|Year : 2015 | Volume
| Issue : 5 | Page : 520-523
|Effectiveness of different formulations of Endo-PTC to promote root canal cleaning
Evaldo Rodrigues1, Sílvio Albergaria2, Gabriela LR Barbosa3, Mariana Santoro4, Paulo Pacheco4, Emmanuel João Nogueira Leal Silva4
1 Department of Health, School of Dentistry, Feira de Santana State University (UEFS), Feira de Santana, Brazil
2 Bahia Federal University (UFBA), Campinas State University (UNICAMP), Campinas - SP, Brazil
3 Department of Oral Radiology, Campinas State University (UNICAMP), Campinas - SP, Brazil
4 Department of Endodontics, Grande Rio University (UNIGRANRIO), Duque de Caxias - RJ, Brazil
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|Date of Submission||18-Jul-2015|
|Date of Decision||14-Aug-2015|
|Date of Acceptance||15-Sep-2015|
|Date of Web Publication||17-Dec-2015|
| Abstract|| |
Context: Endo-PTC are used during endodontic treatment; however, until now no study evaluated the cleaning of dentin walls after use of different Endo-PTC formulations.
Aims: The aim of this study was to assess qualitatively, by means of scanning electron microscopy (SEM) images, the cleaning of dentin walls of root canals after chemomechanical preparation (CMP) using Endo-PTC cream and Endo-PTC light associated to 2.5% sodium hypochlorite and 17% ethylenediamine tetraacetate (EDTA).
Materials and Methods: Forty single-rooted human maxillary central incisors with straight canals and fully formed apex were selected. The specimens were randomly divided into four groups depending on the type of Endo-PTC and the final rinse with 17% EDTA. After CMP, all specimens were sectioned and processed for observation of the apical thirds by using SEM. Three calibrated evaluators attributed scores to each specimen.
Statistical Analysis Used: The differences between irrigation protocols were analyzed with Kruskal-Wallis test followed by Bonferroni adjustment for multiple comparisons. The significance level was set at α = 0.05.
Results: The use of Endo-PTC cream or Endo-PTC light did not influence the smear-layer (SL) removal (P > 0.05). When EDTA were used, it was obtained the best cleaning results with no significant difference between the substances (P < 0.05).
Conclusions: It can be concluded that EDTA is essential to promote SL removal which was not affected by the type of Endo-PTC formulation.
Keywords: Endodontics, scanning electron microscopy, smear-layer
|How to cite this article:|
Rodrigues E, Albergaria S, Barbosa GL, Santoro M, Pacheco P, Leal Silva EJ. Effectiveness of different formulations of Endo-PTC to promote root canal cleaning. Indian J Dent Res 2015;26:520-3
Dentin debris are formed by the mechanical action of instruments (manual or mechanical) in association with organic tissue, microorganisms and auxiliary chemical substances during chemo mechanical preparation (CMP), forming the so-called smear-layer (SL).  SL is a nonhomogeneous structure weakly adhered to the root canal walls, having a thickness of about 1-2 μ and capable of penetrating the dentinal tubules to a depth of 40 μ (smear plugs).  This SL can alter the effectiveness of root canal dressings as well as the penetration of root canal sealers into dentinal tubules, thus influencing adaptation and sealing ability of filling materials and decreasing the bond strength of resin-based materials. ,, Considering the need to remove the SL formed during CMP, large numbers of chemical substances and various combinations have been tested to seek the best protocol to bring together all the necessary requirements. 
|How to cite this URL:|
Rodrigues E, Albergaria S, Barbosa GL, Santoro M, Pacheco P, Leal Silva EJ. Effectiveness of different formulations of Endo-PTC to promote root canal cleaning. Indian J Dent Res [serial online] 2015 [cited 2019 Dec 10];26:520-3. Available from: http://www.ijdr.in/text.asp?2015/26/5/520/172079
Among these substances, Endo-PTC cream is an irrigant which acts as a lubricant reducing friction between the instrument and the root canal wall. This cream is a mixture of urea peroxide (10%), Tween 80 detergent (15%) on a Carbowax basis (75%). When associated with sodium hypochlorite (NaOCl), it has an antimicrobial activity even in the presence of organic matter, due to the effective disinfectant action presented by urea peroxide. Moreover, when in contact with the hypochlorite, nascent oxygen, and active intermediate chlorine compounds are released in a characteristic effervescence of neutralization reaction, having a mechanical action, pushing the organic and inorganic debris to the pulp chamber that are sucked into the irrigation/aspiration process. Besides these properties, its use increases dentin permeability, improving the antimicrobial action in the root canal system.  More recently, the molecular weight of the vehicle (Carbovax) was changed, achieving a more fluid consistency, originating a new product known as Endo-PTC Light. However, until now, no study evaluated the ability of this new formulation to prevent SL formation. Therefore, the aim of this study was to assess qualitatively, by means of scanning electron microscopy (SEM) images, the cleaning of dentin walls of root canals after CMP using Endo-PTC cream and Endo-PTC light associated with 2.5% NaOCl and 17% ethylenediamine tetraacetate (EDTA). The null hypothesis tested was that: (1) There are no differences among Endo-PTC cream and Endo-PTC light regarding the cleaning of dentin walls, (2) there are no differences in the SL removal when using or not EDTA.
| Subjects and methods|| |
Selection and preparation of the specimens
Forty human single-rooted maxillary central incisors with straight single canals and mature apices, were selected for this study. They were stored at 4°C in 0.2% thymol solution.
The crowns were removed by using a diamond saw (Diamond Wafering Blade, Series 15 LC, Buehler, IL, USA) on an Isomet 1000 Machine (Buehler, IL, USA) under water cooling at 350 rpm to obtain root specimens with standardized length of 15 mm. All specimens had their apex sealed with utility wax (Technew, Rio de Janeiro, RJ, Brazil) to prevent the flow of irrigants through it. The working length was determined by a #15 file (Dentsply-Maillefer, Ballaigues, Switzerland) that was introduced into the canal until its tip was visualized at the apical foramen; and from this measure, 1 mm was reduced. Next, the specimens were randomly divided into four groups regarding irrigants used during CMP, as follow:
All specimens were instrumented using a crown-down technique and K-files. When the first instrument bind to the WL, the instrumentation was completed with the use of three files immediate above of this instruments. Endo-PTC cream or light filled root canals before each file insertion. A total volume of 20 mL 2.5% NaOCl was used per root canal during biomechanical preparation. After this step, Group II and IV was irrigated with 3 mL 17% EDTA (pH = 7.7) delivered at a 1-mL/min rate for 3 min.
- Group I: Root canal preparation with Endo-PTC cream associated with NaOCl 2.5%
- Group II: Root canal preparation with Endo-PTC cream associated with NaOCl 2.5% and final irrigation with 17% EDTA
- Group III: Root canal preparation as Endo-PTC light associated with NaOCl 2.5%
- Group IV: Root canal preparation with Endo-PTC light associated with NaOCl 2.5% and final irrigation with 17% EDTA.
Scanning electron microscopy
Specimens were dried with medium-sized paper points (Endopoints, Paraiba do Sul, RJ, Brazil) and two longitudinal grooves were prepared on both buccal and lingual surfaces by using a diamond disc without penetrating the canal. The roots were then split into two halves with a hammer and chisel. For each root, the half containing the most visible part of the apex was used for study. Each specimen was dehydrated in graded series of ethanol solutions, critically point dried, mounted on stubs, gold-sputtered, and then examined with a scanning electron microscope (Jeol, JSM 5600 LV, Noran Instruments, USA). Photomicrographs of the central region of the canal in the apical, middle and cervical thirds were obtained using ×1000 magnification and stored in TIF files, totaling 240 photomicrographs. The following scores were attributed - 0: No SL and dentinal tubules open; 1: Small amounts of scattered SL and dentinal tubules open; 2: Thin SL and dentinal tubules partially open; 3: Partially covered with thick SL; 4: Totally covered with thick SL.  After the determination of scores, all photomicrographs were analyzed by three-blinded examiners, expert in endodontics and well calibrated, which did not know the group or region of the image under analysis.
SEM images were assessed two times in random order by three-blinded observers at 1-week interval without knowing the previous result. Weighted coefficient kappa (Kw) was used to measure the interobserver reproducibility between observers separately for each time period and to measure the intraobserver reproducibility between the time periods separately for each observer. The differences between irrigation protocols were analyzed with Kruskal-Wallis test followed by Bonferroni adjustment for multiple comparisons. The significance level was set at α = 0.05.
| Results|| |
The kappa test showed good agreement among observers, with values of 0.9 or above. Representative images for each group are shown in [Figure 1]. The mean scores for SL removal regarding each irrigating protocol were listed in [Table 1]. The use of ENDO-PTC cream or ENDO-PTC light did not influenced the SL removal (P > 0.05). When EDTA were used, it was obtained the best cleaning results with no significant difference between the substances (P < 0.05).
|Figure 1: Scanning electron microscopy micrographs representative of different groups in each specimen third (×1000)|
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|Table 1: Means±SD for smear layer removal in each tested groups at each root canal third |
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| Discussion|| |
Although there was controversy in the literature regarding the removal of SL, today there is a consensus about the importance of removing it. The literature has characterized the SL as a pathogenic cocktail that contains remnants of pulp tissue as well as microorganisms and their by-products that compromise the success of endodontic therapy. The SL also alters the effectiveness of intracanal medicaments, the penetration of endodontic sealers into dentinal tubules, and both adaptation and sealing capacity of the filling materials. ,,, The first results of this study showed no differences regarding SL removal when using Endo-PTC cream or Endo-PTC light. Therefore, the null hypothesis was plainly accepted. Yamazaki et al. also showed the ability of Endo-PTC cream associated to EDTA in the SL removal;  however, to the best of the authors knowledge, this is the first attempt to evaluate SL removal by using Endo-PTC light. A previous study demonstrated the ability of Endo-PTC associated to substances with chelating action to remove SL.  Both substances have a creamy or gel-like consistency and aid in lubricating the root walls thereby diminishing friction among instruments and root canal walls and also suspending debris resulted from CMP.
The results of this study also demonstrated that when EDTA was not used, the SL removal was significantly lower when compared to groups where it was used, independent of the presentation of Endo-PTC. Therefore, the second null hypothesis was rejected. The efficacy of EDTA-based protocols in removing the SL are in accordance with observations from other studies. ,, These results are explained because EDTA has effective SL ability.  These results also emphasize that the isolated use of Endo-PTC associated only to NaOCl does not have the ability to promote a good SL removal. Regarding the comparison of canal thirds, removal of SL was significantly better in the coronal and middle regions than in the apical third of the root canals, when EDTA was used. These results are in agreement with previous studies ,, and might be related to the ability of chemical substances to achieve the apical third.
SEM is commonly used for the identification of organic/inorganic debris and SL on the root canal walls after endodontic preparation, allowing to obtain detailed picture with higher magnification imagining of the dentinal tubules.  The methodological limitations found in conventional score-based SL removal SEM studies has been already exposed.  Total root canal area is considerable larger than the dentin area observed under microscopy. Moreover, the observation area is nonrandomized which is directly dependent to operator selection.  As the SEM images are evaluated by a scoring system, which is consistently subjective, another observer bias factor is invariably present. The descriptive score assessments rarely use different examiners with interexaminer reproducibility verification using unweighted Kappa statistics to validate the subjective findings.  Therefore, checking intraexaminer and interexaminer bias is an important necessity to control the result quality. In the present study, Kappa values showed excellent concordance between three observers in two separate time periods.
Under the conditions of this study, it can be concluded that all groups were associated with SL. Groups were EDTA was used was associated with significantly less SL compared with groups were this chelating was not used. Moreover, no differences were observed among Endo-PTC cream or Endo-PTC light. Future studies might consider different strategies to promote better SL removal, especially in the apical third.
Financial support and sponsorship
This study was partially funded by FAPERJ grants E-26/102.169/2013, E-26/201.491/2014 and E-26/111.690/2013.
Conflicts of interest
There are no conflicts of interest.
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Emmanuel João Nogueira Leal Silva
Department of Endodontics, Grande Rio University (UNIGRANRIO), Duque de Caxias - RJ
Source of Support: None, Conflict of Interest: None
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