Chronology of Human Dentition & Tooth Numbering System

8/12/2019 Chronology of Human Dentition & Tooth Numbering System

1/54

SUBMITTED TO: SUBMITTED BY:

DEPARTMENT OF PEDODONTIC NAVJOT KAUR

& PREVENTIVE DENTISTRY BDS IV PROF.

ROLL NO. 43


2/54

CHRONOLOGY DEFINITION:

Chronos - Time

Logos StudyIt is defined as the study which deals with the

timing of various stages of tooth development,starting with initiation of the first dental tissuelaid down to the emergence of the tooth into theoral cavity & its completion of calcification.


3/54

Originally it was based on the data of Logon &Kronfeld (1933).

Modified by:

Massler & Shour (1941),

Moorrees, fanning & hunt (1963),

Kraus & jordan (1965),Nystrom (1977).


4/54

TIMING OF CROWN & ROOT

DEVELOPMENTPRIMARY TEETH PERMANENT TEETH

Crown completion

Eruption

Root completion

Crown completion

Eruption

Root completion

Incisors

Canine &molars

4-6 months

6-12 months

1 year

3-4 years

3 years


5/54

NOLLA STAGES OF TOOTHDEVELOPMENT (1952)

Stage 0 : absence of crypt

Stage 0 : absence of crypt

Stage 1 : presence of crypt

Stage 2 : initial calcification

Stage 3 : 1/3rdof crown completed

Stage 4 : 2/3rdof crown completed

Stage 5 : crown almost completed

Stage 6 : crown completed

Stage 7 : 1/3rdof root completed

Stage 8 : 2/3rdof root completed

Stage 9 : root completed , apex open

Stage 10 : apical foraman closed


6/54

A

B

C

D

E

F

G

H


7/54

DECIDUOUS DENTITION Initiationof hard tissue development for all

deciduous teeth occurs between 3.5 & 4.5intrauterine months.

Crownget mineralized halfway by birth andbecome fully formed during first 12 month.

Roots are completed b/w the age of 1.5 & 3years.


8/54

TOOTH FIRST EVIDENCE OF

CALCIFICATION(weeks in utero)

CROWN

COMPLETED(months)

ERUPTION

(months)

ROOT

COMPLETED(years)

UPPER

A 14 1 10 (8-12) 1

B 16 2 11 (9-13) 2

C 17 9 19 (16-22) 3

D 15 6 16 (13-19) 2

E 19 11 29 (25-33) 3

LOWER

A 14 2 8 (6-10) 1B 16 3 13 (10-16) 1

C 17 9 20 (17-23) 3

D 15 5 16 (14-18) 2

E 18 10 27 (23-31) 3

CHRONOLOGY OF PRIMARY DENTITION


9/54


10/54

SEQUENCE OF ERUPTION OF

PRIMARY TEETH

AB D C E

A B D CE


11/54

PERMANENT DENTITION Mineralization of 1stpermanent molar commences

at birth & is followed by the other teeth during

first 3.5 years of postnatal life.

Crown completion takes place at an age of 7 years.

Mineralization ceases at an av. Age of 15-16 yearswith completion of roots of 2ndmolars.


12/54

Mineralization stages of 3rdmolar:

Initiation 9 years

Crown completion 13 years

Root formation 20 years

Development of central incisors is more rapid.

Development of canine & 2ndmolars the slowest.

Root development alone takes on an av. From 6-7

years.


13/54


14/54

TOOTH ERUPTION Derived from erumpere, meaning to break out.Axial or occlusal movement of tooth from its

developmental position within jaw to its functionalposition in the occlusal plane.

Eruption is only a part of physiological toothmovement.


15/54

TYPES OF ERUPTION3 types:

Continuously growing

Continuously extruding

Continuously invested teeth.


16/54

TYPES OF ERUPTION Continuously growing:

formation & eruption occurs throughout the life. formed from proliferative base.

Crown & roots are similar morphologically.

Extensive wear.

Eruption velocity increases whenever velocity ofwear increases.

E.g. incisors of rodent.


17/54

TYPES OF ERUPTION Continuously extruding:

Teeth stop forming once root formation is complete. Moderate occlusal wear.

Height is maintained by apical migration ofsurrounding epithelial attachment, without

simultaneous deposition of alveolar bone. Tooth eventually loosen & exfoliate completely.

E.g. cheek teeth of cattle & sheep.


18/54

TYPES OF ERUPTION Continuously invested teeth:

Similar to continuously extruding, but thealveolar bone remodels in response to eruption.

With normal attrition, the clinical crownshortens & tooth erupts to maintain vertical

height & occlusal function & bring the alveolarbone with it.

E.g. human teeth.


19/54

PHYSIOLOGICAL TOOTH

MOVEMENTConsist of :

a. Preeruptive tooth movement

b. Eruptive tooth movementc. Posteruptive tooth movement

PREERUPTIVE TOOTH


20/54

PREERUPTIVE TOOTHMOVEMENT

It is a movement positioning the tooth & its cryptwithin growing jaws preparatory to tooth eruption.

Change in the position of tooth germ is a result of

Body movement of tooth germ Growth of tooth germ

Relative change in position of associated deciduous andpermanent tooth germs

The permanent molars , which have no deciduouspredecessors, also exhibit movement.

All these movement occurs in association with growthof jaw .


21/54

ERUPTIVE TOOTH MOVEMENT

During this phase, tooth moves from its position within thebone of the jaw to its functional position in occlusion.

Principal direction of movement is occlusal or axial.

PREFUNCTIONAL TOOTH MOVEMENT movement oftooth after its appearance in the oral cavity till it attains thefunctional position.

Tooth erupts about 4 mm in 14 weeks.


22/54

POST ERUPTIVE TOOTH

MOVEMENT These are the movement that-

1. Maintain the position of an erupted tooth whilejaws continues to grow and

2. Compensate for occlusal and proximal wear.


23/54


24/54


25/54

MECHANISM OF TOOTH

MOVEMENT The mechanism that brings about tooth movement is

still debatable & is likely to be a combination of anumber of factors.

Main factors include Bone remodeling

Root growth

Vascular pressure

Ligament traction


26/54

THEORIES OF ERUPTIONBone growth theory

Root growth theory

Vascular pressure theoryPeriodontal ligament traction theory

Constriction of pulp

Pulp growth


27/54

BONE REMODELING THEORY

Selective deposition & resorption of bone bringsabout eruption.

It is important to permit tooth movement. Experiment establishes absolute requirement for

dental follicle to achieve bony remodeling & tootheruption.

It is the follicle that provide s the source of newbone forming cell & conduit for osteoclasts.


28/54

ROOT FORMATION THEORY

Proliferating root impinges on fixed case, thus convertingan apically directed force into occlusal movement.

Root formation follows crown formation and involves

cellular proliferation & formation of new tissue that mustbe accommodated by either movement of crown of thetooth or the resorption of bone at the base of socket.

Translation of the root growth into occlusal movement

requires fixed base .Advocates of this theory postulated the existence of

cushion hammock ligament , that provide fixed base


29/54

CONTRADICTIONS Cushion hammock ligament cannot act as fixed

base.

Some teeth move a distance greater than the rootlength & eruptive movement also occur aftercompletion of root formation.

Experimental resection preventing further root

formation does not stop eruptive tooth movement.


30/54

VASCULAR PRESSURE THEORYA local increase in the tissue fluid pressure in

periapical region is sufficient to move the tooth.

Teeth move in synchrony with arterial pulse, so local

volume changes can produce limited tooth movement. Factors in favour of this theory are-

Increase in hydrostatic pressure induced by hypotensivedrugs increases the rate of eruption while stimulation of

sympathetic nerves decreases rate of eruption. No. of capillaries increases with the eruption rate & their

distribution varies; more no. of capillaries are seen nearthe base of crypt than the alveolar crest.


31/54

PERIODONTAL LIGAMENT

TRACTION THEORY Cells & fibers of ligament pull the tooth into occlusal.

There is is good deal of evidences that the eruptiveforce resides in dental follicle- periodontal ligamentcomplex.

Abnormalities of dental follicle as shown in certaindiseases are associated with delayed tooth eruption.

Drugs that interrupt proper formation of collagen inligament also interfere with eruption.

PDL fibroblast have a ability to contract & transmitcontractile forces to extracellular environment.


32/54

Thus acc. to this theory, eruption of teeth

could be brought about by a combination of

events involving:Contractile forces by fibroblast

Transmitted to ECC & collagen

Tooth movement

Via fibronexuses

At appropriate inclination


33/54


34/54

MECHANISM OF POSTERUPTIVE

TOOTH MOVEMENT Mechanism of axial movement is similar to that of

eruptive tooth movement.

Mesial drift involves a combination of 2 separateforces resulting from occlusal contact of teeth &contraction of transseptal ligaments b/w teeth.

When jaws are clenched, bringing teeth into

contact, force is generated in a mesial directionbecause of summation of cuspal planes & becausemany teeth have a mesial inclination.


35/54

SHEDDING OF DECIDUOUS


36/54

SHEDDING OF DECIDUOUSTEETH

Physiological process resulting in elimination ofdeciduous dentition is called shedding orexfoliation.

Shedding is a result of progressive resorption of roots

of teeth & their supporting tissue , periodontalligament .

Pressure generated by the growing & eruptingpermanent tooth dictates the pattern of deciduous

tooth resorption.


37/54

First sign of root resorption is seen in deciduous CI &first molar by the age of 4-5 year.

In CI resorption starts on lingual side.

In molars from inner surfaces of root.

Resorption of deciduous incisors takes place morerapidly (1.5-2 yr) than that of canine & molars(2.5-5.7

yr.) .


38/54

Mechanism of shedding Pressure from the erupting successional tooth plays a

key role because the odontoclasts appear at predictedsites of pressure.

Unlike osteoblast, cementoblasts are not responsiveto hormone & cytokines. Therefore prior to resorptioncementoblastic layer has to be damaged probably byinflammatory process .

Reduced enamel ep. of erupting tooth release somesubstances to initiate this process.

Predentin resist resorption more than any other hardtissue.


39/54

Odontoclast

Attaches to hard tissue surfaces through clear zone

Sealed space lined by ruffled border

Microenvironment

Ruffled border act as proton pump

Acidify ECenvironment

Dissolution ofmineral

Secretion of lysosomal enzyme into sameenvironment

Degrade organicmatrix


40/54

FACTORS AFFECTING

SHEDDINGWhen a successional tooth germ is missing ,

shedding of the deciduous tooth is delayed .

Forces of mastication.


41/54

Clinical considerationsRemnants of deciduous teeth

Retained deciduous teeth

Submerged deciduous teeth


42/54


43/54

TOOTH NUMBERING SYSTEMVARIOUS NUMBERING SYSTEMS ARE:

Universal system

Symbolic systemFDI system


44/54


45/54

UNIVERSAL SYSTEM PERMANENT DENTITION: permanent teeth are numbered from

1-32.

The following universal notation designates the entire

permanent dentition:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17


46/54

ADVANTAGES OF UNIVERSAL

SYSTEM OF NOTATIONAcceptable to computer language.

Less confusing than palmer notation


47/54

SYMBOLIC SYSTEM It is also known as zsigmondy/palmer notation or

palmer notation system.

Introduced by adolph zsigmondy in 1861 & thenmodified for primary dentition in 1874.

Given by Palmerin 1870.


48/54

SYMBOLIC SYSTEM In this system arches are divided into quadrantswith the entire primary dentition being notated as :

E D C B A A B C D E

E D C B A A B C D E

e.g. max right central incisors- A|


49/54

SYMBOLIC SYSTEM PERMANENT DENTITION:

It is a four quadrant symbolic system, in which beginning

from central incisors , teeth are numbered 1 through 8.

8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8

8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8

E.g. right max 1stmolar6|


50/54

LIMITATIONS OF PALMER

NOTATIONSIt is generally incompatible with computer and word

processing systems.

More confusing.


51/54

FDI SYSTEM Proposed by Federation Dentaire

Internationale(FDI).

Adopted byWHO& other such as IADR.

It is atwo digit system given for both primary andpermanent dentition.


52/54

FDI system of tooth notation for

primary teeth 5- right max. quadrant

6- left max. quadrant

7- left mand. Quadrant 8- right mand. Quadrant

55 54 53 52 51 61 62 63 64 65

85 84 83 82 81 71 72 73 74 75


53/54

FDI notation for permanent teeth In this first digit indicate that is 1-4 & second digit

indicate tooth within the quadrant.

18 17 16 15 14 13 12 11 21 22 23 24 25 26 27 28

48 47 46 45 44 43 42 41 31 32 33 34 35 36 37 38


54/54

Thankyou

Chronology of Human Dentition & Tooth Numbering System

Documents

Transcript of Chronology of Human Dentition & Tooth Numbering System