Abstract
An investigation into the surface texture evaluation of titanium dental implants was carried out.
Surface modifications of dental implants are commonplace, albeit by different mechanisms and
processes (machining, blasting, coatings, etc.), with the purpose of optimising and/or enhancing
implant performance. Regardless of the reasoning behind surface modification, reliable and
consistent evaluation techniques and methodologies are required by both researchers and
manufacturers of the implants. Researchers would require consistent evaluation methods for
comparative purposes, and manufacturers in order to produce surfaces that meet certain texture
descriptor targets or fall within a specified texture descriptor ranges. Following a similar train of
thought; perhaps even more fundamental is the concept of surface texture evaluation and its
applicability to surface texture, and how the required/desired surface texture descriptor values were
established in the first place. Commercially pure grade 4 titanium (cpTi‐Gr4) dental implants that
featured surfaces modified by an aluminium oxide blasting process were selected for use as tangible
samples for the purposes of carrying out the investigation.
A review of the recent published literature specifically relating to titanium dental implants and their
surface texture was conducted – a total of 57 journal articles were identified for the period between
2001 and 2015. It was found that while standards do exist for roughness evaluation, there were no
set standards used in the texture evaluation of dental implants. The standards referred to in some of
the articles specified ranges of evaluation parameters based upon a range of length scales, however
there were neither agreed upon nor stated length scales set by researchers for dental implant
texture evaluations. This observation implied that evaluation parameters are required to explicitly
state the conditions under which roughness descriptors are measured and determined, however it is
apparent that this is not a requirement for many publications. It was noted that only 1 out of the 57
reviewed articles gave enough evaluation parameter information to repeat the measurement
methodology it followed. As a consequence it follows that many of the published research articles
gave texture quantities which are difficult, if not impossible, to meaningfully relate to one another.
Even in the cases where identical roughness descriptor results were published, information
regarding the acquisition of the surface descriptors was generally absent. Equivalence of surface
descriptor values across articles was therefore tenuous at best. It was concluded that most authors
used standards (ISO) in their evaluations, and as such a filtering cut‐off length of 800 μm (λc = 0.8
mm) was the ‘default’. To complicate the issue further, it was found that most authors gave profile
roughness results, while some gave areal roughness results. Profile roughness descriptors are
suitable for isotropic surfaces, however areal descriptors are better suited for anisotropic surfaces.
Areal analysis is the preferred regime in this research.
A related topic to the reviewed articles was the instrumentation used to carry out surface texture
evaluations of the titanium dental implants. Scanning electron microscopy (SEM) (single image) was
the most popular tool, followed by atomic force microscopy (AFM) and contact stylus profilometry
(CSP). It is noted that single image SEM has primarily been used as qualitative tool since the images
generally do give a surface height, whereas the AFM and CSP output height values which are easily
converted into texture descriptors by modern instrument control software. Advantages and
disadvantages of the instruments were identified; SEM (single image) could examine a wide range of...
M.Ing. (Mechanical Engineering)