title: Biomechanical and histological evaluation of the osseointegration capacity of two types of zirconia implant.
abstract: The purpose of this study was to evaluate the biomechanical and histological behavior of a ceria-stabilized zirconia-alumina nanocomposite (NanoZr) in comparison with that of 3 mol% yttria-stabilized tetragonal zirconia polycrystalline (3Y-TZP) in Sprague Dawley rats. Cylindrical NanoZr and 3Y-TZP implants (diameter 1 mm, length 2 mm) were used. Implant-surface morphology and surface roughness were determined by scanning white-light interferometry and scanning electron microscopy, respectively. The cylindrical zirconia implants were placed at the distal edge of the femur of Sprague Dawley rats. At weeks 2, 4, and 8, the interfacial shear strength between implant and bone was measured by push-in test. Histological analysis was performed using hard-tissue sections. Bone-implant contact (BIC), the thickness of new bone around the implant within the bone marrow area, and osteoclast numbers were evaluated. The average surface roughness of 3Y-TZP (Sa 0.788 μm) was significantly higher than that of NanoZr (Sa 0.559 μm). The shear strengths of 3Y-TZP and NanoZr were similar at 2 weeks, but at 4 and 8 weeks the shear strength of NanoZr was higher than that of 3Y-TZP. The average BIC values within the bone marrow area for 3Y-TZP and NanoZr were 25.26% and 31.51% at 2 weeks, 46.78% and 38% at 4 weeks, and 47.88% and 56.81% at 8 weeks, respectively. The average BIC values within the cortical area were 38.86% and 58.42% at 2 weeks, 66.82% and 57.74% at 4 weeks, and 79.91% and 78.97% at 8 weeks, respectively. The mean BIC value did not differ significantly between the two zirconia materials at any time point. The NanoZr implants were biocompatible, capable of establishing close BIC, and may be preferred for metal-free dental implants.
authors.affiliation: Department of Dental Materials, National Engineering Laboratory for Digital and Material Technology of Stomatology, Peking University School and Hospital of Stomatology, Beijing, People's Republic of China; Division of Advanced Prosthetic Dentistry.
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Han
authors.affiliation: Liaison Center for Innovative Dentistry.
authors.forename: Guang
authors.initials: G
authors.lastname: Hong
authors.affiliation: Department of Dental Materials, National Engineering Laboratory for Digital and Material Technology of Stomatology, Peking University School and Hospital of Stomatology, Beijing, People's Republic of China.
authors.forename: Hong
authors.initials: H
authors.lastname: Lin
authors.affiliation: Department of Oral Pathology, Graduate School of Dentistry, Tohoku University, Sendai, Japan.
authors.forename: Yoshinaka
authors.initials: Y
authors.lastname: Shimizu
authors.affiliation: Division of Advanced Prosthetic Dentistry.
authors.forename: Yuhan
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Dental Materials, National Engineering Laboratory for Digital and Material Technology of Stomatology, Peking University School and Hospital of Stomatology, Beijing, People's Republic of China.
authors.forename: Gang
authors.initials: G
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing, People's Republic of China.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Division of Advanced Prosthetic Dentistry.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Sasaki
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D000818:Animals; D001696:Biomechanical Phenomena; D002563:Cerium / Q000737:chemistry; D015921:Dental Implants; D005269:Femur / Q000473:pathology / Q000601:surgery*; D006652:Histological Techniques; D016348:Osseointegration / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties; D015019:Yttrium / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
chemical_list: D015921:Dental Implants; D002563:Cerium; D015019:Yttrium; C030583:ceric oxide; D015040:Zirconium; D000537:Aluminum Oxide
keywords: dental implant; histomorphometry; push-in test; zirconia; zirconia–alumina nanocomposite