J Korean Acad Prosthodont.  2019 Apr;57(2):127-133. 10.4047/jkap.2019.57.2.127.

Evaluation of static fracture resistances and patterns of pulpless tooth restored with poly-ether-ketone-ketone (PEKK) post

• Park HE
• Lee CW
• Lee WS
• Yang SE
• Lee SY

• KMID: 2444181
• DOI: http://doi.org/10.4047/jkap.2019.57.2.127

Abstract

PURPOSE
The purpose of present study was to investigate fracture strength and mode of failure of endodontically treated teeth restored with metal cast post-core system, prefabricated fiber post system, and newly introduced polyetherketoneketone (PEKK) post-core system.
MATERIALS AND METHODS
A total of 21 mandibular premolar were randomly grouped into 3 groups of 7 each according to the post material. Group A was for metal cast post core; Group B for prefabricated glass fiber post and resin core; and Group C for milled PEKK post cores. All specimens were restored with metal crown. The fracture strength of each specimen was measured by applying a static load of 135-degree to the tooth at 2 mm/min crosshead speed using a universal testing machine. After the fracture strength measurement, the mode of failure was observed. The results were analyzed using Kruscal-Wallis test and post hoc Mann-Whitney U test at confidence interval α = .05.
RESULTS
Fracture resistance of PEKK post core was lower than those of cast metal post and fiber reinforced post with composite resin core. In the aspect of fracture mode most of the root fracture occurred in the metal post core, whereas the post detachment occurred mainly in the fiber reinforced post. In the case of PEKK post core, teeth and post were fractured together.
CONCLUSION
It is necessary to select appropriate materials of post for extensively damaged teeth restoration and clinical application of the PEKK post seems to require more research on improvement of strength.

Keyword

Polyetherketoneketone (PEKK); Post; Fracture resistance; Fracture mode

MeSH Terms

Bicuspid
Crowns
Glass
Tooth
Tooth, Nonvital*

Figure

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  Fig. 1 Schematic dimensions of post, core and crown for each group. Group A, metal cast post and core; Group B, prefabricated glass fiber post core; Group C, PEKK milled post and core.

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  Fig. 2 Specimen configuration for load test on universal testing machine.

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  Fig. 3 Representative X-ray images of failure mode for each group. (A) Group A: root fracture, (B) Group B: post debonding, (C) Group C: root and post fracture.

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