In Vitro Comparative Evaluation of the Physical and Mechanical Properties of Two Soft-liners Coated with Different Types of Coatings.

Abstract

Aim: To evaluate the changes on the physical and mechanical properties of acrylic and silicone based soft liners after applying four different types of coatings.

Methods: A total of 50 samples were prepared and divided into two major groups viz. Group A-Exact-On (30 samples) and Molloplast-B (30 samples). Group A and B were further subdivided into 5 subgroups l,ll, lll, lV and V containing 6 specimens each. The samples were coated with four different types of coatings and were compared to the uncoated control group (subgroup). Main composition of two types of Monopoly were chemically activated methylmethacrylate monomer, clear methylmethacrylate polymer, heat activated methylmethacrylate monomer. Two new types of coatings were made with n-butyl cyanoacrylate.These two coatings were never tried before in any literature review.The coated samples were tested for Hardness, Permanent deformation, Tensile strength, Water absorption determination and the coated surfaces were observed under SEM and compared with the uncoated control group.

Results: Molloplast-B, a silicone based had longer shelf life but a coated acrylic based liner was seen to be equally good. Cyanoacrylate monomer coating and self cure monopoly coating were superior to other coatings. All results were statistically analyzed by 2-way ANOVA. The mean values for hardness ranged from 24.t6 to 29.33 Shore A for Group A and 41.50 to 42 Shore A for Group B. Values of permanent deformation ranged from 1.01 to 0.93%for the Exact-On (Group A) and 0.158 to 0.140 % in coated Molloplast-B samples (Group B). Mean values of Tensile strength ranged from 5kg/cm2 to 6.00kg/cm2 in Group A and i.6.33 kg/cm2 to t7.67kg/cm2 in Group B. It was observed that among the coatings Cyanoacrylate Monopoly coating was more efficient in preventing water absorption and leaching followed by Cyanoacrylate Monomer coating.

Conclusion: None of the coatings affected the physical properties of tissue conditioners. All coatings prevented water absorption from tissue conditioner and prolonged the life of tissue conditioner.