New fossils of Miotragocerus gluten from the Lower Siwaliks, Pakistan

The five specimens of Miotragocerus gluten were collected from the Lower Siwalik outcrops nearby the villages Chabbar Sayadan and Phadial in Punjab, Pakistan. The newly discovered specimens include the two horn cores and isolated teeth. Miotragocerus gluten is the mediumsized bovids, having brachydont to the sub-hypsodont type of dentition. The cusps are elevated, and the crown is surrounded by a rugose enamel layer. The present study reveals the abundance of bovids in the middle Miocene deposits which indicates a grassland ecosystem in this area.

Developmental defect of email in children and adolescent: a review

ABSTRACT Developmental defect of enamel (DDE) is a defect on the surface of the enamel layer thatoccurs during tooth development due to various genetic and environmental factors. Defects that occurresult in changes in color and texture on the enamel surface so that it interferes with aesthetics. Thedefect level that happens can be classified based on the DDE index to determine the option of a casetreatment plan consisting of enamel microabrasion, conservative aesthetic restoration, and bleaching.This review aims to analyze and review studies related to DDE in primary and permanent teeth. Anelectronic search was conducted through PubMed/Medline, Google Scholar, Semantic Scholar,SpringerLink, and Wiley Online Library using the keywords “defect email”, “developmental defectemail”, and “defect on primary teeth” for research published between January 2011 and April 2020, thesame article was eliminated, the initial search resulted in a total of 55 articles. The exclusion of articleswas carried out based on the title and abstract so that finally, 45 relevant articles were obtained. Threestudies were included in this review for qualitative analysis. The results show that Enamel (DDE)Developmental defects can occur in both primary and permanent teeth with the same prevalence rate. KEYWORDS: Developmental Defect of Email (DDE), DDE Index, defect to primary teeth, defect topermanent teeth

Influence of Varying Dentin and Enamel Layer Thicknesses of Nano-composite Resins on Color Match between Lithium Disilicate Dental Ceramic and Composite Resins

Objectives: The aim of this study was to evaluate the influence of varying dentin and enamel layer thicknesses of two nano-composite resins on color match of composite resins and lithium disilicate dental ceramic. Materials and Methods: Twenty-six specimens of two types of nano-composite resins, Opallis and Vittra, were fabricated using the two-layered technique with different thickness ratios of enamel and dentin composites (A2 shade) with a total thickness of 1.2mm. Thirteen discs of the same shade and thickness of IPS e.max Press LT (low translucency) lithium disilicate dental ceramic were also fabricated. Specimen color was measured with a spectrophotometer. The difference in color (ΔE00) of composite and ceramic specimens, and the translucency parameter (TP) of all specimens were calculated. Data were analyzed using multi-factor ANOVA (P<0.05). Results: The color difference (ΔE00) values of composites and ceramic were not clinically acceptable in any areas of either of the two composites (ΔE00>2.25). But ΔE00 between the two composite resins was in the clinically acceptable range (ΔE00<2.25). The mean TP value of IPS e.max Press was greater than that of Vittra and lower than that of Opallis. Conclusion: In similar thicknesses, composite resins with any enamel/dentin thickness ratio could not successfully simulate the color and translucency of IPS e.max Press LT ceramic.

Amelogenesis Imperfecta: A Case Report

Amelogenesis imperfecta is a structural-developmental defect involving enamel. It may be hypoplastic, hypomaturation, or hypocalcified. Genetic mutation of enamel coding proteins noted in this heterogeneous group of hereditary disorder affecting both primary and permanent dentitions. Clinically the affected teeth depict discolouration, prone to disintegration and sensitivity. Radiological evaluation revealed very thin or absent of the enamel layer. Here, I am presenting a case report of amelogenesis imperfecta affecting a 19 year old, otherwise healthy, female patient. Key Words: Amelogenesis imperfecta, enamel, hypoplastic, Genetic mutation.

Morpho-Chemical Observations of Human Deciduous Teeth Enamel in Response to Biomimetic Toothpastes Treatment

Today, biomaterial research on biomimetic mineralization strategies represents a new challenge in the prevention and cure of enamel mineral loss on delicate deciduous teeth. Distinctive assumptions about the origin, the growth, and the functionalization on the biomimetic materials have been recently proposed by scientific research studies in evaluating the different clinical aspects of treating the deciduous tooth. Therefore, appropriate morpho-chemical observations on delivering specific biomaterials to enamel teeth is the most important factor for controlling biomineralization processes. Detailed morpho-chemical investigations of the treated enamel layer using three commercial toothpastes (Biorepair, F1400, and F500) were performed through variable pressure scanning electron microscopy (VP-SEM) and energy dispersive X-ray spectroscopy (EDS) on deciduous teeth in their native state. A new microscopy methodology allowed us to determine the behaviors of silicate, phosphate, and calcium contents from the early stage, as commercially available toothpastes, to the final stage of delivered diffusion, occurring within the enamel layer together with their penetration depth properties. The reported results represent a valuable background towards full comprehension of the role of organic–inorganic biomaterials for developing a controlled biomimetic toothpaste in biofluid media.

The hidden structure of human enamel

Enamel is the hardest and most resilient tissue in the human body. Enamel includes morphologically aligned, parallel, ∼50 nm wide, microns-long nanocrystals, bundled either into 5-μm-wide rods or their space-filling interrod. The orientation of enamel crystals, however, is poorly understood. Here we show that the crystalline c-axes are homogenously oriented in interrod crystals across most of the enamel layer thickness. Within each rod crystals are not co-oriented with one another or with the long axis of the rod, as previously assumed: the c-axes of adjacent nanocrystals are most frequently mis-oriented by 1°–30°, and this orientation within each rod gradually changes, with an overall angle spread that is never zero, but varies between 30°–90° within one rod. Molecular dynamics simulations demonstrate that the observed mis-orientations of adjacent crystals induce crack deflection. This toughening mechanism contributes to the unique resilience of enamel, which lasts a lifetime under extreme physical and chemical challenges.