Nomenclature, eruption and shedding of teeth.pptx

NOMENCLATURE, ERUPTION
AND SHEDDING OF TEETH
- Dr BERIN DHANYA N B
MDS- 1st year
Department Of Pediatric and Preventive Dentistry

CONTENTS
• Introduction
• Nomenclature
• Dental formulae-mammalian teeth
• Tooth numbering systems
a) Universal system
b) Zigmondy/Palmer system
c) FDI system
• Eruption
a) Pre- eruptive tooth movement
b) Eruptive/ pre functional tooth movement
c) Post – eruptive/ functional tooth movement
• Factors controlling eruption of teeth

• Theories of eruption
• Cellular and molecular events in eruption
• Clinical connsiderations
• Shedding of teeth
a) Definition.
b) Mechanism of shedding.
c) Pattern of shedding.
d) Histology of shedding.
e) Clinical consideration.
• References
• Conclusion

INTRODUCTION
 The first step in understanding dental anatomy is to know the nomenclature
or the system of names used to describe or classify the materials used in the
subject.
 Maxillary teeth:- teeth arranged in upper arch
 Mandibular teeth:- teeth arranged in lower arch

NOMENCLATURE
 Dentition:- In human 2 dentitions are present
1. Deciduous(Primary)
2. Permanent(Succedaneous)
 The primary term refers to “constituting or belonging to the first stage of process”
 Primary teeth means milk teeth defined as “one of the temporary teeth of
mammals that are replaced by permanent teeth” is also called baby teeth
 Transitional phase when both primary and permanent teeth are present is called as
Mixed dentition period.
 The Succedaneous can be used to describe a successor dentition that is the
permanent teeth that replace primary teeth
WHEELERS’S DENTAL ANATOMY, PHYSIOLOGY AND OCCLUSION – STANTLEY J NELSON

FORMULAE FOR MAMMALIAN TEETH
o The denomination and a number of all mammalian teeth are expressed by
formulae that are used to differentiate the human dentition from other species.
o Each tooth is represented by a Initial letter
 I for Incisor
 C for Canine
 P for Premolar
 M for Molars
o The formulae includes only one side of maxilla and mandible

DENTAL FORMULAE-MAMMALIAN TEETH
FOR PRIMARY TEETH
FOR PERMANENT HUMAN DENTITION

• The universal system
• Zsigmondy/Palmer system
• Federation Dentaire internationale (FDI)
system
TOOTH NUMBERING SYSTEMS

UNIVERSAL SYSTEM
• Notation for primary dentition uses uppercase letters
• The ADA in 1968 officially recommended the “universal numbering system”
• For Primary Dentition:
 For Maxillary teeth
Beginning with right maxillary second molar,
Letters A  J
 For Mandibular teeth
Beginning with left mandibular second molar,
Letters K  T

• For Primary Dentition
• For permanent dentition:
 Maxillary teeth from Maxillary right third molar have numbers beginning as 1  16.
 Beginning with Mandibular left third molar the teeth are numbered as 17  32

Advantages of Universal Numbering System
• Concept is very simple
• Each tooth has a unique numerical or an alphabetical Code.
• Left and right teeth of same type have different designations.
• For example, permanent right maxillary 1st molar is ‘3’ while
permanent left maxillary 1st molar is ‘14’.
• It can be communicated verbally.
• It is compatible with computer keyboard and easy for typing.
Limitations
• Difficult to memorize notations
• Difficult to visualize graphically.
Textbook of Oral Anatomy, Histology, Physiology and Tooth Morphology

 Oldest method and the most popular system of the twentieth century.
 The symbolic notation system was originally termed the Zsigmondy
system after the Hungarian (Vienna) dentist Adolf Zsigmondy, who
developed the idea in 1861, using a Zsigmondy cross grid to record
quadrants of tooth positions
 The numbers/letters indicate the position of the tooth from the
midline.
Zsigmondy/Palmer notation system

• In this system, the arches are divided into quadrants
• For primary dentition:
• For permanent dentition:

Advantages
• Any anomalies like tooth transposition, edentulous spaces, can be easily
represented using Zsigmondy cross .
• It is simple to follow and user friendly.
• Quadrant symbols are same for both the dentitions.
Limitations
• It is incompatible with computers and word processing systems as it is
difficult to create the symbol using standard keyboard.
• It is not possible to verbally pronounce the tooth designation 1┘. if one
has to communicate ‘permanent maxillary right central incisor.
• Though the method is simple, there are more chances of error while
designating the side of the tooth.

FDI system
• FDI – A two digit system proposed by Federation Dentaire
Internationale for both primary and permanent dentitions has been
adopted by World health Organization and accepted by International
Association for Dental Research
• The two digit system proposed by FDI, has a unique number for each
tooth in the system for both primary and permanent dentition

For primary dentition:
For permanent dentition:

 Eruption, a Latinized term ‘erumpere’ meaning “to break out
 The axial & occlusal movement of the tooth from its developmental position
in the jaw to the functional position in the occlusal plane - ORBANS
ERUPTION OF TEETH
ORBAN’S ORAL HISTOLOGY AND EMBRYOLOGY – 13th EDITION

STAGES OF TOOTH ERUPTION
PRE- ERUPTIVE TOOTH MOVEMENT
ERUPTIVE/ PRE FUNCTIONAL TOOTH
MOVEMENT
POST – ERUPTIVE/ FUNCTIONAL TOOTH
MOVEMENT

PRE-ERUPTIVE MOVEMENT
• When primary tooth germ first differentiate, they are extremely
small and a good deal of space is available for them in the developing jaw.
• This space is soon used because of rapid growth of tooth germ and
crowding results, especially in the incisor & canine region.
• This crowding is relieved by growth of jaws in length. Bony
remodeling of crypt wall occurs to facilitate movements of
growing tooth germ and movement.

a. Total Bodily Movement – which occurs continuously as the jaw grows, is the
movement of the entire tooth germ. This causes bone resorption in the direction of the tooth
movement and bone deposition behind it.
b. Eccentric Growth – Relative growth in one point of the tooth where rest of the tooth
remains constant. Eg – The root elongates, yet the crown does not increase in size. The
crown maintains a constant relationship to the surrounding alveolar bone while increasing
in alveolar height compensates for the root growth

HISTOLOGIC CHANGES
Selective deposition and removal of bone by
osteoblastic and osteoclastic activity
Remodeling of the bony wall of the crypt
Drifting or growth of the tooth germ

ERUPTIVE TOOTH MOVEMENT
•The axial or occlusal movement of the tooth from its developmental
position within the jaw to its functional position in occlusal plane
•The actual eruption of the tooth, when it breaks through the gum is only
one phase of eruption
• The term ‘pre-functional’ eruptive tooth movement is used to describe
the movement of the tooth after its appearance in the oral cavity till it
attains the functional position.

The prefunctional eruptive phase starts with the initiation of root formation and
ends when the teeth reach occlusal contact
Four major events occur during this phase:
ROOT FORMATION
MOVEMENT
PENETRATION
INTRAORAL OCCLUSAL OR INCISAL
MOVEMENT
ESSENTIALS OF ORAL HISTOLOGY AND EMBRYOLOGY A CLINICALAPPROACH – JAMES K AVERY AND DANIEL J
CHIEGO – 3RD EDITION

ROOT FORMATION
proliferation of
the epithelial root
sheath
initiation of root
dentin and
formation of the
pulp tissues of the
forming root
Root formation
also causes an
increase in the
fibrous tissue of
the surrounding
dental follicle

MOVEMENT
A reduced epithelial layer overlying the erupting crown arises from the
reduced enamel epithelium
Both of these epithelial layers proliferate toward each other, their cells
intermingle, and fusion occurs.
The reduced enamel epithelium next contacts and fuses with the oral
epithelium
The movement is the result of a need for space in which the enlarging roots
can form
Movement occurs incisally or occlusally through the bony crypt of the jaws to
reach the oral mucosa.
ESSENTIALS OF ORAL HISTOLOGY AND EMBRYOLOGY A CLINICALAPPROACH – JAMES K AVERY

PENETRATION
Penetration of the tooth’s
crown tip through the fused
epithelial layers allows
entrance of the crown
enamel into the oral cavity.
Only the organic
developmental cuticle
(primary), secreted earlier
by the ameloblasts, covers
the enamel

INTRAORAL OCCLUSAL OR INCISAL MOVEMENT
Intraoral occlusal or incisal
movement of the erupting
tooth continues until
clinical contact with the
opposing crown occurs
The crown continues to
move through the mucosa,
causing gradual exposure
of the crown surface, with
an increasingly apical shift
of the gingival attachment

The prefunctional eruptive phase is characterized by
 Changes in the tissues overlying the erupting teeth
 Changes in the tissues surrounding the erupting teeth
 Changes in the tissues underlying the erupting teeth
CHANGES IN TISSUES
ESSENTIALS OF ORAL HISTOLOGY AND EMBRYOLOGY A CLINICALAPPROACH – JAMES K AVERY

CHANGES IN THE TISSUES OVERLYING THE ERUPTING TEETH
The dental follicle changes and forms a pathway for the erupting teeth
A zone of degenerating connective tissue fibers and
cells immediately overlying the teeth appears first
During the process, the blood vessels decrease in
number, and nerve fibers break up into pieces and degenerate
The altered tissue area overlying the teeth becomes visible as
an inverted triangular area known as the eruption pathway

•Prior to clinical emergence of crown there is alteration of the connective tissue of
dental follicle to form a pathway for erupting tooth
• The fibro cellular follicle surrounding a successional tooth retains its connections with
the lamina propria of the oral mucous membrane by means of strand of fibrous tissue
containing remnants of the dental lamina known as GUBERNACULAR CANALS.
HISTOLOGIC CHANGES

The connective tissue mass- gubernacular cord- acts as guiding plane
As the deciduous teeth erupts, the permanent tooth germ becomes situated
apically & is entirely enclosed by bone except for gubernacular canal
Loss of bone and soft connective tissue between the REE and overlying
oral epithelium
REE and oral epithelium begin to proliferate and migrate into the
disorganized connective tissue
The central cells of this epithelial mass degenerate and form an epithelium
lined canal through which the tooth erupts without hemorrhage.

CHANGES IN THE TISSUES SURROUNDINGTHE ERUPTING TEETH
With the tooth eruption, the alveolar bone crypt increases in height to
accommodate the forming root
Special fibroblasts have been found in the periodontium around the erupting
teeth. These fibroblasts have
contractile properties.
During eruption, collagen fiber formation and fiber turnover are rapid,
occurring within 24 hours.
Gradually the fibers organize and increase in number and density as the tooth
erupts into the oral cavity.
Blood vessels then become more dominant in the developing ligament and
exert additional pressure on the erupting tooth

CHANGES IN THE TISSUES UNDERLYING THE ERUPTING TEETH
As the crown of a tooth begins to erupt, it gradually moves occlusally,
providing space underlying the tooth for the root to lengthen
Fibroblasts appear in great numbers in the fundic area, and some of these
fibers form strands that mature into calcified trabeculae.
These trabeculae form a network, or bony ladder, at the tooth apex. This is
believed to fill the space left behind as the tooth begins eruptive movement
Dense bone then forms around the tooth’s apex, and bundles of fibers attach to
the apical cementum and extend to the adjacent alveolar bone to provide more
support.

POST ERUPTIVE PHASE (Functional Tooth Movement)
Post eruptive tooth movements are those that
a. Maintain the position of the erupted tooth while the jaw continues to
grow.
b. Compensate for occlusal and proximal wear
They are divided into three categories –
1. Movements to accommodate the growing jaws
2. Those to compensate for continued occlusal wear
3. Those to accommodate interproximal wear

a. Accommodation for growth of Jaw:
1. Mostly occurs between 14 and 18 years by formation of new bone at the
alveolar crest and base of the socket to keep pace with increasing height of jaws,
and the apices of the teeth move 2 to 3 mm away from the inferior dental canal.
b. Compensation for Occlusal Wear:
1. It is achieved by continued cementum deposition around the apex of the tooth.
However this deposition occurs only after tooth moves.
c. Accommodation for inter proximal wear:
1. Proximal wear occur at contact points between the tooth which can decrease the
arch length by as much 7 mm in the mandible.
Compensated by mesial or approximal drift
Pediatric Dentistry- A Clinical Approach- Goran Koch

ESSENTIALS OF ORAL HISTOLOGY AND EMBRYOLOGY A CLINICALAPPROACH – JAMES K AVERY AND DANIEL J
CHIEGO – 3RD EDITION
To Summarize:

NOLLA’S STAGES OF TOOTH ERUPTION

FACTORS CONTROLLING ERUPTION OF TEETH
R Almonaitiene, I Balciuniene, J Tutkuviene, Factors influencing permanent teeth eruption. Stomatologija, Baltic
Dental and Maxillofacial Journal, 2010 ;12: 67-72
• Genetics
• Gender
• Nutrition
• Pre term birth
• Socioeconomic factors
• Body weight and height
• Craniofacial morphology

GENETICS-
• There are certain genetic disorders that affect teeth eruption. Most of
them are reported to delay permanent teeth eruption, others are
associated with complete failure of teeth to erupt.
• Genetic disorders can be divided into disorders:-
• That affect enamel formation/ tooth follicle. Eg; amelogenesis
imperfecta, hurler syndrome, mucopolysacharidosis
• That interfere with osteoclastic activity. Eg; cledocranial dysplasia,
osteopetrosis
NUTRITION –
Chronic malnutrition extending beyond early childhood is
correlated with delayed teeth eruption

GENDER:
Teeth emergence in girls is more rapid than in boys. The
difference between eruption time is 4-6 months.
Early eruption of permanent teeth in females is attributed to
earlier onset of maturation.
In girls the maxillary canine can be erupted before the second
premolar, and the mandibular second premolar can be
expected before second molar, in boys both the orders are
reversed.

PRE-TERM BIRTH-
• According to WHO preterm birth is defined as birth occurring before
37 weeks of gestation or if the birth weight is below 2500g.
• Most of the studies reported that Preterm children have delayed
primary and permanent teeth eruption.
SOCIOECONOMIC FACTORS-
• Children from higher socioeconomic background shows earlier tooth
emergence than children from lower socioeconomic class.
• It is thought that higher socioeconomic child get better health care,
nutrition and these influence earlier development of dentition

BODY WEIGHT AND HEIGHT-
Taller and heavier children are slightly advanced dentally while it is apparent that
stunting is more strongly associated with delayed tooth eruption.
Reasearch show that obese children mature earlier and teeth tend to erupt on an
average 1 to 1.5 year earlier as compare to children with normal body mass index.
CRANIOFACIAL MORPHOLOGY
 Studies shows that the maxillary second molar may erupt earlier in patients
with skeletal maxillary class II malocclusion.
 Studies suggest that eruption of maxillary teeth especially molars are delayed
in skeletal class III.
 Skeletal open bite is associated with advanced dental maturity if compared to
skeletal deep bite.

Massler M, Schour I. Studies in tooth development: theories of eruption. American Journal of Orthodontics
and Oral Surgery. 1941 Oct 1;27(10):552-76.
TO SUMMARIZE:

THEORIES OF TOOTH ERUPTION
The most accepted theories of tooth eruption are:
Bone remodelling theory
Root formation theory
Vascular pressure theory
Periodontal ligament traction theory
Dental Follicle theory

BONE REMODELLING THEORY (BRASH, 1928)
• It is clearly important to permit tooth movement.
• If the tooth germ is removed experimentally and the
dental follicle left intact, an eruptive pathway forms in the overlying bone.
• If silica replica is substituted for the tooth germ it also erupts.
• If the dental follicle is removed no eruptive pathway forms.
• It is the follicle that provides the source for new bone formation cells and conduit
for Osteoclast designed from monocytes through its vascular supply.
• It is proposed that the osteoblast under hormonal influence secretes collagenase and
other proteolytic enzymes to remove the osteoid layer.
• In so doing these cells round up and expose newly denuded mineralized bone
surface, providing the stimulus to attract osteoclast to the site.
Massler M, Schour I. Studies in tooth development: theories of eruption. American
Journal of Orthodontics and Oral Surgery. 1941 Oct 1;27(10):552-76.

Evidence in Support :Bone remodeling
occurs around developing tooth Germ Bone
forms when tooth germ is replaced by a
silicone model that later erupts
Evidence Against : Bone
remodeling—cause or effect—
debatable

ROOT FORMATION THEORY
• Mechanism of eruption would be that the crowns of the teeth are
pushed into oral cavity by virtue of the growth and elongation of
their roots
• Root formation follows crown formation & involves cellular
proliferation and formation of new tissue that must be accommodated
by either movement of the crown or resorption of bone at the base
of the socket.
(MASSLER AND SCHOUR-1941)

EVIDENCE IN SUPPORT
• If crown movement is
prevented bone
resorption occurs at the
base Growth of root
impinges on a fixed
base—cushion-hammock
ligament that translates
apical force to eruptive
force
EVIDENCE AGAINST
• Cushion-hammock
ligament is a membrane
and has no bony
insertion, so cannot act
as a fixed base to
translate apical force to
occlusal force
• Eruptive distances are
greater than length of the
root
• Rootless teeth also erupt
rarely

VASCULAR PRESSURE/ HYDROSTATIC PRESSURE THEORY -
Sutton and Graze, 1985
The local increase in tissue fluid pressure in the periapical
region cause the occlusal movement
Teeth move in synchrony with the arterial pulse so local
volume change can produce limited tooth movement
Ground substance swells up to 50 % with addition of water
and this differential pressure causes the tooth movement
between the tissues below and above an erupting tooth.
(MASSLER AND SCHOUR-
1941)

Massler M, Schour I. Studies in tooth development: theories of eruption. American Journal of Orthodontics and
Oral Surgery. 1941 Oct 1;27(10):552-76.
• Submerged teeth erupt under the influence of hyperemia induced by
mechanical irritation.(dentures and finger rubbing)
• Hyperemia in periodontitis causes supra eruption of tooth.
• In hypopituitarism and hypothyroidism eruption is markedly retarded
concomitant with reduced vascularity of periodontal tissues. In
hyperpituitarism , eruption is accelerated and vascularity of periodontal
tissues increased.
• Removal of vasoconstrictor nerve causes accelerated eruption
concomitant with increased vascularity of periodontal tissues.
• Though vascular pressure can play an important role by generating
an eruptive force, opinion differ whether these pressure are primarily
responsible for eruption.

Evidence Against: Experimental root
resection and insertion of metallic barrier
to cut off apical hydrostatic pressure, no
change in eruption rate Injection of
lignocaine with or without
vasoconstrictor adrenaline to cause
decreased hydrostatic pressure, results in
increase in eruption rate
Evidence in Support: Increase in apical
hydrostatic pressureby hypotensive drugs
increases eruption rate Sympathetic nerve
stimulation causes vasoconstriction,
thereby decreases apical hydrostatic
pressure—eruption rate decreased

PERIODONTAL LIGAMENT TRACTION THEORY
(Berkovitz and Thomas, 1969)
•Contractile force created by the cells and fibers of the PDL is helping in
pulling the tooth into the occlusion.
• Two mechanisms
1. Collagen constriction
2. Constriction due to fibroblast
• Eruptive movement is brought about by a combination of events involving a
force initiated by the fibroblasts
• This force is transmitted to the extra cellular compartment via fibronexuses
and to collagen fiber bundles which aligned in an appropriate inclination
brought about root formation and bring about tooth movement. These fiber
bundles must have the ability to remodel for eruption to continue, & interfere
with this ability affect the process .

EVIDENCE IN SUPPORT
• Experimental root resection and metallic barrier
insertion—distal fragment erupts due to attachment of
dental follicle
• Diseases affecting dental follicle delay eruption
• Drugs interfering with collagen fibers formation delays
eruption
• Tissue culture experiment—fibroblast of dental follicle
contracts collagen gel-contractile force summation leads
to eruptive force
EVIDENCE AGAINST
• Periodontal ligament fibroblast not attached to
bone or not properly oriented for eruption in
preeruptive phase
• Existence of fibronexus and contractile ability of
fibroblasts disputed

DENTAL FOLLICLE THEORY
Rabea AA. Recent advances in understanding theories of eruption. Future Dental Journal. 2018 Dec 1;4(2):189-96.
The follicular theory postulates that the dental follicle is capable of inducing,
bone resorption above the developing crown and bone apposition below it.
This enables the formation of an eruptive path to occur through which the
tooth will be passively conducted .
In osteopetrotic animal, which lack a factor that stimulates differentiation of
osteoclasts, eruption is prevented, because no mechanism for bone removal
exists
However, local administration of this factor, colony-stimulating factor 1 (CSF-
1), permits the differentiation of osteoclasts and eruption occurs

Recently molecular studies have revealed that eruption is regulated
by inductive signals between the dental follicle, reduced enamel
epithelium (REE), stellate reticulum and alveolar bone .Regional
differences in the dental follicle were described .
It is suggested that the coronal aspect of the dental follicle regulates
osteoclastogenesis(bone resorption) and the basal aspect of the dental
follicle regulates osteogenesis (bone formation) .
The receptor activator of nuclear factor kappa B ligand (RANKL)
gene is a marker gene for bone resorption. Bone morphogenetic
protein-2(BMP-2) gene is a marker for bone formation.

RECENT THEORIES OF ERUPTION
• This theory postulates that follicular soft tissues detect bite-forces so direct bone
remodeling with the effect of enabling tooth eruption
Bite forces sensed by soft tissue dental follicles
theory
• This theory postulates that the root membrane acts as a glandular membrane. So, the
innervation in this membrane causes pressure in the apical part of the tooth which
results in tooth eruption
Innervation-provoked pressure theory
• After the functional plane is reached, the eruption of the tooth is balanced in
response to the growth of the vertical growth of the mandible
The equilibrium theory
• The synchronized forces of the orofacial muscles, under the control of the central
nervous system, are responsible for the active movements of a tooth and the
molecular events prepared a pathway under the control of these forces
Neuromuscular theory or unification theory

CELLULAR AND MOLECULAR EVENTS IN ERUPTION
• The recruitment of the mononuclear cells to the dental follicle.
• Its differentiation into Osteoclast and their activation.
• Bone resorption at the coronal half of the dental follicle.
• Bone formation at the basal end.
• The dental follicle serves not only as target tissues for
mononuclear cells but also to regulate cellular events of eruption.
• Eruption is a localized genetically programmed event.
• The regulatory gene that encode expression of various transcription
factors are complex and involve series of signaling interactions
between dental follicle and cells of the bony crypt, namely
Osteoclast and Osteoblast

CLINICAL CONSIDERATIONS
• Variation in scheduled time of eruption
1. Delayed or retarded eruption
2. Premature eruption
a) Natal teeth
• Impaction of teeth
• Failure of eruption
• Hypereuption
• Teething
• Eruption cyst
• Eruption sequestrum
• Ectopic eruption

NATALAND NEONATAL TEETH
• Natal Teeth- Teeth that are present birth.
• Neonatal Teeth - Teeth erupting prematurely in the first 30 days of life.
TEETH AFFECTED ARE:-
• Usually deciduous mandibular central incisors.
Etiology:-
• Cause of premature eruption can be hypovitaminosis, hormonal
stimulation, trauma, febrile state and syphilis.
•They have also found to be associated with multisystem syndrome and
developmental abnormalities providing the evidence of genetic
contribution.
Dentistry for the Child & Adolescent- McDonald

Clinical Apperance:-
• Natal and Neonatal teeth may resemble normal primary teeth,
but they are poorly developed, small conial, yellowish with white
hypoplastic enamel and dentin and with poor or total failure of
development of roots.

MANAGEMENT:-
• A radiograph must be made to determine the amount of tooth development and
relationship of prematurely erupted tooth to its adjacent teeth.
•The waiting period before performing tooth extraction is to allow for the
commensal flora of the intestine to become established and to produce vitamin
K, which is essential for the production of prothrombin in the liver.
• It is safer to wait until a child is 10 days old before extracting the tooth.
•If it is not possible to wait, then it is advisable to evaluate the need for
administration of vitamin K with help of pediatrician.
•The preferential approach is to leave the tooth in place & to explain to the
parents the desirability of maintaining this tooth in the mouth.
Rao RS, Mathad SV. Natal teeth: Case report and review of literature. Journal of Oral and Maxillo Facial Pathology.
Vol. 13 Issue 1 Jan - Jun 2009

DELAYED ERUPTION
Children with chronic disease- shows delay in both physical &
dental development.
Etiology:-
Physical obstruction
Endocrinopathies- Hypopituitarism
Hypothyroidism
Hypoparathyrodism
Syndromes – Down syndrome
Cleidocranial dysplasia
Tricho dento osseous syndrome
Pycnodysostosis

L Suri,E Gagari,H Vastardis, Delayed tooth eruption: Pathogenesis, diagnosis, and treatment. A literature review,Am J
Orthod Dentofacial Orthop 2004;126:432-45

TEETHING
• The moment a tooth breaks through the oral epithelium, an acute
inflammatory response occurs in the connective tissue adjacent to the tooth.
• This is often associated with pain, slight fever, and general malaise, all
signs of an inflammatory process. In infants these symptoms are popularly
called “teething.”

LOCAL FEATURES
• Redness or swelling of the
gingiva over erupting tooth
• Patches of erythema on
cheeks.
• Flushing of the skin of the
adjacent cheek.
• Hand and fingers always in
the mouth.
• Increased salivation and
drooling
SYSTEMIC FEATURES
• General irritability and crying
• Increased temperature
• Loss of appetite
• Sleeplessness
• Increased thirst
• Circumoral rash
• Bowel upset

• Management
Teething toys – wide variety of teething ring, solid silicone based teething
rings, keys.
• Topical Medicaments
• Salicylates which combine local counter
irritant and anti inflammatory properties with
analgesic and antipyretic effect.
Antiseptics -which control infection at the
site of tooth eruption
Local analgesics- which provide rapid but
short lived pain relief

ERUPTION CYST
• A bluish purple elevated area of tissue
• blood filled cyst.
• occasionally develops few weeks before eruption of primary/permanent
dentition.
• results due to trauma to soft tissue during function.
• Subsides after eruption of teeth.
• common area; primary 2nd molar or permanent 1st molar region.
Mangement:
Usually tooth breaks thru the tissue within a few days and hematoma
subsides, besides the condition is self limiting

ERUPTION SEQUESTRUM
• Tiny irregular spicule of bone overlying the crown of an erupting
permanent molar, found just prior to or immediately following the
emergence of the cusp tips through oral mucosa.
• It directly overlies central occlusal fossa but is contained within soft tissue
Etiology:- As molar teeth erupt thru the bone, they will occasionally separate a
small osseous fragment from the surrounding contiguous bone, much in
crockscrew fashion.
Clinical Significance and treatment:-
• Child may complain of slight soreness in the area, probably by
compression of the soft tissue over the spicule during eating or just prior to
breaking thru mucosa.
• No treatment is necessary as the condition corrects itself.
SHAFERS TEXTBOOK OF ORAL PATHOLOGY

ECTOPIC ERUPTION
• Abnormal eruption patterns - due to arch length inadequacy or a variety of local
factors (supernumerary teeth, congenital absence or malformation of permanent,
necrosis or dystrophic calcification of primary and ankylosis).
• In crowded arch- max 1st molar impacted by distal prominence of primary 2nd
molar. Primary molar will resorb at distal root surface, permanent get stuck &
eruption stops.
• Reversible – Molar frees itself from the ectopic position and erupts into normal
alignment with 2nd primary molar in position(7 yrs).
• No corrective treatment required.

• Irreversible- remains unerupted & in contact with cervical root area of 2nd
primary molar.
• Lead to premature loss of primary molar.
• If detected at 5-6 yrs of age- watchful waiting for self correction.
• Intervention is indicated if age group is >7 yrs or opposing molar reaches
the occlusal plane.
• Interceptive correction involves guidance of the ectopic molar into
normal position, retention of favourable eruption sequence, maintenance
of arch length.
• Treatment option require the use of distally directed forces from 2nd
primary molars to disengage and allow eruption of the 1st permanent molar.

Ectopically erupted canine- 2%
• Always palpate buccally and
palatally for canine.
• Treatment- extraction of
primary canine.
• Severe case- surgical exposure
of canine and fixed appliance.

Ectopically labial late eruption of max central incisor
• It is due to early trauma, odontoma, supernumerary teeth.
• After surgical exposure the incisor often erupts unaided &
will end up in the right position & with reinserted mucosa.

SHEDDING OF TEETH
DEFINITION:-
The physiological process resulting in the elimination of
deciduous dentition is called as shedding.
Causes of shedding-
Pressure resulting from growing and erupting permanent teeth
induces the differentiation of odontoclasts which results in resorption
of primary roots.
Increased masticatory forces on the weakened teeth due to increased
muscular growth.

• The shedding of primary teeth is the result of progressive
resorption of the roots of teeth and their supporting tissue,
the periodontal ligament.
• Pressure generated by the growing and erupting permanent
tooth dictates the pattern of primary tooth resorption. At first
this pressure is directed against the root surface of the primary
tooth itself.
PATTERN OF SHEDDING:

• Because of the developmental position of the
permanent incisor and canine tooth germ and their
subsequent physiologic movement in an occlusal and
vestibular direction,
• Permanent mandibular incisors erupt lingual to the still
functioning deciduous teeth.
Resorption of the roots of
the primary incisors and
canine begins on their
lingual surface
• early developing bicuspid are found in between
them.
Resorption of the roots of
primary molars begins
on their inner surface
• Continued growth of the jaws and occlusal movement
of primary molars
• This change in position provides the growing bicuspid
with adequate space for their continued development
the Successional tooth
germ come apical to the
deciduous molars
• Resorption of the deciduous molars is again initiated
and this time continues until the roots are completely
lost and tooth is shed.
When bicuspids begins to
erupt

• Resorption of dental hard tissue is achieved by cells with
histologic nature similar to osteoclast , known as
odontoclast.
• Odontoclasts are resorbing cells derived from monocytes &
migrate from blood vessels to resorption site , where they
form multinucleated odontoclast with a clear attachment
zone & ruffled border.
• Giant multinuclear cells with 4-20 nuclei
• Resorption occurs at ruffled border which greatly increases
surface area of odontoclast in contact with bone.
HISTOLOGY OF SHEDDING

• Distribution of odontoclast during tooth resorption found on surface
of roots in relation to advancing permanent tooth.
• Single rooted tooth shed before root resorption is completed.
• Odontoclasts are not found in pulp chamber of these teeth.
• In molars, roots are completely resorbed & crown is partially
resorbed.
• Odontoblasts layer is replaced by odontoclasts.
• Sometimes all dentine is removed & vascular tissue is seen beneath
translucent cap of enamel.

• Odontoclast release hydrolytic enzymes onto the resorption lacunae
or the lysosomes for the degradation of collagenous and non
collagenous organic matrices.
• They mineralize apatite crystals of the dental hard tissue by means
of H+-ATPase & subsequently they degrade dentin proteins by
action of Cathepsin K and MMP-9.
• At the end of resorption they loose their ruffled border and became
detached from the resorbed surface.

CLINICAL SIGNIFICANCE OF SHEDDDING
a) Remnants of deciduous teeth
• Sometimes parts of the roots of deciduous teeth are not in the
path of erupting teeth and may escape resorption.
• Such remnants consisting of dentin and cementum may
remain embedded in the jaw for considerable time.
• Most frequently found in region of lower second premolars .
• Progressive resorption of the root remnants and replacement
by bone may cause the disappearance of remnants.

b) Retained deciduous teeth
• Deciduous teeth retained for a long time beyond their usual shedding schedule.
• Such teeth are usually without permanent successor or their successors are
impacted.
• Retained deciduous teeth are most often lateral incisor, less frequently second
permanent premolar in mandible.
• If permanent tooth is ankylosed or impacted, its deciduous predecessors may
also be retained, seen in case of deciduous and permanent canine.

c) Submerged primary teeth
• Trauma may result in damage to either dental follicle or the developing
periodontal ligament.
• If this happens, the eruption of the tooth ceases, & it becomes ankylosed
to the bone of the jaw.
• Because of continued eruption of neighbouring teeth and increase in
height of alveolar bone, the ankylosed tooth may be either “shortened”
or submerged in alveolar bone.
• Submerged primary teeth prevent the eruption of permanent successor or
force them from their position.
• Submerged primary teeth should therefore be removed as soon as
possible.

Premature exfoliation of teeth
Metabolic disorders
• Facial hemihypertrophy
• Acatalasia /Takahara’s disease
• Chediak –Higashi Syndrome
• Hypophosphatasia
• Pappilon –lefevre syndrome
• neutropenia
• Malignancies –
• Langherhans cell histiocytosis
• lettere siwe disease

CONCLUSION
• For the clinician to treat dental problems knowledge of
proper eruption time and shedding time is very important.
• A variety of developmental defects that are evident after
eruption of the primary & permanent teeth can be related
to local and systemic factors.

REFERENCES
• Wheelers’s Dental Anatomy, Physiology And Occlusion – Stantley J Nelson
• Orban’s Oral Histology And Embryology – 13th Edition
• Essentials Of Oral Histology And Embryology A Clinical Approach – James
K Avery And Daniel J Chiego – 3rd Edition
• Pediatric Dentistry- A Clinical Approach- Goran Koch, Sven Paulsen.
• Shafers Textbook Of Oral Pathology
• Dentistry For The Child & Adolescent- Mcdonald
• Textbook Of Oral Anatomy, Histology, Physiology And Tooth Morphology
• Tencates Oral Histology, Development, Structure And Function- 8th Edition

• Massler M, Schour I. Studies in tooth development: theories of eruption.
American Journal of Orthodontics and Oral Surgery. 1941 Oct
1;27(10):552-76.
• Thimmegowda U, Amrutha B, et al.Applicability of new proposed novel
tooth numbering system for primary teeth: An observational study. J Indian
Soc Pedod Prev Dent 2021;39:373-8.
• Rabea AA. Recent advances in understanding theories of eruption. Future
Dental Journal. 2018 Dec 1;4(2):189-96.
• Rao RS, Mathad SV. Natal teeth: Case report and review of literature.
Journal of Oral and Maxillo Facial Pathology. Vol. 13 Issue 1 Jan - Jun
2009

• L Suri,E Gagari,H Vastardis, Delayed tooth eruption: Pathogenesis,
diagnosis, and treatment. A literature review,Am J Orthod Dentofacial
Orthop 2004;126:432-45
• R Almonaitiene, I Balciuniene, J Tutkuviene, Factors influencing
permanent teeth eruption. Stomatologija, Baltic Dental and
Maxillofacial Journal, 2010 ;12: 67-72

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