Properties Of Dental Enamel Research Articles

Does the whitening dentifrice containing activated charcoal interfere with the properties of dental enamel? Microhardness, surface roughness and colorimetry analyzes.

The study evaluated the influence of whitening dentifrice containing activated charcoal on microhardness (MH), surface roughness (Ra) and colorimetry of tooth enamel. A total of 60 healthy bovine incisor teeth were used and divided into: G1 (regular non-whitening toothpaste), G2 (conventional whitening toothpaste), G3 (activated charcoal based whitening toothpaste) and G4 (10% carbamide peroxide gel - PC10). Groups G1, G2 and G3 underwent simulated toothbrushing for 14 days, while G4 received bleaching treatment for the same time. The readings of MH, Ra and colorimetry were performed before any intervention (T0 - baseline) and at the end of 14 days of the proposed treatments (T1). After confirming the normality of the data, the results of MH, Ra and colorimetry were subjected to 2-factor ANOVA for repeated measures (α = 5%). For MH, there were no statistical differences in G1, G2 and G3, only in G4. Considering Ra, a significant increase was observed in G2 and G3, with no statistical differences found in the other groups. Regarding colorimetry, the average color difference (ΔE) was greater in the G4 group (11.30 ± 4.31), even compared to the groups submitted to the whitening dentifrices: G2 (5.13 ± 2.75) and G3 (5.86 ± 3.66). It was concluded that the use of a whitening toothpaste containing activated charcoal caused deleterious effects on the enamel Ra, but did not affect the microhardness of the substrate, besides promoting a color change inferior to the regular non-bleaching toothpaste or PC10 gel. Key words:Whitening dentifrice, charcoal, roughness, microhardness.

Mechanical properties of dental enamel after hybridization using electrokinetic flow

Mechanical properties of dental enamel after hybridization using electrokinetic flow

Experimental Studies of Elastic Properties of Dental Enamel and Photopolymer Used for early Caries Treatment

The paper is concerned with the study of the elastic properties of dental enamel and its destruction by a microindentation technique. A series of experiments were performed to find differences in the mechanical properties of healthy and diseased dental enamel. It has been found that the times of dental enamel destruction in healthy and carious areas under a constant force are different. The effect of an infiltrated photopolymer on the hardness and elastic modulus of dental enamel was investigated by microindentation testing. A comparative analysis of the features of healthy, damaged by caries and treated by photopolymer enamel was carried out.

Modification of the mechanical and chemical properties of dental enamel using Er laser radiation with sub-ablative energy density

AbstractLasers can be successfully used for the modification of biological tissues. In dentistry, an increase in strength and the chemical properties of enamel with a laser in order to prevent tooth decay appears to be quite promising. We investigated microhardness and acid resistance of human tooth enamelEnamel of the tooth crown was investigatedThe measured microhardness of intact enamel of human tooth crown wasIn this paper it was found that sub-ablative YLF:Er laser radiation modifies the intact enamel in such a way that the enamel microhardness increases and can exceed the intact enamel microhardness by 20%. Laser-treated enamel can resist abrasive impact during a time equivalent to 3 years of standard dental hygiene. Laser-treated enamel can resist an external aggressive medium containing 37.5% phosphoric acid significantly longer than intact enamel. The observed improvement in the mechanical and chemical properties of the enamel can be explained by a significant reduction in enamel porosity after laser radiation impact.

Nanoindentation mapping of the mechanical properties of human molar tooth enamel

The mechanical behavior of dental enamel has been the subject of many investigations. Initial studies assumed that it was a more or less homogeneous material with uniform mechanical properties. Now it is generally recognized that the mechanical response of enamel depends upon location, chemical composition, and prism orientation. This study used nanoindentation to map out the properties of dental enamel over the axial cross-section of a maxillary second molar (M 2). Local variations in mechanical characteristics were correlated with changes in chemical content and microstructure across the entire depth and span of a sample. Microprobe techniques were used to examine changes in chemical composition and scanning electron microscopy was used to examine the microstructure. The range of hardness ( H) and Young’s modulus ( E) observed over an individual tooth was found to be far greater than previously reported. At the enamel surface H>6 GPa and E>115 GPa, while at the enamel–dentine junction H<3 GPa and E<70 GPa. These variations corresponded to the changes in chemistry, microstructure, and prism alignment but showed the strongest correlations with changes in the average chemistry of enamel. For example, the concentrations of the constituents of hydroxyapatite (P 2O 5 and CaO) were highest at the hard occlusal surface and decreased on moving toward the softer enamel–dentine junction. Na 2O and MgO showed the opposite trend. The mechanical properties of the enamel were also found to differ from the lingual to the buccal side of the molar. At the occlusal surface the enamel was harder and stiffer on the lingual side than on the buccal side. The interior enamel, however, was softer and more compliant on the lingual than on the buccal side, a variation that also correlated with differences in average chemistry and might be related to differences in function.

Enamel Cell Biology Towards a Comprehensive Biochemical Understanding

Enamel cells ultimately determine the properties of dental enamel. Surprisingly little is known about enamel cell functions at the biochemical and molecular levels. Understanding of both normal and abnormal enamel formation should benefit from elucidation of this area. This paper reviews our recent efforts to establish microscale biochemical analyses of rat enamel cells, and the ensuing initial findings about their protein phenotype (i.e., proteome) and calcium-handling mechanisms. A perspective of the current status of enamel cell research, and where it might head, is also given.

Optical Properties of Dental Enamel

IT has been known for many years that dental enamel is birefringent; and its optical properties have been studied intensively by W. J. Schmidt and his pupils1. In a recent paper2, I have shown by X-ray examination that an enamel prism contains a multitude of regularly arranged crystallites of apatite, and have worked out in detail the orientation of these crystallites for human deciduous enamel. It was therefore felt to be of interest to determine whether the optical and X-ray results could be correlated.