Indiana University-Purdue University Indianapolis (IUPUI) / Background: Interim restoration for a lost anterior tooth is often needed for
temporary esthetic and functional purposes. Materials for interim restorations usually
have less strength than ceramic or gold and can suffer from fracture. Several approaches
have been proposed to reinforce interim restorations, among which fiber reinforcement
has been regarded as one of the most effective methods. However, some studies have
found that the limitation of this method is the poor polymerization between the fibers and
the composite resin, which can cause debonding and failure.
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Purpose: The purpose of this study was to investigate the effects of different
polymerization methods as well as fiber types on the mechanical behavior of fiberreinforced
composite resin.
Material and Methods: A 0.2-mm thick fiber layer from strip fibers or mesh fibers
embedded in uncured monomers w as fabricated with polymerization (two-step method)
or without polymerization (one-step method), on top of which a 1.8-mm composite layer
was added to make a bar-shape sample, followed by a final polymerization. Seventy-five
specimens were fabricated and divided into one control group and four experimental
groups (n=15), according to the type of glass fiber (strip or mesh) and polymerization
methods (one-step or two-step). Specimens were tested for flexural strength, flexural
modulus, and microhardness. The failure modes of specimens were observed by scanning
electron microscopy (SEM).
Results: The fiber types showed significant effect on the flexural strength of test
specimens (F = 469.48; p < 0.05), but the polymerization methods had no significant
effect (F = 0.05; p = 0.82). The interaction between these two variables was not
significant (F = 1.73; p = 0.19). In addition, both fiber types and polymerization steps
affected the flexural modulus of test specimens (F = 9.71; p < 0.05 for fiber type, and F =
12.17; p < 0.05 for polymerization method). However, the interaction between these two
variables was not significant (F = 0.40; p = 0.53). Both fiber types and polymerization
steps affected the Knoop hardness number of test specimens (F = 5.73; p < 0.05 for
polymerization method. and F = 349.99; p < 0.05 for fiber type) and the interaction
between these two variables was also significant (F = 5.73; p < 0.05). SEM images
revealed the failure mode tended to become repairable while fiber reinforcement was
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existed. However, different polymerization methods did not change the failure mode.
Conclusion: The strip fibers showed better mechanical behavior than mesh fibers
and were suggested for use in composite resin reinforcement. However, different
polymerization methods did not have significant effect on the strength and the failure
mode of fiber-reinforced composite
| Identifer | oai:union.ndltd.org:IUPUI/oai:scholarworks.iupui.edu:1805/6497 |
| Date | January 2015 |
| Creators | Huang, Nan-Chieh |
| Contributors | Chu, Tien-Min Gabriel, Hara, Anderson T., Brown, David T., Bottino, Marco C., Levon, John A. |
| Source Sets | Indiana University-Purdue University Indianapolis |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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