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
