Comparing Shear Bond Strength Of Auto-polymerized Soft Lining Materials to Acrylic Denture Base Using Different Surface Treatment and Denture Base Materials

Background: Denture bearing tissue condition may be highly affected by stress applied from the occlusal force during function of mastication therefore the need for denture soft lining material application is necessary and testing the bond strength of this material to acrylic denture base is of some point of interest and need to be improved. The aim of the study is to test the shear bond strength of soft lining materials to the denture base after surface modifications and using different denture base materials. Materials and Methods: 120 samples included in the study to test the shear bond strength, sample grouped according to surface treatment of acrylic resin (Control without surface treatment, monomer surface treatment, Nd-Yag laser surface treatment (10 Hz and 20 Watt) and Nd-Yag laser surface treatment (10 Hz and 40 Watt)) with different denture base materials used (High impact acrylic, Heat cured acrylic and light cured acrylic), the shear bond strength test was made by using universal testing machine with cross head speed 40 mm/ min the force required for soft lining material complete separation from the acrylic resin materials calculated. Statistical analysis made by SPSS software analysis using ANOVA Table with LSD multiple Comparison.  Results: the highest value of shear bond strength found in group with high impact acrylic and 2nd dose of laser treatment applied, while the lowest one found In a group of light cured acrylic when 1st dose of laser treatment used. the comparison among groups made by using ANOVA Table with LSD which revealed that there was a highly significant difference between all groups with different surface treatments except heat cured and light cured groups. A highly significant difference also found between 2nd dose of laser treatment and control, monomer and 1st dose of laser surface treatment when different materials used.  Soft lining materials, denture base, Laser, Monomer. High impact acrylic, light cured acrylic. 2nd dose of laser surface treatment when 10 Hz and 40 Watt of Nd-Yag Laser applied Show the highest value of shear bond strength in high impact acrylic group, while the lowest value was recorded in light cured acrylic with 1st does laser treatment.