The effect of morpholine on composite-to-composite repair strength contaminated with saliva

This study's purpose was to investigate the effects of morpholine on the chemical surface modifications of aged resin composites that had been contaminatedwith saliva on new resin composite repair ability. One hundred thirty-five resin composite specimens were prepared and thermocycled to imitate an aged resincomposite. Depending on the different surface contamination and surface treatment strategies, the aged resin composites were randomized divided into 9 groups (n = 15) as follows; group 1- no surface treatment, group 2- no saliva + adhesive agent, group 3- no saliva + morpholine + adhesive agent, group 4- no saliva + morpholine, group 5- saliva, group 6- saliva + adhesive agent, group 7- saliva + morpholine + adhesive agent, group 8- saliva + morpholine, and group 9- saliva + phosphoric acid + adhesive agent. The specimen center's top was covered with an ultradent template, and resincomposite was then filled in. The shear bond strengths and failure modes were investigated. One-way ANOVA was used to examine the data gathered, and Tukey'stest was used to assess the significant level. The statistically lowest shear bond strengths were found in groups 5 (3.31±0.95 MPa) and 6 (4.05±0.93 MPa), whilst the greatest shear bond strengths were found in groups 3 (23.66±1.35 MPa) and 7 (22.88±1.96 MPa). The shear bond strength in group 2 (16.41±1.22 MPa) was significantly different from groups 1 (9.83±1.13 MPa), 4 (10.71±0.81 MPa) and 8 (10.36±1.53 MPa), while group 9 (17.31±1.48 MPa) shear bond strength was not significantly different. In result, the shear bond strength of aged resin composites repaired with new resin composites was enhanced by applying morpholine to themeither with or without contaminated saliva before the adhesive agent application.