Paediatric tooth morphology Flashcards
What are the quadrants of primary dentition
5 (UR), 6(UL), 7(LL), 8(LR)
What does contra lateral tooth mean
Teeth of the same series
ex. upper right canine with upper left canine
What is the difference between primary and permanent dentition
The primary incisors are smaller in both their crown and root proportions
The primary molars are wider mesiodistally than the permanent premolars which take there place.
Primary molars crowns are more bulbous
The primary teeth are usually whiter in colour due to enamel being thinner
What are gingival cysts
Small collections of keratin white appear as white spots in gingiva. Not a concern for dentists just useful to recognise
What is congenital epulis
A growth in the mucosa. (benign tumour of oral cavity) Not concerning im children unless interfeering with feeding
What are natal or neonatal teeth
Teeth present before or shortly after birth. Usually the primary incisors developed in an ectopic position. Only removed when threatening airway (not attached so could fall out) or giving problems with feeding in which case they might be smoothed down
What does an eruption cyst appear like
Small fluid fild sac within the gum. Sometimes blue colour due to blood within the folicle. These often resolve naturally
When do teeth start forming
During week 5 of intra-uterine life (IUL)
When does hard tissue formation of primary teeth begin
Week 13 of intra-uterine life
When would the root formation of a maxillary central incisor be completed
When a child is around 33 months (3 years)
When is the crown of maxillary second primary molars (55 65) completed
At 11 months after birth
when do the primary second molars usually erupt
Bewteen 25-33 months
When are the second primary molar roots fully formed
By around 47 months
What often causes defects in primary dentition
Systemic disturbances during calcifiction (complicated pregnancy or problems at birth)
How much of the crowns of each tooth are calcified by birth
½ of central incisors
¹/3 of lateral incisors
Tip of primary canines
½ of first primary molars
¹/3 of second primary molars
Tip of cusps of first permanent molars
What causes tooth eruption
The exactbiology has not been explained but 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 some possible theories behind tooth eruption
Cellular proliferation at the apex of the tooth
Localized change in blood pressure/hydrostatic pressure
Metabolic activity within the PDL
Resorption of the overlying hard tissue
What role does the dental follicle play in tooth eruption
Follicle is activated to initiate osteoclastic activity in the alveolar bone ahead of the tooth and clear a path for tooth eruption (unsure what signals this)
Once a path for tooth eruption is acheived what is the role of osteoclasts
There is no osteoclastic activity once the path is cleared
When does tooth eruption stop
When the tooth comes into contact with something (i.e opposing arch)
-Continues throughout life to compensate for vertical growth of the jaws and tooth wear
When is primary dentition usually complete
2.5/3 years
What tooth has a prominent mesiobuccal tubercle
Upper first primary molar (D or 4)
Which tooth has a transverse ridge
Upper right second molars (E or 55)
Which primary tooth has 3 buccal cusps
Lower right second primary molar (E or 85)
Why do primary teeth roots tend to flare and flatten
To allow room in between for the developing permanent tooth crowns
What are the differences of the hard tissue in primary and permanent teeth
Coronal dentine is much thinner in primary teeth along with the enamel with has a consistent thinner depth of primary teeth and doesnt vary
What is anthropoid or primate spacing
Spacing mesial to upper deciduous canine
(52 —> 53)
Spacing distal to lower deciduous canine.
(73 —–> 74)
What is the usual leeway space caused by the primary molars
Usually 1.5 mm per side upper and 2.5 mm per side lower
When does mixed dentition begin
When the first permanent tooth erupts and ends when the last primary tooth is exfoliated (6-11 years)
What is often the last tooth to erupt
Permanent canine
What is often the last primary tooth to fall out
Primary upper canine
What is the eruption sequence of permanent teeth
UPPER:
6,1,2,4,5,3,7,8
LOWER:
6,1,2,3,4,5,6,7,8
How long does it take for a permanent root to complete apexogenesis from eruption
3 years (1.5 in primary)
