title: Mechanical properties of human bone surrounding plateau root form implants retrieved after 0.3-24 years of function.
abstract: Bone remodeling, along with tissue biomechanics, is critical for the clinical success of endosseous implants. This study evaluated the long-term evolution of the elastic modulus (GPa) and hardness (GPa) of cortical bone around human retrieved plateau root form implants. Thirty implant-in-bone specimens showing no clinical failure were retrieved from patients at different in-vivo times (0.3 to ~24 years) due to retreatment needs. After dehydration, specimens were embedded in methacrylate-based resin, sectioned along the bucco-lingual long axis and fixed to acrylic plates and nondecalcified processed to slides with ~50 μm in thickness. Nanoindentation testing was carried out under wet conditions on bone areas within the first three plateaus. Indentations (n = 120 per implant total) were performed with a maximum load of 300 μN (loading rate: 60 μN/s) followed by a holding and unloading time of 10 s and 2 s, respectively. Elastic modulus (E, GPa) and hardness (H, GPa) were computed. Both E and H values presented increased values as time in vivo elapsed (E: r = 0.84; H: r = 0.78). Significantly higher values for E and H were found after 5 years in vivo (p < 0.001). Maxillary or mandibulary arches or positioning did not affect mechanical properties, nor did implant surface treatment on the long-term bone biomechanical response (E: p ≥ 0.09; H: p ≥ 0.3). This work suggests that human cortical bone around plateau root form implants presents an increase in elastic modulus and hardness during the first 5 years following implantation and presents stable mechanical properties thereafter.
authors.affiliation: Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, USA. mb3577@nyu.edu
authors.forename: Marta
authors.initials: M
authors.lastname: Baldassarri
authors.forename: Estevam
authors.initials: E
authors.lastname: Bonfante
authors.forename: Marcelo
authors.initials: M
authors.lastname: Suzuki
authors.forename: Charles
authors.initials: C
authors.lastname: Marin
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Granato
authors.forename: Nick
authors.initials: N
authors.lastname: Tovar
authors.forename: Paulo G
authors.initials: PG
authors.lastname: Coelho
mesh_terms: D000328:Adult; D000368:Aged; D055119:Elastic Modulus; D005260:Female; D006801:Humans; D008297:Male; D008341:Mandibular Prosthesis; D008447:Maxillofacial Prosthesis; D008875:Middle Aged; D013997:Time Factors