Enamel-3

Answers for Enamel -3

Maximum thickness of enamel in deciduous dentition in molar cusps	1.3 mm
Volume of water in enamel	5 to 10%. This is crucial as a lot of ions cross in to tooth in liquid medium
Water in enamel is in form of	hydration layer coating enamel crystals and filling enamel defects
Prism patterns in human enamel	Three types are seen - Pattern 1 - circular; pattern 2 - prism arranged in parallel rows; pattern 3 - arranged in staggered row "key hole" pattern
Basic unit of enamel	Enamel prism
Organic material are often accommodated along enamel prism boundary because of	Microporosity
The predominant pattern of arrangement of enamel rods in human is	Type III or key hole pattern
Key hole pattern or type III pattern is made by	Large ameloblasts
Small ameloblasts produce	Pattern II or parallel arranged fashion of enamel crystallites
Enamel between prisms are called	Interprismatic enamel
Why does interprismatic enamel have different optical property	Owing to crystal deviation by 40 to 60 degrees in orientation. Abnormal abrupt change of orientation responsible for refraction of light
The angle at which interprismatic crystallites cross prisms is	60 degrees
Stacks of ______enamel prisms follows are unidirectional after which they follow different direction	10 to 13 layers
Transversely sectioned zones in Hunter-Schereger bands are	Diazones
Longitudinally sectioned zones in Hunter-Schereger bands are	Parazones
The average width of Hunter-Schereger bands are	50 micrometers
The angle between diazones and parazones of enamel is about	40 degrees
Where will be Hunter -Schreger bands be absent	when all enamel rods runs in same direction, as in outermost 25% of enamel, the bands will be absent
width of non-prismatic enamel in a newly erupted teeth	Deciduous 20 - 100 micrometers and permanent teeth 20 to 70 micrometers. Enamel crystallites are aligned at right angle to surface and hence parallel to each other.
why is the outer most layer of enamel highly mineralized	Remineralization by saliva; absence of prism boundaries.