Growth And Development-Orthodontics Colloquim

Question 1

Cellular level growth mechanisms

Answer 1

🔹Hypertrophy
🔹Hyperplasia
🔹Secretion of extracellular material

Question 2

Hypertrophy

Answer 2

Increase in size of cells

Question 3

Hyperplasia

Answer 3

Increase in number of cells

Question 4

Secretion of extracellular material

Answer 4

Results in increase in size of organs regardless of no. and size of cells themselves

Question 5

Tissue types

Answer 5

🔹Soft tissue
🔹Hard tissue

Question 6

Growth mechanisms at soft tissue level

Answer 6

🔹Hyperplasia
🔹Hypertrophy

—> Interstitial growth

Question 7

Growth mechanisms at hard tissue level

Answer 7

🔹Hyperplasia
🔹Hypertrophy

—> interstitial growth

🔹Secretion of extracellular material—> mineralisation resulting in surface aposition of bone

Question 8

Locations of growth in bone

Answer 8

• Growth sites
• Growth centres

Question 9

Growth sites

Answer 9

• Location where bone enlarges and moves
• Stimulated or repressed by external factors

Examples. Sutures and periosteal tissue

Question 10

Growth centers

Answer 10

• Locations where independent growth occurs
• Genetically controlled

Examples. Cartilages

Question 11

Difference between growth sites and growth centers

Answer 11

Growth centers are are also growth sites but sites are not always growth centers

Question 12

Endochondral bone formation

Answer 12

• Cartilaginous precursor
• Ossification of cartilage into bone

Question 12

Bone formation types

Answer 12

• Endochondral bone formation
• Intramembranous bone formation

Question 13

Intramembranous bone formation

Answer 13

• Bone matrix(osteoid) secreted into connective tissue
• No intermediate cartilage

Question 14

Mechanisms of skeletal growth

Answer 14

• Remodelling
• Primary translation
• Secondary translation

Question 15

Remodelling

Answer 15

• Resorption and aposition of bone resulting in change to size and shape of bone
• Periosteal and endosteal cells

Question 16

Primary translation(displacement)

Answer 16

Bone remodelling results in position change in space

Question 17

Secondary translation

Answer 17

Displacement of entire bone due to expansion of adjacent structures

Question 18

Components of craniofacial region

Answer 18

1. Skull
   * Cranial vault
   * Cranial base
2. Facial skeleton
   * Nasomaxillary complex
   * Mandible

Question 19

Cranial vault and base functions

Answer 19

• Support and protect brain
• Passageway for nerves and blood vessels
• Connect spinal column, mandible and NMC

Question 20

Functions of nasomaxillary complex and mandible

Answer 20

• Mastication
• Respiration
• Speech

Question 21

Cranial vault type of growth

Answer 21

• Intramembranous ossification

Question 22

Cranial vault mechanism of growth

Answer 22

• Direct aposition of bone in sutures and frontanelles
• Surface remodelling-Aposition externally and resoption internally

Question 23

Role of frontanelles

Answer 23

Sites of growth for cranial vault

Question 24

Cranial base type of growth

Answer 24

* Endochondral ossification of several cartilages ## Footnote Frontal, Ethmoid, sphenoid, Occipital

Question 25

Mechanism of growth of Cranial base

Answer 25

* Endochondral ossification of synchondroses-->Connect bone segments * Surface remodeling(apposition externally and resorption internally)

Question 26

Synchondroses

Answer 26

Sites and centers of independent genetically controlled growth

Question 26

Nasomaxillary complex includes

Answer 26

Maxilla and nasal bones

Question 27

Type of growth in Nasomaxillary complex

Answer 27

Intramembranous ossification

Question 28

Mechanism of growth of Nasomaxillary complex

Answer 28

1. Direct apposition of bone in sutures * Growth of maxilla backward and upward 2. Surface remodelling 3. Primary displacement * NMC translated downward and forward 4. Secondary displacement * NMC displaced forward by cranial base 5. Nasal septum * Downward and forward growth

Question 29

3 Planes of maxillary growth

Answer 29

* Transversal * Sagittal * Vertical

Question 30

Mandible type of growth

Answer 30

1. Intramembranous ossification 2. Endochondral ossification ## Footnote 1. Mesenchymal tissue within mandibular process 2. Of condylar cartilage and symphysis-->upward and backward growth

Question 31

Mechanisms of growth of mandible

Answer 31

* Surface remodelling * Primary displacement(downward and forward) * Secondary displacement(downward and backward)