Developmental disturbances

• Developmental disturbances- In the size of the TOOTH

• Developmental disturbances –In the shape of the TOOTH

• Developmental disturbances –In the number of the TOOTH

• Developmental disturbances- In the structure of the TOOTH

Developmental disturbances in size of Developmental disturbances in size of teethteeth

1.1. MicrodontiaMicrodontia

2.2. MacrodontiaMacrodontia

Microdontia:-Microdontia:-This term is used to describe teeth which are This term is used to describe teeth which are smaller than normal.smaller than normal.• Three types of microdontia are recognisedThree types of microdontia are recognised

1).True generalised microdontia1).True generalised microdontia

2).Relative generalised microdontia2).Relative generalised microdontia

3).Microdontia involving a single tooth3).Microdontia involving a single tooth

• True generalised microdontia:- In this all the teeth are smaller than normalExample:Pituatory dwarfism.This condition is extremely rare

• Relative generalised microdontia:- Normal or slightly smaller than normal teeth are present. The jaws are some what larger than normal and so it is an illusion of true microdontia

• Microdontia involving only a single tooth:- It is rather common condition and often affects maxillary lateral incisor and third molar.

• One of the common forms is peg lateral,peg shaped OR cone shaped crown with shorter root is noticed

• Macrodontia:-Teeth are larger than normal. It may be classified as 1. True generalised macrodontia2. Relative generalised macrodontia3. Macrodontia of single tooth

True generalised macrodontia:- Here all the teeth are larger than normal, has been associated with pituitory gigantism

Relative generalised macrodontia:-It is common and is a result of the presence of normal or slightly larger than normal teeth in small jaws.

Macrodontia of single tooth:-It is relatively un common. Tooth may appear normal in every respect except for its size. This sige should not be confused with the fusion of the teeth. It is occasionally seen in cases of hemi hyper trophy of the face

Developmental disturbances in shape of Developmental disturbances in shape of teethteeth

• Gemination• Fusion• Concrescence• Dilaceration• Taloncusp• Dense in denty• Dense Evaginatus• Taurodontism• Super numerary roots

Gemination:- *Anomalie which arise from an attempt at division of a single

tooth germ by an invagination with resultant incomplete formation of two teeth.

*Structure is usually is one with two completely or incompletely separated crowns that have a single root and root canal.

*Seen in Deciduos and permanent dentitionFusion:-

*Anomalie arise through union of two normally separated tooth germs

*It has been thought that some physical force or pressure produces contact of the developing teeth and their subsequent fusion

*Fusion may also occur between a normal tooth and a supernumerary tooth

Clinical problems:-Appearance, spacing and periodontal conditions

FusionFusion

Concrescence:-* It is actually a form of fusion which occurs after root formation has

been completed* In this condition the teeth are united by cementum only* It could be a result of traumatic injury or crowding of teeth with

resorption of inter dental bone* Diagnosis is only by radiographs

Dialaceretion:-* It refers to an angulation or a sharp bend or curve in the root or crown

of a formed tooth.* It could be due to trauma during the period in which the tooth is

forming, with the result that the position of the calcified portion of the tooth is changed and the reminder of the tooth is formed at an angle

* This teeth frequently present a problem while extraction

Taloncusp:-* Anomalous structure resembling an eagle’s talon,projects

lingually from the cingulum areas of a maxillary or mandibular permanent incisor

* This cusp blends smoothly with the tooth except that there is a deep developmental groove where the cusp blends with the slopping lingual tooth surface

* composed of normal enamel dentin and a horn of pulp tissue* It should be considered in terms of esthetics caries control,

Occulusal accomadation* It appears to be more prevalent in person with Rubinsteni-

taybi syndrome

Densindente:-

* It is a result of invasination in the surface of the tooth crown before calcification has occurred

* Maxillary lateral incisors are most frequently involved and condition is frequently bilateral

Causes:-

1. Increased localised external pressure 2. Focal growth retardation3. Focal growth stimulation in certain areas of tooth bud

Radiograpically it is recognised as a pear shaped invasination of enamel and dentin with a narrow constriction at the opening on the surface of the tooth and closely approximating the pulp in its depth

• Dense evaginatus (occlusal enamel pearl);- Developmental condition that appears clinically as an accessory cusp or globule of the enamel on the occlusal surface between the buccal and lingual cusps of pre molars unilaterally OR bilaterally

* It could be proliferation and evagination of an area of the inner enamel epithelium and subjacent odontogenic mesenchyme in to the dental organ during early tooth development

Taurodontism:-* It is a peculiar anamoly in which the body of the tooth is enlarged at the

expensive of roots

Causes include:

* When the mandelian recessive trait * Atavastic feature* Mutation resulting from odontoblastic deficiency during

dentinogenesis of the roots

Super numerary roots:-

* An additional root develops to the involved tooth* Any tooth can exhibit these roots

Developmental disturbances in Developmental disturbances in number of Teethnumber of Teeth

1.1. AnodontiaAnodontia

2.2. Super numerary teethSuper numerary teeth

Anodontia:-Congenital absence of teethIt is of TWO types

1.Total anodontia

2.Partial Anodontia

Total anodontia:- All the teeth are missing,may involve both the deciduous and the

permanent dentition .Example :Ectodermal HypoplasiaPartial Anodontia:-* Any tooth may be congenitally missing* There is tendency for certain teeth to be missing more frequently than

others being the mandible second premolar commonestSuper Numerary teeth:-* The tooth may closely resemble the teeth of the group to which it

belongs I.e Molars or pre molars or Anteriors* Most common super numerary tooth are mesiodens followed by

maxillary fourth molar* Gardner’s syndrome consist of he multiple impacted super

numerary teeth

Developmental disturbances in Developmental disturbances in structure of Teethstructure of Teeth

1. Amelogenesis Imperfecta2. Enamel Hypoplacia3. Dentinogenesis imperecta

Amelogenesis Imperfecta:-* Represents a group of hereditary defects of enamel un associated with

any other generalised defects.* It is an ectodermal diturbance classified in to

1) Hypo plastic2) Hypo calcified3) Hypo maturation

• Clinically the crowns of the teeth may or may not show discolouration if present varies depending on the type of disorder, ranging from Yellow to dark brown

• In some cases enamel may be totally absent r it may have chalky texture or even a cheesy consistency or be relatively hard

• Sometimes the enamel is smooth or it may have numerous parallel vertical wrinkles or grooves

• It may be chipped or show depressions in the base of which dentin may be exposed

• Contact points between teeth are often open and occlusal surfaces and incisal edges frequently abraded

Enamel Hypoplasia:- * It is defined as a incomplete or defective formation of the organic

matrix of teeth* A number of different factors each capable of producing injury to the

amiloblast may give rise to this condition.

Causes are:-Nutitional deficiency (Vitamin A,D,C)-Examthematous diseases (Measels,chicken fox,scarlet fever)-Congenital syphilis-Hypocalcemia-Birth Injury,prematurity, RH Heamolytc disease-Local Infection or Trauma-Ingestion of chemical such as flouride

Radiographically:- * The most striking feature is the partial or total precocious* Obliteration of the pulp chamberand root cannals by

continued formation of the dentin.

Chemical and physical features:-• Chemical analysis shows that type-1 &2&3 increased

water content as much as above while the inorganic content is less than that of normal dentin

• Dentin dysplasia(rootless teeth):- It is a rare disturbance of dentin formation characterized

• By normal enamel but atypical dentin formation with abnormal pulpal morphology.

• Transmitted as an autosomal dominant character.

Type-1(Radicular dysplasia):-

These teeth characteristically exhibit extreme mobility&after only minor trauma as a result of their abnormally short roots.

Type-2(Coronal dysplasia) :-

-The permanent teeth how ever exhibit an abnormally -Large pulp chamber in the coronal portion of the tooth often

described as THISTLE TUBE in shape.

RegionalodontoplasiaRegionalodontoplasia

• They exhibit either delay or total failure in eruption.• Show a marked reduction in radiodensity , so that the teeth

assume a ghost appearance

Disturbances in the growth of the teeth:- 1. Premature eruption2. Eruption sequestrum3. Delayed eruption4. Impacted teeth 5. Ankylosed teeth

1).Premature eruption:-• Neonatal teeth are example for the premature eruption.• The premature eruption of the permanent teeth is

usually a sequelae of the loss of the deciduous teeth.• This could be the possibility of the endocrine

dysfunction.(hyperthyroidism) 2).Eruption sequestrum:- -It is tiny irregular spicule of the bone overlying the crown

of an erupting permanent molar found just prior to or immediately following the emergence of the tips of the cusps through the oral mucosa.

3).Delayed eruption:-• Local factors: -Fibromatosis gingivae• Systemic factors:-Rickets, cretinism,cleido cranial dysplasia

4).Impactedteeth:-• Individual teeth which are unerupted usually because of lack of

eruptive force.Causes:-• Lack of space • Rotation of the tooth buds resulting in teeth which are aimed in

the wrong direction • Because their long axis is not parallel to a normal eruptive path.

5).Ankylosedteeth:-• Most commonly mandibular second molars that have undergone a

variable degree of root resorption & then have become ankylosed to the bone.

Causes:- -Trauma,infection,disturbed local metabolism or a genetic influence

• Hypoplasia results only if the injury occurs during the time the teeth developing or more specifically during the formative stage of enamel development.Once the enamel is calcified no such defects can be produced

E.H due to exanthmatous fever:-• Pitting varilog and this pits tend to strain.The clinical

apearances of it mau be very unsightly.

• E.H due to congenitalsyphilis:--Involves the maxillary and mandibular permanent incisors and

the first molars

-The anterior teeth affected are called HUTCHINSONS TEETH and molars are referred to as mulberry molars , moon’s molars, fournier,s molars.

The anterior teeth will be screw driver shaped ,themesial and distal surfaces of the crown tapering and converging towards the cervical margin and it could be due the absence of cental tubercle or calcification center.

-In the first molar crowns ,the enamel of the occlusal surfaces and the occlusal third of the tooth appears to be arranged in an agglomerate mass of the globules rather than in well formed cusps.

The crown is narrower on the occlusal surfaces than at the cervical margin.

E.H due to local infection or traumaE.H due to local infection or trauma

• It is occasionally seen,only a single tooth is involved ,most commonly one of the permanent maxillary incissor or maxillary or mandibular premolar.

• There may be any degree of hypoplasia ranging from the mild brownish discoluration of the enamel to sever pitting or irregularity of the tooth crown.

• This single tooth is called turners toothand the conditionis called as Turners hypoplasia.

E.H due to flourideE.H due to flouride

• The iungestion of the flouride containing drinking water during the time of tooth formation may result in Mottled enamel.

• The permissible amount flouride ,for the clinicalsignificance is at a level below 0.9to1 ppm of flouride.

• Above this level it causes the disturbances. • Questionable changes appear in the enamel like white flecking or

spotting of the enamel.• Mild changes manifested by white opaque areas involving more of

the tooth surface area.• Moderate or severe changes showing pitting &brownish staining of

the surface and even a corode appearance of the teeth.

Mild fluorosisMild fluorosis

Moderate fluorosisModerate fluorosis

Severe FluorosisSevere Fluorosis

Dentinogenesis imperfectaDentinogenesis imperfecta

• Type-1,type-2,type-3. are present.• In type-1deciduous dentition is more affected than the

permanent teeth.• In type-2 both the dentitions are equally affected.• In the type-3both the dentitions are affected.• The colour of the teeth ranges from a gray to brownish

violet or yellowish brown.

• The enamel may be lost early through fracturing away especially on the incisal or occlusal surfaces of the teeth presumbaly because of an abnorma dentinoenamel junction.

• The scalloping of the D.E.Jnot formed.• Radiographically :-the most striking feature is the partial or

total precocious obliteration of the pulpchambers and root cannals by continued formation of dentin

Type IType I Dentinogenesis Imperfecta Dentinogenesis Imperfecta

Type IIType II Dentinogenesis Imperfecta Dentinogenesis Imperfecta

Dentindysplasia(Root less teeth)Dentindysplasia(Root less teeth)

• It is a rare disturbance of dentin formation characterised by normal enamel but atypical dentin formation with abnormal pulpal morphology

• Transmitted as an autosomal dominant character.• types:type1(radicular),type2(anamolous dysplasia)• Type-1:-These teeth characteristically exhibit extra

mobility &are commonly exfoliated prematurely or after only minor trauma as a result of their abnormally short roots.

• Type-2:-(coronal)the permanent teeth how ever exhibit an abnormally large pulp chamber in the coronal portion of the tooth often described as Thistle-tube in shape.

Regional odontoplasiaRegional odontoplasia

• They exhibit either delay or a total failure in eruption.• Radiographic features:-show a marked reduction in

radio density so that the teeth assume a Ghost appearance.

Disturbances in the growth of the teethDisturbances in the growth of the teeth

1. Premature eruption

2. Eruption sequestrum

3. Delayed eruption

4. Impacted teeth

5. Ankylosed teeth

• Premature eruption:-• Neonatal teeth are example for the premature eruption.• The premature eruption of the permanent teeth is usually a sequelae

of the loss of the deciduous teeth.• This could be the possibility of the endocrine dysfunction.

(hyperthyroidism) • Eruption sequestrum:-• It is tiny irregular spicule of the bone overlying the crownof an

erupting permanent molar found just prior to or immediately following the emergence of the tips of the cusps through the oral mucosa

Delayed eruption:-Local factors: - Fibromatosis gingivaeSystemic factors:- Rickets, cretinism,cleido cranial dysplasia

Impacted teeth:-• Individual teeth which are unerupted usually because of

lack of eruptive force.Causes:--Lack of space -Rotation of the tooth buds resulting in teeth which are aimed in the

wrong direction -Because their long axis is not parallel to a normal eruptive path.

Ankylosedteeth:-

Most commonly mandibular second molars that have undergone a variable degree of root resorption & then have become ankylosed to the bone.

Causes:-

Trauma,infection,disturbed local metabolism or a genetic influence

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