Anatomical Difference or Primary Dentition Flashcards
Describe the basics of the primary dentition
- 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
Describe primary molar occlusion
- 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%)
Describe the general occlusion of the primary dentition
- 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
Describe the eruption pattern of primary dentition
- 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
Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for lower primary A
HT - 13-16 weeks after ovulation
CF - 2.5 months after birth
BE - 6-10 months after birth
RF - 33 months after birth
Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for lower primary B
HT - 14-16 weeks after ovulation
CF - 3 months after birth
BE - 10-16 months after birth
RF - 30 months after birth
Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for lower primary C
HT - 16-18 weeks after ovulation
CF - 8-9 months after birth
BE - 17-23 months after birth
RF - 43 months after birth
Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for lower primary D
HT - 14-17 weeks after ovulation
CF - 5-6 months after birth
BE - 14-18 months after birth
RF - 34 months after birth
Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for lower primary E
HT - 17-19 weeks after ovulation
CF - 8-11 months after birth
BE - 23-31 months after birth
RF - 42 months after birth
Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for upper primary A
HT - 13-16 weeks after ovulation
CF - 1.5 months after birth
BE - 8-12 months after birth
RF - 33 months after birth
Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for upper primary B
HT - 14-16 weeks after ovulation
CF - 2.5 months after birth
BE - 9-13 months after birth
RF - 33 months after birth
Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for upper primary C
HT - 15-18 weeks after ovulation
CF - 9 months after birth
BE - 16-22 months after birth
RF - 43 months after birth
Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for upper primary D
HT - 14-17 weeks after ovulation
CF - 6 months after birth
BE - 13-19 months after birth
RF - 37 months after birth
Describe the hard tissue formation, crown formation, beginning of eruption and completion of root formation for upper primary E
HT - 16-23 weeks after ovulation
CF - 11 months after birth
BE - 25-33 months after birth
RF - 47 months after birth
Name 3 types of unusual eruption patterns of primary teeth
- Natal teeth (present at birth)
- Neonatal teeth (present within 30 days)
- Late eruption (missing teeth)
What is most common site for natal / neonatal teeth?
- Often lower incisor region
- Not usually supernumerary
Describe the aetiology of natal / neonatal teeth
- Unknown aetiology
- Possible superficial position of tooth germ
- Evidence of genetic contribution
Describe the clinical appearance of natal / neonatal teeth
- Normal appearance
- Crown small, conical and poorly developed with yellowish hypoplastic enamel and dentine
- Poor or failure of root development
Describe the clinical symptoms and complications of natal / neonatal teeth
- Possible pain or mobility of tooth
- Trauma to mother’s breast
- Drooling / Malaise
- Risk of swallowing or aspiration
Describe the management of natal / neonatal teeth
- If no problems present, leave in place and reassure
- If ulceration, smooth sharp edges or extract
- Problems present then extract
Name 4 differences between the anatomy of the crown of primary and secondary teeth
- Smaller and whiter
- Thinner enamel and dentine layers
- Enamel rods slope occlusally in cervical area
- Cervical area significantly constricted
Name 2 differences between the anatomy of the pulp of primary and secondary dentition
- Large pulp horns closer to the outer surface
2. More tortuous and irregular pulp canals
Name a difference between the anatomy of the roots of primary and secondary teeth
Roots flare as they approach the apex
Describe the crowns of primary incisors
- Shorter
- Marked constriction at cervical margin
- Rarely have memellons
Describe the anatomy of the primary canines
- Large crown
- Bulge at cervical constriction
- Symmetrical cone shape or mesial cone shape
- Distal slope longer than mesial
Describe the anatomy of the primary molars teeth
- 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
Describe the contact points of primary molars
- Broad contact points in primary dentition
- Differs from point contact in secondary teeth
- Early diagnosis of interproximal caries may be difficult
Describe the occlusion between primary molars
- 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
Describe the innervation of deciduous teeth
- 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
Describe caries diagnosis and treatment for caries in primary dentition
- 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
What are the implications of primary teeth anatomy in an examination
- Unable to view interproximal surface
- Clinical exam alone underestimate presence of caries
- Need bitewings for examinations
- Marginal ridge breakdown
What are the implications of primary anatomy of teeth on investigations
- Bitewings essential
- Caries > 2/3 into dentine which leads to pulpal inflammation
Describe the implications of treatment in class II cavities
- Decay spreads buccolingually
- Wide, narrow class II preparation poor retention and high failure rate
- SS crowns required in wide class II cavities
What is late diagnosis treatment?
- 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
