Enamel roughness and depth profile after phosphoric acid etching of healthy and fluorotic enamel

Abstract

Background: Dental fluorosis requires aesthetic treatment to improve appearance and etching of enamel surfaces with phosphoric acid is a key step for adhesive restorations. The aim of this study was to evaluate surface roughness and a depth profile in healthy and fluorotic enamel before and after phosphoric acid etching at 15, 30 and 60 seconds. Methods: One hundred and sixty enamel samples from third molars with no fluorosis to severe fluorosis were evaluated by atomic force microscopy. Results: Healthy enamel showed a statistically significant difference (p < 0.05) between mean surface roughness at 15 seconds (180.3 nm), 30 seconds (260.9 nm) and 60 seconds (346.5 nm); depth profiles revealed a significant difference for the 60 second treatment (4240.2 nm). For mild fluorosis, there was a statistically significant difference (p < 0.05) between mean surface roughness for 30 second (307.8 nm) and 60 second (346.6 nm) treatments; differences in depth profiles were statistically significant at 15 seconds (2546.7 nm), 30 seconds (3884.2 nm) and 60 seconds (3612.1 nm). For moderate fluorosis, a statistically significant difference (p < 0.05) was observed for surface roughness for 30 second (324.5 nm) and 60 second (396.6 nm) treatments. Conclusions: Surface roughness and depth profile analyses revealed that the best etching results were obtained at 15 seconds for the no fluorosis and mild fluorosis groups, and at 30 seconds for the moderate fluorosis group. Increasing the etching time for severe fluorosis decreased surface roughness and the depth profile, which suggests less micromechanical enamel retention for adhesive bonding applications.

Shear bond strength evaluation of bonded molar tubes on fluorotic molars

“…21 With respect to the micrographs taken from molars with SEF, after etching for 15 seconds, the surface appeared almost intact; when performing etching for 150 seconds, a rough surface was observed, but the SBS was less than that obtained with etching for 15 seconds. This was explained by Torres-Gallegos et al, 22 who used AFM to evaluate the surface roughness and depth profile in healthy and fluorosed enamel. They concluded that increasing the etching time in SEF cases can decrease the surface roughness and depth profile, which may produce a less effective micromechanical enamel surface for effective adhesive bonding.…”

Comparison of resin-based and glass ionomer sealants with regard to fluoride-release and anti-demineralization efficacy on adjacent unsealed enamel

“…In this study design, fluoride-release was monitored in the presence of an enamel substrate that underwent pre-treatment with acid etching prior to sealant application. Etching sound enamel with 37% phosphoric acid for 15 s removes approximately 3 µm of enamel tissue, exposes the enamel prisms, and affects demineralization up to a depth of 50 µm 32,33) . In TF, 40% phosphoric acid was used and, therefore, the enamel surface was probably demineralized more or less to a similar extent.…”

Influência da marca do condicionador ácido na resistência de união da resina composta à dentina

“…Nesta abordagem, busca-se a criação de espaços no substrato dental, seguida pela penetração e pela polimerização da resina adesiva. O condicionamento ácido do esmalte causa a dissolução da periferia ou do centro do prisma de esmalte, criando porosidades e aumentando a energia de superfície desse substrato 3,4 . Essas alterações possibilitam a penetração do adesivo nas porosidades do esmalte, formando a zona de interdifusão, responsável pela união 1,2,5 .…”