Etiology powerpoint

Question 1

what is emergence? occurs when? root formation present?

important for?

Answer 1

appearance through the alveolar mucosa membrane
• Occurs prior to completion of root
o Passage through alveolar crest = 2/3 complete
o Emergence through gingiva= ¾ complete
• Important for development of oral motor behavior & acquisition of masticator skills
• Nasmyth membrane aka primary enamel cuticle

Question 2

eruption

Answer 2

continuous movement from the dental bud to occlusion

Question 3

active eruption

Answer 3

is the movement of the tooth down out of the alveolar bone into position on the occlusal/incisal plane
o Once teeth hit occlusion (occlusal plane), active eruption ends

Question 4

passive eruption

Answer 4

continuing process of adaptation of tooth to changing incisal/occlusal relationships such as attrition & changing locations of adjacent and opposing teeth (tooth tipping, keep occlusal line)

Question 5

Neonatal skull

Answer 5

• Large brain case-neurocranium
• Smaller splanchonocranium
o Contains jaws and teeth, jaws assume initial shape at 6th week as embryo
o Mandibular arch larger than maxillary

Question 6

STAGES OF TOOTH FORMATION

Answer 6

bud (starting at 6th week fetal), cap, bell

Question 7

tooth formation: Dental lamina and bud stage

Answer 7

a. Epithelial thickening in region where teeth will form from Dental lamina
b. Tooth buds are round/oval shape and appear after dental lamina differentiation
c. Enamel organ is another name for tooth buds

Question 8

tooth formation: cap stage

Answer 8

a. Basal portion of round bud invaginates (makes concavity) thus starting cap stage
b. Presence of inner and outer epithelium
c. Oral epithelium now present

Question 9

tooth formation: bell stage

Answer 9

a. Concavity depends to form tooth’s crown marking the beginning of bell stage
b. Most of enamel and detin are laid down
c. Towards end of this stage, dental lamina connection with deciduous tooth disintegrates
i. Succedaneous tooth bud now forms
d. END of bell stage when CEJ is formed; start of primary root development

Question 10

bell stage ends when?

Answer 10

CEJ forms

Question 11

what disintegrats twoards end of bell stage?

Answer 11

dental lamina connection with deciduous tooth disintegrates

Question 12

Hertwigs’s sheath forms?

Answer 12

the root

Question 13

Epithelial Rests of Malassez (ERM)

Answer 13

o Clusters of residual cells from Hertwigs’s epithelial root sheath that DID NOT disappear
o Become part of periodontal ligament cells that are around the tooth
**believed to form cysts, calficied cememticles in liagment, cementum repair and regeneration

Question 14

Nasmyth membrane

Answer 14

allows the tooth to erupt without bleed; thin layer of tissue produced by ameloblast that covers the tooth when it is erupted and then worn off by chewing or brushing; primarily a basal lamina
o Also protects enamel from resorption by cells of dental sac
o Secrets desmolytic enzymes for elimination of the dental sac
o Allows for fusion between reduced enamel epithelium and oral epithelium (this is how it reduces bleeding)

Question 15

leeway space

Answer 15

space normally provided for the smaller premolar due to the sider primary molars

Question 16

primate space

Answer 16

space provided for the premolars due to the growth of the jawbones and wider primary molars

Question 17

Premature loss of primary teeth cause?

Answer 17

Insufficient spacing for adult dentition, loss of arch length, initiation and development of an abnormal occlusion

Question 18

Root resorption of primary teeth starts?

Answer 18

At least a year prior to exfoliation

Question 19

resoption

Answer 19

roots melt away starting at apex and moves towards cervix by osteoclasts activity