Date of Award
Spring 1-1-2013
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Dentistry
First Advisor
Berzins, David
Second Advisor
Bradley, T. Gerard
Third Advisor
Bosio, Jose A.
Abstract
INVESTIGATION OF FORCE DECAY IN ESTHETIC COMPOSITE ORTHODONTIC ARCHWIRESJacob Spendlove, D.D.S.Marquette University, 2013
Introduction:Fiber-reinforced composite archwires have been developed to increase the esthetics of orthodontic appliances. Because polymer containing composites typically exhibit time-dependent stress-strain behavior, deflected fiber-reinforced composite archwires may experience a decrease in force over time. The goal of this research was to determine if esthetic fiber-reinforced composite archwires can maintain continuous light forces without undergoing extreme amounts of force decay.
Materials and Methods:Force decay was evaluated by comparing results of 3-point bending tests of nickel-titanium (NiTi) and fiber-reinforced composite archwires. Due to the impracticality of measuring force decay of a single archwire for 30 days, the following protocol was used: each segment was tested in 3-point bending using a universal testing machine to a maximum deflection of 3.1 mm; next, each segment was placed in a custom-made jig designed to deflect each segment either 1 or 2 mm for 30 days. Each segment was once again tested in 3-point bending to examine consistency of the bending profile. Paired t-tests were used to statistically compare pre- and post-deflection forces. A control group consisting of wires not subject to the 30 day constant deflection was tested to ensure that the initial testing did not alter the second 3-point bend test.
Results:Statistically significant (p
Conclusions:The BioMers 1 mm deflection group demonstrated that fiber-reinforced composite archwires are able to deliver a consistent force after 30 days of deflection. However, the clinical applicability of these fiber-reinforced composite archwires may be limited as they are unable to sustain deflections of 2 mm without experiencing crazing and loss of force delivery.