Original article Effect of different disinfectants on the microhardness and roughness of acrylic resins for ocular prosthesis Ama ´ lia Moreno, Marcelo C. Goiato, Daniela M. dos Santos, Marcela F. Haddad, Aldie ´ ris A. Pesqueira and Lisiane C. Bannwart Department of Dental Materials and Prosthodontics, UNESP – Univ Estadual Paulista, Faculty of Dentistry of Arac ¸atuba, University of the State of Sa ˜o Paulo, Sa ˜ o Paulo, Brazil Gerodontology 2012; doi: 10.1111/j.1741-2358.2012.00642.x Effect of different disinfectants on the microhardness and roughness of acrylic resins for ocular prosthesis Background: Ocular prosthesis materials should have specific properties for their indication and dura- bility; therefore, it is important to investigate their physical behaviour when affected by several disinfec- tants. Objectives: This study evaluated the influence of different disinfecting solutions on the microhardness and surface roughness of acrylic resins for ocular prosthesis. Materials and Methods: Fifty samples simulating ocular prostheses were fabricated with N1 resin and colourless resin and divided (n = 10) according to the disinfectant used: neutral soap, Opti-free, Efferdent, 1% hypochlorite (HYC) and 4% chlorhexidine (CHX). Samples were stored in saline solution at 37°C and disinfected during 120 days. Both microhardness and roughness were investigated before, after 60 days and 120 days of disinfection and storage. Microhardness was measured using a microhardner and the roughness with a roughness device. Results: N1 resin showed lower microhardness when compared with colourless resin (p < 0.05). HYC and CHX groups exhibited the highest change of microhardness and roughness values (p < 0.05). An increase in roughness and reduction in microhardness of ocular acrylic resins were observed after both periods of disinfection and storage (p < 0.05). Conclusion: Both disinfection/storage periods affected the microhardness and roughness values of the samples. Keywords: disinfection, artificial eye, physical properties, acrylic resins, maxillofacial prosthesis. Accepted 25 September 2011 Introduction Ocular prosthesis is a modality of maxillofacial prosthesis 1–3 and aims to fill out the anophthalmic cavity, restoring and beautifying the compromised patient¢s face 4–6 . It also contributes to the psycho- logical and social development of the user and provides increased quality of life 7,8 . Currently, many elderly people are users of ocular prosthesis, and they report high rate of prosthesis fall during handling, mainly due to prosthesis shape. As a result, the acrylic resin can acquire an irregular surface, with small imperfections such as marks and scratches that are uncomfortable for the user. Thus, these materials must have suitable properties to use and to maintain the prosthesis 9–11 . To create ocular prostheses, an association between artificial sclera and colourless resins is used 11–13 . The sclera resin presents white pigments to reproduce the natural appearance of the patient¢s sclera and has a thickness ranging from 2 to 10 mm. The colourless resin is used to cover the blood vessels characteri- sation and the artificial iris with 1- to 3.5-mm thickness 12,13 . The surface microhardness of acrylic resins is directly related to the longevity of ocular prosthesis in which the greater the microhardness, the higher its resistance to abrasive wear 10,13,14 . Depending on the surface roughness characteristic, microorgan- ism accumulation may occur, which is hardly re- moved by mechanical and chemical means 11,15,16 . Thus, not only the resistance to abrasive wear but Ó 2012 The Gerodontology Society and John Wiley & Sons A/S 1