IN ENDODONTICS IN CONSERVATIVE

1. CALCIUM HYDROXIDE
JAMES

2. Introduction
• Hermann’s (1920) introduced Calcium hydroxide formulation called Calxyl
induced dentinal bridging of the exposed pulpal surface. Since then the
emphasis has shifted from the “doomed organ” concept of an exposed
pulp
• In it pure form, this substance has a high pH and its dental use relates
chiefly to its ability to stimulate mineralization and also its antimicrobial
properties.
• Further advantages include easy preparation and a favorable influence on
the local environment, raising the acidic pH to alkalinity. So calcium
hydroxide is considered to be one of the biocompatible materials
indentistry

3. DEFINITION
• Calcium hydroxide is a strong alkali, which can be
formed by the reaction of calcium oxide. If the oxide is
treated with only sufficient water to make it crumble to
a fine, white, dry powder slaked lime is produced.
• Synonyms: calcium hydrate, caustic lime, hydrated
lime,lime, lime hydrate, slaked lime.

4. HISTORY
 Year 1838 - Nygren used ca(oH)2 for treatment of fistula dentalis
 Year 1851 - Codman used ca(OH)2 to preserve dental pulp
 Year 1920 -Hermann introduced calcium hydroxide for the treatment of infected root
canals.
 Year 1930 - Calcium hydroxide became frequently used in the vital pulp therapies.
 Year 1939 -Before the second World War an European immigrant Zander introduced
dentists in USA to its use.
 Year 1941 -The first literature regarding the successful healing using calcium Hydroxide
appeared.
 Year 1959 -The use of calcium hydroxide for apical closure was first reported by Granath.
 Year 1960 -Matsumiya and Kitumura clerly demonstrated, in a dog whose infected root
canals were packed with calcium hydroxide, showed a drastic reduction in the number of
microorganisms.

5. • Year 1964 – Kaiser proposed that CH is mixed with CMCP (camphorated
monochlorophenol)would induce formation of calcified barrier across the apex.
• Year 1966 - Frank popularized the use of calcium hydroxide for the apical closure.
• Year 1975 -Maisto classified the calcium hydroxide paste as an alkaline paste
because ofits high pH.
• Year 1976 -Cvek successfully used calcium hydroxide for induction of hard tissue in
the apical portions of the root canal, especially of immature teeth with infected
pulp necrosis.
• Year 1985 -Bystrom and Sundquist promoted calcium hydroxide as an antibacterial
agent and showed that 97% of the cases showed great success with calcium
hydroxide.
• Some commercially available calcium hydroxide products are Dycal, life,Hydrex,
care VLC, Dycal (light cured)

6. COMPOSITION
• Alkyl salicylate (iso-butyl salicylate or 1-methyl triethylene salicylate)
• Inert fillers – titanium oxide 12-14%
• Radiopacifer – barium sulphate 32-35%
• Calcium tungstate or calcium sulphate 14-15%
• Basic paste
• Calcium hydroxide 50-60%
• Zinc oxide 10%
• Zinc stearate 0.5%
• Ethylene toluene sulphonamides and paraffin oil 39.5%
Acidic paste

7. CLASSIFICATION
 Based on the setting time
i. Fast setting
ii. Controlled setting
iii. Slow setting
iv. No setting
 Based on mechanism of setting
Self curing – dycal
Light curing – prisma VLC dycal
 Based on vehicle used
Aqueous vehicle
Eg. Water, saline dental anesthetic, ringers solution, aqueous suspension of
methylcellulose.
 Viscous vehicle – ex. glycerine, polyethylene glycol and propylene glycol.
 Oily vehicles – Olive oil, oleic acid, linoleic and isosteric acid.

8. Mode of supply
• Can be supplied in powder form – powder can be mixed with distilled
water, saline solution to form a thick paste and applied as such.
• Can be supplied as two paste system, one base paste another catalyst
paste.
• Can be supplied as single paste (visible light).

9. CHEMICAL CHARACTERISTICS OF CALCIUM
HYDROXIDE
 Limestone(natural rock) composed of calcium carbonate (CaCO3)
 The combustion of limestone between 900ºC and 1200ºC causes
the following chemical reaction:
CaCO3 CaO + CO2
 The calcium oxide (CaO) formed is called ‘quicklime’ and has a
strong corrosive ability. When calcium oxide contacts with water,
the following reaction occurs:
CaO + H2O Ca(OH)2

10. Fava et al , IEJ 1999; 32: 257-282
 White odourless powder with a formula of Ca(OH)2.
 Molecular weight is 74.08
 Solubility in water is low (1.2g/l at 25ºC)
 High pH is 12.5-12.8
 Insoluble in alcohol
 It is chemically classified as a strong base
 In calcium hydroxide the ratio of hydroxyl ions and calcium ions is 45.89% and 54.11%.
 Powder has a slight bitter taste
 Powder has to be stored in air tight bottles due its reaction with atmospheric carbon dioxide.
Physical Characteristics:

11. MINERALISATION EFFECT
Ca(OH)2CALCIUM HYDROXYL
Neutralises the acid produced by
inflammatory osteoclasts
Optimum pH for pyrophosphatase
activity (10.3)
Increased levels of Ca2+ dependant
pyrophosphatase
Reduced capillary
permeability
Reduced serum flow
Reduced levels of inhibitory
pyrophosphate

12. CALCIFIC /DENTINE BRIDGE FORMATION
Application of Ca(OH)2 to a vital pulp. This repair material
appears to be the product of odontoblasts and C.T. cells.
A few minutes after the contact of pulp tissue with
calcium hydroxide, the formation of necrotic areas begins
At the limit of vital and necrotic tissue(rupture of
glycoprotiens in the intercellular substance) there is calcium
salts deposition.
The formation of mineralized tissue - 7th to the 10th day
The formation of dentinal matrix - initiates after the 15th day

13. APPLICATIONS OF CALCIUM HYDROXIDE IN
DENTISTRY
 Dentine
desensitizing agent
 Indirect pulp
capping
 Direct pulp capping
 Cavity Liners
 Bases
 Microleakage
 Intracanal medicament/
Root canal disinfection
 Hard tissue induction
root fracture/
resorption/perforation
 Apexification
 Apexogenesis
 Root canal sealer
 Avulsion
CONSERVATIVE ENDODONTICS

14. Physical properties
• Compressive Strength
7 minutes : 3.8 to 7.6 MPa to 550 psi.
30 minutes: 4.8 to 6.2 MPa to 750 – 900 psi
24 hours: 8.3 to 10.3 MPa or 1200 – 1500 psi
• Tensile strength : 10 MPa
• Modulus of elasticity: (low) - 0.37 Gpa
• pH : 9.2 to 11.7 (high alkaline)
• Setting time: 2.5 – 5.5 minutes.
• Solubility and disintegration: solubility is high 0.4 to 7.8%

15. HEALING WITH HIGH PH11-13
• ZONE OF OBLITERATION
• ZONE OF COAGULATIVE NECROSIS
• DENSE ZONE

16. ZONE OF OBLITERATION
• caustic effect ,contains area of superficial debris
• zone can be visualised after1hour of contact between caoh2 and
tissue
• it is induced by pressure of application and chemical injury due to
high conc of hydroxyl ions
• zone consists of debris dentinal fragments blood clot blood
pigments

17. ZONE OF COAGULATIVE NECROSIS
• STANLEYS MUMMIFIED ZONE
• ZONE CONSISTS OF DECALCIFIED PULP TISSUE
WITHOUT COMPLETE OBLITERATION OF
ARCHITECTURE

18. DENSE ZONE
• EARLY STAGE OF BRIDGE FORMATION, INCREASE
IN FORMATION AND ORGANISATION OF COLLAGEN
FIBRES.
• FINE AGROPHILLIC FIBRES /VON KORF S FIBRES
PREDOMINATE IN THIS REGION AND BECOME
ORGANISED IN PATTERN PERPENDICULAR TO LINE
OF DEMARCATION.
• SPORADIC TUBULAR FORMATION WITHIN
COLLAGENOUS MATRIX

19. • The main actions of calcium hydroxide come from the ionic
dissociation of ca & oH ions and the action of these ions on vital
tissue and bacteria generate the induction of hard tissue deposition
and the antibacterial effect (estrela 1994).
• Calcified barrier is formed by ca-oh2 when in contact with pulp
/periapical tissue determines the velocity of ionic dissociation
• Its biological properties are achieved by dissociation of ca2+ and
OH-ions
Fava,Saunder’s , IEJ 1999;32:257-282
MODE OF ACTION

20. • According to Maisto [1975], Goldberg [1982], the pastes
should have the following characteristics:
• It should be composed mainly of calcium hydroxide which
be used in association with other substances - to improve
some of the physicochemical properties such as
radiopacity, flow and consistency.
• Should be non-setting.

21. • Should be rendered soluble or resorb with in vital tissues either slowly
or rapidly
• depending on the vehicle and other components.
• Should be prepared for the use at the chair side or be available as a
proprietary paste.
• Should be used as only temporary dressing material and not as a
definitive filling material.
• Leonardo et al (1982) stated that a paste prepared with water or other
hydrosoluble non-viscous vehicle does not have good physiochemical
properties because it is not radioopaque is permeable to tissue fluids is
renderd soluble and resorbed from the periapical area and from within
the root canal. Fava,Saunder’s , IEJ 1999;32:257-282

22. CLINICAL IMPORTANCE
• Release calcium and hydroxyl ions more slowly for extended periods.
• Lower solubility of the paste when compared with aqueous vehicles probably because
of their higher molecular weights.
• pastes remain in direct contact with the vital tissues for extended time intervals
• appointments and redressings of the root canal is drastically reduced
USES
• Apexification
• Treatment of large periapical lesions
• Interappointment dressing in cases of vital pulpetomy
• Acute apical periodontitis
• Endodontic retreatment after endodontic & surgical failures

23. • Vital pulp therapy.
• Direct pulp capping.
• Indirect pulp capping.
• Pulpotomy
• Apexogenesis
• Routine intracanal dressing between appointments.
• Routine dressing.
• Long-term temporary dressing.
• Large periapical lesions – non surgical endodontic treatment
• Treatment of divergent apex in a pulpless tooth (Apexification).
• Control of persistent apical exudates into the canal.

24. • Prevention of root resorption.
• Idiopathic.
• Following the replacement of an avulsed tooth, or transplantation of a
tooth.
• Repair of iatrogenic perforations.
• Treatment of root fractures.
• Constituents of root canal sealers.

25. In operative dentistry
• AS A LINER
• They have a rapid initial set in the cavity under
the accelerating effect of moisture.
• They do not interfere with the setting reaction
of the Bis-GMA resins.
• It is generally considered that the initial set of
the material in thin sections is sufficiently hard
to resist the applied condensation pressures
that are required even for the lathe cut
amalgam alloys.

26. • According to sturdevants
• Liners are relatively thin layers of material used primarily to
provide a barrier
• to protect the dentin from residual reactants diffusing out of
a restoration.
• Liners are of two types
1. Thin film liners
2. Thick liners

27. Thin liners (1-50µm)
1. Solution liner or varnishes (2-5µm)
2. Suspension liners (20-25µm)
Thick liners- Also called cement liners (0.2-1mm).
• Used primarily for pulpal medications and thermal protection
bases (1-2mm) provide thermal protection and mechanical
support for the restoration by distributing local stresses from
the restoration across the underlying dentin surface

28. AS A BASE AND A SUB BASE
• Calcium hydroxide can be used both as a sub
base and as a base.
• It should be placed deep in deep portions of the
cavity preparation subsequently covered by a
definitive supporting base.
• It helps in repair of pulpal tissue
• It provides chemical insulation
• It replaces the lost portion of the dentin.
• Calcium hydroxide bases are of relatively of low
strength when compared to the other bases.
• These bases are used only for their therapeutic
benefits,chemical insulation or for retaining the
sub bases.

29. INDIRECT PULP TREATMENT
• Indirect pulp treatment is defined as “the application of a
medicament over a thin layer of remaining carious dentin,
after deep excavation, with no exposure of the pulp”
• Carious dentin actually consists of two layers having
different ultramicroscopic and chemical structures.
• The outer carious layer is irreversibly denatured, infected
and incapable of being remineralized and hence should
be removed.
• The inner carious layer is reversibly denatured but not
infected and is capable of being remineralized

30. • The technique: • carious dentin is removed with a sharp spoon excavator and a
hard set calcium hydroxide dressing is given to cover the remaining affected
dentin.
• The remainder of the cavity is then filled with a reinforced zinc oxide eugenol
cement or GIC. This sealed cavity is not disturbed for a minimum of 6-8 weeks
• At the next appointment radiographs of the affected tooth are taken to assess
the presence of reparative dentin.
• The temporary filling with calcium hydroxide is removed carefully.
• The reparative dentin layer is not disturbed. Over this another fresh application
of calcium hydroxide is given over which a permanent filling is done with a
suitable base.

31. CALCIUM HYDROXIDE AS AN INTRACANAL
MEDICAMENT
• plays a major role as an inter-visit dressing in the
disinfection of the root canal system.
• Calcium hydroxide is normally used as slurry of
Calcium hydroxide in a water base.
• At body temperature less than 0.2% of Calcium
hydroxide is dissolved into ca++ and OH- ions.
• Calcium hydroxide needs water to dissolve.
• Therefore it is most advantageous to use water as
a vehicle for the Calcium hydroxide paste

32. CALCIUM HYDROXIDE AS AN ENDODONTIC
SEALER
• Calcium hydroxide must be dissociated into Ca++ and OH-.
Therefore to be effective, an endodontic sealer based on calcium
hydroxide must dissolve and the solid consequently lose content.
• Thus one major concern is that the calcium hydroxide content
dissolve, leaving obturation voids. This would ruin the function of
the sealer, because it would disintegrate in the tissue.
• Recently introduced several calcium hydroxide sealers are
sealapex(kerr), apexkit(vivadent).

33. Advantages of Calcium hydroxide
1. Initially bactericidal then bacteriostatic.
2. Promotes healing and repair.
3. High pH stimulates fibroblasts.
4. Neutralizes low pH of acids.
5. Stops internal resorption.
6. Inexpensive and easy to use.

34. Disadvantages of Calcium hydroxide:
1. Does not exclusively stimulate dentinogenesis.
2. Does exclusively stimulate reparative dentin.
3. Associated with primary tooth resorption.
4. May dissolve after one year with cavosurface dissolution.
5. May degrade during acid etching.
6. Degrades upon tooth flexure.
7. Marginal failure with amalgam condensation.
8. Does not adhere to dentin or resin restoration

35. CALCIUM HYDROXIDE AS A PULP CAPPING AGENT
• Calcium hydroxide is generally accepted as the material of choice for pulp
capping.
• Histologically there is a complete dentinal bridging with healthy radicular pulp
under calcium hydroxide dressings.
• When calcium hydroxide is applied directly to pulp tissue there is necrosis of
adjacent pulp tissue and an inflammation of contiguous tissue.
• Dentinal bridge formation occurs at the junction of necrotic tissue and vital
inflamed tissue.
• Beneath the region of necrosis, cells of underlying pulp tissue differentiate into
odontoblasts and elaborate dentin matrix.

36. • Three main calcium hydroxide products are: Pulpadent, Dycal,
Hydrex(MPC).
• Pulpadent paste is considered to be most capable of stimulating early
bridge formation.
• Hydrex has been considered that fast capable of forming a bridge.
• Commercially available compounds of calcium hydroxide in a modified
form are known to be less alkanine and thus less caustic on the pulp.
• The action of calcium hydroxide to form a dentin bridge appears to be a
result of the low grade irritation in the underlying pulp tissue after
application.

37.  SINGLE PASTE SYSTEM
PULP DENT PASTE (Pulpdent Corp,
USA)
Goldberg 1982
Calicum hydroxide(52.5%)
Methyl cellulose(Suspension)
TEMPCANAL PASTE (Pulpdent Corp,
USA)
Similar to pulpdent with
addition of barium sulphate for
radiopacity and improved flow

38.  CALXYL(Otto &Corp., Germany)
-Herman 1920
Calcium hydroxide
NaCl,NaCO3, CaCl2, Mg2+
 CALAPSET(Scania Dental, Sweden)
-Ghose 1980
Calcium hydroxide(56%)
Calcium chloride (8mg)
Sodium bicarbonate( 4mg)
Sodium chloride(0.35mg)
Potassium chloride (8mg)
Water (suspension)

39.  METAPEX (META Dental
Corp.)
 Calcium hydroxide with
iodoform
 VITAPEX(NEO Dental,
Japan)
Calcium hydroxide 30%
Iodoform 40.4%

40.  FORENDO PASTE
(Pulpdent Corp., USA)
contains calcium hydroxide
, iodoform in a silicone oil
base.
 DIAPEX
(DiaDent,Canada)
Calcium Hydroxide and
Iodoform

41.  HYPOCAL(Ellinan Co., NY,
USA)
Calcium hydroxide (45%)
Barium sulphate (5%)
Hydroxymehtylcellulose (2%)
Water (4.8%)

42. BASE
Zinc Oxide
Calcium Phosphate
Calcium Tungstate
Iron Oxide
1, 3butyl glycoidisalicylate
CATALYST
Calcium Hydroxide
Zinc Oxide
Zinc Stearate
Iron Oxide
N-ethyl p-toluene
sulfonamide
DYCAL (Dentsply, USA)

43. Setting Reaction
 Calcium hydroxide reacts with salicylate ester to form a chelate
i.e., amorphous calcium disalicylate in the presence of toulene
sulphonamide that acts as the plasticizer.
 The chelates are held together by weak secondary attractions
rather than a strong polymeric structure.
 Setting time 2.5 to 5.5 min

44. CONSERVATIVE
 DENTINE DESENSITIZING AGENT
Ca(OH)2 has been advocated for the relief of hypersensitive
root dentine(Green et al 1977).
The proposed mechanism for reducing dentine permeability
include:
1. Physical blockage of the tubule orifices.
2. Production of precipitates or mineralization.
3. Stimulation of secondary dentine.
Milesovic , Journal of Dentistry 1991;19:3-13

45.  INDIRECT PULP CAPPING
 It is a technique of avoiding pulp exposure in the treatment of teeth
with deep carious lesions in which there exists no clinical evidence
of pulp degeneration or periapical pathology.
 Main purpose
 arrest the caries progress
towards the pulp
 promoting dentinal sclerosis
 remineralisation of carious
dentine
 preserving pulp vitality
Farhad,Mohammadi, IDJ 2005,55;293-301

46.  DIRECT PULP CAPPING
 Involves the application of a medicament , dressing or dental material to the exposed
pulp in an attempt to preserve its vitality.
 Calcium hydroxide has been the standard material of choice for several years.
Mechanism of action
CaOH2 applied directly to
pulp tissue
necrosis of adjacent pulp tissue
inflammatory response from the pulp
induction of odontoblastic bridge formation

47. Calcium hydroxide and/or calcium hydroxide sealers
can:
 Provide antibacterial action
 Stimulate periapical tissue healing
 Induce mineralization
 Induce apical closure via cemento genesis
 Inhibit root resorption subsequent to trauma
 Inhibit osteoclast activity via an high alkaline pH
 Seal or prevent leakage as good as or better than ZOE
sealers
 Less toxic than ZOE sealer.

48. CALCIUM HYDROXIDE IN APEXIFICATION
• In apexification technique canal is cleaned and disinfected, when tooth is free of
signs and symptoms of infection, the canal is dried and filled with stiff mix of calcium
hydroxide and CMCP. • Commercial paste of calcium hydroxide
(eg. Calasept, Pulpdent, Hypocal, Calyxl) may be used to fill the canals.
• Histologically the formation of osteodentin after placement of calcium hydroxide paste
immediately on conclusion of a vital pulpectomy has been reported.
There appears to be a differentiation of adjacent connective tissue cells; there is also
deposition of calcified tissue adjacent to the filling material.
• The calcified material is continuous with lateral root surfaces, the closure of apex
may be partial or complete but consistently has minute communications with the
periapical tissue.

49. CALCIUM HYDROXIDE IN PULPOTOMY
• It is the most recommended pulpotomy medicament for
pulpally involved vital young permanent tooth with
incomplete apices.
• It is acceptable because it promoted reparative dentin
bridge formation and thus radicular pulp vitality is
maintained to allow uninterrupted physiological
completion of root and root canals

50. • Histologically pulp tissue adjacent to calcium hydroxide was
first necrotized by the high pH of calcium hydroxide.
• This necrosis was accompanied by the acute inflammatory
changes in the underlying tissue.
• After 4 weeks a new odontoblastic layer and eventually a
bridge of dentin developed.
• Three histologic zones under calcium hydroxide in 4-9 days:
1. Coagulation necrosis. 2. Deep staining areas with varied
osteodentin. 3. Relatively normal pulp tissue, slightly
hyperemic, underlying an odontoblastic layer.

51. • Internal resorption may result from
overstimulation of the primary pulp by
the highly alkaline calcium hydroxide.
• This alkaline induced overstimulation
could cause metaplasia within the
pulp tissue, leading to formation of
odontoclasts.
• Also undetected microleakage could
allow large numbers of bacteria to
overwhelm the pulp and nullify the
beneficial effects of calcium hydroxide

52. CALCIUM HYDROXIDE IN WEEPING CANALS
• Sometimes a tooth undergoing root canal treatment shows
constant clear or reddish exudate associated with periapical
radiolucency.
• Tooth can be asymptomatic or tender on percussion. When
opened in next appointment, exudates stops but it again reappear
in next appointment, this is known as “weeping canal”.
• For such teeth dry the canals with sterile absorbent paper points
and place calcium hydroxide in canal.
• It happens because pH of periapical tissues is acidic in weeping
stage which gets converted into basic pH by calcium hydroxide.

53. • Calcium hydroxide can act even in the presence of blood
and other tissue exudates.
• It has a definite characteristics of producing ca ions,
resulting in less leakage at the capillary junction.
• It causes contraction of the pericapillary sphincters, thus
resulting in less plasma outflow. Hence, it is the material of
choice for weeping canals.

54. RECENT ADVANCES IN
CALCIUM HYDROXIDE

55. Features
Automix tips.
1:1 syringe ratio.
Accurate mixing with every application
Non-Eugenol, high pH
Non-irritating, lowers risk of post formulation
operative sensitivity.
Contains calcium hydroxide- Stimulates hard-
tissue formation.
Base/catalyst system
SEALAPEX EXPRESS (Sybron Endo)

56. APEXIT PLUS (Ivoclar Vivadent)
New formula, Apexit Plus is suitable for use in conjunction
with gutta-percha.
Free of pharmaceutical substances -corticoids, antibiotics and
formaldehyde-containing products.
Easy flowing composition
Slight setting expansion, low solubility, enables good and
durable seal.
Easy handling is supplied in practical automix syringes

57. APEXCAL (Ivoclar Vivadent)
 ApexCal is the new creamy calcium hydroxide paste for temporary
disinfectant dressings in the obturation of root canals.
ApexCal can also be used in indirect and direct pulp capping.
 Strong bactericidal effect.
 High radiopacity

58. Calcigel contains calcium hydroxide and carbonate of bismuth in
a mixture of water, glycerin, polyethylene glycol and other
additional agents.
Filling temporary disinfectant during endodontic therapy.
Indirect pulp capping of deep carious lesions
Direct pulp capping
CALCIGEL (Süd-Chemie AG,Germany)

59.  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.
 Contains hydroxyapatite in a urethane dimethacrylate resin.
CAL L.C. ( Prevest Denpro Ltd, Germany)

60.  Releases favourable Calcium ions, Hydroxyl ions, Fluoride ions and Phosphate
ions.
 Stimulates secondary dentine formation and has cariostatic properties.
 It sets very hard upon light curing
 it is virtually insoluble in water and oral fluids.
 Chemically bonds to adhesives and composites
 Time-saving direct application and light-curing
 Effective protection of the pulp
 Acid-resistant
 Ready-to-use one-component material

61. CONCLUSION
 Antibacterial property.Since the introduction of Calcium
Hydroxide in Dentistry by HERMAN , this medication has
been reported to promote healing in many clinical
situations.
 The biological and bacteriological action of Calcium
Hydroxide confers to its current success.

62. REFERENCES
• Text book pathway of pulp- cohen 10th edition
• Text book endodontics- ingle 6 th edition
• Text book philips dental material- anusavaice
• Text book materials used in dentistry. Mahalakshmi
• Mohammed mustafa. Role of CaoH on endodontics: a
review. GJMEMPH 2012.
• Siquerira. Mechanism of antimicrobial activity of
calcium hydroxide: a critical review. IEJ 1999.
• L.R.G. fava. Calcium hydroxide pastes: classification
and clinical indications. IEJ 1999.