coelho 2010 mbobm surface dogs

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Research paper

Biomechanical and histomorphometric analysis of etchedand non-etched resorbable blasting media processed implantsurfaces: An experimental study in dogs

Charles Marina, Rodrigo Granatob, Marcelo Suzukic, Malvin N. Janald, Jose N. Gilb,Carlos Nemcovskye, Estevam A. Bonfante f, Paulo G. Coelho f,∗

aDepartment of Oral and Maxillofacial Surgery, Pontificia Universidade Catolica do Rio Grande do Sul, Av. Ipiranga 6681, Prédio 6, PortoAlegre - RS, 90610-001, BrazilbDepartment of Dentistry, Oral and Maxillofacial Surgery, Universidade Federal de Santa Catarina, Trindade 88040-900, Florianopolis, SC,BrazilcDepartment of Prosthodontics, Tufts University School of Dental Medicine, 1 Kneeland Street, 02111, Boston, MA, USAdDepartment of Epidemiology and Health Promotion, New York University, 345 E 24th Street, 10010, New York, NY, USAeDepartment of Periodontology, Tel Aviv University, Ramat Aviv 69978, Dental Clinic building, Tel Aviv, IsraelfDepartment of Biomaterials and Biomimetics, New York University, 345 E 24th Street, 10010, New York, NY, USA

A R T I C L E I N F O

Article history:

Received 13 December 2009

Received in revised form

4 February 2010

Accepted 11 February 2010

Published online 26 February 2010

Keywords:

Dental implant

Surface

Resorbable blasting media

Characterization

In vivo

A B S T R A C T

This study characterized the interplay between topography/chemistry and early bone

response of etched and no-etched resorbable blasted media (RBM) processed surfaces.

Screw-root form Ti–6Al–4V implants treated with alumina blasting/acid-etching (AB/AE),

RBM alone (RBM), and RBM + acid-etching (RBMa) were evaluated. The surface was

characterized by scanning electron microscopy, atomic force microscopy, and X-ray

photoelectron spectroscopy. Implants placed in the tibia of dogs remained 3 and 5 weeks

in vivo. Following euthanasia, half of the specimens were torqued to interface failure and

the remaining subjected to bone-to-implant contact (BIC) and bone area fraction occupied

(BAFO) between threads evaluation. The AB/AE surface was rougher than the RBM and

RBMa. Higher levels of calcium and phosphorous were observed for the RBM surface

compared to the RBMa. No significant differences were observed in torque, BIC, and BAFO

between surfaces. Woven bone formation at 3 weeks and its initial replacement by lamellar

bone at 5 weeks were observed around all implants’ surfaces.c© 2010 Elsevier Ltd. All rights reserved.

t

o

d

∗ Corresponding address: Department of Biomaterials and BiomimeYork, NY, USA. Tel.: +1 646 8121893; fax: +1 212 995 4244.

E-mail addresses: [email protected] (C. Marin), granatobu(M. Suzuki), [email protected] (M.N. Janal), [email protected] (J.N. Gil), carl(E.A. Bonfante), [email protected] (P.G. Coelho).

1751-6161/$ - see front matter c© 2010 Elsevier Ltd. All rights reservedoi:10.1016/j.jmbbm.2010.02.002

ics, New York University, 345 E 24th Street, 10010, room 314a, New

[email protected] (R. Granato), [email protected]@post.tau.ac.il (C. Nemcovsky), [email protected]

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http://dx.doi.org/10.1016/j.jmbbm.2010.02.002

J O U R N A L O F T H E M E C H A N I C A L B E H AV I O R O F B I O M E D I C A L M A T E R I A L S 3 ( 2 0 1 0 ) 3 8 2 – 3 9 1 383

1. Introduction

Following implant placement, the establishment and main-tenance of contact between bone and endosseous implantsis usually observed, making implant dentistry one of themost successful treatment modalities in the medical field.Despite its high success rates, often exceeding 90% over morethan 10 years (Albrektsson and Sennerby, 1991; Branemarket al., 1977; Schnitman et al., 1997), implant design has beenconstantly investigated in an attempt to improve shortand long-term host-to-implant interactions (Albrektsson andWennerberg, 2004a,b; Coelho et al., 2009b; Granato et al.,2009).

Investigations have shown that the interplay betweenimplant geometry and initial interaction with its respectiveosteotomy dimensions result in distinct initial bone healingpatterns, however, the long-term bone morphology is alsoaffected by implant geometry (Berglundh et al., 2003; Coelhoet al., 2009d), therefore, surface modifications have been byfar the most investigated implant design aspect (Albrektssonand Wennerberg, 2004a; Coelho et al., 2009b).

Over the years, several investigations have demonstratedincreased biological response and bone mechanical proper-ties for textured (rough) endosteal implant surfaces comparedto as-turned (as-machined) surfaces (Abrahamsson et al.,2004; Grizon et al., 2002). The fabrication of textured surfaceshas been achieved through a variety of methods includingacid-etching (Butz et al., 2006; Klokkevold et al., 1997), an-odization (Huang et al., 2005; Jungner et al., 2005; Xiropaidiset al., 2005), grit blasting with alumina (Suzuki et al., 2009),silica (Albrektsson and Wennerberg, 2004b; Buser et al., 2004),titanium oxide (Vercaigne et al., 2000), or resorbable blast-ing media (RBM) (bioactive/biocompatible ceramics) (Coelhoand Lemons, 2009; Granato et al., 2009; Marin et al., 2008),and such surfaces (rough surfaces with arithmetic average ofabsolute values (Sa) between 0.5 and 2 µm (Albrektsson andWennerberg, 2004a; Coelho et al., 2009b) have been commer-cially available for over a decade with acceptable long-termsuccess.

While increases in surface roughness have improvedthe early host-to-implant response, the incorporation ofcalcium- and phosphorous-based (CaP) bioactive ceramicplasma sprayed coating (such as plasma sprayed hydroxya-patite, PSHA) on implant surfaces have resulted in highly os-seoconductive and biocompatible properties (Kay, 1992; Kimet al., 2005; Lacefield, 1988). However, the presence of a weaklink between the PSHA coating and the metallic substratealong with the process-inherent compositional variation hasresulted in substantial decreases in PSHA coated implantsutilization (Lacefield, 1988, 1998).

In an attempt to benefit from the osseoconductive prop-erties of calcium-phosphates while avoiding the process-inherent drawbacks of PSHA coatings, the incorporation ofreduced scale CaP on implant surfaces has been achievedthrough a variety of techniques, such as: ion beam assisteddeposition (IBAD) (Granato et al., 2009; Suzuki et al., 2009),sputtering (Yang et al., 2005), discrete crystalline deposition(Davies, 2007; Mendes et al., 2007), through the RBM processes(Marin et al., 2008), and others (Meirelles et al., 2008a,b).Specific to the CaP incorporation through the RBM process,

the surface texture and chemistry (especially the amount ofCaP) are dependent on several variables such as blasting me-dia composition, particle size, and processing parameters likeblasting pressure and distance, and subsequent acid-etchingtreatments (Coelho et al., 2009b). Due to these differences, itis unknown if any attempt for further treatment followinginitial blasting with bioactive ceramic (which decreases theamount of available CaP) could potentially have an influencein the early host-to-implant response.

The purpose of this investigation was to biomechanicallyand histomorphometrically evaluate etched and non-etchedRBM processed surfaces.

2. Materials and methods

2.1. Implant surfaces and characterization

This study utilized screw-root form endosseous Ti–6Al–4Vimplants of 3.75 mm in diameter by 10 mm in length (Seven,MIS, Shlomi, Israel) (n = 81). The implant groups utilizedincluded the following surfaces: alumina blasting/acid-etching (AB/AE, used as control), RBM blasting (RBM), and RBMblasting + acid-etching (RBMa).

The AB/AE surface treatment was achieved by surfaceblasting with large particles (size ∼300–400 microns) of Al2O3followed by etching with hydrochloric/sulfuric acid. TheRBM surfaces were achieved by blasting with HA/TCP (20/80percent ratio) particles∼200–400micronswithout subsequentacid-etching. The RBMa surfaces were achieved by the sameprocess as RBM surface followed by cleaning with HNO3 atroom temperature for 10 min.

Nine implants (n = 3 each group) were used for surfacetopography assessment by scanning electron microscopy(SEM) and atomic force microscopy (AFM). SEM (Philips XL30, Eindhoven, The Netherlands) was performed at variousmagnifications under an acceleration voltage of 15 kV.Surface three-dimensional (3D) imaging was collected byAFM (Nanoscope IIIa Multimode system, Digital Instruments,Santa Barbara, CA, USA) in contact mode. A scanner with amaximum 125 µm horizontal and 5 µm vertical range and a200 µm Si3N4 cantilever tip using a constant force of 0.12 N/mwas used. The region analyzed was the flat part of the implantcutting edges, and 10×10 µm scan areas were used (Meirelleset al., 2008a,b). Three scans per implant were performed andSa (arithmetic average high deviation) and Sq (root meansquare) parameters determined. Following data normalityverification, statistical analysis at 95% level of significancewas performed by one-way ANOVA.

Surface specific chemical assessment was performed byX-ray photoelectron spectroscopy (XPS). The implants wereinserted in a vacuum transfer chamber and degassing it to10−7 torr. The samples were then transferred under vacuumto a Kratos Axis 165 multitechnique XPS spectrometer (KratosAnalytical Inc., Chestnut Ridge, NY, USA). Survey and high-resolution spectra were obtained using a 165mmmean radiusconcentric hemispherical analyzer operated at constant passenergy of 160 eV for survey and 80 eV for high resolutionscans. The take off angle was 90◦ and a spot size of 150 µm×150 µm was used. The implant surfaces were evaluated atvarious locations.

384 J O U R N A L O F T H E M E C H A N I C A L B E H AV I O R O F B I O M E D I C A L M A T E R I A L S 3 ( 2 0 1 0 ) 3 8 2 – 3 9 1

2.2. Animal model

For the animal model, 24 implants of each of the 3 surfaceswere utilized. The study comprised of 12 adult male beaglesdogs with ∼1.5 years of age. The protocol received theapproval of the Ethics Committee for Animal Research atUniversidade Federal de Santa Catarina- Brazil.

Prior to general anesthesia, IM atropine sulfate (0.044mg/kg) and xilazine chlorate (8 mg/kg) were administered. A15 mg/kg ketamine chlorate dose was then utilized to achievegeneral anesthesia.

The proximal medial tibia on right side was initiallyshaved with a razor blade and followed by the applicationof antiseptic iodine solution. An incision through the skin of∼5 cm in length was utilized for access to the periosteum,which was elevated for bone exposure.

Standardized osteotomies were made with sequentialdrills (pilot drill, followed by 2 mm, 2.5 mm, 3.0 mm, 3.5 mm)at 1.200 rpm under abundant saline irrigation. The first im-plant was inserted 2 cm below the joint capsule line at thecentral antero-medial position of the proximal tibiae (proce-dures were performed bilaterally). The other two devices wereplaced along the distal direction at distances of 1 cm fromeach other along the central region of the bone. The order inwhich the implants with different surfaces were placed wasdifferent in each site. Balanced surgical procedures were uti-lized in order to allow the comparison of the torque and his-tology of same number of implant surfaces per time in vivo,surgical site (1 through 3), and animal per time in vivo.

Following implant placement, a healing cap was attachedto each implant internal connector to avoid tissue over-growth. The soft tissue was sutured in layers following stan-dard procedures, where the periosteum was sutured withvicryl 4-0 (Ethicon Johnson, Miami, FL, USA) and the skin with4-0 nylon (Ethicon Johnson, Miami, FL, USA).

Post-operative antibiotic and anti-inflammatory medica-tion included a single dose of Benzyl Penicillin Benzathine(20.000 UI/kg) IM and Ketoprofen 1% (1 ml/5 kg). The animalswere euthanized after post-surgical periods of 3 (n = 6) and 5(n = 6) weeks by anesthesia overdose. At necropsy, the tibiaewere retrieved by sharp dissection and surgical blades wereused for soft tissue removal. Half of the specimens servedfor mechanical testing (left limbs) and the other half wereprocessed for nondecalcified histomorphologic and histomor-phometric evaluation (right limbs).

For the torque testing, the tibia was adapted to anelectronic torque machine equipped with a 2000 N cm torqueload cell (Test Resources, Minneapolis, MN, USA). Custommachined tooling was adapted to each implant internalconnection and the bone block was carefully positioned toavoid specimen misalignment during testing. The implantswere torqued in the counter clockwise direction at a rate of∼0.196 rad/min, and a torque versus displacement curve wasrecorded for each specimen.

The histology group samples were reduced to blocks con-taining the implants and surrounding bone, and were im-mersed in 10% buffered formalin solution for 24 h. The blockswere then washed in running water for 24 h, and gradu-ally dehydrated in a series of alcohol solutions ranging from70%–100% ethanol. Following dehydration, the samples were

embedded in a methacrylate-based resin (Technovit 9100,Heraeus Kulzer GmbH, Wehrheim, Germany) according to themanufacturer’s instructions. The blocks were cut into slices(∼300 µm thickness) aiming the center of the implant alongits long axis with a precision diamond saw (Isomet 2000,Buehler Ltd., Lake Bluff, IL, USA), glued to acrylic plates withan acrylate-based cement, and a 24 h setting time was al-lowed prior to grinding and polishing. The sections were thenreduced to a final thickness of ∼30 µm by means of a se-ries of SiC abrasive papers (400, 600, 800, 1200 and 2400)(Buehler Ltd., Lake Bluff, IL, USA) in a grinding/polishingmachine (Metaserv 3000, Buehler Ltd., Lake Bluff, IL, USA)under water irrigation (Donath and Breuner, 1982). The sec-tions were then stained by toluidine blue and histomorpho-logically evaluated with optical microscopy.

The bone-to-implant contact (BIC) was determined at50X–200X magnification (Leica DM2500M, Leica MicrosystemsGmbH, Wetzlar, Germany) by means of computer software(Leica Application Suite, Leica Microsystems GmbH, Wetzlar,Germany). The regions of bone-to-implant contact along theimplant perimeter were subtracted from the total implantperimeter, and calculations were performed to determinethe BIC. The bone area fraction occupied (BAFO) betweenthreads in trabecular bone regions was determined at100X magnification (Leica DM2500M, Leica MicrosystemsGmbH, Wetzlar, Germany) by means of a computer software(Leica Application Suite, Leica Microsystems GmbH, Wetzlar,Germany). The areas occupied by bone were subtractedfrom the total area between threads, and calculations wereperformed to determine the BAFO (reported in percentagevalues of bone area fraction occupied) (Leonard et al., 2009).

Preliminary statistical analyses showed no effect ofimplant site (i.e., there were no consistent effects of positions1 to 3 along the tibia) on all measurements. Therefore, sitewas not considered further in the analysis. Further statisticalevaluation of Torque, BIC, and BAFO measures employed amixed-model (split-plot) ANOVA with one within-subjectsfactor (2 levels of time in vivo) and one between subjectsfactor (6 levels of implant surfaces). Statistical significancewas indicated by p-levels less than 5%, and post-hoc testingemployed the Fisher LSD test.

3. Results

The implant surfaces’ electron micrographs and 3D atomicforce microscopies are presented in Fig. 1. The AB/AEpresented a textured surface without the presence ofembedded alumina particles while the RBM surface presentedmultiple areas covered with embedded blasting media and asmoother texture profile (Fig. 1). The RBMa surface electronmicrographs showed that the acid-etching procedure waseffective on removing embedded blasting media particles,revealing a textured surface.

The AFM assessment showed that the AB/AE surfacepresented significantly higher higher Sa (p < 0.02) and Sq (p <

0.001) values compared to the RBM surface (Fig. 2), whereasthe RBMa surface presented intermediate values. From aqualitative and quantitative perspective, the AB/AE presented


a

b

c

20um

20um

20um

Fig. 1 – SEM and AFM imaging (10 µm × 10 µm) for the (a) AB/AE surface, (b) RBM, and (c) RBMa groups (color on the Webonly).

Fig. 2 – Measurable roughness parameters (Sa and Sq) forthe three implant surfaces. The roughest profile wasobserved for the AB/AE group, and was followed by theRBMa and RBM surfaces, respectively (color on the Webonly).

higher submicrometer texturing (Figs. 1 and 2) compared toboth RBM treated surfaces.

The XPS spectra for the different surfaces and theirrespective atomic concentrations are presented in Fig. 3.The AB/AE XPS survey analysis showed peaks of Ti, Al, V,C, and O (Fig. 3a), while the RBM and RBMa presented Ti,Al, Ca, C, P, N (Fig. 3b and c). High-resolution spectrumevaluation showed that for all surfaces titanium was foundprimarily as TiO2 with a very low level of metallic Ti, andcarbon was observed primarily as hydrocarbon (C–C, C–H)with lower levels of oxidized carbon forms. For both the RBMand RBMa groups, calcium and phosphate were detected invaried atomic concentrations. For the RBM group, calciumand phosphate atomic concentrations ranged from ∼13.5 to∼22 and ∼8 to ∼16 at.%, respectively. Substantially loweramounts of calcium and phosphate were observed for theRBMa surface, where atomic concentrations ranged from ∼1to ∼3.5 and ∼1 to ∼2 at.%, respectively.

The animal surgical procedures and follow-up demon-strated no complications regarding procedural conditions,postoperative infection, or other clinical concerns.

The biomechanical testing results showed that time invivo and implant surface did not have a significant effecton torque to interface fracture (p > 0.29 and p = 0.16,respectively) (Table 1). No interaction between time in vivoand implant surface was found (p > 0.62).


a

b

c

Fig. 3 – XPS spectrum and associated surface composition for (a) AB/AE, (b) RBM, and (c) RBMa surface groups (color on theWeb only).


Table 1 – GLM ANOVA summary for torque to interfacefracture as a function of surface and time in vivo. Timein vivo and implant surface did not result in significanteffects in torque to interface fracture.

Source Numeratordf

Denominatordf

F Sig.

Intercept 1 5 587.004 0.000Time 1 25 1.139 0.296Surface 2 25 1.973 0.160Time ∗ Surface 2 25 0.480 0.624

Time Surface Count Mean Standarddeviation

Coefficient ofvariation (%)

3 AB/AE 6 89.2667 20.22322 22.7RBM 6 104.9500 14.07320 13.4RBMa 6 96.9500 22.31383 23.0Total 18 97.0556 19.19360 19.8


Fig. 4 – General observation of the interaction betweenimplant and bone depicted intimate contact betweenimplant and bone at cortical and trabecular regions (coloron the Web only).

Qualitative evaluation of the toluidine blue stained thinsections showed intimate contact between cortical andtrabecular bone (Fig. 4) for all implant surfaces. At 3 weeks,newly formed woven bone was observed in close proximitywith all implant surfaces (Fig. 5). The same bone morphologicevolution occurred around all surfaces, where lamellar bone

Table 2 – GLM ANOVA summary for BIC as a function ofsurface and time in vivo. Time in vivo and implantsurface did not result in significant effects in BIC.

Source Numeratordf

Denominatordf

F Sig.

Intercept 1 30 3115.611 0.000Time 1 30 0.069 0.795Surface 2 30 1.811 0.181Time ∗ surface 2 30 1.984 0.155





Table 3 – GLM ANOVA summary for BAFO as a functionof surface and time in vivo. Time in vivo and implantsurface did not result in significant effects in BAFO.

Source Numeratordf

Denominatordf

F Sig.

Intercept 1 30 853.407 0.000Time 1 30 3.924 0.057Surface 2 30 0.073 0.930Time ∗ surface 2 30 1.490 0.241





replacing the woven bone present at 3 weeks in vivo wasobserved (Fig. 5).

The histomorphometric results demonstrated that timein vivo and implant surface also did not have a significanteffect on BIC (p > 0.79, and p > 0.18, respectively, Table 2).However, while implant surface did not have an effect inBAFO (p > 0.93), a substantial increase was observed between3 and 5 weeks implantation time (p = 0.057), although notstatistically significant (Table 3). No statistical significance forthe surface and time in vivo interaction was observed for BICand BAFO (p > 0.15, and p > 0.24, respectively).

4. Discussion

To date, implant surfaces have evolved from the smooth as-machined (as-turned) surfaces towards the now consideredstandard rough surfaces that are fabricated by a variety


a b

c d

e f

Fig. 5 – Optical micrographs showed newly formed woven bone in close proximity with all three implant surfaces (a)AB/AE, (c) RBM, (e) RBMa at 3 weeks. At 5 weeks, initial replacement of woven bone by lamellar bone (lightly stained bonebetween threads) was observed for all the (b) AB/AE, (d) RBM, (f) RBMa groups (color on the Web only).

of methods (Coelho et al., 2009b). Several studies havedemonstrated enhanced host-to-implant response (includingbone mechanical properties) for rough surfaces compared tosmooth surfaces (Albrektsson and Wennerberg, 2004a; Butzet al., 2006; Grizon et al., 2002; Wennerberg et al., 1997). In themeantime, incorporation of bioactive ceramic coatings hasshown high biocompatible and osseoconductive properties(higher than rough surfaces) early after implantation (Cheang

and Khor, 1996; de Bruijn et al., 1994; deGroot et al., 1990;Ong et al., 2004; Yang et al., 1997). However, due to processinherent properties and their potential clinical drawbacks,the utilization of bioactive coatings (primarily PSHA) hasbeen drastically reduced and has led to bioactive ceramicincorporation in reduced length scales through a variety ofmethods (Davies, 2007; Granato et al., 2009; Marin et al., 2008;Suzuki et al., 2009).


Recent research has shown promising results concerningreduced length scale bioactive ceramic incorporation onimplant surfaces (Coelho et al., 2009a; Granato et al.,2009; Marin et al., 2008; Meirelles et al., 2008a,b; Suzukiet al., 2009). However, due to variations in their physicalform, distribution and chemical properties, little has beenestablished regarding the amount and form of Ca–P thatresults in the highest host-to-implant response (Lemons,2004). Mendes et al. (2007) have demonstrated higherbiological response for a discrete crystalline deposition ofhydroxyapatite over a dual acid-etched surface. Regardingnanothickness coatings, a substantial body of literature hasshown higher biomechanical fixation (Coelho et al., 2009a;Granato et al., 2009) and BIC levels (Meirelles et al., 2008a,b).Incorporation of Ca and P at the surface and within thesurface oxide layer through variations in the RBMmethod hasalso resulted in early healing enhancements versus dual acid-etched surfaces in investigations concerning human (Shibliet al., 2009) and animal (Marin et al., 2008) subjects. Thus,even though the body of literature in the topic has beenincreasing, no informed design rationale with respect to theform and amount of CaP surface incorporation is available forimplant designing (Lemons, 2004).

The present study evaluated the two ends of the scaleconcerning the amount of CaP incorporated in implantsurfaces through the RBM method utilizing an HA/TCP(20/80) blasting media with and without post-blasting etchingversus an AB/AE surface. The XPS results showed that thesubsequent acid treatment given to the RBMa resulted in adrastic decrease (an order of magnitude) in the amount of Caand P available in the as-blasted RBM surface. The XPS resultsare in agreement with the electron micrographs and three-dimensional profiles obtained through AFM, where smootherprofiles were observed for the RBM surface compared to theRBMa surface. Such smoother profile was due to particleembedding at the RBM group implant surface, which wasselectively removed following acid treatment resulting in theRBMa group. The rougher profile observed for the AB/AEsurface was due to the harder blasting media utilizedfor surface texturing. From a micrometric surface texturestandpoint, all surfaces utilized in the present study can beconsidered textured as most commercially available implantsurfaces (Albrektsson and Wennerberg, 2004a,b; Albrektssonet al., 2008). However, from a basic science perspective, thesurfaces considered in the present study are consideredsubstantially rougher and do not fall within the nanometerscale surfaces investigated through interferometry along withAFM methods (Meirelles et al., 2007, 2008a,b). Thus, eventhough deeper insight could be obtained by evaluation ofdifferent roughness parameters and methods at differentimplant regions (Meirelles et al., 2007, 2008a,b), the variationin surface chemistry within surfaces and the lack ofdifference in the in vivo measured parameters would notallow proper roughness structure and property.

The general results from the histologic sections showedthat all the three surfaces investigated were biocompatibleand osseoconductive, presenting bone in close contact withthe implant surface at regions of cortical and trabecularbone. From a morphologic standpoint, woven bone wasobserved around all surfaces at 3 weeks. At 5 weeks, initial

replacement of woven bone by lamellar bone was observedfor all surfaces. No detrimental effect due to the surfaceinhomogeneous composition was observed for the RBM groupat both implantation times.

In tandem with the histomorphologic parameters, no sig-nificant differences were observed between the BIC and BAFOosseointegration measurable parameters along with no dif-ferences in torque to interface failure. The histomorphomet-ric results showed that high degrees of BIC were establishedfor all surfaces until 3 weeks in vivo, and that these val-ues were maintained up to five weeks, and these observa-tions are in agreement to previous studies using Ca- andP- based surfaces (Granato et al., 2009; Marin et al., 2008).On the other hand, a substantial increase in BAFO was ob-served over experimentation time, demonstrating that from 3to 5 weeks subsequent bone deposition took place along withan increase in bone degree of organization (lamellar bone for-mation) around all implant surfaces (Berglundh et al., 2003).Finally, no differences in torque was observed between sur-faces at both implantation times, demonstrating that afterinitial bone modeling resulting in woven bone formation, nosubsequent improvement in biomechanical fixation occurreddespite the initial remodeling observed at 5 weeks evidencedby partial woven bone replacement by lamellar bone.

5. Conclusion

Based on the results observed in our investigation, it ispossible to conclude that all surfaces were biocompatibleand osseoconductive, and subsequent treatment followingbioceramic coating was not detrimental or beneficial to earlyimplant-to-host interaction.

Acknowledgements

This work was partially funded by the Department of Oraland Maxillofacial Surgery at Universidade Federal de SantaCatarina. The implants were donated by MIS Implants,Shlomi, Israel. The authors also acknowledge Dr. Mary K.Cowman (NYU-Poly) for support.

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