A comparison of biocompatibility and osseointegration of ceramic and titanium implants: an in vivo and in vitro study

Abstract This study compared the biocompatibility in vitro and the osseointegration in vivo of zirconium and titanium implants regarding implant surfaces and the bone–implant contacts. The different implant surfaces and the biocompatibility of zirconium versus titanium implants were determined by vi...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:International journal of oral and maxillofacial surgery 2012-05, Vol.41 (5), p.638-645
Hauptverfasser: Möller, B, Terheyden, H, Açil, Y, Purcz, N.M, Hertrampf, K, Tabakov, A, Behrens, E, Wiltfang, J
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
container_end_page 645
container_issue 5
container_start_page 638
container_title International journal of oral and maxillofacial surgery
container_volume 41
creator Möller, B
Terheyden, H
Açil, Y
Purcz, N.M
Hertrampf, K
Tabakov, A
Behrens, E
Wiltfang, J
description Abstract This study compared the biocompatibility in vitro and the osseointegration in vivo of zirconium and titanium implants regarding implant surfaces and the bone–implant contacts. The different implant surfaces and the biocompatibility of zirconium versus titanium implants were determined by vitality and cytotoxic tests in vitro . The contact of the osteoblasts to the implant surface was determined by scanning electron microscopy (SEM). The in vivo study for osseointegration was performed in domestic pigs over 4 and 12 weeks. In each animal, 4 zirconium and 4 titanium implants (WhiteSky, BlueSky, Bredent, Germany) were inserted in the os frontale and analysed by histomorphometry. Cytotoxicity and SEM showed good biocompatibility in relation to the investigated implant materials. Histological results showed direct bone–implant contact of the implant surfaces. The zirconium implants showed a slight delay in osseointegration in terms of bone–implant contact as measured by histomorphometry (after 4 weeks, zirconium (59.3 ± 4.6%) versus titanium (64.1 ± 3.9%); after 12 weeks, zirconium (67.1 ± 2.3%) versus titanium (73.6 ± 3.2%). A statistically significant difference between the two groups was not observed. The results indicated similar biocompatibility and osseointegration for zirconium compared to titanium implants.
doi_str_mv 10.1016/j.ijom.2012.02.004
format Article
fullrecord <record><control><sourceid>proquest_cross</sourceid><recordid>TN_cdi_proquest_miscellaneous_1008830019</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><els_id>S0901502712000690</els_id><sourcerecordid>1008830019</sourcerecordid><originalsourceid>FETCH-LOGICAL-c507t-35ceee3c3a2f77f9b5d0344a44164f4db0120bcf2d657e1f57565d8e5a4808593</originalsourceid><addsrcrecordid>eNp9kk2LFDEQhoMo7rj6BzxIXwQvPVY6SX-ILCyLX7DgQT2HdLpaauxOxiQ9MP_e9Myo4EEIJFQ9b6XqpRh7zmHLgdevd1va-XlbAa-2kA_IB2zDRdeVABU8ZBvogJcKquaKPYlxBwCdaJvH7KqqJNSVUBu23BbWz3sTKHpX-LHoyZ8CiXqaKB0L44bCx4ieXMLvISfOoMVgZrKnfKJkHC1zQfN-Mi7FNzlckCsOdPAn4vROwRcxLcPxKXs0minis8t9zb69f_f17mN5__nDp7vb-9IqaFIplEVEYYWpxqYZu14NIKQ0UvJajnLo8-TQ27EaatUgH1WjajW0qIxsoVWduGavznX3wf9cMCY9U7Q45R7RL1FzgLYVAHxFqzNqQ5424Kj3gWYTjhnSq916p1e79Wq3hnxAZtGLS_2ln3H4I_ntbwZeXgATrZnGYJyl-JdTLVdS1Jl7e-Ywu3EgDDpaQmdxoIA26cHT__u4-UduJ3KUf_yBR4w7vwSXfdZcxyzQX9bFWPci2wdQdyB-AU7zs8E</addsrcrecordid><sourcetype>Aggregation Database</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype><pqid>1008830019</pqid></control><display><type>article</type><title>A comparison of biocompatibility and osseointegration of ceramic and titanium implants: an in vivo and in vitro study</title><source>MEDLINE</source><source>Elsevier ScienceDirect Journals</source><creator>Möller, B ; Terheyden, H ; Açil, Y ; Purcz, N.M ; Hertrampf, K ; Tabakov, A ; Behrens, E ; Wiltfang, J</creator><creatorcontrib>Möller, B ; Terheyden, H ; Açil, Y ; Purcz, N.M ; Hertrampf, K ; Tabakov, A ; Behrens, E ; Wiltfang, J</creatorcontrib><description>Abstract This study compared the biocompatibility in vitro and the osseointegration in vivo of zirconium and titanium implants regarding implant surfaces and the bone–implant contacts. The different implant surfaces and the biocompatibility of zirconium versus titanium implants were determined by vitality and cytotoxic tests in vitro . The contact of the osteoblasts to the implant surface was determined by scanning electron microscopy (SEM). The in vivo study for osseointegration was performed in domestic pigs over 4 and 12 weeks. In each animal, 4 zirconium and 4 titanium implants (WhiteSky, BlueSky, Bredent, Germany) were inserted in the os frontale and analysed by histomorphometry. Cytotoxicity and SEM showed good biocompatibility in relation to the investigated implant materials. Histological results showed direct bone–implant contact of the implant surfaces. The zirconium implants showed a slight delay in osseointegration in terms of bone–implant contact as measured by histomorphometry (after 4 weeks, zirconium (59.3 ± 4.6%) versus titanium (64.1 ± 3.9%); after 12 weeks, zirconium (67.1 ± 2.3%) versus titanium (73.6 ± 3.2%). A statistically significant difference between the two groups was not observed. The results indicated similar biocompatibility and osseointegration for zirconium compared to titanium implants.</description><identifier>ISSN: 0901-5027</identifier><identifier>EISSN: 1399-0020</identifier><identifier>DOI: 10.1016/j.ijom.2012.02.004</identifier><identifier>PMID: 22406235</identifier><identifier>CODEN: IJOSE9</identifier><language>eng</language><publisher>Kidlington: Elsevier Ltd</publisher><subject>Animals ; biocompatibility ; Biocompatible Materials - chemistry ; Biocompatible Materials - toxicity ; Biological and medical sciences ; Bone Matrix - anatomy &amp; histology ; Bromodeoxyuridine ; Cell Culture Techniques ; cell growth ; Cell Proliferation - drug effects ; Cell Survival - drug effects ; Ceramics - chemistry ; Ceramics - toxicity ; Coloring Agents ; Dental Implants ; Dental Materials - chemistry ; Dental Materials - toxicity ; Dental Prosthesis Design ; Dentistry ; Female ; Fluoresceins ; Fluorescent Dyes ; Frontal Bone - anatomy &amp; histology ; Frontal Bone - surgery ; Head and neck surgery. Maxillofacial surgery. Dental surgery. Orthodontics ; Humans ; L-Lactate Dehydrogenase - analysis ; Materials Testing ; Maxillofacial surgery. Dental surgery. Orthodontics ; Medical sciences ; Microscopy, Electron, Scanning ; Models, Animal ; osseointegration ; Osseointegration - physiology ; Osteoblasts - drug effects ; Osteoblasts - ultrastructure ; Osteocalcin - analysis ; Otorhinolaryngology. Stomatology ; Surgery ; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases ; Swine ; Tetrazolium Salts ; Thiazoles ; Time Factors ; Titanium - chemistry ; Titanium - toxicity ; zirconia ; Zirconium - chemistry ; Zirconium - toxicity</subject><ispartof>International journal of oral and maxillofacial surgery, 2012-05, Vol.41 (5), p.638-645</ispartof><rights>International Association of Oral and Maxillofacial Surgeons</rights><rights>2012 International Association of Oral and Maxillofacial Surgeons</rights><rights>2015 INIST-CNRS</rights><rights>Copyright © 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.</rights><lds50>peer_reviewed</lds50><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c507t-35ceee3c3a2f77f9b5d0344a44164f4db0120bcf2d657e1f57565d8e5a4808593</citedby><cites>FETCH-LOGICAL-c507t-35ceee3c3a2f77f9b5d0344a44164f4db0120bcf2d657e1f57565d8e5a4808593</cites></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktohtml>$$Uhttps://www.sciencedirect.com/science/article/pii/S0901502712000690$$EHTML$$P50$$Gelsevier$$H</linktohtml><link.rule.ids>314,776,780,3537,27901,27902,65306</link.rule.ids><backlink>$$Uhttp://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetail&amp;idt=25815436$$DView record in Pascal Francis$$Hfree_for_read</backlink><backlink>$$Uhttps://www.ncbi.nlm.nih.gov/pubmed/22406235$$D View this record in MEDLINE/PubMed$$Hfree_for_read</backlink></links><search><creatorcontrib>Möller, B</creatorcontrib><creatorcontrib>Terheyden, H</creatorcontrib><creatorcontrib>Açil, Y</creatorcontrib><creatorcontrib>Purcz, N.M</creatorcontrib><creatorcontrib>Hertrampf, K</creatorcontrib><creatorcontrib>Tabakov, A</creatorcontrib><creatorcontrib>Behrens, E</creatorcontrib><creatorcontrib>Wiltfang, J</creatorcontrib><title>A comparison of biocompatibility and osseointegration of ceramic and titanium implants: an in vivo and in vitro study</title><title>International journal of oral and maxillofacial surgery</title><addtitle>Int J Oral Maxillofac Surg</addtitle><description>Abstract This study compared the biocompatibility in vitro and the osseointegration in vivo of zirconium and titanium implants regarding implant surfaces and the bone–implant contacts. The different implant surfaces and the biocompatibility of zirconium versus titanium implants were determined by vitality and cytotoxic tests in vitro . The contact of the osteoblasts to the implant surface was determined by scanning electron microscopy (SEM). The in vivo study for osseointegration was performed in domestic pigs over 4 and 12 weeks. In each animal, 4 zirconium and 4 titanium implants (WhiteSky, BlueSky, Bredent, Germany) were inserted in the os frontale and analysed by histomorphometry. Cytotoxicity and SEM showed good biocompatibility in relation to the investigated implant materials. Histological results showed direct bone–implant contact of the implant surfaces. The zirconium implants showed a slight delay in osseointegration in terms of bone–implant contact as measured by histomorphometry (after 4 weeks, zirconium (59.3 ± 4.6%) versus titanium (64.1 ± 3.9%); after 12 weeks, zirconium (67.1 ± 2.3%) versus titanium (73.6 ± 3.2%). A statistically significant difference between the two groups was not observed. The results indicated similar biocompatibility and osseointegration for zirconium compared to titanium implants.</description><subject>Animals</subject><subject>biocompatibility</subject><subject>Biocompatible Materials - chemistry</subject><subject>Biocompatible Materials - toxicity</subject><subject>Biological and medical sciences</subject><subject>Bone Matrix - anatomy &amp; histology</subject><subject>Bromodeoxyuridine</subject><subject>Cell Culture Techniques</subject><subject>cell growth</subject><subject>Cell Proliferation - drug effects</subject><subject>Cell Survival - drug effects</subject><subject>Ceramics - chemistry</subject><subject>Ceramics - toxicity</subject><subject>Coloring Agents</subject><subject>Dental Implants</subject><subject>Dental Materials - chemistry</subject><subject>Dental Materials - toxicity</subject><subject>Dental Prosthesis Design</subject><subject>Dentistry</subject><subject>Female</subject><subject>Fluoresceins</subject><subject>Fluorescent Dyes</subject><subject>Frontal Bone - anatomy &amp; histology</subject><subject>Frontal Bone - surgery</subject><subject>Head and neck surgery. Maxillofacial surgery. Dental surgery. Orthodontics</subject><subject>Humans</subject><subject>L-Lactate Dehydrogenase - analysis</subject><subject>Materials Testing</subject><subject>Maxillofacial surgery. Dental surgery. Orthodontics</subject><subject>Medical sciences</subject><subject>Microscopy, Electron, Scanning</subject><subject>Models, Animal</subject><subject>osseointegration</subject><subject>Osseointegration - physiology</subject><subject>Osteoblasts - drug effects</subject><subject>Osteoblasts - ultrastructure</subject><subject>Osteocalcin - analysis</subject><subject>Otorhinolaryngology. Stomatology</subject><subject>Surgery</subject><subject>Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases</subject><subject>Swine</subject><subject>Tetrazolium Salts</subject><subject>Thiazoles</subject><subject>Time Factors</subject><subject>Titanium - chemistry</subject><subject>Titanium - toxicity</subject><subject>zirconia</subject><subject>Zirconium - chemistry</subject><subject>Zirconium - toxicity</subject><issn>0901-5027</issn><issn>1399-0020</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2012</creationdate><recordtype>article</recordtype><sourceid>EIF</sourceid><recordid>eNp9kk2LFDEQhoMo7rj6BzxIXwQvPVY6SX-ILCyLX7DgQT2HdLpaauxOxiQ9MP_e9Myo4EEIJFQ9b6XqpRh7zmHLgdevd1va-XlbAa-2kA_IB2zDRdeVABU8ZBvogJcKquaKPYlxBwCdaJvH7KqqJNSVUBu23BbWz3sTKHpX-LHoyZ8CiXqaKB0L44bCx4ieXMLvISfOoMVgZrKnfKJkHC1zQfN-Mi7FNzlckCsOdPAn4vROwRcxLcPxKXs0minis8t9zb69f_f17mN5__nDp7vb-9IqaFIplEVEYYWpxqYZu14NIKQ0UvJajnLo8-TQ27EaatUgH1WjajW0qIxsoVWduGavznX3wf9cMCY9U7Q45R7RL1FzgLYVAHxFqzNqQ5424Kj3gWYTjhnSq916p1e79Wq3hnxAZtGLS_2ln3H4I_ntbwZeXgATrZnGYJyl-JdTLVdS1Jl7e-Ywu3EgDDpaQmdxoIA26cHT__u4-UduJ3KUf_yBR4w7vwSXfdZcxyzQX9bFWPci2wdQdyB-AU7zs8E</recordid><startdate>20120501</startdate><enddate>20120501</enddate><creator>Möller, B</creator><creator>Terheyden, H</creator><creator>Açil, Y</creator><creator>Purcz, N.M</creator><creator>Hertrampf, K</creator><creator>Tabakov, A</creator><creator>Behrens, E</creator><creator>Wiltfang, J</creator><general>Elsevier Ltd</general><general>Elsevier</general><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>7X8</scope></search><sort><creationdate>20120501</creationdate><title>A comparison of biocompatibility and osseointegration of ceramic and titanium implants: an in vivo and in vitro study</title><author>Möller, B ; Terheyden, H ; Açil, Y ; Purcz, N.M ; Hertrampf, K ; Tabakov, A ; Behrens, E ; Wiltfang, J</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c507t-35ceee3c3a2f77f9b5d0344a44164f4db0120bcf2d657e1f57565d8e5a4808593</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2012</creationdate><topic>Animals</topic><topic>biocompatibility</topic><topic>Biocompatible Materials - chemistry</topic><topic>Biocompatible Materials - toxicity</topic><topic>Biological and medical sciences</topic><topic>Bone Matrix - anatomy &amp; histology</topic><topic>Bromodeoxyuridine</topic><topic>Cell Culture Techniques</topic><topic>cell growth</topic><topic>Cell Proliferation - drug effects</topic><topic>Cell Survival - drug effects</topic><topic>Ceramics - chemistry</topic><topic>Ceramics - toxicity</topic><topic>Coloring Agents</topic><topic>Dental Implants</topic><topic>Dental Materials - chemistry</topic><topic>Dental Materials - toxicity</topic><topic>Dental Prosthesis Design</topic><topic>Dentistry</topic><topic>Female</topic><topic>Fluoresceins</topic><topic>Fluorescent Dyes</topic><topic>Frontal Bone - anatomy &amp; histology</topic><topic>Frontal Bone - surgery</topic><topic>Head and neck surgery. Maxillofacial surgery. Dental surgery. Orthodontics</topic><topic>Humans</topic><topic>L-Lactate Dehydrogenase - analysis</topic><topic>Materials Testing</topic><topic>Maxillofacial surgery. Dental surgery. Orthodontics</topic><topic>Medical sciences</topic><topic>Microscopy, Electron, Scanning</topic><topic>Models, Animal</topic><topic>osseointegration</topic><topic>Osseointegration - physiology</topic><topic>Osteoblasts - drug effects</topic><topic>Osteoblasts - ultrastructure</topic><topic>Osteocalcin - analysis</topic><topic>Otorhinolaryngology. Stomatology</topic><topic>Surgery</topic><topic>Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases</topic><topic>Swine</topic><topic>Tetrazolium Salts</topic><topic>Thiazoles</topic><topic>Time Factors</topic><topic>Titanium - chemistry</topic><topic>Titanium - toxicity</topic><topic>zirconia</topic><topic>Zirconium - chemistry</topic><topic>Zirconium - toxicity</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Möller, B</creatorcontrib><creatorcontrib>Terheyden, H</creatorcontrib><creatorcontrib>Açil, Y</creatorcontrib><creatorcontrib>Purcz, N.M</creatorcontrib><creatorcontrib>Hertrampf, K</creatorcontrib><creatorcontrib>Tabakov, A</creatorcontrib><creatorcontrib>Behrens, E</creatorcontrib><creatorcontrib>Wiltfang, J</creatorcontrib><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>MEDLINE - Academic</collection><jtitle>International journal of oral and maxillofacial surgery</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Möller, B</au><au>Terheyden, H</au><au>Açil, Y</au><au>Purcz, N.M</au><au>Hertrampf, K</au><au>Tabakov, A</au><au>Behrens, E</au><au>Wiltfang, J</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>A comparison of biocompatibility and osseointegration of ceramic and titanium implants: an in vivo and in vitro study</atitle><jtitle>International journal of oral and maxillofacial surgery</jtitle><addtitle>Int J Oral Maxillofac Surg</addtitle><date>2012-05-01</date><risdate>2012</risdate><volume>41</volume><issue>5</issue><spage>638</spage><epage>645</epage><pages>638-645</pages><issn>0901-5027</issn><eissn>1399-0020</eissn><coden>IJOSE9</coden><abstract>Abstract This study compared the biocompatibility in vitro and the osseointegration in vivo of zirconium and titanium implants regarding implant surfaces and the bone–implant contacts. The different implant surfaces and the biocompatibility of zirconium versus titanium implants were determined by vitality and cytotoxic tests in vitro . The contact of the osteoblasts to the implant surface was determined by scanning electron microscopy (SEM). The in vivo study for osseointegration was performed in domestic pigs over 4 and 12 weeks. In each animal, 4 zirconium and 4 titanium implants (WhiteSky, BlueSky, Bredent, Germany) were inserted in the os frontale and analysed by histomorphometry. Cytotoxicity and SEM showed good biocompatibility in relation to the investigated implant materials. Histological results showed direct bone–implant contact of the implant surfaces. The zirconium implants showed a slight delay in osseointegration in terms of bone–implant contact as measured by histomorphometry (after 4 weeks, zirconium (59.3 ± 4.6%) versus titanium (64.1 ± 3.9%); after 12 weeks, zirconium (67.1 ± 2.3%) versus titanium (73.6 ± 3.2%). A statistically significant difference between the two groups was not observed. The results indicated similar biocompatibility and osseointegration for zirconium compared to titanium implants.</abstract><cop>Kidlington</cop><pub>Elsevier Ltd</pub><pmid>22406235</pmid><doi>10.1016/j.ijom.2012.02.004</doi><tpages>8</tpages></addata></record>
fulltext fulltext
identifier ISSN: 0901-5027
ispartof International journal of oral and maxillofacial surgery, 2012-05, Vol.41 (5), p.638-645
issn 0901-5027
1399-0020
language eng
recordid cdi_proquest_miscellaneous_1008830019
source MEDLINE; Elsevier ScienceDirect Journals
subjects Animals
biocompatibility
Biocompatible Materials - chemistry
Biocompatible Materials - toxicity
Biological and medical sciences
Bone Matrix - anatomy & histology
Bromodeoxyuridine
Cell Culture Techniques
cell growth
Cell Proliferation - drug effects
Cell Survival - drug effects
Ceramics - chemistry
Ceramics - toxicity
Coloring Agents
Dental Implants
Dental Materials - chemistry
Dental Materials - toxicity
Dental Prosthesis Design
Dentistry
Female
Fluoresceins
Fluorescent Dyes
Frontal Bone - anatomy & histology
Frontal Bone - surgery
Head and neck surgery. Maxillofacial surgery. Dental surgery. Orthodontics
Humans
L-Lactate Dehydrogenase - analysis
Materials Testing
Maxillofacial surgery. Dental surgery. Orthodontics
Medical sciences
Microscopy, Electron, Scanning
Models, Animal
osseointegration
Osseointegration - physiology
Osteoblasts - drug effects
Osteoblasts - ultrastructure
Osteocalcin - analysis
Otorhinolaryngology. Stomatology
Surgery
Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases
Swine
Tetrazolium Salts
Thiazoles
Time Factors
Titanium - chemistry
Titanium - toxicity
zirconia
Zirconium - chemistry
Zirconium - toxicity
title A comparison of biocompatibility and osseointegration of ceramic and titanium implants: an in vivo and in vitro study
url https://sfx.bib-bvb.de/sfx_tum?ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&ctx_tim=2025-02-04T10%3A05%3A44IST&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=A%20comparison%20of%20biocompatibility%20and%20osseointegration%20of%20ceramic%20and%20titanium%20implants:%20an%20in%20vivo%20and%20in%20vitro%20study&rft.jtitle=International%20journal%20of%20oral%20and%20maxillofacial%20surgery&rft.au=M%C3%B6ller,%20B&rft.date=2012-05-01&rft.volume=41&rft.issue=5&rft.spage=638&rft.epage=645&rft.pages=638-645&rft.issn=0901-5027&rft.eissn=1399-0020&rft.coden=IJOSE9&rft_id=info:doi/10.1016/j.ijom.2012.02.004&rft_dat=%3Cproquest_cross%3E1008830019%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=1008830019&rft_id=info:pmid/22406235&rft_els_id=S0901502712000690&rfr_iscdi=true