MATERIALE PLASTICE https://revmaterialeplastice.ro https://doi.org/10.37358/Mat.Plast.1964 Mater. Plast., 58 (4), 2021, 197-209 197 https://doi.org/10.37358/MP.21.4.5545 Comparison of the Effects of Sugar-free Solutions, Cola, Mouthwash on the Surface Hardness and Roughness of Temporary Crown Materials NURAN YANIKOGLU 1 ORCID ID: 0000-0001-7677-1248, ZEYNEP YESIL DUYMUS 1 , ORCID ID: 0000-0002-9767-0080 SEBAHAT FINDIK AYDINER 2* ORCID ID:0000-0003-3476-5135 1 Department of Prosthodontics, Faculty of Dentistry, Atatürk University, Erzurum, Turkey 2 Dentist, Ministry of Health Yıldırım Beyazıt University Yenimahalle Training and Research Hospital, Yenimahalle/Ankara, Turkey Abstract: The aim of this study is to investigate the effect of polishing with different solutions on the surface roughness and hardness of two different polymethylmethacrylate temporary restoration materials. In the study, two different temporary crown materials prepared in the CAD / CAM system and prepared by the traditional method were used to test a total of 224 pieces of 10 mm diameter and 2 mm thickness. After the surface roughness and micro hardness values were measured, samples were randomly divided into seven groups among themselves; After waiting 24 h, 1 and 3 weeks, values were measured again. Data were evaluated using 3-way analysis of variance (ANOVA) and Tukey HSD test. The temporary restorative materials' surface hardness and roughnesses are important to be able to stay in oral cavity without any changes. And it is also important to determine which of the materials (prepared by temporary conventional materiels or by the CAD/CAM) are less effected by the liquids in oral cavity. Keywords: polymethylmethacrylate, temporary dental restorations, surface properties, mouthwashes, CAD-CAM, sugar acids 1.Introduction A temporary restoration must be made immediately after tooth preparation to protect the cut tooth from thermal bacterial and chemical effects. These restorations must have the strength to withstand masticatory forces, have good marginal fit and esthetics, and be able to protect pulp and periodontium. Temporary restorative materials have low fracture resistance. Consequently, the use of restorations with improved physical properties is recommended, especially in cases of long-body fixed partial prosthesis, in the treatment of Temporomandibular Joint (TMJ) diseases requiring long-term treatment, in cases where the vertical dimension of the occlusion needs to be changed, in bruxism cases and in areas with excessive occlusal loads [1-4]. Materials with different chemical structures and improved physical properties are available for use in restorations. Polymethylmethacrylate, polymethylmethacrylate bis- acryl based, and micro-filled resins are used in the clinic as temporary restoration materials. Different studies have shown that polymethylmethacrylates have lower wear resistance and better esthetic properties than polymethylmethacrylate bis-acryl and micro-filled resins [5, 6]. The oral environment can be very corrosive for dental materials. Depending on his nutritional habits, the contents of the nutrients that an individual consumes and his saliva can react with the materials used in restorations, disrupting their structure and affecting their mechanical and physical properties. Other studies have determined that the resin matrix of dental composites exposed to organic acids and different nutrients softens and that these chemicals cause dissolution in the resin and filler interface [7, 8]. All kinds of foods and beverages in the oral environment can cause tooth discoloration, decay and wear depending on exposure time and the quality of oral hygiene. They can also create changes in the *email: rona13_rona@hotmail.com