DEVELOPMENTAL DISTURBANCES IN SHAPE AND SIZE AND NUMBER OF TEETH

Presented byDr. Amitha G

Dept Of Oral and maxillofacial pathology

1. Size2. Shape/Form3. Number 4. Defects in structure involving

Enamel and Dentin

Developmental Disturbances effects teeth in

Contents Development disturbance of teeth:1. Size 1. Microdontia 2. Macrodontia

2. Shape GerminationFusionConcrescenceDilacerationTalon cuspDens of denteDense evaginatusTaurodontiumSupernumerary roots

3. Number AnodontiaSupernumeraryImpaction

1. Microdontia

(1) True Generalized Microdontia

(2) Relative Generalized Microdontia

(3) Focal or Localized Microdontia

Size

• All teeth are smaller than normal

• Teeth are well formed • Occur in some cases

of pituitary dwarfism• Exceedingly rare

(1) True Generalized Microdontia

• Normal or slightly smaller than normal teeth • Present in jaws that are somewhat larger than

normal• It’s a illusion of true microdontia• Role of hereditary factors produce such a

condition.• The person may inherit the jaw size from one

parent and teeth size from the other parent.

(2) Relative Generalized Microdontia

• Common condition• Affects maxillary lateral incisior and 3rd molar• Often congenitally missing Common forms of localized microdontia is that which affects

maxillary lateral incisior

‘Peg lateral’Instead of parallel or diverging mesial and distal surfacesSides converge or taper together incisallyForms cone-shaped crownRoot is frequently shorter than usual.

(3) Microdontia involving single teeth

2. Macrodontia: Teeth larger than normal

(1) True Generalized Macrodontia

(2) Relative Generalized Macrodontia

(3) Macrodontia of single teeth

Size

Condition in which teeth are larger than normal Associated with Pituitary gigantism Exceedingly rare

(1) True Generalized Macrodontia

Normal or slightly larger than normal teeth in small jaws

Disparity in size gives the illusion of macrodontia It’s a heredity condition.

Results in crowding of teeth

Insufficient arch space

(2) Relative Generalized Macrodontia

•Teeth may appear normal in every aspect expect for its size.

•Usually seen with mandibular 3rd molars•Usually seen in the hemihypertrophy of the fcae ( The teeth of the involved side may be considerably larger than those of unaffected side)

• Uncommon condition• Unknown etiology

(3) Focal/Localized Macrodontia

SHAPE

• It’s a anomalies which arises from an attempt at division of single tooth germ by an invagination, result in incomplete formation of two teeth.

• Appearance of 2 crown with single root canal

• Seen both in decidious and permanent dentition.

• It has hereditary tendency

* Difficult to differentiate between germination and in case of fusion between normal tooth and supernumerary teeth.

1.Gemination

• Arises through union of two normally separated tooth germs

• It may be due to physical force or pressure produces contact of developing teeth and there subsequent tooth germ.

• Tooth may have separate or fused root canal.

• More common in deciduous than permanent dentition.

• May affect 2 normal teeth or btw normal and supernumerary teeth such as mesodens or distomolar.

• Shows hereditary tendency.

2. Fusion

• It’s a form of fusion occurs after root formation has been completed.

• Teeth united by cementum only.• Could be due to result of traumatic injury/

crowding of teeth with resorption of interdental bone so that two roots are in approximate contact and fused by depostion of cementum between them.

• It can occur before and after teeth have erupted.

3. Concrescence

• Noted more frequently in posterior and maxillary regions

• Often involves a 2nd molar Tooth in which its roots Closely approximate the adjacent impacted 3rd molar

Diagnosis:• By radiograph examination. • Since with fused teeth, extraction of one

may result in extraction of the other

Concrescence

• Angulation/ sharp bend / curve in root or crown of a formed tooth

• Trauma to a developing tooth can cause root to form an angle to normal axis of tooth

• Caused due to injury to the permanent teeth

4. Dilaceration

Dilaceration

Clinically:• Dilacerated teeth frequently

present difficult problem at the time of extraction.

• Preoparative radiograph is mandatory before any surgical procedure.

1. Anomalous structure resembling an eagle’s talon

2. Projects lingually from the cingulum area of maxillary and mandibular permanent incisor.

3. Poses problems for patient in term of esthetic, caries control, occlusal accomodation.

4. Seen in• Rubinstein Taybi syndrome.• It may be associated with other

somatic and odontogenic anomalies.

5. Talon’s Cusp

Also called Dens Invaginatus / Dilated composite odontome Developmental variation which

is thought to arise as a result of invagination in the surface of tooth crown before calcification has occurred.

Caused due to :• Increased localized external

pressure• Focal growth retardation• Focal growth stimulation

6. Dens in Dente

• Seen in permanent maxillary lateral incisors as an accentuation in the development of lingual pit.

• Condition can be bilateral

Histology:• Radicular invagination usually results from an

infolding of Hertwig’s sheath and takes its origin within the root after development is complete.

Dens in Dente

Clinically:

◦In mild form, deep invagination in lingual pit may not be evident clinically.

◦Food debris result in caries and infection of pulp and invagination extends nearly to apex of root.

Radiographically:

◦Radiographic picture shows severe disturbance in normal anatomic and morphologic structure of teeth.

◦Pear shaped invagination of enamel and dentin with narrow constriction at the opening on the surface of tooth approximating pulp.

• Also called as Leung’s PremolarOcclusal tuberculated premolarEvaginated odontome Occlusal enamal pearl

• Developmental condition that appears clinically as an accessory cusp or globule of enamal on the occlusal surface between buccal and lingual cusp of premolar

• Its unilateral or bilateral • Its rarely seen in molar, cuspid, incisor.

7. Dens Evaginatus

Pathogenesis:◦ It’s a proliferation and evagination of an area of inner enamal

epithelium and subjacent odontogenic mesenchyme into dental organ during early tooth development.

Clinical significance:Similar to talon cusp, extra cusp may contribute to incomplete eruption, displacement of teeth, pulp exposure with subsequent infection fallowing occlusal wear or fracture

It’s a dental anomaly in which the body of the tooth in enlarged at the expense of the root.

Bull- like teeth

Classified as –• Hypotaurodont – mild form• Mesotaurodont• Hypertaurodont – extreme

form

8. Taurodontism

Taurodontism

Possible Causes• Specialised or retrograde character• Premitive pattern• Mendelian recessive triat• Atavistic features• Mutation resulting from odontoblastic deficiency

during dentinogenesis of the roots

• Histology:• Caused by failure of hertwig’s

epithelial sheath to invaginate at the proper horizontal level

• Seen in • Taurodontism – occuring

concomitantly with amelogenesis imperfecta

• Klinefelter syndromeClinical features:• Effects either decidious / permanent

dentition.• Seen in molars, same quadrant.• Unilateral / bilateral or both

Taurodontism

Radiographic features:• Involved teeth is rectangular in shape

rather than taper towards roots.• Pulp chamber is large with greater

apico occlusal height than normal.• Roots are short• Bifercation / trifercation may be only

few millimeter above apices of the root.

Treatment:• No treatment is required

Taurodontism

9. Supernumerary roots:◦Developmental condition where teeth are single rooted, particularly in

mandibular bicuspids and cuspids.◦Maxillary and mandibular molars particularly third molars.Significance:◦ In Exodontia, roots broken off during extraction if unrecognized may

cause infection.

Anodontia Supernumerary

Development disturbances in Number of teeth.

1.Anodontia

• Lack of tooth development • Absence of teeth

Types 1. Complete Anodontia2. Partial Anodontia

• Hypodontia• Oligodontia

3. Pseudoanodontia4. False Anodontia

• When all teeth are missing

• Rare

• Often associated with a syndrome known as hereditary Ectodermal dysplasia

Complete Anodontia

lack of development of one or more teeth

Oligodontia lack of development of six or more

teethPseudoanodontiawhen teeth are absent clinically

because of impaction or delayed eruptionFalse Anodontiawhen teeth have been exfoliated /

extracted

Hypodontia

2.Supernumerary

• Results from continued Proliferation of permanent Or primary dental lamina to form third tooth germ

• It’s a hereditary tendency• Seen in all quadrants of jaw• Formed as a result of local, independent, conditioned

hyperactivity of dental lamina.• Etiology unknown• Occurs may be unilateral / bilateral, single / multiple

erupted / impacted.• Condition commonly associated with Cleft lip and

palate, cleidocranial dysplasia, gardner syndrome.• males > females

Supernumerary

Cleidocranial dysostosis

SupernumeraryClassification:Based on the morphology and location:1. Conical- peg shaped laterals2. Tubercular- teeth has more than one cusp/

tubercle3. Supplimental- duplication of teeth in normal

series eg: permanent maxillary lateral incisors4. Odontome- Any tumor of odontogenic origin

Thank you

References:

Neville, et al: Oral and Maxillofacial Pathology 3rd EditionShafer, et al: A textbook of Oral Pathology,

7th Edition