Lecture 1

Question 1

Less than 6 congenitally missing teeth:

Answer 1

Hypodontia

Question 2

More than 6 congenitally missing teeth:

Answer 2

Oligodontia

Question 3

Abscence of all teeth:

Answer 3

Anodontia

Question 4

Extra teeth (supernumerary teeth):

Answer 4

Hyperdontia

Question 5

What seven conditions are known to results in congenitally missing teeth?

Answer 5

1. ectodermal dysplasia
2. Hypothyroidism
3. Down syndrome
4. Cleft palate
5. Genetics
6. Radiation
7. Random

Question 6

Groups of syndromes causing missing or peg shaped teeth, thin, sparse hair & absence of sweat glands:

Answer 6

ectodermal dysplasia

Question 7

Cleft palates occur in _____ births

Answer 7

600-800

Question 8

What is the cause of congenitally missing teeth?

Answer 8

Due to disturbances during the initial stages of tooth formation (initiation & proliferation)

Question 9

What specific stages of tooth formation are disturbed resulting in congenitally missing teeth:

Answer 9

Initiation & proliferation

Question 10

T/F: If a primary tooth is missing there is a chance the permanent successor will be present

Answer 10

False- since primary tooth buds give rise to permanent tooth buds, it is not possible for there to be a successor if the primary tooth bud is missing

Question 11

Is it possible to have missing permanent teeth even when there is a primary tooth?

Answer 11

Yes

Question 12

What is the INCIDENCE of hypodontia in the general population?

Answer 12

General population: 2-10% (excluding third molars)

Question 13

What is the INCIDENCE of congenitally missing primary teeth?

Answer 13

0.1% - 0.4%

Question 14

What is the INCIDENCE of congenitally missing 3rd molars?

Answer 14

20% - 25%

Question 15

What sex is hypodontia more common in?

Answer 15

Females (3:2 ratio)

Question 16

T/F: Hypodontia commonly runs in families

Answer 16

True

Question 17

What is the general rule to hypodontia?

Answer 17

As a general rule, if only one or a few teeth are missing, the absent tooth will be the most DISTAL tooth of any given type

Question 18

Missing teeth can be inherited as part of a syndrome or a:

Answer 18

polygenic multifactorial model of etiology

Question 19

What genes are an etiologic factor in hypodontia?

Answer 19

MSX1
PAX9
AXIN2

Question 20

List two medically induced etiologies of hypodontia:

Answer 20

1. cytotoxic drugs
2. radiotherapy

Question 21

T/F: The etiology of hypodontia can be random

Answer 21

True

Question 22

What are the most commonly missing permanent teeth?

Answer 22

Mandibular second premolars
Maxillary second premolars
Maxillary lateral incisors
Maxillary second molars

Question 23

Are maxillary or mandibular second premolars missing more often?

Answer 23

Mandibular second premolars

Question 24

What are the REPLACEMENT treatment options for hypodontia cases?

Answer 24

1. Prosthetically
2. Transplantation
3. Implant

Question 25

What are the treatment options for hypodontia cases?

Answer 25

1. Replacement 2. Extraction of primary tooth to allow tooth drift 3. Extraction followed by ortho 4. Maintain tooth or teeth (occlusal problems to be expected)

Question 26

What must be considered if replacement via implant is the chosen treatment for hypodontia?

Answer 26

Retains primary tooth until close to implant placement time to ensure good bone

Question 27

What do you need for proper canine substitution?

Answer 27

1. similar color to central incisor 2. narrow width of CEJ 3. relatively flat labial surface 4. narrow mid-crown BL width 5. enameloplasty

Question 28

What is the order of canine enamelopalsty?

Answer 28

1. cusp tip 2. mesial & distal (often underperformed) 3. labial ridge 4. add mesial composite 5. line angles

Question 29

Extra, supernumerary teeth have great potential to:

Answer 29

Distrupt normal occlusion

Question 30

What is indicated with supernumerary teeth?

Answer 30

Early intervention to remove them as indicated

Question 31

Is the incidence of HYPERdontia higher or lower than HYPOdontia?

Answer 31

Lower

Question 32

What is the incidence of hyperdontia in primary dentition? Permament dentition?

Answer 32

Primary = 0.5% Permanent= 1.0%

Question 33

If hyperdontia occurs, what percent of the time does it occur in the maxilla?

Answer 33

85%

Question 34

T/F: Hyperdontia occurs in the upper jaw/pre-maxilla area 85% of the time

Answer 34

True

Question 35

Where are mesiodens commonly located?

Answer 35

In the maxillary midline

Question 36

Do mesiodens often exist singularly or in combination?

Answer 36

They are most often singular, but they can also exist in combination

Question 37

Can mesiodens deflect teeth?

Answer 37

Yes

Question 38

What is the general treatment for supernumerary teeth?

Answer 38

Extract before problems arise

Question 39

The more supernumeraries, the more _____, the ____ the positon, the _____ it is to manage

Answer 39

abnormal; higher; harder

Question 40

List the indications for removal of conical supernumerary teeth:

Answer 40

1. if it erupts 2. inverted 3. displacing adjacent teeth 4. producing diastema 5. delaying eruption of permanent tooth

Question 41

When should you NOT remove conical supernumerary teeth?

Answer 41

If the tooth is well above the apices of the permanent tooth, just observe

Question 42

What does a typical supernumerary tooth resemble?

Answer 42

Resembles a normal tooth in morphology and commonly produces crowding or displacement

Question 43

What is the recommended treatment for typical supernumerary teeth?

Answer 43

Extract the tooth more dissimilar to the contralateral tooth unless its severely displaced

Question 44

The recommended treatment for typical supernumerary teeth is to extract the tooth more dissimilar to the contralateral tooth unless:

Answer 44

it is severely displaced

Question 45

What is the incidence of impactions and ectopic eruptions?

Answer 45

Incidence: 1.17% Females 1.17% Males 0.51%

Question 46

What percent of the time does B/L impactions occur?

Answer 46

8%

Question 47

What percent of the time does mandibular canine impactions occur?

Answer 47

0.35%

Question 48

List the etiologies for impactions and ectopic eruptions:

Answer 48

1. local hard tissue obstruction 2. local pathology 3. disturbance of normal development of the incisors 4. hereditary or genetic factors

Question 49

List the signs that might lead you to believe that the canines are impacted:

Answer 49

1. canine is unerupted after 75% of its root development 2. the contralateral tooth has erupted for at least 6 months with complete root formation 3. two years after the adolescent growth spurt has passed 4. 6 months after canine root completion was passed 5. sufficient space for eruption (yet not erupted) 6. arch length deficiency

Question 50

What percent of palatal canine impactions had sufficient space for eruption?

Answer 50

85%

Question 51

83% of labial canine impactions showed an:

Answer 51

arch length deficiency

Question 52

What can be used to diagnosed impacted teeth?

Answer 52

-periapical radiographs -occlusal radiographs -CBCT imaging

Question 53

With periapical radiographs, what technique should be used?

Answer 53

Clark's technique (Slob rule)

Question 54

What degree to the occlusal plane can you see impacted canines on an occlusal radiograph?

Answer 54

110 degree vertex occlusal

Question 55

Are conventional radiographs or CBCT better for accurate and precise examination methods for displaced maxillary canines?

Answer 55

CBCT- conventional radiographs demonstrated a more subjective diagnosis