Anatomical Difference or Primary Dentition Flashcards

1
Q

Describe the basics of the primary dentition

A
  • 20 primary teeth
  • Incisors (A B), canines (C) and molars (D E)
  • No premolars
  • Primary molars replaced by premolars
  • Secondary molars erupt distal to primary E’s
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2
Q

Describe primary molar occlusion

A
  • Each tooth occlude with 2 teeth in opposing jaw
  • Mand. E larger than max. E so MB cusps of max and mand E may be in:
    Class I relationship with distal surfaces flush (75%)
    Distal surface of max E projects slightly over distal
    portion of mand E (25%)
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3
Q

Describe the general occlusion of the primary dentition

A
  • Maxillary arch larger
  • Primary teeth more upright
  • Mandibular incisors occlude with palatal surface of maxillary incisors
  • Anthropoid space (distal to mandibular C and mesial to maxillary C)
  • Teeth frequently worn
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4
Q

Describe the eruption pattern of primary dentition

A
  • Mandibular teeth erupt first in symmetrical pattern
  • Sequence more important than timing
  • All primary teeth erupt by age 20-30 months
  • Incisors, D’s, C’s, E’s
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5
Q

Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for lower primary A

A

HT - 13-16 weeks after ovulation
CF - 2.5 months after birth
BE - 6-10 months after birth
RF - 33 months after birth

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6
Q

Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for lower primary B

A

HT - 14-16 weeks after ovulation
CF - 3 months after birth
BE - 10-16 months after birth
RF - 30 months after birth

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7
Q

Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for lower primary C

A

HT - 16-18 weeks after ovulation
CF - 8-9 months after birth
BE - 17-23 months after birth
RF - 43 months after birth

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8
Q

Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for lower primary D

A

HT - 14-17 weeks after ovulation
CF - 5-6 months after birth
BE - 14-18 months after birth
RF - 34 months after birth

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9
Q

Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for lower primary E

A

HT - 17-19 weeks after ovulation
CF - 8-11 months after birth
BE - 23-31 months after birth
RF - 42 months after birth

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10
Q

Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for upper primary A

A

HT - 13-16 weeks after ovulation
CF - 1.5 months after birth
BE - 8-12 months after birth
RF - 33 months after birth

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11
Q

Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for upper primary B

A

HT - 14-16 weeks after ovulation
CF - 2.5 months after birth
BE - 9-13 months after birth
RF - 33 months after birth

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12
Q

Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for upper primary C

A

HT - 15-18 weeks after ovulation
CF - 9 months after birth
BE - 16-22 months after birth
RF - 43 months after birth

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13
Q

Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for upper primary D

A

HT - 14-17 weeks after ovulation
CF - 6 months after birth
BE - 13-19 months after birth
RF - 37 months after birth

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14
Q

Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for upper primary E

A

HT - 16-23 weeks after ovulation
CF - 11 months after birth
BE - 25-33 months after birth
RF - 47 months after birth

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15
Q

Name 3 types of unusual eruption patterns of primary teeth

A
  1. Natal teeth (present at birth)
  2. Neonatal teeth (present within 30 days)
  3. Late eruption (missing teeth)
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16
Q

What is most common site for natal / neonatal teeth?

A
  • Often lower incisor region

- Not usually supernumerary

17
Q

Describe the aetiology of natal / neonatal teeth

A
  • Unknown aetiology
  • Possible superficial position of tooth germ
  • Evidence of genetic contribution
18
Q

Describe the clinical appearance of natal / neonatal teeth

A
  • Normal appearance
  • Crown small, conical and poorly developed with yellowish hypoplastic enamel and dentine
  • Poor or failure of root development
19
Q

Describe the clinical symptoms and complications of natal / neonatal teeth

A
  • Possible pain or mobility of tooth
  • Trauma to mother’s breast
  • Drooling / Malaise
  • Risk of swallowing or aspiration
20
Q

Describe the management of natal / neonatal teeth

A
  • If no problems present, leave in place and reassure
  • If ulceration, smooth sharp edges or extract
  • Problems present then extract
21
Q

Name 4 differences between the anatomy of the crown of primary and secondary teeth

A
  1. Smaller and whiter
  2. Thinner enamel and dentine layers
  3. Enamel rods slope occlusally in cervical area
  4. Cervical area significantly constricted
22
Q

Name 2 differences between the anatomy of the pulp of primary and secondary dentition

A
  1. Large pulp horns closer to the outer surface

2. More tortuous and irregular pulp canals

23
Q

Name a difference between the anatomy of the roots of primary and secondary teeth

A

Roots flare as they approach the apex

24
Q

Describe the crowns of primary incisors

A
  • Shorter
  • Marked constriction at cervical margin
  • Rarely have memellons
25
Q

Describe the anatomy of the primary canines

A
  • Large crown
  • Bulge at cervical constriction
  • Symmetrical cone shape or mesial cone shape
  • Distal slope longer than mesial
26
Q

Describe the anatomy of the primary molars teeth

A
  • Marked cervical constrictions and buccal bulge
  • D has 4 cusps
  • E has similar fissure pattern to 6s
  • Broad contact areas with narrow occlusal tables
  • Roots are long and slender but divergent
27
Q

Describe the contact points of primary molars

A
  • Broad contact points in primary dentition
  • Differs from point contact in secondary teeth
  • Early diagnosis of interproximal caries may be difficult
28
Q

Describe the occlusion between primary molars

A
  • Incisor relationship edge to edge
  • Distal surfaces of upper and lower E’s are on same vertical plane
  • Upper E’s are longer than lower E’s
29
Q

Describe the innervation of deciduous teeth

A
  • Pattern of innervation shows some similarities to permanent dentition
  • Nerves pass from root to coronal area where they branch
  • Profuseness of nerve branching evident in pulp horn
  • High density of dentinal innervation in the cervical region
30
Q

Describe caries diagnosis and treatment for caries in primary dentition

A
  • Aim to prevent decay
  • If decay occurs aim to diagnose and treat early
  • Early diagnosis allows treatment with dietary modification, fissure sealant, ART and small restorations
  • Late diagnosis means pain and infection for child and treatment with pulpectomy and SS crowns or extractions
  • Late diagnosis often required general anaesthetic
31
Q

What are the implications of primary teeth anatomy in an examination

A
  • Unable to view interproximal surface
  • Clinical exam alone underestimate presence of caries
  • Need bitewings for examinations
  • Marginal ridge breakdown
32
Q

What are the implications of primary anatomy of teeth on investigations

A
  • Bitewings essential

- Caries > 2/3 into dentine which leads to pulpal inflammation

33
Q

Describe the implications of treatment in class II cavities

A
  • Decay spreads buccolingually
  • Wide, narrow class II preparation poor retention and high failure rate
  • SS crowns required in wide class II cavities
34
Q

What is late diagnosis treatment?

A
  • Reversible pulpitis / deep decay better pulpal success rate with SCC than filling
  • Pulpectomy and SCC lower success rate than secondary tooth and longer treatment for child
  • Extraction of primary molar in young child