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Surface characteristics and ion leaching of 17-4 precipitation hardening stainless steel orthodontic brackets exposed to salt water and fluoride-based oral rinses

Bangalore Durgesh, Alhassoun Raghad, Alaqeel Samer M., Alsadon Omar, Alshahrani Obaid A., Alsarani Majed M., Alsharif Maymoonah, Matinlinna Jukka Pekka

Materials Science Poland

2025

Vol. 43, No. 2

113--126

The aim of this laboratory study is to analyze, compare, and contrast qualitatively and quantitatively the surface roughness and metal ion leaching of two brands of orthodontic precipitation hardening 17-4 stainless steel (SS) brackets exposed to salt water and commercially available NaF-based oral rinses. A total of 60 SS maxillary premolar orthodontic brackets from two brands (Victory Series™, and Mini Diamond Twin™) were assigned to three groups (n = 10). The brackets were immersed in NaF-containing oral rinses (Listerine™ or Orex™), or salt water rinse for 28 days. Microhardness (Vickers hardness number, VHN) and surface roughness (Ra) before and after immersion in oral rinses were evaluated using a non-contact optical profilometer. Inductively coupled plasma mass spectrometry (ICP-MS) was used to analyze the ion leaching into oral rinses. The local surface changes and elemental analysis of corrosion-free and corrosion spots after immersion were assessed and compared using scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (EDS). Data analysis was performed using Statistical Package for the Social Sciences software using one-way analysis of variance, the Tukey’s post hoc test, and paired t-test (α = 0.05). The VHN of the brackets was significantly different at baseline and after immersion in the oral rinses (P < 0.05). The mean Ra before immersion in oral rinses for the two groups of the orthodontic brackets was significantly different (P < 0.01). The brackets immersed in salt water for Victory™ (0.65 ± 0.07 µm) and Mini Diamond™ (0.76 ± 0.08 µm) demonstrated significantly lower roughness values than NaF-based oral rinses (Listerine™ or Orex™) (P < 0.01). However, the difference in Rabetween the bracket systems was significant only for Listerine™ and Orex™ rinses (P > 0.01). The ICP-MS analysis showed significant differences for Cu and Zn ions in Listerine™ and all ions except Ni for salt water oral rinses. On the contrary, the comparison between the bracket systems for the metal ions showed no significant difference in the Orex™ group (P > 0.05). Salt water oral rinses demonstrated significantly fewer surface changes than NaF-containing oral rinses. The leaching of the metal ions was significant for Fe2+ and Cr3+ but did not vary considerably for Ni2+ between the evaluated oral rinses.

Effect of conventional and digital methods and aging on the shear bond strength of orthodontic brackets with temporary crowns based on aged PMMA

Alsarani Majed M., Bangalore Durgesh, Alfrisany Najm, Alshamrani Abdullah A., El-Bialy Tarek

Polimery

2024

Vol. 69, nr 10

577--589

Shear bond strength (SBS) of orthodontic brackets bonded to temporary crowns (TC) was investigated. TC were manufactured using conventional and digital methods (CAD/CAM milling, 3D printing) and then subjected to cyclic aging (5 000 cycles). Surface roughness (Ra) and contact angle of polished and abrasive blasted TC were determined before and after aging. Data analysis was performed using one-way ANOVA and repeated measures, and LSD in post-hoc tests (α=0.05). After surface treatment, there was a significant increase in Ra of conventional and milled TC (p<0.001), while 3D printed showed a slight increase in Ra (p=0.073). The contact angle of polished TC surfaces was significantly different (p>0.05), and after surface treatment the differences in contact angle were small (p<0.001). Aesthetic orthodontic brackets bonded to temporary crowns, regardless of the production method, have adequate bond strength before and after aging, with the exception of 3D printed TCs after aging.

Zbadano wytrzymałość na ścinanie (SBS) zamków ortodontycznych przyklejonych do koron tymczasowych (TC). TC wykonano metodami konwencjonalnymi i cyfrowymi (frezowanie CAD/ CAM, druk 3D), a następnie poddano cyklicznemu starzeniu (5000 cykli). Oznaczono chropowatość powierzchni (Ra) i kąt zwilżania polerowanych i poddanych obróbce strumieniowo-ściernej TC, przed i po starzeniu. Do analizy danych zastosowano metodę A NOVA jednokierunkową i powtarzanych pomiarów oraz LSD w testach post-hoc (α=0,05). Po obróbce powierzchniowej nastąpił istotny wzrost Ra konwencjonalnych i frezowanych TC (p<0,001), a drukowane w 3D wykazały niewielki wzrost Ra (p=0,073). Kąt zwilżania polerowanych powierzchni TC różnił się istotnie (p>0,05), a po obróbce powierzchni różnice kąta zwilżania były niewielkie (p<0,001). Estetyczne zamki ortodontyczne przyklejone do koron tymczasowych niezależnie od metody otrzymywania mają odpowiednią wytrzymałość wiązania przed i po starzeniu, z wyjątkiem TC drukowanych w 3D po starzeniu.