Dentinogenesis Imperfecta Overview

Dentinogenesis Imperfecta

• Hereditary developmental disturbance of dentin
• Absence of systemic disorder
• Affected teeth are gray to yellowish-brown in color

Hypoplastic Type

• Defective formation of dentin matrix
• Complete absence of enamel or enamel present in focal areas
• Enamel thickness is usually below normal
• Quality of enamel is normal but quantity is affected
• Lack of differentiation of ameloblast cells
• Little or no matrix formation

Hypocalcification Type

• Alteration in enamel rod and rod sheath structures
• Cheesy consistency of teeth

Dentinogenesis Imperfecta Classification

• Dentinogenesis Imperfecta I: Occurs with Osteogenesis Imperfecta. Opalescent teeth. Tooth appears ready for a prosthetic crown.
• Dentinogenesis Imperfecta II: Both dentitions are affected.
• Dentinogenesis Imperfecta III: Similar to type II. Multiple pulp exposures, periapical radiolucencies, and variable appearance. Both dentitions are affected.

Clinical and Radiographic Features

• Widening of the pre-dentin layer:
  • Severe dysplasia of remaining dentin
  • Large areas of inter-globular dentin
  • Short, disoriented, irregular, and widely spaced dentinal tubules
  • Scanty odontoblasts lining the pulp
  • Smooth DEJ
• Irregular tubular pattern of dentin
• Reduced enamel epithelium around unerupted teeth showing many irregular calcified bodies
• Abnormal matrix structure and mineral deposition
• Multiple pulpal exposures in deciduous dentition

Micrognathia

• Also known as Mandibular Hypoplasia
• Condition of a very small lower jaw in children
• Two types:
  • Congenital: Present at birth
  • Acquired: Develops after birth

Dentinal Features

• Normal Enamel and Mantle Dentin
• Irregular tubules in dentin
• Large areas of uncalcified matrix
• Enamel doesn’t form to full thickness on newly erupted developing teeth.
• Teeth exhibit complete absence of enamel or there may be presence of enamel on some focal areas
• Enamel thickness is usually below normal
• Quantity is affected, but quality of formed enamel is normal

Dentinogenesis Imperfecta Histological Features

• Enamel and mantle dentin are normal
• Dentin composed of irregular tubules with large areas of uncalcified matrix

Developmental Anomalies

• Malformation: A defect caused by a localized error in morphogenesis leading to abnormal shape or structure, interfering with function. Example: Cleft palate

• Deformation: An alteration in the shape or structure of a previously normally formed part. Example: Torticollis

• Anomaly: Any deviation from normal. Similar to malformation but without interference in function. Example: Peg-shaped lateral incisors

• Anomalad: Malformation resulting in subsequent structural changes. Example: Robin anomalad, where hypoplasia of the mandible leads to cleft palate and respiratory difficulties.

Congenital Developmental Anomalies

• Present at birth or before birth during intrauterine life
• Result from either heredity or environmental influences
• Examples: Cleft lip and palate, Downs syndrome

Hereditary Developmental Anomalies

• Genetically transmitted from parents to offspring.
• Definite genetic location identified: Example: Downs Syndrome (Trisomy 21)
• Definite genetic location NOT identified: Example: Diabetes

Acquired Developmental Anomalies

• Defects develop during intrauterine life due to pathological environmental conditions.
• Can be prenatal, neonatal, or postnatal.
• Example: Congenital Syphilis
  • Notched incisors
  • Mulberry molars

Developmental Disturbances of Oral and Para-Oral Structures

• Lip Pits: Congenital lip pits.
  • Paramedian lip pits: Common (1-20%), can be as deep as 2 cm. Can be autosomal dominant in some cases.
  • Commissural: Bilateral blind tracts at the angle of the lip, up to 4 mm.

Histopathology

• Median rhomboid glossitis: Smooth or nodular surface covered by atrophic stratified squamous epithelium, overlying a moderately fibrosed stroma. Debris accumulation and candidal pseudohyphae are not uncommon.
• Lingual thyroid nodule: Consist of normal mature thyroid tissue. May exhibit colloid degeneration.
• Fungiform and filiform papillae: Not seen, although surface nodules may mimic or represent anlage of these structures.
• Inflammation: Mild to moderately intense chronic inflammatory cell infiltrate may be seen within subepithelial and deeper fibrovascular tissues.

Amelogenesis Imperfecta

• Also known as Hereditary Enamel Dysplasia/Hereditary Brown Enamel/Hereditary Brown Opalescent Tooth.
• A group of conditions caused by defects in the genes encoding enamel matrix proteins.
• Affects both dentition (deciduous and permanent).
• Types:
  • Hypoplastic type: Defective matrix deposition.
  • Hypocalcification type: Defective calcification.
  • Hypomaturation type: Defective maturation.
  • Hypomaturation-hypoplastic with taurodontism: Abnormal matrix structure and mineral deposition.

### Dentinogenesis Imperfecta

• Type II: Appearance of cheesy consistency. Both dentition affected.
• Type III: Similar to type II but with clinical and radiological variations, including multiple pulp exposures, periapical radiolucencies, and variable radiographic appearance. Both dentition affected.
• Multiple pulpal exposures in deciduous dentition

Micrognathia

• Also known as Mandibular hypoplasia.
• Condition where a child has a very small lower jaw.
• Etiology of congenital: Unknown, but associated with Congenital Heart Disease or Pierre Robin Syndrome.
• Acquired postnatal: Due to ankylosis of the joint, as a result of trauma or infection.

Causes of Micrognathia

• Congenital:

  • Pierre Robin syndrome
  • Catel Manzke syndrome
  • Cerebrocostomandibular syndrome

• Intrauterine acquired conditions: Congenital syphilis.

Facial Hemiatrophy

• Also known as Parry Romberg Syndrome, Progressive Facial Hemiatrophy, Progressive Hemifacial Atrophy.
• Description: Unilateral atrophy of the face.
• Oral manifestations:
  • Dental anomalies: Incomplete root formation, delayed eruption, severe facial asymmetry.
  • Eruption of teeth on the affected side may be retarded.

Facial Hemihypertrophy

• Also called Friedreich’s Disease.
• Significant unilateral enlargement of the face.
• Represents hyperplasia of tissues rather than hypertrophy.
• Associated Syndromes:
  • Neurofibromatosis
  • Beckwith Wiedemann syndrome

This quiz explores the hereditary condition of Dentinogenesis Imperfecta, detailing its types and their characteristics. Learn about the differences between hypoplastic and hypocalcification types, as well as the classification of Dentinogenesis Imperfecta. Perfect for dental students and professionals!