Static and fatigue fracture resistances of pulpless teeth restored with post–cores

Hayashi, Mikako; Sugeta, Atsushi; Takahashi, Yutaka; Imazato, Satoshi; Ebisu, Shigeyuki

doi:10.1016/j.dental.2008.01.009

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Volume 24, Issue 9 , Pages 1178-1186, September 2008

Static and fatigue fracture resistances of pulpless teeth restored with post–cores

Mikako Hayashi
- Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
- Corresponding author. Tel.: +81 6 6879 2927; fax: +81 6 6879 2928.
Atsushi Sugeta
- Department of Mechanical System Engineering, Graduate School of Engineering, Hiroshima University, Higashi-hiroshima, Hiroshima, Japan
Yutaka Takahashi
- Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
Satoshi Imazato
- Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
Shigeyuki Ebisu
- Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan

Received 6 March 2007; received in revised form 22 January 2008; accepted 22 January 2008.

Abstract

Objectives

Superior restorative methods for effectively strengthening pulpless teeth need to be identified, since vertical root fractures of pulpless teeth are still a major problem in everyday clinical practice. The present study tested the null hypothesis that there were no differences in static and fatigue fracture resistances of pulpless teeth restored with different types of post–core systems.

Methods

Extracted human premolars were restored with a combination of either a fiber post or metallic post and a composite resin core. Teeth with full crown preparations without post–core restorations served as a control. A 90° vertical or 45° oblique static compressive load was applied to restored teeth, and fracture loads and modes of fracture were recorded. Fatigue fracture tests were conducted by applying sinusoidal cyclic loads to restored teeth from vertical or oblique directions. Fatigue limits for each restoration were calculated using the staircase approach.

Results

In both static and fatigue fracture testing under vertical or oblique loadings, the fracture loads of teeth restored with fiber posts were significantly greater than those of teeth restored with metallic posts. The fatigue limits of teeth restored with fiber and metallic posts were 112kgf and 82kgf respectively under vertical loadings and 26kgf and 20kgf under oblique loadings.

Significance

The combination of a fiber post and a composite resin core showed superior fracture resistance against both static and fatigue loadings compared to restorations using a metallic post, and is therefore recommended in restoring pulpless teeth.

Keywords: Composite resin, Core, Fiber post, Metallic post, Fatigue fracture, Static fracture, Fracture resistance