FAILURE OF DENTAL PORCELAIN
FAILURE OF DENTAL PORCELAIN
批准号:
2132589
负责人:
SHANE NEWPORT WHITE
金额:
$4.68万
依托单位国家:
美国
项目类别:
财政年份:
1995
资助国家:
美国
项目状态:
已结题
起止时间:
1995-01-01 至 1996-12-31
中文摘要
近2300万克朗和400万座桥梁交付给美国
英文摘要
Almost 23 million crowns and 4 million bridges are delivered to American
patients annually, most of which are partly or completely made of
porcelain or other brittle ceramics. Unfortunately, failure due to
porcelain fracture necessitates the replacement of many restorations
after only short periods of service, and currently limits the application
of all-ceramic restorations. Increased use of all-ceramic restorations
is desirable due to superior biocompatibility and more pleasing
esthetics, but high clinical failure rates due to catastrophic fracture
limit their use. The goal of this proposal study is to define and
characterize the failure mechanism of dental porcelain using a fracture
mechanics model system.
Laboratory testing of dental porcelains and ceramics has used static
single-load test methods in the past. These static tests determine the
maximum stresses that can be tolerated, but are not valid for predicting
failure in clinical conditions where prostheses are usually subjected to
many subcritical load cycles before failure occurs. Dental ceramics and
glasses undergo chemical static fatigue in the presence of moisture at
ambient temperatures, but it has previously been assumed that these
materials do not undergo mechanical fatigue. However, White (1993) used
a fracture mechanics approach with a sharp indentation technique to
demonstrate the susceptibility of a dental porcelain to mechanical
fatigue, but was unable to characterize the phenomenon using that sharp
indentation technique. Therefore, the susceptibilities of dental
ceramics of mechanical fatigue, and the possible interaction between
cyclic mechanical and static chemical fatigue must be investigated to
identify failure mechanisms responsible for clinical failure.
A fracture mechanics approach using a new indentation technique is suited
to the fatigue characterization of brittle coarse grained materials, like
dental porcelains. Materials are indented multiple times and
microscopically examined of tested further. Experiments will test the
hypotheses that: (1) dental porcelain is susceptible to mechanical
fatigue, (2) mechanical fatigue, chemical fatigue, and their interaction
decrease the strength of dental porcelain, (3) all fatigue damage is
cumulative, (4) cracks may be initiated by a critical pressure, much
smaller than the pressure necessary for static failure, (5) the rate of
crack propagation varies with respect to pressure changes during load-
unloading cycles.
The results will define and quantify failure mechanisms. This knowledge
of failure mechanisms is essential to identify the best materials,
processing, and strengthening techniques, and is critical to the
development of new materials for in vivo applications. Better ceramic
materials will substantially decrease patient suffering and health care
costs by reducing the replacement of fractured prostheses, and will allow
greater application of all-ceramic prostheses.
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会议论文
Stress History is Recorded in Tooth Enamel
-
批准号:8260521
-
项目类别:
-
资助金额:$19.93万
-
财政年份:2011
-
负责人:SHANE NEWPORT WHITE
-
依托单位:
Stress History is Recorded in Tooth Enamel
-
批准号:8133315
-
项目类别:
-
资助金额:$21.33万
-
财政年份:2011
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负责人:SHANE NEWPORT WHITE
-
依托单位:
Dentino-enamel junction genetic-structural correlation
-
批准号:6775706
-
项目类别:
-
资助金额:$13.5万
-
财政年份:2002
-
负责人:SHANE NEWPORT WHITE
-
依托单位:
Dentino-enamel junction genetic-structural correlation
-
批准号:6613319
-
项目类别:
-
资助金额:$13.5万
-
财政年份:2002
-
负责人:SHANE NEWPORT WHITE
-
依托单位:
Dentino-enamel junction genetic-structural correlation
-
批准号:6472337
-
项目类别:
-
资助金额:$13.48万
-
财政年份:2002
-
负责人:SHANE NEWPORT WHITE
-
依托单位:
Dentino-enamel junction genetic-structural correlation
-
批准号:6946797
-
项目类别:
-
资助金额:$13.5万
-
财政年份:2002
-
负责人:SHANE NEWPORT WHITE
-
依托单位:
DESIGNED ENAMEL DEFECTS
-
批准号:2882732
-
项目类别:
-
资助金额:$3.82万
-
财政年份:1998
-
负责人:SHANE NEWPORT WHITE
-
依托单位:
DESIGNED ENAMEL DEFECTS
-
批准号:2634151
-
项目类别:
-
资助金额:$4.38万
-
财政年份:1998
-
负责人:SHANE NEWPORT WHITE
-
依托单位:
FAILURE OF DENTAL PORCELAIN
-
批准号:2132590
-
项目类别:
-
资助金额:$3.13万
-
财政年份:1995
-
负责人:SHANE NEWPORT WHITE
-
依托单位:
海外基金