Effect of different initial finishes and Parylene coating thickness on the surface properties of coated PMMA

Abstract

Statement of the Problem. The colonization of micro-organisms on acrylic resin dentures may result in denture-induced stomatitis. No efficient coating has yet been proposed to address this issue. Purpose. The purpose of this in vitro study was to assess the effect of various initial surface finishes and different Parylene (P) coating thicknesses on the surface roughness (Ra) and surface free energy (SFE) of Parylene coated polymethyl methacrylate (PMMA). Material and Methods. One hundred and sixty PMMA specimens were produced and divided into 8 groups as follows: Group A: uncoated-1000grit finish; group Ap1: 10 μm P coated -1000grit finish; group B: uncoated -1200grit finish; group Bp: 10 μm P coated -1200grit finish; group C: uncoated2400grit finish; group Cp: 10 μm P coated -2400grit finish; group Ap2: 20 μm P coated -1000grit finish; group Ap3: 30 μm P coated -1000grit finish. The Ra of all specimens was measured with a noncontact profilometer. To calculate the SFE, the Owens-Wendt approach was applied after measuring the contact angles with a goniometer. The topography of the specimens was observed by scanning electron microscope. I am happy to report that the reviewers of manuscript #JPD-D-15-00013R3, entitled "The effect of different initial finishes and Parylene coating thickness on the surface properties of coated PMMA," have recommended that it be accepted for publication, pending your responses to the following final requests:Please review the edited manuscript to ensure that your meaning has not been inadvertently altered. Please address the comments.Answer: Thank you for the acceptance of our work for publication to the JPD. We are now submitting the final revision of the manuscript entitled "The effect of different initial finishes and Parylene coating thickness on the surface properties of coated PMMA". We have accepted all Track Changes and responded to the minor queries requested. The additions are marked in blue as per the instructions.We have uploaded the TIFF files of the images without labels as requested. The images uploaded are not in composite form, but individual images. We have only left the composite images in the manuscript file for ease of final proof editing by your team.

The effect of different chemical intra-oral prostheses cleansers on the surface properties of Parylene-coated PMMA

“…The results of this study clearly show that, regardless of the medium, Parylene coating led to a statistically significant reduction in mean surface roughness values of the PMMA samples tested. This is in agreement with previous studies 14,16) and demonstrates that the coating, at a microscopic-level, covers the pits and grooves, and results in a more uniform surface. The results also showed that Parylene provided some form of physical resistance against the chemical action of the cleansers.…”

“…Half of the groups were to be coated with 10 µm of Parylene-C 16) and the remainder left uncoated. A total of 60 PMMA samples were sent to Specialty Coatings Systems (SCS, Woking, UK) to be coated.…”

“…This was based on previous related studies [14][15][16] . All groups were randomly divided to be subject to immersion in either one of two commercially available cleanser solutions: Steradent (Reckitt Benckiser Healthcare, Hull,UK) an alkaline peroxide, or Poligrip (GlaxoSmithKline, Tokyo, Japan) which is marketed as a neutral peroxide with enzymes, or left in air acting as control.…”

“…The presence of MRSA is of growing concern as it could have implications in regard to cross infection and involvement in systemic infection 8,11,12) . Various modifications or coatings of polymethyl methacrylate (PMMA) have been used with the aim to reduce biofilm formation 3,[13][14][15][16] . Parylene, is the commercial name of poly(p-xylylene) which represents a variety of polymers which can be deposited as a vapour on a substrate.…”

“…It is transparent, highly resistant to the action of organic and inorganic solvents as well as to friction 14,15) . Recent studies have been evaluating the use of Parylene as a coating for intraoral prostheses, and the results have shown a decrease in surface roughness of PMMA accompanied by an increase in SFE 16) , a resistance to mechanical wear 14) , as well as a decrease in the growth of Candida albicans 15) . Instructions for the care of removable prostheses may involve the use of mechanical means, such as brushing with or without a cream, and chemical means in the form of immersion in various solutions 1,4,19) .…”