Attrition

Definition:

Loss of tooth structure due to tooth-to-tooth contact without involvement of any foreign substance.

Causes:

• Normal mastication
• Bruxism (teeth grinding)
• Clenching habits

Clinical Features:

• Flattened occlusal or incisal surfaces
• Matching wear facets on opposing teeth
• Shiny, polished surfaces
• Reduced crown height in severe cases

Example:

A patient with night-time bruxism showing flat worn incisors and molars.

Abrasion

Definition:

Loss of tooth structure due to mechanical wear by external objects or substances.

Causes:

• Aggressive tooth brushing
• Hard-bristled toothbrush
• Abrasive toothpaste
• Holding objects between teeth (pins, nails, pipe smoking)

Clinical Features:

• V-shaped or wedge-shaped cervical defects
• Usually on the buccal surfaces near the CEJ
• Smooth and shiny surface

Example:

A person who brushes horizontally with excessive force develops cervical notches.

Erosion

Definition:

Loss of tooth structure by chemical dissolution without bacterial involvement.

Causes:

Extrinsic acids

• Soft drinks
• Citrus fruits
• Sports drinks
• Occupational acid exposure

Intrinsic acids

• GERD
• Recurrent vomiting
• Eating disorders

Clinical Features:

• Smooth, silky-glazed enamel
• Cupping of occlusal surfaces
• Broad shallow depressions
• Restorations may appear raised above surrounding tooth surface

Example:

A patient with gastric reflux showing palatal erosion of maxillary anterior teeth.

Abfraction

Definition:

Loss of tooth structure at the cervical region caused by occlusal stress and flexure of the tooth.

Theory:

Heavy occlusal forces cause the tooth to bend slightly. Stress concentrates at the cervical area, leading to microfractures and loss of enamel and dentin.

Clinical Features:

• Deep wedge-shaped cervical lesions
• Sharp internal and external angles
• Usually on premolars
• Often associated with bruxism

Example:

A patient with heavy occlusal loading develops a narrow deep cervical defect on a premolar.

Quick Comparison Table

FEATURE	ATTRITION	ABRASION	EROSION	ABFRACTION
CAUSE	Tooth-to-tooth contact	External mechanical wear	Chemical dissolution	Occlusal stress/flexure
LOCATION	Occlusal/incisal	Cervical region	Any exposed surface	Cervical region
SURFACE	Flat wear facets	Smooth notch	Smooth cupped surface	Deep wedgeshaped defect
ASSOCIATED WITH	Bruxism	Tooth brushing	Acids/GERD	Bruxism, occlusal stress

Attrition → Against another tooth

Abrasion → Abrasive object

Erosion → Acid eats tooth

Abfraction → Bending (flexure) of tooth 

How to identify clinically

• Flat occlusal wear facet? → Attrition
• Toothbrush notch near CEJ? → Abrasion
• Acid-related smooth cupping? → Erosion
• Deep sharp cervical wedge in a bruxer? → Abfraction

GERD (Gastroesophageal Reflux Disease) is one of the most important intrinsic causes of dental erosion.

What is GERD?

GERD is a condition in which stomach contents, including hydrochloric acid (HCI), repeatedly flow back into the esophagus and sometimes into the mouth. 

How does it cause dental erosion?

• Stomach acid has a very low pH (around 1-2).
• Enamel begins to dissolve when the pH falls below about 5.5.
• Repeated exposure of teeth to gastric acid causes chemical loss of enamel and dentin.
• This process occurs without bacterial involvement, so it is classified as erosion, not caries.

Characteristic Dental Findings

• Erosion of the palatal (lingual) surfaces of maxillary anterior teeth is classic.
• Smooth, shiny enamel surface.
• Cupping of occlusal surfaces.
• Yellow appearance as dentin becomes exposed.
• Increased dentin hypersensitivity.
• Restorations may appear raised above the surrounding tooth surface because the tooth structure wears away.

Why are the palatal surfaces affected first?

During reflux, gastric acid tends to contact the palatal surfaces of the upper front teeth first, making them particularly vulnerable.

Dental History Clues

Patients may report: 

• Heartburn
• Acid regurgitation
• Sour or bitter taste in the mouth
• Chronic cough
• Hoarseness of voice
• Frequent throat clearing

Management

1. Identify and refer for medical evaluation if GERD is suspected.
2. Advise rinsing with water after a reflux episode.
3. Avoid brushing immediately after acid exposure (wait about 30 minutes).
4. Use fluoride toothpaste and topical fluoride.
5. Dietary counseling.
6. Restore severely eroded teeth when necessary.

Carbonated Drinks and Dental Erosion

Carbonated drinks (soft drinks, cola, energy drinks, sports drinks, flavored sodas) are a major extrinsic cause of dental erosion. 

Why do they cause erosion?

These drinks contain acids such as: 

• Phosphoric acid (common in cola drinks) 
• Citric acid (common in fruit-flavored drinks) 
• Carbonic acid (from carbonation)

These acids lower the pH of the mouth below the critical pH of enamel (~5.5), causing gradual dissolution of enamel.

Clinical Features

• Smooth, shiny enamel surface
• Loss of enamel luster
• Broad shallow depressions
• Cupping of occlusal surfaces
• Increased sensitivity
• Yellow appearance due to dentin exposure

Risk Factors

• Frequent sipping throughout the day
• Holding the drink in the mouth before swallowing
• Drinking before bedtime
• Energy drinks and sports drinks (often highly acidic)

Prevention

• Reduce frequency of acidic drinks.
• Drink quickly rather than sipping for long periods.
• Use a straw when possible.
• Rinse with water afterward.
• Do not brush immediately after drinking acidic beverages (wait about 30 minutes).
• Use fluoride toothpaste.

Abfraction is believed to be caused by excessive occlusal forces that make the tooth flex (bend slightly) during function.

When a person bites, clenches, or grinds heavily:

1. Strong forces are applied to the tooth.
2. The tooth undergoes microscopic flexure.
3. Stress concentrates at the cervical region (near the CEJ).
4. Enamel and dentin develop microfractures.
5. Over time, a wedge-shaped cervical defect forms.

Common Causes

• Bruxism (teeth grinding)
• Clenching habit
• Heavy occlusal contacts
• Malocclusion or occlusal interferences
• Excessive chewing forces

Clinical Features

• Deep wedge-shaped lesion at the cervical area
• Sharp internal angles
• Often affects premolars
• May be associated with tooth sensitivity