The Effect Of Four Endodontic Irrigants on the Shear Bond Strength of a Self Etch Resin Based Sealer to Dentin: An Invitro Study

The present in vitro study was undertaken to evaluate the effect of four different irrigants namely Sodium hypochlorite, Chlorhexidine, Triphala and Morinda citrifolia on the shear bond strength of a self etch sealer, Real Seal SE to dentin by using with and without EDTA as the final irrigant using an Universal Testing Machine. The study was done using one hundred and twenty extracted maxillary and mandibular human molars. A low speed diamond disk saw with Water coolant was used to slice off the occlusal 2mm of the samples whereby a flat dentinal surface surrounded by a thin rim of enamel was obtained. This section of tooth, which included the roots, were embedded in a self cure acrylic resin. A smear layer was created on the sectioned teeth using a 320 grit silicon carbide paper on a Handimet grinder (Buehler, Ltd) under Water irrigation for a time period of 15 seconds. The dentin disks with the smear layer were then randomly divided into 2 groups namely Group I-without EDTA and Group II-with EDTA. Each of the Group was further divided into four Subgroups namely Sodium hypochlorite, Morinda citrifolia, Triphala and Chlorhexidine respectively. The dentin discs were air dried using a air-water syringe. A brass tube of 4mm internal diameter and 3mm height was placed onto the dentin surface. The brass tube was filled with Real Seal SE, (Fig.4H) which was mixed according to the manufacturer’s instructions. The sealer was then light cured using a light curing unit (QHL-75,Dentsply) for 40 seconds and allowed to set for forty five minutes. The samples were immediately stored in distilled water at 37oC and maintained at 100% humidity for 7 days. The specimens were then engaged perpendicularly at their bases on a Universal Testing Machine (INSTRON 3365). Each specimen was evaluated for its shear bond strength values, at a cross head speed of 1mm/minute. The shear force required to separate the cylinder from dentin was recorded in Newtons (N) for each specimen, then divided by contact surface area to determine the shear bond strength in Megapascals. The results were then statistically analyzed using a paired One way ANOVA, Students ‘T’ test and Duncan’s Multiple Range Test. The results revealed that Subgroup Sodium hypochlorite had the highest shear bond strength in Group I (without EDTA) and Group II (with EDTA) followed in order by Subgroups Morinda citrifolia, Triphala and Chlorhexidine in both groups. When both Group I and Group II were compared, the Group II (with EDTA), all the Subgroups showed highest bond strength to dentin with resin sealer (Real Seal SE). CONCLUSION: Within the limitations of the study it can be concluded that 1. Sodium hypochlorite Subgroup in both the Group I (without EDTA) and Group II (with EDTA) showed the maximum shear bond strength values. 2. Chlorhexidine Subgroup in both the Group I (without EDTA) and Group II (with EDTA) showed the minimum shear bond strength values. 3.Triphala and Morinda citrifolia Subgroups showed shear bond strength values more than Chlorhexidine but less than Sodium hypochlorite in both the groups. 4. Triphala and Morinda citrifolia could be used as herbal alternative irrigants during the cleaning and shaping of the root canals. It is seen that they are as effective but are less toxic and more biocompatible than the traditionally used irrigants. 5. Further studies with more parameters are necessary to validate these results and to determine the suitability of this material for invivo use