A spectro photometric comparative evaluation of apical sealing ability of three different sealers; calcium hydroxide based, resin based and zinc oxide eugenol based sealers.

BACKGROUND: The aim of this study was to quantitatively analyze the amount of dye leakage with AH26, Sealapex and Tubliseal sealers in endodonticaly treated teeth.
MATERIALS AND METHODS: A total of 36 extracted mandibular molar specimens were divided into three groups; Group I: Sealapex, Group II: Tubliseal, Group II: AH26 with 12 samples in each group. Standard access cavity and biomechanical preparation was done with step back flare technique. Obturations were done using respective sealers in the three different groups. Then, samples were subjected to spectro photometric analysis using a filter of 670 nm. Spectrophotometric analysis was performed to quantitatively analyze the amount of dye leakage with all three sealers.
RESULTS: Tubliseal exhibited the least microleakage. In comparison to Sealapex, Tubliseal showed a significant difference. Compared to Sealapex, AH26 showed no significant difference. Comparisons made between Tubliseal and AH26 showed no significant difference.
CONCLUSION: In the present study, Tubliseal sealer showed least microleage compared with Sealapex and AH26 sealer.

Introduction

Microleakage between the root canal filling and root-canal walls may adversely affects the results of root-canal treatment.1

Apical leakage is considered to be common cause of endodontic failure.2 Hence, different endodontic filling materials, sealers and techniques have been introduced to the dental community in an attempt to improve apical seal.1 Various materials have been used in root canal treatment in an attempt to achieve success. But, a combination of Gutta-percha and a sealer are used most commonly. Gutta-percha is considered an impermeable core material; therefore, leakage through an obturated root canal is expected to take place at the interfaces between the sealer and dentin or the sealer and gutta-percha, or through voids within the sealer.3 Apical sealing is desirable to prevent passage of bacteria and their endodotoxin apically. In vitro evaluation of apical dye penetration is used to estimate the sealing ability which is corresponding to in vivo amount of micro leakage with particular sealer.2 Many techniques were used to evaluate the leakage of sealers such as; colored dye penetration radio labeled tracer penetration dissolution of hard tissue clearing of teeth, spectrometry of radioisotopes electrochemical and gas chromatography. However, many studies showed no significant difference between these techniques.1

The aim of this in vitro study was to quantitatively evaluate the sealing properties of three different root-canal sealers; Tubliseal, Sealapex and AH26 using a spectrophotometric method.

Materials and Methods

Thirty-six extracted sound mandibular molar natural teeth specimens with complete root and free from caries or cracks were collected, stored, disinfected and handled as per the recommendations and guidelines laid down by Occupational Safety and Health Administration and Centers for Disease Control and Prevention.4 The teeth were then placed in 0.9% physiologic saline solution for ten days prior to access cavity preparation. The samples were divided into three experimental groups; Group I: Sealapex, Group II: Tubliseal and Group III: AH26 with 12 samples in each group.

Standard access cavity and biomechanical preparation with step back flare technique were done. Obturations were done using respective sealers in the three different groups. The samples were then coated with nail varnish all over the root surface except 2 mm around the apical foramen. 2 ml of freshly prepared 2% methylene blue dye was taken in each vial and the apical third of the root was suspended in the dye for 72 h. Samples were washed with distilled water, nail varnish removed and then placed in 20 ml of 35% nitric acid for 72 h. Standard solutions of 1%, 0.5%, 0.2%, 0.05%, 0.02% and 0.01% of methylene blue in 35% nitric acid were prepared and stored for 72 h. The Standard solutions and the nitric acid solutions were filtered and centrifuged for 1 min after 72 h. The supernatant was subjected to spectrophotometric analysis using a filter of 670 nm. The amount of leakage was extrapolated from a standard linear regression curve constructed from stock standard methylene blue dye solutions. Obtained data were statistical analyzed with Kruskal–Wallis and Mann–Whitney U-tests using SPSS Software Version 20 (IBM).

Results

The results of the quantitative evaluation of the sealing properties of the three root-canal sealers are shown in Table 1. Table 2 and Chart 1 show intra group comparison of micro leakage of sealers. Tubliseal exhibited the least microleakage (Table 1). In comparison to Sealapex, Tubliseal showed a significant difference (P > 0.005). In comparison to Sealapex, AH26 showed no significant difference. Comparisons made between Tubliseal and AH26 showed no significant difference (Table 2, Chart 1).

Table 1

Mean and standard deviation values of volumetric dye penetration in groups with reference to transmission.

Table 2

Inter group comparison for dye penetration.

Chart 1

Inter group comparison chart for dye penetration of different sealers.

Discussion

Three-dimensional obturation of the root canal system with a fluid impervious seal is an important factor for successful endodontic therapy. The root canal filling should seal the canal both apically and coronally to prevent the passage of microorganism to apex or vice versa.5 Most reliable method is the use of gutta-percha cones with sealer cement. A wide variety of root canal sealers is available commercially. Sealers based on zinc oxide-eugenol (Tubliseal), calcium hydroxide (Sealapex), epoxy resins (AH26) were included in the present study.

In present quantitative dye leakage study, Tubliseal demonstrated least dye leakage in comparison with other experimental groups (Table 1). There was a significant difference between Sealapex and Tubliseal (Table 2). Our results were in contrary to study by Masoud and Saleh where they found more microleakage in Tubliseal group than other groups.6

Sealapex is a calcium hydroxide type sealer. Calcium hydroxide used as root canal sealer since it stimulates periapical tissues in order to maintain health or promote healing and secondly for its antimicrobial effects.7 It has been observed in some studies that, calcium hydroxide sealers showed a significant volumetric expansion during setting because of water absorption, which increases its solubility. The present in vitro investigation indicated maximum leakage value with Sealapex among the experimental groups. In a contradictory to our results, Cobankara et al. (2006) observed Sealapex with better apical sealing than the other sealers (AH plus and RC sealer) at 7, 14, and 21 days.3

AH26 is an epoxy resin based sealer that provides easy handling characteristics, good flow, good sealing to dentin and prominent antimicrobial activity.6 Kumar et al. observed more micro leakage with zinc oxide-based sealer and least with resin based sealers, this is contradictory to our study.8 In our study, there was no statistical significant difference between Tubliseal and AH26 in micro leakage. Gernhardt et al. observed least amount of dye penetration for AH Plus and EndoRez group.9

Even though, the current study did not indicate any statistically significant difference between AH26 and Sealapex, it is time to question the overall efficacy of calcium hydroxide sealers on the grounds that the reparative and the calcification capabilities attributed to calcium hydroxide are generally desirable before completing the obturation. AH26, resin based sealer provided a better apical seal when compared with Sealapex even though the results were statistically not significant. AH26 appears to have many advantages over other sealers. It mixes easily, flows well, and has ample working time, good radio-opacity, comparable solubility, good adhesion and good biocompatibility.3

In the present study, there was no significant difference between Group II and III and Group I and III. This is in agreement with De Almeida et al.10 Silva et al. didn’t find any significant difference between the tested three groups; sealer 26, Enfoflas and resin group. But they observed higher microleakage in sealer 26 group compared with control.11 Joseph and Sing evaluated the apical sealing with four root canal sealers; AH26, Sealapex, Endoflas FS and AH Plus and observed no significant differences between all groups except between AH Plus and Endoflas.5 Nagas et al. observed significantly lower overall leakage with AH plus group, whereas no difference was found between master cone points.12 Kopper et al. observed significant dye penetration for AH Plus, Endofill and Sealer 26.13

Cobankara et al. observed better sealing values for RoekoSeal after 21 days when compared to Ketac-Endo and AH Plus, and there was no statistically significant difference.1 Dultra et al. found no statistical difference between groups for apical leakage (Endofill, AH Plus, EndoRez and Epiphany).14

In addition, before accepting a new material for routine clinical use further experiments should also be performed to evaluate the other aspects of the materials’ physical and biological properties such as biocompatibility, solubility, disintegration, radio-opacity and dimensional stability. However, these in vitro studies do provide comparative information of the relative performance of sealers tested under the same conditions in each particular study and clinicians can use this information to possibly choose a better sealer.

Conclusion

In the present study, Tubliseal sealer showed least microleage compared with Sealapex and AH26 sealer. However, there was a significant difference between Sealapex and AH26 groups. It is important to remember before declaring any root canal sealer as most acceptable that the results of the dye penetration studies indicate only the relative sealing ability of root canal fillings in vitro and they do not indicate their ability to prevent the penetration of bacteria into filled root canals in vivo.