EFFECT OF SMEAR OFF IRRIGATING SOLUTION IN IT’S REGULAR AND NANO FORMS ON DENTIN SURFACE PROPERTIES (AN IN VITRO STUDY)

Aim: Endodontic irrigating solutions play an important role in the chemo-mechanical preparation of root canals. Exposure of root canal dentin to different irrigating solutions may impair the physical properties of root canal dentin. Therefore, many studies were conducted to address the ideal root canal irrigating solution that has the minimal effect on dentin physical properties. The aim of the present study is to evaluate the effect SMEAROFF irrigating solution in its regular and nano form on: Dentine surface properties. Materials and methods: Twenty-one extracted human non-carious mandibular premolars extracted due to periodontal problems were selected for the present study. Teeth were decoronated at the cementoenamel junction (CEJ). The working lengths of the Roots were determined, and mechanical preparation was done using Mpro rotary files sizes 20/04,25/06,30/04,35/04 and 40/04. Saline was used for irrigation during mechanical preparation. Then roots were split longitudinally into two equal halves. According to the used irrigating solution samples were divided into 3 equal groups (each containing 14 halves) as follows: Group1: SmearOFF (regular form) (N=14). Group2: SmearOFF (nano form) (N=14). Group3: NAOCL 2.6% (N=14). Determination of the surface hardness of the root dentin was measured using Vickers Hardness Tester. Statistical analysis was conducted using three-way analysis of variance (ANOVA). Results: Sodium hypochlorite (2.6%) showed the maximum reduction in dentin microhardness followed by SmearOFF in its regular form on the three levels (coronal, middle and apical) while SmearOFF in its nano form didn’t affect dentin microhardness significantly when compared with the pretreatment measures for the same group. Dentin microhardness values were highest at the coronal level followed by the middle third then the apical third showed the minimal microhardness values for the three groups. Conclusion: Within the limitation of the present study, it can be concluded that the use of nano SmearOFF in the final rinse protocol is less detrimental to radicular dentin microhardness when compared to other irrigating solutions used in the present study.