(1) secondary caries was successfully produced in rats; (2) there was a correlation between the modified Keyes scoring method and micro-CT in the evaluation of the secondary caries; (3) the adhesive containing DMADDM significantly reduced both LD and ML (according to micro-CT), and also lowered the scores (based on the modified Keyes scoring method). This suggests that the novel DMADDM adhesive could perform an anticaries function in vivo via the secondary caries animal model which was also developed and testified in research. Secondary caries is one of the major reasons leading to the failure of caries restoration treatment. As a solution, anticaries adhesives perform well in biofilm inhibition in vitro. However, the lack of secondary caries animal models limits the evaluation of anticaries adhesives in vivo. Secondary caries is one of the main reasons for restoration failure with a heavy economic burden [Sakaguchi, 2005;Kasraei et al., 2017]. While many factors facilitate the development of secondary caries, oral bacteria and acid production are the initiators of dental caries [Mjor Keywords Antibacterial material · Bonding system · Dimethylaminododecyl methacrylate · Keyes animal model · Micro-CT · Tooth restoration AbstractWe investigated the anticaries properties of an adhesive containing dimethylaminododecyl methacrylate (DMADDM) in vivo via a secondary caries animal model. Cavities were prepared in the maxillary first molars of Wistar rats. DMADDM-containing adhesives were applied on one side and commercial adhesives on the opposite side as a control. After a 3-week feeding period to induce secondary caries, the molars were harvested for the evaluation of the secondary caries. Lesion depth (LD) and mineral loss (ML) were measured via a micro-CT method, and a modified Keyes scoring method yielded scores for the caries lesions. Statistical analysis was divided into 2 parts: a correlation analysis between 2 evaluations with one-way ANOVA and a least-significant differences (LSD) test, and an evaluation of anticaries adhesives with a paired samples t test. The results showed that:

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Osteoporosis greatly impairs in vivo implant osseointegration because of poor osteogenesis in osteoporotic conditions and the low bioactivity of implants, such as titanium-based biomaterials. Various surface engineering strategies, including unstable physical absorption or complex chemical conjugations, have been developed to biofunctionalize titanium implants and improve interfacial osseointegration. However, very few of them took into consideration the clinically challenging osteoporotic condition, as well as dual-functionalization of the implants for improvement of both osteoblast adhesion and osteogenesis. In this work, we combined two mussel-inspired bioactive peptides (i.e., with cell adhesive or osteogenic sequences) for one-step dual-functionalization of Ti screws via a facile self-organized multivalent coordinative interaction. In vitro study indicated that the biomimetic dual-functional coating could efficiently improve the osteogenesis of osteoporosis-derived mesenchymal stem cells despite of their impaired bone metabolism. Moreover, under osteoporotic in vivo condition, the dual-functional peptide coating on Ti screws could also give rise to significant enhancement of interfacial osteogenesis, newly formed bone condition, osseointegration, as well as implant mechanical stability. This is probably due to the integrin-targeted cell adhesive and osteogenic motifs on the modified Ti screws, which recovered the regular bone metabolism equilibrium between osteogenesis and osteoclastogenesis in an osteoporotic condition. We anticipate that the highly biomimetic peptides and one-step dual-functionalized strategy would provide a facile and effective means for improving the clinical outcome of Ti-based implants in patients with a disturbed bone metabolism.

Upon the osteoporotic condition, sluggish osteogenesis, excessive bone resorption, and chronic inflammation make the osseointegration of bioinert titanium (Ti) implants with surrounding bone tissues difficult, often lead to prosthesis loosening, bone collapse, and implant failure. In this study, we firstly designed clickable mussel-inspired peptides (DOPA-N3) and grafted them onto the surfaces of Ti materials through robust catechol-TiO 2 coordinative interactions. Then, two dibenzylcyclooctyne (DBCO)-capped bioactive peptides RGD and BMP-2 bioactive domain (BMP-2) were clicked onto the DOPA-N3-coated Ti material surfaces via bio-orthogonal reaction. We characterized the surface morphology and biocompatibility of the Ti substrates and optimized the osteogenic capacity of Ti surfaces through adjusting the ideal ratios of BMP-2/RGD at 3:1. In vitro, the dual-functionalized Ti substrates exhibited excellent promotion on adhesion and osteogenesis of mesenchymal stem cells (MSCs), and conspicuous immunopolarization-regulation to shift macrophages to alternative (M2) phenotypes and inhibit inflammation, as well as enhancement of osseointegration and mechanical stability in osteoporotic rats. In summary, our biomimetic surface modification strategy by bio-orthogonal reaction provided a convenient and feasible method to resolve the bioinertia and clinical complications of Ti-based implants, which was conducive to the long-term success of Ti implants, especially in the osteoporotic or inflammatory conditions.