title: Implant fracture under dynamic fatigue loading: influence of embedded angle and depth of implant.
abstract: The purpose of this study was to investigate the relationship between implant fracture under cyclic-fatigue loading at different embedding angles, embedding depths, and loading forces. Twenty-four cylinder-type implants 3.3 mm in diameter and 10 mm in length were used. Test specimens were 30 mm(3) resin blocks with one surfaces inclined at angles of either 5°, 10°, 15° and 20° and embedded vertically with implants at depths of either 5 or 10 mm to the these surfaces. A straight abutment was connected to the implant and cut to 5 mm in length, and a hemispherical crown 5 mm in diameter and 7 mm in length was cast with a 12 % gold-silver-palladium alloy and cemented onto the abutment. Each specimen was mounted onto a fatigue loading device to apply repeated vertical loads of 294, 392, and 490 N to the coronal edge of the crown 60 times per min until reaching 100,000 cycles. For each respective specimen, we recorded the combined conditions of embedding and loading forces and the number of loading cycles until fracture, and then observed the fracture sites microscopically. The number of loading cycles until implant fracture tended to decrease in proportion to increased loading forces and embedded angles, and decreased embedded depths. Implant fracture was observed at angles of inclination over 10°. For specimens with an implant embedded at a depth of 5 mm, almost all fractures occurred at the center of the implant body; however, for those embedded at a depth of 10 mm, fractures occurred at the interface between the implant body and the abutment. These results demonstrate that implant fracture is associated with the loading axis, the amount of loading, and the embedded depth of the implant.
authors.affiliation: Department of Crown and Bridge Prosthodontics, The Nippon Dental University School of Life Dentistry at Niigata, Hamaura-chou 1-8, Chuuou-ku, Niigata, 951-8580, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Department of Crown and Bridge Prosthodontics, The Nippon Dental University School of Life Dentistry at Niigata, Hamaura-chou 1-8, Chuuou-ku, Niigata, 951-8580, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Hata
authors.affiliation: Department of Crown and Bridge Prosthodontics, The Nippon Dental University School of Life Dentistry at Niigata, Hamaura-chou 1-8, Chuuou-ku, Niigata, 951-8580, Japan. fumi@ngt.ndu.ac.jp.
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Watanabe
mesh_terms: D003442:Crowns; D003722:Dental Alloys / Q000737:chemistry*; D059605:Dental Implant-Abutment Design; D015921:Dental Implants; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D066298:In Vitro Techniques; D008422:Materials Testing; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D003722:Dental Alloys; D015921:Dental Implants
keywords: Bending force; Cyclic-fatigue loading; Implant axis; Implant fracture; Loading angle