Developmental and Acquired Anomalies of the Dentition

Composition of enamel

~96 mineral, 3% water, <1% organic matrix; by weight

Composition of Dentin

70% mineral, 20% organic matrix, 10% water; by weight

What fiber makes up most of the organic matrix of dentin?

Collagen makes up 95% of the organic matrix of dentin

Causes of dental anomalies

Genetic factors (hereditary), metabolic disturbances, developmental disturbances

Congenital (Developmental) dental anomalies

Present at birth or during tooth development; underlying cause is genetic or a disturbance during odontogenesis

Environmental (Acquired/Idiopathic) dental anomalies

Occur after tooth formation due to external factors like trauma, infection, or medication

What is microdontia?

A type of morphological anomaly characterized by abnormally small teeth.

What are the two types of microdontia presentations?

Localized (e.g., peg lateral) or generalized.

Which teeth are often affected by microdontia?

Maxillary lateral incisors and third molars.

What are common treatments for microdontia?

Veneers, crowns, or bonding for aesthetics.

What is macrodontia?

A morphological anomaly characterized by abnormally large teeth.

What are the two types of presentations of macrodontia?

Localized or generalized.

What condition is often associated with macrodontia?

Pituitary gigantism.

What are the treatment options for macrodontia?

Reshaping or extraction.

What is the definition of fusion in dentistry?

Anomaly of shape characterized by the union of two adjacent tooth germs, resulting in a single large tooth.

How can fusion be identified?

By counting the teeth in the arch, which shows one tooth is missing; the combined tooth has a large crown and often two distinct pulp chambers.

Gemination: Type of anomaly, definition, identification

Anomaly of shape characterized by the attempt of a single tooth germ to divide, resulting in a bifid crown

Identified by counting the teeth in the arch shows a normal number, the tooth has a single root and pulp chamber, but two crowns

What is Dens Invaginatus?

A type of dental anomaly characterized by an infolding of enamel and dentin into the pulp chamber.

How does Dens Invaginatus appear on a radiograph?

It appears as a 'tooth-within-a-tooth'.

What is a major risk associated with Dens Invaginatus?

It is highly susceptible to caries and pulp necrosis.

What is Dens Evaginatus?

An abnormality of shape characterized by an out-pouching of enamel and dentin.

What is the clinical appearance of Dens Evaginatus?

It appears as an extra cusp or tubercle, often on premolars.

What is Taurodontism?

Anomaly of shape characterized by the enlargement or elongation of the pulp chamber.

How does Taurodontism appear on a radiograph?

It appears as a rectangular pulp chamber with a low furcation area and short roots.

Which type of teeth are affected by Taurodontism?

It only affects permanent teeth.

What is another name for Taurodontism?

'Bull teeth'

What type of anomaly are Hutchinson's Teeth?

External anomaly of shape

What is the cause of Hutchinson's Teeth?

Congenital syphilis

What are characteristic features of Hutchinson's Teeth?

Notched incisors, occlusal surface appearance gave rise to the Mulberry molar

Carabelli's traits: External abnormality of shape

Accessory cusps or tubercles on teeth; ex. 5th cusp on ML cusp of 1st maxillary molar

Enamel Pearls: Type of anomaly, common teeth to present on, how to diagnose, issues

External anomaly of shape most commonly found in the furcation of maxillary molars; found on radiographs

Can result in periodontal issues, and a problem to clean around clinically

Talon Cusps: Type of anomaly, common teeth to present on, description, issues

External anomaly of shape often seen as a small enamel projection in the cingulum area of anterior teeth; projection may have a pulp horn

Possible occlusal interferences

Dilacerations (Flexion): Type of anomaly, description, cause

Tooth root anomaly, a severe tooth root bend (45-90 degrees) caused by trauma/crowding during development/eruption

Dens in Dente (tooth within a tooth)/Invagination Root anomaly: Description, how to diagnose

Invagination of the enamel organ within the crown of the tooth, deep pit/groove in cervical area; found radiographically

Segmented Roots

Separation of root due to trauma during root formation

Dwarfed (Short) Roots

Normal crowns with very short roots, often hereditary, can be an unwanted result of orthodontic treatment (too rapid treatment

Which teeth are single rooted and most affected by accessory roots/root canals?

Mandibular canines and premolars

Which multirooted teeth are most affected by accessory roots/root canals?

Third molars

What is Concrascence?

An anomaly of tooth root resulting from the joining of two teeth at roots through cementum.

What tissue is involved in Concrascence?

Only cementum is involved.

How does Concrascence differ from fusion?

In Concrascence, only cementum is involved, unlike fusion.

When does Concrascence occur?

Concrascence occurs after eruption.

What is hypercementosis?

Excess cementum around a tooth after eruption.

What is a characteristic feature of hypercementosis?

Non-neoplastic deposition of excessive cementum along the roots of one or more teeth.

What are some potential causes of hypercementosis?

Idiopathic or associated with local/systemic factors such as inflammation, trauma, developmental disorders, vitamin A deficiency, and Paget disease of bone.

Which mutations are associated with hypercementosis?

Mutations in ENPP1 and GACI

What is hypodontia?

The congenital absence of 1-5 teeth.

What is oligodontia?

The congenital absence of 6+ teeth.

What is anodontia?

The complete congenital absence of teeth.

What causes hypodontia, oligodontia, and anodontia?

Disturbances in the dental lamina during tooth bud formation.

Which genes are often linked to hypodontia and oligodontia?

MSX1 and PAX9.

Commonly affected teeth by hypodontia

Third molars, maxillary, lateral incisors, mandibular second premolars

Clinical appearance of hypodontia

Gaps in the dentition, peg-shaped maxillary laterals are often associated

Radiographic appearance of hypodontia

Absence of the tooth germ in the jaw

Treatments for hypodontia

Orthodontics, implants, or bridges

What is hyperdontia?

The presence of 1+ extra teeth.

What are mesiodens?

The most common supernumerary teeth, located between the maxillary central incisors.

What shapes can supernumerary teeth be?

They can be conical or have a normal shape.

What is the most common region for extra teeth in the mandibular arch?

The mandibular premolar region.

What percentage of the population is affected by hyperdontia?

.3-3.8% of the population.

In which arch do 90% of supernumerary teeth occur?

The maxilla.

What is a common treatment for hyperdontia?

Extraction of the supernumerary tooth/teeth.

Why might extraction be necessary in cases of hyperdontia?

Because the supernumerary tooth/teeth can block the eruption of permanent teeth.

What is Amelogenesis Imperfecta?

An anomaly of structure defined as a group of inherited conditions affecting enamel formation.

How common is Amelogenesis Imperfecta in the US?

It affects 1 in 14,000 individuals.

How many genes are associated with Amelogenesis Imperfecta?

There are 17+ associated genes, including ENAM, AMELX, AMBN, KLK4, and MMP20.

What are the clinical features of the Hypoplastic Type of Amelogenesis Imperfecta?

Features include pitted, grooved, or thin enamel.

What are the clinical features of the Hypomaturation Type of Amelogenesis Imperfecta?

Features include normal thickness but mottled, opaque, and soft enamel.

What are the clinical features of the Hypocalcified Type of Amelogenesis Imperfecta?

Features include normal shape but soft, cheesy enamel that chips easily.

How does Amelogenesis Imperfecta appear radiographically?

It appears less opaque than normal dentin.

What is Dentinogenesis Imperfecta?

Dentinogenesis Imperfecta is an anomaly of structure defined as an inherited condition affecting dentin formation.

How common is Dentinogenesis Imperfecta in the US?

It is found in 1 in 6,000 individuals in the US.

What are the three subtypes of Dentinogenesis Imperfecta?

Type 1: Syndromic, Type 2: Non-syndromic, Type 3: Non-syndromic.

What is the genetic cause of Type 1 Dentinogenesis Imperfecta?

Type 1 is associated with Osteogenesis Imperfecta and mutations in COL1A1 or COL1A2.

What causes Types 2 & 3 Dentinogenesis Imperfecta?

Types 2 & 3 are caused by mutations in the DSPP gene.

What are the clinical features of Dentinogenesis Imperfecta?

Clinical features include characteristic blue/brown opalescent teeth and enamel that often flakes off, leaving exposed/sensitive dentin.

What are the radiographic features of Dentinogenesis Imperfecta?

Obliterated pulp chamber and root canals (Type 1 or 2)

Enlarged pulp (Type 3)

Short roots with bulbous crowns

How might Dentinogenesis Imperfecta be managed?

Full-coverage crowns, root canals (if possible), or extractions

Neonatal Teeth: Type of anomaly and definition

Chronological anomaly characterized by the presence of teeth on babies earlier than 4 months; rare condition

Natal vs. Neonatal Teeth

Natal: Present at birth

Neonatal: Develop in in the individual's first month of life

What is early eruption in dentistry?

A chronological anomaly characterized by the abnormal eruption of teeth before the expected dental age.

What is delayed eruption in dentistry?

A chronological anomaly characterized by the abnormal eruption of teeth after the expected dental age.

What can cause early or delayed eruption of teeth?

They can be associated with syndromes or systemic conditions and may be caused by bisphosphonates if taken during tooth eruption.

Transposition: Type of anomaly and definition

Positional anomaly characterized by misplaced tooth buds which develop in the wrong location; may have teeth which 'exchange' positions

Causes of Envrionmental/Acquired Anomalies

External factors, NOT genetics

-Trauma: Physical injury to a primary tooth can affect the developing permanent successor

-Infection: Periapical infection of a primary tooth can affect the permanent tooth bud

-Medication: Certain drugs, like tetracycline, can stain teeth during development

Turner's Tooth

A permanent tooth with a localized area of hypoplasia or discoloration caused by trauma or infection to the primary tooth

Tetracycline Staining

Discoloration caused by ingestion of tetracycline antibiotics during tooth development; teeth have horizontal gray/brown/yellow bands that fluoresce under UV light

Dental Fluorosis

Discoloration caused by excessive fluoride intake during tooth development; appears as white flecks or mottled enamel, severe cases may present with brown staining and pitting

Why is diagnosis of dental anomalies crucial?

Can be a sign of systemic disease or genetic syndromes, treatment planning often involves interdisciplinary care and aesthetic concerns can affect patient self-esteem

Which rare disease can result in enamel defects?

Loeys Diets Syndrome

Which rare disease is caused by mutations in the ALPK1 gene?

ROSAH syndrome

Which anomaly of number is autosomal dominant with incomplete penetrance, X-linked?

Hypodontia/anodontia

Which anomaly of number is autosomal dominant?

Hyperdontia

Which anomaly of size is autosomal dominant?

Microdontia (Peg laterals)

Which anomaly of shape is autosomal dominant, X-linked?

Taurodontism

Which anomaly of structure can be autosomal dominant or recessive, and X-linked?

Amelogenesis imperfecta

Dentinogenesis imperfecta and dentin dysplasia share a similar mode of inheritance, what is it?

Autosomal dominant