Recently, our group showed that additional supplementation of Trolox™ (vitamin E analogue) can significantly enhance the antimicrobial photodynamic effect of the photosensitizer Indocyanine green (ICG). Up to now, the combined effect has not yet been investigated on Enterococcus faecalis in dental root canals. In the present in vitro study, eighty human root canals were inoculated with E. faecalis and subsequently subjected to antimicrobial Photodynamic Therapy (aPDT) using ICG (250, 500, 1000 µg/mL) and near-infrared laser light (NIR, 808 nm, 100 Jcm⁻²). Trolox™ at concentrations of 6 mM was additionally applied. As a positive control, irrigation with 3% NaOCl was used. After aPDT, root canals were manually enlarged and the collected dentin debris was subjected to microbial culture analysis. Bacterial invasion into the dentinal tubules was verified for a distance of 300 µm. aPDT caused significant suppression of E. faecalis up to a maximum of 2.9 log counts (ICG 250 µg/mL). Additional application of Trolox^TM resulted in increased antibacterial activity for aPDT with ICG 500 µg/mL. The efficiency of aPDT was comparable to NaOCl-irrigation inside the dentinal tubules. In conclusion, ICG significantly suppressed E. faecalis. Additional application of Trolox^TM showed only minor enhancement. Future studies should also address the effects of Trolox^TM on other photodynamic systems.

(1) Background: In the oral environment, sound enamel and dental restorative materials are immediately covered by a pellicle layer, which enables bacteria to attach. For the development of new materials with repellent surface functions, information on the formation and maturation of salivary pellicles is crucial. Therefore, the present in situ study aimed to investigate the proteomic profile of salivary pellicles formed on different dental composites. (2) Methods: Light-cured composite and bovine enamel samples (controls) were exposed to the oral cavity for 30, 90, and 120 min. All samples were subjected to optical and mechanical profilometry, as well as SEM surface evaluation. Acquired pellicles and unstimulated whole saliva samples were analyzed by SELDI–TOF–MS. The significance was determined by the generalized estimation equation and the post-hoc bonferroni adjustment. (3) Results: SEM revealed the formation of homogeneous pellicles on all test and control surfaces. Profilometry showed that composite surfaces tend to be of higher roughness compared to enamel. SELDI–TOF–MS detected up to 102 different proteins in the saliva samples and up to 46 proteins in the pellicle. Significant differences among 14 pellicle proteins were found between the composite materials and the controls. (4) Conclusions: Pellicle formation was material- and time-dependent. Proteins differed among the composites and to the control.

Background: Material-dependent parameters have an important impact on the efficiency of light polymerization. The present in vitro study aimed to investigate the influence of the increment thickness and shade of nano- and nanohybrid resin composites on the transmission of curing light. Methods: Three contemporary resin composites were evaluated: Tetric EvoCeram^® (TEC); Venus Diamond^® (VD); and Filtek Supreme XTE^® (FS XTE). Light transmission (LT) was recorded in accordance with the sample thickness (0.5 to 2.7 mm) and the shade. Polymerized samples were irradiated for 10 s each using the high-power LED curing light Celalux 2 (1900 mW/cm²). LT was simultaneously recorded using the MARC Patient Simulator (MARC-PS). Results: LT was strongly influenced by the composite layer thickness. For 0.5 mm-thick samples, a mean power density of 735 mW/cm² was recorded at the bottom side. For the 2.7 mm samples, a mean power density of 107 mW/cm² was measured. Only LT was markedly reduced in the case of darker shades. From A1 to A4, LT decreased by 39.3% for FS XTE and 50.8% for TEC. Dentin shades of FS XTE and TEC (A2, A4) showed the lowest LT. Conclusions: The thickness and shade of resin composite increments strongly influences the transmission of curing light. More precise information about these parameters should be included in the manufacture manual.

(1) Background: The in vitro study aimed to investigate mechanical characteristics of resin composites and their suitability in direct restauration of endodontically treated teeth (ETT). (2) Methods: 38 endodontically treated premolars with occlusal access cavities were directly restored using the following resin composites and adhesives: Tetric Evo Ceram^® + Syntac classic^® (n = 10), Venus Diamond^® + iBond Total-Etch^® (n = 10), Grandio^® + Solobond M^® (n = 9), Estelite^® Sigma Quick + Bond Force^® (n = 9). After thermocycling, the elastic modulus, shear-bond-strength, fracture load (Fmax) and fracture mode distribution were evaluated. Statistical analysis: one-way ANOVA, t-test, Kruskal–Wallis test; p < 0.05. (3) Results: Grandio^® showed the highest E-modulus (15,857.9 MPa) which was significant to Venus Diamond^® (13,058.83 MPa), Tetric Evo Ceram^® (8636.0 MPa) and Estelite^® Sigma Quick (7004.58 MPa). The highest shear-bond-strength was observed for Solobond M^® (17.28 MPa), followed by iBond^® (16.61 MPa), Syntac classic^® (16.41 MPa) and Bond Force^® (8.37 MPa, p < 0.05). The highest fracture load (Fmax) was estimated for ETT restored with Venus Diamond^® (1106.83 N), followed by Estelite^® Sigma Quick (1030.1 N), Tetric Evo Ceram^® (1029 N) and Grandio^® (921 N). Fracture-mode distribution did not show any significant differences. (4) Conclusions: The observed resin composites and adhesives show reliable mechanical characteristics and seem to be suitable for direct restoration of endodontically treated teeth.

Background/Objectives: The effect of fusidic acid on oral bacteria, especially on Gram- negative periodontopathogenic species, has not yet been investigated. This in vitro study aimed to analyze the antibacterial effect of fusidic acid alone and as an active component in electrospun poly(L-lactide-co-D/L-lactide) fiber fleeces. Methods: Minimal inhibitory concentrations (MIC) of fusidic acid and metronidazole (control) were determined for various oral bacteria. Eluates were collected from electrospun poly(L-lactide-co-D/L-lactide) fiber fleeces loaded with 10 and 20 wt% fusidic acid over a period of 28 d. Antibacterial activity was analyzed by means of a microdilution assay. Cytotoxicity was observed toward human gingival fibroblasts (HGFs). Results: All tested Gram-positive and Gram-negative oral bacteria were susceptible to fusidic acid. The lowest MIC was observed for Porphyromonas gingivalis (MIC < 0.062 µg/mL). Compared to the antibacterial activity of metronidazole, that of Porphyromonas gingivalis was suppressed by significant lower fusidic acid concentrations (p < 0.01). The eluates obtained from electrospun poly(L-lactide-co-D/L-lactide) fiber fleeces inhibited the growth of P. gingivalis, S. aureus, A. viscosus, and A. neslundii over a course of 28 days. The largest inhibition zones were detected for Porphyromonas gingivalis in case of the 20 wt% concentrations. The eluates were not cytotoxic toward HGFs. Conclusions: It was shown that fusidic acid has significant antibacterial potential. The results of the present investigation suggest that fusidic acid alone or delivered by electrospun fiber fleeces might be attractive for controlling oral pathogenic bacteria.