Fatigue rupture study of HL-3 Buccal Multiloops for simulation of oral movements

Pan Yu; Hou Lu; Xu Shi-qian

doi:10.3969/j.issn.2095-4344.2013.38.007

Abstract：BACKGROUND:Concerning the problem of the ruptured phenomenon in clinic work of HL-1 and HL-2 Buccal Multiloops removable appliance, we invented HL-3 Buccal Multiloops. <br> OBJECTIVE:Through the Buccal Multiloops Fatigue Testing Machine which can imitate oral movements, to compare the fatigue strength of the HL-2 and HL-3 Buccal Multiloops in the same condition. <br> METHODS:A pair of the HL-2 or HL-3 Buccal Multiloops with the completely symmetrical size, symmetrical height and symmetrical direction was fixed on the Buccal Multiloops Fatigue Testing Machine which could simulate oral movements, then keep the Buccal Multiloops Fatigue Testing Machine working until any Buccal Multiloops broke. The cyclic loading times of this pair Buccal Multiloops was recorded. Scanning electron microscope was used to observe the appearance of broken end of the Buccal Multiloops. <br> RESULTS AND CONCLUSION:The cyclic loading times of HL-3 Buccal Multiloops were more than HL-2 Buccal Multiloops (P < 0.01), suggesting that HL-3 Buccal Multiloops has stronger fatigue strength than HL-2 Buccal Multiloops. Scanning electron microscope observation showed that the fractures of HL-2 and HL-3 Buccal Multiloops al had the typical fatigue fracture morphology, indicating that the rupture of HL-2 and HL-3 Buccal Multiloops belongs to fatigue fracture. However, HL-3 Buccal Multiloops exhibited bigger crack compared with HL-2 Buccal Multiloops, the presence of running-in region, suggesting that HL-3 Buccal Multiloops reduced the probability of fatigue fracture and prolonged the time of fatigue fracture.