amelo

What is the hardest tissue in the body?

Enamel

What is the primary function of enamel?

To cover the crown and provide shape and contour for the crowns.

What is the composition of enamel?

96-98% inorganic (hydroxyapatite), 2-4% organic (including water and proteins).

What are the main proteins found in enamel?

Amelogenin (immature fetal enamel) and enamelin (mature enamel protein).

How thick is enamel at the incisal edge?

Approximately 3 mm.

What is the primary mineral found in enamel?

Hydroxyapatite crystals (calcium phosphate).

What is the significance of the neonatal line in enamel?

It reflects physiological changes occurring around the time of birth and is the thickest and darkest stria of Retzius.

What is the role of ameloblasts in enamel formation?

They synthesize enamel and are lost after eruption.

What is gnarled enamel?

Enamel found in cusps and incisal edges, characterized by bundles of rods intertwining irregularly.

What is the structural characteristic of enamel that resembles tree rings?

Incremental lines of Retzius.

What are perikymata?

The external manifestations of the incremental lines of Retzius on the tooth surface.

What is the specific gravity of enamel?

2.8

What is the texture of enamel?

Smooth and glossy.

What is the arrangement of enamel crystals?

Long crystals arranged in rods, separated by interrod enamel.

What is the primary reason enamel is brittle?

Its high mineral content.

What optical phenomenon is produced by changes in direction between adjacent groups of enamel rods?

Hunter-Schreger bands.

What is the role of enamel proteins in mineralization?

They regulate mineralization and the growth in thickness and width of enamel crystals.

What is the significance of enamel tufts?

They are structural features in enamel that may indicate areas of stress or weakness.

What is the difference between enamel rods and interrod enamel?

Enamel rods are cylindrical structures made of long crystals, while interrod enamel has crystals running in a different direction.

What is the thickness of enamel over the facial and cervical margin?

Thinner compared to the crest of cusps.

What does the term 'incremental line of Retzius' refer to?

Dark lines extending from the dentinoenamel junction to the tooth surface, indicating enamel deposition.

What is the primary characteristic of the inner and outermost layers of enamel?

They are aprismatic.

What are enamel tufts?

Hypo-mineralized areas rich in enamel proteins that project from the DEJ into the inner 1/3 of enamel.

What is an enamel lamella?

A hypo-mineralized defect extending from the surface containing trapped organic material.

What is an enamel spindle?

The tip of an odontoblast process trapped in enamel.

What do striae of Retzius, enamel lamellae, and enamel tufts represent?

Areas of hypomineralized enamel containing trapped organic material.

What is the dentino-enamel junction (DEJ)?

The interface between enamel and dentin.

What is amelogenesis?

The process of enamel formation.

What occurs during the morphogenetic stage of enamel formation?

The shape of the crown is determined and preameloblasts are formed.

What happens during the organization and differentiation phase?

Peripheral cells of the dental papilla become odontoblasts and secrete dentin.

What is the secretory stage in enamel formation?

The stage where ameloblasts synthesize enamel proteins and begin enamel deposition.

What occurs during the maturation stage of enamel formation?

The matrix begins to mineralize after the full thickness of immature enamel is completed.

What is the protective stage in enamel formation?

The final effort of ameloblasts to lay down a protective layer called the primary enamel cuticle.

What is amelogenesis imperfecta?

A disturbance in the formation and maturation of the enamel matrix.

What is enamel hypoplasia?

Defective matrix formation with normal calcification, resulting in irregular and pitted enamel.

What is enamel hypocalcification?

Normal enamel formed in normal amounts but with disturbed mineralization, resulting in soft and opaque enamel.

What is attrition?

Physiologic wearing down of tooth structure due to mechanical forces from opposing teeth.

What is abrasion in dental terms?

Pathologic mechanical wear of tooth structure.

What is abfraction?

Pathological loss of tooth substance caused by biomechanical loading forces.

What causes erosion of teeth?

Chemical wearing of teeth, commonly due to acid foods and drinks.

What is acid etching?

Application of phosphoric acid to enamel to create microporosities.

What are dental caries?

The action of acids formed by microorganisms that dissolve enamel.