Development of Dental Arches and Occlusion

Question 1

Development of Dental Arches and Occlusion

What are the four phases of dental development from birth to adult life?

Answer 1

• Period from birth to complete eruption of deciduous teeth (birth to 2-3 years)
• Period from completion of deciduous dentition to eruption of first permanent molars (2-3 to 6 years)
• Mixed dentition period (6 to 12 years)
• Period from eruption of second permanent molars (about 12 years onwards)

Each phase represents a significant stage in the development of the dentition.

Question 2

Development of Dental Arches and Occlusion

What are the gum pads and their characteristics at birth?

Answer 2

Firm and pink in color, they are the alveolar arches at the time of birth.

They develop in two distinct parts: labio-buccal and lingual portions.

Question 3

Development of Dental Arches and Occlusion

What is the sagittal distance of the dental arch at birth?

Answer 3

5 - 6 mm

This measurement is relevant for understanding the initial size of the dental arch.

Question 4

Development of Dental Arches and Occlusion

What is the vertical distance of the dental arch at birth?

Answer 4

2.5 - 3 mm

This dimension helps in assessing the vertical development of the dental arches.

Question 5

Development of Dental Arches and Occlusion

How does the upper gum pad compare to the lower gum pad at birth?

Answer 5

The upper gum pad is wider than the lower.

This contributes to the complete overjet of the upper over the lower gum pad.

Question 6

Development of Dental Arches and Occlusion

What is the relationship between the upper and lower incisor segments of the gum pads?

Answer 6

A vertical space generally exists between them, even when pressed into occlusion.

This space is occupied by the tongue and does not necessarily indicate an anterior open bite.

Question 7

Development of Dental Arches and Occlusion

What role does the tongue play in the positioning of the gum pads at rest?

Answer 7

The tongue separates the gum pads and may protrude over the lower gum pad.

This positioning may occur immediately behind the lower lip and could even extend slightly between the lips.

Question 8

Development of Dental Arches and Occlusion

True or False: The vertical space between the upper and lower incisor segments indicates a dental issue.

Answer 8

False

The space occupied by the tongue is a normal occurrence and does not imply an anterior open bite.

Question 9

Development of Dental Arches and Occlusion

Fill in the blank: The mixed dentition period occurs from the eruption of the first permanent molars to the final shedding of the deciduous teeth, typically from ____ to ____ years.

Answer 9

6 to 12

This phase is critical for understanding the transition from primary to permanent teeth.

Question 10

Development of Dental Arches and Occlusion

When does the first primary incisor typically erupt?

Answer 10

6 – 8 months

Question 11

Development of Dental Arches and Occlusion

What is the eruption timing for the second primary incisor?

Answer 11

8 – 12 months

Question 12

Development of Dental Arches and Occlusion

At what age does the first primary molar usually erupt?

Answer 12

12 – 16 months

Question 13

Development of Dental Arches and Occlusion

When do primary canines typically erupt?

Answer 13

16 – 20 months

Question 14

Development of Dental Arches and Occlusion

What is the eruption timing for the second primary molar?

Answer 14

20 – 30 months

Question 15

Development of Dental Arches and Occlusion

What age range defines the first period of primary dentition?

Answer 15

Eruption of first temporary tooth to 2.5 - 3 years old

Question 16

Development of Dental Arches and Occlusion

When does the eruption of primary teeth usually begin?

Answer 16

About 6 months after birth

Question 17

Development of Dental Arches and Occlusion

By what age are all primary teeth usually erupted?

Answer 17

2 ½ years of age

Question 18

Development of Dental Arches and Occlusion

What significant dental event occurs at about 3 years of age?

Answer 18

Establishment of primary dentition

Question 19

Development of Dental Arches and Occlusion

What age marks the beginning of the second period of primary dentition?

Answer 19

2.5 – 3 years old

Question 20

Development of Dental Arches and Occlusion

What is the age range for primary stable dentition?

Answer 20

5.5 – 6 years old

Question 21

Development of Dental Arches and Occlusion

At what age does the dental arch begin to change due to the eruption of first permanent molars?

Answer 21

5 – 6 years of age

Question 22

Development of Dental Arches and Occlusion

What age is associated with the development of the apical base?

Answer 22

About 4 years old

Question 23

Development of Dental Arches and Occlusion

What are the characteristics of primary dentition teeth?

Answer 23

• Short clinical crowns
• Pronounced equators
• Opened roots

Question 24

Development of Dental Arches and Occlusion

What are the characteristics of the primary dental arch?

Answer 24

• Spaced anterior teeth
• Primate spaces
• Shallow overbite and overjet
• Straight terminal plane
• Almost vertical inclination of anterior teeth
• Ovoid arch form
• Almost no curve of Spee

Question 25

# Development of Dental Arches and Occlusion Fill in the blank: The eruption of primary teeth begins at about _______ after birth.

Answer 25

6 months

Question 26

# Development of Dental Arches and Occlusion True or False: The roots of the second primary molars are usually complete by the time they erupt.

Answer 26

False

Question 27

# Development of Dental Arches and Occlusion What are the three types of dental arches according to Vladislavov?

Answer 27

* With diastema and spacing over 0.5 mm * Without diastema and spacing * Crowded teeth ## Footnote These classifications help in understanding the arrangement and spacing of teeth in the dental arch.

Question 28

# Development of Dental Arches and Occlusion What is the significance of primate spaces in dental arches?

Answer 28

* More favorable alignment of permanent incisors * Aids in proper molar occlusion ## Footnote Primate spaces are crucial for the transition from primary to permanent dentition.

Question 29

# Development of Dental Arches and Occlusion What is the normal value for overjet?

Answer 29

2-3 mm ## Footnote Overjet is the horizontal overlap between the mandibular and maxillary incisors.

Question 30

# Development of Dental Arches and Occlusion Describe the occlusal relationship established at birth between the mandibular and maxillary arches.

Answer 30

The mandibular arch is posterior to the maxillary arch ## Footnote This relationship changes with the eruption of primary molars.

Question 31

# Development of Dental Arches and Occlusion What does the term 'flush terminal plane' refer to in primary dentition?

Answer 31

The mandibular second deciduous molar is wider mesiodistally than the maxillary ## Footnote This results in a specific occlusal relationship at the end of primary dentition.

Question 32

# Development of Dental Arches and Occlusion What is the definition of overbite?

Answer 32

The **vertical labial overlap** of the maxillary incisors over the mandibular incisors ## Footnote Overbite is a key factor in dental occlusion.

Question 33

# Development of Dental Arches and Occlusion How does the overbite change with the eruption of deciduous molars?

Answer 33

It is reduced progressively by the eruption of deciduous molars and more rapid attrition of incisors ## Footnote This process is crucial for proper dental alignment.

Question 34

# Development of Dental Arches and Occlusion What is the typical time frame for posterior teeth to reach the alveolar crest after crown completion?

Answer 34

2 to 5 years ## Footnote This duration can vary based on individual development.

Question 35

# Development of Dental Arches and Occlusion How long does it take for posterior teeth to reach occlusion after reaching the alveolar margin?

Answer 35

12 to 20 months ## Footnote This is an important phase in the eruption process.

Question 36

# Development of Dental Arches and Occlusion What happens to the roots of teeth after occlusion is attained?

Answer 36

The roots usually are completed a few months after occlusion ## Footnote This highlights the ongoing development of teeth even after they have erupted.

Question 37

# Development of Dental Arches and Occlusion Fill in the blank: The spacing of deciduous teeth is _______.

Answer 37

variable ## Footnote This variability can affect the eruption and alignment of permanent teeth.

Question 38

# Development of Dental Arches and Occlusion What is the sequence of eruption for maxillary teeth that accounts for almost half of the cases?

Answer 38

6-1-2-4-3-5-7 and 6-1-2-4-5-3-7 ## Footnote These sequences demonstrate significant variability in the arrival of teeth.

Question 39

# Development of Dental Arches and Occlusion What is the sequence of eruption for mandibular teeth that includes more than 40% of the cases?

Answer 39

6-1-2-3-4-5-7 and 6-1-2-4-3-5-7 ## Footnote Variability in the sequence of tooth eruption is clinically important.

Question 40

# Development of Dental Arches and Occlusion What is the age range for the first stage of mixed dentition development?

Answer 40

6.5 – 9 years ## Footnote This stage includes the eruption of M1 and incisives.

Question 41

# Development of Dental Arches and Occlusion What occurs during the second stage of mixed dentition development?

Answer 41

Eruption of premolars and canines ## Footnote This stage has two phases: 9-10.5 years (no active growth) and 10.5-12 years (active growth).

Question 42

# Development of Dental Arches and Occlusion What is the tendency of mandibular permanent incisors during eruption?

Answer 42

To erupt somewhat lingually and to a slightly irregular position ## Footnote This occurs even in children with normal dental arches.

Question 43

# Development of Dental Arches and Occlusion What is the difference between the space needed and the space available for mandibular incisors called?

Answer 43

Incisor liability ## Footnote This difference leads to slight crowding of mandibular permanent incisors at ages 8 to 9.

Question 44

# Development of Dental Arches and Occlusion What compensates for incisor liability?

Answer 44

*Interdental spacing *Intercanine arch width growth *labial positioning *Favourable size ratio *Increase of anterior length ## Footnote These factors help in the alignment of larger permanent incisors.

Question 45

# Development of Dental Arches and Occlusion What happens to primary incisors as permanent incisors erupt?

Answer 45

There is an exchange of primary incisors ## Footnote This process occurs during the eruption of permanent incisors.

Question 46

# Development of Dental Arches and Occlusion Position from which maxillary central incisors erupt

Answer 46

Labial ## Footnote The positioning of the permanent incisor tooth buds affects their eruption.

Question 47

# Development of Dental Arches and Occlusion What is the average space difference in the mandibular arch when lateral incisors erupt?

Answer 47

1.6 mm less space available for the 4 mandibular incisors ## Footnote This space difference impacts alignment.

Question 48

# Development of Dental Arches and Occlusion True or False: The permanent incisor teeth are smaller than the primary teeth.

Answer 48

False ## Footnote Permanent incisors are considerably larger than primary teeth.

Question 49

# Development of Dental Arches and Occlusion What is the difference in MDW of primary and permanent incisors?

Answer 49

About 6.5 - 7 mm ## Footnote MDW stands for mesiodistal width.

Question 50

# Development of Dental Arches and Occlusion How does the arch compensate for the difference in MDW of incisors?

Answer 50

* By physiologic growth * By physiologic spaces * By vestibular eruption, increasing the width and length of the upper arch

Question 51

# Development of Dental Arches and Occlusion How does the arch compensate for the difference in primary and permanent canine sizes?

Answer 51

* By physiologic growth * By physiologic spaces (primate spaces) * By medialisation of incisors and distal movement of premolars

Question 52

# Development of Dental Arches and Occlusion When is the transverse growth completed for the maxilla?

Answer 52

Between 13 – 15 years

Question 53

# Development of Dental Arches and Occlusion When is the transverse growth completed for the mandible?

Answer 53

Between 10-12 years

Question 54

# Development of Dental Arches and Occlusion How is space ensured for premolars?

Answer 54

The sum of MDW of the premolars is less than the sum of MDW of deciduous molars

Question 55

# Development of Dental Arches and Occlusion Where will molars grow in the dental arch?

Answer 55

In a new place in the dental arch

Question 56

# Development of Dental Arches and Occlusion What happens to the distal space as the arch grows?

Answer 56

It increases with the growth of the arch

Question 57

# Development of Dental Arches and Occlusion What happens to the anterior length of the dental arch in the sagittal direction?

Answer 57

It increases to accommodate larger permanent incisors.

Question 58

# Development of Dental Arches and Occlusion What is the labial movement of permanent incisors in the anterior maxilla?

Answer 58

2.2 mm.

Question 59

# Development of Dental Arches and Occlusion What is the labial movement of permanent incisors in the anterior mandible?

Answer 59

1.3 mm.

Question 60

# Development of Dental Arches and Occlusion What causes the reduction in sagittal direction?

Answer 60

Smaller MDW of permanent premolars compared to primary teeth.

Question 61

# Development of Dental Arches and Occlusion What is leeway space?

Answer 61

The **sum of the differences in MDW** of certain teeth=> * That allows for more space.

Question 62

# Development of Dental Arches and Occlusion What does the leeway space sum of (c-d-e) need to exceed?

Answer 62

(3-4-5).

Question 63

# Development of Dental Arches and Occlusion What is the average leeway space in the mandibular buccal segment?

Answer 63

1.7 mm.

Question 64

# Development of Dental Arches and Occlusion What is the average leeway space in the maxillary buccal segment?

Answer 64

0.9 mm.

Question 65

# Development of Dental Arches and Occlusion Flush terminal plane

Answer 65

Upper and lower deciduous second molars' distal surfaces are in one vertical plane

Question 66

# Development of Dental Arches and Occlusion Mesial step

Answer 66

Distal surface of mandibular deciduous second molar mesial to distal surface of maxillary deciduous second molar

Question 67

# Development of Dental Arches and Occlusion Distal step

Answer 67

Distal surface of lower primary second molar is distal to upper primary second molar

Question 68

# Development of Dental Arches and Occlusion What is the appearance of mixed dentition in the transversal direction?

Answer 68

Vestibular cusps of mandibular posterior teeth occludes in central fossaes of the maxilla posterior teeth.

Question 69

# Development of Dental Arches and Occlusion What is the term for the vertical labial overlap of the maxillary incisors over the mandibular incisors?

Answer 69

Overbite

Question 70

# Development of Dental Arches and Occlusion What is considered a normal overbite measurement?

Answer 70

2-4 mm

Question 71

# Development of Dental Arches and Occlusion What proportion of the height of the crowns of the mandibular incisors does normal overbite approximate?

Answer 71

1/3rd

Question 72

# Development of Dental Arches and Occlusion When is the physiological bite opening associated with the eruption of the first permanent molars?

Answer 72

Between 6-7 years

Question 73

# Development of Dental Arches and Occlusion List the three periods of physiological raising of the bite.

Answer 73

* With the eruption of **first primary molar** at the age of 2.5 * With the eruption of **first permanent molar** at the age of 6 * With the eruption of **second permanent molars and canines** at the age of 12

Question 74

# Development of Dental Arches and Occlusion What occurs if the diastema is less than 2 mm?

Answer 74

Spontaneous closure occurs and therefore treatment is not indicated. ## Footnote Diastema refers to a gap between teeth.

Question 75

# Development of Dental Arches and Occlusion What happens if the diastema is greater than 2 mm?

Answer 75

Spontaneous closure is unlikely, therefore treatment is indicated. ## Footnote Treatment may involve orthodontic intervention.

Question 76

# Development of Dental Arches and Occlusion What is the ugly duckling stage?

Answer 76

A normal developmental stage that should not be mistaken for malocclusion. ## Footnote It involves the crowns of canines impacting the roots of lateral incisors.

Question 77

# Development of Dental Arches and Occlusion What effect do the crowns of the canines have on the developing roots of the lateral incisors?

Answer 77

They drive the roots medially and cause the crown to flare laterally. ## Footnote This stage is common in mixed dentition.

Question 78

# Development of Dental Arches and Occlusion How do mandibular incisors erupt?

Answer 78

Erupt lingually. ## Footnote This position is important for achieving proper occlusion.

Question 79

# Development of Dental Arches and Occlusion What is the significance of having enough space for mandibular incisors?

Answer 79

Good position is achieved. ## Footnote Lack of space can lead to misalignment.

Question 80

# Development of Dental Arches and Occlusion What happens with a lack of space of 1-2 mm for mandibular incisors?

Answer 80

Compensation occurs=> * Physiological increase ## Footnote This can help maintain alignment despite limited space.

Question 81

# Development of Dental Arches and Occlusion What does late mesial shift refer to?

Answer 81

Mandibular permanent molar moving mesially. ## Footnote This shift is crucial for achieving proper occlusion.

Question 82

# Development of Dental Arches and Occlusion What is the result of the late mesial shift?

Answer 82

Allows mandibular molar to move into a Class I occlusion and reduces arch length. ## Footnote Class I occlusion is considered a normal bite.