بررسي مقايسه اي استحكام ميكروبرشي S.E Bond در نواحي مختلف عاج دندان شيري

Comparison of regional microshear bond strength of S.E Bond to primary teeth dentin

Background & Aim: This study was carried out to compare the microshear bond strength of Clearfil SE Bond between the two different regions of primary tooth: incisal and cervical. Methods & Materials: In this experimental study which was controlled in vitro trial, 20 extracted primary canines without any caries, fracture and structural anomalies were disinfected and stored in normal saline of a room temperature. Every tooth was hemisectioned buccolingually via ground section. From the two resultant mesially and distally sections, one was chosen for the test, randomly. The composite resin material (Ap-x;A2) was placed and packed into the micro bore tygon tubing with the height of 1 mm and internal diameter of 0.7 mm. After application of self - etching primer (according to the manufacturersʹ instructions) over the incisal and cervical (buccal aspect) dentin, tygon tubes containing composite, were placed over these areas and cured for 40". Microshear bond strength was determined using the microshear machine and also mode of failure was investigated by stereomicroscope in addition. From incisal and cervical regions of primary canines, two specimens were chosen randomly to investigate the dentinal tubules orientation in these regions by SEM. Results: SEM observations revealed that the dentinal tubules were oblique, both in incisal and cervical, so there was no difference in dentinal tubules orientation between these two regions. Mean microshear bond strength was 33.88±10.67 MPa for incisal and 28.79±11.72 Mpa for cervical region. Adhesive failure was the most predominant mode of failures being observed in both regions. Conclusion: There was no statistically significant difference in microshear bond strength of Clearfil SE Bond between the incisal and cervical dentin in primary tooth.