Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
18
pubmed:dateCreated
2004-3-29
pubmed:abstractText
The formation and strengthening mechanisms of bone bonding of crystalline hydroxyapatite (HA) has been investigated using high-resolution transmission electron microscope (HRTEM) and energy-dispersive X-ray (EDX) analysis. A series of results were obtained: (i) a layer of amorphous HA, which has almost the same chemistry as the implanted HA, was formed on the surface of crystalline HA particles prior to dissolution; (ii) at 3 months a bone-like tissue formed a bonding zone between mature bone and the HA implant, composed of nanocrystalline and amorphous apatite; and (iii) at 6 months, mature bone was in direct contact with HA particles, and collagen fibres were perpendicularly inserted into the surface layer of implanted HA crystals. Findings (i) and (ii) indicated the following dissolution-precipitation process. (i) The crystalline HA transforms into amorphous HA; (ii) the amorphous HA dissolves into the surrounding solution, resulting in over-saturation; and (iii) the nanocrystallites are precipitated from the over-saturated solution in the presence of collagen fibres. A preliminary analysis indicated several conclusions: (i) the transition from crystalline to amorphous HA might be the controlling step in the bone bonding of crystalline HA; (ii) biological interdigitation (or incorporation) of collagen fibres with HA and chemical bonding of a apatite layer were both necessary to strengthen and toughen a bone bond, not only for the bonding between bone and HA at 6 months, but also for the bonding zone at 3 months, which would otherwise be very fragile due to the inherited brittleness of polycrystalline ceramics; and (iii) perpendicular interdigitation is an effective way for collagen fibres to impart their unique combination of flexibility and strength to the interface which they are keying.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0142-9612
pubmed:author
pubmed:issnType
Print
pubmed:volume
25
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4243-54
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Strengthening mechanisms of bone bonding to crystalline hydroxyapatite in vivo.
pubmed:affiliation
Department of Mechanical Engineering, University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China. qzchen@hkucc.hku.hk
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't, Evaluation Studies