Fatigue behavior of dental resin composites: flexural fatigue in vitro versus 6 years in vivo.

Abstract

OBJECTIVES:

To evaluate fatigue behavior of direct resin composite restorations (Tetric Ceram vs. Grandio) in vitro and in vivo over an observation period of 6 years.

METHODS:

For the in vitro part, Young's moduli (YM) were calculated and both initial (FS: flexural strength) and fatigue flexural strength (FFL: flexural fatigue limit) were evaluated in a four-point bending setup (n = 15) in distilled water at 37°C. For the in vivo part, 30 patients received 68 direct resin composite restorations of the same materials (Grandio bonded with Solobond M; Tetric Ceram bonded with Syntac). Patients revealed a minimum of two different class II restorations in different quadrants. Epoxy replicas of restored teeth were analyzed under a scanning electron microscope (SEM) at 30× magnification for fatigue characteristics, and 11 selected restorations per group were assessed for marginal fatigue characteristics at 200×.

RESULTS:

In vitro, YM was 15.7 GPa (Grandio) and 8.7 GPa (Tetric Ceram; p < 0.05), FS was 115.0 MPa (Grandio) versus 101.5 MPa (Tetric Ceram; p > 0.05), and FFL was 63.0 MPa (Grandio) versus 44.3 MPa (Tetric Ceram; p < 0.05). In vivo, no significant difference in fatigue behavior (cracks, chippings) was evaluated for the different materials under investigation. However, marginal breakdown was more pronounced under the SEM for Tetric Ceram (7.9% vs. 4.8% for Grandio; p < 0.05), but without being clinically relevant. SEM analysis exhibited distinct wear patterns after 6 years with no significant differences among materials as well.

SIGNIFICANCES:

Despite higher in vitro values for YM, FS, and FFL for Grandio, clinical outcome for both resin composite materials over 6 years of clinical service was similar. Higher FFLs in vitro seem to be related to less marginal composite fractures in vivo but without any influence on clinical outcome until the 6 years recall.

• Authors: Franklin Garcia-Godoy, Roland Frankenberger, Ulrich Lohbauer, Albert J Feilzer, Norbert Krämer
• Journal: Journal of biomedical materials research. Part B, Applied biomaterials (J Biomed Mater Res B Appl Biomater) Vol. 100 Issue 4 Pg. 903-10 (May 2012) ISSN: 1552-4981 [Electronic] United States
• PMID: 22323387 (Publication Type: Journal Article, Randomized Controlled Trial)
• Copyright: Copyright © 2012 Wiley Periodicals, Inc.

Chemical References

• Acrylic Resins
• Biocompatible Materials
• Composite Dental Resin
• Composite Resins
• Grandio
• Polyurethanes
• Tetric ceram

Topics

• Acrylic Resins (chemistry)
• Adult
• Biocompatible Materials (chemistry)
• Composite Resins (chemistry)
• Elastic Modulus
• Female
• Humans
• In Vitro Techniques
• Male
• Microscopy, Electron, Scanning (methods)
• Middle Aged
• Models, Statistical
• Polyurethanes (chemistry)
• Pressure
• Stress, Mechanical
• Temperature
• Time Factors
• Tooth (physiology)