Lecture 2

Question 1

What is the first stage of eruption?

Answer 1

• Occurs at age 6

- Contains mandibular central, mandibular first molars and maxillary first molars

Question 2

Dental age 8 is characterized how?

Answer 2

-Eruption of the maxillary lateral incisors

Question 3

What age to most patients receive phase I orthodontic treatment if necessary?

Answer 3

-Dental age 8

Question 4

What characterizes dental age 11?

Answer 4

• Eruption of the mandibular canines
• Mandibular first premolars
• maxillary first premolars

Question 5

What is considered the best stage of development to start full orthodontic treatment or phase II treatment?

Answer 5

-Dental age 11

Question 6

What characterizes dental age 12?

Answer 6

• Eruption of the maxillary canine
• maxillary second premolars
• Mandibular second premolars
• Mandibular and maxillary second molars erupt a few months later

Question 7

What characterizes dental age 15?

Answer 7

-Roots of all permanent teeth except third molars are complete

Question 8

For pre-emergent eruption to occurs what has to happen?

Answer 8

• First (resorption of the bone and the primary tooth roots)

- Second (Propulsive mechanism to move the tooth in the direction where the overlying path has been cleared)

Question 9

Cleidocranial dysplasia is caused by a mutation in what?

Answer 9

-CBFA1 gene

Question 10

In cleidocranial dysplasia, the permanent teeth do not erupt because of what reason?

Answer 10

-Abnormal resorption of both the overlying bone and primary teeth

Question 11

T/F The rate of bone resorption and the rate of tooth eruption are controlled physiologically by the same mechanisms

Answer 11

False

-They are not controlled by the same mechanism

Question 12

What is the rate limiting factor in pre-emergent eruption?

Answer 12

-Resorption of the overlying bone and primary tooth

Question 13

T/F when the overlying obstructions are removed the tooth can typically erupt

Answer 13

True

Question 14

If the eruption of a tooth is mechanically blocked the proliferating apical area will do what?

Answer 14

-Move in the opposite direction that could lead to a dilaceration

Question 15

What is primary failure of eruption?

Answer 15

-Failure of permanent teeth to erupt in the absence of mechanical obstruction

Question 16

T/F In Primary failure of eruption the more posterior the teeth are the less frequently they are affected

Answer 16

False

-The more they are affected

Question 17

T/F PFE is typically seen as being symmetrical

Answer 17

False

-Asymmetrical

Question 18

What are the two phases of post-emergent eruption?

Answer 18

• Juvenile phase

- Adult phase

Question 19

When does the juvenile phase begin?

Answer 19

-Once a tooth emerges into the mouth

Question 20

Tooth eruption is stopped by a force for what time period?

Answer 20

-One to three minutes

Question 21

What two forces oppose eruption of teeth?

Answer 21

• Chewing forces

- Soft tissue forces (lips cheeks and tongue)

Question 22

T/F Soft tissue pressure are probably more important in controlling tooth eruption that the heavy pressures that occur during chewing

Answer 22

True

Question 23

What can cause a posterior open bite?

Answer 23

• Primary failure of eruption
• Ankylosis
• Lateral tongue thrust