DH 170 LO6: Dentinal Hypersensitivity

What is the primary characteristic of Dentinal Hypersensitivity (DH)?

DH is characterized by short, sharp pain from exposed dentin that occurs in response to thermal, mechanical, or chemical stimuli, and cannot be ascribed to any other form of dental defect or pathology.

What are the three types of stimuli that can elicit pain in dentinal hypersensitivity?

Thermal stimuli, mechanical stimuli, and chemical stimuli.

What is the structure of dentin comprised of?

Numerous thin tubules that transverse from the pulp to the outer dentinal surface.

How far do sensory nerve fibers extend into the dentinal tubules?

10 to 15% of the distance of the tubules (from the pulpal side to the DEJ).

What specific sensory nerve fiber is thought to be responsible for dental hypersensitivity, and what sensation does it evoke?

A-delta fibers, which are small myelinated fibers that evoke a sensation of well-localized sharp pain.

What type of nerve fiber is susceptible to the same types of stimuli as A-delta fibers but responds more sensitively to electrical stimulation?

A-beta fibers.

What type of pain is associated with the stimulation of unmyelinated C-fibers?

Dull, poorly localized, aching type of pain that is usually associated with pulpal pain.

What are the three characteristics of hypersensitive dentin?

1. Dentinal tubules open to the oral cavity; 2. Large and numerous tubules; 3. Thin, poorly calcified, or breached smear layer.

Define the "smear layer."

A deposit of salivary proteins, debris from dentifrices, and/or other calcified matter that blocks the dentinal tubules.

Explain the Hydrodynamic Theory of pain transmission.

It proposes that stimuli (thermal, mechanical, chemical) are transmitted to the pulp surface via the movement of fluid found within the dentinal tubules.

According to the Hydrodynamic Theory, what anatomical condition must exist for dentinal hypersensitivity to occur?

An open dentinal tubule channel must traverse from the exposed dentin surface to the vital pulp.

What are the two most common results leading to the exposed dentin necessary for dentinal hypersensitivity?

Gingival Recession OR Enamel Loss.

Define Gingival Recession.

The apical migration of the free gingival margin (FGM) resulting in exposure of the tooth root.

Why is exposed cementum particularly susceptible to wear?

The exposed cementum is thin and easily eroded away.

What are the four recognized causes of Gingival Recession?

1. Age; 2. Tooth type; 3. Bacterial plaque biofilm; 4. Trauma from traumatic toothbrushing.

What is the most common factor associated with recession?

Bacterial plaque biofilm, which results in biofilm-induced gingivitis.

Where is GENERALIZED RECESSION most commonly found?

The buccal cervical regions of teeth.

Where is LOCALIZED RECESSION most commonly found?

Mandibular anterior teeth.

What four factors related to traumatic toothbrushing can contribute to recession?

Technique (e.g., "scrubbing"), frequency, duration, and toothbrush filaments.

Is there evidence of a difference between manual and powered toothbrushes causing recession?

No evidence of a difference between manual and powered toothbrushes.

What are the four causes of Enamel Loss?

1. Attrition; 2. Abrasion; 3. Erosion; 4. Abfraction.

Define Attrition.

Tooth-to-tooth wear due to masticatory forces, such as clenching, grinding (bruxism), or malocclusion.

How does Abrasion typically appear, and what is it commonly a result of?

It appears as rounded ditching/notches near the gingival margin, commonly seen as a result of traumatic toothbrushing.

How much quicker does cementum abrade compared to enamel?

Cementum abrades 35 times quicker than enamel.

What is the single most common cause of enamel loss?

Erosion.

What are the chemical causes of Erosion?

Acid reflux disease (GERD), excessive vomiting (from morning sickness or anorexia/bulimia), or a highly acidic oral environment (frequent consumption of acidic or carbonated drinks; frequent sugar consumption).

Define Abfraction.

The loss of tooth structure due to biomechanical forces (the ongoing flexion, tension, and compression forces) exerted in the cervical area of a tooth from mastication.

How does Abfraction typically appear?

As a V-shaped defect at the CEJ.

Besides gingival recession and enamel loss, what are two additional causes of Dentinal Hypersensitivity?

Periodontal therapy (instrumentation & polishing, or some types of periodontal surgery) and Teeth whitening.

What percentage of the adult population reports dentinal hypersensitivity?

About 25–30%.

What age range is the reported peak prevalence for DH?

Between 30 and 40.

DH is most prevalent in which regions of the mouth?

On the buccal cervical regions of teeth.

What is the clinical description for diagnosing dentinal hypersensitivity?

"A Diagnosis of Exclusion".

List two essential CLINICAL criteria for diagnosing DH.

Sensitivity or pain when stimulus is applied, AND exposed dentin at the site of sensitivity.

List three criteria that must be absent during a CLINICAL diagnosis of DH.

No clinical signs of dental caries; no evidence of fracture lines in tooth structure; and restoration margins flush with tooth structure.

List three essential RADIOGRAPHIC criteria for diagnosing DH.

No apical radiolucency; no radiolucent areas under restorations; and absence of distinct fracture lines.

What are the three steps in the management of DH after ruling out alternative causes?

1. Identify the cause and risk factor(s); 2. Educate the client and discuss behavior modification (OHI, dietary choices, product recommendation); 3. Begin with the most non-invasive treatment options.

What are the two primary mechanisms of action for desensitizing agents?

1. Desensitizes / Inactivates Nerve; 2. Occludes Dentinal Tubules.

What two environmental conditions must be controlled for desensitizing effects to be successful?

Control of an acidic oral environment AND effective daily oral biofilm control.

Self-Applied (OTC) Desensitizing Products are recommended for what level of sensitivity?

Mild-moderate sensitivity.

Why is regular and continuous use of self-applied agents necessary?

To avoid the recurrence of symptoms.

What is the most common OTC desensitizing agent, and what is its mechanism?

5% Potassium Nitrate, which inactivates nerve fibers.

What two agents used in desensitizing toothpaste have high-quality evidence supporting their efficacy?

Stannous Fluoride and 8% Arginine & calcium carbonate.

Professionally Applied Desensitizing Products are recommended for what level of sensitivity?

Moderate to severe sensitivity.

What is the mechanism of action for NaF Varnish when professionally applied?

It temporarily occludes dentinal tubules.

What is the most common procedure used in periodontal surgery for the management of DH?

A connective tissue graft.

List four categories of professionally applied desensitizing agents (other than varnishes, restorations, or surgery).

Precipitants (e.g., Arginine/Calcium carbonate, CPP-ACP, CSP), Primers containing hydroxyethyl methacrylate (HEMA), Polymerizing agents, Iontophoresis, and Lasers.

When might restorations be placed in DH management?

They are placed over exposed dentin, especially when esthetics are a concern.

When might root canal therapy or extraction be necessary in DH management?

In extreme cases.