Physical properties of conventional and Super Slick elastomeric ligatures after intraoral use.
OBJECTIVE
To investigate the change in the physical properties of conventional and Super Slick elastomeric ligatures after they have been in the mouth.


METHODS
Nine healthy volunteers took part. One orthodontic bracket was bonded to a premolar tooth in each of the four quadrants of the mouth. Two conventional and two Super Slick elastomeric ligatures were placed at random locations on either side of the mouth. The ligatures were collected after various time intervals and tested using an Instron Universal testing machine. The two outcome measures were failure load and the static frictional resistance.


RESULTS
The failure load for conventional ligatures was reduced to 67% of the original value after 6 weeks in situ. Super Slick elastomeric ligatures showed a comparable reduction after 6 weeks in situ (63% of original value). There were no statistical differences in the static friction between conventional and Super Slick elastomerics that had been in situ for either 24 hours (P = .686) or 6 weeks (P = .416). There was a good correlation between failure load and static friction (r = .49).


CONCLUSIONS
There were statistically significant differences in the failure loads of elastomerics that had not be placed in the mouth and those that had been in the mouth for 6 weeks. There were no differences in the static frictional forces produced by conventional and Super Slick ligatures either before or after they had been placed in the mouth. There appears to be a direct proportional relationship between failure load and static friction of elastomeric ligatures.
Department of Orthodontics, Charles Clifford Dental Hospital, South Yorkshire, Sheffield, UK. nicky.crawford@yahoo.co.uk
Nicola Louise
NL
Crawford
Caroline
C
McCarthy
Tanya C
TC
Murphy
Philip Edward
PE
Benson
D000328:Adult; D001641:Bicuspid; D020724:Elastomers / Q000737:chemistry*; D004868:Equipment Failure; D017276:Friction; D006801:Humans; D008422:Materials Testing; D055595:Mechanical Phenomena; D008875:Middle Aged; D009055:Mouth / Q000502:physiology*; D009967:Orthodontic Appliances; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013997:Time Factors; D055815:Young Adult
D020724:Elastomers; D013193:Stainless Steel