Developmental anomalies of oral cavity : hard tissue Structures

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develpmental anomalies

Developmental anomalies of oral cavity : hard tissue Structures


  • Malformations or defects resulting from disturbance of growth and development are known as developmental anomalies
  • Congenital anomalies : The defects, which are present at birth or before birth during the intrauterine life
  • Hereditary developmental anomalies : When certain defects are inherited by the offspring from either of the parents
  • Acquired anomalies : They develop during intrauterine life due to some pathological environmental conditions. They are not transmitted through genes.
  • Hamartomatous anomalies : A hamartoma can be defined as an excessive, focal overgrowth of mature, normal cells and tissues, which are native to that particular anatomic location.
  • Idiopathic anomalies : Developmental abnormalities of unknown cause are called idiopathic anomalies.
  • Syndrome : It is a term used to describe a group of related symptoms that commonly occur together and may have a specific underlying cause.
  • Developmental Anomalies

Causes of developmental disorders incudes:

  • Genetic factors
  • Prenatal factors
  • Environmental factors
  • Neurological factors

Developmental disturbance in size of teeth


  • It refers to teeth which are smaller than normal size.
  • There are 3 types of Microdontia
    •   1. True- generalized Microdontia :
    •    All the teeth are smaller than normal
    •   2. Relative-generalized Microdontia :
    •       The teeth may be of normal size/smaller but due to large jaw, they give illusion of small tooth.
    •   3. Microdontia involving single teeth :  Localized microdontia seen.
  • Prevalence / Incidence rate:
  • 1.5 to 2 %
  • Clinical significance :
    • In microdontia, teeth are often spaced which may be disturbing cosmetically.
    • There may be difficulty in speech and taking food.
  • Management:
    • Crown and Bridge placement for aesthetic rehabilitation.


  • It refers to teeth which are larger than normal. 
  • There are 3 types of Macrodontia:
    •    1. True Generalized Macrodontia :
    • All teeth are larger than normal and are associated with pituitary dwarfism
    •    2. Relative Generalized Macrodontia : Seen in cases of micrognathia jaw, teeth may be Larger or normal in size.
    •   3. Macrodontia of single tooth Localized macrodontia may be seen 
  • Clinical Features: Malocclusion may occur
  • Impactions may occur
  • Management: Orthodontic treatment. Extraction of impacted teeth.
  • Prevalence / Incidence rate:
    •     0.03 to 1.9 %

Developmental disturbance in shape of teeth

1. Gemination

  • Geminated teeth are anomalies which arise from an attempt at division of single tooth germ by an invagination, with resultant incomplete formation of two teeth.
    • Seen in both primary and permanent dentitions.
    • Has higher frequency in the anterior and maxillary regions.
    • Incisors and canines are most commonly affected.
    • Teeth demonstrate a pronounced labial or lingual groove
    • Gemination can result in crowding and delayed or ectopic eruption of the underlying permanent teeth and hence have to be extracted in certain cases.
    • The labial or lingual groove are prone to develop caries and hence in such cases fissure sealant should be used

2. Fusion

  • Fused teeth arise through union of two normally separated tooth germ.
    • Fusion may be complete or incomplete.
    • The tooth may have separate or fused root canals.
    • Teeth demonstrate a pronounced labial or lingual groove
    • Affects both primary and permanent teeth.
    • Most frequently occurs in the mandible.
    • Fusion Results in spacing
    • The labial and lingual grooves are prone to develop caries
  • Prevalence / Incidence rate:
    • 0.1 to 1.5%

3. Concrescence

  • Teeth are united by the cementum only.
  • It arises as a result of traumatic injury or crowding of teeth with resorption of the interdental bone so that the two teeth are in approximate contact and become fused by deposition of cementum.
    • Most commonly seen in the posterior and maxillary regions.
    • It can occur before or after the teeth have erupted.
    • No therapy is usually required unless the union interferes with eruption, then surgical removal may be warranted.

4. Dilaceration

  • Dilaceration refers to an angulation or a sharp bent in the root or crown of a tooth.
  • It arises after an injury that displaces the calcified portion of the tooth germ and the reminder of the tooth is formed at an abnormal angle.
    • Most commonly affected teeth are the mandibular third molars followed by the maxillary second premolars and mandibular second molars.
    • Failure of eruption is often seen .
    • Altered deciduous teeth often demonstrate inappropriate resorption and results in delayed eruption of permanent teeth.
    • Extraction is indicated in such conditions.
    • Teeth with abnormal eruption may be exposed and orthodontically moved into proper position.

5. Talon cusp

  • Talon Cusp is an anomalous structure resembling an eagles talon
    • Talon cusp projects lingually from the cingulum areas of maxillary or mandibular permanent incisor.
    • A deep developmental groove is present in lingual tooth surface.
    • Composed of normal enamel, dentin and contains a horn of pulp tissue.
    • Most commonly seen in association with Rubinstein-Taybi syndrome.
    • Talon cusp on maxillary teeth interfere with occlusion and should be removed
    • The developmental groove may be prone to caries.
    • Removal with out loss of vitality may be accomplish through periodic grinding of the cusp resulting in tertiary dentine deposition and pulpal recession

6. Dens Invaginatus

  • Dens Invaginatus is a deep surface invagination of the crown or root that is lined by enamel. •
    • Coronal
    • Radicular
    • Most commonly affected teeth are permanent lateral incisors.
    • Depth of invagination varies from a slight enlargement of the cingulum pit to a deep infoldings that extends to the apex.
    • Invagination may be large and resemble a tooth with in a tooth and hence the term ‘Dens In Dente
  • Three types of coronal invagination is seen:
    • Type I – Invagination is confined to the crown
    • Type II – Invagination extents below the cementoenamel junction and ends In a blind sac that may or may not communicate with the adjacent pulp.
    • Type III – Invagination extents through the root and perforates in the apical or lateral radicular area without communication with the pulp.
  •  Radicular Dens invaginatus arises secondary to proliferation of hertwig’s root sheath with the formation of strip of enamel that extends along the surface of the root.
    • In type I Invaginations the opening of the invagination should be restored after eruption to prevent caries.
    • In larger invagination the content of the lumen and any carious dentin must be removed and calcium hydroxide base must be placed to treat micro communications with the pulp.
    • In type III endodontic therapy is required

7. Dens Evaginatus

  • Dens Evaginatus appears clinically as an accessory cusp or globule of enamel on the occlusal surface between buccal and lingual cusp of pre molars.
  • Occurs as a result of proliferation and evagination of an area of inner enamel epithelium and odontogenic mesenchyme into the enamel organ during tooth development.
    • May interfere with occlusion and should be removed
    • Removal with out loss of vitality may be accomplish through periodic grinding of the cusp
  • Prevalence / Incidence rate: 1 to 4%

8. Taurodontism

  • It is the enlargement of the body and pulp chamber of a multirootedd teeth with apical displacement of the pulpal floor.
    • Affected teeth tend to be rectangular.
    • Increase in apico-occlusal height
    • Bifurcation lies close to the apex
    • No cervical constriction
  • The degree of taurodontism has been classified into:
    • Mild (hypotaurodontism)
    • Moderate(mesotaurodontism)
    • Severe(hypertaurodontism)
  • No specific therapy is required

9. Enamel Pearls

  • They are ectopic collections of enamel.
  • These are hemispherical structures consisting of enamel or may contain dentin and pulp.
    • Most frequently found on the roots of maxillary molar.
    • They appear as well defined, radiopaque nodules along the root surface.
    • Mature internal enamel pearls appear as areas of radio density extending from the dentino-enamel junction into the coronal dentin
    • Enamel pearls are areas of weak periodontal attachment.
    • Hence meticulous oral hygiene should be maintain

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