Effect of Microwave Disinfection on Transverse Strength and Hardness of Acrylic Resin Denture Base Materials

Superficial and Inner Examination of a Microwave-Irradiated Dental Acrylic Resin and Its Metal–Polymer Interface

“…Due to the presence of metal in some of our test structures, the samples were immersed one by one in Pyrex beakers containing 150 mL of deionized water and introduced into the microwave oven. The wet microwave decontamination has been described by Dixon et al (1999) and eventually became a viable method used in future research (Neppelenbroek et al, 2003; Consani et al, 2006; Silva et al, 2006; Buergers et al, 2008; Consani et al, 2008; Mima et al, 2008; Ribeiro et al, 2008; Pinto de Campos et al, 2009; Ibrahem, 2010; Al-Saraj et al, 2011; Senna et al, 2011; Wagner & Pikpo, 2015). Thus, we could simultaneously investigate which of the two variable factors has a greater impact over the material alteration: the microwave power, or the irradiation time.…”

“…According to some authors, the roughness can increase after two high-power irradiation cycles (Sartori et al, 2006; Machado et al, 2009; Pinto de Campos et al, 2009; Ibrahem, 2010; Senna et al, 2011), promoting, together with porosity, the bacterial adherence and proliferation of microorganisms (Verran & Maryan, 1997; Vergani et al, 2011; Azam et al, 2015). In contrast, hardness is a very stable property of acrylic materials (including soft liners and hard relines) (Consani et al, 2008; Machado et al, 2009; Pinto de Campos et al, 2009; Ibrahem, 2010; Senna et al, 2011), usually being evaluated along with other parameters: roughness (Sartori et al, 2006; Pinto de Campos et al, 2009), transverse or flexural strength (Polyzois et al, 1995; Lai et al, 2004; Vergani et al, 2005; Consani et al, 2008; Ribeiro et al, 2008; Al-Saraj et al, 2011; Senna et al, 2011), impact strength (Consani et al, 2008; Senna et al, 2011), dimensional stability and deformation (Sartori et al, 2008; Al-Saraj et al, 2011; Senna et al, 2011; Wagner & Pikpo, 2015). Moreover, there are studies showing the increased hardness of heat-polymerized denture resins (Polyzois et al, 1995; Senna et al, 2011) and reline materials (Machado et al, 2005; Ribeiro et al, 2008; Machado et al, 2009) related to the microwave influence.…”

“…Moreover, there are studies showing the increased hardness of heat-polymerized denture resins (Polyzois et al, 1995; Senna et al, 2011) and reline materials (Machado et al, 2005; Ribeiro et al, 2008; Machado et al, 2009) related to the microwave influence. In the same train of ideas, the flexural strength of heat-cured resins is not detrimentally affected by microwave energy: it can remain unaltered (Polyzois et al, 1995; Consani et al, 2008; Ribeiro et al, 2008; Seó et al, 2008; Senna et al, 2011) or it can improve (Lai et al, 2004; Vergani et al, 2005; Al-Saraj et al, 2011). Although the linear dimensions of acrylic specimens are not modified by microwave energy according to some measurements (Polyzois et al, 1995; Consani et al, 2006), the dimensional stability of denture bases is affected by repeated or prolonged irradiation conditions (Polyzois et al, 1995; Pavan et al, 2005; Fleck et al, 2007; Seó et al, 2007; Machado et al, 2009; Ibrahem, 2010; Azam et al, 2015; Wagner & Pikpo, 2015).…”

Pengaruh Desinfeksi Energi Microwave Terhadap Kekuatan Transversal Resin Akrilik Polimerisasi Panas

“…15 Kekuatan transversal adalah salah satu sifat mekanik penting yang harus dimiliki basis gigitiruan untuk dapat bertahan agar tidak patah disebabkan beban pengunyahan yang besar. 16 Adapun tujuan penelitian ini adalah untuk mengetahui mengetahui pengaruh desinfeksi resin akrilik polimerisasi panas dengan energi microwave terhadap kekuatan transversal pada waktu yang berbeda.…”

“…Hal ini dapat dijelaskan dengan adanya peningkatan kekuatan transversal yang disebabkan oleh panas ketika dilakukan desinfeksi dengan energi microwave, telah membuat molekul monomer yang tidak bereaksi berdifusi ke permukaan dan menguap. 16 Menurut penelitian Suvarna dkk, energi microwave hanya berperan pada monomer, yaitu berkurangnya monomer sisa seiring dengan bertambahnya derajat polimerisasi. Didalam microwave, molekul monomer bergerak dengan medan elektromagnetik frekuensi tinggi, pergerakan molekul monomer tersebut disebabkan karena terjadinya panas internal.19 Kekuatan transversal resin akrilik dipengaruhi oleh berbagai faktor seperti berat molekul, ukuran partikel polimer, monomer sisa, komposisi plasticizer, jumlah ikatan silang pada rantai molekul, porositas, dan ketebalan basis gigitiruan.…”