TEETH HYPERSENSITIVITY . What is Teeth Hypersensitivity

. Etiological factors

. Diagnosis

. Management Definition

. An exaggerated response to a sensory stimulus that usually causes no response in normal healthy teeth

. That stimulus can be tactile, thermal, electrical or chemo-osmotic stimulation • Prevalence: - Between 60 and 98% in patients with periodontitis.

- Transient hypersensitivity may occur after periodontal procedures as (deep scaling, root planning or gingival surgery).

- May occur after teeth whitening or restorative procedures.

- Peak age (20-40 y.) - females ˃ males Mechanism of dentin hypersensitivity: 1- neural theory 2- odontoblastic trasduction theory 3- hydrodynamic theory

ETIOLOGICAL FACTORS I) Preoperative etiological factors: a) Bacterial b) Chemical - Osmotic c) Mechanical d) Thermal e) Idiopathic

II) Post operative (Iatrogenic): a) Cavity preparation. b) Restorative phase and restorations. c) Vital teeth bleaching. I) Preoperative etiological factors: a) Bacterial b) Chemical - Osmotic c) Mechanical d) Thermal e) Idiopathic

II) Post operative (Iatrogenic): a) Cavity preparation. b) Restorative phase and restorations. c) Vital teeth bleaching. Dental caries

Produces different levels of teeth hypersensitivity that is mainly related to:

. The depth of decay. . Dentin conductance. . Pain threshold of the patient himself. 1- Depth of decay:

. Caries in enamel involve no or little hypersensitivity.

. In dentin is characteristic to be short and sharp pain arising from exposed dentin in response to stimuli.

. Dull ache pain: if pulpal changes occur which might involve an irreversible pulpitis. 2-Dentin conductance Deeper in dentin and near the pulp: no of D.Ts., diameter, length, permeability and consequently the degree of hypersensitivity. I) Preoperative etiological factors: a) Bacterial b) Chemical - Osmotic c) Mechanical d) Thermal e) Idiopathic

II) Post operative (Iatrogenic): a) Cavity preparation. b) Restorative phase and restorations. c) Vital teeth bleaching. Erosion:

. The dissolution of teeth by acids which are not of bacterial origin. . Acids or osmotic agents like sugar when adhere to the margins of leaky restoration or exposed dentin, it will cause flow of dentinal fluid hypersensitivity.

I- Extrinsic erosion

Citrus fruits.

Pickled food.

Fruit juice.

Carbonated drinks. I- Extrinsic erosion

Wines.

Vitamin C.

Mouth rinses with low PH.

Bleaching agents. II- Intrinsic erosion

. Results from gastric reflux as in Hiatus hernia, alcoholism, eating disorders like bulimia nervosa . In case of intrinsic erosion the palatal aspect of the upper anterior teeth and the occlusal and buccal surfaces of the lower posterior teeth are primarily affected. Intrinsic erosion as a result of gastric reflux and vomiting Intrinsic erosion as a result of eating disorder

I) Preoperative etiological factors: a) Bacterial b) Chemical - Osmotic c) Mechanical d) Thermal e) Idiopathic

II) Post operative (Iatrogenic): a) Cavity preparation. b) Restorative phase and restorations. c) Vital teeth bleaching. Mechanical factors i) Attrition ii) Bruxism iii) Abrasion iv) Abfraction v) Gingival recession vi) Cracked tooth syndrome vii) Trauma 1-Attrition

Wear at sites of direct contact between teeth. Attrition is associated with normal occlusal function and can be aggravated by habits or parafunctional activities which is known as bruxism 2-Bruxism

The bruxism results in hypersensitivity to heat and cold, fractured teeth and fillings, myofacial pain, headache, stiffness and pain in the joints and earache. 3-Abrasion

The wear of teeth caused by objects other than teeth (toothbrush, tooth paste, pipe smoking…) 4- Abfraction

The wear of teeth at the cervical portion as a result of occlusal loading that leads to cuspal flexture 5-Gingival recession

. Result from malbrushing, malocclusion, excessive brushing and flossing. . Results in exposure of cementum which will lead to exposure of dentin and hypersensitivity 6- Cracked tooth syndrome:

• Incomplete fracture of the teeth

• Involving dentin only or extending to pulp

• Resulted in teeth hypersensitivity with biting relieved with releasing.

• Can happen in sound teeth especially upper premolars (steepness), or most commonly in teeth that is restored with big restoration 7- Trauma

Fracture of E. & D. Fracture of root fracture of enamel I) Preoperative etiological factors: a) Bacterial b) Chemical - Osmotic c) Mechanical d) Thermal e) Idiopathic

II) Post operative (Iatrogenic): a) Cavity preparation. b) Restorative phase and restorations. c) Vital teeth bleaching. . Reversible hypersensitivity It subside by treating the exposed dentin

. Irreversible hypersensitivity It might require root canal treatment or even extraction of the teeth in some severe cases.

I) Preoperative etiological factors: a) Bacterial b) Chemical - Osmotic c) Mechanical d) Thermal e) Idiopathic

II) Post operative (Iatrogenic): a) Cavity preparation. b) Restorative phase and restorations. c) Vital teeth bleaching. i. Cutting instruments

. Rotary instruments produce more heat generation than the hand instruments.

. Dull instruments require higher pressure and subsequently more heat generation

. Heat can destruct pulpal tissue, coagulate protoplasm and even burn dentin and hence proper cooling is mandatory. ii. Instrumentation pressure: Cause heat generation and might cause actual aspiration of odontoblastic nuclei into the tubules

iii. Vibration: Cause a rebound response as a result of using eccentric burs, which can result in necrotizing effects on dentin

iv. Dentin Desiccation: Can result from: - Heating of dentin during cutting. - Use of chemicals to sterile the cavity. - Use of air as a coolant for final cavity toilet.

v. Actual cutting in dentin: Every square millimetre of dentin cut exposes 30,000 to 45,000 dentinal tubules with resultant fluid movement in each one of them stimulating nerve damage. I) Preoperative etiological factors: a) Bacterial b) Chemical - Osmotic c) Mechanical d) Thermal e) Idiopathic

II) Post operative (Iatrogenic): a) Cavity preparation. b) Restorative phase and rest. c) Vital teeth bleaching. Restorative phase and restorations

*Polymerization shrinkage *Undercured resin

*Microleakage *Inadequate liner and/or base

*Fractured restoration *Cracked tooth

*Galvanism *Finishing Procedures

*Faulty occlusal and/or proximal relationship

*Gingival reaction to the rest. procedure and rest.

*Pulpal reaction to the rest procedure and rest.

*Local anesthesia *Barodontology

Restorative phase and restorations

1) Polymerization shrinkage  Polymerization shrinkage results in stresses at the interface resulting in microleakage, microcracks and secondary caries.  C factor. 2) Undercured resin

 Incompletely cured inner layer, results in marginal fracture, open margin and chemical toxicity. Restorative phase and restorations

3) Microleakage:

Ingress of fluids and microorganisms cause dentinal hypersensitivity due to dentinal fluid movements.

4) Inadequate protection: Metallic restoration cause hypersensitivity specially in first few days. Pain is elicited with hot or cold application and relieved with removal of the stimulus. Restorative phase and restorations

5) Fractured restoration: Exposed dentin, recurrent caries and dentin hypersensitivity.

6) Cracked tooth: Sharp pain on biting and eating citrus fruits, Large restorations and restorations without cusp protection . Restorative phase and restorations

7) Galvanism

Hypersensitivity is usually felt in tooth containing the rest. with the lower potential i.e: Amalgam.

The degree of hypersensitivity depends on: 1- Difference in electrical potential. 2- Electrical resistance of dentin. 3- Presence and thickness of base. 4- Current intensity. 5- Pulpal condition and patient threshold. Restorative phase and restorations

8) Faulty occlusal and/or proximal relationship

 Occlusal contact if high will affect the periodontal ligament and lead to sensitivity with bite and/ or mobility.

 Proximal contact if tight will result in excessive pressure that might result in pain and interproximal bone resorption and damage of the supporting structure. Restorative phase and restorations

9) Finishing Procedures  Might lead to heat generation.  Cervical finishing might lead to scratch or cementum loss.  Over carving leads to exposure of dentin 10) Barodontology  Expansion of air voids under or within a restoration or gases in a non-vital teeth in aeroplane.  Voids may be due to: inadequate condensation. Restorative phase and restorations

11) Gingival reaction:  Retraction cord and chemical tissue packs.  Improperly contoured or overhanging temporary dressing.  Overcontoured permanent restorations.  Undercontoured restorations will contribute to mechanical trauma of the free gingiva.  Excess cementing media. Restorative phase and restorations

12) Pulpal reaction:

A direct pulp Pulp exposure capping is followed by a If considered direct pulp hypersensitivity successful if the capping might remains for tooth is a initiate several weeks symptomatic hyperemia the root canal and gives a which can lead treatment is positive vitality to RCT. recommended. test from 3-6 months later. Restorative phase and restorations

13) Local anesthesia: Sometimes soreness occurs at the site of injection as a result of haematoma and or infection. Beside discoloration, the area is usually tender. I) Preoperative etiological factors: a) Bacterial b) Chemical - Osmotic c) Mechanical d) Thermal e) Idiopathic

II) Post operative (Iatrogenic): a) Cavity preparation. b) Restorative phase and rest. c) Vital teeth bleaching. Vital teeth bleaching

 Bleaching might cause mild tooth sensitivity to temperature changes and local oral mucosal irritation  Sensitivity depends mainly on the peroxide concentration and the patient threshold.  Peroxides pass throught E. & D. to pulp causing reversible pulpilits Diagnosis

. History

. Clinical exam

. Radiographic exam

. Differential diagnosis 1- History

. Describition of pain as: onset, duration, stimuli, spontaneity, intensity and factors that relief the pain

. Subjective evaluation (symptoms): * verbal rating scale, which is a 4 scale grading pain as slight, moderate, severe and agonizing

1- History

* Visual analogue scale is a line of 10cm in length the extremes of the line represent from no pain and till the most sever pain

* McGill word descriptors by answering a pre prepared questionnaire 2- Clinical examination

. Mechanical stimulus: Prob, scaler . Chemical (osmotic) stimulus: Sodium chloride, sucrose, glucose and calcium chloride

. Electric stimulus: Electrical pulp tester 2- Clinical examination

. Evaporative test: Air blast,

. Thermal stimulus: Ethyl chloride, ice stick It involves: *percussion *probing *trans-illumination *Magnification & others to detect the cause of the problem. 3- Radiographic examination

*To examine the bone, root and surrounding structure to confirm the diagnosis to exclude any other causes. 4- Differential diagnosis:

. Dentin hypersensitivity is diagnosed by exclusion, so all the other factors should be ruled out.

. From the diagnosis we can point the aetiological factor and treat the source of the problem MANAGEMENT

I) Natural dentin desensitization

II) Management of the etiological factors

III) Home care

IV) In office treatment I) Natural dentin desensitization

A- Dentin sclerosis: It involves deposition of minerals within tubules that results in a thicker layer of peritubular dentin, this process eventually results in a smaller tubule diameter, less permeable and less able to transmit stimuli. I) Natural dentin desensitization

B- Secondary dentin: Secondary dentin develops after the tooth root is formed, it is secreted slowly on the floor and roof of the D pulp results in decrease in the size of the pulp P chamber. I) Natural dentin desensitization

C- Tertiary dentin: Tertiary dentin or the reparative dentin is formed after the exposed dentin P has been traumatized by a D stimulus, this natural process decrease the permeability of dentin. I) Natural dentin desensitization

D- Smear layer: It plugs the dentinal tubule orifices with S debris that consists of dental shavings, tissue debris, odontoblastic processes and microbial D elements.. I) Natural dentin desensitization

E- Calculus:

It provides a protective coating to cover dentin from stimuli. Usually sensitivity occurs immediately after removal of heavy calculus which subside naturally within 2 weeks.

2- Management of etiological factors:

It is important to identify these factors so that prevention can be included in the treatment plan before starting the Active management of Dentin hypersensitivity which usually involve a combination of home care and in-office therapies 3- Home care

. Desensitizing toothpastes / dentifrices.

. Toothbrush and toothpaste application.

. Mouthwashes and chewing gums.

. Dietary Modifications.

. Management of parafunctional habits.

Desensitizing tooth pastes

 It contains potassium nitrate, which calms the nerve endings inside the dentine, relieving the pain of sensitive teeth.  Sodium fluoride, which helps prevent tooth decay and protects against acid erosion Toothbrush and toothpaste application

Soft or ultrasoft manual toothbrush with soft end rounded bristles

Lowers the risk of gingival recession and abrasion of exposed cementum and dentin. Toothbrush and toothpaste application

With powered toothbrush less pressure is required on the teeth, they require a light grasp to remove plaque. Mouthwashes and chewing gums

 Potassium nitrate  Sodium fluoride  Potassium citrate  Sodium fluoride Dietary Modification . Reduce acidic food and drinks.

. Avoiding brushing immediately after ingestion of acidic food.

. Drinking milk or water after consuming an acidic diet.

Management of parafunctional habits

Parafunctional habits can result in:  bruxism.  Teeth flexure.  Abfractions.

N.B.: Treating the cause as malocclusion, occlusal prematuraty or stress. In office treatment

. Fluoride: sodium fluoride and stannous fluoride can reduce dentin sensitivity. Fluorides decrease the permeability of dentin in vitro, possibly by precipitation of insoluble calcium fluoride within the tubules. Ionto-phoresis

Uses electricity to enhance diffusion of ions into the tissues. Dental iontophoresis is used most often in conjunction with fluoride pastes Potassium nitrate

• Potassium nitrates gels at 5% and 10% are effective in reducing dentin hypersensitivity.

• Potassium nitrate does not reduce dentin permeability but do reduce the nerve excitability. Oxalates

Oxalate products reduce dentin permeability and occlude tubules.

D/SENSE® CRYSTAL, a Super Seal®, a water- one step, dual action based potassium oxalate desensitizer and cavity desensitizer liner. Calcium phosphates

Calcium phosphates occlude dentinal tubules and decrease dentin permeability. NovaMin

. NovaMin: is bioactive glass . It consists of 45% SiO2, 24.5% Na2O, . 24.5% CaO and 6% P2O5 . it delivers an ionic form of calcium, phosphorus, silica, and sodium which are necessary for bone and tooth mineralization . The ions form hydroxyapatite crystals, a form of hard and strong mineral in teeth and blocks the open dentin tubules Casein Phosphopeptides

. It is a water based topical cream, sugar free with bioavailable calcium and phosphate.

. It provides extra teeth protection and neutralize acids from acidogenic bacteria and from other external and internal acid sources. Adhesives and resins

. Including varnishes, bonding agents and restorative materials.

. To occlude tubules in hypersensitive dentin. Lasers

. ND(YAG) laser, ER:YAG laser and WaterLase all reduce Dentin hypersensitivity.

. The effectiveness of lasers for treating dentine hypersensitivity . varies from 5 to 100 percent, depending on the type of laser and the treatment parameters.

Extensive treatment

. Crown and bridge

. Root canal treatment

. Or even extraction

Teeth Hypersensitivity 1

TEETH HYPERSENSITIVITY Introduction: Teeth hypersensitivity is an exaggerated response to a sensory stimulus that usually causes no response in normal healthy teeth. As a source of chronic irritation, teeth hypersensitivity affects eating, drinking, and breathing. Hypersensitive teeth are characterized by transient pain in response to evaporative, tactile, thermal, electrical or chemo-osmotic stimulation of exposed dentin in teeth where no other defects or pathology exist. Aetiology of teeth hypersensitivity I) Preoperative etiological factors: a) Bacterial b) Chemical - Osmotic c) Mechanical d) Thermal e) Idiopathic II) Post operative (Iatrogenic): a) Factors related to cavity preparation b) Factors related to restorative phase and restorations c) Factors related to vital teeth bleaching.

I) Preoperative etiological factors: a) Bacterial: Dental caries produces different levels of teeth hypersensitivity that is mainly related to 1- The depth of decay 2- Dentin conductance 3- Pain threshold of the patient himself.

Teeth Hypersensitivity 2

1- The depth of decay: A- Caries in enamel involve no or little hypersensitivity, B- In dentin is characteristic to be short and sharp pain arising from exposed dentin in response to stimuli, C- Dull ache pain if pulpal changes occur which might represent an irreversible pulpitis . 2- Dentin conductance : Greater degree of sensitivity happens when dental caries passes the DEJ. as caries penetrates further into the tooth, sensitivity lessens until pulp becomes involved . Deeper in dentin and near the pulp, the number of dentinal tubules is higher, the bigger the diameter of the dentinal tubules, the shorter their length, the higher the permeability of the dentinal fluids and consequently the higher the degree of hypersensitivity.

b) Chemical-Osmotic: Erosion is defined as the dissolution of teeth by acids which are not of bacterial origin. When an acid or an osmotic agent like sugar adhere to the margins of leaky restoration or exposed dentin that will affect the flow of dentinal fluid and result in hypersensitivity. Erosion can be of Extrinsic or Intrinsic origin . Teeth Hypersensitivity 3

Extrinsic erosion results of exposure to extrinsic food, fluid or agents, such as citrus fruits, pickled food, fruit juice, carbonated drinks, wines, ciders, vitamin C, some mouth rinses with low PH and bleaching agents especially those delivered in a vacuum formed trays for In home applications . Intrinsic erosion may result from gastric reflux as in Hiatus hernia, alcoholism, eating disorders like bulimia nervosa (60). In case of intrinsic erosion the palatal aspect of the upper anterior teeth and the occlusal and buccal surfaces of the lower posterior teeth are primarily affected.

c) Mechanical i) Attrition: Is defined as wear of teeth at sites of direct contact between teeth. Attrition is associated with occlusal function and can be aggravated by habits or parafunctional activities which is known as bruxism .

ii) Bruxism: The aetiology of bruxism is unknown but it could be associated with:  Sleep disorders as obstructive sleep apnea and Snoring.  Malocclusion  High consumption of alcohol and heavy smoking  Stress, digestive problems.  Disorders as Huntington and parkinson’s diseases  Drugs as: MDMA, cocaine The bruxism results in hypersensitivity to heat and cold, fractured teeth and fillings, musculofacial pain and headache, stiffness and pain in the joints and earache. Teeth Hypersensitivity 4

iii) Abrasion: It is defined as the wear of teeth caused by objects other than other teeth such as tooth brush/toothpaste abrasion, scaling and root planning and pipe smoking . iv) Abfraction: It is defined as the wear of teeth at the cervical portion as a result of occlusal loading that leads to cuspal flexure, this in turn results in compressive and tensile stresses at the cervical fulcrum area of the teeth with the resultant weakness and gradual loss of the cervical portion. v) Gingival recession: It may result from tooth brush abrasion, malocclusion, excessive brushing and flossing. Gingival recession results in exposure of cementum which less resistant to abrasion and acids than enamel, that consequently will lead to exposure of dentin and hypersensitivity . vi) Cracked tooth syndrome: It is defined as incomplete fracture of the vital teeth, can be involved in dentin only or extending to the pulp. Cracked tooth syndrome resulted in Teeth hypersensitivity with biting relieved with releasing the bite. It might involve severe spontaneous pain in case of pulp involvement, also can happen in sound teeth especially upper premolars, or most commonly in teeth that is restored with big restoration or direct gold . vii) Trauma Can involve fracture of enamel only with little or no sensitivity, enamel and dentin with moderate to sharp pain with stimuli typically evaporative, thermal, mechanical (tactile) or osmotic, pulp involvement with dull ache spontaneous pain, or fracture of the root which will result in tenderness to touch or percussion. The trauma Teeth Hypersensitivity 5

might result in no damage at all but tenderness to touch as a result of trauma to the periodontal ligament that can subside later. d) Thermal and idiopathic: Which can result in reversible hypersensitivity that subside by treating the exposed dentin and preventing the cause, and irreversible pulpal damage. II) Post operative (Iatrogenic): a) Factors related to cavity preparation: i) Type of cutting instruments: Rotary instruments produce more heat generation than the hand instruments. Dull instruments might require higher pressure for cutting which will result in more heat generation. Heat can destruct pulpal tissue, coagulate protoplasm and even burn dentin. Proper cooling is mandatory with all rotary instruments. ii) Instrumentation pressure: Cause heat generation and might cause actual aspiration of odontoblastic nuclei into the tubules. iii) Vibration: Cause a rebound response as a result of using eccentric burs, which can result in necrotizing effects on dentin. Rebound response appears microscopically as a limited area of necrosis at an area remote from the cut dentinal tubules. iv) Dentin Desiccation: Can result from heating of dentin during cutting, use of chemicals to sterile the cavity or use of air as a coolant for final cavity toilet. v) Actual cutting in dentin: Every square millimetre of dentin cut exposes 30,000 to 45,000 dentinal tubules with resultant fluid movement in each one of them stimulating nerve damage. Teeth Hypersensitivity 6

b) Factors related to restorative phase and restorations i) Polymerization shrinkage The polymerization shrinkage results in stresses at the composite/tooth interface resulting in microleakage, micro cracks or deformation of tooth structure. Microleakage can result in secondary caries formation and the consequent teeth hypersensitivity. Stresses are greatest in cavities with high ratio of C factor (ratio of bonded surfaces to unbonded surfaces), decreasing C factor will result in decreasing stresses from polymerization shrinkage.

ii) Undercured resin Can result from a light source of inadequate intensity, or not close enough to the resin, or a light which is attenuated by passage through tooth structure or restoration. That results in a well cured surface covering incompletely cured layer, which will result in marginal fracture, open margin and chemical toxicity from the monomers or the bonding agent.

iii) Microleakage Any restoration though exhibits clinical satisfactory adaptation, shows some leakage. The ingress of fluids and micro organisms can be the cause of dentinal hypersensitivity in addition to the fluid movements within the dentinal tubules.

iv) Inadequate liner and/or base Any metallic restoration conducts thermal changes to the underlying dentin and pulp which can cause hypersensitivity specially in the first few days postoperatively. The pain is elicited after heat or cold application and Teeth Hypersensitivity 7

relieved with removal of the stimulus. The greater the temperature gradient,the more painful and lasting the stimulus. The dentin effectiveness as a thermal insulator depends on its thickness. v) Fractured restoration Exposes dentin, admits oral fluids and microbes which will cause recurrent caries and dentin hypersensitivity. vi) Cracked tooth Pain on biting and eating citrus fruits, this sharp pain will disappear when pressure is released. Commonly happens in teeth with large restoration and cast restoration without proper consideration for cusp protection . vii) Galvanism When two dissimilar metallic restorations brought into contact the current will pass between them and a galvanic stimuli will be generated. Hypersensitivity is usually felt in the tooth containing the restorative with the lower potential, i.e: Amalgam . The degree of hypersensitivity will depend on some factors as: The difference in the electrical potential between the dissimilar metals, the electrical resistance of dentin and soft tissues, presence of base and its thickness, the current intensity, the pulpal condition and the patient threshold. viii) Faulty occlusal and/or proximal relationship Occlusal contact if high will affect the periodontal ligament and lead to sensitivity with bite and/ or mobility. Proximal contact if tight will result in excessice pressure that might result in pain and interproximal bone resorption and damage of the supporting structure. Teeth Hypersensitivity 8

Proximal contact if light will result in food impaction interproximally and gingival inflammation, which if neglected will result in damage of the supporting structure. ix) Finishing Procedures Over finishing of restoration might result in heat generation which will lead to hypersensitivity. Finishing of the restoration cervically might lead to scratch or total loss of the cemetum in this area. Over carving of Amalgam restoration or uncovering the exposed dentin by cement in case of indirect restoration will result in teeth hypersensitivity. x) Barodontology It is the teeth hypersensitivity that occurs with reduced pressure, which occur during Aviation (in aeroplane). This could be due to expansion of air voids under a restoration, gases in a non-vital or due to expansion of air voids incorporated into the restoration during its application. Voids may be due to: inadequate condensation. xi) Gingival reaction to the restorative procedure and restoration  Retraction cord and chemical tissue packs used before the elastic impression taking, can result in soft tissue irritation.  Improperly contoured or overhanging temporary dressing can result in gingival irritation.  Overcontoured permanent restorations will contribute to poor gingival health by preventing through cleaning of the area.  Undercontoured restorations will contribute to lack of protection of the gingival crevice and mechanical trauma of the free gingiva. Teeth Hypersensitivity 9

 Cementing media left in the crevice may cause gingival irritation that ranges from mild to severe inflammation..

xii) Pulpal reaction to the restorative procedure and restoration. The pulpal reaction to a restorative procedure is difficult to determine, sometimes even with a conservative cavity preparation, the pulp experiences a degree of degeneration. Deep restoration may cause the pulp to devitalize many years later. A pulp exposure followed by a direct pulp capping might initiate an immediate hyperemia which can lead to root canal treatment. Generally if the hypersensitivity remains for several weeks the root canal treatment is recommended. A direct pulp capping is considered successful if the tooth is a symptomatic and gives a positive vitality test from 3-6 months later.

xiii) Local anesthesia Sometimes soreness occurs at the site of injection as a result of haematoma and or infection. Beside discoloration the area is usually tender.

c) Factors related to vital teeth bleaching. Both office and home bleaching procedures may induce discomfort in some patients. The principal complaints are mild tooth sensitivity to temperature changes and local oral mucosal irritation. Bleaching sensitivity is commonly associated with Carbamide peroxide vital teeth bleaching (32) due to the by products of 10% carbamide peroxide readily pass through the enamel and dentin into the pulp in a matter of minutes. Sensitivity takes the form of reversible pulpitis caused from the dentin fluid flow and pulpal contact of the material. Sensitivity Teeth Hypersensitivity 10

can happen in any form of the bleaching agents, it depends mainly on the peroxide concentration and the patient threshold.

Natural dentin desensitization (22) Some natural processes can improve hypersensitivity overtime, even without treatment intervention. These include sclerosis of dentin, deposition of secondary and tertiary dentin, creation of a smear layer and calculus formation on the surface of the dentin. Sclerosis of dentin involves deposition of minerals within tubules that results in a thicker layer of peritubular dentin, this process eventually results in the tubule becoming smaller in diameter, making it less permeable and less able to transmit stimuli. Secondary dentin develops after the tooth root is formed, it is secreted slowly on the floor and roof of the pulp results in decrease in the size of the pulp chamber. Tertiary dentin or the reparative dentin is formed after the exposed dentin has been traumatized by a stimulus, this natural process decrease the permeability of dentin. Teeth Hypersensitivity 11

The smear layer is described as a combination of organic and inorganic debris, the smear layer plugs the dentinal tubule orifices with debris that consists of dental shavings, tissue debris, odontoblastic processes and microbial elements. Calculus formation provides a protective coating to cover dentin from stimuli. Usually sensitivity ocurrs immediately after removal of heavy calculus which subside naturally within 2 weeks.

Management of postoperative dentin Hypersensitivity Diagnosis:Which includes: History taking, clinical examination and differential diagnosis, assessment of the etiological factors and management of the etiological factor after accurate diagnosis a) History: The patient is asked to describe the characteristics of pain as: onset, duration, stimuli, spontaneity, intensity and factors that relief the pain. After careful listening to the pt, the dentist need to gather the information related to Subjective information (symptoms) and the objective information (Signs) through clinical examination. Subjective evaluation could be carried out by a verbal rating scale, which is a 4 scale grading pain as slight, moderate, severe and agonizing, by Visual analogue scale is a line of 10cm in length the extremes of the line represent the limits of pain experienced by the patient from no pain and till the most sever pain and the McGill word descriptors by answering a pre prepared questionnaire. b) Clinical and Radiographic examination: it is the objective evaluation of clinical signs using:) Teeth Hypersensitivity 12

- Mechanical stimulus: Probe, scaler, constant pressure probe and Yeaple pressure stimulators. - Chemical (osmotic) stimulus: Sodium chloride, sucrose, glucose and calcium chloride. - Electric stimulus: Electrical pulp tester and dental pulp stethoscope. - Evaporative test: air blast, Air jet stimulator - Thermal stimulus: Ethyl chloride, ice stick and heat thermoelectric devices. It involves clinical examination of teeth by percussion, probing, trans- illumination and other methods to detect the cause of the problem as caries, fractured restoration, cracked tooth or others. c) Radiographic examination to examine the bone, root and surrounding structure to confirm the diagnosis. d) Differential diagnosis: Dentin hypersensitivity is diagnosed by exclusion (33), so all the other factors should be ruled out. From the diagnosis we can point the aetiological factor and treat the source of the problem. Techniques to Reduce Preoperative Hypersensitivity . Minimize preparation trauma . Maximize dentin seal using dentin bonding agents . Avoid : – inadequate isolation – overetching, dessicating demineralized dentin – inadequate priming, primer solvent not evaporated – inadequate adhesive placement, adhesive not photopolymerized . Ensure temporary crown is well-fitting . Ensure correct occlusal contacts

Teeth Hypersensitivity 13

Techniques to Reduce Preoperative Hypersensitivity I) Home care: Desensitizing toothpastes / dentifrices Potassium salts Toothbrush and toothpaste application: Practitioners should educate patients on how to use dentifrices and monitor their toothbrushing techniques. Use of a soft or ultrasoft manual toothbrush with soft end rounded bristles lowers the risk of gingival recession and abrasion of exposed cementum and dentin. With powered toothbrush less pressure is required on the teeth, they require a light grasp to remove plaque. Dentifrices should be applied by toothbrushing. There is no evidence to suggest that finger application of the paste increases effectiveness. Many patients habitually rinse their mouths with water after toothbrushing. Rinsing with water may cause the active agent to be diluted and cleared from the mouth and, thus, reduce the efficacy of the caries-reducing effect of fluoride toothpastes. Mouthwashes and chewing gums: Studies have found that mouthwashes containing potassium nitrate and sodium fluoride, potassium citrate or sodium fluoride or a mixture of fluorides) can reduce Dentine hypersensitivity. Dietary Modifications: Controlling the consumption of acidic food and drinks such as citrus fruits, wine, pickled foods and carbonated beverages. Avoiding brushing immediately after ingestion of acidic food, as it may accelerate the combined effect of abrasion and erosion, rinsing with water is recommended before brushing. Additional recommendations includes drinking something neutral or alkaline such as milk or water after consuming an acidic diet, Sipping acidic drinks through a straw and reducing the quality and frequency of acid intake.

Teeth Hypersensitivity 14

Management of parafunctional habits: Parafunctional habits can result in bruxism, teeth flexure or abfractions that lead to hypersensitivity, treating the cause as malocclusion, occlusal prematuraty or stress is recommended first, then preventing further tooth structure damage by conservative measures as night guard and fluoride. If home care fails to reduce Dentine hypersensitivity compared with baseline levels, the next level of treatment, an in-office method, should be started. ii) In office treatment: Fluoride: Fluorides such as sodium fluoride and stannous fluoride can reduce dentin sensitivity.) Fluorides decrease the permeability of dentin in vitro,) possibly by precipitation of insoluble calcium fluoride within the tubules. Ionto-phoresis: This procedure uses electricity to enhance diffusion of ions into the tissues. Dental iontophoresis is used most often in conjunction with fluoride pastes or solutions ) and reportedly reduces Dentin hypersensitivity. Potassium nitrate: Potassium nitrate, which usually is applied via a desensitizing toothpaste, also can reduce dentin sensitivity when applied topically in an aqueous solution or an adhesive gel. Potassium ions do reduce nerve excitability in animal models. Oxalates: Oxalate products reduce dentin permeability and occlude tubules more consistently in laboratory studies than they do in clinical trials. Calcium phosphates: Calcium phosphates may reduce dentin sensitivity effectively. Calcium phosphates occlude dentinal tubules and decrease dentin permeability. Teeth Hypersensitivity 15

Orajel Tooth Desensitizer : treats pain from sensitive teeth by blocking dentinal tubules preventing excitation of the tooth nerve. NovaMin: is the brand name of a particulate bioactive glass that is used in dental care products. It consists of 45% SiO2, 24.5% Na2O, 24.5% CaO and 6% P2O5. it delivers an ionic form of calcium, phosphorus, silica, and sodium which are necessary for bone and tooth mineralization. NovaMin can be used an effective, non-toxic alternative to fluoride. Casein Phosphopeptides: It is a water based topical cream, sugar free with bioavailable calcium and phosphate, in the form of CPP-ACP (casein phosphopeptides- amorphous calcium phosphates. Recent studies reported that it provides extra teeth protection and neutralize acids from acidogenic bacteria and from other external and internal acid sources. Adhesives and resins: Because many topical desensitizing agents do not adhere to the dentin surface, their effects are temporary. Stronger and more adhesive materials offer improved and longer-lasting desensitization. In the 1970s, Lasers:The effectiveness of lasers for treating dentine hypersensitivity varies from 5 to 100 percent, depending on the type of laser and the treatment parameters.