Materials used to Materials used to preserve pulp vitalitypreserve pulp vitality

Calcium hydroxideCalcium hydroxide

The characteristics of calcium The characteristics of calcium hydroxide come from its dissociation hydroxide come from its dissociation into calcium and hydroxyl ions. into calcium and hydroxyl ions.

The action of these ions on tissues and The action of these ions on tissues and bacteria explains the biological and bacteria explains the biological and antimicrobial properties of this antimicrobial properties of this substance. substance.

it is possible to state that:it is possible to state that: 1. Dentin is considered the best pulpal 1. Dentin is considered the best pulpal protective, and protective, and calcium hydroxidecalcium hydroxide has proved, has proved, through numerous studies, its capability of through numerous studies, its capability of inducing the formation of a mineralized bridge inducing the formation of a mineralized bridge over pulpal tissue. over pulpal tissue.

2. It is necessary, whenever possible, to 2. It is necessary, whenever possible, to provide time for provide time for calcium hydroxide pastecalcium hydroxide paste to to manifest its potential of action on the manifest its potential of action on the microorganisms present in endodontic microorganisms present in endodontic infections. The maintenance of a high infections. The maintenance of a high concentration of hydroxyl ions can change concentration of hydroxyl ions can change bacteria enzymatic activity and promote its bacteria enzymatic activity and promote its inactivation.inactivation.

3. The site of action of hydroxyl ions of 3. The site of action of hydroxyl ions of calcium calcium hydroxidehydroxide includes the enzymes in the cytoplasmic includes the enzymes in the cytoplasmic membrane. This medication has a large radius of membrane. This medication has a large radius of action, and therefore is effective on a wide range of action, and therefore is effective on a wide range of microorganisms, regardless their metabolic microorganisms, regardless their metabolic capability. capability.

In microbial world, cytoplasmic membranes are In microbial world, cytoplasmic membranes are similar,independently on sort of microorganism similar,independently on sort of microorganism morphological and metabolical characteristics, morphological and metabolical characteristics, which means that this medication has a similar effect which means that this medication has a similar effect on aerobic, anaerobic, Gram-positive and Gram-on aerobic, anaerobic, Gram-positive and Gram-negative bacteria. negative bacteria.

4. 4. Calcium hydroxideCalcium hydroxide as temporary as temporary dressing used between appointments dressing used between appointments promotes better results on the periapical promotes better results on the periapical healing process than the treatment in healing process than the treatment in one appointment. one appointment. Calcium hydroxideCalcium hydroxide encourages the encourages the deposition of a hard tissue bridge that deposition of a hard tissue bridge that usually protects the dental pulp. usually protects the dental pulp.

calcium hydroxidecalcium hydroxide is an excellent therapeutic is an excellent therapeutic option when the clinical situation requires the option when the clinical situation requires the use of pulp capping agent and intracanal use of pulp capping agent and intracanal medication. medication.

Two effects of this medication need to be Two effects of this medication need to be consideredconsidered, , biologicalbiological and and antimicrobial effectsantimicrobial effects. . Thus, other factors can alter this effects, like the Thus, other factors can alter this effects, like the influence of vehicles in this properties and the influence of vehicles in this properties and the time of action for to express microbial control . time of action for to express microbial control . Other substances with objectives similar to Other substances with objectives similar to calcium hydroxide, like Mineral Trioxide calcium hydroxide, like Mineral Trioxide Agregate and Portland cement, have also been Agregate and Portland cement, have also been studiedstudied

In the dental pulp, calcium hydroxide has In the dental pulp, calcium hydroxide has been used as a pulp capping agent been used as a pulp capping agent because of its ability to stimulate because of its ability to stimulate mineralization; mineralization;

as intracanal dressing it has excellent as intracanal dressing it has excellent antimicrobial action, that favor to eliminate antimicrobial action, that favor to eliminate microorganisms after cleaning and microorganisms after cleaning and shaping, to neutralize the remaining shaping, to neutralize the remaining toxins, besides maintaining the temporary toxins, besides maintaining the temporary sealing. sealing.

The chemical dynamics of The chemical dynamics of calciumcalcium hydroxidehydroxide as demonstrated by ionic as demonstrated by ionic dissociation, characterizes its properties.dissociation, characterizes its properties.

The activation of tissue enzymes such as The activation of tissue enzymes such as alkaline phosphatase shows mineralizing alkaline phosphatase shows mineralizing effects and inhibiting effect on bacterial effects and inhibiting effect on bacterial enzymes, which leads to its antimicrobial enzymes, which leads to its antimicrobial property, illustrating the biological qualities property, illustrating the biological qualities of hydroxyl and calcium ions on both of hydroxyl and calcium ions on both tissue and microorganismstissue and microorganisms

BIOLOGICAL EFFECTBIOLOGICAL EFFECT

Calcium hydroxideCalcium hydroxide is a strong base is a strong base obtained through calcination (heating) of obtained through calcination (heating) of calcium carbonate until its transformation calcium carbonate until its transformation into calcium oxide. into calcium oxide. Calcium hydroxideCalcium hydroxide is obtained through the is obtained through the hydration of calcium oxide and the hydration of calcium oxide and the chemical reaction between calcium chemical reaction between calcium hydroxide and carbon dioxide forms hydroxide and carbon dioxide forms calcium carbonate. It is a white powder calcium carbonate. It is a white powder with a high pH (12.6) and is slightly soluble with a high pH (12.6) and is slightly soluble in water (solubility of 1.2 g/L, at a in water (solubility of 1.2 g/L, at a temperature of 25oC)36. temperature of 25oC)36.

The properties of calcium hydroxide come from The properties of calcium hydroxide come from its dissociation into calcium and hydroxyl ions its dissociation into calcium and hydroxyl ions and the action of these ions on tissues and and the action of these ions on tissues and bacteria explains biological and antimicrobial bacteria explains biological and antimicrobial properties of this substance.properties of this substance.

Changes in the biological properties can also be Changes in the biological properties can also be understood through the chemical reactions, understood through the chemical reactions, since calcium hydroxide, in the presence of since calcium hydroxide, in the presence of carbon dioxide, becomes calcium carbonate carbon dioxide, becomes calcium carbonate (weak acid oxide) and this product does not (weak acid oxide) and this product does not have calcium hydroxide's biological properties have calcium hydroxide's biological properties such as the mineralizing capability. such as the mineralizing capability.

MICROBIAL EFFECTMICROBIAL EFFECT

The mechanism of action of calcium hydroxide The mechanism of action of calcium hydroxide on microorganisms can be explained by the on microorganisms can be explained by the influence of pH on growth, metabolism and influence of pH on growth, metabolism and bacterial cell division. bacterial cell division. 

the hydroxyl ions from calcium hydroxide the hydroxyl ions from calcium hydroxide develop their mechanism of action in the develop their mechanism of action in the cytoplasmic membrane, because enzymatic cytoplasmic membrane, because enzymatic sites are located in the cytoplasmic membranesites are located in the cytoplasmic membrane

This membrane is responsible for essential This membrane is responsible for essential functions such as metabolism, cellular division functions such as metabolism, cellular division and growth and it takes part in the final stages of and growth and it takes part in the final stages of cellular wall formation, biosynthesis of lipids, cellular wall formation, biosynthesis of lipids, transport of electrons and oxidative transport of electrons and oxidative phosphorylation. phosphorylation. Extracellular enzymes act on nutrients, Extracellular enzymes act on nutrients, carbohydrates, proteins, and lipids that, through carbohydrates, proteins, and lipids that, through hydrolysis, favor digestion. Intracellular enzymes hydrolysis, favor digestion. Intracellular enzymes located in the cell favor respiratory activity of the located in the cell favor respiratory activity of the cellular wall structure. The pH gradient of the cellular wall structure. The pH gradient of the cytoplasmic membrane is altered by the high cytoplasmic membrane is altered by the high concentration of hydroxyl ions of calcium concentration of hydroxyl ions of calcium hydroxide acting on the proteins of the hydroxide acting on the proteins of the membrane (proteic denaturation). membrane (proteic denaturation).

The effect of the high pH of calcium The effect of the high pH of calcium hydroxide alters the integrity of the hydroxide alters the integrity of the cytoplasmic membrane by means of cytoplasmic membrane by means of chemical injury to organic components and chemical injury to organic components and transport of nutrients, or by means of the transport of nutrients, or by means of the destruction of phospholipids or destruction of phospholipids or unsaturated fatty acids of the cytoplasmic unsaturated fatty acids of the cytoplasmic membrane, observed in the peroxidation membrane, observed in the peroxidation process, which is a saponificationprocess, which is a saponification reactionreaction

Using mineral trioxide aggregate and calcium hydroxide as a pulp-capping

materials

Pulp capping is defined as the placement of a dental material over an exposed pulp to initiate the formation of irritation dentin at the site of injury. Classically, different formulations of calcium hydroxide (CH) have been used.

Today, a newer material is advocated for vital pulp therapy, mineral trioxide aggregate (MTA).

The exposed dental pulp has the capacity to heal when microleakage and bacterial contamination are prevented. Therefore,

it appears that an effective pulp-capping material should be biocompatible, that it should provide a biological seal and prevent bacterial leakage.

The pulps capped with MTA or calcium hydroxide showed dentin bridge formation or dentin chips present. Dentin chips may promote or retard healing. A dentin bridge has formed a complete barrier at the exposure site and the pulp is free of inflammations.

The reparative dentin did not originate from severely damaged odontoblasts; instead, undifferentiated cells that migrated from deep regions of the pulp replaced the degenerated odontoblasts. This explains why the reparative dentin is regular when is formed from areas where the odontoblasts remain intact.

Vital Pulp TherapyVital Pulp Therapy

The mechanisms involved in wound healing The mechanisms involved in wound healing of pulpal tissue (1) Inflammation (2) CaOH of pulpal tissue (1) Inflammation (2) CaOH effects (3) Reparative Dentinogenesis effects (3) Reparative Dentinogenesis

(4) Stem Cells (5) Growth Factors(4) Stem Cells (5) Growth Factors

Indirect Pulp CappingIndirect Pulp Capping

Indications for treatmentIndications for treatment: : Indirect pulp Indirect pulp capping is indicted on permanent teeth with capping is indicted on permanent teeth with immature apices if ALL the following immature apices if ALL the following conditions exist:conditions exist:

1.1. Tooth has a deep carious lesion that is Tooth has a deep carious lesion that is considered likely to result in pulp considered likely to result in pulp exposure during excavationexposure during excavation

2.2. No history of subjective pretreatment No history of subjective pretreatment symptomssymptoms

3.3. Pretreatment radiographs should exclude Pretreatment radiographs should exclude periradicular pathosisperiradicular pathosis

4.4. Patient has been fully informed that Patient has been fully informed that endodontic treatment may be indicated in endodontic treatment may be indicated in the futurethe future

Procedure:Procedure: Two treatment visits, 6 to 8 Two treatment visits, 6 to 8 months apart. 1st visit; caries biomass is months apart. 1st visit; caries biomass is excavated leaving affected dentin adjacent excavated leaving affected dentin adjacent to the pulp. CaOH or MTA is placed over to the pulp. CaOH or MTA is placed over the dentin followed by a base, and the the dentin followed by a base, and the tooth is soundly restored. 2nd visit: the tooth is soundly restored. 2nd visit: the restorative material and the residual caries restorative material and the residual caries mass is removed and the tooth restored.mass is removed and the tooth restored.

Direct Pulp CappingDirect Pulp Capping

Indications for treatmentIndications for treatment: : Direct pulp Direct pulp capping is indicated when all the following capping is indicated when all the following clinical conditions exist:clinical conditions exist:

1.1. Mechanical exposure of a clinically vital Mechanical exposure of a clinically vital and asymptomatic pulp occurs.and asymptomatic pulp occurs.

2.2. Bleeding is controlled at the exposure siteBleeding is controlled at the exposure site3.3. Exposure permits the capping material to Exposure permits the capping material to

make direct contact with the vital pulp make direct contact with the vital pulp tissuetissue

4.4. Exposure occurs when tooth is under Exposure occurs when tooth is under rubber dam isolationrubber dam isolation

5. 5. Adequate seal of the coronal restoration can be Adequate seal of the coronal restoration can be maintainedmaintained.. Patient has been fully Patient has been fully informed that endodontic treatment may be informed that endodontic treatment may be indicated in the futureindicated in the future

ProcedureProcedure: : A radiopaque capping material is A radiopaque capping material is place directly over the surface of vital pulp place directly over the surface of vital pulp tissue at the site of the pulp exposure followed tissue at the site of the pulp exposure followed by a base. The final restoration is placed over by a base. The final restoration is placed over the base. The status of the pulp and the base. The status of the pulp and periradicular tissues should be assessed periradicular tissues should be assessed through periodic recall exams.through periodic recall exams.