Papers by Keyword: Enamel

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Authors: Faik N. Oktar, Gültekin Göller, Lutfiye Sevgi Özyeğin, E.Z. Erkmen, D. Toykan, H. Demirkıran, H. Haybat
1957
Authors: Keyoung Jin Chun, Ho Jung Li
Abstract: Mandibular first premolars in superlative state were scanned by a Micro-CT. Data were obtained from the scanned 2-D images, and reconstructed into 3-D models for FEA, at which point stress distribution of the inner and outer part of the tooth were shown. It was found that when compared with the teeth data used as a standard by G. V. Black, the aspect of the external morphology of the teeth is comparatively small regardless of gender. Also, differences exist between the Micro-CT data and G. V. Black’s data. This study also presents the internal morphological data that was not shown in G. V. Black’s data. The dentin size is larger than the enamel size in both males and females in the case of the internal morphological data. It is found that the stress was concentrated on the cervical line, and the stress varied around the boundary between dentin and enamel within the teeth. It is also revealed that the stress varied at the boundary surface between dentin and pulp. The results using a Micro-CT and stress analysis may reveal the cause of the abfraction, and bring up a guideline for endodontic treatment.
1139
Authors: Jing Jing Luo, Tian Yun Ning, Ying Cao, Xiao Peng Zhu, Xiao Hua Xu, Xu Yan Tang, Chun Hung Chu, Quan Li Li
Abstract: We here report a novel biomimetic mineralization strategy for enamel remineralization by intergration of calcium phosphate loaded and thermally triggered liposomes and a self-assembly amelogenin-inspired peptide. Firstly, calcium and phosphate loaded temperature sensitive liposomes were synthesized by Interdigitation-fusion method with 1,2-bis(palmitoyl)-sn-glycero-3-phosphor- choline (DPPC) and 1,2-bis(myristoyl)-sn-glycero- 3-phosphocholine (DMPC) at mass ratio of 9:1 . The liposomes were stable at room temperature, but slowly released calcium and phosphate ions if heated to 37 °C. Secondly, a novel polyanion amelogenin-inspired oligropeptide (Gln-Pro-Ala)4-Thr-Lys-Arg-Glu-Glu-Val-Asp ) was synthesized by standard solid-phase. Lastly, the mixture of peptide and liposomes solution was exposed to enamel surface at 37 °C. The results showed oriented enamel-like hydroxylapatite evenly deposited on enamel surface.
1727
Authors: Kun Tian, Min Peng, Ping Wu, Chu Hang Liao, Fa Yin Huang
Abstract: Tooth morphogenesis results from reciprocal interactions between oral epithelium and ectomesenchyme culminating in the formation of mineralized tissues, enamel, and dentin. Based on these basic theory, we design a organic molecules model to induced the crystallization of hydroxyapatite to synthesized tooth-like calcium phosphate/hydroxyapatite with 3D-structure in a controllable way in vitro. We observed that hydroxyapatite nanorods can be controlled followed by in situ phosphorylation process and triggered by conditions of pH and ionic strength. The results showed that he dentinal tubule were blocked by neonatal hydroxyapatite layer and this composite a continuous structure of columns crystal with size of 30-80nm. 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 collagen monolayer may be useful in the modulation of mineral behavior during in situ dental tissue engineering.
633
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.
1347
Authors: Quan Zeng, Yin Hui Zhang, Zhi Hua Xing, Xiao Jun Zhao
Abstract: AFM is used to study tooth surfaces (enamel and cementum) in order to compare the pattern of particle distribution and demineralization process in the two dissimilar tooth hard tissues. Our approach is focusing mainly on the qualitative observations of tooth surface morphology and quantitatively measuring the early stages of mineral loss. The native enamel presented globular particles tightly packed. After polishing the aprismatic layer, the particles observed were relatively larger and more organized than ones in the outmost enamel surface. The cementum had small grains arranged in some degree of ordered packing with varying crystallite orientations. After different time treatment with citric acid solution, all the sample surfaces became more irregular and had the deeper grooves. The maximum mineral loss was greatest for the cementum sample and lowest for the native enamel. The demineralization difference between the enamel and cementum shows the structure and component play important roles in the morphological changes of demineralization. These demonstrate that the microstructure and demineralized difference between enamel and cementum obtained with AFM are complementary to the usual SEM images and TEM data. AFM is suitable for measuring early stages of tooth surface demineralization.
733
Authors: Attapol Choeysuppaket, Artorn Pokaipisit, Pichet Limsuwan
Abstract: The aim of the present study was to investigate the organic and inorganic compositions of enamel and dentine after Er:YAG laser irradiation using Fourier-transform Raman spectroscopy (FT-Raman). The enamel and dentine of extracted human teeth were irradiated by Er:YAG laser at an energy density of 29.7 J/cm2. The organic and inorganic components were evaluated from Raman spectra of untreated and laser-treated of extracted human teeth. The results showed that the Raman intensity ratio of the carbonate peak (1067 cm-1) to the phosphate peak (957 cm-1) and the organic peak (2940 cm-1) to the phosphate peak of enamel and dentine decreased after laser irradiation. Therefore, laser treatment can reduce the organic and inorganic components of human enamel and dentine.
529
Authors: Xiu Lan Chen, Huang Qin Chen
Abstract: The purpose of this study was to investigate the effect of liquid polishing system (BisCover) on color stability of the bleached enamel upon exposure to a staining agent-red wine. Forty specimens were prepared. They were divided into 2 groups and different procedures, including only bleaching with Opalescence PF (PF) or Opalescence regular (R) gels, and application of BisCover after blaeching (PF-B, R-B) were used. Unbleached specimens were served as control groups (control-1 and control-2). The specimens were stored for 48 h in red wine. The color of all specimens was measured before and after exposure with a spectrophotometer, and total color change (ΔE*) were calculated. The data were analyzed with a one-way ANOVA and the means were compared by Tukeys post hoc analysis (α=0.05). PF-B and R-B groups demonstrated significantly less color change than PF and R groups. the control-1 and control-2 groups had the least color change. No significant difference were observed between PF and R group. BisCover improved the color stability of bleached enamel in red wine.
141
Authors: Loredana Colceriu, Sanda Cimpean, Codruta Nicola, Sorina Sava, Marcela Trif, Tinca Buruiana, Marioara Moldovan, Laura Silaghi-Dumitrescu, Aurora Antoniac, Ana-Iulia Blajan, Cristina Prejmerean
Abstract: The present study was conducted with the aim of evaluating and comparing the microleakage at the dentin and enamel/composite interfaces of two adhesive systems. The adhesives are: a new-developed experimental adhesive systems and OptiBond FL (Kerr Corp.) The new adhesive system was prepared for the composite material as three steps adhesive (etchant, primer and bonding). The bonding resin contains the base monomer that was present in the corresponding composite material, HEMA and TEGDMA as diluents. Twenty box-type Class V standardized cavities were prepared on the facial and oral surfaces of each tooth, with coronal margins in enamel and apical margins in cementum (dentin). The preparations were restored with two restorative materials a new experimental microfilled resin composites based on Bis-GMA analogue and hybrid resin composite Herculite XRV Ultra (Kerr Corp.). The teeth were thermocycled and immersed in 2% methyl blue solution for 24 hours. The specimens were sectioned buccolingually into 3 slices and the resulted sections were examined using a stereomicroscope under 40x magnification. The extent of dye penetration was measured in a quantitative manner. This measurement was converted into percentage using the formula described by Sano et al. I=p/Lx100. These percentage values were submitted to variance analyses (ANOVA) and t test at a p<0.05 level of significance. Scanning electron microscopy was used in order to see the interface between tooth and composite restoration. Significantly less microleakage was associated with the use of OptiBond FL adhesive system at the enamel surface. Between the enamel and the dentin margins no significantly statistical differences were found just for the experimental adhesive system. This adhesive containing water and ethanol as solvent performed significantly better at the dentin margins.
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