Dinensional Changes Of Dental Arch

Question 1

Dental arch define.

Answer 1

The measurement through the contact point of teeth

Question 2

Define the alveolar arch.

Answer 2

The measurement of the arch of the alveolar process

Affected by orthodontic movement
Teeth cannot move beyond limits of bone

Question 3

Basal arch

Answer 3

The measurement of apical base arch

Question 4

when does the Late mesial shift occur?

Answer 4

Occurs 11-14 years

Question 5

what is the most important dimension

Answer 5

Arch perimeter

Question 6

Arch depth (length)

Answer 6

Little clinical significance
Reflects circumferential changes

To measure it used the Midline between central incisors tangent distal of primary 2nd molars or premolars

Question 7

intercanine width is increased how

Answer 7

it is slightly increase due to distal tipping of primary canines into primate space while mandibular permanent incisors erupt

Question 8

overbite is correlated to

Answer 8

vertical facial dimensions

Question 9

overjet influenced by

Answer 9

lip , tongue function and digit habits

Question 10

overjet correlated to

Answer 10

anterio posterior skeletal relationship

Question 11

Late lower incisor crowding (tertiary crowding)

Answer 11

One of the most common problems
occurs both in adolescence& post adolescence
High relapse Rate

Question 12

What is the consequences if tertiary crowding is not treated?

Answer 12

Increase crowding

Width and length decrease

Question 13

what are the 3 theories of Late lower incisor (teirtiary)

Answer 13

Lack of “ normal attrition “ in the modern diet

pressure from 3rd molar

Late Mandibular growth:
displaces lower incisors lingually

Question 14

Why does root resorption happen during orthodontic treatment

Answer 14

Movement of teeth back and forth by orthodontic appliances

Duration of treatment

Correction of impacted cuspid

Question 15

Ectopic teeth

Answer 15

teeth that erupt away from their normal position

Question 16

What is the most common ectopic eruption

Answer 16

maxillary 1st molar and canine

Question 17

Treatment of ectopic eruption include

Answer 17

Surgical uncovering
Re-positioning
Orthodontic treatment
early benefit from force of eruption

Question 18

Difference between ectopic and impactation

Answer 18

ectopic teeth : erupt away from normal position

Impacted teeth cannot erupt due to impingement
-Tooth can be both impacted and ectopic

Question 19

What is the most common impacted teeth after 3rd molar

Answer 19

Maxillary canines = 2% caucasians
often requires orthodontic treatment
Palatal impactions 2X as common as buccalaA l impaction

Question 20

Treatment of impacted Max central incisor caused by supernumerary tooth

Answer 20

Remove supernumerary teeth ASAP
in the presence of sufficient space
central incisors superficially placed

Question 21

hypodontia

Answer 21

if patient is missing 1-6 teetth

Question 22

Oligodontia

Answer 22

missing 6+ teeth,

usually bilateral:

Question 23

Anodontia

Answer 23

Complete Absence of teeth

Question 24

What are the most frequently missing teeth?

Rank

Answer 24

1. Mandibular 2nd molar
2. Maxillary Lateral incisors
3. maxillary 2nd premolars

Question 25

Do men or women have more missing teeth

Answer 25

women have more missing teeth

Question 26

Supernumerary teeth

Answer 26

less common than congenitally missing teeth Mostly seen in maxilla- premax region TWICE AS OFTEN IN MEN THAN WOMEN

Question 27

Classification of supernumerary teeth

Answer 27

Teeth with conical crowns Teeth of normal form and size Teeth with abnormal size and cuspal form

Question 28

why do maxillary 1st molars in 3% of north American children have ectopic eruption due to

Answer 28

Large teeth (primary and permanent) Decreased arch perimeter Posterior position of upper arch atypical angle of eruption of the 1st molar.

Question 29

why impacted maxillary canine are common

Answer 29

Deviation from path of eruption Long Path of eruption It relies on lateral incisor root for guidance bc of chronology of eruption:( after 1st premolar) genetic susceptibility

Question 30

when maxillary canines impact what is the palatal impaction vs buccal impaction ratio

Answer 30

Palatal impaction 2/3 | Buccal impaction 1:3

Question 31

what are the effects of aging in teeth and supporting structure

Answer 31

Decrease of pulp chamber size as age increases Clinical crown gets longer due to adaption to vertical jaw growth Passive eruption does not occur if gingival tissues are healthy

Question 32

Passive eruption

Answer 32

Actual gingival migration of the attachment without any eruption of the tooth

Question 33

Inter- premolar(PM) width

Answer 33

slightly increased The center of the premolar crowns are placed more buccally than molar crowns

Question 34

Inter molar width

Answer 34

Inter molar width decreases with late mesial shift

Question 35

what is E Space

Answer 35

the difference in MD width between 2nd molar and 2nd permanent premolar