chronology of tooth development

8/3/2019 Chronology of Tooth Development

1/20

1

Chronology of tooth development

The Topic of todays lecture is chronology of tooth development .We will

talk about tooth development and eruption: The sequence, the order and

the approximate time in which each tooth, whether a deciduous or apermanent, will erupt.

What does chronology mean?

Chrono means time , logy mean science so here we are talking about the

science of time in relation to the development of the dentations , we know

the primary (deciduous) and the secondary (permanent) dentition, so

chronology deals with the timing of different stages of development .

Why do we need to know the timing of teeth development in dentistry?

1) To know the abnormal problems , for example , if I told you that the

lower deciduous central incisors appear at 8 month normally and you

have your little brother with an age on 1.5 year and still you havent

seen any tooth in his mouth the you know that theres something

wrong. So we need to know the normal cases to detect the abnormalones.

2) In the field of orthodontics , they have to know the order and the

sequence of the teeth development in order to adjust, detect and

treat the patient orthodentically.

3) In Forensic dentistry sometimes when we have

massive disasters, like aircraft crash, and we

have body remains, we identify these remains by

checking the development of bones such as skullor by looking for the sequence or presence of the

teeth, then looking back in the passengers

records and identifying the person.

4) In pediatric dentistry as if you extract a deciduous tooth early you

have to keep enough space for the permanent tooth to erupt in the

Forensic dentistry orforensic

odontology is the proper

handling, examination andevaluati

on ofdentalevidence, which will

be then presented in the interest

ofjustice.

Wekipedia


2/20

2

right place , for example if you as a dentist has a child 6-7 years old

with disastrous tooth that cant be treated so the only option is to

extract this tooth, in this case we cant extract this tooth without

maintain the space for the permanent tooth to erupt correctly ( this is

called space maintenance), but u have to estimate the age of thatchild to know to use the space maintenance or not , for example a

child is 11 years old that u need to extract his tooth but u know that

in his age after 6 months his permanent teeth will appear so we dont

have to maintain the space because the permanent tooth will erupt

soon but again if the child too young 6-7 years old we have the

maintain the space .

** How to estimate the age depending on looking at the teeth?

Example:We saw a child with Lateral incisors and we know that lateral incisorserupt at age 8 so we conclude that the age of this child above 8years.But at the same time we dont see the mandible canine which erupt atthe age of 10 so this child is younger than 10 , so finally we concludethat the age of this child between 8-10 years .

P

.S : ( about spacemaintenance )

After and extraction of a tooth , the neighboring teeth will try to fill up that

space by moving toward each other in an abnormal way , not leaving

enough space for the permanent tooth to erupt in its normal position

replacing the extracted tooth.


3/20

3

** Mixed dentition stage:

It is the Case when we have both deciduousand permanent teeth in the mouth at thesame time (two sets of dentition deciduous

and permanent at the same time.)It is also called "Transition Destination Stage"

Why do we have to have two sets of teeth ?Because when the teeth complete their development they dont growin size while the other bones grow in size and length, So if you have

just one set of teeth by the age of 14 you will end with very big jawand very small teeth, and you will not function properly using thisteeth, thats why you need to have new set of teeth with** two important characteristics:1- Bigger in size.2- More in number.

** Remember:1. Orthodontic

2. Pediatric dentistry

3. Forensic dentistry

- Are very important areas for the application of the chronology of tooth

development .


4/20

4

- This skull shows that the whole deciduous teeth

have erupted . The last deciduous tooth to erupt is

the second molar at the age of 2 and a half. The

first permanent tooth to erupt is the first molar at

age of 6 which hasnt erupted yet.

By this we can say that this child is between the

age of 2.5 to 6 years .

- All of the deciduous teeth are formed

and all of them have almost complete

roots .But regarding to the permanent

teeth not all of them are formed yet .

- If we look at the mandible we can see

that the crown of the first permanent

molar is almost full but there is no rootsyet .

- We can see that all of the permanent

teeth are fully erupted. In addition, we

can see the maxillary and mandibular

third molar , which erupts at the age letus say 22 , by this we can estimate that

these are the teeth of an adult who is

more that 22 years in age .


5/20

5

- This model shows :

1) Permanent central and lateral incisors.

2) Deciduous canines and underneath them the

permanent ones .3) Deciduous first and second molars with the

first and second permanent premolars

underneath.

4) The permanent first molar.

5) The permanent second molar which has not

erupted yet.

- We can see that the last permanent tooth erupted was the lateral incisor

which usually erupts at age of 8 years. The next permanent tooth to erupt is

the mandibular canine which erupts at age of 10 is not there yet . so we

can estimate the age which is in here from 8 to 10 years old .

- "Prince Ahmed" asked the doctor: when you say erupt did you mean

erupt going out or just formation of the tooth? the answer is: No, eruption

means when the tooth starts to appear in the mouth, when you start to seethe tooth in the mouth this is called eruption.


6/20

6

This table will show you different teeth and the different stages of

development related to different teeth.

For example:

If I come to a type at the age of3 years, what teeth should I see?

I will see the central incisor , only half of the crown has formed, lateral

incisor maybe one third of the crown, canine only the cusp, but notice that I

can see that the first molar has completed its crown, and the second molar

I can see the very beginning of develop. So thats why they cant develop at

the same time, each tooth develops specifically at different states of time.


7/20

7

- Lets start the story from the beginning. Why do we

see teeth for a child in the uterus before birth?

At the age offive months the baby still not born yet,you can see some deciduous teeth not permanent

teeth of course. You can see the incisor edge of the

central incisor, part of the incisor edge of the lateral incisor, some

development of the third deciduous molar and very small development of

the canine.

At the age ofseven months you can see the central

incisor, lateral incisor, canine and first deciduous molar.

Also you can see the initiation of development of the

second deciduous molar.

At Birth when the child is born, You can see most of the

crown of the central incisor and the lateral incisor, thetip of canine, and the development of maxillary first

deciduous molar.

This means that maxillary first deciduous molar

precedes the canine, Although its located after it.Plus

that you can see some development of the cusp of

maxillary and mandibular second deciduous molar.

* Notice that NO TEETH ARE ERUPTED AT BIRTH .

This is th

Gum


8/20

8

We dont see any development of permanent teeth at

birth, we only see deciduous teeth, but atsix months

of age we started to see some development of tooth ,

which is the permanent first molar.

Also you can see the initiation of development of

the maxillary central incisor, mandible central

incisor and some development of the lateral incisors. Thats why you can

see the beginning of appearance of mandibular central incisor then the

upper central incisor, after that the lower lateral incisor, finally the upper

lateral incisor.

* you should memorize the sequence.

At the age ofnine months we can see more

filtration in oral mucosa , so we can see 3 quarters

of the crown of the first permanent premolar are

appearing in the mouth, and less appearance for

the permanent lateral incisor than the permanent

central.

At this age we still dont see any eruption of deciduous teeth, only we

see eruption of the central and lateral incisors of deciduous teeth. But

also at this age the development of almost half of crown of the

permanent first molar have formed, and some crowns formation for the

central, lateral and lower canine. We have some crown formation for the

central and lateral incisors.

* Its Better if you check the slide's pictures to compare between

Permanent and deciduous by the color , ( Grey = Deciduous ,Brown = Permanent ) .

* (+/- ) 2 Months , refers to the (range) , That The Time May Be

Less Or More By Two Months .


9/20

9

-At the age ofone yearwe have new tooth appearing in

the mouth , notice that the first tooth after the incisors is

not the deciduous canine, you will see central then

lateral then deciduous first molar Not the canine . This

sequence is very important . also we can see the moredevelopment of permanent anterior teeth as well .

At the age of Two years notice that most of the deciduous teeth appear in

the mouth as you see in the picture. But notice that although all the teeth

appear in the mouth But not all the teeth come into contact , all the anterior

teeth are in contact now But the posterior teeth are Not in contact although

they appear. This means that this teeth will penetrate into the spaces untilthey make contact ( this is called the occlusal contact ) .

- At the age ofsecond yearas well we can see almost or

less than the full development of the crown of the first

permanent molars .

- At the age of 3 years All the deciduous teeth are erupted and they are in

contact . By this age the child will be able to use the deciduous dentition

functionally very well . It is the age of completion of the

crown of the permanent first molar.


10/20

10

- At the age of4 years all the deciduous teeth are

erupted and also the crown of the first permanent molar

is completed , and also we can see some development

of the roots of the first permanent molar .

* Before 6 years we dont see any permanent tooth.

- But with the start of6 years we start to see new

permanent teeth , which is the maxillary and mandible

first molar .

- At the age of7 years , There are more development

until these 2 teeth become in contact , the child start to

lose teeth at the age of 7 years . When the deciduous

central incisors are replaced by permanent central

incisors .

- At the age of10 years ,More lost of the deciduous

teeth take place , and also more development and

apparent of permanent teeth , and this appears in asequence :

1- The Permanent lower central2- The Permanent lower lateral3- The Permanent upper lateral4- The Permanent lower canine5- The Permanent lower first premolar6- The Permanent upper first premolar ,7- Then this three teeth erupt together ( the upper canine and the

upper 1st and 2nd premolars the lower 1st and 2nd premolars ).

** Notice that at the age of 10 years we have some development of the

second molar , and also the beginning of the development of the last tooth (

third molar )


11/20

11

- At the age of12 years , All the deciduous teethare lost , so this is the end of the ( Mixeddeciduous dentition stage ).

* Why it is ended ?because all the deciduous has lost , So the mixed deciduous dentitionstag starting at the eruption of the first permanent teeth , and endingby losing last deciduous teeth .

If I ask you an exam question and answer true or false

y Q1 ) The first permanent tooth that erupt is the mandibular central

incisor ?

Answer: false , it is the permanent first molar

y Q2) The first successor permanent tooth that erupt is the mandibular

central incisor ?

Answer : True , because molars is non successor permanent , butincisor is successor permanent tooth ( successor mean follows =replaced )


12/20

12

That's why we can think about different stages of tooth development :

1- The first stage ( from birth until 6 months ) during that stage we dont

have any teeth in the mouth* of course you know that all the teeth are represented in the jaw but not

appearing in the mouth , we call this stage (edentulous stage ) we will

come to this stage later on . an edentulous mean = no teeth .

2- The (primary deciduous stage) , (from 6 months to 3 years ) during this

stage we will start to see teeth one by one eruption until 3 years, when all

the teeth come in the mouth and they come in contact .

* By this stag now the child is able to use his teeth functionally very well .

This is why after 3 years we start to name it ( the functional deciduous

dentition stage ) . from 6 month to 3 years , until the apparent of the first

permanent teeth

3- Before 6 years we dont see any permanent tooth ,That is why we end

the functional deciduous dentition stags to begin new dentition stages

which is the (mixed dentition stage).

4- The permanent dentition stage . This stage is not fully functionally yet ,

there are some spaces between the molars ( second molars ) , once this

second molars come into complete contact ( as in the picture ) we start to

call it.

5- The functional permanent dentition stages , at 15 years old .

*** Usually we dont rely on third molar ( wisdom teeth) in naming the

different stages , because sometimes they are not present or impacted ,

thats why at the age of 15 years when these second molars becomes in

contact it is the beginning of the functional permanent dentition stage , and

it remains until the teeth start to be lost by very old ages .


13/20

13

** Here is a summary about the teeth

development of different stages, and the

sequences of those development .

- Here we are giving numbers to the teeth and these numbers are the

sequence of eruption not the palmar notation numbers .

(( Recall from the introduction to dentistry that the mandibular teeth arises

before the maxillary ones even if their average of eruption is in the same

time .))


14/20


15/20

15

Order of Eruption (Inter-arch) in Jordanian population :

The order for the permanent teeth :

1- Lower central incisor, lower first molar and upper first molar

2- Maxillary central incisor

3- Mandible lateral incisor

4- Maxillary lateral incisor

5- Mandibular canine , mandibular first premolar and maxillary first

premolar

6- Second premolars upper and lower ones and upper canine

** If we dont have enough space in the mouth for the teeth to erupt the

tooth that will be mostly affected is the upper canine because the premolar

which come after it anatomically precedes it in the eruption so there is a

chance that this premolar wont let enough space for the canine to come

out .

7- Mandibullar second molar

8- Maxillary second molar

9- Third molars upper and lower

Notice thatThis is an :

*(Inter- arch sequence) which is according to the time of eruption in botharches : maxillary and mandibular arches together .


16/20

16

- In the same way we can arrange the time of eruption for each arch

separately -within the same arch- that is called (Intra-Arch Sequence )

Order of eruption for permanent teeth (Intra-arch) :

sequence For the maxilla For the mandible

1 First molar Central incisor + firstmolar

2 Central incisor Lateral incisor

3 Lateral incisor Canine + first premolar

4 First premolar Second premolar

5 Canine + second premolar Sec molar

6 Second molar Third molar

7 Third molar

Order of eruption for deciduous teeth ( Intra-arch) :

sequence For the maxilla For the mandible

1 Central incisor Central incisor

2 Lateral incisor Lateral incisor + firstmolar

3 First molar Canine

4 Canine Second molar

5 Second molar


17/20

17

Timing of emergence of permanent teeth in

Jordanians (Shaweesh, 2012A)

Tooth

Combined gender Males Females

Median

age

Percentile Median

age

Percentile Median

age

Percentile

5th 95th 5th 95th 5th 95th

Maxillary

1 7.18 5.80 8.56 7.25 5.78 8.71 7.11 5.84 8.39

2 8.26 6.47 10.06 8.45 6.51 10.39 8.07 6.52 9.61

3 11.30 8.91 13.70 11.56 9.09 14.04 11 .09 8.74 13.43

4 10 .23 7.79 12.66 10.45 7.96 12.94 10 .01 7.65 12.38

5 11.17 8.69 13.65 11.37 8.87 13.88 11 .00 8.53 13.47

6 6.27 5.01 7.52 6.35 5.25 7.45 6.20 4.81 7.59

7 12 .44 10.14 14.74 12.61 10.3 14.92 12 .32 9.98 14.65

Mandibular

1 6.40 5.16 7.63 6.48 5.38 7.59 6.32 5.00 7.65

2 7.43 5.99 8.87 7.51 6.05 8.97 7.34 5.94 8.74

3 10 .23 8.01 12.45 10.63 8.30 12.97 9.84 7.86 11.82

4 10 .32 7.96 12.69 10.54 8.11 12.98 10 .12 7.83 12.41

5 11.44 8.87 14.00 11.73 9.13 14.32 11 .20 8.65 13.74

6 6.16 4.88 7.45 6.24 5.16 7.32 6.08 4.66 7.50

7 11.90 9.47 14.33 12.19 9.87 14.51 11 .66 9.13 14.19

This slide

- Usually females erupt their teeth before males .

- Combined gender data : data that can be used for males and females at

the same time .

- Percentile: the normal range (time) for a teeth to erupt, it is important in

telling if the eruption in a person is normal or not .

- Here we can see that data are in years because it is for permanent teeth .

We have to memorize the Median age for eruption in the maxilla and

the mandible .

Timing of emergence of deciduous teeth in

Jordanians (Shaweesh et al*)

5th 95th 5th 95th 5th 95th

51 10.5 5.0 16.0 51 10.5 5.1 15.8 51 10.6 4.9 16.3

52 13.0 7 .3 18.6 52 12.9 7.2 18.5 52 13.1 7.5 19.0

53 20.3 14.2 26.4 53 20.6 14. 3 2 6. 9 53 19.8 14.3 25.4

54 15.5 10.8 20.2 54 15.5 11 .3 19.7 54 15.5 1 0. 2 2 0. 9

55 27.5 20.5 34.4 55 27.7 20.5 35.0 55 27.2 2 0.5 33.8

81 8.6 3.1 13.4 81 8.3 3.6 13.1 81 8.1 2.6 13.6

82 14.3 7.7 20.8 82 14.6 7.6 21.5 82 13.9 7.9 19.8

83 20.4 14.5 26.4 83 20.9 14.8 27.0 83 19.8 14.4 25.284 1 6. 0 1 1. 1 2 0. 9 84 16.1 11.7 2 0.6 84 15.8 10.3 21.4

85 27.5 20.1 34.8 85 27.7 20.0 35.5 85 27.2 20.3 34.0

Females

Tooth FDI

Median

(Mths)

Percentile

Males

Tooth FDI

Median

(Mths)

PercentilePercentileMedian

(Mths)

Tooth

FDI

Total Sample (M+F)

Shaweesh AI, Bataineh OB, Alsoreeky E. Timing of Emergence of Deciduous Teeth in the Jordanian Population (unpublis hed)

This slide represent Data relating to

the Timing of emergence of

permanent teeth in Jordanian

population .

This is the Timing of

emergence of deciduous

teeth in Jordanians, and

the data are in months .


18/20

18

Sequence of emergence of permanent teeth in

Jordanians (Shaweesh, 2012A)

Rank Tooth Median age Rank Tooth Median age

Inter-arch

1 mand. 6 6.16

Maxillary

1 max. 6 6.27

1 max. 6 6.27 2 max. 1 7.18

1 mand. 1 6.40 3 max. 2 8.26

2 max. 1 7.18 4 max. 4 10.23

3 mand. 2 7.43 5 max. 5 11.17

4 max. 2 8.26 5 max. 3 11.30

5 max. 4 10.23 6 max. 7 12.44

5 mand. 3 10.23

Mandibular

1 mand. 6 6.16

5 mand. 4 10.32 1 mand. 1 6.40

6 max. 5 11.17 2 mand. 2 7.43

6 max. 3 11.30 3 mand. 3 10.23

6 mand. 5 11.44 3 mand. 4 10.32

7 mand. 7 11.90 4 mand. 5 11.44

8 max. 7 12.44 5 mand. 7 11.90

- Emergence of the tooth mean: surfacing - emerging to the surface andbecoming apparent.

- Eruption means: the full process of movement of the tooth .

Polymorphisms in sequence of permanent

tooth emergence (Shaweesh, 2012B)

Shawees h AI. Polymorphisms in sequence of permanent tooth emergence: a cross -sectional study on Jordanian children

and adolescents. Acta Odontologica Scandinavica 2012 Jan 3. [Epub ahead of print]

- Polymorphism :is the case where the teeth do not fallow the normal

order in eruption (abnormal eruption sequence) .

- Here we also have to memorize these data

Some examples to help you reading the schedule:

- What is the percentage of people who erupt 11 before 16 ? 5%-

- What is the percentage of people who erupt 13 before 15 Relating to

the FDI system ? 41 %

And so on.

This represents the Sequence of

emergence of permanent teeth in

Jordanians:

Here we have to memorize

arrangment of the eruption in the

intra-arch and inter-arch orders ,

and the Median age at which the

tooth erupt .

This slide represents the

Polymorphisms in

sequence of permanent

tooth emergence.


19/20

19

The Big 10 points for this Lecture

1- Chronology is the science of time and when we relate it to the teeth

development; it tells us the timing and the sequence for tooth development

and eruption.

2- Chronology is important in age estimation when the actual DOB is

unknown, in Forensic and in pediatric dentistry.

3- There are 3 stages for tooth eruption (in sequence):

1- Primary dentition stage: when all teeth are primary.

2- Mixed dentition stage: when theres some primary and other

permanent teeth.3- Permanent dentition stage: when only permanent teeth are present.

4- Order of eruption for both the deciduous and permanent dentition and

timing. (can be memorized easily from the tables that are provided in the

Doctors presentation)

5- On 3 years, we have a stage that is also calledThe functional

deciduous teeth stagebecause the deciduous dentitions are nowcomplete and in full occlusion.

6- Emergence as a word is better used than eruption; because emergence

describes the exact moment and stage of a tooth appearance in the mouth

while eruption describes the full movement process of a tooth.


20/20

20

7- Polymorphisms in emergence sequence: variations in the sequence of

the permanent teeth emergence in children and adolescents.

8- Some people have a reverse sequence. You need to know thepercentage of people who have this from the tables.

9- Times of developmental stages:

1- first evidence of calcification

2- Completion of crown

3- Occlusal contact with opposing tooth

4- Root completion

10- Approximately at age of 12 years ( 6 months) there will be no

deciduous teeth and the child will have a full permanent dentition.

(Permanent dentition stage, lasts for the rest of life)

Quote of the Day : The hero dont blame anyone but himself , he don't put excuses and thats

what make him a Hero .

Rmz Rabadi

Hadeel Sumrien Hebah Ramadnah

Russia ElShboulGhawanmeheel9A

Salam Ahmed Abeer M. Dirawi

Ahmed AlShamary Eman Idkaidek

Eman Nazzal Hibah Jarrah

Sawsan Z. Jwaied Noha Mohamad

Rawda Najjar GaYda'a Kana'an

SunDos Abu-zaid

P.S: We will not end this script without showing our appreciation to "Dalya

Mohamad" for providing us with her Recorder .

chronology of tooth development

Documents