IADR Abstract Archives
Dimensions and mechanical properties of latex and non-latex orthodontic elastics
Objectives: The purpose of this study were to compare dimensional characteristics and mechanical properties of latex and non-latex orthodontic elastics for orthodontic application.
Methods:
60 samples ( 30 latex and 30 non-latex ) of orthodontic elastics of heavy (6 oz.) force with 3/16 inch diameter from American Orthodontics were used in this study. The cross-sectional thickness and cross-sectional area were measured by a measuring microscope before they were mechanically tested. A Universal Testing Machine was used to test the mechanical properties which included
The initial extension force produced (F0) was measured when the elastic was kept stretched to 3 times its diameter for 30 ± 2 s at room temperature with the crosshead speed of 100±10 mm/ min. The stretched elastic were then transferred without relaxation onto the supportive plate in water at 37± 2°C for 24±2 h. The samples were taken out of water and transferred without relaxation to test for the residual force (F24). The percentage of force loss was then calculated.
Results:
Significant differences of dimensional characteristics and mechanical properties were found between latex and non-latex orthodontic elastics. For the dimension, it was found that non-latex elastics had greater thickness than latex type. However, the initial force produced from both group was not significantly different. In terms of force decay, non-latex elastics showed significantly higher level of percentage of force loss (38.52%) when compared with latex elastics (29.38%) after 24hours. The difference in force loss between latex and non-latex elastics could be due to the different structure of the polymers.
Conclusions:
Non-latex elastics had greater thickness than latex type. In terms of force decay after 24hours, non-latex elastics showed higher level of force loss when compared with latex elastics.
Methods:
60 samples ( 30 latex and 30 non-latex ) of orthodontic elastics of heavy (6 oz.) force with 3/16 inch diameter from American Orthodontics were used in this study. The cross-sectional thickness and cross-sectional area were measured by a measuring microscope before they were mechanically tested. A Universal Testing Machine was used to test the mechanical properties which included
The initial extension force produced (F0) was measured when the elastic was kept stretched to 3 times its diameter for 30 ± 2 s at room temperature with the crosshead speed of 100±10 mm/ min. The stretched elastic were then transferred without relaxation onto the supportive plate in water at 37± 2°C for 24±2 h. The samples were taken out of water and transferred without relaxation to test for the residual force (F24). The percentage of force loss was then calculated.
Results:
Significant differences of dimensional characteristics and mechanical properties were found between latex and non-latex orthodontic elastics. For the dimension, it was found that non-latex elastics had greater thickness than latex type. However, the initial force produced from both group was not significantly different. In terms of force decay, non-latex elastics showed significantly higher level of percentage of force loss (38.52%) when compared with latex elastics (29.38%) after 24hours. The difference in force loss between latex and non-latex elastics could be due to the different structure of the polymers.
Conclusions:
Non-latex elastics had greater thickness than latex type. In terms of force decay after 24hours, non-latex elastics showed higher level of force loss when compared with latex elastics.