Calcium hydroxide cement : Calcium hydroxide cement SEMINAR PRESENTED BY: JHUG ISHT DEV
GUIDED BY: DR. BHAVIKA PANCHAL (MDS) Introduction : Introduction Calcium hydroxide is a relatively weak cement commonly employed as direct or indirect pulp capping agents.
Due to their alkaline nature they also serve as a protective barrier against irritants from certain restorations
Recently, a light cured calcium hydroxide base material and calcium hydroxide root canal sealing paste have been introduced. Applications : Applications For direct and indirect pulp capping
2. As low strength bases beneath silicate and composite restorations for pulp protections.
Apexification procedure in young permanent teeth where root formation is incomplete
4. Imminent or actual pulp exposure
-less than 0.5 mm remaining dentin estimated in older tooth or visualized as pink blush in younger tooth Indirect pulp capping : Indirect pulp capping Indirect pulp treatment is a procedure performed in a
tooth with a deep carious lesion approximating the pulp but without signs or symptoms of pulp
degeneration. It is performed in a tooth with a
diagnosis of reversible pulpitis and deep caries that
might otherwise need endodontic therapy if the decay
was completely removed.
Unintentional pulp exposure
Irreversible pulpitis Slide 6: Objectives:
restorative material should seal completely
vitality should be preserved
no post‐treatment signs or symptoms
no radiographic evidence of pathology
immature roots should show continued root development and apexogenesis Slide 8: Indications
reversible pulpitis when the deepest carious dentin is not removed to avoid a pulp exposure
pulp is judged by clinical and radiographically vital Available as : Available as Two paste system containing base and catalyst pastes in collapsible tubes.
Light cured system
Single paste in syringe form (pulpdent)
Powder form (mixed with distilled water) Commercial names : Commercial names Self cured :
Prisma VLC dycal Composition : Composition Base paste
Glycol salicylate 40%
Reacts with Ca(OH)2 and ZnO
Inert fillers, pigments
Calcium tungstate or barium sulphate
Provides radiopacity : Catalyst paste
Calcium hydroxide 50%
Principle reactive ingredients
Zinc oxide 10%
Zinc stearate 0.5%
Oily compound, acts as carrier Setting reaction : Setting reaction Calcium hydroxide reacts with the salicylate ester to form a chelate (amorphous calcium disalicylate)
Zinc oxide also takes part in the reaction. Setting time : Setting time 2.5 to 5.5 minutes
Factors affecting setting time
The reaction is greatly accelerated by moisture and accelerators.
It therefore sets fast in the cavity. Properties : Properties Calcium hydroxide cements have poor mechanical properties.
However, they are better than zinc oxide-eugenol. Mechanical properties : Mechanical properties Compressive strength:
10 -27 Mpa after 24 hrs
It has a low compressive strength.
The strength continues to increase with time.
It is low
Modulus of elasticity:
The low elastic modulus limits their use to areas not critical to the support of the restoration. Thermal properties : Thermal properties If used in sufficiently thick layers, they provide some thermal insulation.
However a thickness greater than 0.5mm is not recommended.
Thermal protection should be provided with a separate base. Solublity and disintegration : Solublity and disintegration The solubility in water is high.
0.4 to 7.8 %
Some solubility of the calcium hydroxide cement is necessary to achieve its therapeutic properties.
Solubility is higher when exposed to phosphoric acid and ether.
So care should be taken during acid etching and during application of varnish in the presence of this cement. Biological propertie : Biological propertie Effect on pulp:
The cement is alkaline in nature.
The high pH is due to the presence of free Ca(OH)2 in the set cement .
The pH ranges from 9.2 to 11.7
Formation of secondary dentin:
The high alkalinity and its consequent anti-bacterial and protein lysing effect helps in the formation of reparative dentin. Manipulation : Manipulation Equal lengths of the two pastes are dispensed on a paper and mixed to a uniform colour.
The material is carried and applied using a calcium hydroxide carrier or applicator (a ball ended instrument).
The material is applied to deep areas of the cavity or directly over mildly exposed pulp. Contraindications : Contraindications If there is active bleeding., the material is not applied. Slide 22: This calcium hydroxide liner should cover and protect any possible near or actual exposure and extend over a major portion of the excavated dentin surface.
Calcium hydroxide treatment of an exposed, healthy pulp promotes the formation of a dentin bridge which would close the exposure.
The peripheral 0.5 to 1mm of the dentin excavation should be left available for bonding the light-cured glass-ionomer cement base subsequently applied. Light activated calcium hydroxide cement : Light activated calcium hydroxide cement Light activated calcium hydroxide cement have recently become available.
Cal L.C is a light cure, fluoride releasing, radiopaque cavity liner and base material specially formulated for use with adhesives and composites and with conventional restorative materials.
It consists of calcium hydroxide and barium sulphate dispersed in a urethane dimethacrylate resin. It chemically bonds to adhesive primers, composites and other resin based materials, and it micromechanically bonds to dentin.
It also contains HEMA and polymerisation activators. Slide 24: It has a long working time and is less brittle than the conventional two paste system.
Cal L.C releases favorable Calcium ions, Hydroxyl ions, Fluoride ions and Phosphate ions. These are known to be beneficial to tooth structure, to stimulate secondary dentin formation and to have cariostatic properties.It sets very hard upon light curing, and it is virtually insoluble in water and oral fluids.
Indirect pulp capping Lining under all filling materials
Protection when applying the total etch technique. Calcium hydroxide root canal sealing pastes : Calcium hydroxide root canal sealing pastes Recently, a root canal sealer containing calcium hydroxide has been developed.
These are similar to the ones used for pulp capping but contain increased amount of retarders in order to extend the working time while they are being manipulated in the warm environment of the root canal. Advantages : Advantages Effective antibacterial properties without irritation.
They stimulate hard tissue repair in the apical foramen. Calcium hydroxide sealers : Calcium hydroxide sealers Slide 28: Recently several calcium hydroxide- based sealers have become commercially available as:
They are promoted as having therapeutic effects because of their calcium hydroxide content.
To be therapeutically effective, calcium hydroxide must be dissociated into Ca++ and OH-. Contraindications : Contraindications The calcium hydroxide content may dissolve, leaving obturation voids. This would ruin the function of the sealer, because it would disintegrate in the tissue.
It has poor cohesive strength. Role of calcium hydroxide in an endodontic treatment : Role of calcium hydroxide in an endodontic treatment Slide 31: Calcium hydroxide normally is used as a slurry of Calcium hydroxide in a water base.
Less than 0.2% of Calcium hydroxide is dissolved into Ca++ and OH- ions.
Water is used as a vehicle for the Calcium hydroxide paste.
In contact with air, Calcium hydroxide forms Calcium carbonate which is an extremely slow process of little clinical significance. Slide 32: These pastes should have the following characteristics:
composed mainly of calcium hydroxide which may be used in association with other substances to improve some of the physicochemical properties such as radiopacity, flow and consistency;
can be rendered soluble or resorbed within vital tissues either slowly or rapidly depending on the vehicle and other components;
may be prepared for use at the chairside or available as a proprietary paste;
within the root canal system they are used only as a temporary dressing and not as a definitive filling material Types of vehicles and their importance : Types of vehicles and their importance It has been asserted that all biological actions of calcium hydroxide will be progressed by the ionic disso-ciation in Ca ++ and OH- ions
The vehicle plays a most important role in the overall process because it determines the velocity of ionic dissociation causing the paste to be solubilized and resorbed at various rates by the periapical tissues and from within the root canal .
The ideal vehicle should:
allow a gradual and slow Ca++and OH- ionic release;
allow slow diffusion in the tissues with low solubility in tissue fluids;
have no adverse effect on the induction of hard tissue deposition Slide 34: Three types of vehicles are used:
Oily Slide 35: Calcium hydroxide is a slowly working antiseptic.
A 24hr contact period is required for complete killing of enterococci.
In clinical experimentation, 1 week of intra canal dressing has been shown to safely disinfect a root canal system,.
Sodium hypochlorite irrigation reduced the bacteria level by only 61.9%, but use of Calcium hydroxide in the canals for 1 week resulted in a 92.5% reduction. Slide 36: In addition to killing bacteria, calcium hydroxide has the extraordinary ability to hydrolyse the lipid moeity of bacterial lipopolysaccharide (LPS).
It inactivates the biologic activity of the LPS and thus reducing its effect.
This is a very desirable effect because dead cell wall material remains after the bacteria have been killed and can continue to stimulate inflammatory responses in the periradicular tissue. Slide 37: Calcium hydroxide may be mixed with sterile water or saline.
Also available commercially as:
DT temporary dressing
The mixture should be thick to carry as many calcium hydroxide particles as possible.
For maximal effectiveness, the root canal must be filled homogeneously to the working length.
Saturated calcium hydroxide solution mixed with a detergent is an effective antimicrobial agent suitable for irrigation. metapaste : metapaste Slide 39: Applications
Formation of a hard tissue barrier(Apexification)
Temporary root canal filling\
Internal & external root resorption
Exposed pulp in capping and pulpotomy Slide 40: Advantages
Easy cleaning and removing with good water solubility
Excellent antibacterial effect and radiopacity
Syringe type for easy delivery of the paste into the canal
Disposable tips for prevention of cross-contamination Slide 41: Cautions:
Do not fill beyond the apex.
Avoid direct exposure to sunlight.
Keep the syringe capped all the time.
Store in dry and cool area (10oC~24oC/50oF~77oF). - Improper storage can cause dryness or separation of the paste. Slide 42: Special Package
2 Syringes Metapex
2 Syringes Metapex & Metapaste Slide 43: Components
2.2g paste in a syringe (2 or 3 syringe packing available)
One ring rotator for direction control of the ti
Dimension : 228 × 61 × 22 (㎜)
Weight : 83g Clinical cases - Apexification : Clinical cases - Apexification Before treatment- Large apical foramen with anincomplete apex- Note the root resorption on the lateral surface of the apical third Slide 45: Metapaste filling Slide 46: Three months later- After removal of the paste, it shows a formation of theapical barrier Slide 47: Six months later- Excellent healing without further root resorption To locate real apical foramen : To locate real apical foramen - About 1-2 months after, X-ray shows exactly where the real apical foramen is.