Random spectrum loading of dental implants: An alternative approach to functional performance assessment

• Published in: Journal of the mechanical behavior of biomedical materials 2016-09, Vol.62, p.1-9
• Main Authors: Shemtov-Yona, K., Rittel, D.
• Format: Article
• Language: English
• Subjects: Dental Implants; Dental Prosthesis Design; Dental Restoration Failure; Dental Stress Analysis; Mechanical performance; Random spectrum loading; Stress, Mechanical; Titanium
• ISSN: 1751-6161; 1878-0180
• DOI: 10.1016/j.jmbbm.2016.04.030

The fatigue performance of dental implants is usually assessed on the basis of cyclic S/N curves. This neither provides information on the anticipated service performance of the implant, nor does it allow for detailed comparisons between implants unless a thorough statistical analysis is performed, of the kind not currently required by certification standards. The notion of endurance limit is deemed to be of limited applicability, given unavoidable stress concentrations and random load excursions, that all characterize dental implants and their service conditions. We propose a completely different approach, based on random spectrum loading, as long used in aeronautical design. The implant is randomly loaded by a sequence of loads encompassing all load levels it would endure during its service life. This approach provides a quantitative and comparable estimate of its performance in terms of lifetime, based on the very fact that the implant will fracture sooner or later, instead of defining a fatigue endurance limit of limited practical application. Five commercial monolithic Ti-6Al-4V implants were tested under cyclic, and another 5 under spectrum loading conditions, at room temperature and dry air. The failure modes and fracture planes were identical for all implants. The approach is discussed, including its potential applications, for systematic, straightforward and reliable comparisons of various implant designs and environments, without the need for cumbersome statistical analyses. It is believed that spectrum loading can be considered for the generation of new standardization procedures and design applications. •A new methodology to assess the functional performance of dental implants is proposed.•Random spectrum loading is used as an alternative to traditional cyclic tests.•The performance until fracture is evaluated instead of the fatigue limit.•The approach allows for a rapid assessment of the implant with minimal statistics.•Different implant designs or materials can be readily and reliably compared.