What is the composition of dentin?
Dentin is approximately 55 vol% mineral, 30 vol% organic material (primarily type I collagen), and 15 vol% fluid [46], but dentin composition varies with the age and tooth type. The organic portion of collagen is surrounded by water, and hydrogen bonding exists between the strands of the collagen [48].
What is matrix in dentin?
Dentin is primarily composed of hydroxyapatite crystals within a rich organic matrix. The organic matrix comprises collagenous structural components, within which a variety of bioactive molecules are sequestered.
What percent of dentin is hydroxyapatite?
By volume, 45% of dentin consists of the mineral hydroxyapatite, 33% is organic material, and 22% is water. Yellow in appearance, it greatly affects the color of a tooth due to the translucency of enamel. Dentin, which is less mineralized and less brittle than enamel, is necessary for the support of enamel.
What is reactionary dentin?
Reactionary dentin is formed in response to a carious decay, to excessive abrasion, or to the cytotoxic effects of monomers released by a restorative material. This is how the pulp limits undesirable noxious effects.
What is the thickness of dentin?
The mean values of dentin thickness observed for first molars were 2430 mm (buccal), 1.869 mm (lingual), 1.655 mm (mesial) and 1.664 mm (distal). For second molars the dentin thickness presented 3.006 mm (buccal), 2730 mm (lingual), 2130 mm (mesial) and 2192 mm (distal).
What is translucent dentine?
Sclerotic dentine: Sclerotic (or translucent) dentine arises because the dentinal tubules have been completely occluded by the laying down of additional peritubular dentine within the tubules by the odontoblasts.
What are the 3 types of dentin?
Types. There are three different types of dentin which include primary, secondary and tertiary. Secondary dentin is a layer of dentin which is produced after the tooth’s root is completely formed. Tertiary dentin is created in response to a stimulus, such the presence of tooth decay or wear.
Where is dentin matrix acidic phosphoprotein?
The gene encoding dentin matrix acidic phosphoprotein-1, DMP1, is located within 150 kbs of the bone sialoprotein locus and within 490 kbs of the SPP1 locus for osteopontin on chromosome 4q21. The gene contains six exons [422].
What is Peritubular dentin?
Peritubular dentin (PTD) is a relatively dense mineralized tissue that surrounds the tubules of coronal tooth dentin. It is composed mainly of crystals of carbonated apatite together with a small amount of collagen.
How many elements are in hydroxyapatite?
Hydroxyapatite (HA) is an inorganic mineral that has a typical apatite lattice structure as (A10(BO4)6C2) where A, B, and C are defined by Ca, PO4, and OH. Pure HA contains 39.68% by weight calcium and 18% by weight phosphorus resulting in a Ca/P mole ratio of 1.67.
What is PDL in dentistry?
The periodontal ligament, commonly known as the PDL, is a soft connective tissue between the inner wall of the alveolar socket and the roots of the teeth. It consists of collagen bands (mostly type I collagen) connecting the cementum of teeth to the gingivae and alveolar bone.
What is the structure of dentin?
Dentin is a mineralized dental tissue underlying the outer enamel that has a peculiar micro morphology. It is composed of micrometer sized tubules that are surrounded by a highly mineralized structure, called peritubular dentin (PTD), and embedded in a collagen-rich matrix, named intertubular dentin.
Are dentin extracellular matrix molecules involved in dentinogenesis?
Thirdly, we study the composition and functions of dentin extracellular matrix (ECM) molecules implicated in dentinogenesis. As structural proteins they are mineralization promoters or inhibitors.
What is peritubular dentin made of?
It is composed of micrometer sized tubules that are surrounded by a highly mineralized structure, called peritubular dentin (PTD), and embedded in a collagen-rich matrix, named intertubular dentin. The PTD has been thought to be composed of a highly mineralized collagen-free organic matrix with unknown composition.
What are the regional variations in dentin structure and composition?
Regional variations in dentin structure and composition. Peripherally, mineralisation can be seen to be incomplete, whereas centrally the mineralising front shows ongoing mineralising. The innermost layer of dentin is known as predentin, and is the initial dentin matrix that is laid down prior to mineralisation.