Developmental Alterations of Teeth

These alterations may be primary or arise secondary to environmental influences (e.g., concrescence, hypercementosis, and dilaceration).

Developmental Alterations of Teeth

Number ➔   • Hypodontia ➔   • Hyperdontia ➔   Anodontia

Size ●      Microdontia ●     Macrodontia

Shape ➢    Gemination ➢    • Fusion ➢    • Concrescence ➢    • Accessory cusps ➢    • Dens invaginatus ➢    • Ectopic enamel ➢    • Taurodontism ➢    • Hypercementosis ➢    • Accessory roots ➢    • Dilaceration

Structure ★    Amelogenesis imperfecta (AI) ★    • Dentinogenesis imperfecta (DGI) ★    • Dentin dysplasia type I (DD-I) ★    • Dentin dysplasia type II (DD-II) ★    • Regional odontodysplasia

 

Number

Hypodontia

Hypodontia

Hypodontia: less than six missing teeth (not taking into account the third molars)

Oligodontia: six or more missing permanent teeth (not taking into account the third molars)

–

Anodontia: no teeth present

 

Hypodontia in a Thai boy.

Typical intra-oral and radiographic presentations in a boy with ectodermal dysplasia with multiple missing teeth; the teeth that are present are small and conical in shape. In the regions where teeth are absent, alveolar bone does not develop.

A, X-linked hypohidrotic ectodermal dysplasia caused by an EDA mutation. Note the severe hypodontia, sparse hair, and hyperpigmented skin around his eyes. B, His mother, who is heterozygous for the EDA mutation is phenotypically normal.

Conical primary teeth are often associated with missing permanent teeth. This child had an autosomal recessive form of ectodermal dysplasia and was missing almost all of the permanent teeth. (C) These teeth have been built up with composite resin strip crowns. (D) Radiographic appearance of the same child at 15 years of age. Most of the primary teeth have exfoliated even in the absence of a permanent successor. There has also been loss of bone in the region of the tuberosity due to pneumatization of the sinus that will complicate implant placement.

 

Frequency

Primary teeth	~0.1–0.7%	male : female	ratio unknown
Permanent teeth	~2–9%	male : female	1 : 1.4

Third molars > maxillary lateral incisors > second premolars > mandibular central incisors.

 

 Oligodontia/ anodontia is a major clinical feature :Major conditions manifesting

Ectodermal dysplasias.

Dento-alveolar clefting. Trisomy 21 (Down syndrome). Chondroectodermal dysplasia (Ellis–van Creveld syndrome). Rieger syndrome. Incontinentia pigmenti. Oro-facial-digital syndrome Craniosynostosis syndromes.

Hyperdontia

Syndromes associated with hyperdontia

These syndromes are all rare, but probably the best known is cleidocranial dysplasia

  

 

Radix Entomolaris and Paramolaris

Supernumery roots

 

Gemination & Fusion

 

Gemination of a mandibular lateral incisor. The crown has a groove on the labial surface and is wider than normal.

 

Gemination: Teeth that are structurally united and have developed from the same tooth germ.

 

 

Concrescence

   

Two teeth during development or after they are completely formed, Joined with cementum

Common teeth are Posterior teeth

 

Taurodontism

Taurodontism is an apical extension of the pulp chamber that increases its apico-occlusal height and displaces the radicular bifurcation closer to the apex of a molar tooth.

Enamel pearls

Dilaceration

Dilaceration is an extraordinary curving or angulation of tooth roots.

Two developmental anomalies: Fusion and dilaceration

 

Dens Invaginatus & Evaginatus

 

Dens Invaginatus (Dens-in-dente)

 

Invagination of a layer of enamel and dentin into pulp.

 

  

                   

Oehlers’ classification of dens invaginatus       

(a) and (b) clinical view showing the healing of the fistula 15 days after Calcium hydroxide dressing (c) a full thickness mucoperiosteal flap rising, exposing the apical lesion and a narrow root denudation (d) periapical pathologic tissues curettage and root end resection removing of the non sealed part of the canal (e) perfect apical sealing of biodentine orthograde obturation (f) post apical resection periapical radiograph

Lateral Incisor 12: Lingual Groove

Case of developmental lingual groove causing primary endodontic infection. A, Preoperative radiograph of tooth 12. A gutta-percha marker extends to the apex. The radiograph is suggestive of a deep lingual groove or two separate roots. No caries or other abnormalities were present. B, A large lingual and periradicular defect developed after gutta-percha obturation of both canals (see photo in D). C, One-year recall after surgery showed radiographic healing, no symptoms, and a 3-mm probing depth. D, A 12-mm probing depth is demonstrated before surgical exploration. E, A large area of bone loss on the palatal and a deep lingual groove are evident during surgery

 

 

Dens Evaginatus

Developmental out folding of an enamel organ Usually on the occlusal surface of a premolar or a molar

talon cusp /dens evaginatus

 

Clinical significance

1. If the cusp is small and asymptomatic, no treatment is required.
2. If the cusp has deep developmental grooves which are non-carious, they should be cleaned and all the plaque and debris should be removed. After this they should be sealed with a fissure sealant or composite.
3. If the grooves are decayed, the carious portion should be removed and the cavity has to be filled with glass ionomer cement or composite resin.
4. If there is any occlusal interference, the cusp has to be reduced. The cusp may or may not contain vital pulp tissue. If a substantial portion of the cusp is to be reduced, it should be done conservatively followed by desensitizing agent application.

 

Structure

	Amelogenesis imperfecta	Dentinogenesis imperfecta	Dentin
Genetic	Hypoplastic Hypomaturation Hypocalcified Chronological hypoplasia Molar-incisor hypomineralisation	Shell teeth	Dentinal dysplasia  Regional odontodysplasia Multisystem disorders with associated dental defects Hypophosphatasia
Infective	Congenital syphilis
Metabolic	Rickets Hypoparathyroidism
Other acquired developmental anomalies	Fetal alcohol syndrome
Drugs	Tetracycline pigmentation  Cytotoxic chemotherapy Fluorosis

 

Hereditary Conditions of Teeth

	Amelogenesis Imperfecta	Dentinogenesis Imperfecta	Dentin Dysplasia
Heredity	Many patterns	Autosomal dominant	Autosomal dominant
Teeth affected	All teeth, both dentitions	All teeth, both dentitions	All teeth, both dentitions
Tooth color	Yellow	Yellow	Normal
Tooth shape	Smaller, pitted	Extreme occlusal wear	Normal
X-ray findings	Normal pulps/dentin; reduced enamel	Obliterated pulps, short roots, bell crowns	Obliterated pulps, periapical cysts/granulomas
Systemic manifestations	No	Osteogenesis imperfecta occasionally	No
Treatment	Full crowns	Full crowns	None; early tooth loss