A successful composite restoration depends on the adhesive composite forming a strong, durable bond between the composite and the dentin. However, the use of sodium hypochlorite for biomechanical preparation of root canals changes the structure of dentin surface and partially removes collagen fibrils, affecting the interaction with adhesive restorative materials. Many studies demonstrated that NaOCl reduces bond strength between composites and dentin.[1], [2], [3] The compromised bond strength to NaOCl treated dentin could be restored by the application of an antioxidant agent before the adhesive procedure. Sodium ascorbate is the most studied antioxidant agent. [4], [5] But, Erhardt et al showed that sodium ascorbate may either compromise or enhance the degradation of composite dentin bonds over time, depending on the adhesive used.[4] So, there is an increased interest in evaluating new substances to neutralize effects of oxidative compounds.
Aim
To Compare and evaluate the effect of Grape seed Extract, Propolis and Vitamin E on the Bond strength of NaOCl treated dentin
Materials and Methods
Non carious human mandibular first molars collected
Figure 1 : Specimen: Human molars
Inclusion criteria
Non carious mandibular first molars with intact crown and root.
Exclusion criteria
Teeth with Caries, Fractures, Craze lines, Development defects
Preparaton of 5% propolis
5g propolis powder + 100mL of distilled water
Figure 2 : Preparation of 5% propolis
Preparaton of 5% grape seed solution (OPC’s)
5g of Grape Seed extract (powder) + 100mL distilled water
Figure 3 : Preparationof 5% grape seed solution
Occlusal surfaces of the teeth were flattened, which eliminates the pits and grooves. Standardized class I cavities were prepared on occlusal surfaces of tooth with following dimensions.
4mm-wide (bucco-lingual))
4mm-deep (occluso-gingival)
4mm-long (mesio-distal)
Using ISOsize (NO.001) round bur and ISO size (NO.112) straight fissure, under copious water coolant in a high speed hand piece.
Figure 4 : Measurement of the specimen using Digital calipers
Teeth were randomly divided into five groups of 10 teeth each depending on the agent used.
Group I - Negative control group
Group II - Positive control group
Group III – Propolis
Group IV - Grape seed Extract
Group V – Vitamin E
After surface treatment of teeth in each group with different agents, adhesive system (Fusion bond 7) was applied to the surface of the cavities, as per the manufacturer’s instructions. After bonding procedure, all teeth received a Nanohybrid composite restoration (Ivoclar) in increments. Each increment was light cured for 40 seconds using a light curing unit set at 1200mW/cm2.
Figure 5 : Placement of adhesive restoration and curing
To perform the bondstrength test, specimens were sectioned through centre of the restoration (both buccoingually and mesiodistally) with a water cooled slow speed diamond disc that resulted in four resin-dentin specimens from each tooth.
Figure 6 : Sectioned specimens
All the specimens were mounted in acrylic tube or mold (20 mm height &10 mm diameter) with an auto-cure acrylic resin. The root was positioned at the centre of the acrylic tube vertically; with only crown portion exposed and allow the acrylic to set completely before doing the test.
Measurement of bond strength
The Compressive bond strength values were measured with a Universal Testing Machine. A knife-edge shearing rod was used at a crosshead speed of 1 mm/min, until failure. The values of the specimens were calculated and expressed in MPa.
Results
One way ANOVA test was done for statistical analysis
Graph 1 : Bond strengths of different groups
The data were tabulated and statistically analysed using analysis of variance (ANOVA) test to compare the SBS between five groups. The selected level of variance was 0.05. ANOVA showed a significant difference in mean SBSs at P < 0.05. The mean SBS of all five groups was highest in Group III and was least in Group II
Discussion
In this study, the effects of Propolis, grape seed extract, Vitamin E on bond strength of self-etch adhesive to dentin are evaluated. The use of NaOCl for root canal preparation may negatively affect bond strength of post endodontic restoration of composite to dentin.[1] The current study found a reversal effect on bonding comprimised by NaOCl treatment by Antioxidants. Antioxidants can act in three different ways. [6]
Free radical chain breaking
Metal chelating
Free radical quenching
Propolis, Also called as the Bee Glue, derived from the salivary secretion of the Honey Bees.It has Free radical scavenging ability, Anti-viral, anti-bacterial & anti-fungal agent, Anti-inflammatory action.[4], [6], [3] Proanthocyanidins, extracted from Grape seed are known to increase dentin matrix mechanical properties, decrease extracellular degradation by inhibhiting proteases and also have antioxidant and antibacterial properties.[2] Vitamin E is proven to have antioxidant property. [7]
Reasons for high bond strength in Group III (Grape seed)
The presence of multiple donor sites on OPCs that trap superoxide radicals.[8]
More affinity towards free hydroxyl radicles.
Higher bond strength for propolis than control group & group V
Grape Seed Extract, Propolis and Vitamin E increased shear bond strength of the composite restoration to NaOCl treated dentin. Treatment with antioxidants gave bond strength superior to that of untreated dentin. They allow free radical polymerization of adhesive resin without its premature termination.
Conflict of Interest
The authors declare that there is no conflict of interest.
Source of Funding
None.
References
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