Chapter 9: Age Related Changes In The Dental Arch

Question 1

Changes in the Craniofacial complex:

Answer 1

• intercanine width
• bimolar width
• perimeter of the arch
• depth of the arch

Question 2

In the intercanine and bimolar width what plane changes?

Answer 2

Transverse

Question 3

The transverse diameter is higher in the?

Answer 3

Maxilla

Question 4

Eruptive path of canines and molars:

Answer 4

• divergent in maxilla
• convergent in mandible

Question 5

Middle palatine suture growth affects?

Answer 5

The transverse diameter

Question 6

When does the mandible symphysis close?

Answer 6

8 months

Question 7

The intercanine width is?

Answer 7

The distance between the cusp of the canine on one side and the cusp of the contralateral canine

Question 8

Where is the intercanine width measured?

Answer 8

• primary and permanent dentition
• upper and lower arches

Question 9

How do we measure the intercanine width if there is no cusp?

Answer 9

Worn facets

Question 10

Are there any changes observed in the maxilla of primary dentition regarding the intercanine width?

Answer 10

No

Question 11

When is the largest increase in intercanine width in the maxilla:

Answer 11

6-12 years old
- boys: +5mm
- girls:+4mm

Question 12

The largest increase in the intercanine width in the maxilla is due to?

Answer 12

The eruption of the permanent lateral incisors and the canines

Question 13

Intercanine width in the maxilla, chronologically:
Ages:
2-6:
6-10:
10-12:
12-16:
16:

Answer 13

2-6: no changes, no increase
6-10: increase caused by the eruption of the central and lateral incisors
10-12: increase caused by the eruption of the canine
12-16: stable period
16: small decrease in width could occur by mesialisation in the arch

Question 14

Intercanine width in the mandible, increases from which ages?

Answer 14

2-18 years old
Boys: +3mm
Girls: +2.5mm

Question 15

Increase in intercanine width is always higher in ?

Answer 15

Boys

Question 16

Intercanine width in the mandible, when is there a slight decrease?

Answer 16

From 11-12 years old, after the eruption of the 2nd permanent molar

Question 17

Intercanine width in the mandible, increases with?

Answer 17

The eruption of the lateral incisors, exfoliation of the primary canines and eruption of the permanent canines

Question 18

Intercanine width in the mandible: growth by?

Answer 18

Lateral bone apposition in the body of the mandible

Question 19

Bimolar width: how is it calculated in permanent dentition?

Answer 19

By measuring the distance between the mesial-buccal cusp of the 1st permanent molar and its contralateral counterpart

Question 20

Bimolar width: how is it calculated in primary dentition?

Answer 20

The distance between the mesial-buccal cusp of the 2nd temporary molars

Question 21

Bimolar width: increase in the maxilla is due to?

Answer 21

The eruption of the 1st permanent molars (divergent eruption of the maxillary molars)

Question 22

Bimolar width: is there an increase in the mandible?

Answer 22

No

Question 23

Bimolar width: in the posterior area of the mandible and maxilla, what shape of growth is there?

Answer 23

V shaped growth both in maxilla and mandible

Question 24

Sum up of the transverse diameter:
- it’s higher in boys or girls?
- its higher in mandible or maxilla?
- the largest diameter is reached earlier in the mandible or maxilla? And in boys or girls?

Answer 24

• higher in boys
• higher in maxilla
• earlier in the mandible and in girls

Question 25

In which direction do molars erupt in the mandible?

Answer 25

Mesial and lingual—> convergent

Question 26

In which direction do molars erupt in the maxilla?

Answer 26

Distal and buccal—>divergent

Question 27

The growth in the maxilla occurs through the?

Answer 27

Palatal suture which is open for a long time (18 years old)

Question 28

The growth in the mandible occurs through ?

Answer 28

Apposition

Question 29

How is the arch perimeter measured? And what must we take into account when measuring?

Answer 29

From the mesial surface of the 1st permanent molar following the contour of the buccal cusps until the contralateral 1st permanent molar

Must take into account ONLY the buccal surfaces of the teeth that are in the arch, not those that are outside of it (buccal or linguoversion)

Question 30

Are there changes in the arch perimeter in the maxilla?

Answer 30

Once the permanent teeth have erupted, changes are insignificant

Question 31

Are there changes in the arch perimeter in the mandible?

Answer 31

According to Moorrees, the arch perimeter decreased between 15-18 years old
- 4.48mm in girls, 3.39mm in boys

Question 32

Anterior arch perimeter:
- increases during the?
- maximum perimeter after?

Answer 32

• increase during the eruption of the incisors (buccal)
• maximum perimeter after exfoliation of primary canines

Question 33

Posterior arch perimeter:
- great reduction by?
- other causes of reduction?

Answer 33

• mesial migration of the 1st permanent molar after the exfoliation of the 2nd temporary molars
• tend to mesial displacement of posterior teeth, or attrition of the proximal contacts

Question 34

How is the depth of the arch measured?

Answer 34

At the point of intersection between the line passing through the 2 central incisors and the one passing through the distal side of the 2nd primary molar or 2nd PM

Question 35

Depth of maxilla in primary dentition:

Answer 35

28.5mm

Question 36

Depth of mandible in primary and permanent dentition:

Answer 36

25.2mm

Question 37

Depth of maxilla in permanent dentition:

Answer 37

29mm