Dental materials have to meet high standards regarding mechanical strength and handling properties. There is however only a limited amount of research that has been devoted to natural formation of hydroxyapatite (HA) in contact with the materials. The objective of the current investigation was to study the surface reactions occurring in human salvia on a novel dental cement. Ceramir Crown & Bridge, a bioceramic luting agent intended for permanent cementation of conventional oral prosthetics, was evaluated by immersing discs made from the cement in human saliva and phosphate buffered saline (PBS) for seven days, after which they were dried and analyzed. The analytical methods used in order to verify HA formation on the surface were grazing incidence X-ray diffraction (GI-XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). All results showed that HA was formed on the surfaces of samples stored in saliva as well as on samples stored in PBS. The possibility of a dental luting cement to promote natural formation of HA at the tooth interface increases the stability and durability of the system and could help prevent secondary caries. 1. Introduction Publications describing dental materials that promote restoring of a damaged tooth based on natural formation of hydroxyapatite (HA) are limited, that is, functional remineralizing/bioactive dental materials. All clinically used dental materials have to meet high standards with respect to handling and mechanical properties. However, the known bioactive biomaterials generally have low mechanical strength or are difficult to handle and mould, for example, bioglasses [1–3]. Attempts have been made to develop materials that promote dental remineralization of the tooth by releasing Ca2+ and ions, but so far no truly bioactive dental material has been made commercially available [4]. One material that is considered to have remineralizing properties and the necessary mechanical properties to function as a dental material is calcium aluminate (CA) [5, 6]. The main mechanism behind bioactive properties of a material has been connected to its negatively charged surface and its release of calcium, phosphate, and hydroxyl groups. These properties can even promote HA formation on the surface of the material when stored in water [7]. The mechanisms behind the HA surface layer formed have been discussed in detail elsewhere [8–10]. There are a number of materials that display bioactive properties, normally aimed as bone void fillers, for example, bioglasses, sintered hydroxyl apatites,
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