Mechanical deterioration of passive self-ligating lingual brackets under simulated prolonged use: An in vitro study
Prasad Nalabothu, Konstantina Papadopoulou, Michel Dalstra, Giuseppe Scuzzo, Carlalberta Verna · 2025 · 0 citationsRead the paper
<h2>ABSTRACT</h2><h3>Background</h3> Passive, self-ligating lingual brackets are favored in Orthodontics for their simplified mechanism, eliminating the need for elastomeric and metallic ligatures. However, limited data exists on the effects of repeated use on their mechanical durability. An understanding of these effects is essential to ensure their long-term clinical performance. This study evaluates the mechanical degradation of the sliding cap locking mechanism of passive self-ligating lingual brackets after repeated opening and closing cycles. <h3>Methods</h3> In this in vitro study, 60 ALIAS mandibular incisor brackets were subjected to repeated opening and closing cycles (5, 10, 20, and 40 cycles). Mechanical tests were performed using an Instron 3344 electronic universal testing machine to measure maximum force at failure (<i>F</i><sub>max</sub>), energy absorption at <i>F</i><sub>max</sub> (<i>U</i><sub>max</sub>), and initial stiffness of the bracket opening mechanism (<i>K</i>). <h3>Results</h3> The sliding cap remained functional throughout the test period. However, a significant reduction in <i>F</i><sub>max</sub>, <i>U</i><sub>max,</sub> and <i>K</i> over multiple opening and closing cycles. <i>F</i><sub>max</sub> showed a significant reduction after 5 opening and closing cycles (<i>P</i> = 0.0069), <i>U</i><sub>max</sub> after 10 cycles (<i>P</i> = 0.0243), and <i>K</i> showed after 5 cycles (<i>P</i> = 0.0002). The <i>F</i><sub>max</sub> reached a plateau at about 8–10 Newtons after 10 cycles, <i>U</i><sub>max</sub> at about 2.0 mJ (millijoules), and <i>K</i> at 50 N/mm after 10 cycles. <h3>Conclusions</h3> The study highlights significant advantages of passive self-ligating lingual brackets, showcasing their excellent initial performance. While ALIAS brackets may experience minor mechanical deterioration of the properties, their overall performance remains strong enough for entire duration of orthodontic treatment (2–3 years).
2 ideas Seedlabs derived from this research
A redesigned sliding-cap locking mechanism using fatigue-resistant alloys/coatings engineered to hold its closing force and stiffness over the full 2–3 year treatment, addressing the measured drop-off after the first handful of open/close cycles.
AI score 55/100An independent in-vitro testing lab and certification standard that subjects self-ligating orthodontic brackets to repeated open/close cycling and reports how their locking mechanism degrades, giving manufacturers and clinicians comparable durability data.
AI score 54/100