Influence of the thickening agent contained in a phosphoric acid etchant on bonding between feldspar porcelain and resin cement with a silane coupling agent

Abstract

Phosphoric acid (PA) etchants are widely used for the bonding pretreatment of teeth; however, their influences on the bonding between glass-ceramics and resin cement have not been clarified yet. This study investigated the effect of a thickening agent on the bonding strength between feldspar porcelain treated with a PA etchant and resin cement with a silane coupling agent. The experiments were performed using two PA etchants: commercial one and prepared one consisting a PA aqueous solution and poly(ethylene glycol) thickening agent. The samples were evaluated by shear bond strength testing, scanning electron microscopy, and Fourier-transform infrared spectroscopy. The obtained results revealed that the thickening agent adhered to the porcelain surface and inhibited cement bonding. Meanwhile, PA remained on the surface due to the presence of the thickening agent and activated the silane coupling agent. Overall, the PA etchant did not improve the bond durability.

Bonding Pretreatment of Aesthetic Dental CAD-CAM Materials through Surface Etching with a Mixed Aqueous Solution of Ammonium Fluoride and Ammonium Hydrogen Sulfate

“…These additives are commonly used to modify etchant consistency to enhance their ease of use and applicability in clinical settings. However, these thickening agents, while improving user-friendliness, can sometimes adversely affect the etching process of glass ceramics as well as the subsequent bond formation between the glass ceramics and the luting agent [ 32 ]. This interaction poses a potential concern regarding the effectiveness and reliability of the etching and bonding processes.…”

“…While HF is recognized for its effective etching of silica-containing materials, its substantial toxicity and related health hazards pose significant concerns, consequently resulting in an ongoing search for safer and less toxic alternatives that can potentially replace HF. Various candidates, including substances like phosphoric acid [ 30 , 31 , 32 ] and fluoride-based products such as Monobond Etch & Prime ® [ 33 , 34 , 35 ], have been explored for their suitability as surface conditioners. However, despite their reduced hazard profiles, these alternatives fall short of HF etching performance and display notably weaker etching capabilities [ 30 , 31 , 32 , 33 , 34 , 35 ].…”

“…Various candidates, including substances like phosphoric acid [ 30 , 31 , 32 ] and fluoride-based products such as Monobond Etch & Prime ® [ 33 , 34 , 35 ], have been explored for their suitability as surface conditioners. However, despite their reduced hazard profiles, these alternatives fall short of HF etching performance and display notably weaker etching capabilities [ 30 , 31 , 32 , 33 , 34 , 35 ]. Currently, there is no alternative etchant that can match the effectiveness of HF for chemically etching CAD-CAM surfaces, thus presenting a significant challenge in dentistry and highlighting the need to balance efficient surface conditioning with the use of safer and less harmful substances.…”

Chemical etching of CAD-CAM glass-ceramic-based materials using fluoride solutions for bonding pretreatment

“…Consequently, there is an ongoing search for safer and less toxic chemical agents that could potentially replace HF. Among the alternatives explored, agents, such as phosphoric acid [22][23][24] and fluoride-containing products (e.g., Monobond Etch&Prime ® ) [25][26][27] , have been investigated for their potential as surface conditioners. Despite their safer profiles, these alternatives have shown limited effectiveness in etching glass-ceramicbased surfaces; their etching abilities are inferior to those of HF [22][23][24][25][26][27] .…”

“…Among the alternatives explored, agents, such as phosphoric acid [22][23][24] and fluoride-containing products (e.g., Monobond Etch&Prime ® ) [25][26][27] , have been investigated for their potential as surface conditioners. Despite their safer profiles, these alternatives have shown limited effectiveness in etching glass-ceramicbased surfaces; their etching abilities are inferior to those of HF [22][23][24][25][26][27] . Because of these limitations, there is currently no alternative etchant that matches the efficacy of HF for the pretreatment of glass-ceramic-based material surfaces.…”