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Nidambur Vasudev Balla
Gopal Venktesh Shavi,Ranjith Kumar,
Mala Kundabala.
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y Calcium hydroxide used -1920s.
y Introduced by Hermann.
clinical applications
y an antimicrobial agent,
y controlling exudates from root canals,
y arresting inammatory root resorption,
y inducing calcic response,
y root canal sealer.
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y MOA
By dissociating into calcium and hydroxyl ions
increasing pH locally (Tronstad et al) .
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Benecial effect is due to
y Break up of fatty acids in gram-negative bacteria,
y inactivation of endotoxins,
y damage to the bacterial DNA
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y Efcacy [Ca(OH)2]
availability of hydroxyl ions in solution
dependent on vehicle that is used.
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y Medicament vehicle very imp. role in overalldisinfection
y determines velocity of ionic dissociation,
y enable paste to be solubilized / resorbed at
varying rates.
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y Lower the viscosityhigher ionic dissociation .
y High mol. wt. of common vehicles
minimizes dispersion into the tissue
maintains paste in desired area for longer
duration .
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Three main types of vehicles used:
(1)water soluble substances
water, saline, local anesthesia, ringers solution
(2) viscousvehicles
glycerin, polyethylene glycol, and propyleneglycol (PG)
(3) oil-based vehicles olive oil, silicone oil, camphor, eugenol,
metacresylacetate
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y In 1982,
yAnthony et al studied effect of vehicles on pH ofcalcium hydroxide.
y Concluded that calcium ions diffuse throughapical foramen and change the PH.
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y Chitosan natural polysaccharide widely usedpharmaceutic excipient.
y synthesis -partial deacetylation of chitin,
y derivative of exoskeleton of arthropods.
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y copolymers of glucosamine and N-acetyl glucosamine .
biological actions:
y hypocholesterolemic
y antimicrobial
y wound healing
y mucoadhesivey sustained release
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y products available as powder, paste.
y combined with collagen sponge as a barriermembrane in periodontal therapy
y an oral mucosal delivery agent for chlorhexidineagainst Candida albicans .
y Ballal et al
y chitosan enhanced sustained release of chlorhexidinegluconate against Enterococcus faecalis.
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y Guar gum gum from ground endosperms -cyamopsis tetragonlolbus.
y highmol.wt. hydrocolloidal polysaccharide ofgalactose and mannan units.
y used in cosmetics, food products and pharmaceuticformulations as a binder and thickening agent
y Has a sustained release property (George and Abraham)
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y Chitosan (85% deacetylated) Sigma-AldrichChemicals, Taufkirchen, Germany.
y PG, polyethylene glycol 6000 (PE 6000), and guar gum( Universal Lab. Mumbai, India).
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y Hydrophilic polymers
y PG, PEG 6000, chitosan, and guar gum were used .
y Different concentrations of hydrophilic polymers for desired release of calcium ions
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y Ethical clearance Ethical Committee (IEC 008/2009)of Manipal University, Manipal, Karnataka, India.
y 40 human maxillary anterior teeth ---extracted for
periodontal reasons .
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y Soft-tissue remnants on tooth surface -removed usinga soft brush.
y Teeth examined for fractures, cracks, or any otherdefects using magnifying loupes.
y Teeth stored in solution of 0.05% sodium azide innormal saline at 4 degree C
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y Solution changed daily until sufcient number ofsamples were collected.
y The crowns of all the teeth were removed at the CEJ
using a diamond disc 15 mm.
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y The root canal was enlarged initially up to size 20using K-les , and the pulp tissue was removedusing barbed broach.
y working length of the root canal was determined .
y each tooth was instrumented upto size 45 apically.
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y Coronally the canal was enlarged using G. G .drillsno. 2 to 5.
y After each instrument, the canal was passively
irrigated with 2 mL of 2.5% NaOCl .y The nal irrigation was performed with 2 mL of
17% EDTA solution
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y Finally, the root canal was ushed with 5 mL ofdistilled water .
y The teeth were then divided into four group :
group 1PGgroup 2 PEG 6000
group 3 chitosan
group 4guar gum
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y A vial method was adopted .
y Accurately measured quantities of differentformulations were performed to the root canal using
K-les up to 1 mm short of the working length.y The formulations were further condensed with an
endodontic nger plugger.
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y While lling the root canals, each root was held in amoist gauze to prevent the smearing of theformulations onto the root surface .
y
The orice of the root canal of all the teeth was sealedwith GIC
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y The teeth were then suspended in the glass vials -10mL of distilled water.
y the pH and the calcium ion concentrations weremeasured.
y
Solutions of 3.0 mLwere then withdrawn periodicallyat predetermined time intervals up to 24 hours and at7, 15, and 30 days.
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y The vials were tightly closed with the help ofmolding wax.
y The solutions were analyzed using an ultraviolet
spectrophotometer at 220 nm .
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y The change in pH of all the different formulationswas determined by pH meter
y Each sample was tested three times, and the mean
value for each experimental group was calculated
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y PG showed cumulative drug release of 96.64%
0.56% at the end of 15 daysy PEG 6000, chitosan, and guar gum showed cumulative
drug release of 98.22% 0.25%, 86.88% 0.68%, and96.03% 0.42%, respectively, at the end of 30 days.
y Among all the formulations tested, chitosan showed acumulative drug release of 86.88% 0.68% for aperiod of 30 days
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y The pH of different groups on rst day was found to be7.0.
y After 30 days, pH was found to be 10.3, 10.7, 10.2, and11.2.
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y The imp. of the alkalinizing effects of calciumhydroxide and its capacity to produce OH ions in theperiapical environment has been reported
y Nerwich et al pH changes in root dentin over a 4-week period and considered as a reasonable timeinterval to expect effective therapeutic benets .
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y Placing a formulation of calcium hydroxide with anappropriate vehicle, which can sustain high alkalinepH in the periapical area.
y In the present study, all the formulations showed ahigh alkaline pH (>10) at the end of 1 month.
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y The dissociation of calcium hydroxide in differentvehicles has been shown to be the most efcient way torelease hydroxyl ions .
y
Vehicles can also prolong the duration of the drugeffect signicantly and improve the bioavailability ofthe drug
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y an ultraviolet spectrophotometer was adoptedbecause of its rapid analysis and the cost of the
analysis is less expensive
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y All the vehicles used in this study to prepare thecalcium hydroxide gel were biodegradable.
They offer many advantages
y targeting the drug to the specic sites,y controlled release of the drug,
y protection of either the host or the encapsulated drug.
y the drug release rate can be controlled by the selection
of the mol. wt .of the polymer and its compositions
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y chitosan is the second most abundant organic materialnext to cellulose .
exhibits favorable biological properties such as
y nontoxicity,y biocompatibility,
y biodegradability has attracted much interest inpharmaceutic research as a polymeric drug carrier
y as a novel drug absorption enhancer across nasal andintestinal epithelia
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y The release pattern with chitosan was biphasic inmanner.
y The burst release of calcium ions with chitosan in the
initial stages could bey to the drug present at the surface of the polymer.
y because of the presence of free amino groups
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y Chitosan when used as a vehicle exhibited a controlledrelease of calcium ions .
y All four vehicles maintained a high alkaline pH at the
end of 1 month.y the effect of degradable products on the penetration
of intracanal medicaments, sealers, or adhesive resinsinto the dentinal tubules has to be evaluated.
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