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Identification Cards of 14 Implant SurfacesTABLEComplete codification system for the microtopography of osseointegrated implant surfacesRPa/PoX-PtSMiMoMaFlFoRueRuHTA, Pleasanton, Calif) up to 3200 000magnification and the second one with aclassical scanning electron microscope(SEM; LV-6380, JEOL, Tokyo, Japan). All theareas of the implants were carefully examined, from the macroscale to the nanoscale.This examination allowed the various morphological characteristics of the surfaces(cracks, blasting residues, homogeneity) tobe highlighted and allowed for determination of the kind of nanotopography of eachsample (nanosmooth, nanorough, nanopatterned, or nanoparticled).The microtopography was quantifiedusing a light interferometer (IFM, MicroXAM,ADE Phase Shift Inc, Tucson, Ariz), followingthe guidelines suggested in 2000,36 that is,evaluating the topography on the top,valley, and flank of 3 successive threadsand calculating the corrected mean valuesof these large areas. The dimensions of theanalyzed areas were 200 3 260 mm most ofthe time, but the area could be a little bitsmaller depending on the implant macrogeometry. An IFM three-dimensional reconstruction picture was used in each ID card toillustrate the general aspect of the microtopography. Several topographical parameters were assessed, but only 2 were considered significant for the classification of thesurface characteristics: the Sa (height deviation amplitude of the microtopography, also528Vol. XXXVII/No. Five/20111/ Morphology Type (No. of dimensions [D])Rough (1D)Patterned or Porous (2D)Particle (3D): X 5 elemental composition2/ Height Deviation Amplitude (Sa)Smooth: Sa 5 0 to 0.5 mmMinimal: Sa 5 0.5 to 1 mmModerate: Sa 5 1 to 2 mmMaximal: Sa . 2 mm3/ Spatial Density (developed area ratio, Sdr%)Flat: Sdr% 5 0 to 50%Flattened out: Sdr% 5 50 to 100%Rugged: Sdr% 5 100 to 200%Extra rugged: Sdr% . 200%called roughness) and the Sdr% (a hybridparameter integrating both the number andheight of peaks of the microtopography).The Sa is an important and frequentparameter for comparing surfaces and hasalready been used in other classifications.40The Sdr% is calculated as a developed arearatio relative to a flat plane baseline. For atotally flat surface, Sdr 5 0%. When Sdr 5100%, it means that the roughness of asurface doubled its developed area.These Sa and Sdr% values allowed forclassification of the microtopography, following the previously developed DEC system. However, we have introduced someminor modifications to the initial classification system: when Sdr% is below 50%, thesurface is labeled ‘‘flat’’, and when theSdr% is above 200%, the surface is labeled‘‘extra rugged’’. The modified classificationsystem for these values is summarized in theTable.RESULTSGeneral considerationsXPS is a very sensitive technique that allowsthe user to determine the relative quantitiesand chemical states of most elementspresent on the surface, main elements andvarious contaminants. The high-resolutionspectra of these analyses allows determina-

Dohan Ehrenfest et altion of the atomic links, and thereforeclarifies the surface chemistry. For example,all the surfaces present significant percentages of carbon, and the XPS clarifies whetherthe carbon is related to adventitious carbonfrom the atmosphere or organic contaminants. The oxygen is associated with titanium oxides, carbon contaminants, and adsorbed water on the superficial layer. It canalso be detected as Al2O3 when aluminablasting residues are present on a surface.For the establishment of the ID cards, theXPS data are only provided in a simplifiedtable of atomic composition, where significant variations are highlighted in bold type,but the high-resolution spectra were used tovalidate the codification of the chemistry ineach card.The AES method allows for the in-depthanalysis of very small areas but with fewerdetails than XPS. Our protocol allowed forthe analysis of the chemical composition ofthe first 100 nm surface thickness, which isthe main interface during the osseointegration. In some surfaces, the percentage ofaluminum quickly reached almost 10% of thetotal composition, and this is typical of grade5 Ti-6Al-4V titanium cores. The AES profileswere often similar between the peaks andvalleys, and the peak profile was used in theID cards. Because of the very small size of theanalysis spot, some elements presenting aheterogeneous distribution and detectedwith XPS were not found with AES. Forexample, alumina-blasting residues weresometimes outside the AES beam, andtherefore were not detected, even if theywere clearly visible with the SEM.The combination of XPS and AES dataallows the TiO2 layer thickness to bedetermined, which is considered importantfor the osseointegration process. Typically,only anodized/oxidized implants (TiUniteand Ospol) have a very thick (micrometric)TiO2 layer, which is considered to increasethe bone/implant chemical interlocking.41 Allthe other blasted and/or etched surfacesonly presented a thin native TiO2 layer(around 6–8 nm), except Ossean, which hada thicker TiO2 layer (.12 nm).The intent of these ID cards is to gatherthe key information about a surface in acompact format, and therefore only a limitednumber of FE-SEM photos can be addedin each card. The FE-SEM photos are notnecessary to show the microscale level ofthe surfaces, as the IFM three-dimensionalreconstruction figures offer a much morerepresentative and reliable illustration of themicrotopography. The FE-SEM photos arethus mainly important for illustrating theglobal architecture of the surface and thenanoscale features. For this reason, a standard magnification of 330 000 was chosenfor the FE-SEM photo used in each card,because this magnification can simultaneously illustrate the microscale morphologyand confirm the absence of significantnanotexture.Sometimes, however, this standard magnification does not show the most importantpatterns of a surface, and another presentationis needed to keep the card reader-friendly andcomplete. When implant surfaces presentsignificant and repetitive nanostructures, it ispreferable to use FE-SEM photos at a highermagnification (3100 000) in order to showthese nanostructures very accurately. A fewsurfaces present large micrometric patterns thatcannot be illustrated properly at the standard330 000 magnification (micropores, extendedcracks). In these cases, it is more logical to use35000 photos to illustrate these surfacesclearly. Consequently, with this low magnification, the nanotopography is no longer visible,and a second photo at a higher magnification(3100 000) must be provided for illustration(even if these photos look very flat when thesurfaces are nanosmooth).Note that all of these analyses have beenperformed and checked many times onmany samples during the preliminary invesJournal of Oral Implantology529

Identification Cards of 14 Implant Surfacestigations to validate this project. Finally, wecollected a last series of standardized datafor the establishment of the ID cards. Thesurfaces were gathered in 4 groups, depending on their production technology.Surfaces from the first groupThe first group gathers all the surfacespresenting a modification of the titaniummetallurgy. This includes mainly anodized ortitanium plasma-sprayed (TPS) surfaces.TiUnite (Figure 1) is an anodized surface,thus presenting a thick TiO2 layer (.100 nm).During anodization, a high quantity of phosphorus is incorporated into the surface as achemical modification. Inorganic fluoride andsulfate pollutions were also detected. Thesurface is microporous (pores created byanodization), is smooth on the nanoscale,and presents extended cracks related to theanodization process.Ospol (Figure 2) is also an anodizedsurface, thus presenting a thick TiO2 layer(.100 nm). During anodization, low quantities of calcium and phosphorus are incorporated into the surface as a chemical modification. Traces of sodium were also detected.The surface is microporous (pores created byanodization), is smooth on the nanoscale,and presents small local cracks related to theanodization process.Kohno HRPS (High Roughness PlasmaSpray) is a TPS surface (Figure 3). Someinorganic pollutions were detected: phosphorus (as phosphate), fluoride, and sulfur(as sulfate). The main characteristics of thiskind of surfaces are topographical: themicroroughness is maximal, it is smooth onthe nanoscale, and it is covered with manyextended cracks (related to the cooling ofthe plasma-sprayed titanium).Surfaces from the second groupThe second group gathers all the surfacesdesigned by subtraction using only blastingand/or etching.530Vol. XXXVII/No. Five/2011Osseospeed (Figure 4) is produced throughblasting with TiO2 particles and etching withhydrofluoric acid. The surface is impregnatedwith residual levels of fluoride. No pollution wasdetected. The microroughness is moderate; it iscovered with a nanoroughness all over theimplant. Some large TiO2 residual blastingparticles are impacted in the surface andpresent a very smooth surface. For this reason,the surface may be considered heterogeneous.Ankylos (Figure 5) is a blasted/etchedsurface. The surface is covered with aluminaparticles (Al2O3), and many other inorganicpollutions were detected—sodium, fluoride,calcium, phosphorus (as phosphate), zinc,chloride, and sulfur (as sulfate). The surface ismoderately microrough and nanosmooth,but it is quite heterogeneous all over theimplant.Zimmer MTX (Figure 6) is produced usingblasting with hydroxyapatite on a grade 5titanium core. Therefore, the surface isimpregnated with low levels of calciumphosphate (CaP); it is not visible with FESEM but is homogeneous all over thesurface. A significant silicon inorganic pollution was also detected. The microroughnessis minimal, and the surface is smooth on thenanoscale.Camlog Promote (Figure 7) is a blasted/etched surface. Some inorganic pollutionwith zinc and calcium was detected. Thesurface is moderately microrough and nanosmooth, and it is quite homogeneous allover the implant.BTI Interna (Figure 8) is an etched surfacecovered with high levels of organic carbonspecies (organic pollution). The surfaceshows numerous aggressive etching pits ina high magnification but with a low heightdeviation amplitude; thus, the surface has aglobal smooth aspect on the microscale. At ahigher magnification, the topography appears smooth on the nanoscale.EVL Plus (Figure 9) is a blasted/etchedsurface. It is impregnated with residual levels

Dohan Ehrenfest et alFIGURES 1 AND 2. FIGURE 1. Identification card of the TiUnite surface. FIGURE 2. Identification card of theOspol surface.Journal of Oral Implantology531

Identification Cards of 14 Implant SurfacesFIGURES 3 AND 4. FIGURE 3. Identification card of the Kohno HRPS surface. FIGURE 4. Identification card ofthe Osseospeed surface.532Vol. XXXVII/No. Five/2011

Dohan Ehrenfest et alFIGURES 5 AND 6. FIGURE 5. Identification card of the Ankylos surface. FIGURE 6. Identification card of theZimmer MTX surface.Journal of Oral Implantology533

Identification Cards of 14 Implant SurfacesFIGURES 7 AND 8. FIGURE 7. Identification card of the Camlog Promote surface. FIGURE 8. Identification cardof the BTI Interna surface.534Vol. XXXVII/No. Five/2011

Dohan Ehrenfest et alFIGURES 9 AND 10. FIGURE 9. Identification card of the EVL Plus surface. FIGURE 10. Identification card of theTwinkon Ref surface.Journal of Oral Implantology535

Identification Cards of 14 Implant Surfacesof calcium phosphate and covered withsmall alumina (Al2O3) particles. A residualfluoride inorganic pollution was also detected. The microroughness is minimal, and thesurface is smooth on the nanoscale.Twinkon Ref (Figure 10) is a blastedsurface on a grade 5 titanium core. Thesurface appears impregnated with calcium,and it is covered with alumina particles(Al2O3) and a thick organic pollution (thickcarbon overcoat all over the implant). Someother inorganic pollutions were detected:silicon, sulfur (as sulfate), chloride, and zinc.The surface is minimally microrough, isnanosmooth, and is heterogeneous all overthe implant.Surfaces from the third groupThe third group gathers the surfaces designed by subtraction using blasting and/oretching and postprocessing (except coating).In this study, only one product could beclassified in this group.Ossean (Figure 11) is a blasted/etchedsurface with unknown postprocessing. TheTiO2 layer is thicker than 12 nm. The surfaceis impregnated with low levels of calciumphosphate, which is not visible with FE-SEMbut is homogeneous all over the surface. Nopollution was detected. The microroughness isminimal, though close to the moderate level,and it is covered with a nanoroughness all overthe implant. The surface is homogeneous inchemistry and topography, and it may beconsidered fractal according to our definition.Surfaces from the fourth groupThe fourth group gathers the surfacespresenting a final chemical coating.Of these, 3I NanoTite (Figure 12) is anetched surface on a grade 5 titanium core;it has a final discontinuous coating with CaPparticles. Some traces of fluoride and sulfurinorganic pollutions were also detected. Themicroroughness is smooth and flat, and itis covered with nanoparticles that create a536Vol. XXXVII/No. Five/2011significant texture on the nanoscale. The sizeof the CaP particles can vary a lot, however,and many microparticles or CaP aggregatesare randomly found on the surface. For thisreason, the surface should be consideredheterogeneous.SLActive (Figure 13) is a blasted/etchedsurface with a final immersion in a sodiumchloride (NaCl) physiological solution. Thesurface is therefore coated with NaClcrystals, and some traces of other elementswere also detected (fluoride, potassium,calcium, and phosphate). The microtopography is moderately rough and rugged.When the implant is outside its box, thesolution dries quickly on the surface andcreates many NaCl aggregates all over theimplant and a significant nanotexturization.However, the morphology of this coating isvery heterogeneous.Integra-CP, previously known as BiconNanoTite (Figure 14), is a blasted/etchedsurface with a final coating using calciumphosphate ion-beam assisted deposition.The CaP coating is thicker than 100 nm,and CaP is therefore the core material of thissurface. Some traces of fluoride and sulfurpollutions were also detected. The surface isflat on the microscale and smooth on thenanoscale.DISCUSSIONSince the osseointegration concept wasestablished, the characteristics of the bone/implant interface and ways to improve ithave been analyzed in dental implantresearch. However, the accurate characterization of the surfaces is still a source ofmisunderstanding and debate.The use of these classic instruments forchemical analysis (XPS/ESCA and AES) seemsto be a simple and logical approach, butmost studies about implant surface stillneglect the investigation of the surfacechemistry.2 The chemical characterization of

Dohan Ehrenfest et alFIGURES 11 AND 12. FIGURE 11. Identification card of the Ossean surface. FIGURE 12. Identification card of the3I NanoTite surface.Journal of Oral Implantology537

Identification Cards of 14 Implant SurfacesFIGURES 13 AND 14. FIGURE 13. Identification card of the SLActive surface. FIGURE 14. Identification card ofthe Integra-CP/NanoTite surface.538Vol. XXXVII/No. Five/2011

Dohan Ehrenfest et alcommercially available products is also quitescarce in the literature.34,35 In contrast, theevaluation of the surface morphology andtopography on the micrometer scale iscommonly used, but the way to quantifythe microstructures remains a source ofdebate, particularly because data are verydependent on the instrument and protocolused.36 Finally, the investigation of thenanotopography of dental implants is a veryrecent approach.37–39The concept of these ID cards is to gatherthe main information concerning a surface ina simple and standardized way. However, it isvery important to understand the limitationsof such a system. The chemical analyses areaccurate but are always difficult to interpretcompletely without detailed spectrometricgraphs and the knowledge of how to readthem.35 The IFM mean values of the microtopography also have to be considered asrelative, because such values are alwaysdependent on the method used (measuringequipment, filtering technique, number andsize of measure areas).36 Finally, the notionsof nanosmooth/nanorough are only qualitative and morphological and, like most otherterms used in the codification system, arebased on the definitions given in the classification article.2 Other authors may prefer touse different terms or interpretations.38 This iswhy the codes are called ‘‘DEC’’: the datahere are sorted and interpreted following aspecific and well-defined system, and somedifferences can appear in the terminologyused by other authors. Therefore, the IDcards and the DEC system must be considered as a tool, not as absolute data. Whenconsidering all of these codes obtained bythe same protocol, it is possible to comparethe main characteristics of the variousimplant surfaces together.The notion of surface homogeneity isalso to be understood with caution. Even ifdental implants are supposed to be carefullymanufactured products, most implants arenot as homogeneous as expected, thoughthis is considered as normal. Therefore, in thecodification system, the homogeneity of asurface should be understood as a relativehomogeneity, that is, implants are all homogeneous unless they are clearly heterogeneous. The reasons for this heterogeneity arenumerous but always quite simple to understand: when some areas of the surface arelacking a key characteristic of the other areas(eg, Osseospeed smooth TiO2 blasting residues), when the crystal clusters cannot becontrolled (eg, SLActive, NanoTite), or whenthe surfaces are covered by various kinds ofpollutions (eg, Ankylos, Tekka). In this classification system, it remains a qualitativeparameter, not a quantitative one.The first objective of the DEC2 system wasto create a standard procedure for thecharacterization of surfaces in order to defineand isolate more clearly the chemical andphysical parameters when comparing thebiological performances of various surfaces.It was therefore first an experimental tool.The second objective of the DEC systemis directly related to the development ofthe surface ID card: to create a standardprocedure for describing and controllingcommercially available products. Nowadays,there is no serious standard that defineswhat a surface should be, and dentalimplants are marketed without a cleardefinition of their surface characteristics. Thislack of surface characterization is commonto many implantable biomedical devices.Therefore, the practitioner has no realinformation about the material that isimplanted in his or her patients, thoughthe practitioner is partially responsible forthese implanted materials. This situation iscontradictory, and may be legally dangerous, when considering that the surfacedesign defines the interface of the biomaterial with the host tissues and thusrepresents a key component of the implantbiocompatibility.Journal of Oral Implantology539

Identification Cards of 14 Implant SurfacesThe use of the DEC system on a productID card that gathers the main surface data isa simple way to provide this key informationto practitioners. However, these analysesand the establishment of these ID cardsshould always be performed by independent teams without conflict of interest andshould be repeated frequently within thevarious references and batches of thecompany’s production to guarantee thevalidity of the codes. The DEC system could,therefore, be a first step toward the development of an ISO characterization standardprocedure in order to increase the control ofthe available products. This is of particularinterest because the globalization of implantproduction means

Identification Card and Codification of the Chemical and Morphological Characteristics of 14 Dental Implant Surfaces David M. Dohan Ehrenfest, DDS, MS, PhD1* Lydia Vazquez, MD, DDS2 Yeong-Joon Park, DDS, PhD3 Gilberto Sammartino, MD, DDS4 Jean-Pierre Bernard, MD, PhD2 Dental implants are commonly use