Microhardness Of Root Canal Dentin Research Articles

Impact of Chitosan as Chelating Agent on Microhardness and Mineral Content of Intraradicular Dentin

Aim: This study was designed to evaluate the effects of 0.2% chitosan, 2% chitosan and 17% EDTA chelating agents on the microhardness and mineral content of human root canal dentin. Materials and Methods: Sixty extracted single-rooted human teeth were longitudinally sectioned into 120 segments. The specimens were randomly divided into four groups according to the chelating agent used; G1: 0.2% chitosan, G2: 2% chitosan, G3: 17% EDTA and G4: saline (control group). Dentin microhardness was measured in a total of 80 specimens using Vickers diamond indenter with 300 g loadand a dwell time of 20 s. A total volume of 5 mL of each solution was used for 3min and then specimens finally flushed with 10 mL distilled water. In a total of 40 specimens, the level of three elements (calcium, phosphorus and magnesium) in each specimen was analyzed using inductively coupled plasma atomic emission spectrometry (ICPAES).Results: All tested chelating agents significantly decreased the microhardness of root canal dentin (P ≤ 0.05) and reduced the mineral content of dentin. Chitosan 2% and 17% EDTA had the statistically significant highest mean percentage reduction in microhardness compared to the control group (P ≤ 0.05) and showed the maximum loss of Ca ions from root canal dentin. Chitosan 0.2% showed less reduction in dentin microhardness and chelated Ca ions from root dentin. Conclusions: Chitosan 0.2% solution is equally effective to 17% EDTA in removing Ca ions from root canal dentin withoutmuch altering its microhardness. Accordingly, the natural product of 0.2% chitosan attracts its use as dentin chelating agent.

Effect of EDTA, Sodium Hypochlorite, and Chlorhexidine Gluconate with or without Surface Modifiers on Dentin Microhardness

IntroductionThis study aimed to evaluate the effects of root canal irrigants on the microhardness of root canal dentin in the presence and absence of surface-modifying agents. MethodsForty-eight root halves were prepared by longitudinal splitting of the distal roots of 24 freshly extracted mandibular human third molars and embedded in autopolymerizing acrylic resin, leaving the dentin surface exposed. After polishing, the microhardness values of the untreated dentin surfaces were recorded by using Vickers tester at the mid-root level. The root halves were randomly assigned to 6 groups composed of 8 samples each and treated for 5 minutes with one of the following irrigants: 17% EDTA, REDTA, 2% chlorhexidine gluconate (CHX), 2% CHX with surface modifiers (CHX-Plus), 6% NaOCl, or 6% NaOCl with surface modifiers (Chlor-XTRA). After surface treatment, dentin microhardness values were recorded at close proximity to the initial indentation areas. Experimental data were statistically analyzed by using the t test and one-way analysis of variance, followed by Tukey honestly significant difference test at α = 0.05. ResultsEDTA, REDTA, NaOCl, and Chlor-XTRA significantly decreased the microhardness of root dentin compared with intact controls (P < .05). ConclusionsThe addition of surface modifiers to the irrigants did not affect the microhardness of the samples.

Comparative Evaluation of the Effect of EDTA, EDTAC, NaOCl and MTAD on Microhardness of Human Dentin - An In-vitro Study.

The aim of this study was to evaluate the microhardness of human dentin by using four irrigating solutions. Materials and Methodos: A total of 40 extracted mandibular premolars were selected and sectioned horizontally in the middle third of the root. Forty specimens of 4 mm thickness were embedded in acrylic resin and polished. Four test groups, each group containing ten specimens were immersed in respective irrigating solution and subjected to vicker's microhardness test at T0, T2 and T5min. The data obtained were analyzed using the one way ANOVA followed by Tukey HSD method with ap=0.05 as the level for statistical significance. Suggested that there was no statistically significant difference in mean values between four experimental irrigating solutions. Mixture of Tetracycline isomer i.e. Doxycycline, Citric acid and a Detergent (Tween 80) MTAD not altered the microhardness of root canal dentin significantly and seems to be an appropriate irrigating solution, because of its harmless effect on the microhardness of the root canal dentin.

Effect of calcium hydroxide pastes and vehicles on root canal dentin microhardness

Background: Calcium hydroxide pastes used in the endodontic therapy may produce changes in the physical properties of the dentin. Objective: The purpose of this study was to evaluate the effect of calcium hydroxide pastes and their vehicles on microhardness of root canal dentin. Materials and Methods: Sixty maxillary anterior teeth were used. The crowns of the teeth were removed at the cemento-enamel junction. Canals were instrumented, horizontally sectioned into 2 segments, embedded in acrylic resin, and polished. A total of 120 specimens were randomly divided into 12 groups. Specimens stayed in contact with the vehicles or the pastes prepared with the calcium hydroxide powder and the same vehicles. The vehicles are: Distilled water, chlorhexidine, carticaine in the anesthetic solution, propylene glycol, monochlorophenol and monochlorophenol - propylene glycol. The references Vickers microhardness were obtained prior the application of the medicaments. Samples were then exposed to the medicaments for 3, 7, and 14 days, and microhardness measured again. The results were statistically analyzed by one-way ANOVA, Tukey test, and regression. Results: All vehicles and pastes, except distilled water, significantly decreased the microhardness of the root dentin; however, calcium hydroxide + camphorated monochlorophenol - propylene glycol and camphorated monochlorophenol - propylene glycol showed the highest decrease. Conclusion: Vehicles contribute to calcium hydroxide reduction of root canal dentin microhardness as constituent of endodontic pastes.

Effect of sodium hypochlorite under several formulations on root canal dentin microhardness

The aim of the present study was to evaluate the effect of three different formulations of sodium hypochlorite on the microhardness of root canal dentin in cervical and apical segments. Twenty-four extracted human teeth had their roots sectioned along their long axes in a buccolingual direction. One half of each root was selected, and transversely sectioned resulting in two segments, cervical and apical, with similar lengths. The specimens were divided into three groups (n=16), according to the sodium hypochlorite formulation used: (a) group 1, 2.5% sodium hypochlorite; (b) group 2, Chlor-XTRA; and (c) group 3, 5.5% sodium hypochlorite gel. These groups were subdivided in two subgroups (n=8): cervical and apical root segments. Before testing the substances, dentin microhardness was measured on each section, 100μm from the root canal with a Knoop tester. After 15min of application, a new measurement was performed on each segment. Data were collected and registered for statistical treatment. In both segments, the substances reduced dentin microhardness. No differences were observed between the groups, independent of the analyzed segment (P>0.05). All substances reduced dentin microhardness. Chlor-XTRA and 5.5% sodium hypochlorite gel promoted a reduction similar to the 2.5% sodium hypochlorite solution.

Comparative evaluation of Morinda citrifolia with chlorhexidine as antimicrobial endodontic irrigants and their effect on micro-hardness of root canal dentin: An in vitro study

Objectives: The current study was intended to compare and to evaluate in vitro the antimicrobial efficacy of Morinda citrifolia juice (MCJ) with chlorhexidine (CHX) as endodontic irrigants and their effect on micro-hardness of root canal dentin. Methodology: The study was divided into two parts. Part I for antibacterial testing consisted of preparing 60 dentin blocks of 4 mm height. All the dentin blocks were infected with Enterococcus fecalis for a period of 21 days. The experimental groups were Group I: 0.2% CHX; Group II: 6% MCJ; Group III: 6% MCJ + 0.2% CHX; Group IV: Saline. After 28 days of medication with the irrigants, the dentin shavings from root canal dentin was harvested and colony forming units counted. Part II for micro-hardness testing consisted of preparing 32 root halves and mounting them on blocks of acrylic resin. 8 samples per group were randomly divided into the experimental groups. The samples were then medicated with the irrigants for a period of 15 min and micro-hardness values were recorded. Results: Data obtained was analyzed using one-way ANOVA, Kruskal-Wallis and Mann-Whitney U-test and Student's paired t-test. Part I: Group I showed highest antibacterial activity followed by Group III with Group II taking the third place and were statistically significant (P < 0.001). Part II: None of the groups showed any effect on micro-hardness of root canal dentin, which was not statistically significant (P > 0.4). Conclusion: Nearly 0.2% of CHX showed the highest antimicrobial activity even after 28 days and 6% of MCJ also showed antibacterial activity, but to a lesser degree than CHX. None of the irrigants tested had any effect on the micro-hardness of root canal dentin.

The effect of Morinda Citrifolia juice as an endodontic irrigant on smear layer and microhardness of root canal dentin

PurposeThe purpose of this study was to evaluate the effect of Morinda Citrifolia Juice (MCJ) on smear layer removal and microhardness value of root canal dentin in compared with various endodontic irrigants. Material and methodsEighty-four single-rooted human teeth were prepared to apical size of #35. Since decoronation, samples were divided into seven groups of 12 in each (n=12). Specimens were finally irrigated by either 1: 2.5% NaOCl, 2: 6% MCJ, followed by a final flush of 17% ethylene diaminetetraacetic acid (EDTA), 3: 6% MCJ, 4: 2.5% NaOCl then17% EDTA, 5: MTAD, 6: 2% chlorhexidine (CHX), and 7: saline. After irrigation, all samples were subjected to Vickers microhardness test at 100 and 500-μm depths and then were examined under scanning electron microscopy (SEM) and ImageJ program was used to calculate open dentinal tubules. One way ANOVA and post hoc Tukey tests were used to reveal any significant differences among and between groups respectively. ResultsThe microhardness values at 100μm and 500μm for MTAD were significantly lower than for NaOCl+EDTA and MCJ+EDTA groups (p<0.05). MCJ+EDTA, NaOCl+EDTA, and MTAD protocol significantly removed smear layer in compared with control group (p<0.05), with no significant differences among these three groups. ConclusionsIt was concluded that 6% MCJ followed by a final flush of 17% EDTA can be regarded as an effective solution on smear layer removal without any adverse influence on microhardness property of root canal dentin.

The Effects of Two Root Canal Irrigants and Different Instruments on Dentin Microhardness ( In Vitro Study)

Aims: To measure the microhardness of root canal dentin using two types of irrigating solutions( 0.2% Chlorhexidine and 5.25% Sodium Hypochlorite) with and with out use of different types of root canal files (Stainless Steel-K files, Nickel-Titanium K-files or rotary Nickel-Titanium files). Materials & methods: The teeth divided in to four groups according to the type of irrigating solutions that used during root canal instrumentation with the use of normal saline as a control group, then each group sub divided in groups according to the instrument used in the root canal preparation, then after irrigation and preparation the roots sliced and root dentin microhardness measured using Vicker,s microhardness machine. Results: The result of this study showed that the type of instrument and Chlorhexidine have no effect on the microhardness of root canal dentin while Sodium Hypochlorite significantly decrease the microhardness of root canal dentin especially when use with Stainless Steel K-files and Nickel-Titanium K-files than when used with rotary Nickel-Titanium files. Conclusion: The microhardness of root canal dentin not affected by the type of root canal instruments.,The use of 5.25% Sodium Hypoch-lorite as a root canal irrigation significantly reduce the microhardness of root dentin within 3 mi-nutes., The use of Sodium Hypochlorite as a root canal irrigant with stainless steel K-files or Nickel-Titanium K-files reduce the microhardness of root canal dentin to greater extend than when use with rotary Nickel-Titanium files because the working time required with Stainless Steel K-files or Nickel-Titanium K-files was on the average three times longer than the working time with rotary Nickel-Titanium files. The use of sodium hypochlorite as a root canal irrigant with stainless steel K-files or Nickel-Titanium K-files reduce the microhardness of root canal dentin

A study of the relation between erosion and microhardness of root canal dentin

The aim of this study was to find a relation between erosion and microhardness of root canal dentin after irrigation with different canal irrigants. Seventy-two single-canal human premolar teeth were selected and enlarged by rotary Protaper files. The middle part of each root was transversely sectioned to a 4-mm slice. The initial microhardness values of intact specimens were measured at depths of 100 microm and 500 microm from the pulp-dentin interface using a Vickers microhardness tester. the specimens were divided into 6 groups of 12 specimens and were treated as follows: 1: 2.6% NaOCl, 2: 17% EDTA (5 minutes) then 2.6% NaOCl (5 minutes), 3: 17% EDTA (1 minute) then 2.6% NaOCl (1 minute), 4: MTAD (5 minutes), 5: 2% Chlorhexidine (5 minutes), and 6: saline (control), respectively. Posttreatment microhardness values were obtained in the same manner as the initial ones. Afterwards, the specimens were prepared for scanning electron microscopy analysis. The amount of dentin erosion was examined. Group 2 showed the most erosive effect on dentin (P < .0001) along with the least decrease of dentin microhardness at depth of 100 microm, whereas MTAD showed the most reduction of dentin microhardness and less erosive effect on dentin. It can be concluded that erosion is not the main factor in decreasing the dentin microhardness, whereas the amount of irrigant penetration might be the main cause.

Determination of calcium loss and its effect on microhardness of root canal dentin following treatment with 17% ethylenediaminetetraacetic acid solution at different time intervals - An in vitro study

Objectives: The aim of this study was to determine the Calcium loss and its effect on Microhardness of the root canal dentin following treatment with aqueous solution of 17% Ethylenediaminetetraacetic acid at different time intervals. Study Design: Twenty extracted human canine teeth were bisected longitudinally and root halves were embedded individually in rings with polyester resin. Samples were randomly divided into 7 groups based on different time intervals. Each group was immersed in the test solutions for different time intervals, after which the same samples were subjected for the evaluation of amount of Ca2+ release into the solution by Atomic Absorption Spectrophotometer. Then the samples were evaluated for the microhardness testing. Results: The results were statistically analyzed (p<0.05) showing the time dependant effect of 17% EDTA in both calcium loss as well as microhardness reduction in comparison with saline (control group) Conclusion: Root canal irrigation with 17 % EDTA solution is time dependant, increased irrigation time leads to structural changes, as evidenced by reduction of dentin microhardness.

The effect of EDTA, EGTA, EDTAC, and tetracycline-HCl with and without subsequent NaOCl treatment on the microhardness of root canal dentin

The purpose of this study was to evaluate the effect of single and combined use of ethylenediamine tetra acetic acid (EDTA), ethylene glycol bis [b-aminoethylether] N,N,N',N'-tetraacetic acid (EGTA), EDTA plus Cetavlon (EDTAC), tetracycline-HCl, and NaOCl on the microhardness of root canal dentin. The crowns of 30 single-rooted human teeth were discarded at the cementoenamel junction and the roots were bisected longitudinally to obtain root halves (N = 60). The specimens were embedded in autopolymerizing acrylic resin, leaving the root canal dentin exposed. Dentin surfaces were prepared for microhardness test by grinding and polishing. The reference microhardness values of untreated specimens were recorded using a Vicker's microhardness tester at the apical, midroot, and cervical levels of the root canal. Thereafter, the specimens treated with single (test solution only) or combined (test solution, followed by 2.5% NaOCl) versions of the irrigants for 5 minutes. Posttreatment microhardness values were obtained as with initial ones. Statistical comparisons between the test groups and among single and combined treatments were carried out using 2-way ANOVA with repeated measures (P =.05). Comparisons within each group with respect to application regions were made with Friedman's nonparametric 2-way analysis of variance at the same level of significance. All treatment regimens except distilled water significantly decreased the microhardness of the root canal dentin (P < . 05). The single and combined use of EDTA decreased the microhardness of the root canal dentin significantly more than all other treatment regimens (P < .05). Compared with their single-treatment versions, all combined treatment regimens decreased the mean microhardness values significantly (P < .05). A comparison of single and combined treatment regimens revealed significant decreases only for EDTA and EDTA + NaOCl in the coronal region and for EDTAC and EDTAC + NaOCl in the apical and middle regions of the root canal (P < .05). The use of EDTA alone or prior to NaOCl resulted in the maximum decrease in dentin microhardness. The softening effect of subsequent NaOCl treatment was both material and region dependent. However, for combined treatment regimens, subsequent use of NaOCl levels the statistical differences between the regional microhardness values obtained after treatment with EGTA, EDTAC, and tetracycline-HCl.

Effects of chlorhexidine and sodium hypochlorite on the microhardness of root canal dentin

The purpose of this study was to evaluate the effects of endodontic irrigants on the microhardness of root canal dentin. Thirty extracted single-rooted human teeth were used. The crowns were sectioned at the cementoenamel junction. Each root was transversely sectioned into cervical, middle, and apical segments, resulting in 90 specimens. The 3 sections of each root were separately mounted in an individual silicon device with acrylic resin. The specimens were randomly divided into the following 3 groups (n = 30), according to the irrigant solution used: (1) group 1, control (saline solution); (2) group 2, 2% chlorhexidine gluconate solution; and (3) group 3, 1% sodium hypochlorite (NaOCl). After 15 minutes of irrigation, dentin microhardness was measured on each section at 500 microm and 1000 microm from the pulp-dentin interface with a Vickers diamond microhardness tester in Vickers hardness number (VHN). Data obtained were analyzed using analysis of variance and the Tukey test (5%). Specimens irrigated with 2% chlorhexidine (group 2) or 1% NaOCl (group 3) presented lower values of dentin microhardness, with significant difference in relation to the control group (P < .05). It could be concluded that chlorhexidine and NaOCl solutions significantly reduced the microhardness of root canal dentin at 500 microm and 1000 microm from the pulp-dentin interface.

Evaluation of the Effect of Endodontic Irrigation Solutions on the Microhardness and the Roughness of Root Canal Dentin

The purpose of this study was to evaluate the effect of 0.2% chlorhexidine gluconate on the microhardness and roughness of root canal dentin compared with widely used irrigation solutions. Ninety, mandibular, anterior teeth extracted for periodontal reasons were used. The crowns of the teeth were removed at the CEJ. The roots were separated longitudinally into two segments, embedded in acrylic resin, and polished. A total of 180 specimens were divided into 6 groups of 30 teeth at random according to the irrigation solution used: group 1: 5.25% NaOCl for 15 min; group 2: 2.5% NaOCl for 15 min; group 3: 3% H2O2 for 15 min; group 4: 17% EDTA for 15 min; group 5: 0.2% chlorhexidine gluconate for 15 min; and group 6: distilled water (control). Each group was then divided into 2 subgroups of 15 specimens: groups 1a, 2a, 3a, 4a, 5a, and 6a were submitted to Vickers microhardness indentation tests; groups 1b, 2b, 3b, 4b, 5b, and 6b were used for determination of the roughness of root dentin. The data were recorded as Vickers numbers and Ra, microm for roughness test. The results were analyzed statistically by using one-way ANOVA and Tukey tests. The results indicated that all the irrigation solutions except chlorhexidine significantly decreased microhardness of root canal dentin (p < 0.05); 3% H2O2 and 0.2% chlorhexidine gluconate had no effect on roughness of the root canal dentin (p > 0.05). Although there are many other factors for irrigation solution preference, according to the results of this study, 0.2% chlorhexidine gluconate seems to be an appropriate endodontic irrigation solutions because of its harmless effect on the microhardness and roughness of root canal dentin.