Lecture 3

Question 1

3 STAGES OF TOOTH DEVELOPMENT

Answer 1

1. ) BUD STAGE
2. ) CAP STAGE
3. ) BELL STAGE

Question 2

BUD STAGE

Answer 2

NO CLEAR ARRANGEMENT OF CELLS

DIFFERENTIATION OF CELLS INTO THE INNER AND OUTER DENTAL LAMINA

Question 3

CAP STAGE

Answer 3

1ST SIGN OF ARRANGEMENT OF CELLS
TOOTH BUD BEGINS TO GROW AROUND THE MESENCHYME CELL FORMATION YIELDING A CAP SHAPE WHICH LATER BECOMES ENAMEL
STERIRIDICULUM DIFFERENTIATES BETWEEN INNER AND OUTER LAYERS

Question 4

BELL STAGE

Answer 4

HISTO AND MORPHODIFFERENTIATION TAKES PLACE

CELLS DIFFERENTIATE INTO (1) AMELOBLASTS AND (2) ODONTOBLASTS (I.E. FORMATION OF DENTAL HARD TISSUE)

Question 5

AMELOBLASTS

Answer 5

FORM ENAMEL (COMES FROM INNER EPITHELIUM)

Question 6

ODONTOBLASTS

Answer 6

FROM DENTIN (COMES FROM PROLIFERATED MESENCHYMAL CELL FORMATION)

Question 7

ENAMEL

Answer 7

OUTER LAYER OF THE TOOTH STRUCTURE (95% HAP)
VERY HARD AND BRITTLE W/ NO INNERVATION OR CELL TISSUE (I.E. NO SENSATION)
CAN NOT BE REGENERATED
DEMINERALIZES AT pH 5.5
CRYSTALLITE IN NATURE - MADE OF INTERLOCKING RODS

Question 8

PHYSICAL DEGENERATION OF ENAMEL STRUCTURE

Answer 8

1. ) ABRASION - MECHANICAL WEAR
2. ) ATTRITION - TOOTH-TO-TOOTH CONTACT
3. ) ABFRACTION - LESIONS IN TOOTH CAUSED BY BOTH 1 AND 2

Question 9

CHEMICAL DEGRADATION OF ENAMEL STRUCTURE

Answer 9

EROSION BY EXTRINSIC OR INTRINSIC ACID

Question 10

DENTIN

Answer 10

SOFTER THAN ENAMEL (70% HAP)
DEMINERALIZES AT pH 6.5 (MUCH MORE SENSITIVE TO ACIDITY)
NO INNERVATION BUT STILL HAS SENSITIVITY
REGENERATED THROUGHOUT LIFE

Question 11

1˚ DENTIN

Answer 11

FORMS INITIAL SHAPE OF THE TOOTH

Question 12

2˚ DENTIN

Answer 12

DEPOSITED AFTER FORMATION OF 1˚ DENTIN ON ALL INTERNAL ASPECTS OF THE PULP CAVITY

Question 13

3˚ DENTIN (REPARATIVE DENTIN)

Answer 13

ACTS AS A REPLACEMENT OF ODONTOBLASTS IN RESPONSE TO MODERATE LEVELS OF DEGRADATION

Question 14

DENTINAL TUBULES

Answer 14

CONNECT DENTIN AND PULP W/ PARALLEL S-SHAPED TUBES CONTAINING FLUID AND SMALL NERVE FIBERS - REASON THAT WE CAN DETECT STIMULI (TEMPERATURE AND PRESSURE) VIA FLUID W/IN TUBULES CONDUCTING THE SIGNAL
2-3mm AT ENAMEL SURFACE
3-5mm AT DENTINAL SURFACE

Question 15

HYDROXYAPETITE

Answer 15

ABLE TO RESPOND TO SIGNALS OF EXTERIOR STIMULATION (PREGNANCY, GRAVITY, EXERCISE)
ACID DRINKS CAUSE HAP TO COME TO ENAMEL SURFACE AND IT IS PHOSPHORYLATED AND HAP IS BROKEN DOWN

Question 16

PERIKYMATA

Answer 16

PITS AROUND THE LONG PRISMS OF TOOTH ENAMEL INDICATING SITES WHERE AMELOBLASTS MADE CONTACT W/NEIGHBORING CELLS