Original Research Article International Journal of Oral Health Dentistry. January – March 2016;2(1):1-14 1 Is Polymethly Methacrylate Stain Friendly when used in Extra-Oral Maxillofacial Prosthesis…? Rucha Kashyap Gulati Sr. Lecturer, Peoples College of Dental Sciences and Research Center, Bhanpur, Bhopal, Madhya Pradesh, India E-mail: dr.rk4u@gmail.com Abstract Background & Objectives: The present study was conducted to find out a stain material that can retain its color in acrylic for a long period, by assessing its chemical interaction with the parent material and to evaluate the color stability of commonly used acrylic resin-stain combinations after exposure to weathering. Method: This experiment was carried out on PMMA-stain combination specimens. The acrylic blocks were divided into two categories. Scrapings from first category were subjected to spectroscopy to determine the interaction of the four PMMA-stain combinations at molecular level. And scrapings from second category were tested with spectrophotometer after being subjected to weathering. The comparison between the graphs obtained was made using absorbance variance. Results: Glass paint, acrylic emulsion, and organic dye produce changes which are evident in the spectrograph. Fabric paint does not produce much change in the spectrograph. Before and after subjecting the acrylic resin-fabric paint combination to natural weathering, suggest that the colorant is most stable. On the contrary organic dye and glass paint are least stable of all the four stains. Conclusion: The addition of colors to PMMA for staining definitely produces changes in the structure of the PMMA at the molecular level. The addition of inorganic group stains produce change but which are insignificant, whereas the addition of organic group stains produce changes at the molecular level which are significant. Inorganic coloring agent (fabric paint) was the most color stable over time whereas the organic colorants (glass paint, acrylic emulsion, organic dye) were the least color stable. Keywords: Chemical interaction, color stability, PMMA-stain combination, weathering. Access this article online Quick Response Code: Website: www.innovativepublication.com DOI: 10.5958/2395-499X.2016.00001.0 Introduction Prosthetic reconstruction is indicated in patients with facial defects that are the result of congenital anomalies, trauma, resection after cancer, or some combination of these occurrences. The Primary Purpose of a maxillofacial prosthesis is therefore to restore the patient’s appearance and protect the resection site, allowing improvement in self-esteem to help the patient lead as normal a life as possible[1]. Though silicon prosthesis has an good reproduction detail[2,3], acrylic resin has been employed for all types of maxillofacial defects, owing to its easy method of fabrication, ease to stain and economic advantage[4]. The wearing time for maxillofacial prosthesis averages from 3 months to 1 year. The limited service of facial prosthesis is a result of short term durability and its color instability. Deterioration is mainly caused by environmental exposure to ultraviolet (UV) light, air pollution, changes in humidity and temperature[3]. Acrylic resin is stained using two type of pigments - Organic and Inorganic. Both when added to acrylic resin, may or may not react with the polymer and alter the structure of polymer[5]. Hence the need for this study was – 1. To evaluate the effect of stains on polymethyl methacrylate at the molecular level, by using Ultraviolet/visible spectroscopy. 2. To determine the color stability of stains using colorimeter in polymethyl methacrylate when exposed to weathering. 3. To find out a stain material that can retain its color in acrylic for a long period, by assessing its chemical interaction with the parent material. 4. To evaluate the color stability of commonly used acrylic resin - stain combinations after exposure to weathering. Materials and methods Stainless steel dies measuring 2 cm x 2 cm in length and breadth, 3 mm in thickness were fabricated. These dies were then invested in dental plaster (type II). Once the plaster was set the dies were removed creating a mold space. Clear heat cure acrylic resin (DPI) was selected for the study. Stains used were Fabric paint, Glass paint, Acrylic emulsion, and Organic dye[6]. The stains were added to the monomer. Acrylic powder and stained monomer was mixed in a ratio of 3:1 by volume, packed into the mold space in dough stage and subjected to heat curing. The acrylic blocks made were divided into 5 groups: Group I - No Stain (Control),