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Table 1 In vitro studies included in the review

From: The use of PEEK in digital prosthodontics: A narrative review

Study (year) Application Materials tested Outcomes
Stawarczyk et al. (2015) [20] FDPs CAD-CAM milled PEEK
Pressed pellet PEEK
Pressed granular PEEK (n = 15/group)
Higher mean fracture load (2.354 N) for milled FPDs than those pressed from granular PEEK (1.738 N)
Stawarczyk et al. (2013) [22] CAD-CAM PEEK (n = 225) Μean fracture load of 1383 N Plastic deformation starting approximately at 1200 N
Niem et al.(2019) [23] CAD-CAM PEEK
Lithium disilicate glass-ceramic (n = 10/group)
PEEK exhibited
higher modulus of resilience than lithium disilicate
Comparable to that of gold alloy
Niem et al. (2019) [24] CAD-CAM PEEK
Composite and
Polymer-based materials
(n = 10 /group)
Flexural strength and modulus of elasticity of PEEK not significantly influenced by thermocycling
Liebermann et al. (2016) [25] PEEK
Hybrid material
Composite resins
PMMA-based materials (n = 40/group)
PEEK demonstrated:
The lowest solubility and water absorption
Similar hardness parameters to PMMA-based materials
Taufall et al. (2016) [26] CAD-CAM PEEK veneered with different methods
(digital veneering, conventional veneering with crea.lign, conventional with crea.lign paste, and pre-manufactured veneers) (n = 30/group)
The digital veneering showed the
highest fracture load resistance
Cekic-Nagas et al. (2018) [27] CAD-CAM PEEK
Composite resin and fiber-reinforced composite materials (n = 7/group)
Highest load bearing capacity for PEEK
Wimmer et al. (2016) [28] CAD-CAM PEEK
Nanohybrid composite
PMMA-based material
(n = 12/ group)
Significantly higher wear resistance for PEEK
Wachtel et al. (2019) [29] IFDPs CAD-CAM PEEK screw-retained crowns on titanium implants (n = 10) Favorable fracture mode for PEEK compared to conventional materials
Coronal displacement of bending points
No screw loosening or veneer fracture
Sirandoni et al. (2019) [30] CAD-CAM PEEK
Highest deformation for PEEK and PMMA frameworks that decreased von Mises stresses in the frameworks, implants and abutments
PEEK exhibited critical tensile stress values in the trabecular bone
Nazari et al. (2016) [31] CAD-CAM PEEK
Nickel-chromium alloy (n = 10/group)
3-unit IFDPs on two implants
Failure loads:
Zirconia 2086 ± 362 N
nickel-chromium alloy 5591 ± 1200 N
PEEK 1430 ± 262 N
Elsayed et al. (2019) [32] CAD-CAM PEEK
Lithium disilicate crowns supported by titanium and zirconia implant abutments (n = 8/group)
High fracture resistance of PEEK crowns, comparable to zirconia and lithium disilicate
Jin et al. (2019) [33] CAD-CAM PEEK and titanium frameworks veneered with composite resin n = 20/group PEEK exhibited
Higher shear bond strength than Ti, good marginal fit and fracture resistance (1518 N)
Preis et al. (2017) [1] CAD-CAM PEEK
Zirconia-reinforced lithium silicate ceramics
Composite resins
(n = 8/group)
PEEK molar implant-supported crowns showed lower fracture resistance than zirconia crowns
Total failure rate of PEEK screw-retained frameworks veneered with composite paste
Yilmaz et al. (2018) [34] Seven different CAD-CAM HPPs 100% PEEK
80% PEEK with 20% filler
80% PEKK with 20% filler Ceramic reinforced PEEK Interlaced fiberglass and resin Fiber-composite material
New generation cubic zirconia 3Y-TZP Zirconia
Higher fracture resistance for zirconia implant-supported frameworks with cantilevers than PEEK-based materials
Ghodsi et al. (2018) [35] CAD-CAM PEEK
(n = 12/group)
No clinically acceptable marginal gaps for PEEK
No significant differences observed in retention forces
Zeighami et al. (2019) [36] CAD-CAM PEEK
Composite (n = 12/group)
Better marginal adaptation for zirconia than PEEK
Chen et al. (2019) [37] RPDs CAD-CAM PEEK
Ti alloys
PEEK caused lower stresses on periodontal ligament and higher stresses on the mucosa
Tribst et al. (2020) [38] PEEK
Gold alloy
Polyoxymethylene and PEEK exhibited the lowest retentive forces
Peng et al. (2019) [39] PEEK
CoCr alloy
No significant difference in the long-term deformation
Muhsin et al. (2018) [40] CAD-CAM PEEK
granular PEEK
Co-Cr casting alloy
(n = 10/group)
Higher retentive force for milled PEEK clasps than thermopressed clasps
Higher retentive forces for PEEK clasps at deeper undercuts with a thicker clasp design than Co-Cr clasps after 3 years of fatigue simulation
Negm et al. (2019) [41] CAD-CAM Milled PEEK Thermo-pressed PEEK (n = 10/group) Higher fit and trueness for directly milled frameworks
Arnold et al. (2018) [42] CAD-CAM Milled PEEK
Cast metal frameworks with different techniques (n = 12/group)
PEEK RPD frameworks have better precision and fit than metal frameworks fabricated using different techniques
Hada et al. (2020) [43] Complete denture framework PEEK
Fiber-reinforced composite
cobalt-chromium-molybdenum alloy (n = 6group)
PEEK provides lower reinforcement than the other materials
Emera et al. (2019) [5] Double-crown-retained Removable Dental Prostheses Zirconia or PEEK primary crowns
Zirconia or PEEK secondary crowns
Telescopic attachments fabricated from zirconia primary crowns and PEEK secondary crowns exhibited the lowest stresses transmitted to the implants
Schubert et al. (2019) [44] Implant-supported zirconia primary crowns with
electroformed secondary crowns or CAD-CAM PEEK secondary crowns (n = 10/group)
Stable retentive force values over 10 years of simulated aging for PEEK secondary crowns
Merk et al. (2016) [45] Zirconia primary crowns
Secondary PEEK crowns of different taper and manufacturing methods;
milled from PEEK blanks; thermo-pressed from PEEK pellets;
thermo-pressed from granular PEEK (n = 10/group)
Fabrication method and taper angle had no consistent effect on retentive forces within different groups
Stock et al. (2016) [46] Zirconia primary crowns
Secondary PEEK crowns of different taper and manufacturing methods;
milled from PEEK blanks; thermo-pressed from PEEK pellets;
thermo-pressed from granular PEEK (n = 30/group)
Milled 0° tapered PEEK crowns presented the lowest retention force
Milled 2° tapered PEEK crowns had the highest retention force values
Retention force of pressed PEEK not influenced by the taper angle
Decrease of retention after the first twenty pull-off cyclew for pressed PEEK
Wagner et al. (2018) [47] PEEK telescopic crowns and cobalt chrome copings of different taper and manufacturing methods (n = 10/group) Stable retention load values for each test group
Stock et al. (2016) [48] Milled PEEK primary and cobalt-chromium (CoCr), zirconia (ZrO2) and galvanic
(GAL) secondary crowns with three different tapers (n = 30, 10/taper)
Milled PEEK can be used as primary crown material with high retentive forces in combination with secondary zirconia, cobalt-chromium or electroformed crowns
Benli et al. (2020) [11] Occlusal splint CAD-CAM PEEK
Vinyl acetate
Polymethyl methacrylate
(n = 12/group)
After chewing simulation PEEK occlusal splints exhibited lower loss of volume and lower roughness alteration compared to other CAD-CAM materials
Benli et al. (2020) [49] Intra-radicular posts Milled PEEK
(n = 20/group)
PEEK posts exhibited the highest tensile bond strength and the lowest surface roughness
Kaleli et al. (2018) [9] Implant abutments PEEK and zirconia customized abutments Finite element analysis showed higher stress values in restorative crowns for PEEK abutments
Abdullah et al. (2016) [50] Provisional crowns PEEK
Telio CAD-Temp
Protemp 4
PEEK demonstrated superior fit and fracture strength than other materials