Papers by Keyword: Remineralization

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Authors: Vita Zalite, Janis Locs
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.
Authors: M.Y. Kim, H.K. Kwon, Choong Ho Choi, B.I. Kim
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.
Authors: Zhen Tan, Hong Kun Wu, An Chun Mo, Zhi Qing Chen, Yu Bao Li
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.
Authors: S. H. Jeong, Suck Jin Hong, Choong Ho Choi, B.I. Kim
Abstract: The process of dental caries is dynamic and continuous, with periods of de- and remineralization of the tooth structure occurring over time. When the remineralization potential is superior to demineralization, the caries process can be stopped and early caries lesions can recover. Moreover, the remineralization potential will be increased if active components are added to a dentifrice. Therefore, the aim of this study was to re-evaluate the remineralizaton potential of a dentifrice containing nano-sized carbonated apatite using pH cycling, which simulates the oral environment. Artificial incipient caries was induced on bovine tooth specimens, which were treated with 4 dentifrices containing several concentrations of nano carbonated apatites with pH cycling. The remineralization effect was evaluated at each step by measuring the Vickers Hardness Number, and obtaining SEM and CLSM images of the enamel surface. The micro hardness of the enamel surface increased after the pH cycling treatment of the dentifrices. The dentifrice containing 5% n-CAPs showed the highest level of remineralization followed by 0%, 15% and 30%. One-way ANOVA indicated a significant difference in remineralization between the dentifrice containing 5% and 30% n-CAPs. SEM and CLSM also demonstrated observable differences in each step. From this study, the fluoride dentifrice containing 5% n-CAPs was effective in remineralizing an artificial incipient caries lesion. In conclusion, the dentifrice containing 5% nano carbonated apatites and 25% silica was the most effective in remineralizing early caries lesion.
Authors: Kun Tian, Min Peng, Wei Fei, Chu Hang Liao, Xiao Hua Ren
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.
Authors: Kui Long Lu, Xiang Cai Meng, Jiu Xing Zhang, Xing Yi Li, Mei Ling Zhou
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.
Authors: Zhi Hong Dong, Chang Chun Zhou
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.
Authors: Zhi Hong Dong
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.
Authors: Kui Long Lv, Jiu Xing Zhang, Xiang Cai Meng, Xing Yi Li
Abstract: The aim of this study is to describe the remineralization effect of the nano-HA toothpaste on artificial caries. The artificial dental caries is made using sour solution. The demineralized teeth specimen is put into five kinds of toothpaste solution respectively for 5 days and 10 days, which are: solution of containing needle like nano-HA, solution of containing spherical nano-HA, solution of general HA, fluorine sodium solution and physiological saline. The hardness of specimen is measured and the surface morphology is characterized by SEM. The remineralized test indicates that the nano-HA toothpaste can enhance the hardness of artificial caries and improve the remineralization of artificial caries. 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.
Authors: S. H. Jeong, S.O. Jang, Kyoung Nam Kim, H.K. Kwon, Yong Duk Park, B.I. Kim
Abstract: Hydroxyapatite is the main component of enamel that gives the tooth a bright white appearance and eliminates the diffused reflection of light by filling up the fine pores of the tooth surface. Accordingly, remineralization of the teeth can be expected to some extent if hydroxyapatite is used to treat an incipient caries lesion (early white spot lesion). In addition, the remineralization effect will be increased if the particle size of hydroxyapatite can be reduced to less than that of the micron-size in existing toothpaste preparations. The aim of this in vitro study was to evaluate the effect of nano-hydroxyapatite toothpaste, which was produced by nano-technology, on the remineralization of human enamel. A tooth specimen, on which artificial incipient caries had been induced, was immersed into two toothpaste slurries for remineralization. One contains nano-sized hydroxyapatite and fluoride, and the other contains nano-sized hydroxyapatite excluding fluoride. In order to evaluate the remineralization effect, the Vickers Hardness Number & SEM image of the enamel surface was evaluated at each step. There were significant differences in VHN values between those obtained before and after the remineralization steps. The results showed that the remineralization effect increased with increasing immersing time (P<0.05). However, there were no significant differences in VHN values between the two groups (P>0.05). SEM also demonstrated differences the in micro surface at each step. In conclusion, a toothpaste containing nano-sized hydroxyapatite has the potential to remineralize an incipient caries lesion. In addition, the addition of fluoride had no synergistic effect on remineralization.
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