Original Research In vitro evaluation of root canal preparation with plastic endodontic rotary finishing file - A SEM study ASHUTOSH * ASEEM P. TIKKU ** ANIL CHANDRA ** PROMILA VERMA *** RAKESH K. YADAV **** ABSTRACT Aim: To comparatively evaluate the efficacy of plastic endodontic rotary finishing file (F- file) with rotary, Stainless Steel K-file and, regarding smear layer removal. Materials and Methods: Thirty healthy maxillary premolars with two separate buccal and palatal canals were selected. Both buccal and palatal canals of each group (n=10) were instrumented by rotary, Stainless Steel K-file and respectively and irrigated with 17% EDTA and 5% Sodium Hypochlorite. Then palatal canal of each specimen was finished with F-file for smear layer removal. Then each specimen was visualized using scanning electron microscopy. Buccal and palatal canals of each specimen were compared for smear layer removal. Results: The statistical analysis was done using wilcoxon score and found no significant difference in smear layer score after using plastic file(p>0.005). Conclusions: It appears that finishing with plastic file (F-file) did not help in reducing smear layer and obtaining a better finished root canal. Keywords: Endodontics, F-file, smear layer, scanning electron microscopy Introduction Three dimensional cleaning and shaping of root canal is a key step in root canal treatment. Studies have shown that mechanical instrumentation of root canals leaves a smear layer covering the dentinal walls. A smear layer forms on the root canal wall as a byproduct generated by instruments used during cleaning and shaping. Need for removal of smear layer: a) Smear layer contains bacteria and protect the bacteria within dentinal tubules. b) Hinders the penetration of intracanal disinfectant. c) Compromise the seal of root canal filling. Recently, a new plastic rotary finishing file has been developed called the F-file. This pre sterilized, single use, plastic rotary file has a unique design with a diamond abrasive embedded into a nontoxic polymer. This file was designed to remove dentinal wall debris and agitate the sodium hypochlorite without further enlarging the canal. This study was carried out to comparatively evaluate the efficacy of plastic endodontic rotary * Senior Resident, ** Professor, *** Associate Professor, **** Assistant Professor, Department of Conservative Dentistry And Endodontics, Faculty of Dental Sciences, Chhatrapati Shahuji Maharaj Medical University, Lucknow. India. 30
ASHUTOSH, ASEEM P. TIKKU, ANIL CHANDRA, PROMILA VERMA, RAKESH K. YADAV finishing file (F- file) with rotary, Stainless Steel K-file and, regarding smear layer removal. Materials and Method Thirty extracted maxillary premolar teeth with straight root and two canals were selected.the crown of each tooth was removed at the level of the cemento-enamel junction(cej).two longitudinal grooves were prepared on the palatal and buccal surfaces of each tooth with a diamonddisk in a slow speed straight handpiece to facilitate vertical splitting with a chisel after canal instrumentation. The teeth were randomly divided into 3 groups, each group containing 10 teeth (n=10). Samples of all 3 groups were instrumented with 3 different sets of instruments. Group 1 (n=10), buccal and palatal canals of each tooth were instrumented with (Dentsply Maillefer, Switzerland) rotary Ni-Ti instruments. Similarly Group 2 (n=10) and Group 3 (n=10) were instrumented by Stainless steel K- file (Dentsply Maillefer,Switzerland) and (FKG Dentaire,La-Chaux-de Fondes, Switzerland) respectively. After the instumentation only the palatal canals of all samples were finished with plastic rotary finishing file (f-file) (Plastic Endo, ILC, Buffalo Grove,IL 60089). Size 10 K file was used for working length determination. Patency and glide path verification was done with size 15 K-file manually. Small amount of wax was placed at the apex to prevent irrigating solution to flow out. All the canals in all three groups were lubricated with RC Prep (17% EDTA) and irrigated with 5% sodium hypochlorite during instrumentation. The smear layer removal of 3 groups was observed at coronal, middle and apical thirds both after instrumentation by, SS file and files (buccal canals-subgroup 1a, 2a and 3a) and with plastic finishing file after instrumentation by, SS file and files (palatal canalssubgroup 1b,2b and 3b). After the complete instrumentation and irrigation, each canal was dried with absorbent paper points. Roots were sectioned and split vertically into two halves and subjected to SEM processing and examination. The samples were dried and coated with gold and examined using a scanning electron microscope. Representative sections of the coronal, middle, and apical thirds of the canal were used for evaluation at a magnification of 750X.After the central beam had been directed to the centre of the object by the SEM operator at 10X magnification, the magnification was increased to 750X and the canal wall region appearing on the screen was photographed. The cleaning ability of the Finishing file (Ffile) was evaluated using the debris and smear layer score system introduced by Hulsmann et al. These scoring systems were applied to the coronal, middle, and apical thirds of both canals of each sample. The scoring criteria for smear layer removal were as following: Score of the smear layer (Hulsmann et al.) Score 1: No smear layer, dentinal tubules open. Score 2: Small amount of smear layer, some dentinal tubules open. Score 3: Homogeneous smear layer 31
IN VITRO EVALUATION OF ROOT CANAL PREPARATION WITH PLASTIC ENDODONTIC ROTARY FINISHING FILE - A SEM STUDY covering the root canal wall, only few dentinal tubules open. SEM Photographs Score 4: Complete root canal wall covered by homogenous smear layer, no open dentinal tubules. Score 5: Heavy, non-homogenous smear layer covering the complete root canal wall. Scores of each group was recorded and statistical analysis was done. PHOTO 1(a) PHOTO 1(b) 1(a)SEM picture of middle third of root canal prepared by (smear score-1) 1(b)SEM picture of middle third of root canal prepared by and finished by f-file (smear score-1) Investigation Design PHOTO 2(a) PHOTO 2(b) 2(a)SEM picture of middle third of root canal prepared by Stainless Steel K-file (smear score-1) 2(b)SEM picture of middle third of root canal prepared by Stainless Steel K-file and finished by f-file (smear score-1) PHOTO 3(a) PHOTO 3(b) 3(a)SEM picture of middle third of root canal prepared by (smear score-1) 3(b)SEM picture of middle third of root canal prepared by and finished by f-file (smear score-1) Results For all the instruments maximum smear layer removal was at coronal level and least at apical third of the canal. But, no significant difference was observed in mean scores with or without use of plastic files at any level. Discussion From the observations of this study, it was found that among three instrumentation groups (, Stainless-Steel K-file and ), Stainless Steel K-file had highest smear scores while files had minimum at all the three levels i.e. coronal, middle and apical third. However, difference seen among three groups at any level was not statistically significant. 32
ASHUTOSH, ASEEM P. TIKKU, ANIL CHANDRA, PROMILA VERMA, RAKESH K. YADAV Table 1: Comparison of Mean Smear Scores in the three different groups After instrumentation with different file systems (Buccal canal) (n=10) After instrumentation with different file systems & finishing with PFF (palatal canal) (n=10) Significance of change SN Group Mean SD Mean SD Z p Coronal 0.70 0.271 0.853 0 1 20 0.42 30 0.503 0.739 47 0.57 50 0.110 0.912 Middle 50 0.71 0.981 0.393 00 0.82 23 013 0.353 60 0.872 1 77 57 0.86 695 0.090 Apical 1 0.74 0.965 0.393 40 17 20 14 0.571 1 06 0.668 0.579 07 0.87 90 0.96 046 0.296 Wilcoxon signed rank test used In our study, superior cleanliness in the coronal parts of the root canal compared to middle and apical part was observed. This result is in collaboration with F. Plaque et al. (2005). In this study showed that among all the three instrumentation groups (1, 2 and 3), the apical third of the canal was less clean than the middle and coronal thirds regardless of the instrument used. This observation is supported with studies of Schafer & Vlassis (2004) who compared cleaning effectiveness and shaping ability of two rotary nickel-titanium instruments: versus and found that middle and coronal third of root canals were cleaner than apical third. Similarly Wu & Wesselink (1995) studied efficacy of three techniques in cleaning the apical portion of curved root canals and found that the apical third of the canals were less clean than the middle and coronal thirds. Studies of Schafer and Zapke (2000), Gamabirini & Laszkiewicz (2002) and Schafer & Schlingemann (2003) have also confirmed that apical third of the canal was less clean than middle and coronal third. Overall in our study when the cleaning ability of the three instruments used was evaluated regarding smear layer removal, we observed that instruments shows a good cleaning ability than or other Ni-Ti instruments, our results 33
IN VITRO EVALUATION OF ROOT CANAL PREPARATION WITH PLASTIC ENDODONTIC ROTARY FINISHING FILE - A SEM STUDY are in concurrence with the study of E. Schafer & M. Vlassis (2004) who comparatively investigated and and found that the use of instruments resulted in significantly less remaining debris compared to canal shaping with instruments (p<0.001). Similarly F. Plaque et al. (2005) studied and cleaning ability in terms of smear layer scores and found 33% scores (Hulsmann) 1 & 2 for and 51% for. In Table 1, smear scores of buccal canal were compared with palatal canal (finished) at coronal, middle and apical third level and found no significant differences in smear scores. In all the three instruments used, no reduction in smear scores were seen following treatment with plastic file. Conclusion In our study, we observed that finishing with plastic files after instrumentation with, SS- K file and do not help in reducing the presence of smear layer and obtaining a better finished root canal. Its expenses and working time needs to be justified. References: Metzger Zvi, Cohen Raphela, Zary Raviv. The Self-adjusting file (SAF) Part-3 : Removal of debris and smear layer-a scanning electron microscope study. Journal of Endodontics 2010; 36(4): 697-70 McComb D, Smith DC.A preliminary scanning electron microscopic study of root canals after endodontic procedures. J Endod 1975;1:238-4 Mader CL,Baumgartner JC,Peters DD.Scanning electron microscopic investigation of the smeared layer on root canal walls. J Endod 1984;10:477-8 Torabinejad M, Handisides R,Khademi AA,Bakland LK.Clinical implications of the smear layer in endodontics:a review.oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;94:658-66. 5. Orstavik D, Haapasalo M, Disinfection by endodontic irrigants and dressings of experimentally infected dentinal tubules.endod Dent Traumatol 1990;6:142-49. 6. White RR,Goldman M,Lin PS.The influence of the smeared layer upon dentinal tubule penetration by plastic filling materials.j Endod 1984;10:558-6 7. Economides N, Liolios E,Kolokuris I, Beltes P.Long term evaluation of the influence of smear layer removal on the sealing ability of different sealers. J Endod 1999;25:123-25. 8. Shahravan Arash and Shadifar Fahimeh. Effect of smear layer on sealing ability of canal obturation : A systematic review and meta-analysis. Journal of Endodontics 2007; 33(2): 96-105. 9. Bahcall James and Olsen F. Kris. Clinical introduction of a plastic rotary endodontic finishing file. Endodontic Practice May 2007; 17-19. 10. Chopra Sonia, Murray Peter E. and Namerow Kenneth N. A scanning electron microscopic evaluation of the effectiveness of the F-file versus ultrasonic activation of a K- file to remove smear layer. Journal of Endodontics 2008; 34(10): 1243-45. 1 Plaque F, Musch U. and Hulsmann M. Comparison of root canal preparation using and rotary Ni-Ti instruments. International Endodontic Journal 2005; 38: 8-16. 1 Gambairini G,Laszkiewicz J.A scanning electron microscopic study of debris and smear layer remaining following use of GT rotary instruments.int Endod J.2002;35:422-7. 1 Peters OA, Barbakow F. rotary root canal preparation: effects of canal anatomy on final shape analysed by microcomputer tomography. International Endodontic Journal 2003; 36: 86-9 1 Schafer E & Vlassis M. Comparative investigation of two rotary Nickel-Titanium instruments: versus. Part Shaping ability in simulated curved canals. International Endodontic Journal 2004; 37: 229-238. 15. Wu MK, Wessellink PR. Efficacy of three techniques in cleaning the apical portion of curved root canals. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1995; 79:492-6. 16. Schafer E. Lau Robert. Comparision of cutting efficiency and instrumentation of curved canals with Nickel-Titanium and Stainless Steel instruments. Journal of Endodontics 1999; 25(6): 427-30. 34