An Invitro Compariosn of the Expansive Forces of Clear Aligners & Quadhelix Expanders

In this session we will provide a brief overview of the transverse expansion forces generated by different types of thermo-formed aligners: Zendura FLX® 0.030” (ZenduraDental, CA), Essix Ace® 0.030” and 0.035" (Dentsply Sirona, NC) and Invisalign ® (Align Technology, CA) and compare them to quadhelix expanders (RMO, IN). Experiments were performed in a 37° C water bath to mimic the intraoral environment. Samples underwent 4 two-hours stress-relaxation cycles separated by 15 minutes breaks. Initial force, force decay, energy and fatigue were measured and compared. Results show considerable force decay in aligners compared to the quahdhelix expanders. Differences between the aligner groups were also found.