Dental enamel structure in long-nosed armadillos (Xenarthra: Dasypus) and its evolutionary implications

Abstract Most xenarthrans have a reduced and simplified dentition that lacks enamel. However, the presence of prismatic enamel has been recorded in the Eocene armadillos Utaetus buccatus (Euphractinae) and Astegotherium dichotomus (Astegotheriini). Among extant xenarthrans, the occurrence of enamel has been recognized only in the long-nosed armadillo, Dasypus novemcinctus (Dasypodinae), but its microstructure has never been described. In this contribution, we analyse the enamel microstructure in deciduous and permanent teeth of four Dasypus species. In deciduous molariform teeth of some species, we identify an apical cap of vestigial enamel (without crystalline structure), interpreted as an amorphous ameloblastic secretion. In permanent teeth, a thin layer of true enamel is found in the apical portion of unworn molariforms. The enamel is prismatic in D. novemcinctus, but in Dasypus hybridus, Dasypus sabanicola and Dasypus punctatus it is prismless. Taking into account the Eocene species of armadillos, the ancestral condition of enamel in cingulates could have been more complex (as in other placentals) and undergone progressive reduction, as shown in the Dasypus lineage. In light of previous genetic and developmental studies, we review and briefly discuss the processes that can account for the reduction/loss of enamel in extant and extinct armadillos. The retention of enamel and the fact that this genus is the only living xenarthran with two functional generations of teeth support the early divergence of the Dasypus lineage among living cingulates. This is in agreement with morphological and molecular analyses.

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A Comparative Evaluation of Nanohydroxyapatite-Enriched Hydrogen Peroxide Home Bleaching System on Color, Hardness and Microstructure of Dental Enamel

Materials ◽

10.3390/ma14113072 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3072

Author(s):

Riccardo Monterubbianesi ◽

Vincenzo Tosco ◽

Tiziano Bellezze ◽

Giampaolo Giuliani ◽

Mutlu Özcan ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Particle Diameter ◽

Dental Enamel ◽

Sem Analysis ◽

Control Group ◽

Average Particle ◽

Color Analysis ◽

Enamel Microstructure ◽

Prismatic Structure ◽

20 Nm

This study aimed to evaluate two hydrogen peroxide (HP)-based at-home bleaching systems in order to analyze whether nano-hydroxyapatite (nHA) addition may represent a reliable and safe solution for tooth whitening without altering dental microstructure and hardness. Human third molars (N = 15) were treated with two bleaching agents, one containing 6%HP (6HP) and the other 6% HP nHA-enriched (6HP-nHA) with average particle diameter ranging from 5–20 nm. Their effects on enamel were assessed using a spectrophotometer, Vickers microhardness (VMH) test and Scanning Electron Microscopy (SEM), comparing the treated groups with the non-treated control group (CTR). Color analysis revealed improvement in whiteness in both groups compared to CTR. VMH test results showed no differences among the groups. SEM analysis highlighted no evident changes in the enamel microstructure of tested groups compared to CTR. At high magnification, in 6HP group, a slight increase in irregularities of enamel surface morphology was observed, while 6HP-nHA group displayed removal of the aprismatic layer but preservation of the intact prismatic structure. These results suggest that the 6HP-nHA agent may be recommended to provide reliable whitening treatment, without damaging the enamel micromorphology and hardness.

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Efficacy of In-office Bleaching on Microhardness of Permanent Teeth with Antioxidant Re-hardening

The Open Dentistry Journal ◽

10.2174/1874210601913010436 ◽

2019 ◽

Vol 13 (1) ◽

pp. 436-442

Author(s):

Esra G Çakir ◽

Suat Özcan ◽

Ibrahim Tulunoglu ◽

Mine B. Üçtaşli ◽

Ozlem Tulunoglu

Keyword(s):

Resin Composite ◽

Calcium Nitrate ◽

Third Molar ◽

Permanent Teeth ◽

Sodium Ascorbate ◽

Micro Hardness ◽

Bleaching Procedure ◽

Enamel Structure ◽

Hardness Values ◽

Bleaching Treatment

Background: Bleaching procedures affect surface enamel structure and decrease its bonding ability to resin composite restorative materials. The application of re-hardening materials to bleached enamel surfaces may prevent this decrease in micro-hardness. Objective: This in-vitro study aims to evaluate the surface micro hardness of human teeth enamel subjected to bleaching with Zoom Advanced Power 2 AP (Phillips, USA), and Opalescence Boost (Ultradent, USA) and compare the re-hardening effects of 10% Sodium Ascorbate, 2% acidulated phosphate fluoride gel, and a 5% Potassium nitrate 0.22% Sodium Fluoride + Calcium Nitrate gel. Methods: Ninety human third molar teeth were used. The specimens were randomly assigned to 5 groups. After the bleaching procedure, the specimens were treated with APF, Sodium Ascorbate or Relief gel as re-hardening agents with 30 teeth in each group. Enamel micro-hardness was measured with Vickers Micro-hardness Tester. The data were evaluated with Kolmogorov-Simirnov, one-way ANOVA, Dunnett’s test, post-hoc Tukey and T-tests. Results: Statistical analysis revealed no significant differences among initial enamel groups’ micro-hardness values (P>.05); however, significant differences occurred between initial and after bleaching treatment group value for G3 (P< .05). After re-hardening, only the Sodium Ascorbate group showed a statistically significant increase with hardness values (P< .05) for G4 and G5. Conclusion: Bleaching treatment conducted with light had no adverse effect on enamel micro-hardness. Sodium Ascorbate can be useful after bleaching to change the adverse effects of bonding on the enamel.

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How the tooth got its stripes: patterning via strain-cued motility

Journal of The Royal Society Interface ◽

10.1098/rsif.2013.0266 ◽

2013 ◽

Vol 10 (84) ◽

pp. 20130266 ◽

Cited By ~ 15

Author(s):

Brian N. Cox

Keyword(s):

Morphological Characteristics ◽

Dental Enamel ◽

Diffusion Reaction ◽

Enamel Microstructure ◽

Sliding Motion ◽

Chemical Signalling ◽

Simple Rules ◽

Mouse Incisor ◽

Cell Trajectories ◽

And Diffusion

We hypothesize that a population of migrating cells can form patterns when changes in local strains owing to relative cell motions induce changes in cell motility. That the mechanism originates in competing rates of motion distinguishes it from mechanisms involving strain energy gradients, e.g. those generated by surface energy effects or eigenstrains among cells, and diffusion–reaction mechanisms involving chemical signalling factors. The theory is tested by its ability to reproduce the morphological characteristics of enamel in the mouse incisor. Dental enamel is formed during amelogenesis by a population of ameloblasts that move about laterally within an expanding curved sheet, subject to continuously evolving spatial and temporal gradients in strain. Discrete-cell simulations of this process compute the changing strain environment of all cells and predict cell trajectories by invoking simple rules for the motion of an individual cell in response to its strain environment. The rules balance a tendency for cells to enhance relative sliding motion against a tendency to maintain uniform cell–cell separation. The simulations account for observed waviness in the enamel microstructure, the speed and shape of the ‘commencement front’ that separates domains of migrating secretory-stage ameloblasts from those that are not yet migrating, the initiation and sustainment of layered, fracture-resistant decussation patterns (cross-plied microstructure) and the transition from decussating inner enamel to non-decussating outer enamel. All these characteristics can be correctly predicted with the use of a single scalar adjustable parameter.

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Mineralization of Eroded Dental Enamel Seeded with Fluoride and a Tricalcium Phosphate Ternary Biomaterial

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.76.42 ◽

2010 ◽

Vol 76 ◽

pp. 42-47 ◽

Cited By ~ 3

Author(s):

Robert L. Karlinsey ◽

Allen C. Mackey ◽

Emily R. Walker ◽

Trenton J. Walker ◽

Christabel X. Fowler

Keyword(s):

Ir Spectroscopy ◽

Dose Response ◽

Tricalcium Phosphate ◽

Phosphate Uptake ◽

Dental Enamel ◽

Enamel Microstructure ◽

Fluoride Uptake ◽

Therapeutic Applications ◽

Innovative Biomaterials ◽

Bovine Enamel

The inability to sufficiently prevent and/or repair chemically-etched dental enamel serves as one example that underlines the importance and need for the development of innovative biomaterials for therapeutic applications. In this work we explored the seeding capability of 225 ppm and 1100 ppm fluoride with and without a novel β-tricalcium phosphate-silica-urea (TCP-Si-Ur) biomaterial (concentrations of 20, 40, 80, and 200 ppm) to mineralize into acid-etched bovine enamel. The nature of the mineralization was evaluated by measuring the fluoride and phosphate uptake into the eroded enamel, as well as the orthophosphate microstructure using infrared (IR) spectroscopy. These enamel fluoride uptake and IR experiments revealed a fluoride dose response exists for eroded enamel treated with 225 and 1100 ppm F. The inclusion of 20, 40, and 80 ppm TCP-Si-Ur with 225 ppm F was similar to 225 ppm F alone and did not produce a fluoride uptake dose response; however, 200 ppm TCP-Si-Ur combined with 1100 ppm F improved raw fluoride uptake relative to 1100 ppm F. Furthermore, we found the combination of either 225 ppm or 1100 ppm fluoride plus TCP-Si-Ur at different loading levels leads to unique and significant mineral integration into the PO4 enamel network, including the formation of P-F bonds. The observations reported herein demonstrate the combination of fluoride plus a novel TCP-Si-Ur biomaterial produces synergistic mineralization and bears significantly on eroded enamel microstructure.

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The impact of histopathological celiac disease activity on dental enamel defects and dental caries

Journal of Baghdad College of Dentistry ◽

10.26477/jbcd.v32i1.2758 ◽

2020 ◽

Vol 32 (1) ◽

pp. 51-56

Author(s):

Zainab Q Al-Obaidi ◽

Nada J Radhi

Keyword(s):

Celiac Disease ◽

Dental Caries ◽

Disease Activity ◽

Villous Atrophy ◽

Dental Enamel ◽

Permanent Teeth ◽

Caries Experience ◽

Entire Body ◽

Enamel Defects ◽

The Impact

Background: Celiac disease is an autoimmune chronic disease that affects the human’s intestine and subsequently reflects its effect on the entire body health by retardation the absorption and immune mediated complications cause the involvement of oral health. The present study intended to evaluate the impact of the histopathological disease activity upon dental enamel defects and dental caries. Subjects and methods: Forty celiac-diseased patients aged 7-11 years were collected from 3 different teaching hospitals in Baghdad classified by means of the histopathological activity of the intestinal disease according to modified Marsh-Rostami classification. Dental enamel defects were measured by Aine’s classification, while dental caries experience and severity were measured using d1-4mfs/t and D1-4MFS/T. Results: The majority of the sample came with partial villous atrophy of the small intestine (Marsh III-a) and almost half of the sample were with no celiac disease specific dental enamel defects (Aine’s 0), while Aine’s I was the most predominant than Aine’s II. Most missed surfaces due to dental caries in permanent teeth came with Marsh II. Conclusion: The more the severity of celiac disease histopathological activity the more the severity of celiac specific dental enamel defects and the less experienced dental caries. Keywords: Celiac disease, histopathological activity, dental enamel defects, dental caries.

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Restoration of Esthetics and Function in a Patient with Amelogenesis Imperfecta

International Journal of Prosthodontics and Restorative Dentistry ◽

10.5005/jp-journals-10019-1142 ◽

2015 ◽

Vol 5 (4) ◽

pp. 118-121

Author(s):

Vaibhao Ishwar Shambharkar ◽

Jasmeet Singh Chandhok ◽

Deepika Thosre Chandhok

Keyword(s):

Social Withdrawal ◽

Financial Burden ◽

Clinical Findings ◽

Amelogenesis Imperfecta ◽

Permanent Teeth ◽

Gingival Hyperplasia ◽

Enamel Structure ◽

Short Period ◽

Systemic Disorder ◽

And Function

ABSTRACT An unpleasant smile will not only hamper the looks of the person but also leaves a social withdrawal from the society specially for teenagers. Amelogenesis imperfecta (AI) is one such condition which affects not only the teeth but to overall social and psychological growth of a person. This clinical case deals with step-by-step procedures involved with multidisciplinary approach to deal with such cases in a short period of time with reduced financial burden over the patient. Amelogenesis imperfecta is a heterogeneous inherited disorder that disturbs the developing enamel structure and exists independent of any related systemic disorder. It affects both the primary and permanent dentitions. Transmission of the gene is autosomal dominant, recessive or X-linked mode of inheritance. Clinical findings of AI include Enamel deficiencies, pulpal calcification, root malformations, failed tooth eruption, impaction of permanent teeth, progressive root and crown resorption, congenitally missing teeth, tooth sensitivity. Due to reduced enamel thickness, the teeth are undersized, with lack of contact between adjacent teeth, poor oral hygiene and mouth breathing with associated gingivitis and gingival hyperplasia may also be seen. How to cite this article Chandhok JS, Chandhok DT, Shambharkar VI. Restoration of Esthetics and Function in a Patient with Amelogenesis Imperfecta. Int J Prosthodont Restor Dent 2015;5(4):118-121.

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Use of Antibiotics in early Childhood and Dental Enamel Defects in 6¬ to 12¬year¬old Children in Primary Health Care.

Acta Odontológica Latinoamericana ◽

10.54589/aol.33/1/006 ◽

2020 ◽

Vol 33 (1) ◽

pp. 6-13

Author(s):

Daniel Faustino-Silva ◽

Ariston Rocha ◽

Bruno da Rocha ◽

Caroline Stein

Keyword(s):

Health Care ◽

Early Childhood ◽

Primary Health Care ◽

Dental Enamel ◽

Permanent Teeth ◽

Chi Square ◽

Antimicrobial Drugs ◽

Enamel Defects ◽

Exact Test ◽

Primary Health

Dental enamel defects (DED) are lesions that occur due several factors. Proper care is needed to promote their treatment and prevention. The aim of this study was to evaluate the occurrence of DED in permanent teeth of children who used antimicrobial drugs in the first four years of life. This is a crosssectional study carried out in a Primary Health Care (PHC) service, which included children from six to 12 years of age. DED were evaluated by oral examination, and data on the use of antimicrobials in early childhood were collected based on medical records. Data were analyzed with the chi-square test and Fisher's exact test. The sample included 144 children. In relation to DED, 50% (72) and 20.1% (29) presented opacity and hypoplasia, respectively. Amoxicillin was the most frequently prescribed drug, followed by sulfamethoxazole + trimethoprim. Among the children, 78.5% (113) were prescribed antimicrobial drugs at least once during the first 4 years of life, and 55% (79) of them presented some type of DED. There was no statistically significant association between the variables analyzed. In conclusion, there was high prevalence of children with DED, and amoxicillin was the most commonly prescribed antibiotic.

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Associating the Presence of Structural Defects in Dental Enamel with Children's Health History

Journal of Health Sciences ◽

10.17921/2447-8938.2021v23n2p116-120 ◽

2021 ◽

Vol 23 (2) ◽

pp. 116-120

Author(s):

Jéssica Crispim ◽

Maria Gisette Arias Provenzano ◽

Adilson Luiz Ramos ◽

Gabriela Cristina Santin ◽

Marina de Lourdes Calvo Fracasso

Keyword(s):

Tooth Enamel ◽

Dental Enamel ◽

Positive Association ◽

Structural Defects ◽

Permanent Teeth ◽

Dental Anomalies ◽

Enamel Hypoplasia ◽

Chi Square ◽

Enamel Defects ◽

Respiratory Problems

AbstractThe enamel defects, hypoplasia and hypo mineralization, are classified as dental anomalies of structure, being frequently found in deciduous and permanent dentitions, since the permanent teeth and second deciduous molars finish their total mineralization after the age of three. The aim of the present study was to identify the presence of hypo mineralization and/or enamel hypoplasia and to associate it with respiratory problems in infant patients. Of the 90 patients evaluated, it was found that 23 male children (57.5%) and 22 female children (44%) had defects in the structure of tooth enamel. Most children were born by cesarean operation (64.4%), with no complications during birth (90.0%), 12.2% of children had dental anomalies (agenesis, ectopic canine, ankylosis, fusion, conoid tooth, and macrodontia, only 7 children showed an association between dental anomalies and enamel defects. Regarding respiratory problems that occurred up to 3 years of age, 38.9% had an episode of asthma, bronchitis, sinusitis, rhinitis, or pneumonia, and 55% had similar results at the current age. There was a positive association (Chi-square tests) between the presence of changes in the structure of tooth enamel and the presence of respiratory problems up to 3 years of age (p <0.001). It is concluded, therefore, that the presence of respiratory problems in early childhood, can interfere in amelogenesis, providing disturbances for the formation of normal enamel, causing defects or irregularities in the surface of the dental enamel, such as hypoplasias and hypo mineralization. Keywords: Dental Enamel Hypoplasia. Dental Enamel. Tooth Abnormalities. ResumoOs defeitos de esmalte, hipoplasia e hipomineralização, são classificados como anomalias dentárias de estrutura, sendo encontrados com frequência nas dentições decídua e permanente, já que os dentes permanentes e segundos molares decíduos finalizam sua total mineralização após os três anos de idade. O objetivo do presente estudo foi identificar a presença de hipomineralização e/ou hipoplasia de esmalte, e associá-la com problemas respiratórios no paciente infantil. Dos 90 pacientes avaliados, constatou-se que 23 crianças do gênero masculino (57,5%) e 22 do gênero feminino (44%) apresentaram defeitos na estrutura do esmalte dentário. A maioria das crianças nasceu de parto cesária (64,4%), sem complicação no parto (90,0%), 12,2% das crianças apresentaram anomalias dentárias (agenesia, canino ectópico, anquilose, fusão, dente conóide e macrodontia), somente 7 crianças apresentaram associação entre anomalias dentárias e defeitos de esmalte. Em relação à problemas respiratórios ocorrido até aos 3 anos de idade 38,9% apresentaram algum episódio de asma, bronquite, sinusite, rinite ou pneumonia e 55% apresentaram resultados semelhantes na idade atual. Houve associação positiva (Testes Qui Quadrado) entre a presença de alterações na estrutura do esmalte dentário e presença de problemas respiratórios até os 3 anos de idade (p<0,001). Conclui-se, portanto, que a presença de problemas respiratórios na primeira infância, podem interferir na amelogênese, proporcionando distúrbios para formação do esmalte normal, causando defeitos ou irregularidades na superfície do esmalte dentário, como hipoplasias e hipomineralizações. Palavras-chave: Hipoplasia do Esmalte Dentário. Esmalte Dentário. Anormalidades Dentárias.

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Molar-incisor hypomineralisation (MIH) – aetiology, clinical picture, treatment

Nowa Stomatologia ◽

10.25121/ns.2019.24.1.8 ◽

2019 ◽

Vol 24 (1) ◽

Author(s):

Sylwia Kuderewska ◽

Monika Stawiecka ◽

Renata Milewska ◽

Anna Kuźmiuk ◽

Ewa Chorzewska

Keyword(s):

Clinical Picture ◽

Dental Enamel ◽

Permanent Teeth ◽

Molar Incisor Hypomineralisation ◽

Pubmed Database ◽

Tissue Reconstruction ◽

Permanent Molars ◽

Severity Of The Disease ◽

Incisor Hypomineralisation ◽

First Permanent Molars

Introdution. Molar-incisor hypomineralisation is a disorder of dental enamel of a systemic origin. It may affect one or all four first permanent molars, and often involves permanent incisors. Aim. The aim of this study was to present views on aetiology, clinical picture and treatment of molar-incisor hypomineralisation. Material and methods. PubMed database was reviewed for years 2003-2017, the search criteria were: “molar incisor”, “hypomineralisation”, “permanent teeth”. Results. The aetiology of MIH is multifactorial and not fully explained. Authors agree that the general health during the first 3-4 years of life has a major impact on this disorder. The clinical picture includes demarcated white, yellow or brown tissue spots, and increased porosity of the enamel. Enamel damage and defects can also occur. Therapeutic management depends on the severity of the disease and includes intensive prevention, hard tissue reconstruction, and extractions. Conclusions. Due to the increasing prevalence of this disorder, special attention should be paid to children whose health status is or was bad in the first 3-4 years of life. They are at a higher risk for this condition.

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