Comparative analysis of root surface smear layer removal by different etching modalities or erbium:yttrium-aluminum-garnet laser irradiation. A scanning electron microscopy study

The purpose of this study was to evaluate the effect of erbium:yttrium-aluminum-garnet (Er:YAG) laser (2.94 mu m) irradiation on the removal of root surface smear layer of extracted human teeth and to compare its efficacy with that of citric acid, ethylenediamine tetra-acetic acid (EDTA), or a gel containing a mixture of tetracycline hydrochloride (HCl) and citric acid, using scanning electron microscopy (SEM). Thirty human dentin specimens were randomly divided into six groups: G1 (control group), irrigated with 10 ml of physiologic saline solution; G2, conditioned with 24% citric acid gel; G3, conditioned with 24% EDTA gel; G4, conditioned with a 50% citric acid and tetracycline gel; G5, irradiated with Er:YAG laser (47 mJ/10 Hz/5.8 J/cm(2)/pulse); G6, irradiated with Er:YAG laser (83 mJ/10 Hz/10.3 J/cm(2)/pulse). Electron micrographs were obtained and analyzed according to a rating system. Statistical analysis was conducted with Kruskal-Wallis and Mann-Whitney tests (P < 0.05). G1 was statistically different from all the other groups; no statistically significant differences were observed between the Er:YAG laser groups and those undergoing the other treatment modalities. When the two Er:YAG laser groups were compared, the fluency of G6 was statistically more effective in smear layer removal than the one used in G5 (Mann-Whitney test, P < 0.01). Root surfaces irradiated by Er:YAG laser had more irregular contours than those treated by chemical agents. It can be concluded that all treatment modalities were effective in smear layer removal. The results of our study suggest that the Er:YAG laser can be safely used to condition diseased root surfaces effectively. Furthermore, the effect of Er:YAG laser irradiation on root surfaces should be evaluated in vivo so that its potential to enhance the healing of periodontal tissues can be assessed.

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.

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

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Smear layer removal capacity of disinfectant solutions used with and without EDTA for the irrigation of canals: a SEM study.

The purpose of this study was to carry out a scanning electron microscopic (SEM) analysis of the cleaning qualities and smear layer removal from root canal walls, instrumented and irrigated with 2.5% NaOCl, 2.0% chlorhexidine and saline solutions. Fifty extracted teeth were used in this study. All teeth were radiographed to determine the existence of a single canal. The crowns were cut at the cervical limit and the root canals were instrumented with K-type files up to size 45. During root canal preparation, irrigations were made with the different solutions being evaluated: Group 1: 2.5% NaOCl (10 roots); Group 2: 2.5% NaOCl and 17% EDTA for 2 minute (10 roots); Group 3: 2.0% chlorhexidine (10 roots); Group 4: 2.0% chlorhexidine and 17% EDTA for 2 minutes (10 roots); Group 5: saline solution (5 roots); Group 6: saline solution and 17% EDTA for 2 minutes (5 roots). After instrumentation, the canals were irrigated with each one of the solutions and the roots were cut in the buccolingual direction for SEM analysis, at the cervical, middle and apical thirds, to ascertain the presence or absence of smear layer and debris. SEM analysis was performed by three calibrated examiners and scores were submitted to Kruskal-Wallis test at the significance level of p = 5%. Results showed that the use of 17% EDTA decreased the smear layer significantly (p < 0.05) for all evaluated solutions in all thirds. When EDTA was not used, a significantly higher quantity of smear layer on the apical third was observed only in the NaOCl groups. The use of 17% EDTA was significant for debris removal except for the chlorhexidine groups. The following conclusion could be drawn: the use of 17% EDTA was necessary to enhance cleanness of the root canals.

Efficacy of EDTA-T gel for smear layer removal at root surfaces

Objective: The purpose of this in vitro study was to investigate the efficacy of EDTA gel preparation, associated with texapon detergent (EDTA-T), for removing the smear layer at human root surfaces. Method and materials: An experimental smear layer was produced by scaling using periodontal curettes, and the root surfaces were etched with the following concentrations of EDTA-T: 5%, 10%, 15%, 20%, 24%, and negative control (saline solution) for 1, 2, or 3 minutes using both passive and active methods. The surfaces were evaluated by scanning electron microscopy, and photomicrographs were evaluated in relation to smear removal. Results: All EDTA-T groups were more effective than the control group (P < .0001). EDTA-T at 15% was more effective when applied by the passive method, although this difference was not observed for the active method. The active method was statistically better than the passive method (P < .0001). Conclusion: The etching of the root surface with EDTA-T gel by active application, independently of the other factors evaluated, was effective for smear layer removal.

Smear layer removal and collagen fiber exposure using tetracycline hydrochloride conditioning

Aim: Smear layer removal and collagen fiber exposure may improve periodontal treatment and regeneration. This in vitro study assessed smear layer removal and collagen fiber exposure after tetracycline hydrochloride (TTC) application on root surfaces using scanning electron microscopy (SEM). Methods and Materials: Root cementum was removed with diamond burs followed by scaling and root planning. Four hundred fifty samples were divided into ten groups: a control (saline application) and nine different TTC concentrations were applied at doses of 10, 25, 50, 75, 100, 125, 150, 200, and 250 mg/ml. The TTC application was performed in all groups in three different ways (passive, brushing, and burnishing) and at three different periods of conditioning (1, 2, and 3 minutes). A previously trained, calibrated, and blind examiner evaluated photomicrographs of the samples using Sampaio's index (2005). Statistical analysis was performed using the Kruskal-Wallis' and Dunn's tests. Results: The concentrations of 50 mg/mL and 75 mg/mL applied by burnishing were the most effective in smear layer removal and collagen fiber exposure. Both the passive mode of application (p=0.0001) and 1 minute period of application (p=0.002) were the least effective. Conclusions: The concentrations of 50 mg/mL and 75 mg/mL applied by burnishing during 2 or 3 minutes were the most effective. Clinical Significance: These parameters may be applied in periodontal procedures involving TTC root conditioning to optimize results.

Smear layer removal for collagen fiber exposure after citric acid conditionings

Aim: The aim of the present study was to compare the removal of the smear layer and exposure of collagen fibers of the root surface following the application of five citric acid solution concentrations. Methods and Materials: Two hundred seventy (270) samples were equally divided into six groups (n=45) for treatment with saline solution (control) and five different concentrations of citric acid (0.5, 1, 2, 15, and 25 percent). Three acid application methods were used (passive, brushing, and burnishing) as well as three application periods (1, 2, and 3 minutes). A previously trained, calibrated (kappa score = 0.93), and blind examiner subsequently scored scanning electron micrographs (SEMs) of the samples. Statistical analyses were performed by using Kruskal-Wallis and Dunn's post-hoc tests. Results: According to the results obtained and within the limitations of the methodology used, the citric acid applications were more effective than the control treatment of applying saline solution (p<0.05). However, no statistically significant differences were observed among the three application methods and three application periods. Descriptive analyses showed that best results for exposure of collagen fibers were obtained with the application of citric acid at 25 percent by brushing for 1 or 3 minutes. Conclusions: The best results for exposure of collagen fibers in this study were obtained with application of citric acid at 25 percent by brushing for 1 or 3 minutes, even though there were no statistically significant differences among the groups. Clinical Significance: The best results for exposure of collagen fibers on root surfaces noted in this study were obtained with application of citric acid at 25 percent by brushing for 1 or 3 minutes. © 2010 Seer Publishing LLC.

Influence of dental exposure to oral environment on smear layer removal and collagen exhibition after using different conditioning agents

Although in vitro studies have shown encouraging results for root surface conditioning with demineralizing agents, in vivo studies have failed to show its benefits in periodontal healing. This can be attributed to several factors, among which, the hypermineralization of dental surface. Therefore, this in vitro study compared, using scanning electron microscopy (SEM), the effect of root surface conditioning with different conditioners (1% and 25% citric acid, 24% EDTA and 50 mg/mL tetracycline hydrochloride) in impacted teeth and in teeth that had their roots exposed to the oral environment. One trained examiner assessed the SEM micrographs using a root surface modification index. There was a tendency of more root surface modification in the group of impacted teeth, suggesting that the degree of root mineralization influences its chemical demineralization.

Effect of the root canal final rinse protocols on the debris and smear layer removal and on the push-out strength of an epoxy-based sealer

The aim of the present study was to evaluate the efficacy of QMiX, SmearClear, and 17% EDTA for the debris and smear layer removal from the root canal and its effects on the push-out bond strength of an epoxy-based sealer by scanning electron microscopy (SEM). Forty extracted human canines (n=10) were assigned to the following final rinse protocols: G1-distilled water (control), G2-17% EDTA, G3-SmearClear, and G4-QMiX. The specimens were submitted to a SEM analysis to evaluate the presence of debris and smear layer, respectively, in the apical or cervical segments. In sequence, forty extracted human maxillary canines with the root canals instrumented were divided into four groups (n=10) similar to the SEM analysis study. After the filling with AH Plus, the roots were transversally sectioned to obtain dentinal slices. The specimens were submitted to a push-out bond strength test using an electromechanical testing machine. The statistical analysis for the SEM and push-out bond strength studies were performed using the Kruskal-Wallis and Dunn tests (α=5%). There was no difference among the G2, G3, and G4 efficacy in removing the debris and smear layer (P>0.05). The efficacy of these groups was superior to the control group. The push-out bond strength values of G2, G3, and G4 were superior to the control group. The ability to remove the debris and smear layer by SmearClear and QMiX was as effective as the 17% EDTA. The final rinse with these solutions promoted similar push-out bond strength values. © 2013 Wiley Periodicals, Inc.

Effectiveness of EDTA and EDTA-T brushing on the removal of root surface smear layer.

The purpose of this study was to compare the removal of root surface smear layer following active application of EDTA gel and EDTA-T (texapon) gel in different concentrations (5%, 10%, 15%, 20% and 24%), using scanning electron microscopy. A total of 220 dentin blocks obtained from the root surfaces of extracted teeth were divided into 3 groups: Group I - (control) application of saline solution (n = 20); Group II - EDTA gel (pH 7.0) was applied in the following concentrations: 5%, 10%, 15%, 20% and 24% (n = 100); Group III - EDTA-T gel (pH 7.0) applied in the same concentrations described above (n = 100). The photomicrographs were evaluated by one calibrated examiner using a smear layer removal index and following statistical analysis (Kruskal-Wallis test). The results demonstrated that the specimens treated with EDTA and EDTA-T gel presented a better smear layer removal than the control group (p < 0.01); no statistically significant differences were observed between the EDTA and EDTA-T groups and between the concentrations tested (Mann-Whitney, p > 0.05). Within the limits of this study, it can be concluded that all treatment modalities effectively removed the smear layer from the root surface. The addition of texapon into the EDTA gel formulation did not increase its effectiveness.

Evaluation of the Smear Layer and Hybrid Layer in Noncarious and Carious Dentin Prepared by Air Abrasion System and Diamond Tips

Purpose: To analyze the smear layer and the hybrid layer in noncarious and carious dentin prepared by different cutting instruments and restored with composite resin. Study design: Cavities were randomly prepared in 160 specimens (noncarious and artificial carious dentin) by high-speed diamond tips (KG Sorensen 1013), air abrasion system (Prepstart, Danville Engineering), ultrasonic tip (CVDentus 8.3231-1), and ultrasonic tip associated with ultrasonic cavitation by water for 10 s. Half of the cavities in each group were conditioned with 37% phosphoric acid for 15 s. The amount of smear layer and dentinal tubules present were analyzed using scanning electron microscopy and graded from 0 to 3. Cavities were prepared in another 20 noncarious specimens and 20 carious specimens and restored with adhesive composite resin system. The restorations were hemisected longitudinally and analyzed using scanning electron microscopy to evaluate the hybrid layer and resinous prolongation characteristics, using scores ranging from 1 to 6. Results: The data were statistically analyzed using Kruskal-Wallis and Dunn tests at 5% of significance level. There was evidence that the most efficient smear layer removal was the acid etching in the noncarious dentin and the water ultrasonic cavitation in the carious dentin. The hybrid layer formed on the noncarious and carious dentin prepared by the ultrasonic tip was more regular than in the specimens prepared by high-speed diamond tip, with many resinous prolongations. Conclusion: The ultrasonic tip seems to be a promising tool for carious dentin cavity preparation. Microsc. Res. Tech. 73:597-605, 2010. (C) 2009 Wiley-Liss, Inc.

Influence of natural fruit juices in removing the smear layer from root surfaces - An in vitro study

Certain elements of a patient's diet may be associated with dentin hypersensitivity. The intent of this study was to evaluate the degree of removal of the smear layer from dentin surfaces by various fruit juices. A smear layer was created on extracted human teeth by manual scaling. The roots were reduced and distributed into 8 experimental groups. Distilled water was the negative control. The juices were applied by 2 methods: topical application and topical application with friction. Specimens were photomicrographed and graded according to an index of smear layer removal. With topical application, all but 2 of the tested substances resulted in significantly greater removal of the smear layer and opening of dentinal tubules than was the case with the negative control (p = 0.05); the exceptions were Gala apple and Italian grape juices, which were no different from the control. For the active application (with friction), most substances removed more smear layer than the control (p < 0.05); Gala apple, Italian grape and orange juices were similar to the control. For each of the tested substances, removal of the smear layer did not differ with the method of application (topical vs. friction; p > 0.05). It is concluded that natural fruit juices can remove the smear layer from dentin surfaces, and the efficacy of this removal varies with the type of juice. © J Can Dent Assoc 2004.