Effect of thermocycling in a hard denture liner and acrylic resin after different chemical and mechanical polishing

Objective To evaluate the effect of aging in a hard denture reline (New Truliner) and an acrylic resin (Classic) after chemical and mechanical polishing. Methods Eighty specimens were made, divided randomly between 8 groups: G1.Acrylic Resin Classic (RAC)/Mechanical Polishing (PM); G2.RAC/PM + thermocycling (TR); G3) RAC/Chemical Polishing (PQ); G4.RAC/PQ + TR; G5.New Truliner (NT)/PM; G6.NT/PM + TR; G7. NT/PQ; G8.NT/PQ + TR. The surface hardness was measured before and after polishing, and after TR. The impact resistance tests were measured after all applied treatments. The data were submitted to ANOVA and Tukey test (α=5%). Results Regardless of the polishing, it was noted that RAC presented significantly higher surface hardness than NT; PM had higher hardness in both materials compared with PQ; on both polishing, the impact resistance of the RAC was higher than NT. Independently of TR test, the impact resistance of the materials that received PQ was higher than received PM. The PQ caused greater changes in properties than the PM. Conclusion Aging and chemical and mechanical polishing influenced the physical and mechanical properties of hard denture reline and acrylic resin. Indexing terms: Acrylic resins. Aging. Denture liners. Hardness.