Evaluation of nano-technology-modified zirconia oral implants: a study in rabbits

Objective: The objective of this study was to screen candidate nano‐technology‐modified, micro‐structured zirconia implant surfaces relative to local bone formation and osseointegration. Materials and Methods: Proprietary nano‐technology surface‐modified (calcium phosphate: CaP) micro‐structured zir...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Journal of clinical periodontology 2009-07, Vol.36 (7), p.610-617
Hauptverfasser: Lee, Jaebum, Sieweke, Janet H., Rodriguez, Nancy A., Schüpbach, Peter, Lindström, Håkan, Susin, Cristiano, Wikesjö, Ulf M. E.
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
container_end_page 617
container_issue 7
container_start_page 610
container_title Journal of clinical periodontology
container_volume 36
creator Lee, Jaebum
Sieweke, Janet H.
Rodriguez, Nancy A.
Schüpbach, Peter
Lindström, Håkan
Susin, Cristiano
Wikesjö, Ulf M. E.
description Objective: The objective of this study was to screen candidate nano‐technology‐modified, micro‐structured zirconia implant surfaces relative to local bone formation and osseointegration. Materials and Methods: Proprietary nano‐technology surface‐modified (calcium phosphate: CaP) micro‐structured zirconia implants (A and C), control micro‐structured zirconia implants (ZiUnite™), and titanium porous oxide implants (TiUnite™) were implanted into the femoral condyle in 40 adult male New Zealand White rabbits. Each animal received one implant in each hind leg; thus, 20 animals received A and C implants and 20 animals received ZiUnite™ and TiUnite™ implants in contralateral hind legs. Ten animals/group were euthanized at weeks 3 and 6 when biopsies of the implant sites were processed for histometric analysis using digital photomicrographs produced using backscatter scanning electron microscopy. Results: The TiUnite™ surface demonstrated significantly greater bone–implant contact (BIC) (77.6±2.6%) compared with the A (64.6±3.6%) and C (62.2±3.1%) surfaces at 3 weeks (p0.05). Similarly, there were non‐significant differences between the TiUnite™ and the ZiUnite™ surfaces (p>0.05). At 6 weeks, there were no significant differences in BIC between the TiUnite™ (67.1±4.2%), ZiUnite™ (69.7±5.7%), A (68.6±1.9%), and C (64.5±4.1%) surfaces (p>0.05). Conclusion: TiUnite™ and ZiUnite™ implant surfaces exhibit high levels of osseointegration that, in this model, confirm their advanced osteoconductive properties. Addition of CaP nano‐technology to the ZiUnite™ surface does not enhance the already advanced osteoconductivity displayed by the TiUnite™ and ZiUnite™ implant surfaces.
doi_str_mv 10.1111/j.1600-051X.2009.01423.x
format Article
fullrecord <record><control><sourceid>proquest_cross</sourceid><recordid>TN_cdi_proquest_miscellaneous_67403937</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><sourcerecordid>20685935</sourcerecordid><originalsourceid>FETCH-LOGICAL-c5833-9ec823c44ebdb4da4d5816f2089e3bdc3f3cd9c1d2b122672e33bf5fde80d98f3</originalsourceid><addsrcrecordid>eNqNkE1v1DAQhi1ERbeFv4B8gVuC7YmTmAMSWi3bVlUBCQQ3y_EHeEnixU7aXX49CbtajjAXj-Rn3hk9CGFKcjrVq01OS0IywunXnBEickILBvnuEVqcPh6jBQECWSkqcY4uUtoQQisAeILOqeBQA_AF-ri6V-2oBh96HBzuVR-ywervfWjDt33WBeOdtwb_8lGH3iscomqx77at6of0GiuchtHsse9xVE3jh_QUnTnVJvvs-F6iz-9Wn5ZX2e379fXy7W2m-bQ6E1bXDHRR2MY0hVGF4TUtHSO1sNAYDQ60EZoa1lDGyopZgMZxZ2xNjKgdXKKXh9xtDD9HmwbZ-aRtOx1mw5hkWRUEBFT_BBkpay6AT2B9AHUMKUXr5Db6TsW9pETO3uVGznrlrFfO3uUf73I3jT4_7hibzpq_g0fRE_DiCKikVeui6rVPJ47Rkhackol7c-AefGv3_32AvFl-WM3tFJAdAnwa7O4UoOKPyQhUXH65W8v1TV0tiysq1_AbFfKuPQ</addsrcrecordid><sourcetype>Aggregation Database</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype><pqid>20685935</pqid></control><display><type>article</type><title>Evaluation of nano-technology-modified zirconia oral implants: a study in rabbits</title><source>MEDLINE</source><source>Wiley Online Library Journals Frontfile Complete</source><creator>Lee, Jaebum ; Sieweke, Janet H. ; Rodriguez, Nancy A. ; Schüpbach, Peter ; Lindström, Håkan ; Susin, Cristiano ; Wikesjö, Ulf M. E.</creator><creatorcontrib>Lee, Jaebum ; Sieweke, Janet H. ; Rodriguez, Nancy A. ; Schüpbach, Peter ; Lindström, Håkan ; Susin, Cristiano ; Wikesjö, Ulf M. E.</creatorcontrib><description>Objective: The objective of this study was to screen candidate nano‐technology‐modified, micro‐structured zirconia implant surfaces relative to local bone formation and osseointegration. Materials and Methods: Proprietary nano‐technology surface‐modified (calcium phosphate: CaP) micro‐structured zirconia implants (A and C), control micro‐structured zirconia implants (ZiUnite™), and titanium porous oxide implants (TiUnite™) were implanted into the femoral condyle in 40 adult male New Zealand White rabbits. Each animal received one implant in each hind leg; thus, 20 animals received A and C implants and 20 animals received ZiUnite™ and TiUnite™ implants in contralateral hind legs. Ten animals/group were euthanized at weeks 3 and 6 when biopsies of the implant sites were processed for histometric analysis using digital photomicrographs produced using backscatter scanning electron microscopy. Results: The TiUnite™ surface demonstrated significantly greater bone–implant contact (BIC) (77.6±2.6%) compared with the A (64.6±3.6%) and C (62.2±3.1%) surfaces at 3 weeks (p&lt;0.05). Numerical differences between ZiUnite™ (70.5±3.1%) and A and C surfaces did not reach statistical significance (p&gt;0.05). Similarly, there were non‐significant differences between the TiUnite™ and the ZiUnite™ surfaces (p&gt;0.05). At 6 weeks, there were no significant differences in BIC between the TiUnite™ (67.1±4.2%), ZiUnite™ (69.7±5.7%), A (68.6±1.9%), and C (64.5±4.1%) surfaces (p&gt;0.05). Conclusion: TiUnite™ and ZiUnite™ implant surfaces exhibit high levels of osseointegration that, in this model, confirm their advanced osteoconductive properties. Addition of CaP nano‐technology to the ZiUnite™ surface does not enhance the already advanced osteoconductivity displayed by the TiUnite™ and ZiUnite™ implant surfaces.</description><identifier>ISSN: 0303-6979</identifier><identifier>EISSN: 1600-051X</identifier><identifier>DOI: 10.1111/j.1600-051X.2009.01423.x</identifier><identifier>PMID: 19538335</identifier><language>eng</language><publisher>Oxford, UK: Blackwell Publishing Ltd</publisher><subject>Animals ; backscatter scanning electron microscopy ; Biological and medical sciences ; bone density ; Bone Regeneration - drug effects ; Bone Regeneration - physiology ; bone-implant contact ; calcium phosphate ; Calcium Phosphates - chemistry ; Coated Materials, Biocompatible - chemistry ; Coated Materials, Biocompatible - pharmacology ; Dental Implantation, Endosseous - instrumentation ; Dental Implants ; Dentistry ; Facial bones, jaws, teeth, parodontium: diseases, semeiology ; Femur - surgery ; Femur - ultrastructure ; Implants, Experimental ; Male ; Medical sciences ; nano-technology ; Nanotechnology - methods ; Non tumoral diseases ; osseointegration ; Osseointegration - drug effects ; Osseointegration - physiology ; Otorhinolaryngology. Stomatology ; Rabbits ; Surface Properties ; Titanium - chemistry ; TiUnite ; Zirconium - chemistry ; Zirconium - classification ; ZiUnite</subject><ispartof>Journal of clinical periodontology, 2009-07, Vol.36 (7), p.610-617</ispartof><rights>2009 John Wiley &amp; Sons A/S</rights><rights>2009 INIST-CNRS</rights><lds50>peer_reviewed</lds50><oa>free_for_read</oa><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c5833-9ec823c44ebdb4da4d5816f2089e3bdc3f3cd9c1d2b122672e33bf5fde80d98f3</citedby><cites>FETCH-LOGICAL-c5833-9ec823c44ebdb4da4d5816f2089e3bdc3f3cd9c1d2b122672e33bf5fde80d98f3</cites></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktopdf>$$Uhttps://onlinelibrary.wiley.com/doi/pdf/10.1111%2Fj.1600-051X.2009.01423.x$$EPDF$$P50$$Gwiley$$H</linktopdf><linktohtml>$$Uhttps://onlinelibrary.wiley.com/doi/full/10.1111%2Fj.1600-051X.2009.01423.x$$EHTML$$P50$$Gwiley$$H</linktohtml><link.rule.ids>314,776,780,1411,27903,27904,45553,45554</link.rule.ids><backlink>$$Uhttp://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetail&amp;idt=21614510$$DView record in Pascal Francis$$Hfree_for_read</backlink><backlink>$$Uhttps://www.ncbi.nlm.nih.gov/pubmed/19538335$$D View this record in MEDLINE/PubMed$$Hfree_for_read</backlink></links><search><creatorcontrib>Lee, Jaebum</creatorcontrib><creatorcontrib>Sieweke, Janet H.</creatorcontrib><creatorcontrib>Rodriguez, Nancy A.</creatorcontrib><creatorcontrib>Schüpbach, Peter</creatorcontrib><creatorcontrib>Lindström, Håkan</creatorcontrib><creatorcontrib>Susin, Cristiano</creatorcontrib><creatorcontrib>Wikesjö, Ulf M. E.</creatorcontrib><title>Evaluation of nano-technology-modified zirconia oral implants: a study in rabbits</title><title>Journal of clinical periodontology</title><addtitle>J Clin Periodontol</addtitle><description>Objective: The objective of this study was to screen candidate nano‐technology‐modified, micro‐structured zirconia implant surfaces relative to local bone formation and osseointegration. Materials and Methods: Proprietary nano‐technology surface‐modified (calcium phosphate: CaP) micro‐structured zirconia implants (A and C), control micro‐structured zirconia implants (ZiUnite™), and titanium porous oxide implants (TiUnite™) were implanted into the femoral condyle in 40 adult male New Zealand White rabbits. Each animal received one implant in each hind leg; thus, 20 animals received A and C implants and 20 animals received ZiUnite™ and TiUnite™ implants in contralateral hind legs. Ten animals/group were euthanized at weeks 3 and 6 when biopsies of the implant sites were processed for histometric analysis using digital photomicrographs produced using backscatter scanning electron microscopy. Results: The TiUnite™ surface demonstrated significantly greater bone–implant contact (BIC) (77.6±2.6%) compared with the A (64.6±3.6%) and C (62.2±3.1%) surfaces at 3 weeks (p&lt;0.05). Numerical differences between ZiUnite™ (70.5±3.1%) and A and C surfaces did not reach statistical significance (p&gt;0.05). Similarly, there were non‐significant differences between the TiUnite™ and the ZiUnite™ surfaces (p&gt;0.05). At 6 weeks, there were no significant differences in BIC between the TiUnite™ (67.1±4.2%), ZiUnite™ (69.7±5.7%), A (68.6±1.9%), and C (64.5±4.1%) surfaces (p&gt;0.05). Conclusion: TiUnite™ and ZiUnite™ implant surfaces exhibit high levels of osseointegration that, in this model, confirm their advanced osteoconductive properties. Addition of CaP nano‐technology to the ZiUnite™ surface does not enhance the already advanced osteoconductivity displayed by the TiUnite™ and ZiUnite™ implant surfaces.</description><subject>Animals</subject><subject>backscatter scanning electron microscopy</subject><subject>Biological and medical sciences</subject><subject>bone density</subject><subject>Bone Regeneration - drug effects</subject><subject>Bone Regeneration - physiology</subject><subject>bone-implant contact</subject><subject>calcium phosphate</subject><subject>Calcium Phosphates - chemistry</subject><subject>Coated Materials, Biocompatible - chemistry</subject><subject>Coated Materials, Biocompatible - pharmacology</subject><subject>Dental Implantation, Endosseous - instrumentation</subject><subject>Dental Implants</subject><subject>Dentistry</subject><subject>Facial bones, jaws, teeth, parodontium: diseases, semeiology</subject><subject>Femur - surgery</subject><subject>Femur - ultrastructure</subject><subject>Implants, Experimental</subject><subject>Male</subject><subject>Medical sciences</subject><subject>nano-technology</subject><subject>Nanotechnology - methods</subject><subject>Non tumoral diseases</subject><subject>osseointegration</subject><subject>Osseointegration - drug effects</subject><subject>Osseointegration - physiology</subject><subject>Otorhinolaryngology. Stomatology</subject><subject>Rabbits</subject><subject>Surface Properties</subject><subject>Titanium - chemistry</subject><subject>TiUnite</subject><subject>Zirconium - chemistry</subject><subject>Zirconium - classification</subject><subject>ZiUnite</subject><issn>0303-6979</issn><issn>1600-051X</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2009</creationdate><recordtype>article</recordtype><sourceid>EIF</sourceid><recordid>eNqNkE1v1DAQhi1ERbeFv4B8gVuC7YmTmAMSWi3bVlUBCQQ3y_EHeEnixU7aXX49CbtajjAXj-Rn3hk9CGFKcjrVq01OS0IywunXnBEickILBvnuEVqcPh6jBQECWSkqcY4uUtoQQisAeILOqeBQA_AF-ri6V-2oBh96HBzuVR-ywervfWjDt33WBeOdtwb_8lGH3iscomqx77at6of0GiuchtHsse9xVE3jh_QUnTnVJvvs-F6iz-9Wn5ZX2e379fXy7W2m-bQ6E1bXDHRR2MY0hVGF4TUtHSO1sNAYDQ60EZoa1lDGyopZgMZxZ2xNjKgdXKKXh9xtDD9HmwbZ-aRtOx1mw5hkWRUEBFT_BBkpay6AT2B9AHUMKUXr5Db6TsW9pETO3uVGznrlrFfO3uUf73I3jT4_7hibzpq_g0fRE_DiCKikVeui6rVPJ47Rkhackol7c-AefGv3_32AvFl-WM3tFJAdAnwa7O4UoOKPyQhUXH65W8v1TV0tiysq1_AbFfKuPQ</recordid><startdate>200907</startdate><enddate>200907</enddate><creator>Lee, Jaebum</creator><creator>Sieweke, Janet H.</creator><creator>Rodriguez, Nancy A.</creator><creator>Schüpbach, Peter</creator><creator>Lindström, Håkan</creator><creator>Susin, Cristiano</creator><creator>Wikesjö, Ulf M. E.</creator><general>Blackwell Publishing Ltd</general><general>Blackwell</general><scope>BSCLL</scope><scope>IQODW</scope><scope>CGR</scope><scope>CUY</scope><scope>CVF</scope><scope>ECM</scope><scope>EIF</scope><scope>NPM</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>7QO</scope><scope>7QP</scope><scope>8FD</scope><scope>FR3</scope><scope>P64</scope><scope>7X8</scope></search><sort><creationdate>200907</creationdate><title>Evaluation of nano-technology-modified zirconia oral implants: a study in rabbits</title><author>Lee, Jaebum ; Sieweke, Janet H. ; Rodriguez, Nancy A. ; Schüpbach, Peter ; Lindström, Håkan ; Susin, Cristiano ; Wikesjö, Ulf M. E.</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c5833-9ec823c44ebdb4da4d5816f2089e3bdc3f3cd9c1d2b122672e33bf5fde80d98f3</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2009</creationdate><topic>Animals</topic><topic>backscatter scanning electron microscopy</topic><topic>Biological and medical sciences</topic><topic>bone density</topic><topic>Bone Regeneration - drug effects</topic><topic>Bone Regeneration - physiology</topic><topic>bone-implant contact</topic><topic>calcium phosphate</topic><topic>Calcium Phosphates - chemistry</topic><topic>Coated Materials, Biocompatible - chemistry</topic><topic>Coated Materials, Biocompatible - pharmacology</topic><topic>Dental Implantation, Endosseous - instrumentation</topic><topic>Dental Implants</topic><topic>Dentistry</topic><topic>Facial bones, jaws, teeth, parodontium: diseases, semeiology</topic><topic>Femur - surgery</topic><topic>Femur - ultrastructure</topic><topic>Implants, Experimental</topic><topic>Male</topic><topic>Medical sciences</topic><topic>nano-technology</topic><topic>Nanotechnology - methods</topic><topic>Non tumoral diseases</topic><topic>osseointegration</topic><topic>Osseointegration - drug effects</topic><topic>Osseointegration - physiology</topic><topic>Otorhinolaryngology. Stomatology</topic><topic>Rabbits</topic><topic>Surface Properties</topic><topic>Titanium - chemistry</topic><topic>TiUnite</topic><topic>Zirconium - chemistry</topic><topic>Zirconium - classification</topic><topic>ZiUnite</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Lee, Jaebum</creatorcontrib><creatorcontrib>Sieweke, Janet H.</creatorcontrib><creatorcontrib>Rodriguez, Nancy A.</creatorcontrib><creatorcontrib>Schüpbach, Peter</creatorcontrib><creatorcontrib>Lindström, Håkan</creatorcontrib><creatorcontrib>Susin, Cristiano</creatorcontrib><creatorcontrib>Wikesjö, Ulf M. E.</creatorcontrib><collection>Istex</collection><collection>Pascal-Francis</collection><collection>Medline</collection><collection>MEDLINE</collection><collection>MEDLINE (Ovid)</collection><collection>MEDLINE</collection><collection>MEDLINE</collection><collection>PubMed</collection><collection>CrossRef</collection><collection>Biotechnology Research Abstracts</collection><collection>Calcium &amp; Calcified Tissue Abstracts</collection><collection>Technology Research Database</collection><collection>Engineering Research Database</collection><collection>Biotechnology and BioEngineering Abstracts</collection><collection>MEDLINE - Academic</collection><jtitle>Journal of clinical periodontology</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Lee, Jaebum</au><au>Sieweke, Janet H.</au><au>Rodriguez, Nancy A.</au><au>Schüpbach, Peter</au><au>Lindström, Håkan</au><au>Susin, Cristiano</au><au>Wikesjö, Ulf M. E.</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Evaluation of nano-technology-modified zirconia oral implants: a study in rabbits</atitle><jtitle>Journal of clinical periodontology</jtitle><addtitle>J Clin Periodontol</addtitle><date>2009-07</date><risdate>2009</risdate><volume>36</volume><issue>7</issue><spage>610</spage><epage>617</epage><pages>610-617</pages><issn>0303-6979</issn><eissn>1600-051X</eissn><abstract>Objective: The objective of this study was to screen candidate nano‐technology‐modified, micro‐structured zirconia implant surfaces relative to local bone formation and osseointegration. Materials and Methods: Proprietary nano‐technology surface‐modified (calcium phosphate: CaP) micro‐structured zirconia implants (A and C), control micro‐structured zirconia implants (ZiUnite™), and titanium porous oxide implants (TiUnite™) were implanted into the femoral condyle in 40 adult male New Zealand White rabbits. Each animal received one implant in each hind leg; thus, 20 animals received A and C implants and 20 animals received ZiUnite™ and TiUnite™ implants in contralateral hind legs. Ten animals/group were euthanized at weeks 3 and 6 when biopsies of the implant sites were processed for histometric analysis using digital photomicrographs produced using backscatter scanning electron microscopy. Results: The TiUnite™ surface demonstrated significantly greater bone–implant contact (BIC) (77.6±2.6%) compared with the A (64.6±3.6%) and C (62.2±3.1%) surfaces at 3 weeks (p&lt;0.05). Numerical differences between ZiUnite™ (70.5±3.1%) and A and C surfaces did not reach statistical significance (p&gt;0.05). Similarly, there were non‐significant differences between the TiUnite™ and the ZiUnite™ surfaces (p&gt;0.05). At 6 weeks, there were no significant differences in BIC between the TiUnite™ (67.1±4.2%), ZiUnite™ (69.7±5.7%), A (68.6±1.9%), and C (64.5±4.1%) surfaces (p&gt;0.05). Conclusion: TiUnite™ and ZiUnite™ implant surfaces exhibit high levels of osseointegration that, in this model, confirm their advanced osteoconductive properties. Addition of CaP nano‐technology to the ZiUnite™ surface does not enhance the already advanced osteoconductivity displayed by the TiUnite™ and ZiUnite™ implant surfaces.</abstract><cop>Oxford, UK</cop><pub>Blackwell Publishing Ltd</pub><pmid>19538335</pmid><doi>10.1111/j.1600-051X.2009.01423.x</doi><tpages>8</tpages><oa>free_for_read</oa></addata></record>
fulltext fulltext
identifier ISSN: 0303-6979
ispartof Journal of clinical periodontology, 2009-07, Vol.36 (7), p.610-617
issn 0303-6979
1600-051X
language eng
recordid cdi_proquest_miscellaneous_67403937
source MEDLINE; Wiley Online Library Journals Frontfile Complete
subjects Animals
backscatter scanning electron microscopy
Biological and medical sciences
bone density
Bone Regeneration - drug effects
Bone Regeneration - physiology
bone-implant contact
calcium phosphate
Calcium Phosphates - chemistry
Coated Materials, Biocompatible - chemistry
Coated Materials, Biocompatible - pharmacology
Dental Implantation, Endosseous - instrumentation
Dental Implants
Dentistry
Facial bones, jaws, teeth, parodontium: diseases, semeiology
Femur - surgery
Femur - ultrastructure
Implants, Experimental
Male
Medical sciences
nano-technology
Nanotechnology - methods
Non tumoral diseases
osseointegration
Osseointegration - drug effects
Osseointegration - physiology
Otorhinolaryngology. Stomatology
Rabbits
Surface Properties
Titanium - chemistry
TiUnite
Zirconium - chemistry
Zirconium - classification
ZiUnite
title Evaluation of nano-technology-modified zirconia oral implants: a study in rabbits
url https://sfx.bib-bvb.de/sfx_tum?ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&ctx_tim=2025-01-24T05%3A46%3A19IST&url_ver=Z39.88-2004&url_ctx_fmt=infofi/fmt:kev:mtx:ctx&rfr_id=info:sid/primo.exlibrisgroup.com:primo3-Article-proquest_cross&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.genre=article&rft.atitle=Evaluation%20of%20nano-technology-modified%20zirconia%20oral%20implants:%20a%20study%20in%20rabbits&rft.jtitle=Journal%20of%20clinical%20periodontology&rft.au=Lee,%20Jaebum&rft.date=2009-07&rft.volume=36&rft.issue=7&rft.spage=610&rft.epage=617&rft.pages=610-617&rft.issn=0303-6979&rft.eissn=1600-051X&rft_id=info:doi/10.1111/j.1600-051X.2009.01423.x&rft_dat=%3Cproquest_cross%3E20685935%3C/proquest_cross%3E%3Curl%3E%3C/url%3E&disable_directlink=true&sfx.directlink=off&sfx.report_link=0&rft_id=info:oai/&rft_pqid=20685935&rft_id=info:pmid/19538335&rfr_iscdi=true