Sodium Hypochlorite Group Research Articles

Adhesion to pulp chamber dentin: Effect of different endodontic irrigants

Aim: To evaluate the effect of different endodontic irrigation regimens on the sealing ability of resin composite restorations placed within the pulp chamber using contemporary simplified adhesives. Materials and Methods: Seventy-five extracted human molars were divided into six groups. After de-roofing the pulp chamber and extirpating the pulp, pulp chambers were bonded with either G-Bond after irrigation with saline (Group 1); ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl) (Group 2), and NaOCl + QMix (Group 3) or bonded with OptiBond adhesive after irrigation with saline (Group 4), EDTA and NaOCl (Group 5), and NaOCl + QMix (Group 6). All the samples were restored with composite. Ten samples per group were assessed for dye penetration. Fifteen samples were assessed under scanning electron microscope. Data were statistically analyzed using Mann–Whitney and Kruskal–Wallis tests at a significance level of P < 0.05. Results: Both EDTA + NaOCl or NaOCl + QMix pretreatment of pulp chamber dentin significantly reduced microleakage scores in adhesive OptiBond, but did not affect the microleakage of G-Bond. Conclusions: EDTA + NaOCl or NaOCl + QMix irrigation of the pulp chamber was not deleterious to the bonding of any of the adhesives tested.

Evaluation of Effects on the Adhesion of Various Root Canal Sealers after Er:YAG Laser and Irrigants Are Used on the Dentin Surface

IntroductionThe aim of this study was to evaluate the bond strength of various root canal sealers after various irrigation solutions and Er:YAG laser irradiation were used on root canal dentin. MethodsOne hundred fifty freshly extracted human maxillary single-rooted teeth were used in this study. Teeth were sectioned transversally 4 mm below the cementoenamel junction. The root canal of each specimen was prepared using a tapered bur. Teeth were divided into 3 main groups by sealer (AH Plus Jet [Dentsply DeTrey, Konstanz, Germany], EndoSequence BC Sealer [Brasseler, Savannah, GA], and Real Seal [SybronEndo, Orange, CA]) and then divided into 5 subgroups by dentin treatment (distilled water, calcium hydroxide, sodium hypochlorite, EDTA, and Er:YAG laser). The specimens were placed immediately at 37°C and 100% humidity for 1 week. Then, the push-out test was applied. The maximum failure load was recorded in newtons and was used to calculate the push-out bond strength in MPa. Then, 3 random specimens from each group were examined under scanning electron microscopy. ResultsThe resin root canal sealers had higher push-out bond strength than the bioceramic sealer, and the differences were statistically significant (P < .05) except in the sodium hypochlorite groups. The EDTA and Er:YAG laser applications removed the smear layer and increased the bond strength. The highest adhesion was observed in EDTA groups when each sealer was evaluated in itself. ConclusionsThe bonding strength of root canal sealers is influenced by their properties and various dentin surface treatments. The scanning electron microscopic study showed that although the dentinal tubules were open, at the profile examination the sealers did not penetrate into the dentin canals in all specimens.

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The purpose of this study was to evaluate the impact of different disinfection solutions on flexural resistance of chemically-activated acrylic resin. Test pieces were made of clear acrylic resin using a rectangular mold and employing two techniques: wet polymerization under pressure (n = 20) and dry polymerization under pressure (n = 20). Test pieces were subdivided into four equal groups: distilled water (control), sodium bicarbonate, 1% sodium hypochlorite and effervescent ats. The 30-day cycling technique consisted of immersing the test pieces in 100 ml of solution for 10 min three times a day and placing them in closed containers containing artificial saliva at 37°C. Subsequently, the flexural resistance of samples was tested. Data were analyzed using two-way analysis of variance (ANOVA) with forces serving as the dependent variables and the polymerization technique and cleaning agents as independent variables. Post hoc multiple comparisons were performed using Tukey’s test. There was no statistically significant difference in the flexural strength between the two polymerization techniques. The greatest flexural strength was observed for the effervescent tablets group followed by the control and 1% sodium hypochlorite groups which were statistically similar. Thus, the sodium bicarbonate solution caused the lowest flexural resistance of the test pieces. Key words: Polymethyl methacrylate, material resistance, disinfection, orthodontic appliances.

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This study evaluated the effect of disinfectants on the tensile bond strength of Nickel-Chromium alloy bonded with resin cement. 180 pairs of Nickel-Chromium dumbbells were prepared. The dumbbells were divided into 3 groups (n=60), which received one of the following treatments: Sandblasted only (control), sandblasted and Perform (R)-ID or sandblasted and sodium hypochlorite (SH) before bonding with resin cement. All bonded specimens were stored in distilled water for 24 h and half of the specimens were subsequently thermocycled (500 cycles) before debonding. Tensile bond strength was recorded and each dumbbell was examined for failure mode. Two-way ANOVA analysis indicated that overall there was a statistically significant difference between 24 h and thermocycling test, but no differences between sandblasted only, sandblasted and Perform-ID or sandblasted and SH groups. Post-ANOVA contrasts indicated that only the sandblasted and SH group showed a significant difference between the 24 h and thermocycling test. Disinfectants did not significantly decrease tensile bond strength between Nickel-Chromium dumbbells bonded with resin cement.

Biofilm forming capacity of Enterococcus faecalis on Gutta-percha points treated with four disinfectants using confocal scanning laser microscope: An in vitro study.

Background:The aim of this study was to evaluate and compare the in vitro biofilm forming capacity of Enterococcus faecalis on Gutta-percha points disinfected with four disinfectants.Materials and Methods:A total of 50 Gutta-percha points used in this study were divided into four test groups based on disinfectant (5.25% sodium hypochlorite, 2% chlorhexidine gluconate, 20% neem, 13% benzalkonium chloride [BAK]), and one control group. The Gutta-percha points were initially treated with corresponding disinfectants followed by anaerobic incubation in Brain Heart Infusion broth suspended with human serum and E. faecalis strain for 14 days. After incubation, these Gutta-percha points were stained with Acridine Orange (Sigma – Aldrich Co., St. Louis, MO, USA) and 0.5 mm thick cross section samples were prepared. The biofilm thickness of E. faecalis was analyzed quantitatively using a confocal scanning laser microscope. Results statistically analyzed using analysis of variance. P < 0.05 was considered to be significant.Results:Confocal scanning laser microscope showed reduced amount of E. faecalis biofilm on Gutta-percha points treated with BAK and sodium hypochlorite. Post-hoc (least square differences) test revealed that there is no statistically significant difference between BAK and sodium hypochlorite groups (P > 0.05).Conclusion:This study illustrates that the Gutta-percha points disinfected with sodium hypochlorite and BAK showed minimal biofilm growth on its surface.

An in vitro evaluation of calcium hydroxide medication removal using various irrigants and methods

Aims: It is necessary to clean the dentine wall of smear layer, debris, and intra-canal medicament prior to obturation. Any residual intra-canal medicament interferes with the sealing ability of root canal sealers to the root dentine. Hence, effective and complete removal of calcium hydroxide intra-canal medicament is an important aspect in endodontic therapy. Settings and Design: Forty-four single rooted mandibular premolars were selected. After access cavity preparation and coronal enlargement, working length was established at 1 mm short of the apical foramen. Two negative samples served as the control group and the remaining teeth were filled with calcium hydroxide powder. Materials and Methods: The removal of this medicament was attempted by 0.5% sodium hypochlorite (Group I), 17% ethylenediaminetetracetic acid in combination with sodium lauryl sulfate (Group II), mechanical agitation with CanalBrush (Group III), use of master apical file (Group IV) and passive ultrasonic irrigation (Group V). The teeth were sectioned and visualized under a scanning electron microscope and analyzed using graded scoring criteria. Statistical Analysis Used: The statistical analysis was performed using Kruskal-Wallis and Mann-Whitney test. Results: Activated irrigation technique, that is, passive ultrasonic irrigation proved more effective than syringe irrigation. Conclusions: Although no single material or technique removed calcium hydroxide completely, a combination of techniques and solutions shall prove beneficial.

Evaluation of Effect of Different Cavity Disinfectants on Shear Bond Strength of Composite Resin to Dentin using Two-Step Self-Etch and One-Step Self-Etch Bonding Systems: A Comparative in vitro Study

To evaluate the effect of 2% chlorhexidine, 2% sodium hypochlorite, 3% hydrogen peroxide on shear bond strength of composite resin to dentin using two-step and onestep self-etch bonding systems and to study the mode of failure of specimens under stereomicroscope. Eighty extracted sound human posterior teeth were used. The occlusal surfaces were ground to expose the dentin and were then randomly divided into 4 main groups. In group I, no cavity disinfectant was used and served as control. In groups II, III, IV, 2% chlorhexidine, 2% sodium hypochlorite and 3% hydrogen peroxide were used as cavity disinfectants respectively. Each group was then divided into two subgroups of 10 teeth each according to the bonding agent used, two-step self-etch (Adper SE Plus) and one-step self-etch (Adper Easy One) respectively. A transparent cylindrical plastic tube was loaded with microhybrid composite and placed over the dentin and light cured for 40 seconds. The specimens were subjected to shear stress in the universal testing machine. Pretreatment with 2% chlorhexidine, 2% sodium hypochlorite and 3% hydrogen peroxide, had a negative effect on the shear bond strength of self-etching bonding systems. The highest bond strength was found in 2% chlorhexidine group followed by 2% sodium hypochlorite group and the lowest bond strength was found in 3% hydrogen peroxide group. All three cavity disinfectants used in this study reduced the shear bond strength and hence should be used with caution.

A histopathological comparison of pulpotomy with sodium hypochlorite and formocresol.

Formocresol is widely used in primary teeth pulpotomies; however it is known to have several side effects. The purpose of this study was to assess pulpal changes of primary teeth pulps after pulpotomy with sodium hypochlorite and formocresol. In this randomized clinical trial, 22 teeth were selected. These teeth were randomly divided into 2 groups (formocresol; n=11 and sodium hypochlorite n=11). Two months post-operatively teeth were extracted and pulpal responses were evaluated by recording the degree of inflammation and extent of pulpal involvement. Dentinal bridge formation was also evaluated. Finally the data was analyzed with McNemartest. The formocresol group demonstrated mild inflammation in 4 cases whereas sodium hypochlorite had mild inflammation in six cases. Severe inflammation was only found in 1 case in the sodium hypochlorite group, but it was present in 4 cases in the formocresol group. In sodium hypochlorite group there were no cases of necrosis, and dentinal bridge was found in 3 cases, unlike, the formocresol group which had necrosis but no dentinal bridge formation. Based on the results of this study sodium hypochlorite may be a suitable solution for conducting pulpotomy in primary teeth.

Faster Wound Healing With Topical Negative Pressure Therapy in Difficult-to-Heal Wounds

A randomized clinical trial was conducted to determine the effectiveness and safety of topical negative pressure therapy in patients with difficult-to-heal wounds. A total of 24 patients were randomly assigned to either treatment with topical negative pressure therapy or treatment with conventional dressing therapy with sodium hypochlorite. The study end point was 50% reduction in wound volume. The maximum follow-up time was 6 weeks. The median treatment time to 50% reduction of wound volume in the topical negative pressure group was 2.0 weeks (interquartile range = 1) versus 3.5 weeks (interquartile range = 1.5) in the sodium hypochlorite group (P < 0.001). The unadjusted hazard rate ratio for the time until 50% wound volume reduction was 0.123 (P < 0.001). After adjustment for relevant baseline characteristics in a Cox proportional hazards model treatment group, membership was found as the only and statistically significant indicator for the time to 50% wound volume reduction (hazard rate ratio of 0.117 [P < 0.001]). Subgroup analysis of spinal cord injured patients with severe pressure ulcers showed similar statistically significant results as in the total wound group. Topical negative pressure resulted in almost 2 times faster wound healing than treatment with sodium hypochlorite, and is safe to use in patients with difficult-to-heal wounds.

Comparative evaluation of the effect of cavity disinfectants on the fracture resistance of primary molars restored with indirect composite inlays: An in vitro study

A study was conducted to evaluate and compare the effect of cavity disinfectants on the fracture resistance of primary molars restored with indirect composite inlays. Thirty-six non-carious primary second molars were selected and divided randomly into three groups (n = 12): control group (no disinfectant), chlorhexidine group (disinfected with 2% chlorhexidine for 40 seconds) and sodium hypochlorite group crowns (disinfected with 2% chlorhexidine for 40 seconds). The inlays were fabricated by indirect method using Ceram X nanocomposite on plaster die. All the groups were submitted to compression mechanic test in a Hounsfield universal testing machine at 1 mm/min cross-head speed and the results were calculated in Newtons. Descriptive statistics, independent t test, and one way analysis of variance (ANOVA) test revealed the mean fracture resistance of three groups, i.e., control group, chlorhexidine group and sodium hypochlorite group to be 2260.66, 1858.08 and 1310.66, respectively. When intragroup comparisons were made, a significant difference was observed in all the groups (P<0.001). Scheffe's post hoc test revealed that control group had the highest fracture resistance, followed by chlorhexidine group, and sodium hypochlorite group had the least fracture resistance. Each value differed significantly from the other (P<0.05). Cavity disinfectants used in the present study had detrimental effect on the fracture resistance of primary molars. Among the disinfectants employed in the present study, chlorhexidine showed a better resistance to fracture than sodium hypochlorite.

Efficacy of various root canal irrigants on removal of smear layer in the primary root canals after hand instrumentation: A scanning electron microscopy study

The purpose of this in-vitro study is to determine the efficacy of various irrigants in removing the smear layer in primary teeth root canals after hand instrumentation. The present study consisted of 30 human primary incisors which were sectioned at the cementoenamel junction horizontally. The specimens were divided randomly into four experimental and one control group having six teeth each and each group was treated with the specific irrigant. 5.25% NaOCl, 5.25% NaOCl + 10% EDTA, 6% citric acid, 2% chlorhexidine, saline (control) were the irrigants evaluated for efficacy in removal of smear layer. The specimens were split along the longitudinal axis using a chisel after placing superficial grooves in cementum not extending to the root canal. The exposed surface was subjected to scanning electron microscopic analysis to reveal the efficacy of irrigants in removal of smear layer. The representative areas were evaluated twice at 15 days interval by a single evaluator. The scale for the smear layer removal by Rome et al was modified and used in the present study. The pictures from the scanning electron microscopy showed that among the tested irrigants, citric acid has the best efficacy to remove the smear layer without altering the normal dentinal structures, which was supported by the lowest mean smear scores. The pictures from the 10%EDTA + 5.25% sodium hypochlorite group showed that even though it removed the smear layer, it adversely affected the dentine structure. SEM pictures of the other groups like sodium hypochlorite, chlorhexidine revealed that these irrigants does not have the capacity to remove the smear layer in primary teeth. The results of the present study clearly indicate the superior efficacy of 6% citric acid than the other tested irrigants on removing the smear layer in primary teeth root canals.

Bactericidal effect of KTP laser irradiation against Enterococcus faecalis compared with gaseous ozone: an ex vivo study

The objective of this study was to evaluate the antimicrobial activity of potassium-titanyl-phosphate (KTP) laser and gaseous ozone in experimentally infected root canals. Eighty single-rooted teeth with straight canals were selected. After preparation and sterilization, the specimens were inoculated with 10 microL Enterococcus faecalis for 24 hours at 37 degrees C. The contaminated roots were divided into 2 experimental groups, 1 negative control group, and 1 positive control group of 20 teeth each: Group 1, KTP laser group; Group 2, gaseous ozone group; Group 3, sodium hypochlorite group (NaOCl) (negative control); and Group 4, saline group (positive control). Sterile paper points used to sample bacteria from the root canals were transferred to tubes containing 5 mL of brain heart infusion broth. Then 10-microL suspension was inoculated onto blood agar plates. The colonies of bacteria were counted and data were analyzed statistically using Kruskal-Wallis 1-way analysis of variance and Mann-Whitney U tests. There were statistically significant differences between all groups (P < .05). The saline group had the highest number of remaining microorganisms. Complete sterilization was achieved in the 2.5% NaOCl group. The KTP laser and gaseous ozone did not completely sterilize the root canals. Both KTP laser and gaseous ozone have a significant antibacterial effect on infected root canals, with the gaseous ozone being more effective than the KTP laser. However, 2.5% NaOCl was superior in its antimicrobial abilities compared with KTP laser and gaseous ozone.

Ultrasonically nebulised electrolysed oxidising water: a promising new infection control programme for impressions, metals and gypsum casts used in dental hospitals

Controlling the transmission of infectious diseases by impressions, metals and dental casts in dental hospitals remains a challenge. Current disinfection methods have various drawbacks. This study introduced and provided a preliminary evaluation of the feasibility of using ultrasonically nebulised, electrolysed oxidising water (UNEOW) as a new infection control programme. UNEOW was produced from freshly generated electrolysed oxidising water (EOW). Samples of impressions, titanium and gypsum were subjected to the following treatments: (1) immersion in 1% sodium hypochlorite for 10min; (2) immersion in EOW for 10min; (3) exposure to UNEOW for 15, 30 and 45min; (4) no disinfection (control). Bactericidal efficacy was examined using Staphylococcus aureus and Bacillus subtilis var. niger spores as indicators. Dimensional accuracy, surface quality, and effect of corrosion were also evaluated for the different samples. Results showed that except for B. subtilis var. niger spores on gypsum casts, the bacterial reduction log(10) values after 30-45min treatment with UNEOW were all above 4. The impression dimensional changes showed no difference between control and UNEOW groups, but both were significantly lower than the EOW and sodium hypochlorite groups (P<0.05). The same was true for the surface quality of impressions and gypsum casts. No assessable corrosion was found on the titanium surface after a 45min treatment with UNEOW. The findings indicated that use of UNEOW is a feasible and promising approach for controlling the transmission of infectious diseases by impressions, gypsum casts and denture metals in dental facilities.