Age Determination- Teeth
| A | Attrition | |
| B |
Secondary dentine deposition |
|
| C |
Root resorption |
|
| D |
Root transparency |
Among the secondary changes in tooth the most useful one for age determination is:
| A |
Attrition |
|
| B |
Secondary dentine deposition |
|
| C |
Root resorption |
|
| D |
Root transparency |
Gustafson’s criteria is used to determine the age base on the secondary changes in the tooth.
Among the criteria transparency of the root is considered to be the single most important one in age determination.
In this, the two opposite sides of an extracted or naturally fallen tooth is ground uniformly to thin in upto less than 1mm thickness.
Then its transparency is assessed and and the age is estimated with the help of a regression line prepared by study in the translucency of teeth of known ages.
- Attrition
- Periodontosis
- Secondary dentin
- Cementum apposition
- Root resorption
- Root transparency
Eruption of temporary teeth will be completed by :
| A | One to one and half year | |
| B |
Two to two and half year |
|
| C |
Three to four years |
|
| D |
Four to five years |
B i.e. 2-21/2 years
A girl of 10 years will have….. permanent and……. temporary teeth :
| A |
8,12 |
|
| B |
8,16 |
|
| C |
16,8 |
|
| D |
12,12 |
C i.e. 16, 8
The primary dentition begins to show teeth eruption by-
| A |
6 weeks |
|
| B |
12 weeks |
|
| C |
6 months |
|
| D |
12months |
Ans. is ‘C
As seen from the chart, the first teeth begin to break through the gums at about 6 months of age. Usually, the first two teeth to erupt are the two bottom central incisors (the two bottom front teeth).
o Rule of six :-
Primary (temporary) dentition begins —> 6 months.
Secondary (permanent) dentition begins —> 6 years.
| A |
5 years |
|
| B |
6 years |
|
| C |
7 years |
|
| D |
8 years |
Ans. is ‘b’ i.e., 6 years
o First primary (milk) tooth erupts at 6 months.
o First secondary (permanent) tooth appear at 6 year of age.
Delayed dentition is seen in all/except ‑
| A |
Down syndrome |
|
| B |
Congenital hypothyroidism |
|
| C |
Rickets |
|
| D |
All of above |
Ans. is ‘d’ i.e., All of above
Causes of delay in tooth eruption :
- Impacted teeth
- Cong hypothyroidsm
- Down syndrome
- Gaucher
- Cleidocranial dysplasia
- Osteo petrosis
| A | Hypothyroidism causes delayed dentition | |
| B |
Premolar is not seen in primary dentition |
|
| C |
3rd molar is the last to appear in secondary dentition |
|
| D |
All |
Ans. is ‘a’ i.e., Hypothyroidism causes delayed dentition; ‘b’ i.e., Premolar is not seen in primary dentition; ‘c’ i.e., 3rd molar is the last to appear in secondary dentition
All are true about permanent teeth, except:
MP 11
| A |
Ridge is present between neck and body |
|
| B |
Anterior teeth are inclined forward |
|
| C |
Roots of molars are larger |
|
| D |
They are ivory white in color |
Ans. Ridge is present between neck and body
First permanent tooth to arise:
AP 10; UPSC 11; Delhi 11
| A |
Incisor |
|
| B |
Canine |
|
| C |
Premolar |
|
| D |
Molar |
Ans. Molar
The period of mixed dentition is between the age of:
UP 11
| A | 2-9 years | |
| B |
6-11 years |
|
| C |
12-14 years |
|
| D |
16 years |
Ans. 6-11 years
Number of permanent teeth at 8 years:
| A |
6 |
|
| B |
8 |
|
| C |
12 |
|
| D |
16 |
Ans. C. 12
|
Tooth Lateral incisor (upper) |
Eruption 7 to 9 months |
|
Lateral incisor (lower) |
10-12 months |
|
First molar |
12 to 14 months |
|
Canine |
17 to 18 months |
|
Second molar |
20 to 30 months |
|
Tooth First molar |
Eruption 6 to 7 years |
|
Central incisor |
6 to 8 years |
|
Lateral incisor |
7 to 9 years |
|
First bicuspid |
9 to 11 years |
|
Second bicuspid |
10 to 12 years |
|
Canine |
11 to 12 years |
|
Second molar |
12 to 14 years |
|
Third molar |
17 to 25 years (17-21 in Parikh 6th/2. 7) |
False with regard to permanent teeth is:
TN 08
| A | Molars erupt around 6 years | |
| B |
Dentigerous cyst is common in canines |
|
| C |
There are 16 permanent teeth at the age of 10 years |
|
| D |
3rd molars eruption is variable |
Ans. Dentigerous cyst is common in canines
Age of eruption of Permanent 1st molor ‑
| A |
6 years |
|
| B |
8 years |
|
| C |
10 years |
|
| D |
12 years |
Ans. is ‘a’ i.e., 6 years
