Quality Assessment of Five Randomly Chosen Ceramic Oral Implant Systems: Cleanliness, Surface Topography, and Clinical Documentation

Received: 16 July 2019; Accepted: 19 August 2019; Published: 22 August 2019

Abstract: (1) Background: This paper aimed to compare the cleanliness of clinically well-documented implant systems with implants providing very similar designs. The hypothesis was that three well-established implant systems from Dentsply Implants, Straumann, and Nobel Biocare were not only produced with a higher level of surface cleanliness but also provided significantly more comprehensive published clinical documentation than their correspondent look-alike implants from Cumdente, Bioconcept, and Biodenta, which show similar geometry and surface structure. (2) Methods: Implants were analyzed using SEM imaging and energy-dispersive X-ray spectroscopy to determine the elemental composition of potential impurities. A search for clinical trials was carried out in the PubMed database and by reaching out to the corresponding manufacturer. (3) Results: In comparison to their corresponding look-alikes, all implants of the original manufacturers showed—within the scope of this analysis—a surface free of foreign materials and reliable clinical documentation, while the SEM analysis revealed significant impurities on all look-alike implants such as organic residues and unintended metal particles of iron or aluminum. Other than case reports, the look-alike implant manufacturers provided no reports of clinical documentation. (4) Conclusions: In contrast to the original implants of market-leading manufacturers, the analyzed look-alike implants showed significant impurities, underlining the need for periodic reviews of sterile packaged medical devices and their clinical documentation.

Keywords: dental implants; surface properties; titanium; materials testing; implant contamination; implant surface; scanning electron microscopy; energy-dispersive X-ray spectrometry

1. Introduction
The advent of osseointegration has led to a clinical breakthrough in oral implants. Minimally rough, turned implants were the first osseointegrated oral implants used, with the first patient treated in 1965 [1]. These turned screws remain the most clinically documented implants of all with 75% of all studies in long-term reports [2]. Over time, other clinically documented oral implant systems have increasingly begun to be used. Those systems may have preferred slightly different surfaces; moderately rough implants have been the treatment of choice since the turn of the millennium, since they have demonstrated improved clinical results [3]. The surface of moderately rough implant systems may be manufactured in different ways, by subtractive methods such as the combination of blasting and acid etching or anodization and by additive techniques, such as hydroxyapatite coating. Products from what are regarded as the three largest oral implant companies in the world including Osseo Speed implants from Dentsply–Sirona, SLA-implants from Straumann and TiUnite implants from Nobel Biocare, have been clinically documented in numerous papers spanning a period of over 5 to over 10 years of follow up with very high levels of survival and success [4–6].
Since some osseointegrated oral implant systems have been duly documented with a very good clinical outcome, numerous new implant manufacturers have tried to mimic the surfaces and geometries presented by the leading companies. These are so called copy-cat or at least “look-alike” implant systems which usually lack clinical documentation of their own but claim to be as good as the original implants they are trying to mimic. However, in clinical reality these implants lack the scientific evidence of similar performance.
One surface characteristic of sterile packaged oral implants is their cleanliness. Oral implants may display different surface of an inorganic or organic nature. These impurities may derive from the manufacturing handling and packaging processes and may remain on the commercially available implant. We are presently lacking in knowledge of the precise clinical risks of implant impurities. However, contaminations are technically avoidable and, generally speaking, the authors assume all of us would prefer clean implants to avoid potential problems from surface impurities.
The aim of the present paper was to compare the cleanliness of proper clinically documented implant systems with implants that are very similar in design and surface; OsseoSpeed from Dentsply Implants was compared to a German look-alike implant called Cumdente; Standard Plus Implant SLA from Straumann was compared to a Chinese look-alike implant called Bioconcept (claiming to be 100% compatible with Straumann); and a TiUnite-surfaced implant NobelActive from Nobel Biocare was compared to a Swiss/Taiwanese implant system called Biodenta. Our hypothesis was that the three major and well-established implant systems have significantly comprehensive clinical documentation and have their implants produced in a significantly cleaner manner than would the respective look-alike systems.
Every single dental implant has to be clean, as this is a medical device that could harm patients—even if we found one single implant with impurities, this implant was intentionally sold for the therapy of one real patient. This paper was not intended to show a statistically relevant number of average contaminations for specific implant types. All implants in this study were randomly purchased and labeled for clinical use. Each sample of these medical devices was produced using a certain regime of quality management. If the quality management of a manufacturer cannot ensure a certain level of cleanliness, a single implant with significant impurities, which are technically avoidable, is proof of a lack of quality.

2. Experimental Section
Implant types used for this analysis were the following: Astra Tech–Dentsply Implants (OsseoSpeed EV, Mölndal, Sweden), Straumann (Standard Plus SLA Implant, Zürich, Switzerland), Nobel Biocare (NobelActive Internal RP, Zürich, Switzerland), Cumdente (AS Implant, Tübingen, Germany), Bioconcept (Tissue Level Implant, Jiangsu, China), Biodenta (Dental Implant, Bernek, Switzerland). The three implants from market-leading manufacturers and the correspondent three look-alike implants were purchased in the period between March 2018 and May 2019, either by ghost-shopping, where the ordering practice was reimbursed from the research fund or by direct order. In all six cases, the manufacturers or the respective distributors were not informed about the purpose of the implant order. None of the samples were provided free of charge. Prices varied from 191 euro to 322 euro for the samples of market-leading brands and from 78 euro to 276 euro for the look-alike products.
All of the six samples collected were carefully unpacked, mounted on the sample holder on carbon tabs without touching the implant surface, and analyzed with a scanning electron microscope (SEM) in a particle-free clean room environment (according Class 100 US Federal Standard 209E, Class 5 DIN
J. Clin. Med. 2019, 8, 1280 3 of 18 EN ISO 14644-1) to avoid artifacts from the ambient air (Figure 1).

Figure 1.. IImpllantt ssamplle wiitth a llengtth off 10 mm mounted on the SEM sample holder.
The scientific workstation used was a Phenom proX Scanning Electron Microscope (Eindhoven,
The scientific workstation used was a Phenom proX Scanning Electron Microscope (Eindhoven,
Netherlands), equipped with a high-sensitivity backscattered electron (BSE) detector. The detector
Netherlands), equipped with a high-sensitivity backscattered electron (BSE) detector. The detector
for the energy-dispersive X-ray spectroscopy (EDS) and elemental analysis was a thermoelectrically
for the energy-dispersive X-ray spectroscopy (EDS) and elemental analysis was a thermoelectrically
2 cooled silicon drift detector (SDD) type, with an active detector area of 25 mm2. cooled silicon drift detector (SDD) type, with an active detector area of 25 mm .
The high-sensitivity BSE detector allows a magnification of up to 100,000× with a resolution The high-sensitivity BSE detector allows a magnification of up to 100,000× with a resolution
down to 15 nm. This study used material-contrast images from 500× to a magnification of 5000×. down to 15 nm. This study used material-contrast images from 500× to a magnification of 5000×.
Material-contrast imaging gave additional information about the chemical nature and allocation of
Material-contrast imaging gave additional information about the chemical nature and allocation of
different remnants or contaminations on the sample material. different remnants or contaminations on the sample material.
In order to achieve a complete overview of the horizontally mounted implant sample and
In order to achieve a complete overview of the horizontally mounted implant sample and
comprehensive surface quality information in high resolution, implants were scanned at a magnification
comprehensive surface quality information in high resolution, implants were scanned at a
of 500× in the “Image-Mapping” mode prior to the detailed analysis of potential impurities. magnification of 500× in the “Image-Mapping” mode prior to the detailed analysis of potential
This technique produces up to 600 single high-resolution SEM images of the implant surface that
impurities. This technique produces up to 600 single high-resolution SEM images of the implant
were digitally composed into one large image, with an extremely high resolution. The composed
surface that were digitally composed into one large image, with an extremely high resolution. The
SEM image, showing the full size of the implant from shoulder to apex, made it possible to count
composed SEM image, showing the full size of the implant from shoulder to apex, made it possible
particles in the visible field (viewing angle of approximately 120◦) and to identify areas of interest to count particles in the visible field (viewing angle of approximately 120°) and to identify areas of
for a subsequent EDS spot analysis. After the mapping process, SEM images of impurities and other
interest for a subsequent EDS spot analysis. After the mapping process, SEM images of impurities
regions of interest were produced with 500×, 1000× 2500×, and 5000× magnification. In the next step, and other regions of interest were produced with 500×, 1000× 2500×, and 5000× magnification. In the
the elemental composition of particles was determined and, where possible, the differential spectra of next step, the elemental composition of particles was determined and, where possible, the
particles were achieved to subtract signals from the core material and such focus on signals from the
differential spectra of particles were achieved to subtract signals from the core material and such
superficial contamination (Figure 2).
focus on signals from the superficial contamination (Figure 2).
focus on signals from the superficial Figure 2. Workflow of the SEM/EDS analysis. Figure 2. Workflow of the SEM/EDS analysis.
All of the analyses, as well as the complete setup, as described above were performed at the
All of the analyses, as well as the complete setup, as described above were performed at the
Medical Materials Research Institute, Berlin, Germany, which is an officially accredited (Deutsche Medical Materials Research Institute, Berlin, Germany, which is an officially accredited (Deutsche Akkreditierungsstelle–DAkkS) and externally audited testing laboratory according to the international Akkreditierungsstelle–DAkkS) and externally audited testing laboratory according to the
standards DIN EN ISO 9001:2015, ISO 22309:2015 and DIN EN ISO/IEC 17025. These standards were international standards DIN EN ISO 9001:2015, ISO 22309:2015 and DIN EN ISO/IEC 17025. These
chosen as a precondition in order to assure testing procedures at the highest level of accuracy.
standards were chosen as a precondition in order to assure testing procedures at the highest level of
In addition to the SEM/EDS analysis, all of the implants in this study were provisionally evaluated accuracy.
from a surface topographical point of view by interferometry. All implants seemed to be in the
In addition to the SEM/EDS analysis, all of the implants in this study were provisionally
moderately rough surface range, i.e., with Sa (Sa = arithmetical mean height of the surface) values of evaluated from a surface topographical point of view by interferometry. All implants seemed to be
between 1 and 2 micrometers.
in the moderately rough surface range, i.e., with Sa (Sa = arithmetical mean height of the surface) values of between 1 and 2 micrometers.
2.1. Clinical Documentation of Analyzed “Look-Alike” Implant Systems
A search for available clinical trial regarding the dental implant systems was carried out. Initially
2.1. Clinical Documentation of Analyzed “Look-Alike” Implant Systems
the website of each dental implant manufacturer was searched (www.biodenta.com, www.bioconcept.cn, A search for available clinical trial regarding the dental implant systems was carried out.
www.cumdente.com). In addition, the manufacturers were contacted via their respective contact e-mail Initially the website of each dental implant manufacturer was searched (www.biodenta.com,
address on their websites, requesting any scientific documentation regarding clinical performance such
www.bioconcept.cn, www.cumdente.com). In addition, the manufacturers were contacted via their
as published papers or summaries of ongoing projects. If no response was received within one week, a
respective contact e-mail address on their websites, requesting any scientific documentation
reminder was sent.
regarding clinical performance such as published papers or summaries of ongoing projects. If no
Furthermore, a search for clinical trials was performed in the PubMed database (PubMed.gov,
response was received within one week, a reminder was sent.
US National Library of Medicine, National Institutes of Health). The search terms “dental implants”
Furthermore, a search for clinical trials was performed in the PubMed database (PubMed.gov,
(MeSH) and “dental implants” (free text) were used in combination with the product name “Biodenta”,
US National Library of Medicine, National Institutes of Health). The search terms “dental implants”
“Bioconcept”, and “Cumdente”. No limits were set. ((“dental implants” [MeSH Terms] OR (“dental”
(MeSH) and “dental implants” (free text) were used in combination with the product name
[All Fields] AND “implants” [All Fields]) OR “dental implants” [All Fields]) AND biodenta [All
“Biodenta”, “Bioconcept”, and “Cumdente”. No limits were set. ((“dental implants” [MeSH Terms]
Fields]), ((“dental implants” [MeSH Terms] OR (“dental” [All Fields] AND “implants” [All Fields]) OR
OR (“dental” [All Fields] AND “implants” [All Fields]) OR “dental implants” [All Fields]) AND
“dental implants” [All Fields]) AND bioconcept [All Fields], ((“dental implants” [MeSH Terms] OR
biodenta [All Fields]), ((“dental implants” [MeSH Terms] OR (“dental” [All Fields] AND “implants”
(“dental” [All Fields] AND “implants” [All Fields]) OR “dental implants” [All Fields]) AND cumdente
[All Fields]) OR “dental implants” [All Fields]) AND bioconcept [All Fields], ((“dental implants”
[All Fields])).
[MeSH Terms] OR (“dental” [All Fields] AND “implants” [All Fields]) OR “dental implants” [All F2i.e2l.dCs]li)nAicNalDoccuumdeenntatteio[nAollf FOiessldeosS])p)e.ed, SLA, and TiUnite Implant Systems
With respect to the implant systems OsseoSpeed from Dentsply-Sirona, SLA from Straumann,
2.2. Clinical Documentation of OsseoSpeed, SLA, and TiUnite Implant Systems
and TiUnite from Nobel Biocare, these belong to the most clinically documented oral implant systems
With respect to the implant systems OsseoSpeed from Dentsply-Sirona, SLA from Straumann,
in the world [2]. To remain brief, we decided to only quote five papers for each system as the total and TiUnite from Nobel Biocare, these belong to the most clinically documented oral implant
number of clinical reports on these devices amounts to several hundred scientific papers.
systems in the world [2]. To remain brief, we decided to only quote five papers for each system as
3. Results
the total number of clinical reports on these devices amounts to several hundred scientific papers.
3.1. SEM Imaging and Elemental Analysis
3. Results
Implants were analyzed in three groups. In the first group, the implant from Astra Tech–Dentsply
3.1. SEM Imaging and Elemental Analysis
Implants (OsseoSpeed) and the implant from Cumdente (AS Implant) were compared. The full-size SEM image of the Astra Tech implant—digitally composed of 455 single SEM images (tiles)—showed a
full-size SEM image of the Astra Tech implant—digitally composed of 455 single SEM images
homogenous surface with no foreign material (Figure 3).

Figure 4. OsseoSpeed surface: (a) the red marked area in Figure 3 magnified 500×; (b) higher magnification (2500×) of the white marked area in the left image with EDS spot analysis of an
magnification (2500×) of the white marked area in the left image with EDS spot analysis of an embedded
(a) (b)
embedded TiO2-particle (spot is marked with “+” in the red circle) showing only signals of the TiO2-particle (spot is marked with “+” in the red circle) showing only signals of the blasting material.
blasting material.
Figure 4. OsseoSpeed surface: (a) the red marked area in Figure 3 magnified 500×; (b) higher
Higher magnification could identify the TiO particles from the blasting process seen as magnification (2500×) of the white marked area in2the left image with EDS spot analysis of an
The Cumdente implant showed several anomalies in the correspondent full-size image,
sharp-edged particles of 5–10 mm embedded in the titanium surface. Elemental analysis of these
embedded TiO2-particle (spot is marked with “+” in the red circle) showing only signals of the composed of 422 tiles (Figure 5).
particlebslaostninlyg mdiastperlaiayl.ed signals of titanium and oxygen (Figure 4).
The Cumdente implant showed several anomalies in the correspondent full-size image, composed
The Cumdente implant showed several anomalies in the correspondent full-size image,
of 422 tiles (Figure 5).

Figure 5. SEM mapping of the AS Implant (Cumdente); Red marked area—see magnification in Figure 5. SEM mapping of the AS Implant (Cumdente); Red marked area—see magnification in
The SEM images with higher magnification revealed systematic contamination with multiple Figure 6, blue marked area—see magnification in Figure 7, green marked area—see magnification in
Figure 6, blue marked area—see magnification in Figure 7, green marked area—see magnification in (>100) organic particles (5–60 μm) on exposed parts of the implant, as seen on the micro-threads next
Figure 8.
Figure 8.

Figure 6. AS Implant (Cumdente) with organic particles (10–50 μm) at the implant shoulder: (a) systematic contamination of exposed threads, red marked area of Figure 5 in 500×; (b) magnification
systematic contamination of exposed threads, red marked area of Figure 5 in 500×; (b) magnification (a) (b)
(5000×) of white marked area in the left image. The EDS differential measurement of the marked
(5000×) of white marked area in the left image. The EDS differential measurement of the marked spots Fspigoutsrew6a.sAidSenItmicpalatnotth(Ceupmardtiecnletes)inwFitihguorreg7a.nic particles (10–50 μm) at the implant shoulder: (a)
was identical to the particles in Figure 7.

FiFgiugruere7.7A. ASSImImpplalanntt(C(Cuumddeentte))wiith organic particlles((5–7700μm))aatttthheeimimpplalannt’ts’sapapexe:x(:a()ab)lbuleue measurement revealed more precise information about the elemental composition of the foreign
mmarakrekdedaraeraeaofofFFigiguurere55inin500×; (b) magnififiiccaatitoionn(5(0500×0)×o)fowf hwitheitmeamrkaerdkeadrearienaFiinguFrigeu7r(ea)7;aE;DESDS material. Figure 8 shows the differential EDS measurement of the particle in Figure 7, with a clear
didffiefrfenretniatliaml meaesausruermemenetnotfofmmaarkrkeeddssppootstsisissshowninFigure8.