Pretend you are a teacher preparing a quiz for the text I will provide. 
            Each quiz question should follow the format below. 
            Ensure that you carefully recheck the questions and answers for accuracy. 
            The output should be a ready-to-use list of dictionaries for the Python eval function:

            [

                    "question": "WRITE THE QUESTION HERE",
                    "options": ["A) OPTION_1", "B) OPTION_2", "C) OPTION_3", "D) OPTION_4"],
                    "answer": INDEX_OF_CORRECT_ANSWER_IN_OPTIONS_LIST,
                    "explanation": "EXPLAIN WHY THE ANSWER IS CORRECT"

            ]

            Text:
            t it is 4%
less
mineralized,
and
the
collagen
fiber
orientation is perpendicular rather than parallel
to the DEJ.
1. Primary Dentin
www.drcube.org
The odontoblasts produce primary dentin, mainly
intertubular dentin, at a rate of 4 to 8 μm/day.
Approximately 2 to 3 years following tooth
eruption. The bulk of dentin surrounding the pulp
chamber and canal systems, termed circumpulpal
dentin.
The synthesis of dentin then slows to 1 to 2
μm/day,
decreasing
in
rate
with
age
but
continuing as long as the tooth is vital.
www.drcube.org
This is a slowly formed dentin of 1 to 2 μm/day,
decreasing in rate with age but continuing as long
as the tooth is vital.
This continued deposition of secondary dentin
led to constriction in the dimensions of the pulp
chamber.
In response to mild occlusal stimulus, secondary
dentin is mainly deposited in the pulp horns and
on the roof and floor of the pulp chamber so
after many decades the chamber becomes quite
narrow occluso-gingivally.
2. Secondary Dentin
www.drcube.org
This constriction in pulp chamber size reduced the
possibility of pulp exposure in old patients during
cavity or crown preparation.
The dentist must pay attention for the size and
location of the pulp chamber to decide the design
of the preparation and placement of retentive
features such as pins.
www.drcube.org
Sclerotic Dentin
(Transparent or Peritubular dentin)
This type of dentin results from aging or mild
irritation (such as slow caries, attrition, abrasion,
erosion and occlusal trauma) and causes a change in
the composition of the primary dentin.
The tubular content appears to be replaced by
calcified
material
that
obliterates
the
tubules,
progressing from the DEJ pulpaly.
The tubules become progressively hypermineralized
and, with constriction of the lumen and less
permeable. The sclerotic dentin is harder, denser,
less sensitive and more protective of the pulp
against subsequent irritation.
www.drcube.org
Sclerosis resulting from aging is (physiological dentin
sclerosis) and that resulting from mild irritation
called (reactive dentine sclerosis).
The combination of peritubular wall thickness and
intratubular
crystals
creates
a
zone
of
hypermineralized dentin beneath exposed or carious
dentin, the zone of sclerosis or translucent zone.
Sclerotic dentin is frequently found beneath both
active caries lesions and restorations and is an
important defense reaction of the hard tissues
because it limits the permeability of dentin.
www.drcube.org
Reparative dentin (tertiary dentin)
Intense traumatic insult (injury) to the tooth, whether
caused by bacterial penetration associated with
caries, or heat and trauma from a dental bur, may be
severe enough to destroy the supporting odontoblasts
in the affected location. Within 3 weeks, fibroblasts or
mesenchymal cells of the pulp are converted or
differentiated to simulate the activities of original
odontoblast, and form irregularly organized atubular
dentin called reparative dentin.
www.drcube.org
Tertiary
Seco

            Quiz: