Corrosion of Nickel-Titanium Orthodontic Archwires in Saliva and Oral Probiotic Supplements

Abstract

ObjectivesThe aim of the study was to examine how probiotic supplements affect the corrosion stability of orthodontic archwires made of nickel-titanium alloy (NiTi).Materials and MethodsNiTi archwires (0.508x0.508 and having the length of 2.5 cm) were tested. The archwires (composition Ni=50.4%, Ti=49.6%) were uncoated, nitrified and rhodium coated. Surface microgeometry was observed by using scanning electron microscope and surface roughness was measured by profilometer through these variables: roughness average, maximum height and maximum roughness depth. Corrosion was examined by electrochemical method of cyclic polarisation.ResultsRhodium coated alloy in saliva has significantly higher general corrosion in saliva than nitrified alloy and uncoated alloy, with large effect size (p=0.027; η2=0.700). In the presence of probiotics, the result was even more pronounced (p<0.001; η2=0.936). Probiotic supplement increases general and localised corrosion of rhodium coated archwire and slightly decreases general corrosion and increases localised corrosion in uncoated archwire, while in the case of nitrified archwire the probability of corrosion is very low. The differences in surface roughness between NiTi wires before corrosion are not significant. Exposure to saliva decreases roughness average in rhodium coated wire (p=0.015; η2=0.501). Media do not significantly influence surface microgeometry in nitrified and uncoated wires.ConclusionProbiotic supplement affects corrosion depending on the type of coating of the NiTi archwire. It increases general corrosion of rhodium coated wire and causes localised corrosion of uncoated and rhodium coated archwire. Probiotic supplement does not have greater influence on surface roughness compared to that of saliva.

ICP-MS Assessment of Essential and Toxic Trace Elements in Foodstuffs with Different Geographic Origins Available in Romanian Supermarkets

“…This element is an essential nutrient involved in morphological functions, growth, and development, including germination, and is naturally present in plant organs. It is frequently associated with primitive systems, such as those in anaerobic bacteria [ 26 ]. Although it is not essential for humans, Ni has been studied for its potentially harmful effects on health [ 27 ].…”

Changes in mechanical properties of dental alloys induced by saliva and oral probiotic supplements

“…Previous research imply that probiotic supplement affects corrosion resistance and that the occurrence of general and localized corrosion is influenced by the type of coating of NiTi alloy [26]. It seems to influence general corrosion of rhodiumcoated alloy and causes localised corrosion of uncoated and rhodium-coated alloy.…”

“…Low hydrofluoric acid concentration decreases corrosion resistance while high concentration improves it [29]. It was previously reported that probiotic supplement does not change roughness of NiTi alloys compared to the effect of saliva alone [26], but the profilometer analysis method is inferior to the atomic force microscopy method used here [31].…”

Influence of probiotics on the periodontium, the oral microbiota and the immune response during orthodontic treatment in adolescent and adult patients (ProMB Trial): study protocol for a prospective, double-blind, controlled, randomized clinical trial

“…Corrosion of orthodontic archwires can occur due to saliva (composed of inorganic salts, organic and gastric acids) and/or biofilm properties (community of microorganisms attached to the surface of teeth and archwires) [ 94 ]. Studies analysed the effect of probiotics on corrosion of different types of archwires and orthodontic materials: nickel-titanium (NiTi) alloys (uncoated, nitrified and rhodium coated surface) [ 94 , 95 ], titanium and stainless steel (SS) [ 94 , 96 ]. A mixture of artificial saliva with dissolved L. reuteri Prodentis® DSM 17938 and ATCC PTA 5289 (BioGaia, BioGaia AB, Sweden) was shown to have less corrosive effects on an uncoated surface (BioForce Sentalloy®, Dentsply International GAC, United States), comparable effects on nitrified surfaces and higher local and general corrosive side effects on rhodium coated surfaces compared to artificial saliva alone, indicating that surface roughness induced by probiotic was not greater than induced by saliva [ 95 ].…”