Comparison of fit of poly (etheretherketone) and cobalt-chromium removable partial denture frames: an in-vitro study.


  • Ary Yaqoub Putros Department of Prosthodontics, College of Dentistry, Hawler Medical University, Erbil, Iraq.
  • Jawad Mohammed Mikaeel Department of Prosthodontics, College of Dentistry, Hawler Medical University, Erbil, Iraq.



fit accuracy, laboratory research, removable partial denture framework


Background and objective: the adaptation of the Removable partial denture (RPD) is a key factor in the success of the treatment outcome. This study aims to compare the fit of Poly(etheretherketone)(PEEK) and cobalt-chromium (Co-Cr) frames through the rest seat adaptation

Methods: Ideal typodont model of the maxillary partially edentulous case (Kennedy Class III), four rest seats were prepared on abutment teeth afterwards, and the cast was turned into a metal master cast to serve as a reference cast. Twenty RPD samples were made, ten samples for the Co-Cr group and ten for the PEEK group. A Vinyl Polysiloxane(VPS) is used to paint the intaglio surface of the rest, and the frame samples are held in place with finger pressure on the master cast. Eighty VPS samples were made to present the gap between rest and rest seats; these samples were measured using a digital micrometre under a microscope with a magnification of 40x. The data were analysed using SPSS programs with an independent T-test.

Results: comparison between the two groups revealed that the PEEK groups had a better fit in one tooth #17 with a mean of (147.2 µm) than the Co-Cr group (252.6 µm), which is statically significant with a P value of (0.000). The other three abutments showed no significant difference.

Conclusion: RPD frames made from PEEK showed a slightly better fit than Co-Cr frames.



Carr AB, Brown DT, Carr AB, McCracken WL. McCracken's removable partial prosthodontics: Thirteen editions. 2016.

Campbell SD, Cooper L, Craddock H, Hyde TP, Nattress B, Pavitt SH, et al. Removable partial dentures: The clinical need for innovation. J Prosthet Dent. 2017;118(3):273–80. :10.1016/j.prosdent.2017.01.008

Kola MZ, Raghav D, Kumar P, Alqahtani F, Murayshed MS, Bhagat TV. In vitro Assessment of Clasps of Cobalt-Chromium and Nickel-titanium Alloys in Removable Prosthesis. J Contemp Dent Pract. 2016 Mar 1;17(3):253–7. DOI: 10.5005/jp-journals-10024-1836

Carr AB, Brown DT. McCracken's removable partial prosthodontics: Twelfth edition. 2010.

Muller K, Valentine-Thon E. Hypersensitivity to titanium: clinical and laboratory evidence. Neuroendocrinol Lett. 2006;27(1):31–5.

Ohkubo C, Hanatani S, Hosoi T. Present status of titanium removable dentures–a review of the literature. J Oral Rehabil. 2008;35(9):706–14. DOI: 10.1111/j.1365-2842.2007.01821.x

Keltjens H, Mulder J, Käyser AF, Creugers NHJ. Fit of direct retainers in removable partial dentures after 8 years of use. J Oral Rehabil. 1997;24(2):138–42. DOI: 10.1046/j.1365-2842.1997.d01-266.x

Wiesli MG, Özcan M. High-performance polymers and their potential application as medical and oral implant materials: a review. Implant Dent. 2015;24(4):448–57. DOI:10.1097/ID.0000000000000285

Bathala L, Majeti V, Rachuri N, Singh N, Gedela S. The role of polyether ether ketone (PEEK) in dentistry–a review. J Med Life. 2019;12(1):5. DOI: 10.25122/jml-2019-0003

Zoidis P. The all-on-4 modified polyetheretherketone treatment approach: A clinical report. J Prosthet Dent. 2018;119(4):516–21. DOI: 10.1016/j.prosdent.2017.04.020

Stawarczyk B, Beuer F, Wimmer T, Jahn D, Sener B, Roos M, et al. Polyetheretherketone—a suitable material for fixed dental prostheses? J Biomed Mater Res B Appl Biomater. 2013;101(7):1209–16. DOI: 10.1002/jbm.b.32932

Bajunaid S, Altwaim B, Alhassan M, Alammari R. The fit accuracy of removable partial denture metal frameworks using conventional and 3D printed techniques: An in vitro study. J Contemp Dent Pr. 2019;20(4):476–81.

Doxtater LW. Full and partial denture prosthesis. Dental items of interest publishing Company, incorporated; 1936.

Heimer S, Schmidlin PR, Stawarczyk B. Discoloration of PMMA, composite, and PEEK. Clin Oral Investig. 2017 May;21(4):1191–200. DOI: 10.1007/s00784-016-1892-2

Veljee TM, Shruthi CS, Poojya R. Comparative evaluation of the fit of the partial denture framework fabricated from conventional casting wax and light cured pattern wax– an in vitro study. 2014;2(4): 8-12.

Murray MD, Dyson JE. A study of the clinical fit of cast cobalt-chromium clasps. J Dent. 1988 Jun;16(3):135–9. DOI: 10.1016/0300-5712(88)90008-5

Ahmed N, Abbasi MS, Haider S, Ahmed N, Habib SR, Altamash S, et al. Fit Accuracy of Removable Partial Denture Frameworks Fabricated with CAD/CAM, Rapid Prototyping, and Conventional Techniques: A Systematic Review. BioMed Res Int. 2021;2021:3194433. DOI: 10.1155/2021/3194433

Stern MA, Brudvik JS, Frank RP. Clinical evaluation of removable partial denture rest seat adaptation. J Prosthet Dent. 1985 May;53(5):658–62. DOI: 10.1016/0022-3913(85)90015-0

Negm EE, Aboutaleb FA, Alam-Eldein AM. Virtual Evaluation of the Accuracy of Fit and Trueness in Maxillary Poly(etheretherketone) Removable Partial Denture Frameworks Fabricated by Direct and Indirect CAD/CAM Techniques. J Prosthodont. 2019;28(7):804–10. DOI: 10.1111/jopr.13075

Shihabi S, Salloum A, Almohareb M, Maraka N. Evaluation of the Fit Accuracy of Removable Partial Denture Frameworks Fabricated Using Three Different Techniques: An In Vitro Study. 2021 Oct;8:4881–6. DOI: 10.19070/2377-8075-21000987

Schwitalla AD, Spintig T, Kallage I, Müller WD. Flexural behavior of PEEK materials for dental application. Dent Mater Off Publ Acad Dent Mater. 2015 Nov;31(11):1377–84. DOI: 10.1016/




How to Cite

Putros AY, Mikaeel JM. Comparison of fit of poly (etheretherketone) and cobalt-chromium removable partial denture frames: an in-vitro study. EDJ [Internet]. 2023 Jun. 30 [cited 2024 May 18];6(1):113-9. Available from:



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