Dental Attrition Overview

Study Notes

Attrition is the mechanical wear of tooth structure due to tooth-to-tooth contact without external substances.
Age-dependent process, physiological attrition is a natural part of aging and is influenced by various factors.
Parafunctional habits, like clenching or grinding, can also contribute to attrition.
Opposing porcelain restorations can lead to attrition as porcelain is harder than enamel.
Lack of posterior support can cause increased stress on anterior teeth, resulting in attrition.
Intracapsular TMJ disorders can influence chewing patterns and lead to excessive attrition.

Tooth Surface Loss:
- Occlusal Surface Attrition:
  - Flattening, faceting, or reverse cusping
  - Peripheral, ragged, sharp enamel edges
  - Well-defined wear facets with enamel worn off and dentin exposure
  - Loss of mamelons
- Proximal Surface Attrition:
  - Mesiodistal dimension of the teeth is decreased
  - Widening of the proximal contact areas
  - Mesial drifting
  - Overall reduction in dental arch

Pathological wearing off of dental hard tissues due to mechanical processes involving foreign or exogenous objects.
Repeated introduction of foreign objects into the mouth causes the condition.
Patient Related Factors:
- Brushing technique
- Brushing frequency
- Force applied
Material Related Factors:
- Bristle type and stiffness
- Abrasiveness of toothpaste
- pH of toothpaste

Tooth Surface Loss:
- Depending on the etiology, the patterns may vary from localized to diffuse.
- Tooth Brushing Abrasion:
  - Rounded grooves or V-shaped defects in the cervical region
  - Right-handed patients on the left and vice versa
  - Localized: Canine and premolar
  - Generalized: Wrong brushing technique

Wedge-shaped defect at or near the cemento-enamel junction of a tooth.
Also termed "cervical stress lesions".
Theory suggests tooth flexure and bending in the cervical area due to occlusal compressive forces and tensile stresses, leading to microfractures of enamel and dentin.
Facilitated by the thin structure of enamel and the low packing density of the Hunter-Schreger band at the cervical area.

Tooth Surface Loss:
- Similar to toothbrushing abrasion lesions but more angular.
- Well-defined internal and external angles.
- Wedge or V-shaped lesions.
- Contributing factors like erosion or abrasion can modify the clinical appearance, making the angles less sharp and the outline broader and more saucer-shaped.

Chemical loss of dental hard tissues by non-bacteriogenic acid, resulting from a drop in pH of the oral cavity below a critical level of 5-5.5.
Intrinsic Erosion:
- Caused by gastric content, including hydrochloric acid and pepsin, entering the oral cavity.
- Gastric acid has a pH of approximately 2, highly erosive to dentition.
- Contributing factors include:
  - Pregnancy
  - GERD
  - Hiatus hernia
  - Alcoholism
  - Anorexia nervosa
  - Bulimia nervosa
- Extrinsic Erosion:
  - Caused by external agents, like acidic foods and drinks.
  - The location and severity of tissue loss vary depending on the etiology and areas related to the passage of the corrosive element.

Tooth Surface Loss:
- Intrinsic Erosion:
  - Translucent, darker, glazed appearance.
  - Rounded and smooth lesions.
  - Dished-out broad, shallow concavities.
  - Cupping or cratering.
  - Enamel chipping or fracture.
  - Shorter teeth.
Extrinsic Erosion:
- The clinical presentation varies widely depending on the specific cause and location of the erosive agent.
- Examples include:
  - Dentist-related:
    - Remnants of pulp tissue left after root canal treatment.
    - Incomplete removal of root canal sealers.
    - Use of intracanal medicaments like phenolic or iodoform-based materials.
  - Intrinsic stains:
    - Systemic causes (mild form):
      - Tetracycline staining or Fluorosis.
      - Developmental defects like enamel hypoplasia/hypocalcification.
      - Amelogenesis/Dentinogenesis imperfecta.
    - Cannot be removed by prophylactic procedures.
      - Yellowish aging stains are fastest to respond.
      - Brown fluorescent stains are moderately responsive.
      - Blue-grey stains are the slowest to respond.

External stains internalized into the tooth due to:
- Presence of cracks.
- Caries: Orange to brown discoloration.
- Leaky restorations.
- Reduced salivary flow enhances staining deposition.

Defective enamel development, can be the result of:
- Inherited condition called amelogenesis imperfecta.
- Congenital enamel hypoplasia.
- Improper enamel matrix formation due to injury of ameloblasts during enamel formation.

Enamel has an insufficient amount of calcium due to injury of ameloblasts during mineralization of the formed matrix.
Enamel covers the tooth surface but can be thin and weak, giving teeth an opaque or chalky appearance.