Primary Tooth Morphology Flashcards
What are early problems babies can have prior to teeth eruption? (4 points)
- Gingival Cysts (Epstein’s P e arls/Bohns nodules)
- Congenital Epulis
- Natal or neonatal teeth
- Eruption cysts
How would you treat gingival cysts?
- Do not need to do anything to them - they will resolve
What are Bohn’s nodules?
- Tiny multiple cysts in new-borns. They are found at the junction of the hard and soft palates and along buccal and lingual parts of the dental ridges and are derived from epithelial remnants of mucous gland tissue
What are Epstein pearls?
Small white or yellow cystic vesicles often seen in the medial palatal raphe of the mouth of newborn infants. They are typically seen on the roof of the mouth and are filled with fluid. They are caused by entrapped epithelium during the development of the palate
What is a congenital epulis?
- A proliferation of cells on the jaw at birth. This is more commonly found in female babies. The cause of this type of epulis is unknown
What is a natal tooth?
- Tooth there when the baby is born
What is a neonatal tooth?
- Tooth erupted just after the baby if born
Are natal/neonatal teeth extra teeth?
- No, they have just been in an ectopic position
What is an ectopic position?
- An abnormal position/location
What is an eruption cyst?
Where tooth is erupting and blood has gotten into the follicle space
- Don’t need to do anything about them - they will resolve themselves
What number would you use for an upper right deciduous tooth?
5
What number would you use for an upper left deciduous tooth?
6
What number would you use for an lower right deciduous tooth?
8
What number would you use for a lower left deciduous tooth?
7
In which week of intra-uterine life do teeth start to form?
- Week 5
In which week of intra-uterine life does hard tissue formation start and can be detected on subsequent ultrasound scans?
- Week 13
At how many weeks I.U.L does the hard tissue formation begin for the deciduous maxillary central incisor?
13-16
At how many weeks I.U.L does the hard tissue formation begin for the deciduous mandibular central incisor?
13-16 weeks
At how many weeks I.U.L does the hard tissue formation begin for the deciduous maxillary lateral incisor?
14.7-16.5 weeks
At how many weeks I.U.L does the hard tissue formation begin for the deciduous mandibular lateral incisor?
14.7-16.5 weeks
At how many weeks I.U.L does the hard tissue formation begin for the deciduous maxillary canine?
15-18 weeks
At how many weeks I.U.L does the hard tissue formation begin for the deciduous mandibular canine?
16-18 weeks
At how many weeks I.U.L does the hard tissue formation begin for the deciduous maxillary first molar?
14.5-17 weeks
At how many weeks I.U.L does the hard tissue formation begin for the deciduous mandibular first molar?
14.5-17 weeks
At how many weeks I.U.L does the hard tissue formation begin for the deciduous maxillary second molar?
16-23.5 weeks
At how many weeks I.U.L does the hard tissue formation begin for the deciduous mandibular second molar?
- 17-19.5 weeks
What can systemic disturbances during calcification lead to?
- Can lead to defects in the enamel which was forming at the time
- Defects in the primary dentition (which are not hereditary) are most likely the result of a difficult pregnancy for the mother or complications at birth
How much of the crown of central incisors are present at birth?
1/2
How much of the crown of lateral incisors are present at birth?
1/3
How much of the crown of primary canines are present at birth?
- Just the tip
How much of the crown of first primary molars are present at birth?
1/2
How much of the crown of second primary molars are present at birth?
1/3
How much of the crown of first permanent molars are present at birth?
- The tip of the cusps
The exact biology of tooth eruption has not been explained by any one theory. It is likely that it is a multifactorial process. What needs to happen for tooth eruption to occur?
- A force must be generated to propel the tooth through the bone and gingival tissue. In the case of the permanent dentition the primary tooth root must also be removed in some cases
What are the possible theories behind tooth eruption? (4 points)
- Cellular proliferation at the apex of the tooth
- Localised change in blood pressure/hydrostatic pressure
- Metabolic pressure within the PDL
- Resorption of the overlying hard tissue and apoptosis
How does resorption of the overlying hard tissue occur?
- Due to enzymes in the dental follicle
- Dental follicle best seen on radiograph as a dark halo round the unerupted tooth
Is remodelling of bone or primary tooth tissue essential to the process of tooth eruption?
- Yes
- BUT animal studies have shown that the resorption process can be uncoupled from the eruption process i.e. it is not necessary for the tooth to erupt to cause resorption of the bone
The follicle has been shown to play an essential role in active tooth eruption. What is the follicle activated to initiate?
- Initiates osteoclastic activity in the alveolar bone a head of the tooth and clear a path for tooth eruption
- Once the crestal bone has been beached (and just have soft tissues ahead) the follicle is likely to play a lesser role
Theories regarding which 3 things have been discounted as major factors for tooth eruption?
- Root elongation
- Periodontal ligament
- Local changes in vascular pressure