Effects on smear layer and debris removal with varying volumes of 17% REDTA after rotary instrumentation

The purpose of this study was to quantify the volume of 17% ethylene diamine tetra-acetic acid (EDTA) needed to efficiently remove the smear layer after rotary instrumentation, and to determine if additional irrigation has any effect on debris removal. Forty single canal teeth were instrumented with ProFile GT rotary instruments. Experimental groups were irrigated with 1, 3, or 10 ml of 17% EDTA for 1 min, followed by a final rinse with 3 ml of 5.25% sodium hypochlorite (NaOCl). Samples were scored for debris remaining and examined under SEM to determine quality of smear layer removal. There were no significant differences among groups when comparing either debris remaining or quality of smear layer removal. EDTA irrigation volume greater than 1 ml did not improve debris removal. Efficient removal of the smear layer was accomplished with a final rinse of 1 ml of 17% EDTA for 1 min, followed by 3 ml of 5.25% NaOCl.     

pH changes after manual or ultrasonic instrumentation and smear layer removal with EDTA or ultrasonic

Abstract – The purpose of the present study was to evaluate the influence of instrumentation techniques associated with the smear layer removal, in the pH changes of the root surface. Thirty mandibular humans premolars were divided into three groups: Group I – instrumentation by Ohio technique and final cleaning with EDTA (3 minutes); Group II – instrumentation by Ohio technique and final cleaning with ultrasonic (1 minute); Group III – instrumentation by the ultrasonic technique and final cleaning with ultrasonic (1 minute). The pH was measured in the cavities prepared in the cervical, middle and apical thirds of the lateral wall of each root. The teeth were evaluated at the initiation of the experiment, and 3, 7, 14, 21, 30 days after of the intracanal dressing of the calcium hydroxide with camphorated p‐monochlorophenol (Calen/PMCC). All the groups presented increasing pH values; group III presented the highest average pH, followed by groups II and I; the values for the apical third were lower than those of the middle and cervical thirds (anova and Tukey test). The results showed that the biomechanical preparation by the ultrasonic technique and smear layer removal with ultrasonic showing the highest diffusion of the calcium and hydroxyl ions from the intracanal dressing (P < 0.05).     

Effect of shortened irrigation times with 17% ethylene diamine tetra-acetic acid on smear layer removal after rotary canal instrumentation

The purpose of this study was to evaluate whether irrigation times of 1 minute or less with 1 mL of 17% ethylene diamine tetra-acetic acid (EDTA) effectively removed the smear layer from root canals after rotary instrumentation. Forty single-canal teeth were decoronated, instrumented, and divided into 3 experimental groups (n = 10). Ten teeth served as positive and negative controls. The experimental groups received a final rinse with 1 mL of 17% EDTA for 1 minute, 30 seconds, or 15 seconds followed by a final 3-mL rinse with 6% NaOCl. Teeth were split longitudinally and prepared for scanning electron microscopy imaging. Digital images (350x) of the approximate center of the coronal, middle, and apical sections were graded for quality of smear layer removal by 3 endodontists. Data were analyzed with nonparametric tests, with significance level set at alpha = .05. Significantly greater smear layer removal was found in the 1-minute EDTA irrigation group than the 30-second or 15-second groups.     

Evaluation of the smear layer removal effectiveness of EDTA using two techniques: an SEM study

Obtaining the cleanest canal possible before obturation is one of the goals of endodontic treatment. The purpose of this study was to compare the smear layer removal capability of ethylenediamine tetra-acetic acid (EDTA) application with passive ultrasonic and cotton wrapped on reamer activation. Twelve extracted human teeth with single root canals were used for the study. They were conventionally hand instrumented using reamers and K files. The apical aspect of the canals was enlarged to a #40 file. The teeth were divided into 4 four groups, instrumented and irrigated as follows: Group-A EDTA agitated at the end of preparation with cotton wrapped on a reamer for 1 min; Group-B EDTA applied with ultrasonic agitation for 1 min; Group-C irrigated with EDTA+sodium hypochlorite (NaOCl) (negative control group); and Group-D irrigated with distilled water (positive control group). After scanning electron microscopic study at three different levels, smear layer and dentinal tubules were scored. Means were tested for significance using the Z test. When the techniques were compared, the cotton wrapped on reamer agitation method was as successful as the ultrasonic activation of the files. Although all groups had significantly higher smear layer scores at apical compared to coronal sections, no significant differences were recorded.     

A comparative SEM study of smear layer removal by detergents and EDTA on the root surface

The present study performed an SEM evaluation of the efficiency of the following detergents on smear layer removal on the root surface: sodium lauryl sulphate, Plax, castor oil, and EDTA 24%. Sodium lauryl sulphate did not remove the smear layer and showed the worst results of all detergents tested. Plax and castor-oil detergents showed similar results represented by partial removal of the smear layer; these results were better than those obtained in the control (physiologic serum) and sodium lauryl sulphate groups. Neutral EDTA 24% was the most efficient detergent for smear layer removal.     

Effect of 17% EDTA and MTAD on intracanal smear layer removal: A scanning electron microscopic study

The purpose of this study was to determine the effectiveness of MTAD as the final irrigant to remove the smear layer, compared with that of 17% EDTA, both following root canal irrigation with 5.25% sodium hypochlorite (NaOCl). Fifty‐five extracted maxillary and mandibular single‐rooted human teeth were prepared by a crown‐down technique using rotary 0.04 and 0.06 taper nickel‐titanium files. 5.25% sodium hypochlorite was used as the intracanal irrigant. The canals were then treated with 5 mL of one of the following solutions as final rinse: 5.25% sodium hypochlorite, 17% EDTA or MTAD. The presence or absence of smear layer in the coronal, middle and apical portion of each canal was examined with a scanning electron microscope. The results showed that MTAD is an effective final rinse solution for removing the smear layer in canals irrigated with sodium hypochlorite. When 17% EDTA was used as a final rinse, the smear layer was removed from the middle and coronal thirds of canal preparations, but it was less effective in the apical third of the canals.     

The effect of application time of EDTA and NaOCl on intracanal smear layer removal: an SEM analysis

AIM: To verify, under the scanning electron microscope (SEM), the influence of irrigation time with ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl) on intracanal smear layer removal. METHODOLOGY: Twenty-one extracted human permanent teeth with single straight root canals were included. The root canals of the teeth were instrumented and, at the end of preparation, were irrigated with 3 mL of 15% EDTA, followed by 3 mL of 1% NaOCl for 1 min (group 1), for 3 min (group 2), and for 5 min (group 3). The canals of teeth in group 4 (control) did not receive the final irrigation. The teeth were sectioned longitudinally and prepared for an SEM. The dentinal wall of cervical, middle and apical thirds was graded according to the amount of debris and smear layer remaining on the walls. The results were analysed using the Kruskal-Wallis and Conover-Inman tests. RESULTS: In all the canals of experimental groups irrigation with EDTA and NaOCl completely removed the smear layer from the cervical and middle thirds. In the apical third, the dentine surface were partially covered, particularly in the teeth of group 1, where there was significantly more smear layer when compared with the other thirds in the same group (P<0.007). However, the Kruskal-Wallis test showed overall that there were no significant differences between groups 1, 2 and 3 (P>0.05). CONCLUSION: In this limited laboratory study, canal irrigation with EDTA and NaOCl for 1, 3 and 5 min were equally effective in removing the smear layer from the canal walls of straight roots.     

Evaluation of ethylenediaminetetraacetic acid (EDTA) solution and gel for smear layer removal

The purpose of this in vitro study was to compare the efficacy of 24% ethylenediaminetetraacetic acid (EDTA) gel and 17% EDTA solution in cleaning dentine walls after root canal instrumentation. Thirty human canine teeth were divided into three groups of 10 teeth each. In Group 1, 1% sodium hypochlorite was used as the irrigating solution; in Group 2, 1% sodium hypochlorite was used with 17% EDTA solution; and in Group 3, 1% sodium hypochlorite was used with 24% EDTA gel. The presence of a smear layer was analysed after instrumentation using scanning electron microscopy. The Kruskal-Wallis test revealed a statistical difference (P < 0.05) between Groups 1 and 2, and also between Groups 1 and 3. No difference was observed between Groups 2 and 3 (P > 0.05). The results indicate that 1% sodium hypochlorite alone does not remove the smear layer and that there was no statistical difference between EDTA gel and EDTA solution in smear layer removal.     

A scanning electron microscopy study of root surface smear layer removal after topical application of EDTA plus a detergent

The aim of the present study was to compare root surface smear layer removal following topical application of EDTA and EDTA-T (Texapon). Extracted human teeth had their cementum removed and were mechanically scaled. A total of 220 root specimens were obtained and were randomly assigned to the following groups: I-saline solution (control), II-EDTA; III-EDTA-T. Groups II and III specimens were assigned to different EDTA gel concentrations: 5%, 10%, 15%, 20% and 24%. Smear layer removal score was assessed for each specimen by scanning electron microscopy. The results demonstrated that EDTA and EDTA-T gel led to a higher root surface smear layer removal when compared to the control group. The 5% EDTA gel also showed a higher smear layer removal than the 15%, 20% and 24% EDTA gels (p<0.05). No difference could be found between the different concentrations of EDTA-T gels tested (p>0.05). EDTA gels had statistically significantly lower smear layer scores than the EDTA-T gels for the 5% and 10% concentrations. The results suggested that topical application of EDTA or EDTA-T gel led to significant smear layer removal of the mechanically treated root surfaces. The addition of a detergent to the EDTA gel formula did not improve smear layer removal of the root surface.     

Reduction of intracanal bacteria using GT rotary instrumentation, 5.25% NaOCl, EDTA, and Ca(OH)2

This study was conducted to determine the bacterial reduction using Profile GT files and a strict irrigation protocol utilizing 5.25% NaOCl and EDTA. The additive antibacterial effect of Ca(OH)2 was also evaluated. In addition, the study compared the bacterial reduction with the GT protocol versus larger instrumentation. Thirty-one subjects with apical periodontitis were recruited. Bacterial samples were taken upon access (S1), after instrumentation and a strict irrigation protocol (S2), and following >1 wk of Ca(OH)2 (SC). A log10 transformation of colony forming units was done since sample bacterial counts are not normally distributed. At S1, 93.55% of canals sampled bacteria. At S2, 52.72% of the cases sampled bacteria. At SC, 14% of the cases cultured bacteria. The McNemar test showed a significant reduction (p<0.0009) in bacteria between S1 and S2. This was also true between S2 and SC (p<0.0019). It was concluded the GT protocol significantly reduced the number of bacteria in the canal but failed to render the canal bacteria free in more than half of the cases Ca(OH)2 application significantly further reduced bacteria. Lastly, large apical instrumentation removed more bacteria than small apical instrumentation.     

The effect of different irrigation protocols on smear layer removal in root canals of primary teeth: a SEM study

Objective: The purpose of this study was to compare the efficacy of different irrigation protocols on smear layer removal in root canals of primary teeth by scanning electron microscopy (SEM).

Material and methods: The study was conducted with 40 extracted maxillary primary incisor teeth divided into four groups (n?=?10) as 1% sodium hypochlorite (NaOCl), 10% ethylenediaminetetraacetic acid (EDTA)+1% NaOCl, 6% citric acid (CA)+1% NaOCl, and 0.9% physiological saline (PS). After the irrigation procedures, root canal walls were examined by SEM and the efficacies of irrigation solutions in smear layer removal were scored and compared. Data were analyzed using Kruskal–Wallis, Friedman and Siegel Castellan tests.

Results: The smear layer removal was found to be statistically more effective in groups of 10% EDTA + 1% NaOCl and 6% CA + 1% NaOCl when compared with the other groups (p?<?.05). Smear removal efficacy was statistically significantly higher in coronal and medium thirds when compared with the apical regions in the experimental groups.

Conclusions: It was concluded that 10% EDTA + 1% NaOCl and 6% CA + 1% NaOCl could be alternative irrigation protocols regarding smear layer removal. However, due to the absence of erosive dentinal changes, it might be suggested that using 6% CA + 1% NaOCl can be recommended compared to 10% EDTA + 1% NaOCl in primary root canals.     

Comparison of hand stainless steel and nickel titanium rotary instrumentation: a clinical study

The aim of this study was to compare the effect of hand instruments and rotary nickel titanium Flex-Master files used by eight experienced dentists in private practice on the extent of straightening of curved root canals. In patients, 110 canals were prepared by FlexMaster instruments, and 84 canals were enlarged using hand instruments. After instrumentation, all canals were obturated. Preoperative and postoperative radiographs were taken of each tooth using customized bite blocks. Straightening of the canal curvatures was determined with a computer image analysis program. Preparation time and size of the master apical file were also recorded. The use of FlexMaster instruments resulted in significantly less straightening and a shorter preparation time (p < 0.0001) compared with hand instrumentation. Master apical file sizes were significantly greater for FlexMaster than for hand instruments (p < 0.01). This clinical study indicates that FlexMaster instruments prepared curved canals rapidly and with only minimal straightening.     

The effect on coronal leakage of liquid adhesive application over root fillings after smear layer removal with EDTA or Er:YAG laser

OBJECTIVE: To evaluate coronal microleakage in filled root canals that received different biomechanical preparations and application of liquid adhesives over the root filling and the pulp chamber walls. STUDY DESIGN: Root canals of 94 extracted canine teeth were filled after being biomechanically prepared with 1% sodium hypochlorite and divided into 3 groups. In 2 groups attempts were made to remove the smear layer with either 17% EDTA or Er:YAG laser irradiation (10 Hz, 250 mJ input, 112 mJ output). Liquid adhesive (Super Bonder and Single Bond adhesive) was applied and the teeth were immersed for 90 days in India ink. RESULTS: Statistically significant differences were found for the different preparations, the use of liquid adhesives, and the different liquid adhesives. The use of Er:YAG laser, EDTA, and the liquid adhesive reduced coronal microleakage (P < .01). CONCLUSIONS: Because of the risk of coronal microleakage, endodontically treated teeth should be restored as quickly as possible.     

Effectiveness of different activated irrigation techniques on debris and smear layer removal from curved root canals: a SEM evaluation

This study evaluates the effectiveness of different activated irrigation techniques on removal of debris and smear layer from curved root canals. Ninety mandibular molars with a root canal curvature between 20 and 40 degrees were assigned to 4 groups (n = 20): syringe irrigation (SI), passive ultrasonic activation (PUI), sonic activation with EDDY (ED) or EndoActivator (EA) and a control group. Mesiobuccal root canals were prepared to size 40, 0.04 and irrigated with NaOCl (3%) according to the respective technique. Roots were split longitudinally and subjected to scanning electron microscopic analysis. Presence of debris and smear layer was evaluated using 5‐grade scoring systems with 200× and 1000× magnification, respectively. Data were analysed with nonparametric analysis for ordinal longitudinal data (α = 5%). Activation of the irrigant significantly improved smear layer removal (P < 0.05). Regarding debris, only activation with EA and ED was significantly more effective than SI (P < 0.05). No activation technique was able to eliminate debris and smear layer completely from curved root canals.     

机用镍钛锉根管预备的临床应用研究

目的：比较机用镍钛锉与手用K型锉根管预备的临床应用。方法：将牙位相同、诊断相同，全身情况类似的患者按随机配对原则分入甲乙两组，甲组为镍钛锉预备组；乙组为K型锉预备组，每组50例患者。结果：对于单根管牙齿，使用机用镍钛锉进行根管预备，所用时间与传统手用K型锉根管预备相比无显著差异，对于双根管牙及磨牙而言，采用机用镍钛进行根管预备所用时间明显少于使用传统手用K型锉根管预备，根管预备一周内，使用机用镍钛锉根管预备与传统手用K型锉根管预备术后反应无显著差异，结论：传统手用K型锉预备根管相比，机用镍锉具有省时省力的优点。