Papers by Keyword: Remineralization

Abstract: Calcium phosphates are excellent biomaterial for hard tissue regeneration and replacement. Recently, nanohydroxylapatite (HAp) has been intensively studied as remineralization agent for tooth enamel protection and remineralization. In this research, we developed model toothpaste composition, determined viscosity and investigated weather different processed – spray-dried (spCDHAp), lyophilized (lyoCDHAp), wet precipitated (paste-like consistence, pCDHAp) – calcium deficient hydroxyapatite (CDHAp) affect bovine tooth enamel remineralization. Model toothpastes components were CDHAp, 2-hydroxyethylcelluloce, glycerol and water. Viscosity varied from 2.5 to 40 Pa∙s. Model toothpastes with 20 wt% CDHAp showed thixotropic behaviour, thereby we examined them as potential tooth remineralization pastes. After in vitro remineralization enamel surface changes were detected, the texture of demineralized surface and bundles of HAp crystals were not observed. It was suggested, that new calcium phosphate layer was formed on the enamel. In conclusion, CDHAp is very promising material for enamel regeneration, but different pretreatment of CDHAp (resulting as different morphology of agglomerates) did not give distinctive remineralization results.

Abstract: In order to repair the etched human dental enamel, 45S5 bioactive glass with different particle size was used to remineralization enamel in vitro. 45S5 bioactive glass powder was sieved, and divided into the three groups. Freshly sound human second molar teeth from patients were extracted and specimens of dentine-enamel junction were prepared under water-cooled diamond saw, then the enamel surface was polished and finally rinsed. The enamel samples were soaked in simulated oral fluid (SOF) for 5 days. Particle size distribution, topological images and mechanical properties such as hardness and reduced modulus of enamel surface were evaluated by the laser particle size analyzer, atomic force microscope (AFM) and nanoindentation technology. The results indicated that the adhered particle size onto the enamel surface was concentrated on the 1-10 μm. With the decreasing particle size, adhesive capacity onto the enamel surface increased, but the mechanical properties decreased gradually after soaking in SOF for 5 days. In a short period time, Group 2 particles are suitable of repair the etched enamel, and further improve its mechanical properties. This study suggests that proper size 45S5 bioactive glass may be used to repair the acid etched teeth as a toothpaste additive.

Abstract: The formation of organized nanocrystals that resemble tooth-like hydroxyapatite is crucial for successful enamel remineralization. Based on the principles of biomineralization , spindle - shaped hydroxyapatites (HA) were synthesized through biomimetic method with chitosan as template under a controllable way in vitro. We observed that hydroxyapatite nanorods can be controlled followed by in situ crosslinking process and triggered by conditions of pH and ionic strength. The dentinal tubule were blocked by neonatal hydroxyapatite layer and this composite a continuous structure of columns crystal with size of 10-40nm. At the same time, XRD showed that the precipitation was calcium fluoride phosphate and Ca:P was 1.6. Furthermore, there were column crystal with parallel direction inside, as same as the crystal array in the top of enamel rod. The results suggest that chitosan monolayer may be useful in the modulation of mineral behavior during in situ dental tissue engineering.

Abstract: Tricalcium silicate (Ca₃SiO₅) bioceramics have good bioactivity and compatibility. In simulated oral fluid they can induce teeth mineralization to repair the acid etched dental enamel. But teeth mineralization effect was relied on particles adhesive ability onto the enamel surface, so a new and simple method was established to evaluate the adherence quantitatively by optical micrograph analyzer and particle counter based on light blocking theory, and further verified Ca₃SiO₅ particle size affected mineralization effect in stimulated oral fluid (SOF) by nanoindentaion depth. The results indicated that particle size affected the adhesive capability and mineralization ability, in the size of 1-10μm is optimal selection as a toothpaste agent against early caries.

Abstract: The aim of this study is to describe the remineralization effect of the nano-HA on artificial caries. The artificial dental caries are made by using sour solution, and constructing an artificial mouth' plaque culture system in vitro respectively. The scanning electron microscope (SEM) and the optical microscope are used to observe the surface of enamel specimens. The effect of remineralization is assessed with the polarized light microscopy (PLM) and the confocal laser scanning microscope (CLSM) by measuring three lesion parameters (area, total and average fluorescence). The SEM analysis shows that the cavities and defects of enamel surface are decreased and many mineral salts are sedimentated, which indicate that the nano-HA could promote remineralization for the demineralized enamel. The inhibitory effect of the spherical nano-HA on dental caries is detected in the artificial mouth test. The CLSM shows that demineralization of enamel is reduced by adding the spherical nano-HA in artificial mouth. The results show that the spherical nano HA have a remineralization effect on the artificial dental caries dramatically, and can prevent and decrease caries.

Abstract: This study aimed to evaluate the anticariogenic and remineralization effects of the glass ionomer dental luting cement containing nano-β-TCP in vitro. The β-Tricalcium Phosphate (β-TCP) are the components of dental enamel and bone mineral as biological apatites. In addition, β-TCP contains a significant amount of calcium and phosphate, which can promote remineralization of enamel subsurface lesions in animal and human. RelyXTM glass ionomer cement(3M/ESPE, USA) was used as dental luting cement. Film thickness, setting time, and compressive strength was measured for each group of pure glass GIC, 15% nano-β-TCP GIC. Human molars were prepared in box-shaped cavities that were filled with the GIC with and without the 15% nano-β-TCP were placed in 25ml of pH 5.0 acid buffer for 4 days at 37°C. After 4 days, longitudinal sections (1007m) were obtained through the center of each restoration. The sections were analyzed using a scanning electronic microscope (SEM) and confocal laser scanning microscopy (CLSM) to identify the change in the enamel surface. A significant difference in the CLSM images between pure GIC and nano-β-TCP-GIC. CLSM allows the demineralized surface layers of sound enamel to be visualized down to approximately 100 μm. The pure GIC specimens had a relatively thick fluorescent layer. On the other hand, the fluorescent layer of the nano-β-TCP-GIC specimens were thinner. The SEM images of micro surfaces demonstrate that nano-β-TCP-GIC is less rough than pure GIC. Therefore, the addition of nano-β-TCP enhanced protection against acid demineralization and promoted remineralization of enamel surface.

Abstract: The objective of this study was to investigate the inhibitory effect of the synthetic nanohydroxyapatite (HA) on dental caries. The nano-HA was synthesized by using the depositing reaction of Ca (H2PO4)2. The artificial dental caries was made by using sour solution and inoculating Streptococcus mutans (S.mutans) to the Sprague-Dawley (SD) rat’s mouth respectively. After mineralization of solution of nano-HA for 10 days, the hardness of enamel was measured. The inhibitory effect of the synthetic nano-HA on dental caries was detected by gargling way to rinse the rat tooth with the solution of nano-HA in the animal test. Transmission electron microscopy (TEM) revealed that the dried HA particles were needle-like with ф5-20nm×60nm and the sintered HA particles were spherical with less than 100nm. The remineralized test indicated that the solution of nano-HA with different shapes enhanced the hardness of artificial caries and improved the remineralization of artificial caries. The animal test showed that the dried nano-HA had the inhibitory effect on dental caries. The good absorptive effect of the nano-HA on both the saliva protein and the glucans leads to the development of interventions that could reduce or modify bacterial colonization of tooth surfaces.

Abstract: The use of specific remineralizing agents in toothpastes may help to prevent caries and treat dentinal sensitivity. In this study, applied nanotechnologies were used to develop a filler for toothpastes with remineralizing properties. Carbonate hydroxyapatite nanocrystals, with size, morphology, chemical composition and crystallinity comparable with that of dentine, were synthesized in mild condition. The remineralizing effect was studied with a scanning electron microscopy putting materials onto the slices of dentine previously demineralized with ortophosphoric acid. The application of the materials showed the progressive closure of the tubular openings of the dentine with plugs within 10 minutes and a regeneration of a surface mineral layer within 6 hours. This rates of remineralization seems to be compatible with the development of toothpastes with remineralizing effect.

Abstract: The aim of this study was to evaluate the remineralizing potential of demineralized human dentin treated with Y/HA nanoparticles (doping Y with 5mol %) and HA nanoparticles suspension and whether dentin could be remineralized by HA. Human crown dentin was demineralized with EDTA for 4 hours, and then subjected to remineralization condition. The ability of these matrices to remineralize was determined by SEM, AFM and calcium levels in the remineralized tissue were measured by atomic energy spectrum analysis. The results showed that Y/HA and HA nanoparticles remineralized the demineralized dentin surface; these demineralized matrices treated with Y/HA nanoparticles remineralized to a greater extent than those treated HA nanoparticles. The differences in both the quality and quantity, as defined by Yttrium iones leading to changes in characterization of the apatite crystals might be important in effecting the ability of this tissue to remineralize. This work suggested that apatite nanoparticles caused remineralization of dentin and the yttrium ions substituted in the apatite structure might enhance their remineralization potential.

Abstract: A previous study reported that many supplements have been added to NaF mouthrinses to improve the remineralization potential. Nano-hydroxyapatite (nano-HA) might also be suitable to this purpose because these nano-size particles can penetrate the enamel pores. Moreover, hydroxyapatite is similar to the inorganic component of teeth and is both bioactive and biocompatible. The aim of this study was to evaluate the combined effects of a nano-HA and fluoride mouthrinse on an early caries lesion in human enamel using an in vitro cycle remineralization and treatment model. Forty-eight human enamel specimens, which had a Vickers Hardness Number (VHN) of 25~45 were artificially demineralized for 48h. There were 8 treatment groups (0%, 1%, 5%, 10% nano-HA in distilled water and the same concentrations of nano-HA in a 0.05% NaF solution). The specimens were incubated in an in vitro remineralization model. After immersing the specimens into the treatment and remineralization solution for 12 hours each, the VHN of each specimen was evaluated for total 24 hours. This step was repeated once again for total 48 hours. The enamel surfaces of all specimens were examined by Confocal Laser Scanning Microscopy (CLSM) and SEM. The statistical significance of the data was identified by one-way ANOVA followed by a Duncan’s studentized range test. A p value < 0.05 was considered significant. The results showed that the degree of remineralization, as revealed by the VHN values, was higher in the NaF groups than in the distilled water groups. The VHNs of the remineralized enamel specimens for 48 hours were higher than after the 24 hours treatment. In addition, the level of remineralization increased with increasing concentration of nano-HA and was more pronounced in the NaF groups than the distilled water groups (p<0.05). The CLSM and SEM images nano-sized particles attached to the enamel in the nano-HA treated groups. Nano-HA might play a synergistic role in remineralization with a fluoride mouthrinse. However, more study will be needed to determine the optimal condition of nano-HA and NaF mouthrinse for human use. In conclusion, nano-HA in a 0.05% NaF mouthrinse can help remineralize an early caries lesion.