Surface Roughness of Auto Polymerized Acrylic Resin According to Different Manipulation and Polishing Methods

Abstract

Objective: To test the hypothesis that no differences exists in the in situ level of surface roughness of an auto polymerized acrylic resin irrespective of the method of manipulation and polishing. Materials and Methods: Forty volunteers received the test specimens. Surface roughness was evaluated using a rugosimeter. Samples of auto polymerized acrylic resin were submitted to two methods of manipulation-mass and addition-as well as to two types of polishing-mechanical and chemical. Four test groups were designated according to manipulation and polishing techniques: mass-mechanical, mass-chemical, addition-mechanical, and addition-chemical. Five measures of surface roughness were taken from each sample and average surface roughness (Ra) was determined before and 20 days after the samples were worn by the volunteers. The data obtained were analyzed by the Student's t-test for paired samples as well as by analysis of variance. Results: Significant differences in Ra were found between mechanical and chemical polishing. Surface roughness was not influenced by manipulation techniques. Mechanical polishing presented the lowest values of Ra. There was a significant increase in surface roughness after volunteers wore the specimens for 20 days. Conclusions:The hypothesis is rejected. There were differences on the surface roughness according to the different methods of manipulation and polishing used, but high values of surface roughness were found for all groups. Mechanical polishing showed the lowest values of surface roughness and thus should be preferred.

Surface roughness of two Polyamide Material Types Used in the Manufacture of Denture Base Compared with a Type of Heat-cured Acrylic Resin

“…As in all previous investigations, roughness of PMMA has been clinically acceptable (4)(5)(6)(7)(8)(9); probably this difference may reflect the insufficiency of manual polishing in our laboratories.…”

Mechanical and Biological Properties of Acrylic Resins Manipulated and Polished by Different Methods

“…Chemical polishing has shown higher surface roughness than the mechanic, influencing more the mechanical and biological properties of resins, either for microorganism accumulation or residual monomers release (11), which may be related to greater incorporation of monomers during chemical polishing.…”

“…Furthermore, polishing is an important factor for obtaining smooth surfaces of the acrylic resins, which favors the reduction of the amount of released residual monomer (10,11). Chemical polishing has shown higher surface roughness than the mechanic, influencing more the mechanical and biological properties of resins, either for microorganism accumulation or residual monomers release (11), which may be related to greater incorporation of monomers during chemical polishing.…”

Effect of finishing and polishing methods on surface roughness of autopolymerized acrylic resins

“…In view of this, in order to avoid the loss of prosthetic pillars and adjacent teeth to periodontal disease or caries, smooth well-finished parts are extremely important, in addition to making the element esthetically acceptable [6][7] . Thus, finishing and polishing techniques need to be established reconciling the use of accessible materials, reduction in clinical time and the attainment of less surface roughness 6 .…”

“…Thus, finishing and polishing techniques need to be established reconciling the use of accessible materials, reduction in clinical time and the attainment of less surface roughness 6 . Accordingly, in order to achieve adequate surface smoothness, there are two forms of finishing and polishing that are most commonly used in clinical practice.…”