Synthesis of plate-like β-tricalcium phosphate nanoparticles and their efficiency in remineralization of incipient enamel caries

Abstract

The purpose of this study was to synthesize nano-sized β-tricalcium phosphate (nano-TCP) particles and determine its concentration-dependent properties on incipient enamel caries lesions. Nano-TCP was synthesized as a wet chemical through a method using low concentration of precursors and low addition rate of calcium nitrate tetrahydrate as a second phase. Morphology and phase composition of the particles were analyzed by SEM, XRD, and EDXA techniques. Incipient enamel lesions were created in human premolars with an acidic buffer. The teeth were then incubated in aqueous dispersions of nano-TCP as remineralization solutions. Sodium fluoride solution and deionized water were used as positive and negative control groups, respectively. The quality and thickness of the remineralized layer on enamel were investigated using SEM. The data were statistically analyzed by analysis of variance (ANOVA) and post hoc Tukey's test. The synthesized nano-TCP mostly consisted of porous platelet-like crystals of 50-100 nm thickness and pore diameters of 100-300 nm. SEM observation showed that a homogenous layer was formed on the surface of the enamels remineralized in nano-TCP solutions. The thickness of the mineralized layer was dependent on the incubation time and nano-TCP concentration.

Keywords: Incipient enamel caries lesions; Nanoparticle; Platelet morphology; Remineralization; β-Tricalcium phosphate.

Fig. 1

SEM photomicrographs of pre-calcined TCP (a), nano-TCP-1 (b) and nano-TCP-2 (c)

Fig. 2

X-ray diffraction pattern of beta-TCP standard card (a) (JCPDS No. 09-0169), nano-TCP-1 (b) and nano-TCP-2 (c)

Fig. 3

SEM photomicrographs of the natural tooth (A1: surface, A2: cross-section), and caries induced tooth (B1: surface, B2: cross-section)

Fig. 4

SEM photomicrographs of the teeth treated with NaF 0.05 wt% solution (Group I, positive control). The a–c codes stand for micrographs obtained from the tooth surface (× 1000 mag.), tooth surface (× 5000 mag.) and tooth cross-section (× 1000 magnification). The digits (4, 8, and 16) after alphabets denote the incubation time in days

Fig. 5

SEM photomicrographs of the teeth treated with nano-TCP 0 wt% solution (Group II, negative control). The a–c codes stand for micrographs obtained from the tooth surface (× 1000 mag.), tooth surface (× 5000 mag.), and tooth cross-section (× 1000 mag.). The digits (4, 8, and 16) after alphabets denote the incubation time in days

Fig. 6

SEM photomicrographs of the teeth treated with nano-TCP 1 wt% solution (Group III). The a–c codes stand for micrographs obtained from the tooth surface (× 1000 mag.), tooth surface (× 5000 mag.), and tooth cross-section (× 1000 mag.). The digits (4, 8, and 16) after alphabets denote the incubation time in days

Fig. 7

SEM photomicrographs of the teeth treated with nano-TCP 3 wt% (Group IV). The a–c codes stand for micrographs obtained from the tooth surface (× 1000 mag.), tooth surface (× 5000 mag.), and tooth cross-section (× 1000 mag.). The digits (4, 8, and 16) after alphabets denote the incubation time in days

Fig. 8

SEM photomicrographs of the teeth treated with nano-TCP 5 wt% (Group V). The a–c codes stand for micrographs obtained from the tooth surface (× 1000 mag.), tooth surface (× 5000 mag.), and tooth cross-section (× 1000 mag.). The digits (4, 8, and 16) after alphabets denote the incubation time in days