Tooth Anomalies and Pathology

Oral Anatomy and Histology: Tooth Anomalies and Pathology

Role of Dental Assistant

  • Recognition of anomaly
  • Patient education
  • Treatment considerations

Types of Developmental Disorders

  • Inherited Disorders:
    • Caused by an abnormal gene.
  • Developmental Disorders:
    • Abnormalities during the development process.
    • Congenital Disorder: Present at birth, can be inherited or developmental; often with unknown causes.
  • Genetic Factors:
    • Malformations from chromosomal abnormalities.
  • Environmental Factors:
    • Called teratogens, may include infections, drugs, or radiation exposure (Bird & Robinson, 2021).

Disturbances in Jaw Development

  • Macrognathia: Abnormally large jaw structure.
  • Micrognathia: Abnormally small jaw structure.
  • Exostoses:
    • A benign bony growth projecting from the surface of a bone.
  • Torus Palatinus:
    • A bony overgrowth at the midline of the hard palate.
  • Torus Mandibularis:
    • A bony overgrowth on the lingual surface of the mandible (Bird & Robinson, 2021).

Disturbances in Lip, Palate, and Tongue Development

  • Cleft Lip:
    • Occurs when maxillary and medial nasal processes fail to fuse.
  • Cleft Palate:
    • Results when palatal shelves fail to join with the primary palate.
  • Cleft Uvula:
    • Mildest form of cleft palate, involving the uvula.
  • Ankyloglossia:
    • Commonly referred to as tongue-tie, it results from a short lingual frenum extending to the tongue's apex (Bird & Robinson, 2021).

Tooth Anomalies

  • Clinical Descriptions:
    • Abnormal teeth due to disruptions during development affecting tooth size, number, and shape.
  • Factors Influencing Anomalies:
    • Stage of development, length of effects, hereditary or environmental causes.
    • More frequent in permanent dentition.

Etiology of Anomalies

Stages of Development:

  1. Initiation
  2. Proliferation
  3. Histo-differentiation
  4. Morpho-differentiation
  5. Apposition
  6. Maturation

Abnormal Number of Teeth

  • Initiation Stage:
    • Lack of initiation within the dental lamina can result in an absence of either a single tooth or an entire dentition.
  • Associated Conditions:
    • Ectodermal dysplasia.
    • Endocrine dysfunction.
    • Systemic disease.
    • Radiation exposure (Fehrenbach & Popowics, 2020).

Anodontia (Hypodontia)

  • Definition:
    • Partial or complete absence of teeth.
  • Commonly Affected Teeth:
    • Permanent third molars.
    • Maxillary lateral incisors.
    • Mandibular second premolars (Fehrenbach & Popowics, 2020).

Hyperdontia

  • Definition:
    • Presence of supernumerary teeth.
  • Common Locations:
    • Between permanent maxillary incisors.
    • Distal to third molars.
  • Etiology:
    • Hereditary factors (Fehrenbach & Popowics, 2020).

Mesiodens

  • Definition:
    • A small extra central incisor that erupts between the two centrals (Fehrenbach & Popowics, 2020).

Abnormal Size

  • Bud Stage of Development (Proliferation):
    • Abnormal proliferation can cause a tooth or multiple teeth to be larger or smaller than usual.
    • Generally related to genetic factors; endocrine dysfunction is associated with cases of extreme size changes (Fehrenbach & Popowics, 2020).
  • Macrodontia:
    • Abnormal increase in tooth size, often due to childhood hyperpituitarism (gigantism) (Fehrenbach & Popowics, 2020).
  • Microdontia:
    • Complete Microdontia: All teeth are smaller than average, rare and often linked to hypopituitarism or Down’s syndrome.
    • True Partial Microdontia:
    • Commonly affects permanent maxillary lateral incisors and permanent third molars.
    • Involves hereditary factors (Fehrenbach & Popowics, 2020).

Abnormal Shape

  • Late Stages of Development (Cap-Maturation):
  • Changes can arise from the processes of proliferation and morphodifferentiation, leading to unusual crown or root shapes (Fehrenbach & Popowics, 2020).

Dens in Dente

  • Occurrence during Cap Stage:
    • Enamel organ invaginates into the dental papilla and is typically seen in permanent lateral incisors.
    • Etiology: Hereditary factors (Fehrenbach & Popowics, 2020).

Gemination

  • Definition:
    • The tooth germ attempts to divide, producing a large single-rooted tooth with one pulp cavity and a crown that exhibits “twinning” for anterior teeth.
  • Notable Characteristics:
    • The correct number of teeth remains intact.
    • An unsuccessful attempt is marked by an incisal notch (Bird & Robinson, 2021).

Fusion

  • Definition:
    • Union of two adjacent tooth germs, resulting in a single large tooth with two pulp cavities.
  • Characteristics:
    • One less tooth in the dentition, more common in anterior teeth of the primary dentition.
  • Etiology:
    • Pressure (Fehrenbach & Popowics, 2020).

Tubercle

  • Characteristics:
    • Small rounded enamel extension mainly located on posterior occlusal surfaces or anterior lingual surfaces.
  • Etiology:
    • Caused by trauma, pressure, or metabolic disease impacting the enamel organ (Fehrenbach and Popowics, 2020).

Enamel Pearl

  • Occurs during Apposition and Maturation stages:
  • Definition:
    • Sphere of enamel on the root surface.
  • Etiology:
    • Displacement of ameloblasts to the root surface (Fehrenbach & Popowics, 2020).

Hypercementosis

  • Definition:
    • Excess deposition of cementum on root surfaces.
  • Potential Causes:
    • Local and systemic factors such as trauma, inflammation, supraeruption, pituitary gigantism, arthritis, calcinosis, Paget’s disease, rheumatic fever, and goiter.
    • Commonly occurs in adults, with frequency increasing with age (Haring, 2015).

Concrescence

  • Occurs during Apposition and Maturation stages:
  • Definition:
    • Union of the root structures of two or more teeth through cementum.
  • Commonly Affected Teeth:
    • Permanent maxillary molars.
  • Etiology:
    • Traumatic injury or crowding (Fehrenbach & Popowics, 2020).

Root Formation Disturbances

  • Dilaceration:
    • Causes distorted roots due to severe crown angulation from injuries or pressure during development.
  • Flexion:
    • A bend or deviation restricted to the root.
  • Accessory Roots:
    • May arise from trauma, pressure, or metabolic disease affecting Hertwig’s epithelial root sheath (HERS) during root formation (Fehrenbach & Popowics, 2020).

Structural Anomalies

  • Resulting from disturbances in enamel and dentin formation during Apposition and Maturation stages (Fehrenbach & Popowics, 2020).

Enamel Dysplasia

  • Defined as a reduction in the quantity of the enamel matrix (Fehrenbach & Popowics, 2020).
  • Clinical Presentation:
    • Teeth exhibit pits and intrinsic color changes in enamel (Bird and Robinson, 2021).

Amelogenesis Imperfecta

  • A specific type of enamel hypoplasia/dysplasia with hereditary etiology.
  • Affects all teeth in both primary and permanent dentitions.
  • Characteristics:
    • Teeth may have very thin enamel that chips off or none at all, leading to yellow crowns.
    • Severity varies (Fehrenbach & Popowics, 2020).
  • Hereditary Enamel Hypoplasia:
    • Characterized by hard and glossy crowns with a yellow or cone-shaped pattern (Bird & Robinson, 2021).

Dental Fluorosis

  • Definition:
    • A change in the appearance of the tooth's enamel.
  • Presentation:
    • Ranges from mild white spots to staining and pitting.
  • Occurrence:
    • Primarily affects young children exposed to excessive fluoride during tooth development.

Turner’s Teeth

  • Definition:
    • Hypoplasia of enamel in a single permanent tooth.
  • Common Etiologies:
    • An infection present during the retention of a primary tooth, primarily affects canines or premolars; trauma to primary teeth, mostly happens in anterior areas (Geetha Priya, John & Elango, 2010).

Congenital Syphilis

  • Hutchinson’s Incisors:
    • Abnormally shaped permanent front teeth often linked with congenital syphilis (Treponema pallidum) (Bird & Robinson, 2021).
  • Mulberry Molars:
    • A first molar with an occlusal surface that displays pitting due to congenital syphilis, with nodules replacing the cusps.

Dentin Dysplasia

  • Definition:
    • Faulty development of dentin.

Dentinogenesis Imperfecta

  • Hereditary condition characterized by:
    • Blue-gray or brown teeth with an opalescent sheen.
  • Clinical Implications:
    • Normal appearance of enamel, but due to abnormal dentin, enamel chips off, leading to severe attrition (Fehrenbach & Popowics, 2020).

Tetracycline Staining

  • Mechanism:
    • Results from incorporation into dentinal tissue during calcification when tetracycline is administered, binding chemically to dentin for the tooth's lifespan.
  • Presentation:
    • Visible discoloration ranging from yellow or gray to brown varying by dosage and body weight (Sánchez, Rogers & Sheridan, 2004).

Odontoma

  • Etiology:
    • Unknown; may involve local trauma, inflammation, infectious processes, dental lamina remnants, hereditary anomalies, odontoblastic hyperactivity, or genetic disruptions controlling dental development (Satish, Pradhadevi and Sharma, 2011).
  • Complex Odontomas:
    • Irregular mass of calcified dental tissues without the morphology resembling rudimentary teeth (Satish, Pradhadevi and Sharma, 2011).
  • Compound Odontomas:
    • Composed of odontogenic tissues arranged orderly to form multiple tooth-like structures without resembling normal teeth (Satish, Pradhadevi and Sharma, 2011).
  • Ameloblastoma:
    • A tumor comprised of dental lamina remnants (Bird & Robinson, 2021).

Degenerative Changes

  • Attrition:
    • Involves wearing down of incisal or occlusal surfaces due to frictional contact, grinding, or occlusal interactions (Fehrenbach & Popowics, 2020).
  • Abrasion:
    • Mechanical wear of tooth surfaces, particularly on buccal/lingual surfaces, often from toothbrush abrasion and recession.
  • Bruxism:
    • An oral habit characterized by involuntary gnashing, grinding, and clenching of teeth, typically occurring during sleep, often associated with stress (Bird & Robinson, 2021).
  • Abfraction:
    • V-shaped notches in dentin mistaken for abrasion; caused by shear and tensile stresses affecting the cervical enamel junction (CEJ) during slight bending (Fehrenbach & Popowics, 2020).
  • Erosion:
    • Chemical wear of the enamel leading to its dissolution (Fehrenbach & Popowics, 2020).

Implications of Abnormal Eruption of Teeth

  • Premature Eruption:
    • Natal teeth present at birth; neonatal teeth erupt within the first 30 days.
  • Ankylosis:
    • Fusion of bone to cementum and dentin in primary teeth, preventing exfoliation.
  • Impaction:
    • Occurs when a tooth remains unerupted beyond its normal eruption time (Bird & Robinson, 2021).

Review Questions

  1. The absence of all teeth is called Anodontia.
  2. Hyperdontia may also be known as Supernumerary teeth.
  3. The following image shows an example of which anomaly? Gemination – indicated by the notched incisal edge.
  4. The absence of one or more teeth is known as Hypodontia.
  5. The following image is showing an example of Microdontia.
  6. The following image is an example of Attrition.
  7. What is the condition that can cause teeth to appear like this? Congenital syphilis.
  8. The hereditary condition that involves thin enamel or enamel absence is Amelogenesis Imperfecta.
  9. Abrasion refers to mechanical wear while recession describes the wear of gingival tissue exposing more of the tooth structure.
  10. Characteristics of Dental Fluorosis include changes ranging from mild white spots to severe staining and pitting occurring due to excessive fluoride intake during tooth development.