Document Detail

Resistance to sliding of orthodontic appliances in the dry and wet states: influence of archwire alloy, interbracket distance, and bracket engagement.
MedLine Citation:
PMID:  11033563     Owner:  NLM     Status:  MEDLINE    
Having established dimensional and mechanical characteristics, the resistances to sliding (RS) were measured in vitro for various archwires against stainless steel brackets. Using stainless steel ligatures, a constant normal force (300g) was maintained while second-order angulation (straight theta) was varied from -12 degrees to +12 degrees. Using miniature bearings to simulate contiguous teeth, five experiments each were run in the dry or wet states with human saliva at 34 degrees C as a function of four archwire alloys, five interbracket distances, and two bracket engagements. Outcomes were objectively analyzed to establish when theta=0, and the relative contact angles ( theta(r)) were replotted. Critical contact angles (theta(c)) that were determined via experimentation were in good agreement with theory. Slopes and y-intercepts were tabulated from linear regression equations of RS against theta plots in both the passive (theta < or = theta (c)) and active ( theta > or = theta(c)) configurations, for which theta = theta(c) identified the boundary between classical friction and binding phenomena. Stiffer archwires and shorter interbracket distances exacerbated binding, whereas, once corrected for differing bracket engagement, RS was independent of slot dimension. Unlike earlier results in the passive configuration, in the active configuration couples comprised of titanium alloys (NiTi and (beta-Ti) had higher RS values in the wet versus the dry state. For those archwire alloys evaluated, two empirical expressions were adduced that comprise the binding component, the yield strength or elastic limit, and the beam length, which implicitly represent the stiffness, flexibility, and interbracket distance.
R P Kusy; J Q Whitley
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Publication Detail:
Type:  Comparative Study; Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of biomedical materials research     Volume:  52     ISSN:  0021-9304     ISO Abbreviation:  J. Biomed. Mater. Res.     Publication Date:  2000 Dec 
Date Detail:
Created Date:  2000-12-01     Completed Date:  2000-12-01     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0112726     Medline TA:  J Biomed Mater Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  797-811     Citation Subset:  IM    
Copyright Information:
Copyright 2000 John Wiley & Sons, Inc.
Dental Research Center, University of North Carolina, Building 210H, Room 313, CB#7455, Chapel Hill, North Carolina 27599-7455, USA.
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MeSH Terms
Dental Alloys / chemistry*
Equipment Design
Materials Testing
Nickel / chemistry*
Orthodontic Brackets*
Orthodontic Wires*
Stainless Steel / chemistry*
Titanium / chemistry*
Reg. No./Substance:
0/Dental Alloys; 0/beta titanium; 12035-60-8/titanium nickelide; 12597-68-1/Stainless Steel; 7440-02-0/Nickel; 7440-32-6/Titanium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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