Biomedical Engineering Reference
In-Depth Information
progression within the various areas, contributing to longer-term stabilities
and functionalities of dental implant-based restorative treatments.
Another aspect of peer review that involves most stakeholders is based
within professional organizations that develop consensus standards, such
as the American Dental Association (ADA) Standard Committee on Dental
Products (SCDP) [7]; the American Society for Testing and Materials (ASTM)
Committee F04 on Medical Devices [8]; and the International Standards
Organization (ISO) Technical Committee (TC) 106 [9] on dental products,
which includes standard subcommittees on restorative materials (SCIs) and
the SC8 on dental implants. Examples of specialized workshops and sym-
posia at ASTM that includes biomaterial and biomechanical information
are listed in Table 5.1. In all situations, ASTM and ADA standards have pro-
vided rapidly evolving documents since the 1960s that permit consistent use
of biomaterial and dental material products. Within the author's university
program this integrates dentistry, medicine (orthopedic surgery), and engi-
neering (materials and bioengineering). The program has received and ana-
lyzed more than 8,000 devices obtained from revision surgeries. Since 2005
[10] the program has evolved to now include postmortem in-situ specimens,
including the implant and the anatomical region supporting the implant.
Therefore, in most situations, this type of specimen—a device and pros-
thesis in place and functioning up to the time of death, followed by enbloc
retrieval—and its clinical history provide opportunities to evaluate clinical
success.
Results and Discussion
The bio- and dental materials utilized over the early decades (1950s-1980s)
of dental implant treatments included metallics, ceramics, polymerics, and
combinations/composites of these substances [11-17]. Examples of devices
received for examinations are shown in Figures 5.1-5.4. Central within
the metallics were the iron, cobalt, and titanium alloys. The ceramics were
constituted primarily from aluminum and zirconium oxides plus calcium
phosphate-based compounds. Ceramic biomaterials also included polycrys-
talline (vitreous) carbon and carbon-silicon. The polymerics primarily used
for dental implant body components were polyethylene, polymethyl meth-
acrylate, and polysulfone, with some use of porous combinations, including
modified polytetrafluoroethylene (Proplast
®
).
Dental materials included everything that was available for crowns,
bridges, bars, dentures, removable dentures, etc. This list is extensive, and
readers are referred to several dental materials topics [18-20] for the tech-
nical details. The metallics for crowns and bridges were often precious-
grade (Au, Pd, Pt) alloys plus base-metal (Ni, Co, Cr, Mo, Be) alloys with
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