“A COMPARATIVE EVALUATION OF SMEAR LAYER REMOVAL WITH THREE IRRIGATING SOLUTIONS: AN IN-VITRO SCANNING ELECTRON MICROSCOPIC STUDY”
BRIEF RESUME OF THE INTENDED WORK 6.1 NEED FOR THE STUDY:
Three dimensional cleaning and shaping of the root canal system are the main goals of root canal treatment. Complete debridement, with smear layer removal is an asset and could help to achieve a successful outcome of the root canal treatment.1
Mechanical instrumentation of the root canal produces smear layer that covers the dentinal tubules. The smear layer itself may be infected and may protect the bacteria within the dentinal tubules. It can hinder the penetration of intracanal medicaments and sealers into the dentinal tubules.2 The smear layer can also act as a barrier between obturating materials and the canal wall and thus interfere with the formation of an appropriate seal.3 Nontoxic calcium chelating solutions are advocated for smear layer removal. EDTA (Ethylenediamine tetraacetic acid) is probably the most frequently used chelator in endodontics.4 Etidronic acid (1-Hydroxyethylidene-1,1-bisphosphonate or HEBP) is a biocompatible chelator that can be used in combination with NaOCL without short-term loss of desired properties of either compounds.5 Maleic acid has been found to remove smear layer when used as an acid etchant in restorative dentistry.2 Thus assuming the importance of complete removal of smear layer in root canal treatment, this study will evaluate the efficacy of three endodontic irrigants in smear layer removal through scanning electron microscopic image analysis.
6.2 REVIEW OF LITERATURE: An in vitro study was conducted in the year 2005 to test an aqueous gel containing 1-Hydroxyethylidene-1,1-bisphosphonate (HEBP) regarding its interactions with sodium hypochlorite, its calcium binding capacity and its potential in preventing the formation of smear layer when used in conjunction with rotary root canal preparation. The study concluded that none of the experimental gel components (2% alginate, 3% aerosil, 10% tween 80 and 18% HEBP) showed short term interactions with hypochlorite, whilst EDTA, peroxide and glyde immediately reduced the hypochlorite in solution. Under the conditions of this study, HEBP gel appeared advantageous over currently available products.6 In the year 2008 an in vitro study was done to assess both longitudinal and quantitative efficacy of HEBP and EDTA in removing the smear layer. The study concluded that EDTA is a strong chelator that quickly removes smear layer but that might also affect underlying sound dentine structure. On the other hand HEBP is a weaker chelator that probably should be administered in conjunction with sodium hypochlorite during the whole instrumentation process.7 A comparative study of smear layer removal and erosion in apical intraradicular dentine with three irrigating solution, using SEM evaluation was done in the year 2009. SEM study showed that there is no significant difference among biopure MTAD, 17% EDTA, 42% citric acid or 5.25% NaOCL in removing the smear layer, but the efficacy of biopure MTAD and 17% EDTA in removing the smear layer was significantly greater than 5.2% NaOCL .8 In the year 2009, a study was done to evaluate the effects of EDTA, etidronic acid and peracetic acid irrigation on human root dentine and smear layer. The results show that the decalcifying agents were all able to remove or prevent a smear layer but they eroded the dentine wall differently, out of which etidronic acid and NaOCl showed dentine wall erosion to a lesser extent. The study also concluded that irrigating protocols employing either etidronic or peracetic acid showed potential to replace the conventional treatment with EDTA.5 In the year 2009, a study was done to compare the efficacy of maleic acid and EDTA in smear layer removal from instrumented human root canals. This in vitro study was evaluated by SEM analysis. The result of the study showed that at the coronal and middle thirds there was no significant difference between EDTA and maleic acid and both were equally efficient in removal of smear layer. But in the apical third maleic acid showed significantly better smear layer removal ability than EDTA.2
An in vitro study was done in the year 2010 to evaluate the influence of final rinse techniques on ability of 17% EDTA on removing the smear layer. The study concluded that the continuous rinse with 5 ml of EDTA for 3 minutes effectively removes the smear layer from root canals.1
6.3 OBJECTIVES OF THE STUDY
To compare and evaluate the efficacy of 17% EDTA, 18% etidronic acid and 7% maleic acid in removal of the smear layer.
MATERIALS AND METHODS : 7.1 SOURCE OF DATA
30 extracted human single rooted mandibular premolar teeth with single canal will be collected.
7.2. METHOD Teeth will be randomly divided into three groups containing ten teeth in each group.
Group I-10 samples with 17%EDTA irrigation.
Group II-10 samples with 18% ETIDRONIC ACID irrigation.
Group III-10 samples with 7% MALEIC ACID irrigation.
The teeth will be decoronated to obtain working length of 17mm for all samples. Working length determination and instrumentation up to 40 size (K file) with 2.5% NaOCL irrigation between each file will be done followed by irrigation with 5ml of saline. Then each sample will be irrigated with 5ml of each irrigant for 1 minute.
Final irrigation will be done with 5ml of distilled water. Longitudinal sectioning of the samples will be done. Then the samples will be observed under scanning electron microscope at apical, middle and coronal levels.
The images will be scored according to the criteria given by Torabinejad et al:2
= No smear layer (no smear layer on the surface of the root canal: all tubules were clean and open).
= Moderate smear layer (no smear layer on the surface of the root canal, but tubules contained debris)
= Heavy smear layer (smear layer covered the root canal surface and the tubules).
STATISTICAL ANALYSIS :
Kruskal-Wallis analysis of variance followed by Mann-Whitney U-test for individual comparisons. The level for the significance will be set at 0.05.
7.3 Does the study require any investigations or interventions to be conducted on patients or other humans or animals? If so please describe briefly? No 7.4Has ethical clearance been obtained from your institution in case of 7.3? NOT APPLICABLE
LIST OF REFERENCES :
Mello I, Kammerer BA, Yoshimoto D, Macedo MCS, Joao HA.Influence of final rinse technique on ability of ethylenediaminetetraacetic acid of removing smear layer. J Endod 2010;36:512-514.
Ballal N V, Kandian S, Mala K, Bhat K S, Acharya S. Comparison of the efficacy of maleic acid and ethylenediaminetetraacetic acid in smear layer removal from instruemntated human root canal: A Scanning electron microscopic study .J Endod 2009;35:1573-1576.
Sharavan A, Haghdoost A, Adl A, Rashimi H, Shadifar F. Effect of smear layer on sealing ability of canal obturation: A systematic review and meta-analysis. J Endod 2007;33:96-105.
Zehnder M, Schicht O, Sener B, Schmidlim P. Reducing surface tension in endodontic chelator solutions has no effect on their ability to remove calcium from instrumented root canals. J Endod 2005;31:590-592.
Lottani s, Gautschi H, Sener B, Zehnder M. Effects of ethylenediami-etetraaceticacid, etidronic and peracetic acid irrigation on human root dentine and the smear layer. Int Endod J 2009;42:335-343.
Girard S, Paque F, Badertscher M, Sener B, Zehnder M. Assessment of a gel type chelating preparaton containing 1- hydroxyethylidene 1, bisphosphonate. Int Endod 2005;38:810-816.
De-Deus G, Zehender M, Dent DM, Reis C, Fidel S, Fidel RAS et al. Longitudinal co-site optical microscopy study on the chealating ability of etidronate and EDTA using a comparative single tooth model. J Endod 2008;34:71-75.
Mancini M, Armellin E, Casaglia A, Cerroni L, Cianconi L A. Comparative study of smear layer removal and erosion in apical intraradicular dentine with three irrigating solutions: A Scanning electron microscopy evaluvation. J Endod 2009;35:900-903.