Direct bilayered biomimetic composite restoration: The effect of a cusp-supporting short fiber-reinforced base design on the chewing fracture resistance and failure mode of molars with or without endodontic treatment

Jasmina Bijelic-Donova; Filip Keulemans; Pekka K Vallittu; Lippo V J Lassila

doi:10.1016/j.jmbbm.2019.103554

Direct bilayered biomimetic composite restoration: The effect of a cusp-supporting short fiber-reinforced base design on the chewing fracture resistance and failure mode of molars with or without endodontic treatment

J Mech Behav Biomed Mater. 2020 Mar:103:103554. doi: 10.1016/j.jmbbm.2019.103554. Epub 2019 Nov 24.

Authors

Jasmina Bijelic-Donova¹, Filip Keulemans², Pekka K Vallittu³, Lippo V J Lassila²

Affiliations

¹ Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, 20520, Turku, Finland; Department of Biomaterials Science, Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, 20520, Turku, Finland; Turku Clinical Biomaterials Centre (TCBC), Institute of Dentistry, University of Turku, Itäinen Pitkäkatu 4B, 20520, Turku, Finland. Electronic address: jabije@utu.fi.
² Department of Biomaterials Science, Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, 20520, Turku, Finland; Turku Clinical Biomaterials Centre (TCBC), Institute of Dentistry, University of Turku, Itäinen Pitkäkatu 4B, 20520, Turku, Finland.
³ Department of Biomaterials Science, Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, 20520, Turku, Finland; Turku Clinical Biomaterials Centre (TCBC), Institute of Dentistry, University of Turku, Itäinen Pitkäkatu 4B, 20520, Turku, Finland; City of Turku Welfare Division, Oral Health Care, Lemminkäisenkatu 2, 20520, Turku, Finland.

PMID: 32090948
DOI: 10.1016/j.jmbbm.2019.103554

Abstract

The aim of this study was to assess the chewing fracture resistance of compromised molars restored with direct composite resin (CR) restorations, with and without a short-fiber reinforcing (short-FRC) base. Wide extension of MOD cavities with removed palatal cusps preparations were simulated on 48 extracted maxillary molars. Five groups (n = 12) were designed: 1. control (intact teeth), 2. non-endodontically treated and 3. endodontically treated teeth with direct CR restorations (GC-Posterior), and 4. non-endodontically treated and 5. endodontically treated teeth with direct biomimetic bilayered restorations. Groups 4 and 5 included an anatomically shaped short-FRC base (everX Posterior), covered with a 2 mm CR layer (GC-Posterior). Restorations were subjected to chewing in water (1.5 Hz), with load of 85 N. Specimens were loaded until fracture or to a maximum of 120 000 cycles. Restorations that survived the chewing cycle were submitted to static load test (post-chewing test). The data were statistically analyzed using two-way ANOVA (p = 0.05) and fracture types with the chi-square test (p = 0.05). Fractures were classified into reparable, possibly reparable or non-reparable. All specimens survived the chewing cycle. The chewing fracture resistance of the direct biomimetic restorations prepared on non-endodontically treated teeth (2889 N) was statistically significantly higher than the direct CR counterparts (1966 N) (p = 0.00015), which was not the case for the groups with endodontically treated teeth (p = 0.257). Inclusion of a short-FRC base also influenced the fracture type resulting in most reparable fractures (67-75% versus 25% for biomimetic and CR groups respectively) (p = 0.054). Anatomically shaped i.e. a cusp-supporting design made of short-FRC base (everX Posterior) improved the chewing fracture resistance and fracture manner of compromised molars regardless of whether they were endodontically treated or not.

Keywords: Anatomical cusp design; Bilayered structure; Biomimetic; Chewing; Fiber-reinforced composite; Fracture strength.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Biomimetics
Composite Resins
Dental Restoration, Permanent
Dental Stress Analysis
Humans
Mastication
Molar
Tooth Fractures* / therapy
Tooth, Nonvital*

Substances

Composite Resins