Oral Cavity Flashcards Preview

BDS 1 > Oral Cavity > Flashcards

Flashcards in Oral Cavity Deck (310)
Loading flashcards...
91

What are cusps of Carabelli?

Extra cusp on palatial surface of palatal cusp on upper molars

92

What are the main distinguishing factors between deciduous and permanent dentition?

5 teeth in each quadrant vs 8
ABCs markedly smaller than permanent 123s
DEs larger than 45s that replace them
Deciduous crows more bulbous
Deciduous less mineralised; crown more susceptible to wear
Roots smaller, thinner; D, Es divergent allowing space for premolars to grow

93

Which deciduous teeth have 1 root?

ABCs

94

Which deciduous teeth have 2 roots?

L: DEs

95

Which deciduous teeth have 3 roots?

U: DEs

96

What are the main differences between permanent and deciduous teeth?

Number: 20vs32
Size: smaller, narrower, shorter
Structure: thinner enamel
Crown shape: molars less complex
Root shape: robust, spindly, divergent
Pulp size, shape: relatively larger, prominent horns

97

What are the 4 theories of tooth eruption?

1. Root growth
2. Bone remodelling
3. Dental follicle
4. Periodontal ligament

98

What are the 4 processes of tooth development and eruption?

1. Pre-eruptive movement
2. Intra-issues, tooth in alveolar bone
3. Mucosal penetration: clinical emergence
4. Post-occlusal movement: passive eruption

99

What are the 4 stages of dentition?

1. Edentulous: before any teeth erupted
2. Deciduous: 6m-5y
3. Mixed: 6-12y
4. Permanent: 12y+

100

Outline the timeline of deciduous eruption

6-12m: LABs, UABs
14m: Ds
18m: Cs
24m: Es

101

Outline the timeline of permanent dentition

Phase 1: 6-8y: [16] 2
Phase 2: 10-12y: [467] 3
Phase 3: 17-20y+: 8

102

What are the 2 stages of tooth development?

1. Tissue differentiation
2. Hard tissue formation: enamel, cementum, dentine

103

What is the tooth germ derived from?

ectodermal mesenchyme
Dental lamina grows down from oral epithelium and grows bud which gives rise to tooth germ - each develops a tooth

104

What are the 3 sections of the tooth germ?

1. Enamel organ
2. Dental papilla
3. Dental follicle

105

Where is the enamel organ derived from and what does it differentiate to?

Derived from ectodermal oral epithelium
Tissue differentiates to ameloblasts - secretes enamel, dictates shape of crown

106

Where is dental papilla derived from and what does it differentiate to?

Derived from mesenchyme neural crest cells
Tissue differentiates into odontoblasts and develops into pulp

107

Where is the dental follicle derived from and what does it differentiate into?

Derived from mesenchyme neural crest cells
Differentiates into cementoblasts, osteoblasts, fibroblasts

108

What are the 6 stages of tooth development and when do they occur?

1. Initiation: 6/7w
2. Bud: 8w
3. Cap: 9/10w
4. Bell: 11/12w
5. Apposition: m-yrs
6. Maturation: m-yrs

109

What happens in the bud stage?

Mesenchyme condenses around ectodermal bud from oral epithelium

110

What happens in cap stage?

Enamel organ forms 'cap' above dental papilla

111

What 3 things happen in bell stage?

1. Enamel organ folds into shape of crown
2. Differentiation of enamel organ tissue (pre-ameloblasts) and dental papilla tissue (odontoblasts) begins at cusp tip
3. Dentine secretion by odontoblasts stimulates ameloblasts

112

What happens in the appositional stage?

Hard tissues secreted as partially calcified matrix starting at cusp tip
Crown: mineralised crown tissue deposition first
Root: after crown formation, roots grow, tooth erupts

113

What happens in maturation stage?

Mineralisation completes, enamel matures
Ameloblasts die, odontoblasts line pulp

114

What is the alveolar bone?

Part of the maxilla/mandible that supports and protects teeth

115

What is the boundary of the alveolar bone?

Arbitrary but apices of roots

116

Describe the morphology of the alveolar bone

Finer towards margins (ventral and dorsal), thickest at apices
Dense facial and lingual cortical plates: thinnest at mandibular incisors, thickest at mandibular molars
Maxilla: thicker P>B
Mandible: 1-5 thicker L>B, 6-8 thicker B>L
Radiographically: radio opaque line (lamina dura) lining alveolar socket

117

What are the 4 functions of the alveolar bone?

1. Distribute and absorb forces (mastication)
2. Serve as attachment site for tooth apparatus: PDL, muscles
3. Framework for bone marrow
4. Ion reservoir

118

What does the biological property of plasticity allow the alveolar bone to do?

Remodel according to functional demand

119

What is the possible damage when doing extractions regarding the alveolar bone?

At thinnest parts (mandibular incisor) remove alveolar bone w/ tooth

120

What is the dependency of the alveolar bone?

Dependent on tooth
Following extraction will atrophy