The present study investigates the effect of an oxidized nanocrystalline diamond (O-NCD) coating functionalized with bone morphogenetic protein 7 (BMP-7) on human osteoblast maturation and extracellular matrix mineralization in vitro and on new bone formation in vivo. The chemical structure and the morphology of the NCD coating and the adhesion, thickness and morphology of the superimposed BMP-7 layer have also been assessed. The material analysis proved synthesis of a conformal diamond coating with a fine nanostructured morphology on the Ti6Al4V samples. The homogeneous nanostructured layer of BMP-7 on the NCD coating created by a physisorption method was confirmed by AFM. The osteogenic maturation of hFOB 1.19 cells in vitro was only slightly enhanced by the O-NCD coating alone without any increase in the mineralization of the matrix. Functionalization of the coating with BMP-7 resulted in more pronounced cell osteogenic maturation and increased extracellular matrix mineralization. Similar results were obtained in vivo from micro-CT and histological analyses of rabbit distal femurs with screws implanted for 4 or 12 weeks. While the O-NCD-coated implants alone promoted greater thickness of newly-formed bone in direct contact with the implant surface than the bare material, a further increase was induced by BMP-7. It can be therefore concluded that O-NCD coating functionalized with BMP-7 is a promising surface modification of metallic bone implants in order to improve their osseointegration.

Department of Pathology Charles University 3rd Faculty of Medicine Ruska 2411 100 00 Prague 10 Czech Republic

Faculty of Electrical Engineering Czech Technical University Prague Technicka 2 166 27 Prague 6 Czech Republic

Institute of Anatomy Charles University 1st Faculty of Medicine U Nemocnice 3 128 00 Prague 2 Czech Republic

Institute of Dental Medicine Charles University 1st Faculty of Medicine U Nemocnice 2 1280 00 Prague 2 Czech Republic

Institute of Physics Czech Academy of Sciences Cukrovarnicka 10 162 00 Prague 6 Czech Republic

Institute of Physiology of the Czech Academy of Sciences Videnska 1083 142 20 Prague 4 Czech Republic

Zobrazit více v PubMed

Katti KS. Biomaterials in total joint replacement. Colloids Surf. B Biointerfaces. 2004;39:133–142. doi: 10.1016/j.colsurfb.2003.12.002. PubMed DOI

Geetha M, Singh AK, Asokamani R, Gogia AK. Ti based biomaterials, the ultimate choice for orthopaedic implants – A review. Prog. Mater. Sci. 2009;54:397–425. doi: 10.1016/j.pmatsci.2008.06.004. DOI

Navarro M, Michiardi A, Castano O, Planell JA. Biomaterials in orthopaedics. J. R. Soc. Interface. 2008;5:1137–1158. doi: 10.1098/rsif.2008.0151. PubMed DOI PMC

Hanawa T. Metal ion release from metal implants. Mater. Sci. Eng. C-Mater. Biol. Appl. 2004;24:745–752. doi: 10.1016/j.msec.2004.08.018. DOI

Jinno T, Goldberg VM, Davy D, Stevenson S. Osseointegration of surface-blasted implants made of titanium alloy and cobalt-chromium alloy in a rabbit intramedullary model. J. Biomed. Mater. Res. 1998;42:20–29. doi: 10.1002/(sici)1097-4636(199810)42:1<20::aid-jbm4>3.0.co;2-q. PubMed DOI

Evans JT, et al. How long does a hip replacement last? A systematic review and meta-analysis of case series and national registry reports with more than 15 years of follow-up. Lancet. 2019;393:647–654. doi: 10.1016/S0140-6736(18)31665-9. PubMed DOI PMC

Quinn J, McFadden R, Chan C-W, Carson L. Titanium for orthopedic applications: An overview of surface modification to improve biocompatibility and prevent bacterial biofilm formation. iScience. 2020;23:101745. doi: 10.1016/j.isci.2020.101745. PubMed DOI PMC

Bral A, Mommaerts MY. In vivo biofunctionalization of titanium patient-specific implants with nano hydroxyapatite and other nano calcium phosphate coatings: A systematic review. J. Cranio-Maxillofac. Surg. 2016;44:400–412. doi: 10.1016/j.jcms.2015.12.004. PubMed DOI

Arcos D, Vallet-Regi M. Substituted hydroxyapatite coatings of bone implants. J. Mater. Chem. B. 2020;8:1781–1800. doi: 10.1039/c9tb02710f. PubMed DOI PMC

Mohammadi H, Muhamad N, Sulong A, Ahmadipour M. Recent advances on biofunctionalization of metallic substrate using ceramic coating: How far are we from clinically stable implant? J. Taiwan Inst. Chem. Eng. 2021;118:254–270. doi: 10.1016/j.jtice.2021.01.013. DOI

Doubkova M, Nemcakova I, Jirka I, Brezina V, Bacakova L. Silicalite-1 layers as a biocompatible nano- and micro-structured coating: An in vitro study on MG-63 cells. Materials. 2019;12:3583. doi: 10.3390/ma12213583. PubMed DOI PMC

Kopova I, Kronek J, Bacakova L, Fencl J. A cytotoxicity and wear analysis of trapeziometacarpal total joint replacement implant consisting of DLC-coated Co-Cr-Mo alloy with the use of titanium gradient interlayer. Diamond Relat. Mater. 2019 doi: 10.1016/j.diamond.2019.107456. DOI

Orrit-Prat J, et al. Bactericidal silver-doped DLC coatings obtained by pulsed filtered cathodic arc co-deposition. Surf. Coat. Technol. 2021 doi: 10.1016/j.surfcoat.2021.126977. DOI

Kopova I, Bacakova L, Lavrentiev V, Vacik J. Growth and potential damage of human bone-derived cells on fresh and aged fullerene C-60 films. Int. J. Mol. Sci. 2013;14:9182–9204. doi: 10.3390/ijms14059182. PubMed DOI PMC

Kopova I, Lavrentiev V, Vacik J, Bacakova L. Growth and potential damage of human bone-derived cells cultured on fresh and aged C60/Ti films. PLoS ONE. 2015;10:e0123680. doi: 10.1371/journal.pone.0123680. PubMed DOI PMC

Thukkaram M, et al. Investigation of Ag/a-C: H nanocomposite coatings on titanium for orthopedic applications. ACS Appl. Mater. Interfaces. 2020;12:23655–23666. doi: 10.1021/acsami.9b23237. PubMed DOI

Szunerits S, Nebel CE, Hamers RJ. Surface functionalization and biological applications of CVD diamond. MRS Bull. 2014;39:517–524. doi: 10.1557/mrs.2014.99. DOI

Bacakova L, et al. Bone cells in cultures on nanocarbon-based materials for potential bone tissue engineering: A review. Phys. Status Solidi A. 2014;211:2688–2702. doi: 10.1002/pssa.201431402. DOI

Erdemir A, Martin JM. Superior wear resistance of diamond and DLC coatings. Curr. Opin. Solid State Mater. Sci. 2018;22:243–254. doi: 10.1016/j.cossms.2018.11.003. DOI

Papo MJ, Catledge SA, Vohra YK. Mechanical wear behavior of nanocrystalline and multilayer diamond coatings on temporomandibular joint implants. J. Mater. Sci. - Mater. Med. 2004;15:773–777. doi: 10.1023/B:JMSM.0000032817.05997.d2. PubMed DOI

Budil J, et al. Anti-adhesive properties of nanocrystalline diamond films against Escherichia coli bacterium: Influence of surface termination and cultivation medium. Diam. Relat. Mater. 2018;83:87–93. doi: 10.1016/j.diamond.2018.02.001. DOI

Jakubowski W, Bartosz G, Niedzielski P, Szymanski W, Walkowiak B. Nanocrystalline diamond surface is resistant to bacterial colonization. Diam. Relat. Mater. 2004;13:1761–1763. doi: 10.1016/j.diamond.2004.03.003. DOI

Medina O, et al. Bactericide and bacterial anti-adhesive properties of the nanocrystalline diamond surface. Diam. Relat. Mater. 2012;22:77–81. doi: 10.1016/j.diamond.2011.12.022. DOI

Rifai A, et al. Engineering the interface: Nanodiamond coating on 3d-printed titanium promotes mammalian cell growth and inhibits Staphylococcus aureus colonization. ACS Appl. Mater. Interfaces. 2019;11:24588–24597. doi: 10.1021/acsami.9b07064. PubMed DOI

Amaral M, et al. Nanocrystalline diamond: In vitro biocompatibility assessment by MG63 and human bone marrow cells cultures. J. Biomed. Mater. Res. Part A. 2008;87A:91–99. doi: 10.1002/jbm.a.31742. PubMed DOI

Ivanova L, et al. Nanocrystalline diamond containing hydrogels and coatings for acceleration of osteogenesis. Diam. Relat. Mater. 2011;20:165–169. doi: 10.1016/j.diamond.2010.11.020. DOI

Kalbacova M, Rezek B, Baresova V, Wolf-Brandstetter C, Kromka A. Nanoscale topography of nanocrystalline diamonds promotes differentiation of osteoblasts. Acta Biomater. 2009;5:3076–3085. doi: 10.1016/j.actbio.2009.04.020. PubMed DOI

Liskova J, et al. Osteogenic cell differentiation on H-terminated and O-terminated nanocrystalline diamond films. Int. J. Nanomed. 2015;10:869–884. doi: 10.2147/ijn.s73628. PubMed DOI PMC

Steinerova M, et al. Human osteoblast-like SAOS-2 cells on submicron-scale fibers coated with nanocrystalline diamond films. Mater. Sci. Eng. C-Mater. Biol. Appl. 2021 doi: 10.1016/j.msec.2020.111792. PubMed DOI

Kloss FR, et al. The role of oxygen termination of nanocrystalline diamond on immobilisation of BMP-2 and subsequent bone formation. Biomaterials. 2008;29:2433–2442. doi: 10.1016/j.biomaterials.2008.01.036. PubMed DOI

Jaatinen JJP, et al. Early bone growth on the surface of titanium implants in rat femur is enhanced by an amorphous diamond coating. Acta Orthop. 2011;82:499–503. doi: 10.3109/17453674.2011.579522. PubMed DOI PMC

Metzler P, et al. Nano-crystalline diamond-coated titanium dental implants - A histomorphometric study in adult domestic pigs. J. Craniomaxillofac. Surg. 2013;41:532–538. doi: 10.1016/j.jcms.2012.11.020. PubMed DOI

Rupprecht S, et al. The bone-metal interface of defect and press-fit ingrowth of microwave plasma-chemical vapor deposition implants in the rabbit model. Clin. Oral Implants Res. 2005;16:98–104. doi: 10.1111/j.1600-0501.2004.01079.x. PubMed DOI

Smeets R, et al. Impact of dental implant surface modifications on osseointegration. Biomed. Res. Int. 2016;2016:6285620. doi: 10.1155/2016/6285620. PubMed DOI PMC

Cecchi S, Bennet SJ, Arora M. Bone morphogenetic protein-7: Review of signalling and efficacy in fracture healing. J. Orthopaed. Transl. 2015;4:28–34. doi: 10.1016/j.jot.2015.08.001. PubMed DOI PMC

Maliakal JC, Asahina I, Hauschka PV, Sampath TK. Osteogenic protein-1 (BMP-7) inhibits cell proliferation and stimulates the expression of markers characteristic of osteoblast phenotype in rat osteosarcoma (17/2.8) cells. Growth Factors. 1994;11:227–234. doi: 10.3109/08977199409046920. PubMed DOI

Sampath TK, et al. Recombinant human osteogenic protein-1 (hOP-1) induces new bone formation in vivo with a specific activity comparable with natural bovine osteogenic protein and stimulates osteoblast proliferation and differentiation in vitro. J. Biol. Chem. 1992;267:20352–20362. doi: 10.1016/S0021-9258(19)88709-4. PubMed DOI

Zhang F, et al. The optimal dose of recombinant human osteogenic protein-1 enhances differentiation of mouse osteoblast-like cells: An in vitro study. Arch. Oral Biol. 2012;57:460–468. doi: 10.1016/j.archoralbio.2011.10.008. PubMed DOI

Al-Jarsha M, et al. Engineered coatings for titanium implants to present ultralow doses of BMP-7. ACS Biomater. Sci. Eng. 2018;4:1812–1819. doi: 10.1021/acsbiomaterials.7b01037. PubMed DOI PMC

Lee H, Min SK, Song Y, Park YH, Park JB. Bone morphogenetic protein-7 upregulates genes associated with osteoblast differentiation, including collagen I, Sp7 and IBSP in gingiva-derived stem cells. Exp. Ther. Med. 2019;18:2867–2876. doi: 10.3892/etm.2019.7904. PubMed DOI PMC

Sun HL, et al. Osteogenic differentiation of human amniotic fluid-derived stem cells induced by bone morphogenetic protein-7 and enhanced by nanofibrous scaffolds. Biomaterials. 2010;31:1133–1139. doi: 10.1016/j.biomaterials.2009.10.030. PubMed DOI PMC

Chen FG, et al. Bone morphogenetic protein 7-transduced human dermal-derived fibroblast cells differentiate into osteoblasts and form bone in vivo. Connect. Tissue Res. 2018;59:223–232. doi: 10.1080/03008207.2017.1353085. PubMed DOI

Chen FG, et al. Bone morphogenetic protein 7 enhances the osteogenic differentiation of human dermal-derived CD105(+) fibroblast cells through the Smad and MAPK pathways. Int. J. Mol. Med. 2019;43:37–46. doi: 10.3892/ijmm.2018.3938. PubMed DOI PMC

Leknes KN, et al. Alveolar ridge augmentation using implants coated with recombinant human bone morphogenetic protein-7 (rhBMP-7/rhOP-1): Radiographic observations. J. Clin. Periodontol. 2008;35:914–919. doi: 10.1111/j.1600-051X.2008.01308.x. PubMed DOI

Susin C, et al. Alveolar ridge augmentation using implants coated with recombinant human bone morphogenetic protein-7 (rhBMP-7/rhOP-1): Histological observations. J. Clin. Periodontol. 2010;37:574–581. doi: 10.1111/j.1600-051X.2010.01554.x. PubMed DOI

Wang Q, et al. Application of combined porous tantalum scaffolds loaded with bone morphogenetic protein 7 to repair of osteochondral defect in rabbits. Int. Orthop. 2018;42:1437–1448. doi: 10.1007/s00264-018-3800-7. PubMed DOI

Schierano G, et al. Role of rhBMP-7, fibronectin, and type I collagen in dental implant osseointegration process: An initial pilot study on minipig animals. Materials. 2021 doi: 10.3390/ma14092185. PubMed DOI PMC

Terheyden H, Jepsen S, Moller B, Tucker MM, Rueger DC. Sinus floor augmentation with simultaneous placement of dental implants using a combination of deproteinized bone xenografts and recombinant human osteogenic protein-1 - A histometric study in miniature pigs. Clin. Oral Implant Res. 1999;10:510–521. doi: 10.1034/j.1600-0501.1999.100609.x. PubMed DOI

Cloutier M, et al. Calvarial bone wound healing: A comparison between carbide and diamond drills, Er:YAG and Femtosecond lasers with or without BMP-7. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endodontol. 2010;110:720–728. doi: 10.1016/j.tripleo.2010.04.003. PubMed DOI

Girard B, et al. Microtomographic analysis of healing of femtosecond laser bone calvarial wounds compared to mechanical instruments in mice with and without application of BMP-7. Lasers Surg. Med. 2007;39:458–467. doi: 10.1002/lsm.20493. PubMed DOI

Hoellig M, et al. Mesenchymal stem cells from reaming material possess high osteogenic potential and react sensitively to bone morphogenetic protein 7. J. Appl. Biomater. Funct. Mater. 2017;15:E54–E62. doi: 10.5301/jabfm.5000333. PubMed DOI

Westhauser F, et al. Bone formation of human mesenchymal stem cells harvested from reaming debris is stimulated by low-dose bone morphogenetic protein-7 application in vivo. J. Orthop. 2016;13:404–408. doi: 10.1016/j.jor.2016.08.002. PubMed DOI PMC

Desmyter S, Goubau Y, Benahmed N, De Wever A, Verdonk R. The role of bone morphogenetic protein-7 (osteogenic protein-1 (r)) in the treatment of tibial fracture non-unions - An overview of the use in Belgium. Acta Orthop. Belg. 2008;74:534–537. PubMed

Singh R, Bleibleh S, Kanakaris NK, Giannoudis PV. Upper limb non-unions treated with BMP-7: Efficacy and clinical results. Injury-Int. J. Care Injured. 2016;47:S33–S39. doi: 10.1016/s0020-1383(16)30837-3. PubMed DOI

Kozak H, et al. Chemical modifications and stability of diamond nanoparticles resolved by infrared spectroscopy and Kelvin force microscopy. J. Nanopart. Res. 2013;15:1568. doi: 10.1007/s11051-013-1568-7. DOI

Rezek B, Michalíková L, Ukraintsev E, Kromka A, Kalbacova M. Micro-pattern guided adhesion of osteoblasts on diamond surfaces. Sensors. 2009;9:3549–3562. doi: 10.3390/s90503549. PubMed DOI PMC

Rezek B, et al. Adsorption of fetal bovine serum on H/O-terminated diamond studied by atomic force microscopy. Diam. Relat. Mater. 2009;18:918–922. doi: 10.1016/j.diamond.2009.02.009. DOI

Domonkos M, et al. Diamond nucleation and growth on horizontally and vertically aligned Si substrates at low pressure in a linear antenna microwave plasma system. Diam. Relat. Mater. 2018;82:41–49. doi: 10.1016/j.diamond.2017.12.018. DOI

Ukraintsev E, Rezek B, Kromka A, Broz A, Kalbacova M. Long-term adsorption of fetal bovine serum on H/O-terminated diamond studied in situ by atomic force microscopy. Phys. Status Solidi (B) 2009;246:2832–2835. doi: 10.1002/pssb.200982257. DOI

Harris SA, Enger RJ, Riggs BL, Spelsberg TC. Development and characterization of a conditionally immortalized human fetal osteoblastic cell-line. J. Bone Miner. Res. 1995;10:178–186. doi: 10.1002/jbmr.5650100203. PubMed DOI

Subramaniam M, et al. Further characterization of human fetal osteoblastic hFOB 1.19 and hFOB/ER alpha cells: Bone formation in vivo and karyotype analysis using multicolor fluorescent in situ hybridization. J. Cell. Biochem. 2002;87:9–15. doi: 10.1002/jcb.10259. PubMed DOI

Bohuslavova R, et al. HIF-1 alpha is required for development of the sympathetic nervous system. Proc. Natl. Acad. Sci. U.S.A. 2019;116:13414–13423. doi: 10.1073/pnas.1903510116. PubMed DOI PMC

Kubikova T, et al. Comparison of ground sections, paraffin sections and micro-CT imaging of bone from the epiphysis of the porcine femur for morphometric evaluation. Ann. Anat.-Anat. Anzeiger. 2018;220:85–96. doi: 10.1016/j.aanat.2018.07.004. PubMed DOI

Wohl AP, Troilo H, Collins RF, Baldock C, Sengle G. Extracellular regulation of bone morphogenetic protein activity by the microfibril component fibrillin-1. J. Biol. Chem. 2016;291:12732–12746. doi: 10.1074/jbc.M115.704734. PubMed DOI PMC

Kozak H, et al. Infrared absorption spectroscopy of albumin binding with amine-containing plasma polymer coatings on nanoporous diamond surfaces. Langmuir. 2019;35:13844–13852. doi: 10.1021/acs.langmuir.9b02327. PubMed DOI

Ohyashiki T, et al. Oxygen radical-induced inhibition of alkaline phosphatase activity in reconstituted membranes. Arch. Biochem. Biophys. 1994;313(2):310–317. doi: 10.1006/abbi.1994.1393. PubMed DOI

Lee DH, et al. Effects of hydrogen peroxide (H2O2) on alkaline phosphatase activity and matrix mineralization of odontoblast and osteoblast cell lines. Cell Biol. Toxicol. 2006;22(1):39–46. doi: 10.1007/s10565-006-0018-z. PubMed DOI

Hoshino T, et al. Low serum alkaline phosphatase activity associated with severe Wilson's disease. Is the breakdown of alkaline phosphatase molecules caused by reactive oxygen species? Clin. Chim. Acta. 1995;238(1):91–100. doi: 10.1016/0009-8981(95)06073-m. PubMed DOI

Farley JR, Hall SL, Tanner MA, Wergedal JE. Specific activity of skeletal alkaline phosphatase in human osteoblast-line cells regulated by phosphate, phosphate esters, and phosphate analogs and release of alkaline phosphatase activity inversely regulated by calcium. J. Bone Miner. Res. 1994;9(4):497–508. doi: 10.1002/jbmr.5650090409. PubMed DOI

Ball V. Activity of alkaline phosphatase adsorbed and grafted on "polydopamine" films. J. Colloid Interface Sci. 2014;429:1–7. doi: 10.1016/j.jcis.2014.05.002. PubMed DOI

Phimphilai M, Zhao Z, Boules H, Roca H, Franceschi RT. BMP signaling is required for RUNX2-dependent induction of the osteoblast phenotype. J. Bone Miner. Res. 2006;21:637–646. doi: 10.1359/jbmr.060109. PubMed DOI PMC

Carvalho MS, Cabral JMS, da Silva CL, Vashishth D. Bone matrix non-collagenous proteins in tissue engineering: Creating new bone by mimicking the extracellular matrix. Polymers Basel. 2021 doi: 10.3390/polym13071095. PubMed DOI PMC

Kram V, et al. Biglycan in the skeleton. J. Histochem. Cytochem. 2020;68:747–762. doi: 10.1369/0022155420937371. PubMed DOI PMC

Grausova L, et al. Molecular markers of adhesion, maturation and immune activation of human osteoblast-like MG 63 cells on nanocrystalline diamond films. Diam. Relat. Mater. 2009;18:258–263. doi: 10.1016/j.diamond.2008.10.023. DOI

Krátká M, et al. Gamma radiation effects on diamond field-effect biosensors with fibroblasts and extracellular matrix. Colloids Surf. B. 2021;204:111689. doi: 10.1016/j.colsurfb.2021.111689. PubMed DOI

Al-Romaih K, et al. Chromosomal instability in osteosarcoma and its association with centrosome abnormalities. Cancer Genet. Cytogenet. 2003;144:91–99. doi: 10.1016/S0165-4608(02)00929-9. PubMed DOI

Pautke C, et al. Characterization of osteosarcoma cell lines MG-63, Saos-2 and U-2 OS in comparison to human osteoblasts. Anticancer Res. 2004;24:3743–3748. PubMed

Nemcakova I, Jirka I, Doubkova M, Bacakova L. Heat treatment dependent cytotoxicity of silicalite-1 films deposited on Ti-6Al-4V alloy evaluated by bone-derived cells. Sci. Rep. 2020 doi: 10.1038/s41598-020-66228-x. PubMed DOI PMC

Chen S, et al. Adenovirus encoding BMP-7 immobilized on titanium surface exhibits local delivery ability and regulates osteoblast differentiation in vitro. Arch. Oral Biol. 2013;58:1225–1231. doi: 10.1016/j.archoralbio.2013.03.019. PubMed DOI

Zhou L, Wu J, Wu D, Yu J. Surface functionalization of titanium with BMP-7/RGD/hyaluronic acid for promoting osteoblast functions. J. Biomater. Tissue Eng. 2019;9:32–39. doi: 10.1166/jbt.2019.1938. DOI

Franchi M, et al. Osteogenesis and morphology of the peri-implant bone facing dental implants. Sci. World J. 2004;4:1083–1095. doi: 10.1100/tsw.2004.211. PubMed DOI PMC

Witek L, et al. Assessing osseointegration of metallic implants with boronized surface treatment. Med. Oral Patol. Oral Cir. Bucal. 2020;25:e311–e317. doi: 10.4317/medoral.23175. PubMed DOI PMC

Soto-Peñaloza D, et al. Effect on osseointegration of two implant macro-designs: A histomorphometric analysis of bicortically installed implants in different topographic sites of rabbit's tibiae. Med. Oral Patol. Oral Cir. Bucal. 2019;24:e502–e510. doi: 10.4317/medoral.22825. PubMed DOI PMC

Karazisis D, et al. The role of well-defined nanotopography of titanium implants on osseointegration: Cellular and molecular events in vivo. Int. J. Nanomed. 2016;11:1367–1382. doi: 10.2147/ijn.s101294. PubMed DOI PMC

Bissinger O, et al. Comparative 3D micro-CT and 2D histomorphometry analysis of dental implant osseointegration in the maxilla of minipigs. J. Clin. Periodontol. 2017;44:418–427. doi: 10.1111/jcpe.12693. PubMed DOI

Gabler C, et al. Quantification of osseointegration of plasma-polymer coated titanium alloyed implants by means of microcomputed tomography versus histomorphometry. Biomed. Res. Int. 2015;2015:103137. doi: 10.1155/2015/103137. PubMed DOI PMC

Schouten C, Meijer GJ, van den Beucken JJ, Spauwen PH, Jansen JA. The quantitative assessment of peri-implant bone responses using histomorphometry and micro-computed tomography. Biomaterials. 2009;30:4539–4549. doi: 10.1016/j.biomaterials.2009.05.017. PubMed DOI

Linder L. Osseointegration of metallic implants. I. Light microscopy in the rabbit. Acta Orthop. Scand. 1989;60:129–134. doi: 10.3109/17453678909149239. PubMed DOI

Yang JHC, Teii K. Mechanism of enhanced wettability of nanocrystalline diamond films by plasma treatment. Thin Solid Films. 2012;520:6566–6570. doi: 10.1016/j.tsf.2012.06.041. DOI

Grieten L, et al. Real-time study of protein adsorption on thin nanocrystalline diamond. Phys. Status Solidi (A) 2011;208:2093–2098. doi: 10.1002/pssa.201100122. DOI

Hunziker EB, et al. The slow release of BMP-7 at a low dose accelerates dental implant healing in an osteopenic environment. Eur. Cell Mater. 2021;41:170–183. doi: 10.22203/eCM.v041a12. PubMed DOI

Botticelli D, Lang NP. Dynamics of osseointegration in various human and animal models - A comparative analysis. Clin. Oral Implants Res. 2017;28:742–748. doi: 10.1111/clr.12872. PubMed DOI