The Journal
However, PEEK dental implants have not been
extensively used clinically and there is
insufficient data to deduce their long-term
efficacy in human subjects.
• PEEK as a removable prosthesismaterial
Dentures can be constructed by using PEEK
computer-aided design and computer-aided
manufacture systems [16] . Tan-nous et al. [17] has
suggested that denture clasps made of PEEK
have lower retentive forces compared to
[18]
cobalt–chromium (Co–Cr) clasps . However,
since the study was conducted on metal crowns
in vitro, it is not known how effective the esthetic
PEEK clasps would be in retaining dentures in
the clinical setting. Another application of PEEK
is the construction of a removable obturator [19] .
Nevertheless, more studies are needed to
evaluate the efficacy of PEEK obturators
compared to conventional acrylic prostheses.
To date, no clinical studies or systematic
reviews focusing on the use of PEEK dentures
have been published. However, owing to the
superior mechanical and biological properties
of PEEK, it will not be surprising if dentures
constructed from the polymer are routinely
constructed in near future.
• PEEK crowns
A variety of procedures have been suggested to
condition the surface of PEEK in order to
facilitate its bonding with resin composite
crowns. Even though air abrasion with and
without silica coating creates a more wettable
surface [20] , etching with sulphuric acid creates a
rough and chemically altered surface which
enables it to bond more effectively with
hydrophobic resin composites [21] . It has been
observed that etching with sulfuric acid for
60–90s can exhibit shear bond strength to resin
composite cements as high as 15.3 MPa after
[22]
being stored in water for 28 days at 370C .
Etching with piranha acid and using a bonding
agent have been shown to produce tensile bond
strength to composite resin as high as 23.9 MPa
in aged PEEK specimens [23]. No significant
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differences were observed in the tensile bond
strength of PEEK crowns and dentin abutments
using air abrasion and sulfuric acid etching
[24]
techniques
. These studies suggest that
PEEK can be used under resin-composite as a
coping material. Because the mechanical
properties of PEEK are similar to those of dentin
and enamel, PEEK could have an advantage
over alloy and ceramic restorations.
• PEEK CAD-CAM milled fixed partial
dentures
Using CAD-CAM to manufacture restorations
makes it possible to produce dental prostheses
chair-side [25] . CAD-CAM designed composites
and polymethylmethacrylate (PMMA) fixed
dentures have superior mechanical properties
compared to conventional fixed dentures [26] .
PEEK is another material that can be used an
alternative to PMMA for CAD-CAM
restorations. Three-unit PEEK fixed partial
denture manufactured via CAD-CAM has been
suggested to have a higher fracture resistance
than pressed granular- or pellet-shaped PEEK
dentur es [27] .
The fracture resistance of the CAD-CAM milled
PEEK fixed dentures is much higher than those
of lithium disilicate glass-ceramic (950N),
alumina (851N) [28] , zirconia (981-1331N) [29] . The
abrasive properties of PEEK are excellent.
Despite of significantly low elastic moduli and
hardness, abrasive resistance of PEEK is
[30]
competitive with metallic alloys . However, no
clinical studies have attempted to compare the
abrasion produced by PEEK crowns on teeth to
that produced by other materials such as alloys
and ceramics. Hence, it is still unknown if PEEK
crowns can function efficiently in harmony with
dentin and enamel. Considering good abrasion
resistance, mechanical attributes and
aforementioned adequate bonding to
composites and teeth, a PEEK fixed partial
denture would be expected to have a
satisfactory survival rate.
Vol. 13
12 No. 1
2
3
May-August
Sept-Dec 2017
Jan-April
2016
2016