DENTIN HYPERSENSITIVITY :It is characterized by short , sharp pain arising from exposed dentin in response to stimuli typically thermal , chemical, osmotic, evaporative, tactile and which cannot be ascribed to any other form of dental defect or pathology.

ETIOLOGY :

ENAMEL LOSS :

• Occlusal wear
• Toothbrush abrasion
• Dietary erosion
• Abfraction
• Parafunctional habits

CEMENTAL LOSS:

• Gingival recession
• Periodontal disease
• Root planing
• Periodontal surgery

DEVELOPMENT OF DENTIN HYPERSENSITIVITY

There are two phases in the devlopment of dentin hypersensitivity .

1. LESION LOCALISATION : This requires exposure of dentin .Lesion localisation occurs by gingival recession , abrasion , erosion , etc.
2. LESION IRRITATION: This requires removal of the cementum or smear layers . This occurs due to periodontal procedures or by the action of abrasive or erosive agents.

Several theories have been put forward to explain the dentin hypersensitivity.

1. Direct nerve innervation theory
2. Odontoblast deformation theory / transducer phenomenon
3. Hydrodynamic theory : most accepted theory .

CLINICAL FEATURES:

1. Pain : short, sharp , rapid in response to external stimuli
2. Pain may emanate to single or multiple tooth.
3. Intensity of pain may range from mild to moderate .
4. presence of gingival recession / cemental loss.
5. The clinical symptoms are similar tot hat of acute reversible pulpitis .
6. Most commonly affected teeth : buccal surfaces of premolars and facial surfaces of incisors.

DIAGNOSIS :

CASE HISTORY :

1. The history and nature of pain
2. The number and location of sensitive teeth.
3. The intensity of pain.
4. The stimuli which initiate the pain
5. The frequency and duration of pain.

CLINICAL EXAMINATION :

1. Evidence of dentin exposure ( gingival recession, loss of enamel )
2. Sensitivity or pain on tactile examination of the suspected teeth .
3. Percussion sensitivity
4. Pain lingering after the stimulus is removed .
5. Vitality tests .
6. Radio-graphic examination .
7. Signs of fracture , leaky or poor restorations.

PREVENTION :

1. Diet counselling
2. Correction of brushing techniques .
3. Care during operative procedures.
4. Care during periodontal procedures like scaling and root planing .

MANAGEMENT :

DESENSITIZATION BY OCCLUDING DENTINAL TUBULES :

1. Formation of smear layer over exposed dentin
2. Use of topical agents to occlude the exposed dentinal tubules: calcium hydroxide paste, silver nitrate, fluorides, potassium oxalate, varnishes , dentin adhesives.
3. Placement of restorations: GIC and composite resins.
4. Use of lasers :CO2 lasers , Nd: YAG, Er:YAG lasers

DESENSITIZATION BY BLOCKING PULPAL SENSORY NERVES

1. POTASSIUM NITRATE TOOTHPASTES.: Potassium ions can easily pass through dentin to pulp , here they block the depolarization of the sensory nerve endings present close to the odontoblasts , thus preventing the transmission of impulses to the brain .

REFERENCE: STURDEVANTS 7TH EDITION

Written by- Dr. Urusa I Inamdar

Reference:

Grossman’s Endodontic Practice (13th edition)

One of the basic goals of conservative dentistry is to preserve the health of the pulp as it is subjected to many insults such as caries, trauma, operative procedures, restorative materials.

Pulpal irritants can be classified as microbial, mechanical, chemical, thermal.

NEED FOR PULP PROTECTION

• mechanical protection during restorative procedures.
• barrier to the chemical components of restorative materials.
• thermal protection against temperature changes in the pulp .
• electrical protection against galvanic currents.
• pulp medication to allow the recovery of the pulp in case of deep defects.
• adequate seal at the restorative -tooth interface against bacterial ingress.

PULP PROTECTIVE AGENTS

CLASSIFICATION

• cavity sealers- cavity varnish, resin bonding agents.
• cavity liners
• cavity bases

CAVITY SEALERS: These are materials that provide a protective coating to the walls of the prepared cavity .They are applied to all the walls of the cavity and seal the interface between the restoration and the tooth . Eg: cavity varnish and resin bonding agents.

CAVITY VARNISH: A varnish is a natural gum or a synthetic resin dissolved in an organic solvent . Once it is applied to tooth surface the organic solvent evaporates leaving behind a protective film. Varnish is used beneath amalgam restoration to seal the amalgam tooth interface until corrosion product form to reduce the marginal gap. Thickness of varnish is 2-5 micrometer . They does not provide thermal protection and are contraindicated for GIC .

RESIN BONDING AGENTS: Currently the best method for the bonding composite resin to the tooth structure. Apart form adhesion it also provides cavity sealing. They are also employed for bonding amalgam restorations to reduce micro leakage .

CAVITY LINERS :They are used to provide a barrier against the passage of irritants from the cements or other restorative materials and to reduce the sensitivity of freshly cut dentin . They are usually suspension of calcium hydroxide in a volatile solvent . TYPES : TYPE III GIC , TYPE IV ZOE . Thickness is 0.5 mm

CAVITY BASES: A base is a layer of cement placed beneath the permanent restoration to encourage recovery of the injured pulp and to protect it against numerous types of insults. TYPES : high strength bases and low strength bases .

HIGH STRENGTH BASES provide thermal protection for pulp and mechanical support for the restoration . Eg : zinc phosphate , zinc polycarboxylate, RMGI, GIC

LOW STRENGTH BASES have minimum strength and rigidity . act as a barrier to irritation , chemicals and to provide therapeutic effect to pulp.Eg calcium hydroxide . ZnOE .

REFERENCE : STURDEVANT’S 7TH EDITION

ASHTINDER 🖊