlorite (positive control). The final collection (S2) was performed using hedstroem files # 25 by scraping the root canal wall and absorbed paper cone. The collected samples were analyzed by CFU/ml count and qPCR. To compare the effect of irrigation methods and to investigate E. faecalis count data, Kruskal-Wallis and Wilcoxon nonparametric tests were used at p < 05. The values of the differences between the S1 values and the S2 values revealed that the groups did not differ significantly for either E. faecalis CFU count data (p = 0.713) or q-PCR (p = 0.185), however, it is observed that for all groups, the CFU count of E. faecalis decreased over 99%. For the q-PCR assay, the reduction was on the order of 74-95%. Only the NaOCl positive control group presented total elimination of CFU/mL bacterial counting. The ozone protocols assessed were similar in regard to Enterococcus faecalis reduction.

Immediate tooth replantation: root canal filling for delayed initiation of endodontic treatment

The aim of this study is to evaluate the action of paramonochlorophenol associated with Furacin followed by calcium hydroxide (CH) dressing in the control of inflammatory root resorption in cases of immediate tooth replantation with delayed endodontic treatment. A total of 28 incisors of 3 male dogs were extracted and replanted after 15 minutes, and randomly divided into 3 groups: Group I (n = 8) - endodontic treatment was performed before the extraction and replantation; Group II (n = 10) - endodontic treatment was performed 30 days after replantation and the root canal was filled with CH dressing; Group III (n = 10) - endodontic treatment was performed 30 days after replantation and root canals received temporary medication of paramonochlorophenol-Furacin followed by CH dressing. The animals were euthanized 90 days after replantation. The histomorphological events analyzed at the epithelial reattachment site were the intensity and extent of acute and chronic inflammatory processes, periodontal ligament (PDL) organization, the intensity and extent of acute and chronic inflammatory processes in the PDL space, root resorption, bone tissue, and ankylosis. Data were submitted to the Wilcoxon Signed Ranks Test for group comparison (α = 5%). In Groups I, II and III the periodontal ligament was regenerated and most of the resorption areas were repaired by newly formed cementum. The depth and extent of root resorption were significantly higher in Group II than in Group III. The use of paramonochlorophenol-furacin followed by CH dressing was more effective in controlling inflammatory root resorption after immediate tooth replantation.

The antibacterial effect of topical ozone on the treatment of MRSA skin infection

Skin can be infected by many types of microorganisms, most commonly by gram‑positive strains of Staphylococcus and Streptococcus spp. Treatment of Staphylococcus aureus (S. aureus) infections, particularly that of methicillin resistant Staphylococcus aureus (MRSA), is a challenge in clinical practice. Ozone therapy has proven to be one of the strongest antiseptics against the majority of microorganisms involved in skin infections. The purpose of the present study was to evaluate the microbicidal effects of topical ozone therapy on S. aureus and MRSA, and determine the clinical efficacy of ozone therapy on patients with MRSA skin infection. Microbicidal effects of ozonated oil and ozonated water were determined by plating and Kirby Bauer methods. Clinical efficacy and safety of topical ozone were evaluated in two cases with skin MRSA infection. The killing rates of ozonated oil for S. aureus and MRSA were greater when compared with the control oil group. Almost 100% of S. aureus were eliminated by ozonated oil following 5 min. Almost 100% MRSA were eliminated by ozonated oil following 15 min. In addition, 100% S. aureus and 100% MRSA were eliminated by ozonated water in 1 min. The inhibition zone diameters of ozonated oil for S. aureus and MRSA were 17 and 13 mm, respectively, which were significantly larger than the control group. Both cases of skin MRSA infection were completely healed with ozone therapy. In conclusion, ozone therapy is a potential treatment for S. aureus and MRSA skin infection as it has great efficacy, few side effects and low‑costs.

Evaluation of Microbial Reduction in Root Canals Instrumented with Reciprocating and Rotary Systems

OBJECTIVE

This in vitro study aimed to evaluate the efficacy of the disinfection of root canal systems carried out with Reciproc(TM) and ProTaper Universal(TM) systems using 1% sodium hypochlorite (NaOCl).

METHODS

Forty human single-rooted mandibular premolars were infected with Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans, and twenty were not infected. The specimens were randomly divided into 6 groups (n = 10): Group 1: ProTaper Universal(TM) + 1% NaOCl; Group 2 (positive control): ProTaper Universal(TM) + saline; Group 3 (negative control without microorganisms): ProTaper Universal(TM) + saline; Group 4: Reciproc(TM) + 1% NaOCl; Group 5 (positive control): Reciproc(TM) + saline; Group 6 (negative control without microorganisms): Reciproc(TM) + saline. Samples were collected before and after the completion of specific treatments, and plated in specific media cultures. The Fisher exact test was used for the statistical analysis of differences in terms of presence or absence of microbial growth among groups. For all tested pathogens, significant differences (p < 0.001) were verified between the instrumentation systems used.

RESULTS

ProTaper Universal(TM) associated with 1% NaOCl completely eliminated all microorganisms. Microbial growth, however, was observed when Reciproc(TM) was used associated with 1% NaOCl.

CONCLUSION

According to the protocol executed for this study, the Reciproc(TM) system associated with 1% NaOCl was not able to completely eliminate E. faecalis, P. aeruginosa, S. aureus and C. albicans from the root canal systems.

LPS levels in root canals after the use of ozone gas and high frequency electrical pulses

The present study aims to verify the effect of ozone gas (OZY® System) and high frequency electric pulse (Endox® System) systems on human root canals previously contaminated with Escherichia colilipopolysaccharide (LPS). Fifty single-rooted teeth had their dental crowns removed and root lengths standardized to 16 mm. The root canals were prepared up to #60 hand K-files and sterilized using gamma radiation with cobalt 60. The specimens were divided into the following five groups (n = 10) based on the disinfection protocol used: OZY® System, one 120-second-pulse (OZY 1p); OZY® System, four 24-second-pulses (OZY 4p); and Endox® System (ENDOX). Contaminated and non-contaminated canals were exposed only to apyrogenic water and used as positive (C+) and negative (C-) controls, respectively. LPS (O55:B55) was administered in all root canals except those belonging to group C-. After performing disinfection, LPS samples were collected from the canals using apyrogenic paper tips. Limulus Amoebocyte Lysate (LAL) was used to quantify the LPS levels, and the data obtained was analyzed using one-way ANOVA. The disinfection protocols used were unable to reduce the LPS levels significantly (p = 0.019). The use of ozone gas and high frequency electric pulses was not effective in eliminating LPS from the root canals.

In Vitro Alkaline pH Resistance of Enterococcus faecalis

Enterococcus faecalis is a bacterial species often found in root canals with failed endodontic treatment. Alkaline pastes are widely used in Endodontics because of their biocompatibility and antimicrobial activity, but this microorganism can resist alkalinity. The purpose of this study was to evaluate in vitro the alkaline pH resistance of E. faecalis for different periods up to 14 days. Samples were obtained from the oral cavity of 150 patients from the Endodontic clinic. The pH of the experimental tubes (n=84) was first adjusted with 6M NaOH to pH values of 9.5, 10.5, 11.5 and 12.5 (21 tubes per pH). Twenty clinical isolates and the ATCC 29212 strain were tested. The 5 positive controls and experimental tubes of each pH were inoculated with 10 µL of bacterial suspension and incubated at 36 °C for 24, 48 and 72 h, 7 and 14 days. For each period, the turbidity of the medium was visually compared with a 0.5 McFarland standard. The presence of the microorganism was confirmed by seeding on M-Enterococcus agar. Four tubes containing BHI broth adjusted to the tested pHs were incubated for 14 days to verify if pH changes occurred. The pH of inoculated BHI broth was also measured on day 14 to determine if the microorganism acidified the medium. The growth of all E. faecalis strains occurred at pH 9.5 to 11.5 in all periods. Although turbidity was not observed at pH 12.5, there was growth of 13 and 2 strains at 24 and 48 h, respectively, on M-Enterococcus agar. No tube showed growth at pH 12.5 after 72 h. It was concluded that E. faecalis can survive in highly alkaline pH, and some clinical isolates require 72 h at pH 12.5 to be killed.