development of normal occlusions 1

Question 1

stage of gum pads:

Answer 1

from birth until completion of deciduous dentition (0-2 1/2 years)

Question 2

deciduous dentition :

Answer 2

2 1/2 to 6 years

Question 3

mixed dentition :

Answer 3

6 to 12 years

Question 4

maxillary gum pad and mandibular gum pad shape :

Answer 4

maxillary : horse shoe

mandibular: U

Question 5

alveolar part of maxillary gum pad is separated on its palatal side from hard palate by:

Answer 5

dental or gingival groove ( continuous horizontal groove)

Question 6

mandibular grooves are ____ in relation to maxillary

Answer 6

less defined

Question 7

groove distal to canine segment continuing on buccal side of the gum pad:

Answer 7

lateral sulcus

Question 8

which typr of growth in the first year of life allows gum pads to increase in arch width ?

Answer 8

lateral growth , which finally permits incisors to errupt with good alignment . this process is helped by molding effect of upper lip

Question 9

calcification of deciduous teeth begin ___

Answer 9

early in 4th month IUL

Question 10

What is the first tooth to erupt ?

Answer 10

mandibular central incisor at about 6-7 months

primary maxillary central : 8 months

both maxillary and mandibular lateral : 9 months

first deciduous molars: 14-15 months

canine : 18 months \

2nd molar: 24 months

Question 11

most primary arches are ___ in shape

Answer 11

ovoid

Question 12

what is the primate space?

Answer 12

additional spacing over the generalized spacing of the deciduous dentition found mesial to the maxillary canines and distal to the mandibular canines

Question 13

what is responsible for the closing of the mandibular primate space?

Answer 13

eruption of permanent mandibular first molar

Question 14

what is responsible for the closing of the maxillary primate space?

Answer 14

the eruption of the maxillary central incisor

Question 15

what sort of occlusion of the anterior teeth can be seen at around 3 years of age ?

Answer 15

excessive overbite . it is self correcting through :
-eruption of deciduous molars
-attrition of incisors
-forward movement of mandible as it catches up to maxillary growth

Question 16

slide 35??

Question 17

flush terminal plane of distal surfaces of both maxillary and mandibular second primary molars is due to

Answer 17

the mandibular 2nd primary molar being wider mesiodistally than the maxillary one

Question 18

what are the complications that may be present if the flush terminal plane remians ?

Answer 18

it will lead to an end to end relationship of the first permanent molars when they erupt distal to the second deciduous molars and arrive to occlusion

Question 19

in case of absence of spacing in deciduous dentition :

Answer 19

no space will be available for early mesial migration of mandibular first permanent molar. so the mandibular first permanent molar will remain in an end to end relationship till shedding of mandibular deciduos decond moalrs

Question 20

mesial step in deciduous dentation is important because it allows for

Answer 20

In such a case the distal surface of the mandibular primary second molar assumes a distinct mesial step terminally in relation to that of the maxillary allowing the first permanent molars to erupt in normal molar relationship.

Question 21

describe the processes of early mesial shift :

Answer 21

1.) closure of primate space distal to mandibular canine \

2.) As a result of natural occlusal wear of the cusps of the deciduous incisors, the mandible is allowed to move forward by its forward component of growth.

Question 22

causes resulting in distal step:

Answer 22

thumb sucking , excessive growth of maxilla

Question 23

accessional teeth+ non sucedaneous

Question 24

first transitional period of mixed dentition :

Answer 24

-eruption of permanent molaras and eruption / transition/ exchange of permanent incisors—> shifting of flush terminal plane

Question 25

second transitional period :

Answer 25

-replacement of deciduous molars and canine by permanent canine and premolars following 2 events : -leeway space of nance -ugly duckling stage

Question 26

how does the early mesial shift of the erupting first molar occur?

Answer 26

by utilizing normal physiological spaces between deciduous molars/ primate spaces

Question 27

mechanism of later mesial shift of erupting first molars:

Answer 27

leeway space of nance

Question 28

permanent incisors develop____ to primary incisors .

Answer 28

lingually , because they require more space since they are larger. this extra space required is known as the incisor liability

Question 29

size difference between maxillary primary and permanent incisors? between mandibular primary and permanent incisors=?

Answer 29

7mm 5mm

Question 30

incisor liability is provided by :

Answer 30

-spacing of deciduous incisors -increase in inter-canine width -change in inter-incisal inclination or angulation ( from 150 degrees (deciduous incisor ) to 123 degrees in the permanent incisor

Question 31

stable phase ( lasts for 1.5 years from 8-9.5 y) in which the maxillary and mandibular arches consist of sets of deciduoud and permanent teeth :

Answer 31

inter-transitional period

Question 32

second transitional period is from :

Answer 32

age 9-10. includes shedding of primary C,D,E till emergance of permanent 3,4,5,7 -usual sequence : maxilla: -4-3-5 or 4-5-3 :mandible: 3-4-5

Question 33

establishment of occlusion occurs in which stage ?

Answer 33

second transitional period

Question 34

how is the dental arch affected in second transitional period?

Answer 34

its length is reduced just prior to eruption of 2nd molar by mesial eruptive forces

Question 35

leeway space:

Answer 35

difference of mesiodistal thickness between primary canines , primary first and second molars and permanent canine , and premolars ( primary is less thick )

Question 36

leeway space of upper arch and of lower arch :

Answer 36

maxillary :0.9mm mandibular: 1.7 mm

Question 37

how is the leeway space utalized?

Answer 37

Some of this Leeway space is taken by the distal movement of the larger permanent canine falling into the primate space, while other part is utilized by the late mesial shift of the mandibular molars in order to establish a normal molar relationship.

Question 38

when does the ugly duckling stage occur?

Answer 38

8-9 years

Question 39

why does the ugly duckling stage occur?

Answer 39

erupting canines impinge on roots of lateral incisors causing them to flare and causing a mild diastema ( less than 3mm , no intervention required ) it is a self correcting anomaly