Comparing the Shear Bond Strength with Acrylic Teeth, Hardness, Surface Roughness and Cost-benefit of three Different Denture Base Materials

One of the major problem affecting the denture function is the detachment of the artificial teeth from denture as a result to the higher chewing capacity that will rise the risk of artificial teeth displacement. Displacement of the teeth may precede by changing in the material properties affecting the denture function that is why surface roughness and hardness considered as a predictor for the material behaviors and performance. Replacing a denture may cause a burden to the patients, hence, the material and fabrication coasts of dentures should be considered as one of the major factors affecting the selection of the denture base material, as in some cases a base material with impressive propertied limitedly used because of its expenses.[1] In this study, shear bond strength with acrylic teeth, hardness, surface roughness and the net benefits, associated with alternatives for achieving defined treatment objective, were evaluated by comparing some properties of three different denture base materials with the cost of each one in Iraq. A total of (90) specimens of polycarbonate, injectable acrylic and conventional heat cured acrylic were fabricated according to manufacturer’s instructions and divided into (3) groups, (30) specimens for each testing group i.e. the shear bond strength with acrylic teeth, shore D hardness and surface roughness (10 specimens for each testing material). the total cost of each specimens group was collected and calculated to evaluate the overall cost benefit of each material. Highly significant differences (P≤ 0.01) between all the (3) experimental materials were noticed after analyzing each test's results with descriptive statistical analysis, one-way ANOVA and post-hoc LSD, except for the shore D hardness whereas a non-significant differences(P> 0.05) between heat cured and injectable acrylic was found. The heat cured acrylic has the highest mean value of the shear bond strength with acrylic teeth (516.1 N) followed by the injectable acrylic with (329.9 N) mean value while the lowest mean value was for the Polycarbonate (180.1 N). Furthermore, the injectable acrylic has the highest mean value in shore D hardness (91.96), followed by the heat cured acrylic (91.5), then Polycarbonate (82.94). As for surface roughness, the Polycarbonate has the highest mean value (0.31703) followed by the injectable acrylic (0.2129), then the heat cured acrylic (0.10367). Finally, Polycarbonate has the highest mean value of the specimens’ cost in Iraq (10.022 US dollar /specimens), followed by the injectable acrylic (8.695 US dollar /specimens) then the heat cured acrylic (3.243 US dollar /specimens). All thermoplastic materials included in this study (Injectable acrylic and Polycarbonate) exhibited higher cost with lower properties in comparison with heat cured acrylic material for the selected tests.