An In Vitro Scanning Electron Microscopy Study to Evaluate the Dentinal Tubular Penetration Depth of Three Root Canal Sealers

Background: It is difficult to identify a potential sealant with penetration depth until practically analyzed. A scanning electron microscopy (SEM) overview could better describe the internal picture of the materials sealed to the tooth surface on in vitro experimentation since it being a vital procedure for successful obturation. Hence, this study was undertaken to compare the penetration depth of three root canal sealers most commonly available viz., AH Plus® (Dentsply, New Delhi, India), TubliSealTM (Kerr Dental, New Delhi, India), and Apexit® Plus (Ivoclar Vivadent, New Delhi, India) with different compositions using SEM. Materials and Methods: A total of 30 single-rooted mandibular premolars decoronated and the canal preparation done by step back technique was used for this study. 17% of ethylenediaminetetraacetic acid (EDTA) used as final flush. Prepared specimens were divided into three groups of 10 teeth each, and different sealers were used for each group (zinc oxide eugenol-based Tubli-SealTM, calcium hydroxide-based Apexit® Plus, and resin-based sealer AH Plus®). After obturation, teeth were split longitudinally and viewed under SEM. Results: There was no statistically significant difference among the means of measured depth of penetration of AH Plus® and Apexit® Plus sealer. However, Tubli-SealTM values projected statistically significant differences in comparison to AH Plus® and Apexit® Plus sealer. Means of measured depth of penetration of different sealers were subjected to one-way ANOVA and Duncan’s multiple range test with a statistical significance at < 0.001. Conclusion: Zinc oxide eugenol-based sealer (Tubli-SealTM) shows less depth of penetration as compared to the calcium hydroxidebased sealer (Apexit® Plus) and resin-based sealer (AH Plus®). Key Words: Canal sealer, electron microscopy, root canal, root canal filling materials, sealants Introduction The root canal therapy success lay with the instrumentation, disinfection, and three-dimensional obturation of root canal system. Obturation plays a vital role of all the factors contributing to the success of therapy. Sealers have become an integral part of obturation process which improves the quality of obturation. The ability of root canal sealers to adhere to dentin and gutta-percha results in superior sealing ability, which in turn reduces microleakage and improves the quality of obturation.1 Deeper the penetration of the sealer into the dentinal tubule better the sealing achieved. Thereby the retention of material is enhanced by mechanical locking. The smear layer prevents penetration of root canal sealer into the dentinal tubules.2-5 Thus, removing the smear layer would increase the chances of sealer penetration into the dentinal tubules. The penetration of the sealer into the dentinal tubule is of increasing clinical importance since there is no chemical adhesion between dentin and different types of sealers. It has been suggested that a mechanical interlock for lack of chemo-adhesion through dentinal tubular penetration may be the solution. However, penetration mainly depends on the rheological properties and setting time of the sealer material used for obturation. A large variety of sealer materials are available within the fraternity with all proposed best properties of sealing. It becomes difficult to identify a potential sealant with penetration depth until practically analyzed. A scanning electron microscopy (SEM) overview could better describe the internal picture of the materials sealed to the tooth surface on in vitro experimentation. Hence, this study was undertaken to compare the penetration depth of three root canal sealers most commonly available viz., AH Plus® (Dentsply, New Delhi, India), Tubli-SealTM (Kerr Dental, New Delhi, India), and Apexit® Plus (Ivoclar Vivadent, New Delhi, India) with different compositions using SEM. Materials and Methods About 30 caries free single-rooted human mandibular premolars freshly extracted for the therapeutic purpose were used for this study. Teeth with similar root canal anatomy were selected with the help of radiograph. Those specimens selected were stored in saline at room temperature. De-coronated at the cement-enamel junction using diamond discs to facilitate instrumentation. Those specimens in which #20 K file was binding at the apex and just visible at the apical foramen were only selected, and the rest got replaced with new specimens.