Extensive efforts were undertaken to develop suitable biomaterials for tissue engineering (TE) applications. To facilitate clinical approval processes and ensure the success of TE applications, bioinspired concepts are currently focused on. Working on bone tissue engineering, we describe in the present study a method for biofunctionalization of collagen/hydroxyapatite composites with BMP-2 mimetic peptides. This approach is expected to be fundamentally transferable to other tissue engineering fields. A modified BMP-2 mimetic peptide containing a negatively charged poly-glutamic acid residue (E7 BMP-2 peptide) was used to bind positively charged hydroxyapatite (HA) particles by electrostatic attraction. Binding efficiency was biochemically detected to be on average 85% compared to 30% of BMP-2 peptide without E7 residue. By quartz crystal microbalance (QCM) analysis, we could demonstrate the time-dependent dissociation of the BMP-2 mimetic peptides and the stable binding of the E7 BMP-2 peptides on HA-coated quartz crystals. As shown by immunofluorescence staining, alkaline phosphatase expression is similar to that detected in jaw periosteal cells (JPCs) stimulated with the whole BMP-2 protein. Mineralization potential of JPCs in the presence of BMP-2 mimetic peptides was also shown to be at least similar or significantly higher when low peptide concentrations were used, as compared to JPCs cultured in the presence of recombinant BMP-2 controls. In the following, collagen/hydroxyapatite composite materials were prepared. By proliferation analysis, we detected a decrease in cell viability with increasing HA ratios. Therefore, we chose a collagen/hydroxyapatite ratio of 1:2, similar to the natural composition of bone. The following inclusion of E7 BMP-2 peptides within the composite material resulted in significantly elevated long-term JPC proliferation under osteogenic conditions. We conclude that our advanced approach for fast and cost-effective scaffold preparation and biofunctionalization is suitable for improved and prolonged JPC proliferation. Further studies should prove the functionality of composite scaffolds in vivo.

Objectives: Publications on stamp techniques for placing resin-based composite (RBC) restorations consist mainly of case studies. Furthermore, comparative studies are rare and no longer relevant to the materials tested today. Thus, two general techniques were investigated in this study. Materials and methods: Standardized occlusion class I cavities were prepared in twenty-eight extracted caries-free wisdom teeth with unimpaired occlusal surfaces and restored with the RBC material Grandio^®. Light curing of the final layer was performed either after removal of the stamp isolated with PTFE tape or by leaving a stamp made of transparent polysiloxane in place. CEREC scans of the RBC restorations placed (follow-up) were superimposed on scans of the unimpaired occlusal surface (baseline) and quantitatively analyzed with the software OraCheck with regard to volume change and gain or loss of layer thickness in six sectional planes. Results: Assessing the excess material, there was no difference (p = 0.31) between the silicone technique (0.26 mm ± 0.02) and the PTFE technique (0.22 mm ± 0.02 mm). Nevertheless, the loss of tooth substance was significantly greater (p < 0.001) with the silicone technique (−0.29 mm ± 0.02 mm) than with the PTFE technique (−0.15 mm ± 0.02 mm). Conclusions: With the PTFE stamp technique, less healthy tooth structure was removed during the finishing procedure and the stamp was more dimensionally stable. Clinical relevance: The study shows the advantages and disadvantages of the investigated stamp techniques and helps the practitioner to choose an appropriate technique.

Objectives The autofluorescence of dental hard tissues has been known for over 100 years. Thus, manufacturers add fluorophores to dental restorative materials to improve the esthetic properties of these materials. So far, there has been no study evaluating the ability of these fluorophores to reproduce the autofluorescence of dental hard tissues. Materials and Methods A total of 240 different color shades representing 17 different brands of fluorescent light‐curing RBC and CAD/CAM restorative materials were analyzed with a monochromator‐based microplate reader. Additionally, combined enamel‐dentin specimens (n = 11) were analyzed as “gold standard”. The total fluorescence (TF) and the physiologically relevant luminous efficiency function adjusted total fluorescence (TF_a) were determined. The differences between the brands and the enamel‐dentin specimens were further evaluated and visualized as contour plots. Results Merely the TF_a of the brands CERASMART™, Filtek Supreme XTE™, KZR‐CAD HD 2, and LuxaCam composite were not significantly different to the enamel‐dentin specimens. The analysis of the contour plots revealed that even these four materials showed a fluorescence excess for the excitation wavelengths below about 400 nm and a deficit above this wavelength. Conclusion None of the materials analyzed in this study were able to reproduce the natural fluorescence spectrum of the enamel‐dentin specimens. Clinical Significance Unlike the statements and images of blue fluorescent materials in the manufacturers' brochures, none of the materials examined here is fully capable of reproducing the natural autofluorescence of teeth.