Evaluation of Force Decay in Intraoral Elastics With Different Lumen Sizes: An In Vitro Study

Orthodontic elastics are routinely used for molar correction and space closure; however, their clinical efficiency may be compromised by gradual force degradation. Since elastics of different lumen sizes may be prescribed sequentially for the same patient, assessing their stability and the influence of mouthwash exposure is clinically relevant.

Latex intraoral elastics (OSL Orthodontic Intraoral Elastics) of five different lumen sizes (1/8", 3/16", 1/4", 5/16", and 3/8"), each designed to deliver 3.5 oz of force, were tested. Fifty samples were divided into two groups: Group A (stored in artificial saliva) and Group B (treated with chlorhexidine mouthwash at predetermined intervals). The elastics were extended to three times their lumen size using custom jigs. Force values were recorded at baseline, one, three, 12, and 24 hours using a digital gauge, and the percentage of force decay was calculated. Data were analyzed using one-way analysis of variance (ANOVA) and independent t-tests, with p < 0.05 as the criterion for significance.

All elastics demonstrated progressive force decay over time. Larger lumen elastics (A3 and A4) maintained force more effectively, whereas smaller lumen sizes (A1 and A2) exhibited greater force loss, particularly at 12-24 hours. Mouthwash exposure produced variable effects, with significant differences observed among selected elastics at specific intervals.

Lumen size plays a critical role in the force decay of intraoral elastics, with smaller lumen elastics showing earlier and greater force loss. Mouthwash exposure inconsistently alters this pattern, emphasizing the need for careful patient selection and guidance in clinical practice.