Shrinkage stress compensation in composite-restored teeth: Relaxation or hygroscopic expansion?

Laurel A. Meriwether, Bernard Blen, Jarred H. Benson, Robert Hatch, Daranee Versluis, Antheunis Versluis

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Objectives: Polymerization of composite restorations causes shrinkage, which deforms and thus stresses restored teeth. This shrinkage deformation, however, has been shown to decrease over time. The objective was to investigate whether this reduction was caused by hygroscopic expansion or stress relaxation of the composite/tooth complex. Methods: Extracted molars were mounted in rigid stainless steel rings with four spherical reference areas. Twelve molars were prepared with large mesio-occluso-distal slots, etched, bonded, and restored with a composite material (Filtek Supreme, 3M ESPE) in two horizontal layers. Ten intact molars were the controls. The teeth were stored either in deionized water or silicone oil. They were scanned after preparation (baseline), restoration (0-week), and after 1, 2, and 4 weeks storage. Scanned tooth surfaces were aligned with the baseline using the unchanged reference areas. Cuspal flexure was calculated from lingual and buccal surface deformation. To verify that the restorations had remained bonded, dye penetration at the interfaces was assessed using basic fuchsin dye. Statistical assessment was done by ANOVA followed by Student-Newman-Keuls post hoc test (p = 0.05). Results: Substantial cuspal contraction was found for restored teeth after the composite was cured (13-14 μm cuspal flexure). After 4 weeks cuspal contraction decreased significantly for restored teeth stored in water (7.3 ± 3.2) but not for those stored in silicone oil (11.4 ± 5.0). Dye penetration of the occlusal interface was minimal in both groups (106 ± 87 and 21 ± 28 μm in water and silicone oil, respectively). Significance: The results suggest that hygroscopic expansion was the main mechanism for shrinkage stress compensation.

Original languageEnglish (US)
Pages (from-to)573-579
Number of pages7
JournalDental Materials
Volume29
Issue number5
DOIs
StatePublished - May 1 2013

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Tooth
Silicone Oils
Silicones
Composite materials
Restoration
Coloring Agents
Dyes
Water
Deionized water
Stainless Steel
Stress relaxation
Analysis of variance (ANOVA)
Cheek
Tongue
Polymerization
Stainless steel
Compensation and Redress
Students
Analysis of Variance
Oils

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Dentistry(all)
  • Mechanics of Materials

Cite this

Shrinkage stress compensation in composite-restored teeth : Relaxation or hygroscopic expansion? / Meriwether, Laurel A.; Blen, Bernard; Benson, Jarred H.; Hatch, Robert; Versluis, Daranee; Versluis, Antheunis.

In: Dental Materials, Vol. 29, No. 5, 01.05.2013, p. 573-579.

Research output: Contribution to journalArticle

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