Lecture 10

Question 1

POST-NATAL GROWTH OF THE MAXILLA

Answer 1

DEVELOPMENT AND GROWTH ARE LITTLE AFFECTED BY 2˚ CARTILAGE

1. ) ACCESSORY CARTILAGENEOUS CENTERS APPEAR IN THE REGION OF FUTURE ZYGOMATIC PROCESSES
2. ) IN MID-LINE OF DEVELOPING HARD PALATE BETWEEN PALATINE PROCESSES ACCESSORY CARTILAGENOUS CENTERS APPEAR
3. ) SMALL AREAS OF 2˚ CARTILAGE APPEAR ALONG GROWING MARGIN OF THE ALVEOLAR PLATE

Question 2

GROWTH PROCESSES OF THE MAXILLA

Answer 2

1. ) SUTURAL GROWTH
2. ) LATERAL GROWTH
3. ) ANTEROPOSTERIOR GROWTH
4. ) DISPLACEMENT PROCESSES

Question 3

SUTURAL GROWTH OF THE MAXILLA

Answer 3

CONTINUES UNTIL ~10 Y.O. THEN BECOMES LESS SIGNIFICANT
MAXILLA ARTICULATES W/ OTHER SKULL BONES BY 4 MAIN SUTURES
1.) FRONT-MAXILLARY SUTURE
2.) ZYGOMATICOMAXILLARY SUTURE
3.) ZYGOMATICOTEMPORAL SUTURE
4.) PTERYGOPALATINE SUTURE
GROWTH AT THESE SUTURES PUSHES THE MAXILLA FORWARD AND DOWNWARD => ANTEROPOSTERIOR GROWTH

Question 4

LATERAL GROWTH OF THE MAXILLA

Answer 4

OCCURS IN THE MIDFACE (DISPLACEMENT OF THE 2 HALVES OF THE MAXILLA) W/ DEPOSITION AT THE MIDLINE SUTURE
MAXILLARY GROWTH CEASES @
AGE 15 IN FEMALES
AGE 17 IN MALES

Question 5

ANTEROPOSTERIOR GROWTH OF THE MAXILLA

Answer 5

DEPOSITION OF BONE POSTERIORLY AT THE MAXILLARY TUBEROSITIES
ANTERIOR DISPLACEMENT OCCURS AS BONE IS LAID DOWN AT THE POSTERIOR ASPECT
DOWNWARD GROWTH OCCURS BY…
DEVELOPMENT OF THE ALVEOLAR PROCESS, DENTAL ERUPTION, AND INFERIOR DRIFT OF THE HARD PALATE

Question 6

DISPLACEMENT PROCESSES OF THE MAXILLA

Answer 6

PRIMARY - ACTIVE DOWNWARD AND FORWARD GROWTH, MAXILLARY TUBEROCITY LENGTHENING POSTERIORLY
SECONDARY - PASSIVE DOWNWARD AND FORWARD GROWTH, MIDDLE CRANIAL FOSSA GROWS ANTERIORLY

Question 7

AGE CHANGES IN THE MAXILLA

Answer 7

BIRTH - TRANSVERSE AND ANTEROPOSTERIOR DIAMETERS ARE EACH GREATER THAN THE VERTICAL DIAMETER
ADULT - VERTICAL DIAMETER IS THE GREATEST (CONTROVERSIAL)
OLD AGE - REVERSION WITHIN LIMITS TO INFANTILE CONDITION - MAXILLARY HEIGHT IS DIMINISHED, W/ A LOSS OF TEETH => ALVEOLAR HEIGHT IS ABSORBED AND LOWER PART OF BONE IS CONTRACTED AND REDUCED IN THICKNESS

Question 8

ORTHODONTICS

Answer 8

MOVEMENT OF TEETH AND ALVEOLAR BONE MANIPULATION

CONSISTS OF DENTOFACIAL ORTHOPEDICS - MODIFICATION OF FACIAL GROWTH

Question 9

PRESSURE ON A TOOTH

Answer 9

WHEN APPLIED IT IS TRANSMITTED THROUGH THE PDL TO SURROUNDING BONE WHICH REMODELS IN SUCH A MANNER THAT THE SOCKET MIGRATES CARRYING THE TOOTH WITH IT

Question 10

COMPONENTS OF TOOTH MOVEMENT

Answer 10

1. ) COLLAGENOUS FIBERS - ACT AS SHOCK ABSORBERS (I.E. (a) ALVEOLAR CREST FIBERS, (b) HORIZONTAL FIBERS, (c) INTERRADICULAR FIBERS, (d) OBLIQUE FIBERS, (e) APICAL FIBERS)
2. ) CELLULAR ELEMENTS - VASCULAR, NEURAL, AND MESENCHYMAL
3. ) TISSUE FLUIDS (GCF) - ENZYMATIC/NON-ENZYMATIC

Question 11

SHARPEY’S FIBERS

Answer 11

TERMINAL ENDS OF PRINCIPAL PDL FIBERS

INSERT INTO TOOTH CEMENTUM AND PERIOSTEUM OF ALVEOLAR BONE

Question 12

DENTAL ANKYLOSIS

Answer 12

RARE DISORDER CHARACTERIZED BY FUSION OF TOOTH TO THE BONE PREVENTING ERUPTION AND ORTHODONTIC MOVEMENT
PDL IS OBLITERATED BY A BONY BRIDGE AND THE ROOT IS FUSED TO THE ALVEOLAR BONE

Question 13

REQUIREMENTS FOR TOOTH MOVEMENT

Answer 13

1. ) STIMULUS - BIOELECTRIC THEORY/PRESSURE TENSION THEORY

2. ) CELL DIFFERENTIATION (I.E. OSTEOBLASTS AND OSTEOCLASTS)

Question 14

BIOELECTRIC THEORY

Answer 14

CRYSTAL DEFORMATION - ELECTRONS MIGRATE DUE TO DISTORTION OF CROSS-LINKAGES BETWEEN COLLAGEN FIBERS IN THE BONE
ELECTRIC CHARGE IN SOLIDS GENERATED IN RESPONSE TO MECHANICAL STRESS
ELECTROPOSITIVE RESPONSE => RESORPTION
ELECTRONEGATIVE RESPONSE => DEPOSITION

Question 15

PRESSURE-TENSION THEORY

Answer 15

CHEMICAL SIGNALING
ALTERATION IN BLOOD FLOW FROM PRESSURE IN THE PDL
FORMATION AND RELEASE OF CHEMICAL MESSENGERS
ACTIVATION OF CELLS
PRESSURE - RESORPTION SIDE
TENSION - DEPOSITION SIDE (APPOSITION SIDE)

Question 16

TYPES OF ORTHODONTIC MOVEMENT

Answer 16

1. ) TIPPING - ONLY 1/2 PDL LOADED, FORCES MUST BE LIGHT (<50GM)
2. ) TRANSLATION - CROWN/ROOT MOVE CONCURRENTLY, WHOLE PDL LOADED, MORE FORCE REQUIRED (~70-100GM)
3. ) INTRUSION - ONLY APEX PDL LOADED, FORCES MUST BE VERY LIGHT (10-20GM)
4. ) EXTRUSION

Question 17

CELLULAR DETERMINANTS OF TOOTH MOVEMENT

Answer 17

FIBROBLASTS - COLLAGEN AND MATRIX MATERIAL
OSTEOBLASTS/CLASTS - REMODELING OF ALVEOLAR SOCKET
MESENCHYMAL PROGENITORS - GIVE RISE TO OSTEOBLASTS AND CHONDROCYTES

Question 18

MECHANISM OF OSTEOBLAST AND CHONDROCYTE AROUSAL FROM MESENCHYMAL PROGENITOR CELLS

Answer 18

RUNX2 - BINDS ENHANCERS AND/OR PROMOTERS FOR OSTEOCALCIN, OSTEOPONTIN, BONE SIALOPROTEIN, ALPHA (1) COLLAGEN, IL-3 ET AL. GENES, POI INHIBITS KAT6BETA-DEPENDENT TRANSCRIPTIONAL FACTORS
OSX - KNOCKOUT (-/-) CAUSES CHONDROCYTE DIFFERENTIATION OF RUNX2+ CELLS

Question 19

SIGNALING PATHWAYS FOR OSTEOBLAST DIFFERENTIATION

Answer 19

1. ) HEDGEHOG SIGNALING - REQUIRED FOR OSTEOBLAST DIFFERENTIATION THROUGH ENDOCHONDRAL OSSIFICATION
2. ) NOTCH SIGNALING - INHIBITS OSTEOBLAST DIFFERENTIATION
3. ) WNT SIGNALING - PROMOTES OSTEOBLAST DIFFERENTIATION (WNT PROTEINS BIND RECEPTORS)
4. ) BMP SIGNALING - PROMOTES TRANSITION TO RUNX2 OSX CELLS
5. ) FGF SIGNALING - REGULATES PREOSTEOBLAST PROLIFERATION, OSTEOBLAST DIFFERENTIATION AND MATURE OSTEOBLAST FUNCTION

Question 20

WNT SIGNALING

Answer 20

PROMOTES OSTEOBLAST DIFFERENTIATION (WNT-PROTEIN BINDS RECEPTORS (FRIZZLED OR LRP5 OR 6)
PROCEEDS DOWN EITHER B-CATENIN DEPENDENT OR INDEPENDENT PATHWAY
DEPENDENT - B-CATENIN STABILIZED AND PROMOTES TRANSCRIPTION OF TARGET GENES FOR TRANSITION TO MATURE OSTEOBLASTS
INDEPENDENT - ACTS THROUGH PROTEIN KINASE C-DELTA FOR OSTEOBLAST TRANSITION

Question 21

M-CSF

Answer 21

(MACROPHAGE COLONY STIMULATING FACTOR)
MADE AND SECRETED BY OSTEOBLASTS
CYTOKINE THAT INFLUENCES HEMATOPOIETIC STEM CELLS TO DIFFERENTIATE INTO MACROPHAGES OR OSTEOCLASTS (-> INCREASED BLOOD CALCIUM LEVELS)
PROMOTES SURVIVAL, PROLIFERATION AND DIFFERENTIATION OF OSTEOCLASTS
BINDS TO CSF-1

Question 22

SIGNALING PATHWAYS GOALS

Answer 22

PRIMARY GOAL - TO ASSEMBLE A TRANSCRIPTION COMPLEX ON THE CHROMATIN OF THE DNA (3 ELEMENTS)
(1) NFATc1
(2) AP-1
(3) NFkB
TOGETHER, THEY TURN ON GENES NEEDED FOR ACTIVATION AND DIFFERENTIATION OF OSTEOCLASTS

Question 23

OSTEOCLAST FORMATION/ACTIVATION (3 SIGNALS)

Answer 23

(1) CALCIUM - CALMODULIN NETWORK
(2) RANK/RANKL SIGNALING
(3) M-CSF