A systematic review of force decay in orthodontic elastomeric power chains.
BACKGROUND
Elastomeric chains are one of several devices used to provide force for orthodontic tooth movement, but the force they exert diminishes over time and can thus be difficult to control. The objective of this investigation was to provide a systematic review of publications pertinent to force decay in orthodontic elastomeric chains.


METHODS
A systematic review was performed via electronic querying of multiple databases for the period 1970-2011. Queries were limited to a set of specific keywords in two languages (English and French). Five main reviews were consulted manually to identify relevant publications. Two investigators sorted out those studies that complied with selection criteria.


CONCLUSIONS
A total of 53 studies were found to be relevant to force decay in elastomeric chains, including 22 on force decay over time, seven on the force consequences of pre-stretching, 12 on the impact of the environment on the force delivered, and 11 on clinical efficacy.


CONCLUSIONS
The force delivered by elastomeric chains decays rapidly over time, affecting their mechanical properties and clinical efficacy when studied in either human saliva or laboratory test media.
University Mohammed V-Souissi (UM5S), Oral Biomechanics and Biotechnology Research Unit, Dentofacial Orthopedics Department, College of Dental Medicine, centre hospitalier Ibn-Sina, BP 6212, Rabat-Instituts, Madinat Al Irfane, Rabat, Morocco. halimiali111@yahoo.fr
Abdelali
A
Halimi
Hicham
H
Benyahia
Anas
A
Doukkali
Mohamed-Faouzi
MF
Azeroual
Fatima
F
Zaoui
D003799:Dental Stress Analysis; D020724:Elastomers / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D055595:Mechanical Phenomena; D009967:Orthodontic Appliances; D011140:Polyurethanes / Q000737:chemistry; D012463:Saliva; D013718:Tensile Strength; D013997:Time Factors
D020724:Elastomers; D011140:Polyurethanes