The Effects of Maleic Anhydride Terpolymer and its Ester Derivatives on Tensile Bond Strength Between the Acrylic Resin and Resilient Lining Material O. Murat Dogan, 1 Giray Bolayır, 1 Ali Boztug ˘, 2 Mehmet Turgut, 1 H. Bayram Zengin 2 1 Department of Prosthodontics, Faculty of Dentistry, Cumhuriyet University, Sivas, Turkey 2 Department of Chemistry, Cumhuriyet University, Sivas, Turkey Received 22 July 2006; accepted 15 November 2006 DOI 10.1002/app.25846 Published online in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: The present study investigated the effects on the bonding between the denture base acrylic resin and the soft silicon based lining material of maleic anhydride- styrene-vinyl acetate (MA-St-VA) terpolymer and some of its ester derivatives. These ester derivatives were n-propyl- maleate-styrene-vinyl acetate (n-PrMA-St-VA), n-buthylma- leate-styrene-vinyl acetate (n-BuMA-St-VA) and n-ben- zylmaleate-styrene-vinyl acetate (n-BzMA-St-VA). Fourier Transform infrared spectroscopy method was used to deter- mine interactions between terpolymers with the acrylic resin and soft lining material. The tensile bond strength of all the groups was compared and the obtained differences were statistically significant (P < 0.05). The highest value was found for the samples lined with n-BuMA-St-VA (2.11 6 0.21 MPa) and the samples lined with n-BzMA-St-VA had the lowest bond strength (0.3 6 0.12 MPa). Ó 2007 Wiley Periodi- cals, Inc. J Appl Polym Sci 104: 1338–1341, 2007 Key words: poly (methyl methacrylate); lining material; interfacial adhesion; maleic anhydride INTRODUCTION Acrylic resin is commonly used as a denture base material dentistry. In some cases, for example, if patients are not able to tolerate the hard denture base, the soft lining materials are used in the inner surface of denture base. The resilience of these mate- rials can absorb the occurring active forces during chewing and they disperse these forces from the alveolar ridge to wider surface area. Hence, the use of denture by patients becomes easy. 1,2 Soft denture liners have several problems associated with their use, such as loss of softness, colonization by Candida albicans, porosity, debonding of liner from base, etc. Among these problems, adhesion failure between silicone resilient denture lining materials and the denture base is commonly encountered in clinical practice. 3,4 In general, the bonding between the acrylic resins and silicon based soft liner materials possess poor adhesion characteristics. Several publications have focused on the factors that can affect bonding, including the nature and direction of debonding force, and liner thickness, the nature adhesive agent, and variations in the structure of the acrylic resin denture base. 5–7 Many researchers have measured the bond strength between the soft liner and the acrylic resin materials by using peel, shear and ten- sile bond tests. It has been shown that the measured bond strength of soft liners to acrylic is dependent on the type of testing method used. The tensile bond strength test is a good method of investigating the bond strength of soft lining materials. 8–10 Many studies have been performed on the use of reactive interfacial agents to improve interfacial adhesion. The reactive interfacial agents have spe- cific functional groups. However, research on the detailed understanding of the enhancement of inter- facial properties resulting from reactive compatibili- zation is very limited. 11–13 Maleic functional compounds have wide ranging applications as additives to promote adhesion and compatibility. 14,15 Lee and Char have shown that the interfacial adhesion between polyamide and polysty- rene was enhanced by the addition of thin layers of maleic anhydride-styrene random copolymer. 16 On the other hand, we investigated the effects on the bonding between the denture base acrylic resin and the soft silicon based lining material of maleic anhy- dride-styrene-vinyl acetate (MA-St-VA) terpolymer and some of its ester derivatives. EXPERIMENTAL Materials MA-St-VA terpolymer and some of its ester deriva- tives used in this study were synthesized and char- Correspondence to: A. Boztug ˘ (aboztug@cumhuriyet. edu.tr). Journal of Applied Polymer Science, Vol. 104, 1338–1341 (2007) V V C 2007 Wiley Periodicals, Inc.