Calcium hydroxide in pediatric dentistry

Calcium hydroxide and its role in
pediatric dentistry
By Dr. Lilavanti Vaghela
MDS in Pediatric and Preventive Dentistry

Content
✓Introduction
✓History of calcium hydroxide
✓Characteristic of calcium hydroxide
Chemical Composition and Activity
Physical Properties
✓Classification of calcium hydroxide
✓Different vehicles
✓Mechanism of action of calcium hydroxide
✓Advantages -Diadvantages
✓Clinical applications of calcium hydroxide
•Calcium hydroxide as a cavity liner
•Calcium hydroxide when used in vital-Non vital pulp therapy
a. Indirect Pulp Capping
b. Direct Pulp Capping
c. Pulpotomy
d. pulpectomy
e. Apexification

✓Calcium hydroxide as a intracanal medicaments
✓As a constituent of a root canal sealer
✓Other applications of calcium hydroxide
a. Canals with exudates
b. Horizontal root fracture
c. Perforations
d. Root resorption
✓Coclusion
✓Referances

Introduction
•Theoverridinggoalofpediatricdentistryistodeterminewhatisbestforchildatthatmoment
andwhatisbestfortheadultintowhomthechildwilleventuallygrow.
•Thisgoalcanbeaccomplishedbypreventingdisease,relievingpain,improvingmastication
efficiency,enhancingspeech,andimprovingappearance.
•Becausemanyoftheseobjectivesrequirethereplacementoralterationoftoothstructure,the
mainchallengesforcenturieshavebeenthedevelopmentandselectionof biocompatible,
long-lasting,direct-fillingtoothrestorativesandindirectlyprocessedprostheticmaterialsthatcan
withstandtheadverseconditionsoftheoralenvironment.
Anusavice.Phillips’ScienceofDentalMaterials.11
th
Ed.Mosby.2006;1:1-3.

Anusavice, has broadly classified dental materials as
1)Preventive materials
2)Restorative materials
3)Auxiliary materials
1)Preventive dental materials
include pit and fissure sealants; sealing agents that prevent leakage; materials that are
used primarily for their antibacterial effects; and liners, bases, cements and restorative
materials that are used primarily because they release fluoride, chlorhexidine, or other
therapeutic agents used to prevent or inhibit the progression of dental caries.
Anusavice.Phillips’ScienceofDentalMaterials.11
th
Ed.Mosby.2006;1:1-3.

2) Restorative materials
consist of all synthetic components that can be used to repair or replace tooth
structure, including primers, bonding agents, liners, cement bases, amalgams,
resin based composites, compomers, hybrid ionomers, cast metals, metal-cera
mics, ceramics, and denture polymers.

3) Auxiliary dental materials
•are substances that are used in the process of fabricating dental prostheses and
appliances but that do not become a part of these devices.
•These includes acid-etching solutions, impression materials, casting investments, gypsum
cast and model materials, dental waxes, acrylic resins for impression and bleaching trays,
acrylic resins for mouth guards and occlusion aids, and finishing and polishing abrasives.

•Calcium Hydroxide is one of the wonderful materials that basically falls into preventive as
well as restorative material categories, as it has been used in variety of purposes since its
introduction to dentistry in the early part of the twentieth century.
•Its dental use relates chiefly to its antibacterial properties and the ability to induce repair
and to stimulate hard-tissue formation.
•Dental application of calcium hydroxide include as a Dentin desensitizing agent, Pulp cap
technique-indirect as well as direct; As a liner & base; in Apexogenesisand Apexification;
in a Root Canal Sealer; and as a endodontic intracanal medicament. Moreover Hard
tissue induction in root fractures, root perforation & root resorption.

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 hydrate
✓slaked lime

History
•CalciumHydroxidehasbeenusedforlongtimefordentalpurposes.
•Despiteofthenumerousattemptstoreplaceitbyothersubstances,calciumhas
extraordinaryroleindentistry,bothinpureformandincombinationwithother
substances.
•Duringthelast200yearstherehavebeenmanychangesintherationalegoverningthe
treatmentoftheexposeddentalpulpasitwaslongagoobservedthatanexposed
pulphealedwithgreatdifficulty,ifatall.
•Theearliestaccountofpulptherapywaswaybackin1756,whenPhillipPfaffpackeda
pieceofgoldoveranexposedvitalpulptopromotehealing.
StanleyHR.Pulpcapping:conservingthedentalpulp–canitbedone?Isitworth?OralSurgOralMedOralPathol
1989;68:628-639.

•UntilHermann’sintroductionofamaterialsoeminent,whichmarkedanewerain
pulptherapy,whenhedemonstratedthataCalciumHydroxideformulacalled
Calxyl®induceddentinalbridgingoftheexposedpulpalsurface.
•Sincethentheemphasishasshiftedfromthe“doomedorgan”conceptofan
exposedpulptooneofhopeandrecovery.
StanleyHR.Pulpcapping:conservingthedentalpulp–canitbedone?Isitworth?OralSurgOralMedOralPathol
1989;68:628-639.

Lime
•General term for calcium containing oxides or hydroxides.
•The rocks and minerals from which this material derived is called Calcium carbonate.
•Burning (calcinations) converts them into highly caustic Quicklime, CaO(Calcium Oxide).
•Subsequent addition of water, convert it into Slaked lime or hydrated lime, Ca(OH)
2
(Calcium Hydroxide). The process is called Slaking lime.
•Slaked lime is useful to prevent bleeding, to cicatrizing, to heal wound and cuts,
and also to soothe burned skin.
DuffinCJ,MoodyRTJ,GardnerC.Thorp;Ahistoryofgeologyandmedicine;4:72.

•CalciumHydroxide,anoldremedy,alsorecommendedforthetreatmentof
“Fistuladentalis”in1838byNygren.
•ButCalciumHydroxidegainedwideacceptanceafterlandmarkstudybyBernhard
W.Hermann,1920ashefirsttimeusedCalciumHydroxidetofillrootcanals.
•Heclearlydemonstratedtheantibacterialeffectofcalciumhydroxideininfected
rootcanalswithoutanyadversereactions.
•TheaimofHermannwasnottofindanewagentfordirectpulpcappingor
pulpotomybutamethodfor“biologicalrootcanaltreatments”.Thematerial
HermannusedwasCalxyl®,manufacturedbyOtto&Co.,Frankfurt,Germany.
HermannB.KalziumhydroxidAlsMittelZumBehandelnUndFüllenVonZahnwurzelkanälen.Wurzburg,Disserta
tion1920.

•ToprovebiocompatibilityofCalciumHydroxide,Hermannperformedthefirst
successfulvitalpulpotomyaround1930,andcouldshowthatitiswellsuitableto
keepthepulptissuevitalwithout impairingitsfunctionandtoinducehardtissue
formation.
•In1938,TeuscherandZanderprovidedexperimentalresultsontheuseofapasteof
Calciumhydroxidetocoveramputedpulps.
•Theactualreportedtechniqueofpulpotomyusingcalciumhydroxidewasdescribed
byZanderandLawin1942,andhistologicalevidenceofrepairwithformationofa
newlayerofodontoblastsandasecondaryirregulardentinbarrierhasbeengivenby
ZanderandGlassin1949.
ZanderHA,LawDB.Pulpmanagementinfracturesofyoungpermanentteeth.JAmDentAssoc1942;29:737-741.

•Munch in 1931 made the suggestion to mix “lime” with vitamins for pulp
capping.
•The agent was offered on the market as Pulpatekt®, and was a compound
made of different calcium salts, vitamins and chlorophenol camphor for
disinfection.
•The add-on of chlorphenolcamphor proved to be adverse, so it was later
omitted.
•Instead, sterilized bone marrow of calves embryo was added
.

•Flohrin1936alsointroducedapreparationcalledVitapulp®.
•HewasafraidthatHermann’scalciumhydroxidecouldinducetissuenecrosis
duetothealkalinepHvalue.
•Byaddingcalciumsalts,FlohrloweredthepHvalueofcalciumhydroxide
andmixeditwithdentinchips.
•ToavoiddirectcontactandpressuretothepulptissueFlohradditionally
coveredtheexposurewithasmallpieceofblottingpaperbeforeVitapulp
wasapplied.

•A disadvantage of calcium hydroxide is the fact that it is an aqueous non-hard-setting
paste.
•Hence, Champion in 1941 was convinced that calcium hydroxide was not suitable as a
definitive root canal filling material as suggested by Hermann.
•Therefore, Champion developed a hard-setting calcium hydroxide preparation called
Endoxyl® in 1941.
•Endoxyl® was composed of two pastes containing calcium hydroxide, calcium gluconate
and calcium glycerinphosphate, which could be used for root canal fillings as well as
direct pulp capping.

•In 1953 Castagnolacompared the results of direct pulp capping with materials mainly from
the 1930s and 1940s and calcium hydroxide using histological evaluations and comparing
previous data from the literature.
•In all comparisons, calcium hydroxide clearly had the best results.
•Even Ingle has stated that historically, most effective capping material is calcium hydroxide.

•Eastlickrecommendedcalciumhydroxideforusewithexposedpulpsinteethwithimmature
apicesin1943.
•Theuseofcalciumhydroxideforapexificationwaspopularizedintheearly1960sbyDr.Alfred
L.FrankinhispresentationattheAAEmeetingin1964,andhisdetailedapplicationsthat
becameknownasthe"FrankTechnique"werepublishedin1966.
•Heithersayhasprovidedaratherextensivetreatiseonthewiderangeofapplicationsfor
calciumhydroxide.

•Use of sterile water as a vehicle with calcium hydroxide powder for root canal dressing
was described by Matsumiya& Kitamura in 1960.
•Crabb in 1965 was the first to use distilled water with calcium hydroxide powder
treatment of large periapical lesions.
•An old suggestion proposed by Yacometti1952 was to add penicillin to a calcium hydro
xide-distilled water paste to be used as a pulp capping material.

•Steineretal.in1968firstusecalciumhydroxidewithglycerineasitishygroscopic
innature,glycerineisveryusefulasmoisteningsubstancefurthermoreitisnontoxic
andisusedasanintracanallubricant.
•Siqueira&Uzedain1996addedcamphoratedparachlorophenoltoacalciumhydro
xide+glycerinepasteinordertoextenditsantibacterialspectrumagainstsome
speciesofobligateandfacultativeanaerobicbacteria.

•Berckin1950usecalciumhydroxidemethylcellulosepastefordirectpulpcapping
lateronwhichiscommerciallyavailableasPulpdent®.
•Maisto&Capurroin1964introducedapastecomposedofequalvolumesof
calciumhydroxidepowderandiodoformmixedwitha5%aqueoussolutionof
methylcellulose.
•Laurichessein1980addedtwodropsofcamphoratedparachlorophenolinthea
bovepreparationandGiroetal.in1993proposedtheuseofcarboxymethylcellul
oseinsteadofmethylcellulose.

•Leonardoetal.in1976introducedapastecontainingcalciumhydroxidewith
polyethyleneglycolwhichcontainbariumsulphateforradiopacity.
•LaterLeonardo&Lealin1991replacedthebariumsulphatebyzincoxideandit
iscommerciallyavailableasCalen®
•Furthermore,0.15mLofcamphoratedparachlorophenolwasaddedtothepaste
whenusedincasesofinfectedrootcanals;thispasteisnowaproprietarybrand–
Calen+camphoratedparachlorophenol®
•Yoshibaetal.in1994proposedanewformulation,addingatricalciumphosphate
tothecalciumhydroxidepowderandsalineforcappingamputedpulps.

•Sazaketal.in1996havesuggestedaddingLedermix(LederleLab.,Muènchen,Germany)
toacalciumhydroxide-salinepastetobeusedafterpulpotomywiththepurposeof
reducingpostoperativepainandinflammation.
•Thecalciumhydroxidecontainingapulpcappingagent,Dycal®(Dentsply-Caulk,
Milford,DE),alsobecamepopularsince1970stotilldate.

DycalI DycalII DycalIII
Dycal® I had a relatively high water
solubility and a relatively low
compressive strength.
•In order to increase the compress
ive strength and decrease the
solubility of Dycal® I, the manufa
cturer added more polymer to
the material.
•lower the water solubility from 6.
7 to 1-2% per 24 h and increased
the compressive strength from
2400 to 3700-4700 psi.
•However, the compressive strengt
h of Dycal® II was still low
enough that it might fail during
amalgam condensation or during
function.
•manufacturer to reformulate Dyca
l® by adding a urethane dimetha
crylateresincapable of being
light-cured with visible light.
•This led to a large increase in
compressive strength (from 3700-
4700 for Dycal® II to 12,000-15,0
00 psi for Dycal® III) and a
concomitant decrease in water
solubility, from 1-2% per 24 h to
<0.5%.
StanleyHR,PameijerGH.Pulpcappingwithanewvisible-light-curingcalciumhydroxidecomposition(PrismaV
LCDycal).OperDent1985;10:156-163.

•Vitapex®(Neo Dental Chemical Products Co. Ltd, Tokyo, Japan). This paste was introduced
by Kawakami et al.in 1979. It is composed of calcium hydroxide, iodoform, silicone oil and
other substances.
•Metapex® (Meta Biomed Co Ltd, Korea), calcium hydroxide with iodoform is
used now a days widely as a root canal filling material, as sealer, weeping canals.
Its success rate is more than 90%.
•KalaskarR and DamleSG in 2004 evaluated the potential of lyophilized freezed
dried platelet with calcium hydroxide as pulpotomy agent and found out that it
had 100 percent success.

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).

Characteristic of calcium hydroxide
Chemical Composition and Activity
•Limestone is a natural rock mainly composed of calcium carbonate (CaCO
3) which forms
when the calcium carbonate solution existing in mountain and sea water becomes
crystallized.
•The combustion of limestone between 900
o
Cand 1200
o
Ccauses the following chemical
reaction:
•The calcium oxide (CaO) formed is called `quicklime' and has a strong corrosive ability.
•When calcium oxide contacts water, the following reaction occurs:
•
CaCO
3→CaO+ CO
2
CaO + H
2O →Ca(OH)
2
FarhadA,MohammadiZ.Calciumhydroxide:areview.IntDentJ2005;55:293–301.

•It is a white odourless powder with the chemical formula Ca(OH)
2
•molecular weight →74.08
•It has low solubility in water →(around 1.2 g/L at 25
o
C), which decreases with a rise in
temperature
•It has been demonstrated that the dissociation coefficient of Ca(OH)
2→0.17, which
controls the slow release of both calcium and hydroxyl ions. This low solubility is a
useful clinical characteristic as an extended period is necessary before it becomes
solubilised when in direct contact with fluids from vital tissues.

•ThepurepowderhasahighpH→(approximately12.5–12.8)andisinsolubleinalcohol.
•Thematerialischemicallyclassifiedasastrongbase,itsmainactionscomefromthe
ionicdissociationofCa
2+
andOH
-
ionsandtheireffectonvitaltissues,generatingthe
inductionofhard-tissuedepositionandbeingantibacterial.
•AccordingtoRehmanetal.,Ca(OH)
2dissociatesintocalciumandhydroxylionson
contactwithaqueousfluids.

Solubility
•The solubility of calcium hydroxide bases has been measured in several solvents for
various periods of immersion.
•For various commercial products, values ranged
From 0.4% to 7.8% in →distilled water at 37
o
C for 24 hours,
from 0.1% to 6.2% in→35% phosphoric acid for 60 seconds,
from 0.3% to 1% in→ether for 10 seconds.
•Some solubility of the calcium hydroxide is necessary to achieve its therapeutic
properties, although an optimum value is not known.
CraigeRG,PowersJM;CraigeRestorativeDentalMaterial;11
th
Ed20:625-626.

Thermal properties
•Calcium hydroxide bases may provide some thermal insulation to the pulp if
used in sufficiently thick layers. Practically, thermal protection should be
provided by the overlying high-strength base
.
Material thickness
•Dycalmanufacturing company has described that material thickness should
be approximately 0.8 mm-1 mm
DycalManufacturingCompanyPaper,Dentsply,Chaulk.

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/m2
• pH: high alkaline: 9.2 to 11.7
• Setting time: 2.5 –5.5 minutes.

Compressive Strength
(MPa)
Tensile Strength (MPa) Elastic Modulus (GPa)
Calcium hydroxide (self
cured)
12-26 1 0.4
Calcium hydroxide (light
cured)
96 38 -

Properties of Various Dycal®
Dycal® I Dycal® II Dycal® III
Water solubility (% in 24 h) 6.76% 1-2% <0.5%
Acid solubility (% in 37% H
2PO
4in
60 s)
2.65% 2.0 –2.5 % <0.18
Compressive strength (psi) 2400 3700-4700
12,500-15,000
pH (24 h) 11.4 9-10 9-10

Composition
Acidic paste
• Alkyl salicylate (iso-butyl salicylate or 1-methyl triethylenesalicylate)
• 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%

•Alkyl salicylate is dysfunctional chelating agent.
•On mixing this with paste containing zinc oxide and calcium hydroxide, amorphous
calcium disalicylateis formed.
•The sulphonamidecompound used in the paste is present merely as a carrier.
•Some cements contain paraffin oils instead of sulphonamides.
•These elements are more hydrophobic and release their calcium hydroxide more slowly.
•Some commercially available calcium hydroxide products are Dycal, life, Hydrex,
care VLC, Dycal(light cured)

Light Cured paste formulation
•Dimethacrylateeg.Bis GMA
• Hydroxy ethyl methacrylate (HEMA)
• Calcium hydroxide
• Polymerizing activator
• Barium sulphate
✓The purpose of HEMA is to produce a relatively hydrophilic polymer, which can absorb
water and release, calcium hydroxide to create an alkaline environment.

CompositionofSelfCureDycalandLightCureDycal®
Dycal® Visible Light Cure Dycal®
Base paste Catalyst paste Calcium hydroxide
Calcium tungstate Calcium hydroxide Calcium hydroxyapatite
Zinc oxide Zinc oxide Barium sulphate
Disalicylateester of 1,3
butylene glycol
Titanium dioxide Fluorides
Resin matrix (UDMA)

Classification
Calcium hydroxide can be classified as certain ways,
(1)Basedonsettingmechanism
(2)Basedontypeofvehicleused
(3)Basedonmaterialadded

(1)Basedonsettingmechanism→setting
→nonsetting
(2)Basedontypeofvehicleused
Aqueousvehicle(Eg.Water,salinedentalanesthetic,ringerssolution,aqueoussus
pensionofmethylcellulose).
Viscousvehicle–(ex.glycerine,polyethyleneglycolandpropyleneglycol)
Oilyvehicles–(eg.Oliveoil,oleicacid,linoleicandisostericacid)
(3)Basedonmaterialadded
eg.Monomer,varnish,oil,acidetc.
ForemanPC,BarnesIE.Areviewofcalciumhydroxide.IntEndodJ1990;23:283-297

Setting materials
•ThetherapeuticpropertiesofthesettingcalciumhydroxidematerialsarerelatedtotheirpH.
•Itisalsodependentonthelevelsofunboundcalciumandhydroxylionsthatremainafter
thematerialhasset,anditfollowsthattheegressofionsfromthesetmaterialwillleadtoa
reductionofitsmass.
•Onefactorwhichincreasestheavailabilityofthehydroxylionisthehydrophobicnatureofthe
material.
•Themorehydrophobic,thelesslikelyisdiffusiontooccur,
Eg,Hydrex®,wasmorehydrophobicthanDycal®duetothepresenceofaparaffin
solventwhichpreventedthediffusionofwaterintothesetmaterial.
Based on setting mechanism

•Anadditionalfactortobeconsideredinthedissolutionofcalciumhydroxideis
theeffectofbacteria,associatedwithmicroleakage,onthesetmaterial.
•Watts&Patersonestablishedthatbacteriamaybepresentincontactwith
calciumhydroxide.ThiscouldlowerthepHofthematerialbyconvertingitto
calciumcarbonate,andmightexplainwhyearlyDycal®preparationsseemedto
disappearfrombeneathpermanentrestorations.
WattsA,PatersonRC.Pulp-cappingstudieswithanalarcalciumhydroxideandzincoxide-eugenol.IntEndodJ1987;20:169-176.

There are two basic setting mechanisms
(i)The two-paste system: It is based on the reaction between calcium and zinc ions
and a salicytatechelating agent, and is accelerated by the presence of water.
(ii)The single-paste system:It utilizes the polymerization of a dimethacrylateby
means of light, and is represented by Prisma VLC Dycal®.
•A potential disadvantage of the dimethacrylatesystems, when used as a base beneath
composite restorations, is their adherence to the composite material and subsequent
withdrawal from the base of the cavity during polymerization.

Non-setting materials
•calcium hydroxide may be applied either dry, or using distilled water as the vehicle.
•Clinically, this has the disadvantage that the mixture forms a slurry which may separate
and can be difficult to manipulate within the root canal by puddling; alternatively, it may
be mixed into a very thick paste which can be placed into the root canal with an
amalgam carrier and condensed with root canal pluggers.
•Proprietary brands overcome this problem by using methyl cellulose as a vehicle, with
varying amounts of water. This results in homogeneous pastes of varying consistency,
with good handling properties.
•Other admixtures have been suggested, such as local anaesthetic solution, camphorated
monochlorphenol(CMCP), beechwood creosote, Ledermixand radiopacifiers.

ForemanPC,BarnesIE.Areviewofcalciumhydroxide.IntEndodJ1990;23:283-297
Non Setting Calcium Hydroxide Materials
Material Vehicle
Analar calcium hydroxide Water
Pulpdent® Methyl cellulose
Hypo-Cal® Methyl cellulose
Reogan® Methyl cellulose

BASED ON TYPE OF VEHICLE
•When calcium hydroxide powder is mixed with a suitable vehicle, a paste is formed and,
because the main component is calcium hydroxide, Maistoclassified these formulations
as alkaline pastes because of their high pH.
These pastes should have the following characteristics:
1.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;
2. Non-setting;
3. Can be rendered soluble or resorbed within vital tissues either slowly or rapidly depending
on the vehicle and other components.
4. May be prepared for use at the chairside or available as a proprietary paste;
5. Within the root canal system they are used only as a temporary dressing and not as a
definitive filling material.
LeonardoMR,LealJM,SimoesFilhoAP.Endodontiatratamentodoscanaisradiculares.SaoPaulo:Panamericana1982.

•Theeasiestmethodtoprepareacalciumhydroxidepasteistomixcalciumhydroxide
powderwithwateruntilthedesiredconsistencyisachieved.
•However,Leonardoetal.statedthatapastepreparedwithwaterorotherhydrosoluble
non-viscousvehicledoesnothavegoodphysicochemicalproperties,becauseitisnot
radio-opaque,ispermeabletotissuefluidsandisrenderedsolubleandresorbedfrom
theperiapicalareaandfromwithintherootcanal.
•Fortheseandthefollowingreasons,Leonardoetal.recommendedtheadditionof
othersubstancestothepaste:
1. To maintain the paste consistency of the material which does not harden or set;
2. To improve flow;
3. To maintain the high pH of calcium hydroxide;
4. To improve radiopacity;
5. To make clinical use easier;
6. Not to alter the excellent biological properties of calcium hydroxide itself.

•calciumhydroxidepasteforuseinpedodonticsiscomposedofthepowder,
avehicleandaradiopacifier.
•Othersubstancesmaybeaddedtoimprovephysicochemicalpropertiesor
theantibacterialaction.

Typesofvehiclesandtheirimportance
•ActionsofcalciumhydroxidewillbeprogressedbytheionicdissociationinCa
2+
andOH
-
ions
.
•Thevehicleplaysamostimportantroleintheoverallprocessbecauseitdeterminesthevelocity
ofionicdissociationcausingthepastetobesolubilizedandresorbedatvariousratesbythe
periapicaltissuesandfromwithintherootcanal.
AccordingtoFava,theidealvehicleshould:
1.AllowagradualandslowCa
2+
.andOH
-
ionicrelease;
2.Allowslowdiffusioninthetissueswithlowsolubilityintissuefluids;
3.Havenoadverseeffectontheinductionofhardtissuedeposition.
FavaLRG.Calciumhydroxidepaste.considerationsaboutyourjobinendodonticsclinic.RevistaPaulistaOdontol1991;13:36-43.

✓When calcium hydroxide is mixed with one of these substances, Ca
2+
and OH
-
are rapidly released.
✓This type of vehicle promotes a high degree of solubility when the paste remains in direct contact
with the tissue and tissue fluids, causing it to be rapidly solubilized and resorbed by macrophages.
✓The root canal may become empty in a short period, delaying the healing process.
•Water
•saline,
•dental anaesthetics with or without a vasoconstrictor,
•Ringer's solution,
•aqueous suspension of methylcellulose or carboxymethylcellulose
•anionic detergent solution.
Aqueous vehicle

Water
•Theeasiestmethodtoprepareacalciumhydroxidepasteistomixthepowderwithwater.
•However,theliteraturedescribesdifferenttypesofwaterwithwhichtopreparethepaste,
includingsterilewater,distilledwater,steriledistilledwater,bidistilledwaterandsterile
bidistilledwater.
•Usuallythispasteispreparedonasterileglassslabwithasterilespatula.
•Thepowderismixedwiththeliquiduntilthedesiredconsistencyisachieved.
•Thepasteiscarriedintotherootcanal.

•chemical characteristics of such a paste were evaluated by different authors,
eg, pH(Conradoet al. 1965, Leonardo et al. 1992),
ionic dissociation (Leonardo et al. 1992)
diffusion through dentine (Leonardo et al. 1993a, Esberardet al. 1996).
•The antibacterial effect was studied by Martins et al. (1979), Bremer (1980) and Di Fiore et al. (1983),
whilst the solvent action was evaluated by Hasselgrenet al. (1988).

Sterile water
•First evaluated in apexificationprocedures in dog teeth (Vojinovic& Srnie1975) and as
a dressingin infected root canals (Matsumiya& Kitamura 1960).
In humans indication of this paste:
•direct pulp capping (Sommer et al. 1975, Horstedet al. 1985),
•pulpotomy and apexogenesis(Corpron& Dowson 1970, Goldman 1974)
•apexification procedures (Erdogan 1997),
•an apical plug before gutta-percha filling in non-vital teeth with an open apex
(Michanowicz& Michanowicz1967)
•internal resorption with perforation of the dentinal wall (Barclay 1993).
Fava LRG, Saunders WP. Calcium hydroxide pastes: classification and clinical indications (Review). Inte
rnational Endodontic Journal, 32, 257±282, 1999.

Distilled water
•First used by Crabb (1965) →treatment of large periapical lesions
Pastes containing this vehicle were chemically evaluated for:
•pH →(Conradoet al. 1965,Leonardo et al. 1992, Fuss et al. 1996), ionic dissociation (Leonar
do et al. 1992, Marques et al. 1994, Simon et al. 1995, Felippe1998),
•tissue solvent action →(Morgan et al. 1991, Yang et al. 1995)
•antibacterial effect →(Siqueira & Uzeda1997)

It was evaluated for its effect,
•on dentine (Holland et al. 1978a),
•direct pulp capping material (Ogawa et al. 1974, Holland et al. 1980a, 1982),
•temporary dressing material after vital pulp extirpation (Sekineet al. 1963a, Holland et al. 1978)
•apexification procedures (Binnie & Rowe 1973)
•chronic periapical lesions in dogs (Holland et al. l979b)
•iodoform or bismuth carbonate should be added to improve thradiopacityof the paste (Holland
et al. 1981, Rezende 1982).
•An old suggestion proposed by Yacometti(1952) was to add penicillin to a calcium hydroxide-
distilled water paste to be used as a pulp capping material.

Sterile distilled water
•First evaluated in human direct pulp capping (Patterson & Van Huysen1954),
•in apexification procedures (Wechsler et al. 1978).

Bidistilledwater
•According to Laurichesse(1980) →Albouwho first used bidistilledwater as the vehicle
of the paste in normal clinical cases.
Sterile bidistilledwater
•This vehicle was recommended by Breillatet al. (1983) for human apexogenesis
and apexification procedures.

Saline or sterile saline
•According to the United States Pharmacopeia (1989) saline is prepared by dissolving 9 g of sodium
chloride in water to make 1000 mL.
Following charachteristicwas evaluated:
✓pH (Anthony et al. 1982, Estrela et al. 1995b, Penicheet al. 1996),
✓ionic dissociation (Foster et al. 1993, Marques et al. 1994, Estrela et al. 1995b, Sim
on et al. 1995, Gomes et al. 1996),
✓tissue solvent action (Wakabayashi et al. 1995),
✓antibacterial effect (Safaviet al. 1985, Stuart et al. 1991, Barbosa et al. 1995, Estrel
a et al. 1995a, Siqueira & Uzeda1996, Sydney 1996),
✓apical microleakage (Porkaewet al. 1990, Siqueira & Fraga 1995) and some
✓methods to remove the paste from within the root canal (Guigneset al. 1991).
Fava LRG, Saunders WP. Calcium hydroxide pastes: classification and clinical indications (Review). Inte
rnational Endodontic Journal, 32, 257±282, 1999.

Clinically, it was evaluated in,
•non-vital immature teeth (Cvek1972, Cvek& Sundstrom 1974, Gallagher & Mourino1979)
•perforations (Bogaerts 1997)
•internal resorption at the site of an intra-alveolar root fracture (Cvek1974)
•external inflammatory root resorption (Rabie et al. 1988),
•luxated non-vital teeth (Cvek1992)
•antibacterial dressing in infected teeth (Barbosa et al. 1995)
•infected teeth with associated acute or chronic periodontitis (Orstaviket al. 1991)
•non-vital infected teeth with associated cutaneous sinus tract (Foster et al. 1992)
•endodontic retreatment after endodontic and surgical failures (West & Lieb1985) and as a dressing
after partial pulpectomy (Engstrom & Spangberg1967).

Anaesthetic solutions
•Anaestheticsolutions, with or without a vasoconstrictor, have been used as the vehicle of the
paste because these solutions are readily available, sterile and easy to handle.
•These solutions have an acid pH, but when mixed with the calcium hydroxide powder, the final
paste has a high pH which is maintained over time.
According to (Stamos et al. 1988, Marques et al. 1994, Prokopowitsch1994, Estrela et al. 1995b,
Fusset al. 1996, Peniche et al. 1996 → they promote a rapid ionic release
Fava LRG, Saunders WP. Calcium hydroxide pastes: classification and clinical indications (Review). Inte
rnational Endodontic Journal, 32, 257±282, 1999.

This paste has been indicated for,
•human apexification procedures by Goldman (1974), Taintor(1977),
•pulp capping material by Armstrong & Hoffman (1962).

Ringer's solution
•According to the United States Pharmacopeia (1989), this solution has sodium chloride (8.6 g),
potassium chloride (0.3 g), calcium chloride (0.33 g) and water to 1000 mL.
•First described by Granath(1959) in e in cases of traumatic injuries.
•Chemically, this paste was evaluated for alterations in the pH of dental structures when used as
a temporary dressing (Tronstadet al. 1981).

Clinically, it has been evaluated in,
•indirect pulp capping (Nyborg1955),
•in apexification procedures (Cvek1972)
•as a temporary dressing both after vital pulpectomy (Nyborg& Tullin1965,
Stromberg 1969)
•in non-vital teeth (Cvek1976)
•treatment of post-traumatic sequelae such as luxation and replantantion
(Cvek1973, 1989).
Fava LRG, Saunders WP. Calcium hydroxide pastes: classification and clinical indications (Review). Inte
rnational Endodontic Journal, 32, 257±282, 1999.

Distilled water Crabb,1965
Bidistilledwater Albou,1980
Sterile bidistilledwater Breillatet al,1983
saline United state of pharmacopeia,1984
Ringer lactate United state of pharmacopeia,1984

Methylcellulose and Carboxymethylcellulose:
•Historically,methylcellulosewasthevehicleofapastewidelyusedinSouthAmerica,mainlyin
Argentina.
•Maisto&Capurrointroducedapastecomposedofequalvolumesofcalciumhydroxidepowder
andiodoformmixedwitha5%aqueoussolutionofmethylcellulose.
•ItsantibacterialeffectwasevaluatedbyDiFioreetal,anditwasrecommendedinApexification
procedureandinindirectpulpcapping.
Laurichesseproposedthefollowingmodificationoftheoriginalformula:
•calciumhydroxideandiodoforminaratio2/3:1/3,twodropsofcamphoratedparachlorophenol
anda3% aqueoussolutionofmethylcelluloseasthevehicle.

•Giro et al. (1993) proposed the use of carboxymethylcellulose or, according to the United
States Pharmacopeia (1989), polycarboxymethyletherof cellulose, as the vehicle in the
following formula:
0.5 g of calcium hydroxide to 0.5 mL of a 1.66% solution of carboxymethylcellulose
•In another suggested formulation, 0.25 g of zinc oxide was added for radiopacity.

Anionicdetergentsolution
•Itiswellknownthatdetergentsdecreasethesurfacetensionbetweentwosurfaces
andfacilitatesubstancepenetration.
•Thisisperhapsthereasonwhycalciumhydroxidepowderhasbeenmixedwithan
aqueousdetergentsolutiontoincreasetheactionofthecalciumhydroxidedeeper
intothetissues.
Studies
•Barbosaetal.(1994)testedtheantibacterialeffectofapastecomposedofcalcium
hydroxideandsodiumlauryldiethyleneglycolethersulphate.
•Penicheetal.(1996)evaluatedthepHofapastecontainingcalciumhydroxideands
odiumlaurylsulphate.

Proprietary Brands:
•Calxyl® (Otto & Co., Frankfurt, Germany).
•Pulpdent®and Tempcanal®(PulpdentCorp., Brookline, MA, USA)
•TempCanal®
•Calvital® (Neo Dental Chemical Products Co., Tokyo, Japan)
•Reogan®(Vivadent, Schaan, Liechtenstein)
•Calasept®(Scania Dental AB, Knvista, Sweden):
•Hypocal®(EllinanCo., Hewlatt, NY, USA)
•Calcicur®(VOCO, Auxhaven, Germany)
•DT Temporary dressing®(Dental Therapeutics AB, Nacka, Sweden)
•Calcipulpe®
•Hidropulpe® (Lab. Zizine, France).
•Serocalcium(Casa Wild, Basel, Switzerland).
•Hydroxine®(Lab. AtoZizine, France).
•Acrical®(Bames-Hind Laboratories, USA).
•Calnex®(Associated Dental Products Ltd, London, UK).
Fava LRG, Saunders WP. Calcium hydroxide pastes: classification and clinical indications (Review). Inte
rnational Endodontic Journal, 32, 257±282, 1999.

Calxyl® (Otto & Co., Frankfurt, Germany)
•oldest manufactured→ and was introduced by Hermann (1920)
Uses
•As pulpotomy in vital pulp therapy
•As apical barrier formation in apexification
•Calxyl®Paste Syringe (pH> 12.6) is a Calcium hydroxide paste in a dosing syringe, unsurpassed for endodo
ntic treatment and temporary root filling.
•Calxyl®suspension is used for disinfection of the root canal
This paste is a solution of calcium hydroxide + water with the addition of th
e following blood salts: sodium carbonate, sodium chloride, calcium chlorid
e, potassium chloride and traces of magnesium.
Fava LRG, Saunders WP. Calcium hydroxide pastes: classification and clinical indications (Review). Inte
rnational Endodontic Journal, 32, 257±282, 1999.

Pulpdent® and Te
mpcanal®
of calcium hydroxide (52.5%) in an aqueou
s suspension of methylcellulose
DPC , pulpotomy,
apexification, perforations,
large periapical lesions and
external resorption.
Calvital® Powder+ liquid.
powder: calcium hydroxide (78.5%),
iodoform (20%), guanoflacin(0.1%) and
sulphatiazol(1.4%), liquid: T-cain (0.5%),
propyleneglycol(50%) and distilled water
(49.5%).
DPC, pulpotomy in deciduous
teeth, pulpotomy in permanen
t teeth, intracanal dressing afte
r vital pulpectomy and as a fin
al filling coupled with gutta-pe
rcha points
Reogan® calcium hydroxide, barium sulphate, casein
and magnesium hydroxide.
Apexification, dressing in vital
or non-vital teeth with or with
out periapical lesions radiogra
phically
Calasept® calcium hydroxide (56%), calcium chloride
(8 mg), sodium chloride (0.35 mg), sodium
bicarbonate (4 mg), potassium chloride (8
mg) and water sufficient for 100 g of the
paste.
IPC, DPC, apexification, in retre
atment cases and in luxated n
on-vital teeth
43
Hypocal® calcium hydroxide (45%), barium sulphate (
5%), hydroxymethylcellulose(2%) and wate
r (48%). However, Ida et al.
148
presented th
e following formula: calcium hydroxide (45
%), barium sulphate (5%), glycolcellulose(2
%) and distilled water (48%).
apexification
It Offers 3-Way Protection
Biological Protection:Desensitizes the
dentin by stimulating the formation of
sclerotic and reparative dentin and by
increasing the density of the dentin as
much as 25% in 15 days.
Chemical Protection:pH > 12. Neut
ralizes acids and other irritants foun
d in dental etching gels, adhesives a
nd restoratives.
Physical Protection:Fills the dentin
al tubules with calcium hydroxide.
Does not interfere with the seating
of crowns and inlays.

DT Temporary dressing® unoxygenated calcium hydroxide + sterilized distilled water
Calcipulpe® calcium hydroxide + carboxymethylcellulose
Hidropulpe® calcium hydroxide and barium sulphate in a solution of met
hyl benzoate
Calcigel® calcium hydroxide, methylcellulose and water
Acrical® 9-aminoacridine hydrochloride (0.2%), benzalkonium
chloride (0.1%), calcium hydroxide (28%) and barium
sulphate (5%). Benzalkonium chloride is a cationic detergent
and thus a watersolublevehicle.
Calnex® sterilized calcium hydroxide plus blood serum salts and met
hylcellulose
Fava LRG, Saunders WP. Calcium hydroxide pastes: classification and clinical indications (Review). Inte
rnational Endodontic Journal, 32, 257±282, 1999.

•AccordingtoSilvathehighmolecularweightofthesevehiclesminimizesthedispersion
ofcalciumhydroxideintothetissueandmaintainsthepasteinthedesiredareafor
longerintervals.
•Thisfactorprolongstheactionofthepaste,andCa
2+
andOH
-
ionswillbegivenoffat
lowervelocity.
•Itisthroughthismechanismthatthesepastesremainindirectcontactwithvitaltissue
forextendedtimeintervals.
•Asaviscousvehiclecontainingpastemayremainwithintherootcanalfora2-4month
interval,thenumberofappointmentsandre-dressingsoftherootcanalisdrastically
reduced.
eg,
•glycerine,
•polyethyleneglycol
•propyleneglycol.
Viscousvehicles

Glycerine
•Glycerine is a viscous, colourless transparent liquid with a characteristic odour, sweetish in
taste and hygroscopic.
•It can be mixed with water, acetone, alcohol and other glycols in any proportion but is
insoluble in chloroform, ether, benzene and volatile oils.
•Its molecular weight is 92.02

•Becauseofitshygroscopicproperties,glycerineisveryusefulasamoisteningsubstance
and,asitissolubleinwater,itiseasilyremoved.
•Furthermore,itisnon-toxicandisusedasanintracanallubricant.
•Thefirstuseofacalciumhydroxidepastewithglycerineinitsformulawasreportedby
Steineretal.inapastecomposedofcalciumhydroxide,camphoratedparachlorophenol,
bariumsulphateandglycerine.
•Thispastewasemployedforroot-endclosureofimmaturenon-vitalteeth.
•Thepasteisobtainedbymixingcalciumhydroxidewithsyntheticglycerineandhas
beenevaluated foritsantibacterialeffect.Aradiopacifiermaybeaddedtoimprove
radiopacity,suchasiodoformorbariumsulphateina1:8ratiowiththecalcium
hydroxidepowder.
Fava LRG, Saunders WP. Calcium hydroxide pastes: classification and clinical indications (Review). Inte
rnational Endodontic Journal, 32, 257±282, 1999.

This paste has been used in cases of
•chronic abcesseswith extraoral fistulae (Salamat & Rezai1986 CË aliskanet al. 1994)
•acute abcessesor chronic periapical lesions (CË aliskan& Sen 1996)
•internal resorption with or without root perforation (CË aliskan& Turkun1997)
•repair a fractured root (CË aliskan& Pehlivan1996)
•internal resorption (CË aliskan& Turkun1996)

Polyethyleneglycol
•Polyethyleneglycolis a viscous, colourless liquid with a characteristic odour and it is
slightly hygroscopic.
•It is miscible in any proportion with water, acetone, alcohol and other glycols but is
insoluble in ether and benzene
•Its pH ranges between 4.5 and 7.5.
•A paste composed of calcium hydroxide (70%), iodoform (30%) and polyethyleneglycol
as the vehicle was employed by Bellacosaet al. in a clinical case of external/internal
resorption.

•Maeda(1960)→introducedapastecontainingcalciumhydroxide,polyethyleneglycol
1500asabaseandsulphisomidineandeugenolasantibacterialagents.
•Kurimoto(1961)→testedthesamepasteasanintracanaldressing,withandwithoutthe
antibacterialagents,inhumaninfectedpulplessteethwithassociatedperiapicallesionsan
dfoundahighfrequencyoffavourablecases.
•Leonardoetal.→introducedapastecontainingcalciumhydroxide(2g),polyethylenegly
col400(1.75ml),bariumsulphate(1g)forradiopacityandhydrogenizedcolophony(0.05
g)toimprovephysicalproperties.
•LaterLeonardo&Lealreplacedthebariumsulphatebyzincoxideinthesameproportion.
LeonardoMR,LealJM.Endodontictreatmentrootcanals,2ndEdn.SäoPaulo:Panamericana1991.

Propyleneglycol.
•Propyleneglycolis a clear, colourless, odourless liquid with a slightly characteristic taste
resembling that of glycerine.
•Chemically, it is a dihydric alcohol with a syrup consistency, hygroscopic in nature
and non-toxic that can be mixed with water, acetone and alcohol in any proportion.
•It is widely employed as a useful vehicle for pharmaceutical preparations such as
antihistaminies, barbiturates, paracetamol and those used for parenteral administration
•Moreover, this substance is a suitable vehicle for members of the vitamin B group,
pyrazolines, aspirin and chloral hydrate
Fava LRG, Saunders WP. Calcium hydroxide pastes: classification and clinical indications (Review). Inte
rnational Endodontic Journal, 32, 257±282, 1999.

•Bhat & Walkevardemonstrated a strong antibacterial action of propyleneglycolagainst
common microorganisms found in infected root canals and suggested its wider
application in endodontics as a gentle vehicle for intracanal medicaments.
•Its hygroscopic nature permits the absorption of water, which ensures a good sustained
release of calcium hydroxide for long periods.
•Another advantage of this substance is its consistency, which improves the handling
qualities of the paste.
BhatKS,WalkevarS.Evaluationofbactericidalpropertyofpropyleneglycolforitspossibleuseinendodontics.JHealthSci(Arogya)1975;1:54-59.
The first report using a calcium hydroxide paste containing this vehicle
was by Saiijo(1957), who added antibacterial agents and asbestos powder

These pastes have been evaluated in humans,
•as an intracanal dressing after vital pulpectomy (Saiijo1957, Machida 1960, Sekine
et al. 1963a)
•for the non-surgical treatment of large periapical lesions (Hussey & Kennedy 1990).

Calen® (S.S. White + ArtigosD
entários, Rio de Janeiro, RJ, Bra
zil)
calcium hydroxide (2.5 g), zinc o
xide (0.5 g), hydrogenized colop
hony (0.05 g) and polyethylenegl
ycol400 (1.75 ml).
✓Apexification ,
✓in the treatment of large peri
apical lesions originating fro
m infected root canals,
✓as an interappointment dressi
ng in cases of vital pulpecto
my,
✓in acute apical periodontitis
✓in endodontic retreatment aft
er endodontic
✓surgical failures
Calen + camphorated parachlor
ophenol® (S.S. White + Artigo
sDentários, Rio de Janeiro, RJ,
Brasil).
Leonardo et al. added camphora
ted parachlorophenol(CMCP, 0.1
5 ml) to the original Calen formu
lation
non-vital and infected teeth with
associated periapical lesions.
Fava LRG, Saunders WP. Calcium hydroxide pastes: classification and clinical indications (Review). Inte
rnational Endodontic Journal, 32, 257±282, 1999.
ProprietaryBrands

•Oily vehicles are non-water-soluble substances that promote the lowest solubility
and diffusion of the paste within the tissues.
•Pastes containing this kind of vehicle may remain within the root canal for longer
than the pastes containing aqueous or viscous vehicles.
LopesHP.Theuseofcalciumhydroxideassociatedwithoilyvehicleinendodontictreatmentofteethwithnecrosedpulpandopenapex(
Thesis).RioDeJaneiro1987.
Eg,
olive oil,
silicone oil,
camphor (the essential oil of camphorated parachlorophenol),
metacresylacetate
some fatty acids such as oleic, linoleic and isostearicacids
Oilyvehicles

Olive oil
•Purified olive oil is a primrose or slightly green coloured liquid with a characteristic
odour, which is non-soluble in water but fairly soluble in alcohol.
•Chemically it is composed of esters of fatty acids such as oleic, linoleic, palmitoleic,
estearicand linolenic acids. It must be kept in an amber coloured flask.
•It promotes low solubility for the calcium hydroxide but improves its physical properties
•Because of the low solubility, the paste has a low diffusion within the tissues.

Camphorated parachlorophenol
•Camphorated parachlorophenol, or camphorated paramonochlorophenol(CMCP), was
introduced by Walkhoffin 1891
.
.
•It comprises 33-37% parachlorophenoland 63-67% camphor.
•Parachlorophenol(C
2H
5OCl, molecular weight 128.56 has a characteristic phenolic
odour and is presented in crystal form.
•Camphor (C
10H
16O, molecular weight 152.54) is acetone obtained from Cinnamomum
camphoraor synthetically in the laboratory; it has a characteristic and penetrating
odour, a bitter taste and low solubility in water
.
.
Fava LRG, Saunders WP. Calcium hydroxide pastes: classification and clinical indications (Review). Inte
rnational Endodontic Journal, 32, 257±282, 1999.

•The pronounced disinfectant action of parachlorophenoldepends on the liberation of
the chlorine in the presence of phenol.
•When camphorated parachlorophenolis the vehicle of a calcium hydroxide paste, it is
an oily vehicle because camphor is considered an essential oil with low solubility in
water.
•A paste containing the above constituents was introduced by Frank and Kaiser and
became very popular in the United States after the publication of an article describing
the guidelines for apexification procedures in human immature non-vital teeth.
KaiserHJ.Managementofthewideopenapexwithcalciumhydroxidecompounds.Twenty-FirstAnnualMeetingOfTheAmericanAssociationOfEn
dodontics.USA:WashingtonDC1964.

Metacresylacetate.
•According to Weiss, this substance was first introduced to dentistry by Coolidge in 1912
for the treatment of necrotic pulps.
•Chemically, metacresylacetateis the acetic ester of metacresolin combination with
benzene.
•It is an oily liquid with antibacterial, analgesic and sedative properties.
•When calcium hydroxide is mixed with metacresylacetate, a chemical reaction occurs
yielding calcium cresilateand acetic acid.
•The acetic acid suffers an ionic dissociation and gives off H
+
ions, which decreases the pH

Eugenol
•Molecular weight 164.20
•Obtained from oil of cloves and other sources (United States Pharmacopeia 1989).
•A paste containing calcium hydroxide and eugenol was evaluated for pulpotomy in deciduous
dog teeth (Russo & Holland 1974).
•In humans it has been employed as an intracanal dressing for vital and non-vital deciduous
teeth (Murata 1959).
Fava LRG, Saunders WP. Calcium hydroxide pastes: classification and clinical indications (Review). Inte
rnational Endodontic Journal, 32, 257±282, 1999.

ProprietaryBrands
L & C® (HerpoProdutosDentAriosLtda., Rio d
e Janeiro, RJ, Brazil).
✓introduced by Lopes & Costa Filho
✓powder : calcium hydroxide (2 g), bismuth
carbonate (1 g) and hydrogenized colophony
(0.05 g),
✓liquid: olive oil (0.16 ml).
use→ Apexification, resorptions and perforations
Vitapex® (Neo Dental Chemical Products Co. L
td, Tokyo, Japan).
✓introduced by Kawakami et al
✓calcium hydroxide (30.3%), iodoform (40.4%),
silicone oil (22.4%) and other substances
(6.9%).
Use –as root canal filling material in primary
teeth
Fava LRG, Saunders WP. Calcium hydroxide pastes: classification and clinical indications (Review). Inte
rnational Endodontic Journal, 32, 257±282, 1999.

CalciumHydroxideandOtherSubstances
RadiographicContrastMedia
•Calcium hydroxide mixed with any of the quoted vehicles lacks radiopacity and is not easily
seen radiographically.
•This is the main reason radiopaque materials are added to the paste, thereby allowing
identification of lateral and accessory canals, resorptive defects, fractures and other structures.
•A radiopacifiershould have an atomic weight higher than calcium for radiopacity purposes.
•Eg, barium sulphate and bismuth, and other compounds containing iodine and bromine.
•As bismuth salts have some degree of toxicity and soluble barium salts are extremely toxic
materials and relatively insoluble, the actual alternative is to use a more soluble radiopaque
substance.

•Tavanoetal.1978,statedthattherearethreetypesofiodinecompounds:
solubleiodineorganicsubstances,
nonsolubleiodineoils
slowlyabsorbableiodineoils.
•Whenmixedwithcalciumhydroxidepowder,thesesubstanceswillbecomethe
vehicleofthepasteaswellasbeingtheradiopaqueagent.

Corticosteroid-AntibioticSolutions
•Theuseofcorticosteroidstoreduceinflammationandmaintainthevitalityandintegrity
oftheinjuredpulptissueisanestablishedprocedure.
•Ascalciumhydroxidehasbeenprovedtoofferbetterclinicalresults,someattemptshave
beenmadetomixthesetwosubstancesandevaluatetheseformulationsforendodontic
purposesinvitalpulptherapy,suchasindirectpulpcappingandpulpotomyprocedures.
Fiore-DonnoG.BaumeLJ.Effectsofcappingcompoundscontainingcorticosteroidsonthehumandentalpulp.
HelvetiaOdontologicacta1962;6:23-32.

•A very popular formulation is a paste composed of a mixture of calcium hydroxide and
Ledermix(LederleLab.).
•This anti-inflammatory + antibiotic compound has triamcinolone acetonide and
demethylchlorotetracyclinecalcium and clinically evaluated in direct pulp capping,
pulpotomy, routine intracanal dressing and apexification procedures and in the treatment of
large periapical lesions.

Antibiotics
•Quillinetal.suggestedaddingmetronidazoleandchlorhexidinetoacalcium
hydroxidepasteandtestedthisformulationforitsantibacterialeffect.
•AnotherassociationwasproposedbyAntoniazzi&Marques,whichinvolvedmix
ingcalciumhydroxide(0.13g),metronidazole(0.6g),ciprofloxacin(0.6g)and
polyethyleneglycol1000.

Calcium Hydroxide's Association With Different Vehicles: In Vitro Action on
Some Dentinal Components
(María Gabriela Pacios,2003)
[chlorhexidine digluconate, propylene glycol (PG), anestheticsolution, camphora
ted monochlorophenol(CMCP), and CMCP-PG. The control solution contained
Ca(OH)(2) without vehicle.]
conclusion -test solutions with the root dentin remained alkaline. A release of
proteins, hydroxyproline, and phosphorus was observed.
Influence of Different Vehicles on the pH of Calcium Hydroxide Pastes
(María Gabriela Pacios,2004)
distilled water, chlorhexidine, propylene glycol, anestheticsolution, camphorated
p-monochlorophenoland camphorated p-monochlorophenol-propylene glycol.
Conclusion -The type of vehicle was shown to influence the final pH of the pas
tes.
Efﬁcacy of calcium hydroxide paste prepared
with different vehicles against salivary
microbial inﬁltration of root canals.
(Marili D, 2013)
saline solution (Group 1), polyethylene glycol (Group 2),
or polyethylene glycol and camphorated paramonochlorophenol(Group 3).
Conclusion -Calcium hydroxide paste prepared with saline solution was most
effective for retarding microbial contamination
Effect of calcium hydroxide pastes and vehicles on root canal dentin microh
ardness
(María G Pacios,2014)
The vehicles are: Distilled water, chlorhexidine, carticainein the anestheticsoluti
on, propylene glycol, monochlorophenoland monochlorophenol-propylene gl
ycol.
Conclusion -All vehicles and pastes, except distilled water, significantly decrease
d the microhardness of the root dentin; however, calcium hydroxide + camphor
ated monochlorophenol-propylene glycol and camphorated monochlorophen
ol-propylene glycol showed the highest decrease

Evaluation of calcium ion release and change in pH on combinin
g calcium hydroxide with different vehicles
(C Grover, 2014)
-distilled water, propylene glycol, gutta-percha points and chitosan
Conclusion -Chitosan can be used as a promising vehicle for calcium
hydroxide to maintain an alkaline pH and to allow sustained release
of calcium ions in the root canal system.

Antimicrobial properties of calcium hydroxide dressing when used for long-term application: A systematic review
(Garima Sharma,2018)

BASED ON MATERIAL ADDED
•Calcium hydroxide compounds are often classified as → homogeneous group of materials,
generally in terms of a list of trade names; however, because of the differing chemical
composition of such compounds, it seems advisable to differentiate various subgroups.

Based on Material Added to Calcium Hydroxide
Subgroup Hardening reaction
Trade name/ example
1
Aqueous suspension (water
+ calcium hydroxide)
Generally lacking (formation of salts
at the surface)
Pulpdent ® paste
2
Liner
(varnish + calcium hydroxid
e)
Evaporation of the solvent Hydroxyline®
3
Paste
(oil + calcium hydroxide)
Saponification
Gangraena®
Merz ®
4
Cement
(acid + calcium hydroxide)
Formation of salts/chelates Dycal ®
5
Filled resin (polymerizing w
ith calcium hydroxide)
Polymerization
Prisma ®
VLC –Dycal®

Advantages of Calcium hydroxide
✓Initially bactericidal then bacteriostatic.
✓Promotes healing and repair.
✓High pH stimulates fibroblasts.
✓Neutralizes low pH of acids.
✓Stops internal resorption.
✓Inexpensive and easy to use.

Disadvantage
✓Does not exclusively stimulate dentinogenesis.
✓Does not exclusively stimulate reparative dentin.
✓Associated with primary tooth resorption.
✓May dissolve after one year with cavosurfacedissolution.
✓May degrade during acid etching.
✓Degrades upon tooth flexure.
✓Marginal failure with amalgam condensation.
✓Does not adhere to dentin or resin restoration

Mechanism of action
•calciumhydroxidehasbeenrecommendedforuseinseveralclinicalsituations.
•Dependingonitsapplication,themodeofactionofCa(OH)
2mayvary.
(A)Antimicrobialactivity
(B)Mineralizationactivity
(C)Effectofliquidvehicle
(D)Asaphysicalbarrier
•Antibacterial activity
•Effects on endotoxins
•Antifungal activity
•Buffering effect of dentine on the antibacterial
activity of ca(oh)2
•Combination of ca(oh)2 and chlorhexidine

TRONSTAD ET AL (1981):
• Raise in ph
TORNECK ET AL (1983):
High phactivate alkaline phosphatase activity

ANTIBECTERIALACTIVITY
•Most of the endodontopathogensare unable to survive in the highly alkaline environment provided by
calcium hydroxide.
•Since the pH of calcium hydroxide →12.5, several bacterial species commonly found in infected root
canals are eliminated after a short period when in direct contact with this substance.
•Antimicrobial activity of calcium hydroxide is related to the release of hydroxyl ions in an
aqueous environment.
•Hydroxyl ions are highly oxidant free radicals that show extreme reactivity, reacting with several
biomolecules.
Siqueira Jr JF, Lopes HP. Mechanisms of antimicrobial activity of calcium hydroxide: a critical review (
Review). International Endodontic Journal, 32, 361±369, 1999

➢Theirlethaleffectsonbacterialcellsareprobablyduetothefollowingmechanisms:
1.Damagetothebacterialcytoplasmicmembrane
2.Proteindenaturation
3.DamagetotheDNA

(1)Damagetothebacterialcytoplasmicmembrane
Thebacterialcytoplasmicmembraneisresponsibleforessentialfunctionssuchas,
❖metabolism,
❖cellulardivisionandgrowth;andittakespartinthefinalstagesofcellularwallformation,
❖biosynthesisoflipids,
❖transportofelectrons
❖oxidativephosphorylation.

Thesefunctionstakenintoactionby,
(i)Selectivepermeabilityandtransportofsolutes;
(ii)Electrontransportandoxidativephosphorylationinaerobicspecies
(iii)Excretionofhydrolyticexoenzymes
(iv)BearingenzymesandcarriermoleculesthatfunctioninthebiosynthesisofDNA,cellwallpolymers,
andmembranelipids
(v)Bearingthereceptorsandotherproteinsofthechemotacticandothersensorytransductionsystems.
BrooksGF,ButelJS,MorseSA.Jawetz,Melnick,AndAdelberg'sMedicalMicrobiology,21stEdn1998.Stamford,
Ct:Appleton&Lange.

•Thus,peroxidesthemselvesactasfreeradicals,initiatinganautocatalyticchainreaction,
andresultinginfurtherlossofunsaturatedfattyacidsandextensivemembranedamage,
whichisasaponificationreaction.
Hydroxyl ions induce
lipid peroxidation,
resulting in the
destruction of
phospholipids,
Hydroxyl ions remove
hydrogen atoms from
unsaturated fatty acids,
generating a free
lipidic radical.
This free lipidic radical
reacts with oxygen,
resulting in the
formation of a lipidic
peroxide radical, which
removes another
hydrogen atom from a
second fatty acid,
generating another
lipidic peroxide.
Z Mohammadi,Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review;Chonnam Med
J 2012;48:133-140

(2)Proteindenaturation
•Cellularmetabolismishighlydependentonenzymaticactivities.
•Extracellularenzymesactonnutrients,carbohydrates,proteinsandlipidsthat,through
hydrolysis,favourdigestion.
•Intracellularenzymeslocatedinthecellfavourrespiratoryactivityofthecellularwallstructure.
•EnzymeshaveoptimumactivityandstabilityinanarrowrangeofpH,whichturnsaround
neutrality.

•The alkalinizationprovided by calcium hydroxide induces the breakdown of ionic bonds that maintain
the tertiary structure of proteins.
•As a consequence, the enzyme maintains its covalent structure but the polypeptide chain is randomly
unravelled in variable and irregular spatial conformation.
•These changes frequently result in the loss of biological activity of the enzyme and disruption of the
cellular metabolism.
•Structural proteins may also be damaged by hydroxyl ions.
Siqueira Jr JF, Lopes HP. Mechanisms of antimicrobial activity of calcium hydroxide: a critical review (
Review). International Endodontic Journal, 32, 361±369, 1999

(3)DamagetotheDNA
•HydroxylionsreactwiththebacterialDNAandinducethesplittingofthestrands.
•Genesarethenlost.Consequently,DNAreplicationisinhibitedandthecellularactivityisdisarranged.
•Freeradicalsmayalsoinducelethalmutations.
•Scientificevidencesuggeststhatthethreemechanismsmayoccur.Thus,itisdifficulttoestablish,in
achronologicalsense,whichisthemainmechanisminvolvedinthedeathofbacterialcellsafter
exposuretoastrongbase
.

AdjustmentofintracellularpHisinfluencedbyseveralcellularprocessessuchasthefollowing:
❖Cellularmetabolism
❖Alterationsinshape,mobility,adjustmentoftransportersandpolymerizationofcytoskeletoncomponents
❖Activationofcellularproliferationandgrowth
❖Conductivityandtransportthroughthemembrane
❖Isosmotic cellular volume
•Thus, many cellular functions can be affected by pH, including the enzymes that are essential for cellular
metabolism.

•It has been suggested that the ability of calcium hydroxide to absorb carbon dioxide may contribute to it
s antibacterial activity.
•However, cementum is permeable to water, ions and small molecules
.
. Hence, CO2 supply to remaining
bacteria in the root canal system may be maintained from the outside.
•In addition, bacteria located in ramifications have direct access to carbon dioxide from the periradicular
tissues.
•There is little reason to consider that calcium hydroxide impedes the carbon dioxide supply to bacteria.
Z Mohammadi,Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review;Chonnam Med
J 2012;48:133-140

EFFECTS ON ENDOTOXIN endotoxins do not cause cell or tissue
pathosisdirectly but instead stimulate
competent cells to release chemical
mediators
Macrophages are the main
target of endotoxins
Z Mohammadi,Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review;Chonnam Med
J 2012;48:133-140

During root canal treatment
LPS is released during multiplication or bacterial death, thus causing a series
of biological effects that lead to an inflammatory reaction and periapical bone
resorption.
In teeth with chronic periapical lesions, there is a greater prevalence of
Gram-veanaerobic bacteria disseminated throughout the root canal system
(dentinal tubules, apical resorptive defects, and cementum lacunae), including
apical bacterial biofilm.

Because these areas are not reached by instrumentation, the use of a root canal medicament is
recommended to aid in the elimination of these bacteria and to increase the possibility of clinical
success
The procedures and medicaments used in root canal treatment
should lead not only to bacterial death but also to the inactivation
of bacterial endotoxin

Anti-endotoxin studies of ca(OH)2

ANTI-FUNGAL ACTIVITY
✓Fungi have occasionally been found in primary root canal infections,
but they appear to occur more often in filled root canals of teeth in
which treatment has failed.
✓Candida glabrata, C. guilliermondii, C. parapsilosis, C. krusei,
C. inconspicua, C. dubliniensis, C. tropicalis, and
Saccharomyces species.
✓C. albicans fungal species most commonly isolated from infected root
canals.
Z Mohammadi,Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review;Chonnam Med
J 2012;48:133-140

✓It seems that the combinations of Ca(OH)2 with camphorated paramonochlorophenolor
chlorhexidinehave the potential to be used as effective intracanal medicaments for cases
in which fungal infection is suspected.
Z Mohammadi,Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review;Chonnam Med
J 2012;48:133-140

➢Siqueira et al. investigated the antifungal ability of several medicaments against C. albicans, C. glabrata,
C. guilliermondii, C. parapsilosis, and Saccharomyces cerevisiae.
➢They reported →the paste of Ca(OH)2 in camphorated paramonochlorophenol(CMCP)/glycerinhad the
most pronounced antifungal effects.
Z Mohammadi,Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review;Chonnam Med
J 2012;48:133-140

➢Valera et al. showed that, as an intra-canal medicament, CMCP was more effective against C.
albicans than Ca(OH)2 /CMCP paste.
Z Mohammadi,Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review;Chonnam Med J 2012;48:133-140

BUFFERING EFFECT OF DENTINE ON THE ANTIBACTERIAL ACTIVITY OF Ca(OH)2
❖The root canal milieu is a complex mixture of a variety of
organicinorganic
Hydroxyapatite
pulp tissue,
microorganisms,
inflammatory exudate
albumin
Z Mohammadi,Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review;Chonnam Med
J 2012;48:133-140

•Haapasaloet al. introduced a new dentine powder model for studying the inhibitory effect
of dentine on various root canal irrigantsand medicaments.
Conclusion
•dentine powder effectively abolished the killing of E. faecalis by Ca(OH)2 .
•Hydroxyapatite had an effect similar to dentine on Ca(OH)2 , preventing the killing of E. faecalis.
❖The substantial effect of dentine on the antibacterial activity of Ca(OH)2 can be attributed to the buffering
action of dentine against alkali.

•Both laboratory and in vivo studies have shown that buffering by dentine, particularly in the subsurface
layers of the root canal walls, might be the main factor behind the reduced antibacterial effect of Ca(OH)2
•It is possible that deeper in dentine (outside the main root canal), Ca(OH)2 is present as a saturated
solution or at concentrations even below that level.
•Besides dentine, remnants of necrotic pulp tissue as well as inflammatory exudate might affect the
antibacterial potential of endodontic disinfectants.

COMBINATION OF Ca(OH)2 AND CHLORHEXIDINE
•Chlorhexidine (CHX) is a cationic biguanide whose optimal antimicrobial activity is achieved with
in a pH range of 5.5 to 7.0
•Therefore, it is likely that alkalinizing the pH by adding Ca(OH)2 to CHX will lead to precipitation
of CHX molecules, thereby decreasing its effectiveness.
•When used as an intracanal medicament, CHX was more effective than Ca(OH)2 in eliminating
E. faecalis from inside dentinal tubules.
•Haenniet al. found no additive antibacterial effect by mixing Ca(OH)2 powder with 0.5% CHX.
They indicated that CHX had a reduced antibacterial action.
Z Mohammadi,Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review;Chonnam Med
J 2012;48:133-140

Ballalet al. (2007) found that 2% CHX gel was a more effective medicament than Ca(OH)2 past
e against E. faecalis.
Krithikadattaet al. (2007) reported that, as an intracanal medicament, 2% CHX gel alone was
more effective against E. faecalis when compared to Ca(OH)2.

THEORIES OF MINERALIZATION
The three theories are
• Alkaline phosphatase theory or booster theory
• Seedling theory or nucleation theory or collagen template theory
• Matrix vesicle theory

Alkaline Phosphatase theory or booster theory
✓It was introduced by Robinson in 1923.
✓It is also known as booster theory.
✓Here a booster mechanism such as an enzyme activity acts by raising the concentration of calcium
phosphate ions leading to precipitation.
✓It is considered that the soft tissue contains inhibitors of mineralization.
✓In order to initiate nucleation these same inhibitors have to be inhibited at the site of hard tissue
formation.

Once the nuclei are established, the level of
super saturation of the interstitial fluids is high
enough for the growth of hydroxyapatite crystal.
The energy needed for the nucleationis met by
elevatingthe local ionic concentration of
calcium ions and phosphate ions.
This is brought about by an enzyme known as
alkaline phosphatase. Hence this theory is
also known as alkaline phosphatase theory. This
process brings about homogenous
mineralization.
✓The energy required for
the formation of crystal
nuclei is higher than that
needed for continued
crystal growth.

OBJECTIONS
✓Based on an experimental study conducted on a diseased tissue.
✓Alkaline phosphatases seen in other tissues which do not calcify
✓Organic phosphate not sufficient to produce inorganic phosphate to initiate
calcification process.

MATRIX VESICAL THEORY
✓Discovered by Anderson &ErmannoBonucci
✓Matrix vesicalsare organelles of cellular origin that can be observed electron microscopically
in the matrix of cartilage, bone,&otherhard tissues
✓MVT states that ,due to presence of vesicles containing apatite crystals near each cartilage
cell which aggregate & form a matrix which is mineralised.

Mineralization within mesenchymal tissues
Initiationofmineralization Calciumhydroxideinducedmineralization
(B)MINERALIZATION ACTIVITY

Itisnowwidelyacceptedthatanepitacticmechanismoperatesfollowingtheinitialseedingofacollagenous
tissue.
•Onlycertaintypesofcollagen,suchasthosefoundindentineandbone,mineralizeinthisway.
•Theprocessisprobablytheresultofthejuxtapositionofchargedgroupsonadjacentmacromolecules
whichgiverisetotheepitacticcentres.
•Thesecentresrequireanucleationsitefromwhichhydroxyapatitecrystalgrowthcanproceed.
•Numeroustheoriesaboundastotheinitiatoroftheprocess.
Initiationofmineralization

•Some workers have implicated chondroitin sulphate as the seed whilst others, conversely, considered it
to be an inhibitor of mineralization.
•Other substances which have been postulated as initiators of mineralization include a vitamin D
dependent protein which is capable of binding calcium, phosphoproteins and phospholipids.
IrvingJ.T.EpitaxyDownTheAges.1981.Inthechemistryandbiologyof.mineralisedconnectivetissue,Elsevier
253-255.

•Ofequalimportancetotheinductionofmineralizationistheabilitytohalttheprocess.
•Onesafetyfactormaybethepresenceinthebloodandtissueofsubstancessuchaspyrophosphatei
onswhichactasinhibitors.
•Thisactionislostwhenpyrophosphatesaremetabolizedatthemineralizationsitesbypyrophosphata
se.
•Pyrophosphataseisamemberofthealkalinephosphatisegroup,whichmayexplainwhytheseenzyme
sareinvariablypresentinmineralizingtissues.
IrvingJT,WuthierRE.Histochemistryandbiochemistryofcalcificationwithspecialreferencetotheroleoflipids.
ClinicOrthopaedRelRes1968;56:237-260

Calciumhydroxideinducedmineralization

Histologicalperspective
HollandR.HistochemicalResponseofamputedpulpstocalciumhydroxide.ReviewOfBrasıLiaPesquiMedEBi
o1971;4:83–95.
(a)ZoneofObliteration
(b)ZoneofCoagulationNecrosis
(c)LineofDemarcation
(d)EarlystageofDentinBridgeFormation
(e)CalcificationoftheBridge

(a)ZoneofObliteration
•Thepulptissueimmediatelyincontactwithcalciumhydroxideisusuallycompletelyderanged
anddistortedbecauseofthecausticeffectofthedrug.
•Thiszoneconsistofdebris,dentinalfragments,haemorrhage,bloodclot,bloodpigments,and
particlesofcalciumhydroxide.
•Thiszoneofobliterationisdueto→thechemicalinjuryasaresultofhighconcentrationof
hydroxylionsandduetothehighpressureofthemedicamentapplication.(Schoderand
Granath1971)

(B)ZoneofCoagulationNecrosis
•Thetissuetogetherwithitsplasmaproteinswithinthezoneofobliterationtakesthe
bruntofthecalciumhydroxidechemicalthrust.
•Aweakerchemicaleffectreachesthesubjacent,moreapicaltissuesandresultsinazoneof
coagulationnecrosisandthrombosis,alsocalledSchroder’slayerof“firmnecrosis”and
Stanley’s“mummifiedzone”.
•Thiszoneis0.3–0.7mmthickandrepresentsdevitalizedtissuewithoutcomplete
obliterationofstructuralarchitecture.
•Outlineofcapillaries,nervebundlesandpyknoticnucleicanstillberecognized.

(C) Line of Demarcation
•Betweenthedeepestzoneofcoagulationnecrosisandthesubjacentvitalpulptissuethelineof
demarcationdevelops
•ThislineresultedfromthereactionofCHwithtissueproteintoformproteinateglobules
•Themigrationofinflammatorycellsbeginasearlyas6hrsafterinjury.

(D)ADanseZone(EarlyStageOfDentinBridgeFormation)
✓Immediatelysubjacenttothelineofdemarcationproliferationofmesenchymalcellsoccur
✓Within2-3daysaftertheinjury,connectivetissuefibresaccumalate
✓Atfirsttheyaredisorganised,consistingofbothfineandcoarsefibreslyingparalleltotheapplied
medicament
✓Theincreaseincollagenformationbecomesapparentat3-7days

✓The number of fibroblast, mesenchymal cells multiply sufficiently to present a modified cell rich layer
✓The cells within this layer gradually differentiate into pre-odontoblast and columnar shaped odonto
blasts.
✓By 7 days the matrix thickens and becomes more differentiated.
✓The replication of odontoblasts favored over fibroblast because of basic environment.

TheDentineBridge
•A mineralized barrier or 'dentine bridge' is usually produced following the application of calcium hydr
oxide to a vital pulp.
•This repair material appears to be the product of odontoblasts and connective tissue cells.
Histological Section -Arrow Shows Dentin Bridge Formation by Calcium Hydroxide

•Calciumionsreleasefromcalciumhydroxidestimulatesfibronectinsynthesisindental
pulpcells.
•Fibronectinmightinducethedifferentiationofdentalpulpcellstomineralizedtissue
formingcellsthatarethemaincellstoformdentinebridges,viadirectcontact.
Histological Section Showing Hard Tissue Formation Followed by 90 Days of Calcium Hydrox
ide Application

After 24 hrs
After 4-5 weeks
After 2-3 weeks
After 8 weeks

CALICIFICATION OF THE BRIDGE
A mineralized barrier or dentin bridge is usually produced following the application of Ca(OH)2.
Necrotic zone is formed adjacent to the material and the dentin bridge is formed between this
necrotic layer and underlying vital pulp .
Calcification occurs soon after the predentinhas developed.
The stage of tubular predentinformation may be reached in 2 weeks
After 1-3 month the barrier consists of more coronal layer of irregular osteodentinlike tissue with
cellular inclusions and the pulpal part consists of predentinlined with odontoblasts.

With this high Ph CH, bridge formation occurs at the line of demarcation
Over a period of time the coaguatednecrotic tissue above the line of demarcation degenerates
In case of lower PH such as dycalthe necrotic zone similarly formed, but is resorbed prior to the dentin
bridge which then forms to be directly against the capping material.
Dentinal bridge formed by high PH materials are histologically similar to those produced by lower PH materia
l but are easier to distinguish on a radiograph because of the space B/W the bridge and Ca(OH)2

❖Acc to Cox et al. 89 % of all dentin bridges contain multiple tunnel defects.
❖These multiple tunnel defects present a morphological distruptionof the dentin bridge barrier in that they
not only fail to provide a permanent barrier, but they also fail to provide a long term biological seal again
st bacterial infection.
❖Tunnel defects in dentinal bridge –allow the leakage of bacteria into pulp tissue and are a measure of
quality or sealing of the dentinal bridge. (peter murrayAJD 2006)

ASAPHYSICALBARRIER
•In addition to eliminating remaining viable bacteria unaffected by the chemomechanicalpreparation of
the root canal, intracanal medicaments have been advocated for other reasons.
•They should also act as a physicochemical barrier, precluding the proliferation of residual microorganis
ms and preventing the re-infection of the root canal by bacteria from the oral cavity.

Intracanal medicaments may prevent the penetration of bacteria from saliva in the root canal
basically in two ways
First, medicaments possessing antibacterial properties may act
as a chemical barrier against leakage by killing bacteria, thereby
preventing their ingress into the root canal.
Secondly, medicaments that fill the entire length of the root canal
act as a physical barrier against bacterial penetration.

✓Under ideal conditions, residual pulp tissue and the odontoblastic layer may form a matrix, such that the
subsequent calcification can be guided by the reactivated epithelial cell rests of Malassezor non periapical
pluripotent cells within bone.
✓Barrier formation also depends on the degree of inflammation and pulp necrosis, displacement at the time of
trauma, and number of calcium hydroxide dressings, which can complicate (or at least delay) treatment.

Under ideal conditions, residual pulp tissue and the odontoblastic layer may form a matrix, such that the subsequent calcification ca
n be guided by the reactivated epithelial cell rests of Malassezor non periapical pluripotent cells within bone.
Barrier formation also depends on the degree of inflammation and pulp necrosis, displacement at the time of trauma, and number of
calcium hydroxide dressings, which can complicate (or at least delay) treatment.
high pH, the highly reactive hydroxyl ions produce damage to the bacterial cytoplasmic membrane by denaturing protein and
destroying lipoproteins, phospholipids, and unsaturated fatty acids.
Consequently, these actions lead to bacterial vulnerability and alteration of the nutrient transport and DNA.
An alkaline environment neutralizes lactic acid from osteoclasts, avoiding dissolution of the dentin mineral components.
Calcium ions can induce expressions of type I collagen, osteopontin, osteocalcin, and alkaline phosphatase enzyme in osteoblasts a
nd mineralization through the phosphorylation of p38 mitogen-activated protein kinase and cJunN-terminal kinase
Alkaline phosphatase liberates inorganic phosphatase from phosphate esters.
It can separate phosphoric esters, releasing phosphate ions that react with bloodstream calcium ions to form calcium phosphate
of hydroxyapatite.

Bone morphogenetic protein-(BMP-)2is a growth factor that is expressed in presence of calcium hydroxide.
BMP-2 aids the regeneration of bone, cementum, and periodontal tissue.
Additionally, BMP-2 may bind to extracellular matrix type Iv collagen
Barrier formation

p38 mitogen-activated
protein kinase and cJun
N-terminal kinase
Barrier formation

Clinical applications of calcium hydroxide

1)CALCIUMHYDROXIDEASACAVITYLINER
✓The calcium hydroxide pastes are now in general use as lining materials.
✓Their perceived advantages, in addition to their therapeutic effects are as follows:
• 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 all
oys

•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
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

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 subs
equently 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 th
e other bases. These bases are used only for their therapeutic benefits, chemical
insulation or for retaining the sub bases.

INDIRECT PULP TREATMENT
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 remineralizedand hen
ce should be removed.
The inner carious layer is reversibly denatured but not infected and is capable of being remineralized
The technique

Response to the treatment:
Three distinct types of new dentin in response to indirect pulp treatment are seen:
• Cellular fibrillar dentin at two months post treatment
• Presence of globular dentin during the first three months
• Tubular dentin in amore uniformly mineralized pattern.

The histological evaluation:
The pulp reactions to the indirect pulp treatment are as follows:
Four layers have been demonstrated
1.Carious decalcified dentin
2.Rhythmic layers of irregular reparative dentin
3.Regular tubular dentin
4.Normal pulp with a slight increase in the fibrous elements.

Indirect pulp treatment: in vivo outcomes of an adhesive resin system
vs calcium hydroxide for protection of the dentin-pulp complex
(Falster et al.,2002)
protection of the dentin-pulp complex of primary molars with an
adhesive resin system results in similar clinical and radiographic 2-ye
ar outcomes as compared to calcium hydroxide when indirect pulp
treatment is performed in Class I composite restorations
Evaluation of indirect pulp capping using three different materials: A
randomized control trial using cone-beam computed tomography
(Mathur, et al.,2017)
Similar significant findings were obtained in radiodensity of barrier
formed (in HU). All three materials were found to be equally suitable
as IPC agents suggesting mineral gain
Clinical and radiographic evaluation of indirect pulp treatment of you
ng permanent molars using photo-activated oral disinfection versus ca
lcium hydroxide: a randomized controlled pilot trial
(MarwaAly Elchaghaby,2020)
The success for both groups was 100% clinically and radiographically
at all follow-up periods.
there was no statistically significant difference between both groups at
2, 6, 9, and 12 months
Supportive studies

Contradict meta-analysis
Is a calcium hydroxide liner necessary in the treatment of deep caries lesions? A systematic
review and meta-analysis
(da Rosa et al. Calcium hydroxide liner in deep caries lesions –a meta-analysis
International EndodonticJournal, 52, 588–603, 2019)

Conclusion
✓Although CH liner is commonly used by clinicians in deep carious lesion treatments, the availa
ble literature demonstrated that this material has no beneficial influence on the clinical success
of selective or stepwise removal of carious tissue.
✓For primary teeth, the level of evidence was moderate when CH liner was compared with GIC,
and low when it was compared with inert materials or adhesive systems.
✓For permanent teeth, evidence of very low quality indicated that CH liner would have no effect
on clinical success of deep caries lesion treatments.

Direct pulp capping treatment
•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.
•Three main calcium hydroxide products are: Pulpadent, Dycal, Hydrex(MPC).
Pulpadentpaste is considered to be most capable of stimulating early bridge formation.
Hydrexhas been considered that fast capable of forming a bridge
•Commercially available compounds of calcium hydroxide in a modified form are known to be
less alkanineand thus less caustic on the pulp.

Mineral Trioxide Aggregate (MTA) vs Calcium
Hydroxide in Direct Pulp Capping –Literature Review
Nawras Maher Mostafa, Shady Ahmed Moussa. Mineral Trioxide Aggregate (MTA) vs Calcium Hydroxide in Direct
Pulp Capping –Literature Review. On J Dent & Oral Health. 1(2): 2018. OJDOH.MS.ID.000508
Review –calcium hydroxide
-MTA
-`biodentin
-adhesive system
-zoe
-GIC/ RMGIC
Conclusion →MTA is more predictable than dycalin formation
of dentin barrier and superior in dentinogenesisprocess

Different materials for direct pulp capping: systematic review and
meta-analysis and trial sequential analysis
Falk Schwendicke, Clin Oral
Invest, April-2016
Conclusion →To
reduce risk of failur
e, dentists might
consider using
MTA instead of
calcium hydroxide
(CH) for direct cap
ping.

CALCIUM HYDROXIDE IN PULPOTOMY
• It is the most recommended pulpotomy medicament for pulpallyinvolved 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
Calcium hydroxide
Zoe

•Histologically pulp tissue adjacent to calcium hydroxide was first necrotized →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.

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
•At present calcium hydroxide pulpotomy technique cannot be generally recommended for primary teeth.
•recommended agent for carious and traumatic exposures in young permanent teeth, particularly with
incomplete closure.

Evaluation of formocresol, calcium hydroxide, ferric sulfate, an
d MTA primary molar pulpotomies
(EsmaYildiz,2014)
FC: formocresol, FS: ferric sulfate, CH: calcium hydroxide, an
d MTA: mineral trioxide aggregate)
→At 30 months, clinical success rates were 100%, 95.2%, 96.4
%, and 85% in the FC, FS, MTA, and CH groups, respectively.
Clinical and radiographic evaluation of biodentineversus calci
um hydroxide in primary teeth pulpotomies: a retrospective stu
dy
(Silvia Caruso1,2018)
Biodentineexhibited a higher clinical and radiographic success
rate compared to CH. However, besides the clinical results, bio
dentinehas some disadvantages, such as higher costs,
compared to CH.

Calciumhydroxideasarootcanalfillingmaterialforprimaryteethinpulpectomy
A comparison of calcium hydroxide/iodoform paste and zinc oxide eugenol as root filling materials
for pulpectomy in primary teeth: A systematic review and meta‐analysis
(NAJJAR ET AL. Clin ExpDent Res. 2019;5:294–310)

Conclusion→ due to its resorbable property, Ca(OH)2/iodoform is the best filling material to
be used for pulpectomy in primary teeth nearing exfoliation.
Conversely, either ZOE or ZOE/iodoform combined with Ca(OH)2 is the materials of choice for
pulpectomy in primary teeth need long time before exfoliation

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.

•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.

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 hydroxi
de and CMCP.
•Commercial paste of calcium hydroxide (eg.Calasept, Pulpdent, Hypocal, Calyxl) may
be used to fill the canals.
•Histologically →formation of osteodentinafter placement of calcium hydroxide paste

•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.

Time required for apical barrier formation in apexification using calciumhydroxide
Sheehy and Roberts1997 an average length of time for apical barrier formation ranging from 5
to 20 months
Finucane and Kinirons1991 calcium hydroxide apexification and found that the mean time to
barrier formation was 34.2 weeks (range 13–67weeks)
Cvek 1972 infection and/or the presence of a periapical radiolucency at the start
of
treatment increases the time required for barrierformation
Kleierand Barr1991 presence of symptoms the time required for apical closure was
extendedby approximately 5 months to an average of 15.9months

Apexification with the use of calcium hydroxide
(R Nahar,2012)
calcium hydroxide dressings is a justified alternative for the
biological sealing of an extensive foraminal opening, with conco
mitant repair of periapical lesions and continued calcific barrier
formation.
Successful closure of the root apex in non-vital permanent inciso
rs with wide open apices using single calcium hydroxide (caoh)
dressing
(NB Nagaveni,2010)
single application of CaOHdressing is sufficient to induce
apical barrier formation in young pediatric patients having pulpl
essteeth with wide open apices.
Apexification with Calcium Hydroxide: 27 Months Follow Up
of a Case
(Chowdhury AFMA,2013)
calcium hydroxide has proven its ability in apical healing and
stop formation by stimulation of Hertwig’sepithelial root sheath
and(or) its remnants, the cell rests of Malassez. The extruded
material was also well accepted by the periradiculartissue.

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.

•Direct contact experiments in vitro require a 24 hour contact period for complete kill of enterococci.
•Calcium hydroxide not only kills bacteria, but it also reduces the effect of the remaining cell wall mat
erial lipo-polysaccharide.
•It should be mixed to a thick mixture to carry as much Calcium hydroxide particles as possible. This
slurry is best applied with a lentulo-spiral.

•calciumhydroxide→abilitytodissolvenecrotictissue(periapicalinfection)
•Calciumhydroxideisnowwidelyusedtoreducetheseepageofapicalfluidsintothecanal
soastoallowtheplacementofasatisfactoryrootfilling.
•Themechanismwherebythereductionofseepageoccursisprobablyduetothefibrous
barrierthatisformedwhencalciumhydroxideisplacedindirectcontactwithhosttissues,
ortothecontractionofcapillaries,assuggestedbyHeithersay,orsimplytotheeffectof
mechanicalblockage.

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.
•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.
•Recent uses → sealapex(kerr), apexkit(vivadent).

•Comparative studies reveal their mild cytotoxicity, but their antibacterial effects are variable.
•Further research is required to establish the tissue healing properties of calcium hydroxide in
root canal sealers.

OTHERCLINICALAPPLICATIONSOFCALCIUMHYDROXIDE
Horizontal root fractures
✓first recommended by Cvek(1974)
✓proposed that → the canal at the level of the fracture line was comparable to the apical foramen of an
immature tooth. Thus, he assumed that the repair would be similar to the apexification procedure
employed for a tooth with an open apex.
✓drawback→ chair-side time and the frequent refilling of the canal with calcium
hydroxide
✓A better alternative treatment protocol is now available with use of MTA

Perforations
•It has been suggested that large apical perforations should be treated in a similar way as teeth
with immature apices, i.e. with long-term Ca(OH)
2treatment to achieve a hard-tissue barrier.
•El Deebet al. and Himelet al.
(1985)
expressed concerns about using Ca(OH)
2in close proximity
to the attachment apparatus because of the necrotizing properties of the material and the
inflammatory reaction to it.
•MTA widely used

Rootresorption
•Frank & Weinereported on a technique using a Ca(OH)
2-camphorated monochlorophenol
mixture for the nonsurgical treatment of perforating internal resorption.
•In such situations, other similar techniques have been used that resulted in the deposition of a
cementum-like or osteoid tissue.
initial treatment of choice → for internal root resorption is to pack the canal and the
resorption lacuna with Ca(OH)
2paste. The Ca(OH)
2will tend to necrotize remaining tissue in the
lacuna, and the necrotic remnants are then removed by irrigation with sodium hypochlorite.
•Ca(OH)
2should be placed into the resorptive defect at 3-month intervals until there is evidence
of hard-tissue repair

•Whenexternalresorptionoccursfollowingluxationinjuriespulpextirpation,debridementand
Ca(OH)
2therapyarenecessary.
•Insomesituationswhenrootresorptioncontinuesafterthecompletionofactiveandretentive
phasesoforthodontictreatment,intentionalpulpextripationandCa(OH)
2isoftensuccessfulin
abatingresorption.
•Andreasenwasabletoarrestinflammatoryrootresorptioninnineoftencasesusingan
intracanalCa(OH)
2dressing.

Conclusion
•Calcium hydroxide has been around the century and the research surround it’s properties and use, has
increased dramatically in the recent years. Many newer materials are now available in the market,
which claim to be superior to calcium hydroxide.
•When compared to the prices of the newer materials calcium hydroxide is more cost effective. Some
preparations of calcium hydroxide are still, expensive but a simple calcium hydroxide powder and
sterile water can serve many purposes and works out to be reasonable and affordable to many patients.
•Hence calcium hydroxide has become one of the most widely accepted materials and remedy to most
of the problems due to its high pH and Antibacterial property.

Calcium hydroxide in pediatric dentistry

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Calcium hydroxide in pediatric dentistry

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