Three-dimensional (3D) porous scaffolds for supporting cell adhesion and growth play a vital role in tissue engineering applications. In the present study, three different collagen-based 3D sponges were functionalized by apatite coating. The sponges were coated with apatite on their outer and inner surfaces while retaining their interconnecting pores. To achieve this, we employed a vacuum degassing system in our plasma- and precursor-assisted biomimetic process using a supersaturated calcium phosphate solution. The resulting apatite-coated sponges (mineralized sponges) showed better cell adhesion properties in vitro for osteoblast-like MC3T3-E1 cells compared to that of uncoated sponges. The three mineralized sponges were implanted in the subcutaneous tissue of rats. Upon histological evaluation after 10 days, the mineralized sponges showed cell in-growth rates that were approximately 4-fold greater than those of the untreated sponges without any notable inflammatory reactions. As these sponges are composed of clinically approved collagen-based frameworks and possess a 3D porous structure with a mineralized surface appropriate for cell adhesion and internalization, further in vitro and in vivo studies should be conducted regarding tissue engineering applications.

Surface pre-reacted glass-ionomer (S-PRG) fillers release antibacterial borate and fluoride ions. We fabricated nanoscale S-PRG fillers (S-PRG nanofillers) for antibacterial coating of tooth surfaces and assessed the antibacterial effects of this coating in vitro. In addition, we creating a canine model of periodontitis to evaluate the effectiveness of S-PRG nanofiller application on tooth roots and improvement of periodontal parameters.Methods: Human dentin blocks were coated with S-PRG nanofiller (average particle size: 0.48 μm) and then characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDX), and ionreleasing test. Antibacterial effects of dentin blocks coated with S-PRG nanofiller were examined using bacterial strains, Streptococcus mutans and Actinomyces naeslundii. Next, we created an experimental model of periodontitis in furcation of premolars of beagle dogs. Then, S-PRG nanofiller coating was applied onto exposed tooth root surfaces. Periodontal parameters, gingival index (GI), bleeding on probing (BOP), probing pocket depth (PPD), and clinical attachment level (CAL), were measured from baseline until 4 weeks. In addition, bone healing was radiographically and histologically examined. Results: SEM and EDX revealed that S-PRG nanofillers uniformly covered the dentin surface after coating. Dentin blocks coated with S-PRG nanofiller showed ion-releasing property, bacterial growth inhibition, and sterilization effects. In the experimental periodontitis model, S-PRG nanofiller coating significantly reduced clinical inflammatory parameters, such as GI (P < 0.01) and BOP (P < 0.05), compared to uncoated samples. In addition, PPD and CAL significantly decreased by S-PRG nanofiller coating (2 weeks: P < 0.05; 3 and 4 weeks: P < 0.01), suggesting the improvement of periodontitis. Micro-CT and histology revealed that bone healing of furcation defects was enhanced by S-PRG nanofiller coating. Conclusion: S-PRG nanofiller coating provides antibacterial effects to tooth surfaces and improves clinical parameters of periodontitis.

Recombinant human collagen peptide, developed based on human collagen type I, contains an arginyl‐glycyl‐aspartic acid (RGD)‐rich motif to enhance cell behavior and is anticipated as a xeno‐free polymer material for use in tissue engineering. We fabricated granules containing recombinant human collagen peptide (RCP) applied with beta‐tricalcium phosphate fine particles (RCP/β‐TCP) as bone filling scaffold material and assessed the bone forming ability of RCP/β‐TCP. Recombinant peptide was thermal crosslinked and freeze‐dried to prepare RCP. An aqueous dispersion of β‐TCP fine particles was added to RCP to obtain RCP/β‐TCP. Subsequently, RCP/β‐TCP were characterized using scanning electron microscopy (SEM), energy dispersive X‐ray spectrometry (EDX), and cell culture assessments. Furthermore, RCP/β‐TCP were implanted into rat cranial bone defects for radiographic and histological evaluations. In SEM and EDX analyses of RCP/β‐TCP, β‐TCP particles dose‐dependently covered the surface of RCP. Cell culture tests showed that RCP/β‐TCP remarkably promoted proliferation and mRNA expression of various genes, such as integrin β1 and osteogenic markers, of osteoblastic MC3T3‐E1 cells. Histomorphometric assessment at 4 weeks showed that RCP/β‐TCP significantly promoted new skull bone formation compared to RCP (p < 0.05) and control (no application) (p < 0.01). Accordingly, these findings suggest RCP/β‐TCP possess bone forming capability and would be beneficial for bone tissue engineering therapy.

Antimicrobial surfactants contained in mouthrinse have excellent efficacy, but are not retained on the tooth surface (are rinsed away) due to their low water resistance and thus do not exhibit sustained antibacterial activity. We have developed a new coating method using graphene oxide (GO) that retains the surfactant on the tooth surface even after rinsing with water, thus providing a sustained antibacterial effect. Ultra-thin films of GO and an antimicrobial agent were prepared by (1) applying GO to the substrate surface, drying, and thoroughly rinsing with water to remove excess GO to form an ultrathin film (almost a monolayer, transparent) on the substrate surface, then (2) applying antimicrobial cationic surface active agents (CSAAs) on the GO film to form a composite coating film (GO/CSAA). GO/CSAA formation was verified by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and ζ-potential and contact angle measurements. GO/CSAA was effective at inhibiting the growth of oral pathogens for up to 7 days of storage in water, and antibacterial activity was recovered by reapplication of the CSAA. Antibacterial GO/CSAA films were also formed on a tooth substrate. The results suggest that GO/CSAA coatings are effective in preventing oral infections.

Background and objectives:In the treatment of severe periodontal destruction, there is a strong demand for advanced scaffolds that can regenerate periodontal tissues with adequate quality and quantity. Recently, we developed a plasma-and precursorassisted biomimetic process by which a porous collagen scaffold (CS) could be coated with low-crystalline apatite. The apatite-coated collagen scaffold (Ap-CS) promotes cellular ingrowth within the scaffold compared to CS in rat subcutaneous tissue. In the present study, the osteogenic activity of Ap-CS was characterized by cell culture and rat skull augmentation tests. In addition, the periodontal tissue reconstruction with Ap-CS in a beagle dog was compared to that with CS. Methods:The plasma-and precursor-assisted biomimetic process was applied to CS to obtain Ap-CS with a low-crystalline apatite coating. The effects of apatite coating on the scaffold characteristics (i.e., surface morphology, water absorption, Ca release, protein adsorption, and enzymatic degradation resistance) were assessed.Cyto-compatibility and the osteogenic properties of Ap-CS and CS were assessed in vitro using preosteoblastic MC3T3-E1 cells. In addition, we performed in vivo studies to evaluate bone augmentation and periodontal tissue reconstruction with Ap-CS and CS in a rat skull and canine furcation lesion, respectively.Results: As previously reported, the plasma-and precursor-assisted biomimetic process generated a low-crystalline apatite layer with a nanoporous structure that uniformly covered the Ap-CS surface. Ap-CS showed significantly higher water absorption, Ca release, lysozyme adsorption, and collagenase resistance than CS. Cell culture experiments revealed that Ap-CS was superior to CS in promoting the osteoblastic differentiation of MC3T3-E1 cells while suppressing their proliferation.Additionally, Ap-CS significantly promoted (compared to CS) the augmentation of the rat skull bone and showed the potential to regenerate alveolar bone in a dog furcation defect.How to cite this article: Kanemoto Y, Miyaji H, Nishida E, et al.Periodontal tissue engineering using an apatite/collagen scaffold obtained by a plasma-and precursor-assisted biomimetic process.