DENT 306: Oral Physiology Unit III Quiz

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Questions and Answers

What type of stimuli can cause the onset of toothache?

Only sweet foods

Only cold air

Only hot fluids

Hot fluids or concentrated chemicals or cold air (correct)

What determines the diagnostic significance of tooth sensitivity?

The thickness of enamel

The color of the tooth

The presence of enamel

The reaction to hot and cold stimuli (correct)

Which of the following statements is true regarding electrical stimulation of teeth?

Electrical stimulation can evoke pain from sound teeth (correct)

Electrical stimulation is used to diagnose tooth decay

Only diseased teeth can experience pain from electrical stimulation

Electrical stimulation does not indicate the vitality of the pulp

Where does the sensation of toothache originate?

In the dentin or pulp Signup and view all the answers

What is the consequence of removing the pulp of a tooth?

Loss of tooth sensitivity Signup and view all the answers

What happens to pulpal nerves as intrapulpal pressure increases?

Neural activity in pulpal nerves increases Signup and view all the answers

Which nerve branches contribute to the sensation of toothache?

The autonomic and trigeminal nerves Signup and view all the answers

Which dental structures are insensate to stimulation?

Enamel and cementum Signup and view all the answers

What primarily contributes to the sensitivity of dentin?

Presence of nerve endings in the dentinal tubules Signup and view all the answers

Which of the following stimuli has been shown to initiate toothache?

Draft of cold air Signup and view all the answers

What is the relationship between osmotic pressure and pain sensation in exposed dentin?

Higher osmotic pressure correlates with increased pain reports Signup and view all the answers

What is the effect of thermal stimulation on dentin?

It can produce pain with both cold and heat Signup and view all the answers

How might the clinical presentation of dental pain be explained?

Changes in intrapulpal pressure affecting neural activity Signup and view all the answers

What type of stimuli leads to pain when touch is applied to dentin?

Air pressure and touch Signup and view all the answers

Which theory of pain transmission suggests a direct relationship between nerve activation and pain perception?

Direct Neural Theory Signup and view all the answers

What is a common first symptom indicating carious exposure of dentin?

Pain from sweet substance application Signup and view all the answers

What happens when 1 mm of dentin is exposed?

Around 300,000 odontoblast cells are damaged. Signup and view all the answers

Which process involves the differentiation of cells to form dentin?

Formation of reparative dentin. Signup and view all the answers

What role does the odontoblastic process play in dentinogenesis?

It helps in the deposition of collagenous matrix. Signup and view all the answers

Which characteristic describes reparative dentin compared to normal dentin?

It has fewer and more twisted tubules. Signup and view all the answers

How does the tubule system contribute to caries progression in dentin?

It facilitates rapid spread of caries. Signup and view all the answers

What can stimulate the formation of reparative dentin?

Cavity lining materials. Signup and view all the answers

Which of the following is NOT a clinical consideration regarding dentin exposure?

Exposed dentin provides protection against bacteria. Signup and view all the answers

In which phase of dentinogenesis is the deposition of hydroxyapatite crystals crucial?

Mineralization. Signup and view all the answers

Which theory suggests that nerve endings in the dentin respond directly to stimuli?

Direct Neural Theory Signup and view all the answers

What is the primary structure presumed to be excited by stimuli in the Transduction Theory?

Odontoblast process Signup and view all the answers

What is the main mechanism by which the Hydrodynamic Theory explains the sensation of pain?

Fluid movement in dentinal tubules Signup and view all the answers

Which type of dentin formation occurs as a response to physiological and pathological stimuli?

Sclerotic Dentin Signup and view all the answers

What phenomenon describes the filling of empty tubules with air due to the death of odontoblasts?

Dead Tracts Signup and view all the answers

Sclerotic dentin is characterized by which of the following features?

Increased mineralization of tubules Signup and view all the answers

Reparative or tertiary dentin is formed in response to what type of environmental changes?

Physiological and pathological stimuli Signup and view all the answers

Which structure is primarily responsible for sensing mechanical disturbances in dentinal tubules?

Plexus of Raschkow Signup and view all the answers

Why is the Transduction Theory less favored among researchers?

No neurotransmitter vesicles in odontoblast processes Signup and view all the answers

What kind of changes occur in dentin as a result of age and physiological stimuli?

Formation of dead tracts, sclerotic, and reparative dentin Signup and view all the answers

Study Notes

Toothache

Toothache is one of the most intense forms of pain, prompting patients to seek dental care.
The tooth's nociceptive capacity signals potential damage, triggered by stimuli like hot fluids, concentrated chemicals, or cold air.

Tooth Sensitivity

Tooth sensitivity has clinical diagnostic importance; cold (ethyl chloride) or hot stimuli are used to assess vitality.
Modern “pulp testers” enable electrical stimulation to diagnose pulp viability, even in healthy teeth.

Neuroanatomical Considerations

Toothache sensations originate in dentin or pulp receptors, as evidenced by sensitivity loss upon pulp removal.
Enamel and cementum lack nerve endings and are insensitive, while pulp and dentin are richly innervated.

Nerve Physiology

Autonomic and trigeminal nerve branches enter the tooth and expand towards the pulp cavity, facilitating pain responses.
Increased intrapulpal pressure from heat or sympathetic stimulation heightens pulpal neural activity, possibly causing throbbing pain.

Behavioral Studies of Dentin Sensitivity

Chemical stimuli to exposed dentin can trigger pain, often indicating caries or defective restorations; osmotic pressure affects pain reporting.
Cold air drafts or heat can initiate toothaches, and pressure from touch, air streams, or drying also induces pain.

Dentin Innervation

Dentin contains nerve endings in tubules; these are closely associated with odontoblastic processes, contributing to sensitivity.

Theories of Pain Transmission

Direct Neural Theory: Stimuli directly activate nerve endings in dentin, leading to pain responses.
Transduction Theory: Suggests odontoblast processes transmit stimulus to nearby nerve endings, though lacking supporting evidence.
Hydrodynamic Theory: Most accepted; it posits that stimuli disturb fluid movement in dentinal tubules, activating pain mechanisms.

Odontoblasts respond to stimuli by forming defensive structures like dead tracts, sclerotic dentin, and reparative dentin.

Dead Tracts

Formed when odontoblasts disintegrate or die, leading to air-filled tubules, which are visible as white or black under specific lighting.

Sclerotic Dentin

Results from mineralization of dead tracts, making dentin tubules more opaque and transparent due to collagen and apatite deposition.

Reparative Dentin

Formation occurs in response to injury, sealing off damaged areas to facilitate pulp healing; it features fewer, twisted tubules compared to normal dentin.

Dentinogenesis Phases

Matrix Formation: Approximately 4 microns of pre-dentin created daily at cusp tips with collagen deposition.
Mineralization: Hydroxyapatite crystals mineralize the collagen matrix, gradually calcifying.

Clinical Considerations

Exposing 1 mm of dentin damages around 300,000 odontoblast cells.
Rapid caries spread is facilitated by the dentin tubule system, and procedural trauma can harm the pulp, while cavity liners can stimulate reparative dentin formation.

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Description

Test your understanding of the physiology of receptors associated with the oral cavity, focusing on pain from dental structures such as toothaches. This quiz is designed for students of DENT 306, covering essential concepts that impact oral health and dental practice.