ABSTRACT
Background: The depletion of bond strength after the bleaching procedure has resulted in the usage of several antioxidants to get rid of discharging oxygen from residual peroxides before any adhesive restorations. Aim: The in vitro study aimed to compare and evaluate the shear bond strength of composite after application of three over-the-counter natural antioxidants on bleached enamel. Materials and Methods: Thirty-six extracted human anterior teeth were decoronated at the level of cementoenamel junction and implanted into self-cure acrylic resin exposing the labial surface alone. The embedded specimens were categorized into six groups of six teeth each, and the groups were as follows: Group I: unbleached + composite bonding, Group II: bleaching + delayed composite bonding, Groups III, IV, and V: bleaching + antioxidants - olive oil/Vitamin E oil/propolis + immediate composite bonding, and Group VI: bleaching + immediate composite bonding. The shear bond strength analysis was performed with the help of the universal testing machine, and the values obtained were statistically analyzed using IBM SPSS for Windows, v. 21.0. Results: The results obtained from the study reveal that all the three experimental groups showed an increase in the shear bond strength in comparison to Group VI (positive control) and the difference in the bond strength between the experimental groups and positive control is also statistically significant. Conclusion: Within the limitations of this study, although the bond strength of composite resin after application of the three natural over-the-counter antioxidants falls very closely, the usage of oil-based antioxidants had been found to perform less effectively in improving the shear bond strength.
ABSTRACT
Aim This study aims to compare and evaluate the efficacy of four different irrigating solutions like sodium hypochlorite, ethylenediaminetetraacetic (EDTA), Oxum, and ozonated water with ultrasonic agitation in removing the smear layer in the apical third of root canals using Scanning Electron Microscopy (SEM). Materials and methods For the study, 50 freshly extracted human mandibular premolars with single well-developed roots without any curvatures were taken. The teeth taken were decoronated to obtain a uniform working length of 15 mm, and the samples were instrumented using a ProTaper Gold rotary file system (Dentsply Maillefer, Ballaigues, Switzerland) up to F2 size, along with irrigation of 1 ml of 3% sodium hypochlorite (NaOCl) in between instrumentation. The samples were randomly divided into five groups with 10 samples each, according to the final irrigant used. Group I-EDTA 17%, Group II-NaOCl 5%, Group III-Oxum, Group IV-ozonated water, and Group V-normal saline. In all groups, ultrasonic agitation of the irrigating solution was performed using a size 20 file, held passively inside the root canal. Then the samples were flushed with distilled water, dried with paper points, split into two halves, and subjected to SEM analysis. SEM images of the apical third region of root samples were taken at 5000X resolution and scored on a scale of 1 to 4. Results Statistical analysis was done using one-way ANOVA followed by Tukey's post hoc test using software version SPSS software version 17.0 (SPSS Inc., Chicago). The results showed that the 17% EDTA group showed the least smear layer scores when compared to other groups with statistical significance. This was followed by the Oxum group and 5% NaOCl group, whereas the ozone water group and saline control group showed the highest smear layer scores. Conclusion The present study reveals that the EDTA is the superior irrigant in the elimination of smear layer in root canal treatment. Newer irrigants, such as Oxum, can be used as an alternative to EDTA for smear layer removal while remaining biocompatible with dentin. Whereas ozone can be combined with other irrigants for synergistic action of enhanced antimicrobial property and smear layer elimination in the future.
