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Philipps-Universität Marburg
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Abstract
Concentrating on the classic field of fixed
partial dentures a tooth normally has to be prepared through
the enamel into the dentine-surface for complete coverage
restorations. With preparation there accures a dentine-wound.
Its extension depends on the number and total extrusion of
injured dentine tubules. Beside other parameters like for
example the influence of rising temperature on the
preparation-surface and effects of chemical components within
dental filling materials, there was discussed intensively the
importance of remaining dentine-thickness above the pulp after
tooth preparation in order to keep pulp sensitivity and
vitality of the tooth.
The postulation to limite preparation
at a minimum thickness of dentine of 0,7 mm for teeth of adults
and 1,4 mm for teeth of adolescent persons is wellknown and
established in Germany (Jüde et al. 1997). These differences
show, that even in the past, there was considered the different
structure of dentine, which could be responsible for varying
permeability for supposable damaging agents.
Various studies
from Gente and coworkers (Gente 1987, Feige 1989, Wenz 1990,
Gente and Wenz 1991, Gente 1992, Becker-Detert 1993, Gente
1995, Netsch 1995) show, that the method of measuring
electrical resistance on the tooths surface to limite the depth
of preparation is to prefer to other techniques like for
example the preparation of depth cuts or the interpretation of
x-rays. Gente developed a procedure, which was recommended to
users already in 1999 by the German Society of Dentistry and
Oral Medicine (GSDOM) in their official statement "preparation
technique as basis for quality assurance". But in the same
statement the authors again citate the established data for
minimum dentin-thickness as described above (Hellwig et al.
1999). The results of the present study clarify, that these
specifications have to be questioned critically within further
clinical trials.
The used device to limite preparation depth
(Prepometer®, Hager & Werken, Germany) shows the dentist by
flashing of 10 different coloured light emitting diodes (LEDs)
the progress of substance reduction. The manufacturer
recommends a preparation only up to LED Nr. 7 (orange coloured)
to avoid pulpal injury.
The results of the present
experimental record (in-vitro) demonstrate, that after reducing
enamel and dentine to the minimum of 0,7 mm , described as
reference data for adults by Jüde and coworkers (Jüde at al.
1997), there was exceeded the recommended preparation depth,
concerning to orange coloured LED Nr. 7 in nearly 93% of the
examined measuring points. At this time possible symptoms of a
perhaps irreversible injury of the pulp can only be proven in
histology.
There exists no constant data of dentin thickness,
related to the different LEDs. The results of Netsch (Netsch
1995) are confirmed. He figured out, that the dentist has to
pay attention more to the surface area of the dentine wound and
its permeability and less to the minimum thickness of dentine
to avoid pulpal injury. The functionality of the Prepometer®
follows this principle by measuring local electrical
resistance.
The results of the present clinical record
(in-vivo) attest the application of the Prepometer® positive
reference data. All teeth, prepared with control-measurement by
the Prepometer®, kept a positive pulpal sensitivity up to the
time of 2-5 years. In the control group however 21,1% of the
examined teeth had a negative pulp testing. This results are
comparable with other wide spreading data between 0,06% - 25%
and different study-designs in the dental literature.
Based
on the results of the described present studies, we can
recommend an extended use of the Prepometer® for quality
assurance. The data should be reevaluated in a bigger
test-group within further clinical trials. Then there has to be
examined also the practicability of the described method on
structural alterated dentine, influenced by age or adaptation
to pathologic processes.
Review
Metadata
Contributors
Supervisor:
Dates
Created: 2003Issued: 2004-01-22Updated: 2011-08-10
Faculty
Medizin
Publisher
Philipps-Universität Marburg
Language
ger
Data types
DoctoralThesis
Keywords
tooth preparation, electrical resistanceZahnpräparation , Prepometer®dentine surface , prepometer®
DFG-subjects
DentinkanälchenKavitätenpräparationDentinWiderstandsmessung
DDC-Numbers
610
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Bruchmann, Susanne (128719974): In-vitro und in-vivo Untersuchungen zum Prepometer®. : Philipps-Universität Marburg 2004-01-22. DOI: https://doi.org/10.17192/z2004.0008.
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This item has been published with the following license: In Copyright