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Journal of Cancer Research and... 2020The objective of this study is to evaluate the effects of radiotherapy doses on mineral density and percentage mineral volume of human permanent tooth enamel.
OBJECTIVE
The objective of this study is to evaluate the effects of radiotherapy doses on mineral density and percentage mineral volume of human permanent tooth enamel.
MATERIALS AND METHODS
Synchrotron radiation Xray microcomputed tomography (SRμCT) and microhardness testing were carried out on 8 and 20 tooth samples, respectively. Enamel mineral density was derived from SRμCT technique using ImageJ software. Microhardness samples were subjected to Vickers indentations followed by calculation of microhardness and percentage mineral volume values using respective mathematical measures. Data were analyzed using paired t-test at a significance level of 5%. Qualitative analysis of the enamel microstructure was done with two-dimensional projection images and scanned electron micrographs using μCT and field emission scanning electron microscopy, respectively.
RESULTS
Vickers microhardness and SRμCT techniques showed a decrease in microhardness and an increase in mineral density, respectively, in postirradiated samples. These changes were related to mineral density variation and alteration of hydroxyapatite crystal lattice in enamel surface. Enamel microstructure showed key features such as microporosities and loss of smooth homogeneous surface. These indicate tribological loss and delamination of enamel which might lead to radiation caries.
CONCLUSIONS
Tooth surface loss might be a major contributing factor for radiation caries in head-and-neck cancer patients prescribed to radiotherapy. Such direct effects of radiotherapy cause enamel abrasion, delamination, and damage to the dentinoenamel junction. Suitable measures should, therefore, be worked out to protect nontarget oral tissues such as teeth while delivering effective dosages to target regions.
Topics: Dental Enamel; Hardness; Head and Neck Neoplasms; Humans; In Vitro Techniques; Microscopy, Electron, Scanning; Radiation Injuries; Surface Properties; Tooth Demineralization; X-Ray Microtomography
PubMed: 32719276
DOI: 10.4103/jcrt.JCRT_8_19 -
Journal of Visualized Experiments : JoVE Aug 2018Stable carbon and oxygen isotope analysis of human and animal tooth enamel carbonate has been applied in paleodietary, paleoecological, and paleoenvironmental research...
Stable carbon and oxygen isotope analysis of human and animal tooth enamel carbonate has been applied in paleodietary, paleoecological, and paleoenvironmental research from recent historical periods back to over 10 million years ago. Bulk approaches provide a representative sample for the period of enamel mineralization, while sequential samples within a tooth can track dietary and environmental changes during this period. While these methodologies have been widely applied and described in archaeology, ecology, and paleontology, there have been no explicit guidelines to aid in the selection of necessary lab equipment and to thoroughly describe detailed laboratory sampling and protocols. In this article, we document textually and visually, the entire process from sampling through pretreatment and diagenetic screening to make the methodology more widely available to researchers considering its application in a variety of laboratory settings.
Topics: Animals; Carbon; Carbon Isotopes; Dental Enamel; Humans; Oxygen Isotopes
PubMed: 30176003
DOI: 10.3791/58002 -
BMC Oral Health Dec 2023To measure adequate enamel thickness of maxillary incisors in planning enamel reduction for a porcelain laminate veneer restoration in relation to chronological age and...
BACKGROUND
To measure adequate enamel thickness of maxillary incisors in planning enamel reduction for a porcelain laminate veneer restoration in relation to chronological age and sex by using cone beam computed tomography (CBCT) in an Iraqi subpopulation.
METHODS
From 81 CBCT images, 324 maxillary incisors were examined. Enamel thickness was measured at both mesial and distal regions of the tooth in three different levels: cervical, middle, and incisal (occlusal) 1/3 at a sagittal section. Measurements were made for the following tooth areas using CBCT: facial enamel thickness at 1, 3, and 5 mm from the cementoenamel junction (CEJ), palatal enamel thickness at 5 mm from the CEJ (5 mm P), facial and palatal enamel thickness at the incisal edge (IFP), mid incisal enamel thickness (IET), and the incisal edge enamel-pulp distance (IEPD). Relationships of enamel thickness with age and sex were evaluated using Independent t-test, Mann-Whitney U-test and the Pearson correlation coefficient, a simple linear regression analysis used for statistical analysis.
RESULTS
Significant differences (P < 0.05) were found in terms of an inverse association between enamel thickness and chronological age at all measurements above the CEJ and the regression model for the mid-incisal enamel thickness was (R2 of 0.4). In contrast, there was an increase in IFP, palatal, and IPED enamel thickness with age. Also, significant differences were found in enamel thickness between males and females, the enamel being thicker in females in relation to facial enamel thickness, enamel palatal thickness above CEJ and IET, while for IEPD, the enamel thickness was greater in males compared to females.
CONCLUSION
The measurements for enamel thickness outcome variables in relation to chronological age revealed significant differences for each measured distance and there were statistically significant differences in enamel thickness between males and females at all measurements except at IFP. These results demonstrate that CBCT can be used for noninvasive, accurate measurements of enamel thickness in both sex.
Topics: Male; Female; Humans; Incisor; Maxilla; Dental Enamel; Tooth Cervix; Dental Materials; Cone-Beam Computed Tomography
PubMed: 38057794
DOI: 10.1186/s12903-023-03639-y -
Scientific Reports Jan 2021Strontium isotopic analysis of sequentially formed tissues, such as tooth enamel, is commonly used to study provenance and mobility of humans and animals. However, the...
Strontium isotopic analysis of sequentially formed tissues, such as tooth enamel, is commonly used to study provenance and mobility of humans and animals. However, the potential of Sr/Sr in tooth enamel to track high-frequency movements has not yet been established, in part due to the lack of data on modern animals of known movement and predictive model of isotope variation across the landscape. To tackle this issue, we measured the Sr/Sr in plant samples taken from a 2000 km area in the Altai Mountains (Mongolia), and the Sr/Sr in tooth enamel of domestic caprines whose mobility was monitored using GPS tracking. We show that high-resolution, sequential profiles of strontium isotope composition of tooth enamel reliably reflect the high-frequency mobility of domestic livestock and that short-term residency of about 45 days can be resolved. This offers new perspectives in various disciplines, including forensics, ecology, palaeoanthropology, and bioarchaeology.
Topics: Animal Migration; Animals; Biological Availability; Dental Enamel; Geographic Information Systems; Geography; Goats; Laser Therapy; Mongolia; Strontium Isotopes; Time Factors
PubMed: 33500495
DOI: 10.1038/s41598-021-81923-z -
Australian Dental Journal Sep 2017Several studies have investigated the effect of bleaching on dental tissues. The evaluation of the effect of home bleaching with 10% carbamide peroxide is important for... (Meta-Analysis)
Meta-Analysis Review
Several studies have investigated the effect of bleaching on dental tissues. The evaluation of the effect of home bleaching with 10% carbamide peroxide is important for assessing alterations in enamel microhardness that may affect dental health in terms of resistance to masticatory forces. This meta-analysis was performed in order to determine scientific evidence regarding the effects of home vital bleaching with 10% carbamide peroxide gel on the microhardness of human dental enamel. A systematic electronic literature search was conducted in the PubMed and Web of Science databases using search terms. Two independent researchers evaluated the information and methodological quality of the studies. Inclusion and exclusion criteria were established for article selection; further, only studies published in English were selected. Thirteen studies that met all of the inclusion and exclusion criteria were selected and underwent statistical analysis. The results of this meta-analysis showed no significant changes in enamel microhardness when using the 10% carbamide peroxide bleaching gel over periods of 7, 14 and 21 days.
Topics: Carbamide Peroxide; Dental Enamel; Dental Enamel Solubility; Dental Stress Analysis; Drug Combinations; Hardness; Humans; Peroxides; Tooth Bleaching; Tooth Bleaching Agents; Urea
PubMed: 27997982
DOI: 10.1111/adj.12494 -
The Angle Orthodontist Sep 2021To quantify differences in the etch quality of enamel within and between human teeth, which has not previously been attempted. (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVES
To quantify differences in the etch quality of enamel within and between human teeth, which has not previously been attempted.
MATERIALS AND METHODS
The buccal right and left halves of 27 extracted human teeth were randomly allocated to scanning electron microscopy (SEM) or micro-computed tomography (μCT) for evaluation. The buccal surfaces were pumiced, etched with 37% phosphoric acid gel etchant for 15 seconds, rinsed, and air dried. Each tooth was divided into three regions (incisal, middle, and cervical) and viewed after etching at 1200× magnification with SEM. The μCT scans were taken before and after etching to calculate apparent and material mineral densities.
RESULTS
SEM showed greater aprismatic enamel and poorer etch quality (ie, significantly less percentage enamel) for the posterior than anterior teeth and for the cervical region than for the incisal and middle regions of all teeth. Although there were no density differences prior to etching, μCT demonstrated that etching increased material density significantly more for the anterior than posterior teeth. Prior to etching, the enamel in the cervical regions was significantly less dense than the enamel in the middle or incisal regions. Etching significantly increased the material density of all three regions, which decreased initial regional differences. After etching, the apparent density of the cervical region remained significantly lower than the densities of the other two regions.
CONCLUSIONS
Based on SEM and μCT, there is greater aprismatic enamel and inferior etch quality in the cervical regions of all tooth types and is clinically significant in explaining the failure of sealant retention and the propensity for white spot lesions.
Topics: Acid Etching, Dental; Dental Bonding; Dental Caries; Dental Enamel; Humans; Microscopy, Electron, Scanning; Phosphoric Acids; Resin Cements; Surface Properties; X-Ray Microtomography
PubMed: 33760026
DOI: 10.2319/090120-761.1 -
PloS One 2018The great diversity of dinosaurian tooth shapes and sizes, and in particular, the amazing dental complexity in derived ornithischians has attracted a lot of attention....
The great diversity of dinosaurian tooth shapes and sizes, and in particular, the amazing dental complexity in derived ornithischians has attracted a lot of attention. However, the evolution of dental batteries in hadrosaurids and ceratopsids is difficult to understand without a broader comparative framework. Here we describe tooth histology and development in the "middle" Cretaceous ornithischian dinosaur Changchunsaurus parvus, a small herbivore that has been characterized as an early ornithopod, or even as a more basal ornithischian. We use this taxon to show how a "typical" ornithischian dentition develops, copes with wear, and undergoes tooth replacement. Although in most respects the histological properties of their teeth are similar to those of other dinosaurs, we show that, as in other more derived ornithischians, in C. parvus the pulp chamber is not invaded fully by the newly developing replacement tooth until eruption is nearly complete. This allowed C. parvus to maintain an uninterrupted shearing surface along a single tooth row, while undergoing continuous tooth replacement. Our histological sections also show that the replacement foramina on the lingual surfaces of the jaws are likely the entry points for an externally placed dental lamina, a feature found in many other ornithischian dinosaurs. Surprisingly, our histological analysis also revealed the presence of wavy enamel, the phylogenetically earliest occurrence of this type of tissue. This contradicts previous interpretations that this peculiar type of enamel arose in association with more complex hadrosauroid dentitions. In view of its early appearance, we suggest that wavy enamel may have evolved in association with a shearing-type dentition in a roughly symmetrically-enameled crown, although its precise function still remains somewhat of a mystery.
Topics: Amelogenesis; Animals; Dental Enamel; Dinosaurs; Fossils; Odontogenesis; Tooth
PubMed: 30403689
DOI: 10.1371/journal.pone.0205206 -
Journal of Oral Science 2020This study aims to evaluate the effect of mouth rinses on the color, microhardness, and surface roughness of tooth enamel. Sixty dental blocks were collected from human...
This study aims to evaluate the effect of mouth rinses on the color, microhardness, and surface roughness of tooth enamel. Sixty dental blocks were collected from human third molars and divided in five groups (n = 12): the control group (CG) without immersion in mouth rinse, Listerine Zero, Colgate Plax Fresh Mint, Listerine Whitening, and Colgate Luminous White. The groups were subjected to initial color analysis; the microhardness and roughness of the enamel surfaces were evaluated. Next, the samples were subjected to immersion in mouth rinses or brushing with conventional fluoride toothpaste (CG) according to the manufacturer's instructions; after a 12-week treatment, the color, microhardness, and roughness were once again assessed and compared with the initial analysis. Data were tabulated and analyzed through a two-way analysis of variance (ANOVA) (color and roughness) followed by Tukey's test. Microhardness was analyzed through the Kruskal-Wallis test followed by Dunn's test; the level of significance was 5%. All groups immersed in mouth rinses had a higher level of microhardness loss than CG; additionally, all groups showed changes in the enamel surface. Enamel surface loss was observed using a roughness test, and the mouth rinses promoted a higher level of color changes than CG. Given the results, it can be concluded that the mouth rinses led to significant changes in tooth enamel.
Topics: Dental Enamel; Humans; Mouthwashes; Tooth; Tooth Bleaching; Toothpastes
PubMed: 31996511
DOI: 10.2334/josnusd.18-0370 -
Molecules (Basel, Switzerland) Sep 2020Dental caries or tooth decay is a preventable and multifactorial disease that affects billions of people globally and is a particular concern in younger populations.... (Review)
Review
Dental caries or tooth decay is a preventable and multifactorial disease that affects billions of people globally and is a particular concern in younger populations. This decay arises from acid demineralisation of tooth enamel resulting in mineral loss from the subsurface. The remineralisation of early enamel carious lesions could prevent the cavitation of teeth. The enamel protein amelogenin constitutes 90% of the total enamel matrix protein in teeth and plays a key role in the biomineralisation of tooth enamel. The physiological importance of amelogenin has led to the investigation of the possible development of amelogenin-derived biomimetics against dental caries. We herein review the literature on amelogenin, its primary and secondary structure, comparison to related species, and its' in vivo processing to bioactive peptide fragments. The key structural motifs of amelogenin that enable enamel remineralisation are discussed. The presence of several motifs in the amelogenin structure (such as polyproline, N- and C-terminal domains and C-terminal orientation) were shown to play a critical role in the formation of particle shape during remineralization. Understanding the function/structure relationships of amelogenin can aid in the rational design of synthetic polypeptides for biomineralisation, halting enamel loss and leading to improved therapies for tooth decay.
Topics: Amelogenin; Amino Acid Motifs; Animals; Biomimetics; Cattle; Dental Caries; Dental Enamel; Durapatite; Humans; Leucine; Mice; Peptides; Protein Domains; Swine; Tyrosine
PubMed: 32937944
DOI: 10.3390/molecules25184214 -
ACS Nano Mar 2019Tooth enamel is a hard yet resilient biomaterial that derives its unique mechanical properties from decussating bundles of apatite crystals. To understand enamel crystal...
Tooth enamel is a hard yet resilient biomaterial that derives its unique mechanical properties from decussating bundles of apatite crystals. To understand enamel crystal nucleation and growth at a nanoscale level and to minimize preparation artifacts, the developing mouse enamel matrix was imaged in situ using graphene liquid cells and atomic resolution scanning transmission electron and cryo-fracture electron microscopy. We report that 1-2 nm diameter mineral precipitates aggregated to form larger 5 nm particle assemblies within ameloblast secretory vesicles or annular organic matrix subunits. Further evidence for the fusion of 1-2 nm mineral precipitates into 5 nm mineral aggregates via particle attachment was provided by matrix-mediated calcium phosphate crystal growth studies. As a next step, aggregated particles organized into rows of 3-10 subunits and developed lattice suprastructures with 0.34 nm gridline spacings corresponding to the (002) planes of apatite crystals. Mineral lattice suprastructures superseded closely matched organic matrix patterns, suggestive of a combination of organic/inorganic templates guiding apatite crystal growth. Upon assembly of 2-5 nm subunits into crystal ribbons, lattice fringes indicative of the presence of larger ordered crystallites were observed surrounding elongating crystal ribbons, presumably guiding the c-axis growth of composite apatite crystals. Cryo-fracture micrographs revealed reticular networks of an organic matrix on the surface of elongating enamel crystal ribbons, suggesting that protein coats facilitate c-axis apatite crystal growth. Together, these data demonstrate (i) the involvement of particle attachment in enamel crystal nucleation, (ii) a combination of matrix- and lattice-guided crystal growth, and (iii) fusion of individual crystals via a mechanism similar to Ostwald ripening.
Topics: Animals; Apatites; Cryoelectron Microscopy; Crystallization; Dental Enamel; Mice; Microscopy, Electron, Scanning Transmission; Particle Size; Surface Properties
PubMed: 30763075
DOI: 10.1021/acsnano.8b08668