Effectiveness of ethylenediaminetetraacetic acid (EDTA) and MTAD on debris and smear layer removal using a self-adjusting file

Effectiveness of continuous chelation irrigation protocol in endodontics: a scoping review of laboratory studies

This scoping review aimed to synthesize and explore the current boundaries and limitations of laboratory research on the effectiveness of continuous chelation irrigation protocol in endodontics. This scoping review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Extension for Scoping Reviews. Literature search was conducted on Pubmed and Scopus to identify all laboratory studies evaluating smear layer and hard-tissue debris removal or, antimicrobial efficacy, or dentine erosion induced by continuous chelation. Two independent reviewers performed the all review steps and the relevant items were recorded. Seventy-seven potentially relevant studies were identified. Finally, 23 laboratory studies met the eligibility criteria for qualitative synthesis. Seven studies focused on the smear layer/debris removal outcome, 10 on antimicrobial activity, and 10 on dentine erosion. In general, the continuous chelation protocol was equally or more effective in the cleanliness of root canals and antimicrobial activity compared with traditional sequential protocol. In addition, etidronate solutions seemed to be milder chelating agents compared to those with EDTA, thus resulting in reduced or no dentine erosion and roughness modification. Yet, the methodological differences among the included studies limit the results' generalizability. The continuous chelation seems to be equally or more effective in all investigated outcomes when compared with the traditional sequential protocol. The methodological variability among the studies and shortcomings in the methods employed limit the generalizability and clinical relevance of the results. Standardized laboratory conditions combined with reliable three-dimensional investigation approaches are necessary to obtain clinically informative findings.

The effects of sequential and continuous chelation on dentin

OBJECTIVE

Proteolytic and demineralizing agents have a profound influence on the dentin ultrastructure, which plays a key role in the mechanical integrity of the tooth and integrity of dentin-biomaterial interfaces. In-depth characterization of dentin treated with a novel root canal irrigation protocol comprising sodium hypochlorite (NaOCl) and etidronate (HEDP) is lacking. This study comprehensively characterized and compared the effects of the continuous chelation (NaOCl/HEDP) and sequential chelation (NaOCl/EDTA) protocols on dentin.

METHODS

Dentin blocks, dentin powder and root canals of mandibular premolars were distributed into Group 1, Saline (control); Group 2, NaOCl/EDTA; and Group 3, NaOCl/HEDP. Ultrastructural characteristics of the treated dentin were investigated using electron microscopy and light microscopy, while the surface roughness was analyzed using atomic force microscopy. Chemical compositional changes were characterized using Fourier transform infrared spectroscopy (FTIR) and energy-dispersive-X-ray spectroscopy (EDS), while collagen degradation was determined using ninhydrin assay. Data were statistically analyzed using multiple-factor one-way ANOVA and Tukey HSD tests (P = 0.05).

RESULTS

NaOCl/HEDP resulted in partially degraded, yet mineralized collagen fibers, with minimal alteration to the subsurface matrix. Conversely, NaOCl/EDTA dissolved the hydroxyapaptite encapsulation, exposing collagen fibre bundles. There was no significant difference in the surface roughness between the two protocols (P > 0.05). NaOCl/HEDP resulted in homogenous distribution of organic and inorganic components on the treated surface.

SIGNIFICANCE

This study highlighted that continuous chelation (NaOCl/HEDP) resulted in a frail surface collagen layer while sequential chelation (NaOCl/EDTA) exposed bare collagen fibres. These surface and sub-surface effects potentially contribute to structural failures of dentin and/or dentin-biomaterial interfacial failures.

Effect of Intermediate Flush Using Different Devices to Prevent Chemical Smear Layer Formation

This study compared the effect of intermediate flush with distilled water delivered by conventional irrigation, EndoVac microcannula or Self-Adjusting File (SAF) system in the prevention of chemical smear layer (CSL) formation. Thirty human premolars were used. Canals were prepared with Reciproc system and 5.25% NaOCl. After chemomechanical preparation, samples were divided in 3 groups (n=10) according to the intermediate irrigation protocol with distilled water using: conventional irrigation, EndoVac microcannula or SAF. A final flush with 2% chlorhexidine solution was used and scanning electron microscopy was performed to assess protocol effectiveness. Two calibrated evaluators attributed scores according the presence or absence of CSL on the surface of the root canal walls at the coronal, middle and apical thirds, as follows: (1) no CSL; (2) small amounts of CSL; (3) moderate CSL; and (4) heavy CSL. Differences between protocols were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between each root canal third. SAF resulted in less formation of CSL when compared with the conventional irrigation and EndoVac microcannula (p<0.05). When root canal thirds were analyzed, conventional irrigation and EndoVac groups showed less CSL formation at coronal and middle thirds in comparison to the apical third (p<0.05). In SAF group, there was no difference among the thirds (p>0.05). It may be concluded that an intermediate flush of distilled water, delivered by the SAF system resulted in a better reduction of CSL formation during chemomechanical preparation.

Comparative evaluation of smear layer removal by chitosan and ethylenediaminetetraacetic acid when used as irrigant and its effect on root dentine: An in vitro atomic force microscopic and energy-dispersive X-ray analysis

Aim

This study was undertaken to evaluate the efficacy of smear layer removal and nanostructural and chemical changes caused by chitosan and ethylenediaminetetraacetic acid (EDTA) on tooth surface using atomic force microscopic analysis and energy-dispersive X-ray (EDX) analysis.

Methodology

Forty single-rooted premolars were decoronated to a standard length of 15 mm and enlarged to Protaper F3 with irrigation of 1 mL 1% NaOCl and deionized water. Specimens were then divided into 4 groups with 10 samples each and subjected to final rinse with 17% EDTA solution, 0.2% and 0.5% chitosan solution for 1 min. Samples were sectioned into 2 halves. One half of sample from each group were subjected to EDX analysis to check the calcium/phosphate (Ca/P) ratio. The second half of sample from each group subjected to atomic force microscopy (AFM) analysis to study the smear layer removal and nanostructural changes. Statistical analysis was done using ANOVA and Chi-square test.

Results

The AFM images showed no difference in the elimination of smear layer. The quantitative analysis using AFM showed EDTA group had significantly higher surface alteration than chitosan. EDX analysis showed that the Ca/P ratio of root dentine in EDTA group is significantly lower than chitosan group.

Conclusion

Chitosan is an effective chelating agent with less alteration in radicular dentine.

The shaping and cleaning abilities of self-adjusting files in the preparation of canals with isthmuses after glidepath enlargement with ISO or ProTaper Universal NiTi files

Background/purpose

This study compared the shaping and cleaning ability of self-adjusting files (SAF) after glidepath enlargement with ISO NiTi files (Group I) or ProTaper Universal (PTU; Group II) for preparing maxillary premolar canals with isthmuses.

Materials and methods

Twenty-eight teeth containing isthmuses were scanned preoperationally after glidepath enlargement and preparation with SAF (n = 14). Changes in canal and isthmus volume, prepared surface, debris volume, and transportation were determined. Data were compared by t test between groups and paired t test within each group.

Results

No difference was observed regarding changes in canal volume or prepared surface between the two groups (P > 0.05). Paired t tests showed that the coronal and middle prepared areas of the canal after using SAF in Group I were statistically larger than those using ISO files, whereas the use of an adjuvant preparation with SAF after PTU resulted in a significant increase in the apical prepared area in Group II. ISO and SAF systems deviated less from the center than did PTU and SAF systems at most sections. After the use of SAF, isthmus volumes were significantly increased within each group (P < 0.05). Although less debris resulted from the use of SAF instruments as compared to glidepath instruments, there was no significant difference between both groups (P > 0.05).

Conclusion

SAF following glidepath enlargement with ISO files could improve preparation of the coronal and middle part of the canals, and adjuvant preparation with SAF after using large-taper instruments increased the apical prepared area.

The self-adjusting file (SAF) system: An evidence-based update

Current rotary file systems are effective tools. Nevertheless, they have two main shortcomings: They are unable to effectively clean and shape oval canals and depend too much on the irrigant to do the cleaning, which is an unrealistic illusionThey may jeopardize the long-term survival of the tooth via unnecessary, excessive removal of sound dentin and creation of micro-cracks in the remaining root dentin. The new Self-adjusting File (SAF) technology uses a hollow, compressible NiTi file, with no central metal core, through which a continuous flow of irrigant is provided throughout the procedure. The SAF technology allows for effective cleaning of all root canals including oval canals, thus allowing for the effective disinfection and obturation of all canal morphologies. This technology uses a new concept of cleaning and shaping in which a uniform layer of dentin is removed from around the entire perimeter of the root canal, thus avoiding unnecessary excessive removal of sound dentin. Furthermore, the mode of action used by this file system does not apply the machining of all root canals to a circular bore, as do all other rotary file systems, and does not cause micro-cracks in the remaining root dentin. The new SAF technology allows for a new concept in cleaning and shaping root canals: Minimally Invasive 3D Endodontics.

Efficacy of Two Irrigants Used with Self-Adjusting File System on Smear Layer: A Scanning Electron Microscopy Study

Mechanical instrumentation of root canals produces a smear layer that adversely affects the root canal seal. The aim of this study was to evaluate efficacy of MTAD and citric acid solutions used with self-adjusting file (SAF) system on smear layer. Twenty-three single-rooted human teeth were used for the study. Canals were instrumented manually up to a number 20 K file size. SAF was used to prepare the root canals. The following groups were studied: Group 1: MTAD + 5.25% NaOCl, Group 2: 20% citric acid + 5.25% NaOCl, and Group 3: Control (5.25% NaOCl). All roots were split longitudinally and subjected to scanning electron microscopy. The presence of smear layer in the coronal, middle, and apical thirds was evaluated using a five-score evaluation system. Kruskal-Wallis and Mann-Whitney U tests were used for statistical analysis. In the coronal third, Group 2 exhibited the best results and was statistically different froms the other groups (P < 0.05). There was not a significant difference among the three thirds of groups according to in-group comparisons (P > 0.05). The solutions used in Group 1 and 2 could effectively remove smear layer in most of the specimens. However, citric acid was more effective than MTAD in the three thirds of the canal.

Efficacy of three irrigation agitation techniques on bacterial elimination: a microbiologic and microscopic evaluation

The aim of this study was to compare in vitro reduction of Enterococcus faecalis by using three agitation methods. Fifty-five mandibular premolar teeth were used. The root canals were prepared by using ProTaper instruments to size F4. Fresh bacterial suspensions were inoculated into each canal and the teeth were incubated at 37°C under aerobic conditions for 3 weeks. The specimens in negative control group were not contaminated and the teeth in positive control receive no further instrumentation or irrigation after contamination. The contaminated teeth were divided into three experimental groups and two control groups. The experimental groups were as follows according to agitation of NaOCl irrigation solution; group 1, the brush-covered NaviTip FX needle; group 2, EndoVac apical negative pressure irrigation system; and group 3, self-adjusting file (SAF). Following the final irrigation, samples obtained with sterile #40 H-file from teeth and the file used were placed into sterile microcentrifuge tubes. After the incubation period, bacterial colony numbers were noted as CFU/ml. Three teeths were randomly selected from each group for scanning electron microscope evaluation. The three groups were compared with the Kruskal-Wallis test. Comparisons between three groups were made with the Mann-Whitney U-test with Bonferroni correction. SAF was significantly effective in elimination of E. faecalis when compared to EndoVac (p < 0.05). There was no difference between NaviTip FX needle and other two methods (p > 0.05). In conclusion, agitation of NaOCl with SAF for 2 min may be an effective alternative approach.

Ethylenediaminetetraacetic acid in endodontics

Ethylenediaminetetraacetic acid (EDTA) is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a polyamino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. It is produced as several salts, notably disodium EDTA and calcium disodium EDTA. EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. A review of the literature and a discussion of the different indications and considerations for its usage are presented.