Background: Oral hygiene is essential for maintaining residual dentition of partial denture wearers. The dental material should positively affect the oral environment. Fluoride-releasing dental materials help to inhibit microbial colonization and formation of plaque as well as to initiate the remineralization process in the early cavity area. Aim: To evaluate fluoride ion release and recharge capacity, sorption, and solubility of polymethyl methacrylate (PMMA) dental resin modified with bioactive glass addition. Materials and methods: Two bioactive glass materials (5 wt% Kavitan, 10 wt% Kavitan, and 10 wt% Fritex) and pure 10 wt% NaF were added to dental acrylic resin. After polymerization of the modified resins, the release levels of fluoride anions were measured based on color complex formation by using a spectrophotometer after 7, 14, 28, and 35 days of storage in distilled water at 37 °C. Subsequently, specimens were brushed with a fluoride-containing tooth paste on each side for 30 s, and the fluoride recharge and release potential was investigated after 1, 7, and 14 days. Sorption and solubility after 7 days of storage in distilled water was also investigated. Results: The acrylic resins with addition of 10% bioactive glass materials released fluoride ions for over 4 weeks (from 0.14 to 2.27 µg/cm2). The amount of fluoride ions released from the PMMA resin with addition of 10 wt% Fritex glass was higher than that from the resin with addition of 10 wt% Kavitan. The acrylic resin containing 10 wt% NaF released a high amount of ions over a period of 1 week (1.58 µg/cm2), but the amount of released ions decreased rapidly after 14 days of storage. For specimens containing 5 wt% Kavitan glass, the ion-releasing capacity also lasted only for 14 days. Fluoride ion rechargeable properties were observed for the PMMA resin modified with addition of 10 wt% Fritex glass. The ion release levels after recharge ranged from 0.32 to 0.48 µg/cm2. Sorption values ranged from 10.23 μm/mm3 for unmodified PMMA resin to 12.11 μm/mm3 for specimens modified with 10 wt% Kavitan glass. No significant differences were found regarding solubility levels after 7 days. Conclusions: The addition of 10 wt% Fritex and 10 wt% Kavitan bioactive glass materials to heat-cured acrylic resin may improve its material properties, with bioactive fluoride ion release ability lasting for over 4 weeks. The resin modified with 10 wt% Fritex glass could absorb fluoride ions from the toothpaste solution and then effectively release them. Addition of fluoride releasing fillers have a small effect on sorption and solubility increase of the modified PMMA resin. Clinical significance: The addition of bioactive glass may be promising in the development of the novel bioactive heat-cured denture base resin.

The study focused on the comparison between mechanical and computerized registration methods used by the two selected kinematic facebows. The material consisted of 35 women aged 18 to 35, studied using the Gerber Dynamic Facebow and the computerized ARCUSdigma II axiograph. To compare the devices the condylar path inclination (CPI) was recorded according to the Camper's line, enabling the acquisition of easily comparable values based on which the devices were objectively and subjectively analyzed. Statistics was performed for the obtained data. The study showed that the values for the CPI registrated by the ARCUSdigma II are significantly higher than those obtained by using the Gerber Dynamic Facebow. The significant difference in the records of the CPI is most likely a result of the differences in the registration techniques assumptions. ARCUSdigma II provides the user with more diagnostic options than Gerber Dynamic Facebow. Mechanical facebow handling has a higher risk of hand-measuring errors in tracing procedure. Due to high discrepancy of achieved results from different systems the authors recommend to use articulator compatible with facebow whose measurement has been done.

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: Acrylic resins are the most commonly used materials in prosthetics and orthodontics until now. They have a well-documented history of use as biomaterials in the manufacture of different types of dental appliances. The objective of this study was to describe the properties of acrylic resins and the processing methods used for these materials in dentistry. The review depicts the most important achievements in this area, indicating that the resin technology evolved in different directions. The mechanical and biological properties of acrylic resins were improved by the addition of mineral or natural fibers, and/or fillers including nanofillers, as well as by poly(methyl methacrylate) surface modification. The presence of residual monomer was reduced as a result of postpolymerization activity. New types of acrylic resins were developed for processing Computer-Aided Design/Computer-Aided Manufacturing systems and three-dimensional printing.

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