Cerdika: Jurnal Ilmiah Indonesia, Juni 2021, 1 (6), 746-754 p-ISSN: 2774-6291 e-ISSN: 2774-6534 Available online at http://cerdika.publikasiindonesia.id/index.php/cerdika/index 10.36418/cerdika.v1i6.108 746 PENGARUH DESINFEKSI MODEL GIPSUM TIPE III MENGGUNAKAN SODIUM HYPOCHLORITE DAN MICROWAVE TERHADAP KEKUATAN KOMPRESI DAN KEKERASAN PERMUKAAN Sharmila Naidu A/P Iyal Naidu 1 and Eddy Dahar 2 Mahasiswa Fakultas Kedokteran Gigi Universitas Sumatera Utara Medan, Indonesia 1 Departemen Prostodonsia, Fakultas Kedokteran Gigi Sumatera Utara Medan, Indonesia 2 sharmilanaidu353@gmail.com 1 ; eddy_dahar@yahoo.com 2 Abstract Received: Revised : Accepted: 07-05-2021 23-06-2021 26-06-2021 Transmission of microorganism that come in contact with saliva and blood from dental impression process are transported from the patient oral cavity to the cast which leads to cross-contamination. The aim of this research was to determine the effect of disinfection of type III gypsum model using sodium hypochlorite and microwave on compressive strength and surface hardness. The plan of this research was laboratory experimental. The samples used was 60 samples of type III gypsum model, where 30 samples were prepared for compressive strength evaluation and 30 samples were prepared for surface hardness evaluation where each evaluation groups were divided into three groups: control group (10 samples without disinfection), 10 samples immersed in 0,5% of sodium hypochlorite for 10 minutes group and microwave irradiation at 550 watt for 10 minutes group. Test analysis used was ANOVA and (LSD) and the result showed that there was a significant difference on the effect of disinfection using 0,5% sodium hypochlorite for 10 minutes and microwave of 550 Watt for 10 minutes on the compressive strength and surface hardness of gypsum model type III (p=0,0001<0,05). Keywords: Type III gypsum model; sodium hypochlorite, microwave; compressive strength; surface hardness. Abstrak Saat prosedur pengambilan cetakan dilakukan, darah dan saliva akan menempel pada hasil cetakan dan hal ini memungkinkan terjadinya infeksi silang. Tujuan penelitian ini adalah untuk mengetahui pengaruh desinfeksi model gipsum tipe III menggunakan sodium hypochlorite dan microwave terhadap kekuatan kompresi dan kekerasan permukaan. Penelitian ini adalah penelitian eksperimental laboratoris dan total sampel pada penelitian ini adalah 60 sampel gipsum tipe III, yang mana 30 sampel digunakan untuk meneliti kekuatan kompresi dan 30 sampel digunakan untuk meneliti kekerasan permukaan yang mana dua kelompok penelitian ini dibagi