Original Research Evaluation of the effect of chlorhexidine gluconate as an endodontic irrigant on the apical seal - An in vitro study ROOPASHREE M. S. KALA M. * INTRODUCTION One of the most important objectives in nonsurgical Endodontic therapy is to disinfect the entire root canal system before obturation of the canal-- 1. Endodontic therapy is primarily based on the removal of potentially noxious stimuli from the complex root canal system. This therapy is more difficult if the root canal is infected. Although a variety of instrumentation and irrigation techniques exist, it has been shown that debris is regularly left behind. These techniques aid in reducing the microbial flora of the infected canals and help to dissolve the necrotic tissue. Irrigants also serve to lubricate the file during instrumentation. Therefore several irrigating solutions have been recommended for use in the pulp space preparation 2. Sodium hypochlorite is used as an endodontic irrigant due to its necrotic tissue dissolving capacity and antimicrobial properties. The adverse effects of Sodium hypochlorite include tissue toxicity, pungent odor to the patient, and discoloration of teeth and corrosion of dental equipments. For these reasons another irrigant, which has the potential to counteract these adverse effects, are desirable and Chlorhexidine gluconate serves these purposes 4. Chlorhexidine has broad spectrum of antibacterial properties, Chlorhexidine has demonstrated substantivity. Irrigation with 2% Chlorhexidine has been shown to prevent microbial activity with residual effects for 48 hours. Chlorhexidine is an excellent root canal irrigant for patients who are allergic to Sodium hypochlorite 5. Along with a proper root canal preparation and disinfection, an effective apical sealing guarantees a long-term successful endodontic treatment. A sealer associated with gutta-percha is generally used to achieve an impervious apical sealing. The sealer serves as a lubricant when inserting the gutta-percha point, as a filling material to fill the irregularities of the preparation, and is necessary because gutta-percha does not bond spontaneously to the dentinal walls of the prepared canal. Adhesion of the sealers to both gutta-percha and to dentin may also improve the sealing properties of the endodontic sealers. The assessment of linear dye penetration apically or coronally has been the most common in vitro method of examining the adaptation of a root filling to the canal walls. This is based on the supposition that the depth of dye penetration will represent the gap between the root filling and the canal wall 12. The purpose of this study was to evaluate whether Chlorhexidine Gluconate (0.2%), when * Professor and Head, Dept. of Conservative Dentistry & Endodontics, Govt. dental college & research institute, Bangalore. 26
ROOPASHREE M. S., KALA M. used as an endodontic irrigant, would affect the seal obtained when using three different endodontic sealers. MATERIALS AND METHODS One hundred human maxillary anterior single rooted teeth extracted for periodontal reasons were used in this study, which were collected from the Department of Oral and Maxillofacial Surgery, Government Dental College and Research Institute, Bangalore. The procedure for preparation and obturation was standardized for all groups and performed by a single operator. The crowns of all hundred maxillary anterior teeth were severed at proximal Cemento-Enamel junction using a carborundum disc. The teeth were randomly divided into nine experimental groups of ten teeth each, a positive and negative control group of five teeth each. The working lengths were established by placing #10 file into the root canal until it was visible at the apical foramen, then 1mm was subtracted from that length. The root canals were instrumented in a step back manner using flexofiles and Gates Glidden drills up to the working length to a master apical file size of #40. The coronal and the middle portion were flared to a gradual taper using #3 and #4 Gates Glidden drills. Three milliliters of irrigant was used after every use of Gates Glidden drill or the endodontic file. Three different irrigating solutions were used during this experiment. Teeth in groups 1, 2, 3 were irrigated using sterile saline (0.9% sodium chloride), teeth in groups 4, 5, 6 were irrigated using 3% Sodium hypochlorite and teeth in group7, 8, and 9 were irrigated using 0.2% Chlorhexidine Gluconate solution. Both control groups were irrigated using sterile saline. The apical patency was checked again by passing a # 10 file through the apical foramen. After every instrumentation, the canals were thoroughly irrigated using respected irrigating solutions, later the root canals were dried with paper points and standardized Gutta-percha points that fit with tug back at the working length, were selected as master points. In groups 1, 4 and 7 Zinc oxide eugenol sealer was used, AH plus sealer was used in groups 2, 5, and 8, Metapex sealer was used in-group 3, 6 and 9. The positive control group was obturated with gutta-percha without sealer, and the negative control group was obturated using lateral condensation technique of gutta-percha and Zinc oxide eugenol sealer. The coronal access cavity was sealed with glass ionomer cement and final radiographs were taken in the bucco-lingual direction to check the density of the filling. After 2 days all the study specimens were thoroughly dried, the root surface except for the apical 2mm that was coated with two applications of nail varnish. The teeth were immersed in Methylene blue 2% for 2 days at 37 0 C. The teeth were rinsed under tap water for half an hour to remove dye on external root surface. The teeth were then sectioned vertically along the long axis. The samples were then observed under Stereomicroscope. The depth of dye leakage was measured with a millimeter scale. Statistical Analysis was done using One-way Analysis of Variance (ANOVA). RESULTS AND OBSERVATIONS 27
EVALUATION OF THE EFFECT OF CHLORHEXIDINE GLUCONATE AS AN ENDODONTIC IRRIGANT ON THE APICAL SEAL - AN IN VITRO STUDY LEAKAGE VALUES FOR ALL THE GROUPS TEETH Group-I Group-II Group-III Group-IV Group-V Group-VI Group-VII Group-VIII Group-IX +VE -VE (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) control control Group Group (mm) (mm) 1 1.52 0.34 2.85 2.31 0.00 1.56 2.03 0.52 1.65 2.97 0.34 2 2.68 0.87 2.58 1.22 0.00 3.00 1.31 0.00 1.54 1.34 1.45 3 1.39 2.92 0.94 1.11 0.00 2.00 0.29 0.00 0.24 3.43 0.98 4 0.00 0.00 1.56 0.01 0.87 1.48 0.00 0.00 0.00 5.67 2.12 5 0.76 2.74 0.00 0.00 3.76 0.76 0.00 0.00 0.56 3.66 1.04 6 0.00 0.00 0.00 0.23 1.78 1.11 0.00 1.46 1.44 7 0.00 0.98 2.16 0.00 0.00 0.00 0.00 0.29 0.00 8 0.00 0.00 3.60 2.10 2.48 0.00 1.03 1.13 1.56 9 3.76 1.75 0.00 0.00 0.00 0.00 0.08 0.00 2.54 10 2.44 0.00 0.90 0.00 0.31 0.00 0.98 0.00 0.00 This table shows the apical leakage in millimeters group I to group IX and positive and negative control groups in which the dye penetration scores obtained from calibrated value under stereomicroscope and the mean and standard deviation of the same. Comparison between Normal saline 0.9%, Sodium hypochlorite 3%, Chlorhexidine gluconate 0.2% groups in which Chlorhexidine gluconate groups showed minimal leakage compared to other groups with highest leakage in Normal saline group (Table 1). When compared each irrigant with the three types of sealers, showed Metapex whichever irrigant has been used with it, shows maximum leakage with minimal leakage in AH Plus sealer and moderate leakage with Zinc oxide eugenol sealer (Table 2 and Graph1). When 0.9% normal saline was compared with the all three types of sealers; ZnoE sealer, AH Plus and Metapex root canal sealer even though leakage occurred in all the groups 0.9% normal saline irrigant- Metapex root canal sealer showed maximum leakage where as 0.9% normal saline irrigant-ah Plus sealer showed minimal leakage with moderate leakage in 0.9% normal saline irrigant- Zinc oxide eugenol root canal sealer (Table 2 and Graph2). When 3% Sodium hypochlorite root canal irrigant was compared with all three types of root canal sealers; ZnoE root canal sealer, AH Plus root canal sealer and Metapex root canal sealer, even though leakage occurred in all the groups 3% Sodium hypochlorite - Metapex sealer showed maximum leakage where as 3% Sodium hypochlorite irrigant-ah Plus sealer showed minimal leakage with moderate leakage in 3% Sodium hypochlorite irrigant- Zinc oxide eugenol root canal sealer (Table 2 and Graph 3). 0.2% Chlorhexidine gluconate root canal irrigant was compared with the all three types of root canal sealers. Even though leakage occurred in all the groups, 0.2% Chlorhexidine gluconate - 28
ROOPASHREE M. S., KALA M. Metapex sealer groups showed maximum leakage, 0.2% Chlorhexidine gluconate -AH Plus sealer showed minimal leakage with moderate leakage in 0.2% Chlorhexidine gluconate - Zinc oxide eugenol sealer (Table 2 and Graph 4). The positive control group showed maximum leakage values where no sealer had been used than negative control group, which showed minimal leakage values (Table 2 and Graph 5). Samples Showing Microleakage 29
EVALUATION OF THE EFFECT OF CHLORHEXIDINE GLUCONATE AS AN ENDODONTIC IRRIGANT ON THE APICAL SEAL - AN IN VITRO STUDY DISCUSSION Cleaning and shaping is undoubtedly of paramount importance in successful Endodontic treatment. However, this does not negate the importance of the quality of obturation. This is validated by the fact that nearly 60% of failures in Endodontics can be attributed to incomplete obturation of the root canal. Hence, a three dimensional obturation is critical for Endodontic success. 30
ROOPASHREE M. S., KALA M. Chlorhexidine in the chemical form is a cationic bis-guanide that is usually marketed as gluconate salt. The substantive antimicrobial activity has been identified as a potentially protective element in the tissues for many hours after instrumentation. The potential for chlorhexidine gluconate use in Endodontics has been clearly demonstrated by numerous investigators. A possible clinical advantage of chlorhexidine gluconate over sodium hypochlorite is that, even though both are effective as antimicrobial agents, chlorhexidine gluconate is relatively nontoxic 1.However the efficacy of Chlorhexidine as an Endodontic irrigant and intra canal medicament requires further research in vivo. Nicholls stated that poor seal may lead to voids in the apical region of the canal where stagnation of tissue fluids can occur. The subsequent proteolysis and irritation can result persistence of existing periapical lesions. Traditionally, clinical emphasis has been on the apical sealing of the root canal obturation. Though a variety of new methods have come to evaluate apical seal like electrochemical methods, radioisotope tracers, fluid filtration technique still linear dye penetration is followed most commonly because of its simplicity, ease to perform and are relatively inexpensive. Longitudinal sectioning of roots and linear measurement of dye penetration were used in this study to measure apical leakage. Alternative methods are vertical sectioning or clearing the roots. Clearing technique although visually impressive has never been satisfactorily verified to completely demonstrate the pattern of tracer penetration. It is difficult to measure precisely and the tracer may be lost during the tissue processing. An effort was made in this study to balance the composition of experimental group in terms of canal anatomy. Absolute standardization is clearly impossible because of variability in canal anatomy, however relative standardization is possible, particularly of the prepared canals, in that of a standard apical size and taper can be produced. For years gutta percha has proved to be the material of choice for successful sealing of the canal from the canal orifice and the apical constriction. Though not the ideal filling material, it satisfies the majority of Grossman s tenets expected out of an ideal Endodontic obturating material. Cold lateral condensation of gutta percha is currently the most accepted obturation technique. Clearly use of such technique will not result the movement of the core filling material out of the main canal. Lateral condensation of gutta percha has remained the most widely used method of obturating root canals. This is also reflected in various dye penetration studies. Advantages of this technique include its predictability, relative ease of use, conservative preparation and controlled placement of materials. Many studies have shown that the use of sealers greatly enhances the apical seal produced by Endodontic therapy. Current Endodontic texts state that most advantageous and more predictable results are obtained if the root canal system is as dry as possible before obturation. In the present study step back preparation was followed and all the samples at the apex were enlarged to ISO size fifty. Although every effort was made to standardize the root canal preparation and 31
EVALUATION OF THE EFFECT OF CHLORHEXIDINE GLUCONATE AS AN ENDODONTIC IRRIGANT ON THE APICAL SEAL - AN IN VITRO STUDY filling techniques, it was difficult to control anatomical variations between the teeth, and this could influence the quality of the root filling. The presence of accessory canals should increase leakage while the difference in thickness of different tooth structure may affect the electrical resistance of the tooth 6. Dye penetration has been measured spectrophotometrically or linearly. Though Chlorhexidine gluconate adsorbs to surfaces covered with acidic proteins such as hydroxyapatite and is gradually released in the form of an active cat ion it did not affect the sealing ability of sealers used for obturation in this study and also it did not much contribute in the microleakage. In this study AH-Plus demonstrated better sealing ability than a calcium hydroxide based root canal sealer and Zinc oxide eugenol sealer. The sealer binds to the dentin chemically and provides a consistent apical seal and also may be due to adaptability and solubility of calcium hydroxide based root canal sealer being poorer than the other two types of root canal sealer. Chlorhexidine gluconate 0.2% root canal irrigant and AH-Plus root canal sealer combination though showed microleakage, did not affect much of the apical seal this may be attributed to adhesion of sealer with root canals. Sodium hypochlorite root canal irrigant in the concentration of 3% when used in combination of AH-Plus, Zinc oxide eugenol sealer and Metapex was not able to achieve hermetic apical seal. Normal saline 0.9% root canal irrigant when used in combination of AH-Plus, Zinc oxide eugenol sealer and Metapex root canal sealer was not able to achieve hermetic apical seal. But Normal saline 0.9% when used in combination with AH- Plus showed comparatively less microleakage. In this study there was no significant difference in the sealing abilities of the three types of sealers. An important consideration, which must not be overlooked, is that every tooth has its own configuration of the root canal system. Though this study was undertaken in single rooted teeth, the strategic position, the anatomic complexity, larger tooth pulp chamber, numerous pulp horn and wider or ribbon shaped canal orifice in multi rooted teeth makes the posterior teeth more prone to apical leakage. Also this study demonstrated no significant differences in apical leakage using three irrigants (0.9% sterile saline, 3% sodium hypochlorite, and Chlorhexidine gluconate 0.2%) and three different sealers (Zinc oxide eugenol sealer, Metapex, and Ah Plus) at 2 days observation periods. However further long term studies are required for evaluation sealing ability of sealers as well as the effect of chlorhexidine gluconate, sodium hypochlorite and saline as an Endodontic irrigants on the apical seal. SUMMARY One hundred extracted human single rooted maxillary anterior teeth were used in this study and were randomly divided into nine experimental groups of ten teeth each and a positive and negative control group of five teeth each. After decoronation of all the samples working length was determined and all the teeth were instrumented to apical file size of 50 and teeth in groups 1, 2, 3 were irrigated using sterile Saline (0.9% sodium chloride), teeth in groups 4, 5, 6 were irrigated using 3% Sodium hypochlorite and teeth 32
ROOPASHREE M. S., KALA M. in group7, 8, and 9 were irrigated using 0.2% Chlorhexidine gluconate solution. Both control groups were irrigated using sterile Saline (0.9%). Root canals were obturated with gutta-percha points using the lateral condensation technique. In groups 1, 4 and 7 Zinc oxide eugenol sealer was used, AH plus sealer was used in groups 2, 5, and 8 and Metapex sealer was used in-group 3, 6 and 9. The positive control group was obturated with guttapercha without sealer, and the negative control group was obturated using lateral condensation of gutta-percha and Zinc oxide eugenol sealer. The teeth were stored for 2 days at 37 o C and humidity to accomplish complete setting of the sealers. After 2 days all the specimens were thoroughly dried. The root surface except apical 2mm of apex was coated with two applications of nail varnish. Each coat was thoroughly dried before the subsequent one was applied. The teeth were immersed in Methylene blue 2% dye for 2 days at 37 0 C. Later the teeth were rinsed under tap water for half an hour to remove dye on external root surface. The specimens were split longitudinally. The extent of the dye penetration was evaluated visually and the depth of the dye penetration was measured in millimeters using a Stereomicroscope with an attached calibrated micrometer eyepiece and the extent of leakage was calculated and statistically analyzed using one-way ANOVA. CONCLUSION The following conclusions have been drawn from the present study. Mean microleakage value were comparatively more for groups 1 and 3 in which Normal saline 0.9% was used as root canal irrigant with Zinc oxide eugenol root canal sealer and group 6 in which Sodium hypochlorite 3% was used as root canal irrigant with AH-Plus root canal sealer, positive control group irrigated with saline and obturated without sealer. Chlorhexidine gluconate 0.2%root canal irrigant and AH-Plus root canal sealer combination did not affect much of the apical seal this may be attributed to adhesion of sealer with root canals. The positive control group irrigated with saline and obturated without sealer exhibited maximum degree of apical leakage thereby indicating a sealer to be indispensable when obturating. The negative control group irrigated with normal saline and obturated with Zinc oxide eugenol sealer also showed microleakage. Exposure of filled teeth to Methylene Blue dye followed by longitudinal sectioning proved to be an excellent means for studying apical microleakage. Though there was a difference in the mean leakage values, it was not statistically significant. The ANOVA results showed no significant difference between any groups. The result in the present study showed that Chlorhexidine gluconate did not affect much of the apical seal as compared to Sodium hypochlorite, saline and no difference in the sealing ability of sealers seen. Further long term in vivo studies are required for the evaluation of sealing ability of sealers as well as the effect of root canal irrigants on the apical seal. So to conclude, none of the groups showed hermetic apical seal. 33
EVALUATION OF THE EFFECT OF CHLORHEXIDINE GLUCONATE AS AN ENDODONTIC IRRIGANT ON THE APICAL SEAL - AN IN VITRO STUDY References 1. John T. Marley, David B. Fergusson, and Gary R. Hartwell: Effects of Chlorhexidine gluconate as an endodontic irrigant on the apical seal: short-term results. Journal of Endodontics. 2001: 27: 775-777. 2. K.C. Lim, Brian G. Tidmarsh: The sealing ability of sealapex compared with AH plus. Journal of Endodontics: 1986: 12: 564-566 3. Ludovic Pommel, Imad About, David Pashley, and Jean Camps: Apical leakage of four endodontic sealers. Journal of Endodontics: 2003: 29: 208-210 4. M.K.Wu, A.R. Ozok and P.R. Wesselink: Sealer distribution in root canals obturated by three techniques. International Endodontic Journal: 2001: 33: 340-345 5. M.K. Wu, P.R. Wesselink and Boersma: A 1 year follow-up study on leakage of four root canal sealers at different thicknesses. International Endodontic Journal: 1995: 28: 185-189 6. M.K.Wu and P.R. Wesselink: Endodontic leakage studies reconsidered. PartI. Methodology, application and relevance. International Endodontic Journal: 1993: 26: 37-43 7. Ahlberg KM, Assavanop P, Tay WM. : A comparison of the apical dye penetration patterns shown by methylene blue and india ink in root-filled teeth. International Endodontic Journal. 1995 Jan; 28 (1):30-4 8. De Almeida WA, Leonardo MR, Tanomaru Filho M, Silva LA: Evaluation of apical sealing of three endodontic sealers. International Endodontic Journal.: 2000 Jan; 33(1):25-7 9. Camps J, Pashley D: Reliability of the dye penetration studies. Journal of Endodontics. 2003 Sep; 29 (9):592-4. 10. Limkangwalmongkol S, Abbott PV, Sandler AB : Apical dye penetration with four root canal sealers and gutta-percha using longitudinal sectioning. Journal of Endodontics. 1992 Nov; 18(11):535-9. 11. Ugur Inan, Hikmet Aydemir, and Tamer Tasdemir: Leakage evaluation of three different root canal obturation techniques using electrochemical evaluation and dye penetration evaluation methods. Aust ralian Endodontic Journal 2007; 33: 18 22 12. H. ARI: Effect of moisture on the apical seal of root canal filling using Ketac-Endo and Grossman Sealer. IADR/AADR/ CADR (March 6-9, 2002) 13. John I Ingle, L K Bakland. Endodontics. 5th edition. Elsevier, 2002. 14. Stephen Cohen, Richards C Burns. Pathways of Pulp. 8th edition, Mosby; 2002. 15. Rajeswari P, Gopikrishna, Parameswaran A, and Tina Gupta, kandaswamy: In-vitro evaluation of apical micro leakage of thermafil and obtura ii heated guttapercha in comparison with cold lateral condensation using fluid filtration system. Endodontology. Vol. 17, I-2, Dec. 2005, 24-31. 34