Fatigue of Narrow Dental Implants: Influence of the Hardening Method.

R.A. Pérez,J. Gargallo,M. Herrero-Climent,F.J. Gil,P. Altuna

doi:10.3390/ma13061429

R.A. Pérez, J. Gargallo + Show 3 more

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https://doi.org/10.3390/ma13061429

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Abstract

The use of narrow titanium dental implants (NDI) for small ridges, reduced interdental space, or missing lateral incisors can be a viable option when compared to the conventional wider dental implants. Furthermore, in many cases, standard diameter implant placement may not be possible without grafting procedures, which increases the healing time, cost, and morbidity. The aim of this study was to analyze the mechanical viability of the current narrow implants and how narrow implants can be improved. Different commercially available implants (n = 150) were tested to determine maximum strength, strain to fracture, microhardness, residual stress, and fatigue obtaining the stress–number of cycles to fracture (SN) curve. Fractography was studied by scanning electron microscopy. The results showed that when the titanium was hardened by the addition of 15% of Zr or 12% cold worked, the fatigue limit was higher than the commercially pure grade 4 Ti without hardening treatment. Grade 4 titanium without hardening treatment in narrow dental implants can present fractures by fatigue. These narrow implants are subjected to high mechanical stresses and the mechanical properties of titanium do not meet the minimal requirements, which lead to frequent fractures. New hardening treatments allow for the mechanical limitations of conventional narrow implants to be overcome in dynamic conditions. These hardening treatments allow for the design of narrow dental implants with enhanced fatigue life and long-term behavior.

Highlights

Severe alveolar ridge reduction caused by periodontal diseases, trauma, or tooth loss can result in a reduced amount of bone in which to place regular diameter implants
Different studies indicate the need for a minimum bone space of 1.5 to 2 mm between a tooth and the implant and 3 mm between implants due to the tissues that should be accommodated, producing a correct function and esthetics [3]
The mechanical strength of commercially pure titanium is sometimes insufficient for the long lasting integrity of titanium implants [4], and the use of narrow dental implants represents a major risk of fractures [5,6,7]

Summary

Introduction

Severe alveolar ridge reduction caused by periodontal diseases, trauma, or tooth loss can result in a reduced amount of bone in which to place regular diameter implants. In these cases, bone regenerative techniques have been highly described to increase the bone tissue volume simultaneously or before implant placement [1,2]. The mechanical strength of commercially pure titanium is sometimes insufficient for the long lasting integrity of titanium implants [4], and the use of narrow dental implants represents a major risk of fractures [5,6,7]. Clinicians should be aware of the mechanical problems of dental

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