Determination of adhesive characteristics of creams for fixing removable dentures

Oral diseases remain a global health problem, and with the continued high prevalence of adentia, the key unresolved issue remains improving the fixation efficiency of removable dentures using adhesive materials. The aim is to evaluate the adhesive strength of dental creams to polymethyl methacrylate and photopolymer used in the technology of removable dentures. Materials and methods. The tests involved 9 samples of dental cream: 5 samples of Corega of different compositions and 4 other samples. The adhesive strength of dental creams was compared when two surfaces were glued together: the first surface was silicone rubber, and the second surface (substrate) was polymethyl methacrylate (PMMA) or a photopolymer for additive manufacturing of removable dentures bases (3D). The shear, tensile, and peel strengths were measured. A total of 11 experiments were conducted, including tests to determine the onset of adhesion and the optimal thickness. Results. The best shear results were shown by the “PresiDENT” samples for PMMA and “Corega: maximum fixation + comfort” for 3D photopolymer (2.24 and 2.12 kPa), the “Whiteberg” samples for PMMA and “Corega maximum fixation + comfort” samples for 3D photopolymer (30.3 and 28.7 kPa), for rupture. The separation is a “Whiteberg” sample for both PMMA structural materials and a photopolymer (1160 and 1158 kPa). In experiments to determine the onset of adhesion (after exposure for 3 minutes) and the completion of adhesive strength (after exposure for 12 hours), a higher strength value was also found in the “Whiteberg” sample (PMMA and 3D), in the Corega segment — samples with the composition “extrasensory fixation” (PMMA) and “maximum fixation + comfort” (PMMA and 3D). The assessment of the adhesive strength of creams depending on the thickness of the studied layer showed that in the presence of a gap of 100 microns, the value of the indicator in all samples drops sharply and then weakly correlates with an increase in the gap. Conclusions. Among Corega creams, the cream “Maximum fixation + comfort” showed the best result in shear and tear tests. In tear tests, two formulations are characterized by the same strength — “Maximum fixation + comfort” and “Extra-strong fixation”. Of the formulations from other manufacturers, 2 creams showed results comparable to Corega in all tests — these are “Whiteberg” and “PresiDENT”.