Effects of the presence of probiotic bacteria in the aging medium on the surface roughness and chemical composition of two dental alloys

Abstract

The aims of this study were: (a) to determine if the presence of probiotic bacteria in an aging medium, that is, artificial saliva in this study, has relevant effects on the surface roughness and the chemical composition of two main alloys used in dentistry (NiTi and stainless steel [SS]) and (b) in the case of NiTi, if these effects are influenced by the coating of the alloy (rhodium and titanium nitride). Atomic force microscopy and Raman spectroscopy were used to study the surface morphology and identify metal oxides formed on the surface of the alloys. Experiments demonstrated that the probiotic bacteria Lactobacillus reuteri can induce processes that alter some features of the surface such as roughness and chemical composition. The effect is dependent on the type of alloy and coating. The bacteria increased roughness in the case of uncoated NiTi more than saliva alone (pH = 4.8). Probiotic bacteria tend to decrease the corrosive influence of saliva on NiTi when the alloy is coated with rhodium or titanium nitride and this effect was also evidenced on SS. Raman spectroscopy confirmed that only SS samples are prone to oxidation processes, predominantly associated with exposure to saliva rather than probiotic bacteria.

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

“…Since adolescent patients are included in this trial, not only the study participant (adolescent) but also the parent and/or legal guardian will be asked about the occurrence of AE. 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 ].…”

“…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 ].…”

“…Contrary, Trolic et al . demonstrated that a probiotic-saliva mixture increased the surface roughness in uncoated NiTi, but decreased roughness of rhodium or titanium nitride coated NiTi and SS archwires [ 94 ]. Pavlic et al .…”

“…concluded that after insertion of orthodontic mini-implants, L. reuteri can reduce corrosion of SS mini-implants, while chlorhexidine should be favoured for titanium implants [ 96 ]. Regarding safety of probiotics during orthodontic treatment with fixed appliances, probiotics appear to decrease corrosion of SS archwires [ 94 , 96 ] and to influence corrosion of NiTi archwires at least to some extent, depending on the surface coating; however, different studies yielded contradictory results [ 94 , 95 ]. NiTi archwires with uncoated surface (BioForce Sentalloy®, Dentsply International GAC, United States) are standard archwires used at the beginning of the orthodontic treatment in the Department of Orthodontics and Orofacial Orthopedics, while stainless steel archwires (3 M™ Unitek™, United States) are standard archwires used in advanced treatment with fixed braces.…”

Temporal dynamics of adhesion of oral bacteria to orthodontic appliances

“…As assumed in the extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, adhesion is the result of long-range forces (Lifshitz -van der Waals forces), electrostatic interaction forces, and short-range Lewis acid-base interactions, which may be attractive or repulsive [10][11][12] . Based on this theory, the characteristics of the material, such as the surface free energy (SFE), hydrophobicity/hydrophilicity, roughness, and topography of the surface, affect bacterial adhesion 1,[13][14][15][16] .…”