Pulpal Diseases : A Seminar

INTRODUCTION

‘‘The pulp lives for the dentin and the dentin lives by the grace of the pulp. Few  marriages in nature are marked by a greater affinity.’’ Alfred L. Ogilvie

The pulp is a formative organ of tooth, secondary dentin after tooth eruption and reparative dentine in response to stimulation as long as an organ with little resistance. Its resistance depends on cellular activity, nutritional supply, age and other metabolic and physiologic parameters. The poor resistance of the pulp may be due to high plasminogen activity which rapidly breaks down the fibrin following injury. So every attempt should be made to maintain vitality of pulp and protect it from injury.

Causes of pulp diseases

•         Various causes of pulpal diseases are:

•         PHYSICAL

•         Mechanical

•         Trauma (Accidental, Iatrogenic)

•         Pathological Wear ( Attrition, Abrasion Etc)

•         Cracked Tooth Syndrome

•         Barodontalgia

•         Thermal

•         Heat From Cavity Preparation

•         Exothermic Setting Of Cements

•         Thermal Conduction Through Deeo Fillings

•         Polishing Heat

•         Electrical

•         Galvanic Current From Dissimilar Fillings

•         CHEMICAL

•         Phosphoric Acid, Acrylic Monomer Etc

•         Dental Erosion (Acids)

•         BACTERIAL

•         Toxins Assoc With Caries

•         Direct Pulp Invasion

•         Anachoresis

1. PHYSICAL CAUSES

Physical causes include Mechanical, Thermal or Bacterial injuries.

A. MECHANICAL INJURIES:

Trauma

Pathologic wear

Cracked tooth syndrome

Radiation

Restorations

A. Mechanical  Injuries

Trauma:

Although injuries may occur at any age but most likely time is during 2- 5 years.

However in adults various causes of traumatic injury to pulp may be Sports, automobile accidents, habits viz. bobby pin opening, bruxism and nail biting.

In addition certain dental procedures occassionaly injure the pulp.

 Accidental exposure of pulp,

Too rapid orthodontic movement

Rapid separation of teeth

Pins for amalgam restorations

Malleting of DFG without adequate cement base

Dehydration of pulp from prolonged blast of air, Cavit.

Pathological Wear:

The pulp may also become exposed or nearly exposed by pathological wear of teeth from either abrasion or attrition if secondary dentin is not deposited rapidly enough.

Occlusal trauma may also injure the pulp because of repeated irritation to the neurovascular bundle in periradicular area.

Cracked Tooth Syndrome:

Incomplete fractures through the body of the tooth may cause pain of apparently idiopathic origin.

Mild to excruciating pain at the initiation or release of biting pressure.

Diagnosis:

Make patient bite on cotton applicator or rubber block.

Dye, Trans illumination using fiber optic light may help in visualization.

Removal of intracoronal restoration may reveal a crack.

Sometimes even pulp may be necrotic.

Some of the cracked teeth fracture completely and patient becomes free of symptoms.

If the patient has an incomplete fracture of only enamel and dentin, a full crown restoration immobilizing the fragments may be successful.

Radiation:

Laser radiation sufficient to cause cavitation in teeth also causes severe degenerative changes in the pulp.

Pulpal reaction to fillings:

Fillings produce some reactions when they are inserted into cavities prepared in dentin.

The deeper the cavity greater is damage produced.

But in most cases pulp recovers from the injury.

Barodontolgia

Also referred to as Aerodontalgia denoting toothache occurring at low atmospheric pressure.

Usually experienced during flight or in decompressed chamber.

Commonly seen in tooth with chronic pulpitis which is asymptomatic at ground level.

Causes pain because of reduced pressure.

Lining the cavity with varnish or sub base in deep cavities prevents it.

B. Thermal Injury

The thermal causes of pulpal injury are uncommon.

Thermal Injury:

Heat from cavity preparation

Frictional heat during polishing

Heat conduction by fillings

Heat from cavity preparation:

Heat generation by bur or diamond is the chief offender.

High speed engines and carbide burs may reduce operating time but they may also accelerate pulp death if used without a coolant.

Slow speed cutting without coolant is most detrimental.

Special care must be taken while preparing large cavities or jacket crowns.

The water spray must be directed at dentin directly under the bur.

If water spray is not directed properly it might lead to burns in dentin.

Aspiration of odontoblastic nuclei occurs if water spray is inadequate.

Pulpal damage gets repaired fast when cavity is prepared under water spray.

Frictional heat during polishing

Enough heat may also be generated during polishing of a filling or during setting of cement to cause at least transient pulp injury.

Heat conduction by fillings

Metallic fillings close to the pulp without an intermediate cement base may conduct temperature changes rapidly to pulp and may eventually destroy it.

C. Electrical Changes

•         Mainly caused due to production of galvanic current.

•         Avoid placing dissimilar metallic fillings in oral cavity.

•         Place good insulating base under the fillings.

2. CHEMICAL CAUSES

•         For generations the dental profession has laboured under the misconception that most filling materials are highly toxic to the dental pulp.

•         Some properties of materials that might be capable of producing injury include :

•         Acidity

•         Absorption of water during setting

•         Heat evolved during setting

•         Poor marginal adaptation resulting in bacterial contamination.

Acid percentage in restorative materials is probably neutralised by dentin and dentinal fluid, thus  remaining dentin thickness plays a crucial role.

Placement of Zinc Phosphate at luting consistency  may have a toxic effect as diffusion barrier is extremely thin.

Acid etching causes most chemical irritation while Ca(OH)2 causes low grade pulpal irritation for dentinal bridge formation.

Eugenol from ZnOE could pass the dentinal barrier. (Ingle & Bakland, 2002)

Water absorrption by restorative materials can also cause pulpal injury. Eg: Cavit causes dessication when placed in dry cavity.

When dental materials do not provide hermetic seal, bacteria penetrates and grows beneath the restorations producing toxins which may cause pulpal injury.

Slow progressive erosion of the teeth may eventually subject the pulp to irritation and may cause permanent damage.

3. BACTERIAL CAUSES

•          Suggested by W. D. Miller in 1894.

•          Most common cause of pulp injury.

•         Bacteria may enter pulp by one of three ways

•         Direct invasion by way of the dentin (Caries, fracture of crown, exposure during excavation of caries, attrition, abrasion, erosion).

•         From extension of infection through the gingiva

•         Invasion through the blood (Infectious diseases or transient  bacteremia).

Once bacteria have invaded the pulp, the damage is always almost irreparable.

The bacteria most often recovered from pulp are Staphylococci and Streptococci.

Lactobacilli are commonly found in carious dentin but seldom found in pulp because of low degree of invasiveness.

Classification of pulpal diseases:

•         Diseases Of Pulp (Grossman)

•         Pulpitides (Inflammation)

•         Reversible

•         Symptomatic

•         Asymptomatic

•         Irreversible

•         Acute

•         Abnormally Responsive To Cold

•         Abnormally Responsive To Heat

•         Chronic

•         Asymptomatic With Pulp Exposure

•         Hyperplastic Pulpitis

•         Internal Resorption

•         Pulp Degeneration

•         Calcific

•         Others

•         Necrosis

•         Pulp Inflammation (Baume)

•         Asymptomatic

•         Symptomatic Reversible Inflammation

•         Irreversible Phase

•         Pulpal Necrosis

•         Diseases Of Pulp (Seltzer & Bender)

•         Treatable

•         Intact, uninflammed pulp

•         Transitional stage

•         Atrophic pulp

•         Acute pulpitis

•         Chronic partial pulpitis without necrosis.

•         Untreatable

•         Chronic partial pulpitis with necrosis

•         Chronic total pulpitis

•         Total pulp necrosis

•         Other Classifications of Diseases Of Pulp:

Inflammation Of Pulp

Pulpal pathosis is basically a reaction to bacteria and bacterial products.

The pulp responds to various challenges by inflammatory process.

Pulpitis may be acute or chronic, partial or total and the pulp may be infected or sterile.

Reversible Pulpitis

Definition:

It is Mild to moderate inflammatory condition of the pulp caused by noxious stimuli in which the pulp is capable of returning to the uninflammed state following the removal of stimuli.

Pain of brief duration may be produced by thermal stimuli but pain subsides as soon as stimulus is removed

Histopathology:

Ranges from hyperemia to mild to moderate inflammatory changes limited to involved area.

Microscopically Reparative dentin, Disruption of odontoblastic layer, Dilated blood vessels, Extravasation of edema fluid and inflammatory cellsare seen.

Chronic inflammatory cells are predominant.

Cause:

Trauma: From blow or disturbed occlusion.

Thermal shock: From Cavity Prep.

Dehydration of cavity:

Galvanism

Chemical stimulus: From food stuffs or dental cements

Circulatory disturbances

Local vascular congestion

Symptoms:

Characterized by sharp pain lasting but a moment.

More often by cold than hot food or beverages.

Cause of pain is generally traceable to stimulus.

Asymptomatic reversible pulpitis may result from incipient caries.

Diagnosis:

Is by study of the patient’s symptoms and by clinical tests.

Pain is sharp, lasts for few seconds and disappears when stimulus is removed.

Cold, sweet or sour usually causes it.

As pulp is generally sensitive to cold application of cold is an excellent method of locating & diagnosing.

Reversible pulpitis reacts normally to percussion, palpation and mobility tests.

Radiographic examination:

Periapical tissue is normal.

Differential diagnosis:

In reversible pulpitis, pain is generally transitory, lasting a matter of seconds whereas in irreversible pulpitis, pain may last several minutes or longer.

The patient’s description of the pain is helpful in reaching the diagnosis.

The electric pulp test uses less current than on a control tooth.

Treatment:

Prevention.

Restore incipient lesions.

Desensitize areas of cervical erosion.

Use liners and bases.

Prognosis:

Prognosis is favourable if the irritant is removed early enough; otherwise condition may develop into irreversible pulpitis.

Irreversible Pulpitis:

Definition:

It is a persistent inflammatory condition of the pulp, symptomatic or asymptomatic, caused by noxious stimuli.

Pain usually exhibited by hot or cold or occurs spontaneously.

Pain persists for several minutes to hours, lingering after removal of stimulus.

Histopathology:

Has both acute and chronic inflammatory changes in pulp.

Congested venules affecting circulation within pulp.

Necrotic areas attract PMN by chemotaxis starts acute inflammatory  reaction.

Pus formation.

Cause:

 Most common is bacterial involvement through caries.

Although other factors like chemical, mechanical or thermal can also cause irreversible pulpitis.

Reversible pulpitis may deteriorate into irreversible pulpitis.

Symptoms:

 In Early Stages :–

Paroxysm of pain caused by sudden temperature change, sweet or acidic stuff, initiated by packing of food stuff into the cavity or suction exerted by tongue or cheek.

Pain continues after cause has been removed and may come & go spontaneously

Pain is sharp, piercing or shooting.

Change in posture aggravate the pain.

Referred to adjacent areas.

In Later Stages:-

Pain is more severe and described as boring, gnawing or throbbing pain.

Pulp is covered with a layer of soft leathery decay.

Patient kept awake at night.

Increased with heat and sometimes relieved with cold, although continued cold may may intensify the pain.

Diagnosis:

Visual inspection reveals deep caries extending to the pulp covered by grayish scum like layer.

This layer is composed of food debris, degenerated PMN’s, microorganisms and blood cells.

Usually odor of decomposition present.

If the pulp is not exposed by the carious process, a pus drop can be seen when one gains access to pulp chamber.

In Early Stages: thermal test may elicit pain that persists after removal of stimulus.

In Late Stages: when pulp is exposed it may respond normally to thermal stimulus, but generally reacts feebly to heat and cold.

Electric pulp test shows marked variation from the normal.

Percussion and palpation tests are negative.

Radiographically:

R/E may not show anything of significance that is already not known clinically.

It may disclose inter proximal cavity not seen clinically or may suggest involvement of pulp horn.

Differential diagnosis:

Differentiate it from reversible pulpitis.

In reversible pulpitis pain disappears as soon as stimulus is removed.

Asymptomatic irreversible pulpitis may exhibit little or no pain except when food is packed into the cavity.

Pain produced is sharp, piercing and readily identified with the involved tooth.

Treatment:

Complete removal of pulp and placement of intracanal medicament.

In posterior teeth, pulpotomy can be done as emergency procedure.

Surgical removal is considered if tooth is not restorable.

Prognosis:

Prognosis is favourable if pulp is removed and tooth undergoes proper endodontic therapy and restoration.

Chronic Hyperplastic Pulpitis (Pulp Polyp)

Definition:

It is a productive pulpal inflammation due to an extensive carious exposure of a young pulp.

Rising out of carious shell of crown is a mushroom of living pilp tissue.

It is characterised by development of granulation tissue covered at times with epithelium and reulting from long standing low grade irritation.

Histopathology:

Surface is covered by stratified squamous epithelium.

The tissue in chamber is often transformed into granulation tissue, which projects from pulp to carious lesion.

Granulation tissue is young, vascular connective tissue containing PMN’s, lymphocytes and plasma cells.

Cause:

Slow progressive carious exposure of the pulp.

For pulp polyp development, a large open cavity a young resistant pulp and a chronic low  grade stimulus is necessary.

Symptoms:

Symptomless except during mastication when pressure of food bolus may cause some discomfort.

Diagnosis:

Generally seen in teeth of children and young adults.

Appearance of polypoid tissue is clinically characteristic: a fleshy reddish pulpal mass filling most of pulp chamber or even extending beyond the confines of the tooth.

Polypoid tissue is less sensitive tha pulp and more sensitive than gingival tissue.

Cutting of this tissue produces no pain.

Does not respond to thermal tests

Electric pulp tester – more current is required

Bleeds easily

Radiographically:

A large open cavity with direct access to pulp chamber.

Differential diagnosis:

To differentiate it from gingival tissue proliferation raise and trace the stalk of tissue back to its origin which is pulp chamber in case of Pulp Polyp.

Treatment:

Elimination of polypoid tissue followed by extirpation of the pulp then pulpectomy is done.

Prognosis:

For Pulp          - Unfavourable

For Tooth        - Favourable

Internal resorption

It is an idiopathic slow or fast progressive resorptive process occurring in the dentine of the pulp chamber or root canal of teeth.

Cause

It is not known but such patients often have a history of trauma.

Histopathology

It is the result of osteoclastic activity. The resorptive process is characterized by lacunae, which may be filled in by osteoid tissue. The osteoid tissue may be regarded as an attempt at repair. Multinucleated giant cells are present. The pulp is usually chronically inflamed.

Symptoms

It is usually asymptomatic. In the crown of tooth, internal resorption may be manifested as a reddish area called pink spot. This reddish area represents the granulation tissue showing through the resorbed area of crown.

Diagnosis

It may effect either the crown or root of the tooth, most readily recognized are the anterior teeth. It is diagnosed during routine radiographic examination. The appearance of the pink spot occurs late in the resorptive process, when the integrity of the crown has been compromised.the radiograph usually shows a change in the appearance of the wall in the root canal or chamber with a round or ovoid radiolucent area.

Differential diagnosis

It should be differentiated from external resorption. In internal resorption the rersorption defect  is more extensive in the pulpal wall on the root surface.

Treatment

Extirpation of the pulp stops resorptive process.

Pulp Degeneration

It is of following types :

Calcific degeneration

In this apart of pulp tissue is replaced by calcific material that is pulp stones or denticles are formed. This calcification occur either in the chamber or canal. The calcified material lies unattached within the body of the pulp. In another type the calcified material is attached to the wall of the pulp cavity and is an integral part of it. It is estimated that pulp stones are present in more than 60% of adult teeth. They are considered to be harmless concretions

Atrophic degeneration

In this type of degeneration observed histopathologically in pulps of older people, fewer stellate cells are present and intercellular fluid is increased. The pulp tissue is less sensitive.

Fibrous degeneration

It is characterized by replacement of the cellular elements by fibrous connective tissue.

A study by Bernick and Nedelman in 1997 demonstrated that in ageing pulp -:

- Progressive deposition of calcium masses

- Decrease in the nerves and blood vessels of pulp

- Presence of connective tissue sheaths giving a pulp a fibrotic appearance

Necrosis of pulp

Necrosis is death of pulp. It may be partial or total.

It is a sequel to inflammation, can also occur following a traumatic injury in which the pulp is destroyed before an inflammatory reaction takes place. As a result an ischemic infarction can develop and may cause a dry gangrenous necrotic pulp. It is of two types

1.Coagulation necrosis the soluble portion of tissue is precipitated. Caseation is a form of coagulation necrosis in which the tissue is converted into a cheesy mass consisting of coagulated protein                                                   

2.Liquefaction necrosis results when proteolytic enzymes convert the tissue into a softened mass, a liquid, or a amorphous debris

     

Cause

      Necrosis can be caused by any noxious insult injurious to the pulp, such as bacteria,   

       trauma and chemical irritation.

Symptoms

No painful symptom. Discoloration of the tooth is  the first indication that the pulp is dead. The dull or opaque appearance of the crown may be due merely to a lack of normal translucency.

     

Diagnosis

Radiographs show a large cavity or filling an open approach to the root canal and a thickening of the periodontal ligament. A tooth with a necrotic pulp does not respond to cold, the electric pulp test, or the test cavity. A few patient have a history of severe pain lasting from a few minutes to a few hours followed by sudden cessation of pain.

Histopathology

Necrotic pulp tissue, cellular debris and microorganisms may be seen in the pulp cavity.

Treatment

Consists of of preparation and obturation of root canals.

References:

1.      Endodontic practice, eleventh edition, Grossman pg 59-77.

2.      Textbook Of Endodontics, Anil Kohli pg 63-82.

3.      Endodontics, fifth Edition, Ingle & Bakland pg 95-174.