The aim of the present work was to prepare a series of novel restorative giomers and investigate the morphology, the physico-chemical properties (residual monomer, fluoride release), and the cytotoxicity of the new materials. The experimental giomers were prepared as light-cured pastes by blending different resin matrices comprising aromatic/aliphatic/urethane (di) methacrylates, with hybrid fillers containing pre-reacted glasses (PRGs), a radiopaque glass, and nano fluorhydroxyapatite. Polyalkenoic acids based on acrylic acid/itaconic acid/N-acryloyl -L-leucine modified or not with methacrylic groups, together with a superficially active glass, were used to prepare the PRGs. The fluoride ion release of the experimental giomers was investigated within a period of 60 days of storage in bidistilled water while using a fluoride ion selective electrode. Beautifil II commercial product was used as a reference. Cell cytotoxicity tests were done in vitro, in accordance with ISO 10993-122012 proceedings. Human dermal fibroblasts and umbilical endothelial vein cultures were used. The values that were obtained for cumulative fluoride release for all experimental giomers were higher than for the Beautifil II product, being more than twice the ones that were obtained for the commercial product after 60 days of storage in bidistilled water. The experimental biomaterials showed similar and/or better results when compared to the commercial one; this effect was maintained in all tested conditions.

Dental light-curing giomers were developed to combine the favourable properties of diacrylic resin composites (DRCs) and glass-ionomer cements (GICs) in a single material and to eliminate their inherent drawbacks. Giomers are characterized by their aesthetic appearance, high mechanical properties, adhesion to dental tissues as well as fluoride release and recharge abilities. The qualities of the giomers are greatly influenced by the level of conversion of the component resins. Infrared spectroscopy is one of the most largely used techniques for the determination of the degree of conversion in resin-based dental materials. However different results were obtained due to the performances of the used methods. The present work presents the determination of conversion degree in a series of dental copolymers and their corresponding giomers using transmission Fourier transform infrared spectroscopy (FTIR) and an attenuated total reflection technique (ATR) technique, respectively, the main aim being the study of the influence of the materials composition and of the light curing modes upon the achieved conversion in the cured giomers. Beautifil II commercial giomer was used as a control. A halogen lamp and a diode-blue LED lamp were used for the curing of the materials. The results showed that the composition of the resins greatly influenced the conversion. The highest conversions (up to 79%) were obtained in the case of the experimental giomers which contained the experimental Bis-GMA urethane analogue, followed by the Beautifil II giomer (61%) and experimental giomers based on commercial Bis-GMA (up to 50%), respectively. The resins light-cured by using the diode-blue LED lamp presented slightly higher conversions than the resins cured by halogen lamp. The study demonstrates the possibility to evaluate easily and reproducibly the conversion in light-curing composite materials with complex chemical composition and structure, particularly in the case of giomers by using the ATR technique.

The aim of the present study is to measure the optical properties of dental materials, color and translucency, as well as their radiopacity using digital images. To do this, an original software application implementing two functions has been developed. Determining the radiopacity amount of certain areas of the materials is achieved by interpolating the values of ten aluminum plates used as reference. The study of this property is achieved by interpreting the statistical results and graphs displayed. The translucency value was calculated as the difference of the CIELab color system values for two digital images representing the same material on white and black background, respectively. In order to evaluate the color changes of the biomaterials, the samples were immersed in coffee, wine and orange juice. The application has been tested on several experimental materials based on bioceramics, dental composites and giomers, and the results are similar to the ones obtained using other evaluation methods.

The aim of this work was to reduce microleakage in giomer restorations by using innovative materials in both adhesive systems and light-cured dental giomer. Two adhesive systems with different primers were investigated. The innovative compounds in the primers were acrylic acid (AA)/itaconic acid (IA) copolymer modified with methacrylic groups and AA/IA/N-acryloyl-L-leucine copolymer grafted with methacrylic groups. In addition, the investigated new giomer G contains a pre-reacted glass based on the latter copolymer. The commercial Beautifil II giomer and the FL-Bond II adhesive system were used for comparison. Microleakage was evaluated by determining the scores and percentages of dye penetration lengths after thermocycling of a series of light-cured dental giomer restorations performed on 42 premolars extracted for orthodontic reasons. A lower microleakage value was recorded for the adhesive system containing the AA/IA/N-acryloyl-L-leucine copolymer grafted with methacrylic groups than for the commercial adhesive, which was in substantial agreement with SEM and AFM investigations. In this case, remarkable dentin sealing and a strong adhesion at the giomer restoration�tooth interface was observed, and the innovative adhesive was proven to be promising for dental applications.

In this study we evaluate a new computer software developed for determining tooth color parameters obtained from digital images taken in a general practice working conditions. In order to evaluate the accuracy of the program, we used as samples dental shade tabs. The tabs were measured using a dental spectrophotometer, and then photographed and measured using our program (Toodent). L, a, b values of the CIE Lab color space were obtained. The results were also automatically expressed in dental shade tab code. The results analysis was made by comparing the L, a, b values obtained by the program, with spectrophotometer ones taken from the same shade tab. A statistical indicator was created in order to evaluate the accuracy of the program. Further evaluation of the program shall be made, in order to be used in routine clinical color selection.