Sphingoid Bases Inhibit Acid-Induced Demineralization of Hydroxyapatite

Abstract

Calcium hydroxyapatite (HAp), the main constituent of dental enamel, is inherently susceptible to the etching and dissolving action of acids, resulting in tooth decay such as dental caries and dental erosion. Since the prevalence of erosive wear is gradually increasing, there is urgent need for agents that protect the enamel against erosive attacks. In the present study we studied in vitro the anti-erosive effects of a number of sphingolipids and sphingoid bases, which form the backbone of sphingolipids. Pretreatment of HAp discs with sphingosine, phytosphingosine (PHS), PHS phosphate and sphinganine significantly protected these against acid-induced demineralization by 80 ± 17%, 78 ± 17%, 78 ± 7% and 81 ± 8%, respectively (p < 0.001). On the other hand, sphingomyelin, acetyl PHS, octanoyl PHS and stearoyl PHS had no anti-erosive effects. Atomic force measurement revealed that HAp discs treated with PHS were almost completely and homogeneously covered by patches of PHS. This suggests that PHS and other sphingoid bases form layers on the surface of HAp, which act as diffusion barriers against H⁺ ions. In principle, these anti-erosive properties make PHS and related sphingosines promising and attractive candidates as ingredients in oral care products. © 2014 S. Karger AG, Basel

Phytosphingosine Prevents the Formation of Young Salivary Biofilms in vitro

“…Solutions of PHS were prepared essentially as described earlier [Valentijn-Benz et al, 2015] to the indicated concentration in 20 mM Tris (Merck, Darmstadt, Germany) (pH = 6.8) supplemented with 0.1% Tween 20 (Tris-Tween; Sigma-Aldrich). Figure 1 shows the molecular structure of PHS.…”

“…The determination of PHS adsorption to glass was performed essentially as described earlier [Valentijn-Benz et al, 2015]. Sterile glass cover slips (12 mm in diameter, 1 mm thick; Thermo Scientific, Braunschweig, Germany) were placed in the wells of 12-well cell culture plates (GreinerBio-One, Frickenhausen, Germany), to which 1.5 mL of a 200 μg/mL PHS solution was added, and incubated on a Heidolph Titramax 101 shaker (150 rpm, 30 min, 37 ° C).…”

Di-Calcium Phosphate and Phytosphingosine as an Innovative Acid-Resistant Treatment to Occlude Dentine Tubules

“…Hence, the high density of positive charges on these aggregates would in effect produce a high avidity for negatively charged phosphate-rich surfaces e.g. HAp [Valentijn-Benz et al, 2015].…”

“…Each main group was then divided in three sub-groups (n = 5 per subgroup) based on the desensitising treatment as follows: PHS: 4-hydroxysphinganine (group A), DCP: brushite (group B), or PHS/ DCP: PHS + brushite (group C). A Tris-Tween/ethanol solution (5 mg/ml) of PHS was prepared as described by Valentijn-Benz et al [2015].…”

“…brushite) have been widely used as a hard tissue substitute due to their bioactivity and biocompatibility [Cama et al 2009]. Moreover, it has been recently reported that the pre-treatment of experimental hydroxyapatite (HAp) discs with sphingoid bases such as sphingosine, phytosphingosine (PHS), PHS phosphate and sphinganine significantly protected HAp against acid demineralisation in vitro [Valentijn-Benz et al, 2015] . Cukkemane et al [2015], using atomic force microscopy, reported that PHS and other sphingoid bases have the ability to form diffusion barriers against H + ions and bacteria.…”