Mixed Dentition

Question 1

what are the dental arch measurements

Answer 1

-arch width
- arch perimeter
- intercanine distance

Question 2

how is arch length (depth) measured

Answer 2

at the midline to a tangent touching the distal surfaces of the second primary molars

Question 3

what are the arch length changes

Answer 3

• lose arch length in the lower arch: lower incisor eruption
• gain length in the upper arch : upper incisor eruption

Question 4

where is arch width measured from

Answer 4

• between the cusps of the canines in the transverse plane
• between the occlusal grooves of the second primary molars

Question 5

significant arch width changes from ______ in the ___ arch

Answer 5

primary to mixed; lower

Question 6

how is arch perimeter measured

Answer 6

from the distal surface of the second primary molar around the arch over the contact points and incisal edges in a smoothed curve

Question 7

when is the mixed dentition period

Answer 7

6-13 years old

Question 8

the permanent first molars erupt to the ____ of the primary dentition

Answer 8

distal

Question 9

describe primary root resorption-> permanent tooth eruption

Answer 9

• crown of the permanent tooth is formed
• the root develops and the primary tooth starts to resorb
• when the root is totally resorbed, the primary tooth exfoliates and the permanent tooth erupts
• the permanent tooth will stop erupting when it reaches the occlusal plane

Question 10

tooth replacement has variability in:

Answer 10

-sequence
- timing
- position
-numbers

Question 11

what is the occurrance of congenitally missing teeth

Answer 11

3-5% of population

Question 12

what are the most common congenitally missing teeth and which is the most common of all

Answer 12

• maxillary lateral incisor: most frequent
• mandibular second premolar
• maxillary central incisor

Question 13

missing primary tooth =

Answer 13

no permanent successor

Question 14

what is ankylosis

Answer 14

fusion of the root of a primary tooth to the underlying bone which stops the tooth from erupting

Question 15

what is ankylosis due to

Answer 15

localized defect during eruption process in periodontal ligament whereby osseous

Question 16

what is the result of ankylosis in mixed dentition

Answer 16

occlusal level of ankylosed tooth does not keep up with vertical level of adjacent teeth

Question 17

what is the treatment for ankylosis

Answer 17

• monitor these teeth - 50% will self correct
• if they fail to exfoliate- extract the tooth to avoid damaged to the permanent dentition

Question 18

describe the variability in mixed dentition

Answer 18

high