The effects of increasing the reverse curve of Spee in a lower archwire examined using a dynamic photo-elastic gelatine model.
This paper describes the development and testing of a dynamic in vitro photo-elastic model for evaluating the effects of orthodontic mechanics on an entire arch of teeth. A model of a mandibular arch was made and the teeth were embedded in a gelatine material with a high level of mechanical creep which permitted tooth movement in response to orthodontic forces. The excellent photo-elastic properties of this material also facilitated the analysis of the stress distribution around the roots of the teeth. The model of a mandibular arch was used to investigate the tooth movements and stress distributions produced by increasing the reverse curve of Spee in a 0.018 x 0.025-inch stainless steel archwire. The results revealed that a 1-mm reverse curve of Spee increased the arch length by 1.6 mm, but increasing the reverse curve of Spee to 5 mm did not increase arch length further. Photo-elastic analysis showed an increased stress distribution around the roots of the incisors and molars as the reverse curve of Spee was increased in the archwire.
Clifford
P M
PM
Orthodontic Division, School of Clinical Dentistry, Queen's University of Belfast, UK.
Orr
J F
JF
Burden
D J
DJ
D001718:Birefringence; D002508:Cephalometry; D003724:Dental Arch / Q000033:anatomy & histology* / Q000502:physiology; D003799:Dental Stress Analysis / Q000379:methods*; D005780:Gelatin; D006801:Humans; D008310:Malocclusion / Q000628:therapy*; D008334:Mandible / Q000502:physiology; D008954:Models, Biological; D003765:Models, Dental; D009969:Orthodontic Wires; D014087:Tooth Movement Techniques
D005780:Gelatin