Different Parts Of Tooth Research Articles

A novel technique for dental radiographic image segmentation based on neutrosophic logic

Oral diseases are very prevalent worldwide and affect people of all ages. Dentists depend on x-rays to study the characteristics of oral diseases. The segmentation and analysis of dental X-ray images pose various challenges compared to other medical images. This makes dental X-ray imaging more challenging because of poor resolution, which makes the segmentation of different parts of teeth and their abnormalities unreliable. It has been shown that Dental X-ray Image Segmentation (DXIS) is a primary and critical step in obtaining relevant and important details about oral diseases. DXIS plays a crucial role in practical dentistry to help identify various periodontal diseases. The proposed methodology automatically segments the teeth regions and assists in further analysis. It works on both peri-apical and panoramic types of dental radiographic images. Neutrosophic logic is used to select the initial region of interest. The best way to improve the performance and make the system faster is to restrict the computation within the foreground regions. The input dental radiographic image is mapped into the neutrosophic domain using the patch level feature, gradient feature, entropy feature, and local binary pattern. Applying neutrosophic logic helps to localize the initial region of interest. Subsequently, a fuzzy c-means algorithm is applied to segment a more accurate region of interest. The proposed methodology has been evaluated on publicly available data sets, ‘Panoramic Dental X-rays with Segmented Mandibles’ and ‘Digital Dental X-ray Database for Caries Screening,’ with the result that the accuracy of the proposed methodology is as high as 93.20%. This performance level confirms that the proposed segmentation technique highly correlates with the manual system.

Laser-Induced Breakdown Spectroscopy Coupled with PCA Study of Human Tooth

The present study focuses on the laser-induced breakdown spectroscopy (LIBS) studies on different parts of tooth samples. The hardness of different parts of tooth samples belonging to different age groups has been studied using ionic-to-atomic intensity ratio of Ca spectral line. From this ratio, we infer that enamel is the hardest part of teeth. The principal component analysis (PCA) on LIBS data of different parts of teeth gives PC1 (96%) and PC2 (4%), which explains maximum variance present in data set. Therefore, this work demonstrates the suitability of LIBS along with PCA for routine in vitro/in vivo dental practices.

Age-Related Changes in Functional Teeth in the Pacific Walrus (Odobenus rosmarus divergens)

We examined functional teeth (except for upper canine teeth) of Pacific walruses that died or were harvested on the coast of the Chukchi Peninsula in 2005, 2007–2008, and 2010–2011. The dynamics of deposition of annual cement layers was investigated. The rate of cement deposition on the walls of tooth roots decreased significantly with age. The rate of its deposition on the lingual side of the upper teeth was much higher than that on their buccal side, but no such differences were observed on the lower teeth. The same cement layer was deposited unevenly in different parts of teeth (on its different sides and levels) with a general tendency of increasing in the width of the layer from the top to the lower parts of teeth. As a result of local widening of some cement layers with age, the tooth surface became rough, and knolls and rollers appeared there. As the age increased, external changes in teeth occurred: they became larger, more rounded, and heavier. We described a method for the preliminary determination of the relative age of walruses based on the ratio between the width of cement and dentin on the attrition surface of lower teeth (without cutting).

Applicability of tooth derived stem cells in neural regeneration.

Within the nervous system, regeneration is limited, and this is due to the small amount of neural stem cells, the inhibitory origin of the stem cell niche and often to the development of a scar which constitutes a mechanical barrier for the regeneration. Regarding these aspects, many efforts have been done in the research of a cell component that combined with scaffolds and growth factors could be suitable for nervous regeneration in regenerative medicine approaches. Autologous mesenchymal stem cells represent nowadays the ideal candidate for this aim, thank to their multipotency and to their amount inside adult tissues. However, issues in their harvesting, through the use of invasive techniques, and problems involved in their ageing, require the research of new autologous sources. To this purpose, the recent discovery of a stem cells component in teeth, and which derive from neural crest cells, has came to the light the possibility of using dental stem cells in nervous system regeneration. In this work, in order to give guidelines on the use of dental stem cells for neural regeneration, we briefly introduce the concepts of regeneration and regenerative medicine, we then focus the attention on odontogenesis, which involves the formation and the presence of a stem component in different parts of teeth, and finally we describe some experimental approaches which are exploiting dental stem cells for neural studies.

The method of age determination of the Pacific walrus (Odobenus rosmarus divergens) using the layered structure of functional teeth

The functional teeth of Pacific walruses that died or were harvested in the Retkyn Spit, Enmelen village, Kolyuchin Island, Vankarem Cape, Enurmino village, and Chegitun River region in 2005, 2007–2008, and 2010–2011 were examined. The definite structure was investigated in animals of their first year of life. The presence of a milk layer in the tooth dentine can be considered as a mark that all the cement layers have been preserved, and the age determination of an individual is precise. The annual increment of dentine significantly changed with age in different parts of the tooth (buccal, lingual, and central), and the annual growth of dentine decreased every year. The growth rate of the upper jaw teeth was significantly higher, and the duration of their growth was much longer than that in the lower jaw teeth. The wearing of dentine and cement layers was unequal in different parts of tooth. Several recommendations for choosing a tooth for the determination of the walrus’s age and for the estimation of age using the layered tooth structure are given.

Immunohistochemical localization of the NH2-terminal and COOH-terminal fragments of dentin sialoprotein in mouse teeth

Dentin sialoprotein (DSP) is a major non-collagenous protein in dentin. Mutation studies in human, along with gene knockout and transgenic experiments in mice, have confirmed the critical role of DSP for dentin formation. Our previous study reported that DSP is processed into fragments in mouse odontoblast-like cells. In order to gain insights into the function of DSP fragments, we further evaluated the expression pattern of DSP in the mouse odontoblast-like cells using immunohistochemistry and western blot assay with antibodies against the NH(2)-terminal and COOH-terminal regions of DSP. Then, the distribution profiles of the DSP NH(2)-terminal and COOH-terminal fragments and osteopontin (OPN) were investigated in mouse teeth at different ages by immunohistochemistry. In the odontoblast-like cells, multiple low molecular weight DSP fragments were detected, suggesting that part of the DSP protein was processed in the odontoblast-like cells. In mouse first lower molars, immunoreactions for anti-DSP-NH(2) antibody were intense in the predentin matrix but weak in mineralized dentin; in contrast, for anti-DSP-COOH antibody, strong immunoreactions were found in mineralized dentin, in particular dentinal tubules but weak in predentin. Therefore, DSP NH(2)-terminal and COOH-terminal fragments from odontoblasts were secreted to different parts of teeth, suggesting that they may play distinct roles in dentinogenesis. Meanwhile, both DSP antibodies showed weak staining in reactionary dentin (RD), whereas osteopontin (OPN) was clearly positive in RD. Therefore, DSP may be less crucial for RD formation than OPN.

The laterally varying ultrasonic velocity in the dentin of human teeth

There is no quantitative description available that numerically relates any acoustic parameter pattern or the local elastic behaviour to any standardized geometrical positions within human teeth. However, the speed of ultrasound at 20 MHz varies in different parts of teeth. Great differences occur between the values attributed to longitudinal waves that propagate in the three mineralized human hard tissues at identical relative tooth width portions [John, C., 2004. The corono-apically varying ultrasonic velocity in human hard dental tissues. Journal of the Acoustical Society of America 116, 545–556]. The aim of this work was to investigate the distribution of the longitudinal ultrasound velocity (LUV) at distinct relative tooth width portions and at a height level of 8 mm relative to the coronal reference. Individual tooth widths w were accounted for, and a standardized, dimensionless radial distances variable X = | x / w - 0.5 | was utilized to express the radial position of measurements in a unified way. The observed lateral increase in LUV of 21 specimens along X was approximated. A Padé shape function predicts the lower contour of the envelope curve of all the individual LUV distributions. Individual residuals and coefficients are provided for LUV = a + b · ln ( X ) · X · X , where a and b represent individual intercepts and slope factors (e.g. a = 3206 m / s and b = - 4184 m / s ), respectively.

X-ray microprobe synchroton radiation X-ray fluorescence application on human teeth of renal insufficiency patients

This work reports on the measurements of elemental profiles in teeth collected from patients with renal insufficiency. Elemental concentrations of Ti, Mn, Fe, Co, Ni, Cu, Zn, Se, Br, Rb Sr and Pb in different parts of teeth from patients with renal insufficiency are discussed and correlated with the corresponding values for healthy citizens. Both situations, patients with and without dialysis treatment were studied. The purpose of this work is to point out the influence of renal insufficiency together with long dialysis treatment, on teeth elemental content. An X-ray fluorescence set-up with microprobe capabilities, installed at the LURE synchrotron (France) was used for elemental determination. The resolution of the synchrotron microprobe was 100 μm and the energy of the incident photons was 19 keV. Teeth of citizens with renal insufficiency and those submitted since several years to dialysis treatment show a similar concentration with teeth of healthy subjects in what concerns the elemental distribution for Mn, Fe, Cu, Zn and Sr. However, higher levels of Pb were found in pulp region of diseased citizens when compared to values of healthy people. Very low concentrations of Ti, Co, Ni, Se, Br and Rb were found in all the analysed teeth. No difference was found in patients with and without dialysis treatment.