## 1 Introduction  
Despite the new techniques of taking impressions, in the form of intraoral scanners and various types of silicone materials, alginates are still one of the most commonly used impression materials [1]. This is the result of their properties, including ease of use, hydrophilicity and therefore good contact with the tissues to have the impression taken from, and low pressure needed to be exerted on delicate soft tissues [2, 3]. Slight pressure on soft tissues during impression taking is especially important when making removable dentures, skeletal dentures, or removable orthodontic devices. It is also significant that alginate is a biodeived material and may easily decompose after use, in contrast to silicone materials [4]. Alginate powder, after mixing with the appropriate amount of water, forms an elastic sol, which, when working, quickly becomes a gel, reacting with calcium ions present in the formulation [5; 6]. There are also studies on making alginate material available in the form of two separate gels, which can be mixed by extrusion from the cartridge, similar to silicone sealants or two-component adhesives. Unfortunately, alginate materials have a number of disadvantages, including low tear resistance and release of water from the material during storage, causing shrinkage of the setting material and changes in dimensions [7; 8]. Therefore, casting gypsum models from alginate impressions should be performed as soon as possible [9; 10; 11]. However, before making a plaster model, it is necessary to disinfect the impression, as it is a source of cross-infections due to the initial contact with the patient's tissues and saliva [9; 12; 13; 14]. The disinfection of the impression can be carried out using two methods: immersing the impression ray with setting material in a solution of a disinfectant or spraying the surface of the impression with a suitable preparation. It can be performed by contacting the impression with 0.15% chlorhexidine water solution [15] or placing it in a closed bag for a period of 10-15 min, the time necessary for proper disinfection [16; 17]. Other disinfectants for alginate can be alcohol or aldehyde solution [18; 19]. However, special attention should be paid to alcohol-based disinfectants, as they cause strong water absorption and changes in the dimensions of the impression during the disinfection process itself [9; 20]. On the other hand, storing impressions in aqueous solutions of disinfectants causes water absorption through the alginate and changes in its dimensions (expansion) [20]. Furthermore, the disinfection process itself is a labour-intensive step, which requires appropriately trained personnel to ensure that no damage or distortions to the material are caused. Therefore, it would be desirable to create an alginate material formulation with inherent antibacterial properties. There are reports that describe the addition of various types of chemical substances that have antibacterial properties: ceramic negative ions [9], silver [21], 0.2% silver nitrate, 0.2% chlorohexidine solution [22], chitosan [23], and silver nanoparticles [24; 25]. However, a large part of this research focusses on the addition of a germicidal substance to the water-alginate mixture, which is clinically undesirable because it complicates the preparation of the alginate sol. A much better solution is to add the disinfectant directly to the powder, thus modifying the formulation, while leaving the sol preparation procedure unchanged. Some of the popular impression disinfectants cannot be used directly in the impression material due to their very high toxicity (aldehydes, sodium hypochlorite, iodine compounds, etc.) [26; 27]. One possible substance that exhibits bactericidal properties is AlphaSan RC 2000, a commercial zirconium phosphate-based ceramic ion exchange resin. There are a number of papers in the literature describing the addition of silver to alginate materials. However, their use requires adding silver in the form of a solution [22; 24] that is not desired by the end user.