DM Lec#7 By Atheer Faris

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DM Lec#7 By Atheer Faris

Post by Sura on 6/11/2011, 9:54 pm

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Sura

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تاريخ التسجيل : 2010-09-29

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Re: DM Lec#7 By Atheer Faris

Post by Shadi Jarrar on 8/11/2011, 9:15 pm

Endodontic materials
Root canal irrigants &medicaments
The main objectives of root canal therapy :- 1-removal of pathologic pulp.
2-cleaning &shaping of the root canal system.
3- 3D obturation to prevent reinfection.
If we successfully do these 3 objectives ,we have successful RCT.
mechanical instrumentation alone can`t ensure complete prepare &remove of pulp tissue(inflamed or necrotic )or total remove of bacteria.
so what do we use?
we use Chemicals like irrigants to remove all the contents of the canal (necrotic tissue ,inflamed tissue ,bacteria)
-irrigation is an essential part of root canal debridement Because it allows for cleaning beyond what might be achieved by root canal instrumentation alone.
-we can`t reach to total sterilization of the canal (theortical term) We reach state of disinfection by using :
1-irrigants : chemical solution we use it while doing cleaning & shaping by files (during the appointment)
2-medicaments :chemicals paste or gel that placed in canals (between visits) .
Irrigants
Properties of irrigants according to its functions:
1-antimicrobial (to kill bacteria)
2-dissolve organic debris (to remove tissue)
3-lubricant (when we put &remove files no heat result.
4-cheap
5-biocompatabile (not toxic &don`t affect on tissue).
6- flushing (when we do irrigation all debris go out from canal with irrigant.
Functions of irrigants:
""file shape the canal& irrigant clean the canal""
1-Lubrication of instruments used to shape the canal.
2-flushing out of gross debris.
3-dissolution of organic &inorganic tissue.
4-antimicrobial effect.
If you do perfect shaping & use perfect gutta-percha & you don`t use irrigant what will happen??


The RCT failure in general may be due:
1-no good condensation
2- you don`t reach full working length.
3-you don`t use rubber dam (no isolation)
4-microleakge
5-you don`t use irrigation



That is failure because you don`t kill bacteria #(
Bacteria don`t need big space to exit( microns) so we do good shaping &tapering to do good cleaning & go more deeply to kill bacteria.
Phenol based agents , aldehydes &halidyes
Like: cresol, formacresol, chlorine….etc-
- They are excellent antimicrobial agents but it has problem that they aren`t selective to bacteria; they would destroy any living tissue (kill bacteria, pulp &periapical tissue)
-possible mutagenic & carcinogenic effect.
-highly toxic &we can`t confined its action just inside the canal that mean it work inside &outside the canal & when we put it leave it 1-2 weeks….where will it reach?????
-we try to move away from these agents & use the substituents (we will talk about it in the sheet)
Classification of irrigants
A-Chemically Inactive irrigants
-Its chemical composition or structure doesn`t affect on our work.(don`t have any chemical activity)
# sterile Water
#Saline(water+salt) that we use in the clinics
#Local anesthesia
-they do flushing of debris outside &don`t kill bacteria &don`t have dissolution of tissue property.(they do irrigation & lubrication& flushing)
B-chemically active irrigants
#sodium hypochlorite(NaOCl)
#Oxidizing agent as H2O2
#Chelating agent as EDTA
-they have lubrication &dissolution & other effects.
1- sodium hypochlorite(NaOCl)
-0.5-5.25%
??What is the recommended concentration??
increase active ingredient or NaOCl concentration increase the efficacy increase toxicity.
Decrease the concentration (more safe but less effective ).
You have to reach the balance between effectiveness & safety ( no specific concentration)
-it is antibacterial ,antifungal.
-excellent tissue dissolving ability .
-the best irrigant until now.(doesn`t have all properties but still the best.)
-heat enhance efficiency so if you heat it from 25 c (room temperature )to 37 c( body temperature) you increase the efficacy .
-it has effect on mechanical properties of dentine (make dentine weaker)because it causes dissolution but it can`t remove smear layer
We remove smear layer because it cover dentinal tubules which contain bacteria so we remove it & use irrigator &reach inside dentinal tubules & kill bacteria.
-apical reaction: it happens accidentally when we put the needle of irrigator syringe it should be lose & you move it in & out .it shouldn`t trap in canal or reach the apex because if NaOCl get beyond the apex .during seconds swellings &blue to purple color happen to the patient (be carful ).
The management of this accidental case::-
1-reassure your patient that don`t be afraid because it isn`t life threatening .
2- try to do irrigation with water to remove NaOCl as much as we can.
3- give steroids there is swelling & pain .
4-in very sever cases the patient need hospitalization.
-apical reach mean when NaOCl reach the apical region it destroy the tissue & make sever inflammation &edema& swelling take place within short time.
2-Hydrogen peroxide H2O2
-used very less nowadays(very little using)
-it makes bubbles & these bubbles do flushing effect.
-destructed anaerobic bacteria .
3- chlorhexidine (CHX)
-TRADE NAME: Hibiscrub
-usually found in mouthwashes like Corsodyl in 0.2% concentration
-it doesn`t dissolve tissue
-it has very good anti bacterial effect so they use it in periodontal treatment like ( gingivitis,pockets).
-substantivity: antimicrobial effect stay after application to sometimes up to 12 week.
-should be used as final rinse (that mean we put it & dry with paper points without using any thing after it ) because it doesn`t dissolve tissue & it has substantivity effect.
Until now nothing remove smear layer ,&we have to remove it by using EDTA
4-EDTA
-ethylene diamine tetracetic acid
-removes smear layer , soft dentine &doesn`t kill bacteria .
-we use it in combination with NaOCl because:
NaOCl: kills bacteria ,doesn`t remove smear layer.
EDTA :removes smear layer ,doesn`t kill bacteria.
5- MTAD
-introduce by torabinejad in California in 2003.
-trade name : BioPure
- to find ideal irrigant it is mixture of:
3%doxycycline(antibiotic to kill bacteria )
4.25% acid : sitric acid (to remove smear layer)
detergent (0.5% polysorbate 80)to decrease surface tension & get good wetability& enter all canals.
-good antimicrobial ,its substantivity up to 4 week.
-they found it`s not good substitute to NaOCl (the best irrigant)but we can use it instead of EDTA because it contains acid .
-EDTA =citric acid .they act as chelating agent .
Chelating agent: agent remove Calcium from tissue & when it remove Ca the tissue become soft.
-best irrigation protocol is the alternating use of NaOCl with EDTA or BioPure& CHX is final rinse.
-irrigant have to be used in large volumes & confined to root canal space never beyond the apex or outside the pulp champers (we use large suction to take any irrigant come out of tooth). Never to be delivered with excessive force.
Note: when there is perforation in canal or wide canal (immature young canal ) in children we don`t use NaOCl because of probability of accident ;we use CHX alone.
Irrigation delivery & agitation techniques:
A-Manual technique
1-syringe irrigation with needle :we have to use small needle to go inside the canal not like what we have in the clinic because the irrigation just reach 2-3 mm below the tip of needle
2-brushes : we have manual brushes used after irrigation ;we put it inside the canal & do agitation .
3- manual –dynamic irrigation: we prepare the canal & put irrigation inside it & use well fitted gutta-percha same size of the canal & do irrigation.
B-machine –assisted technique :
1-rotary brushes
2- continuous irrigation during rotary instrumentation .some rotary instrument or files come with it its own irrigator .
3-sonic irrigation
4-ultrasonic irrigation
There is solution inside the canal & we put files with sonic tip & we turn on the machine.
INTRA CANAL MEDICAMENTS
-a medicament is an antimicrobial agent that is replaced inside the root canal between treatment appointments in attempt to destroy remaining microorganisms & prevent reinfection.
Functions of intracanal medicaments
**Primary function: antimicrobial activity (most important
-antisepsis
-disinfection
**Other functions :
-hard – tissue formation
In case of apexification :at the beginning of the tooth eruption the apex is opened & need 3 years to close. so during these 3 years if there is caries or trauma or necrotic tooth … we can`t do RCT to open apex tooth because we need apical stop to put gutta-percha. the management differ from the past.
We do cleaning , shaping , widening of the canal then we put aqueous non –setting calcium hydroxide inside the canal for about 1.5 years & every 3 months we change it .it help in closing the apex not forming the apex by act as calcific barrier.
-pain control ( some medicaments contain steroid )
-exudation control ( stop fluid formation)
-resorption control
When we do cleaning & shaping & putting non-setting calcium hydroxide almost all types of resorption ( internal resorption caused by vital tissue or external resorption by osteoclast)will stop.
- Non-setting calcium hydroxide is solution (suspension) & no setting happen
-calcium hydroxide we use as liner in clinic is hard setting calcium hydroxide)
Ideal properties
-anti bacterial
-penetrate dentinal tubules & kill bacteria inside it
-control exudation or bleeding
-biocompatible ( no effect on tissue)
-eliminate pain
-radio-opaque
-doesn`t stain tooth
-cheap
-no effect on temporary ( from handout)
In the past the dentist didn`t use to leave the canals empty always put medicament.
-recent research (in 2009) that did on patient explain that no clear evidence of the effect of medicament on the quality of treatment because we have very complex root canal anatomy & poly microbial nature of root canal infections ( up to 100 type)
- some dentists use medicaments & others don`t use
- calcium hydroxide
-Trade name :hypocal
-PH=12 ( it has alkaline effect)
-disruption of DNA synthesis & cell membrane so it kill bacteria .
- it form layers of calcium hydroxide & layers of bacteria.the layer that is beyond calcium hydroxide even it is living tissue will die ,we call that sterile necrosis.
-about calcific barrier
In open apex tooth we put calcium hydroxide the first layer of periapical tissue will be necrotized ( sterile necrosis mean death of periapical tissue & stop the infection)due to alkaline effect then mineral deposition will happen & calcific barrier form.
-denatures protein
-cheap
-dry weeping canal ( stop fluid s in canal)
Weep . نحيب درجة من البكاء
-form calcific barrier ( it need 1.5 years) nowadays we don`t use this calcification there is something else to use.
The substituent of formcresol is ledermix.
Ledermix is combination of (antibiotic to reduce infection)+(steroid to reduce pain )>>not available in JORDAN
- chlorhexidine (CHX)
We talk about its substantivity .usually in reinfection or retreatment (RCT failure) the type of bacteria differ from the type of that cause original infection . E.Faecalis : one of the causes of RCT failure & most resistance type so we use CHX in retreatment cases to kill this bacteria.
-Antibiotics
-it has problems: allergy ,resistance of bacteria strain
– patient with post-operative pain or swelling or abscess we don`t give antibiotic.
-95%of cases never given antibiotics
**Abscess :we do drainage either through canal ( do initial good cleaning & shaping)or mucosal incision.
**post- operative pain ( after RCT) : we give analgesic not antibiotic.
**swelling : the patient should come to you & see if this swelling is
a- abscess ( incision &drainage),
b- cellulitis ( diffuse, fever, febrile ,hotness ) you give antibiotic
-you give antibiotic in systemic manifestations like : fever ,general malaise ,immunocompromized .
-note : if there is remaining root & there is abscess ; you do drainage then extract .
Abscess is balance between bacteria & body defense. when you do drainage you enhance & help body defense so you can give anesthesia & extract it.

"كل عام وانتم بألف خير"

ATHEER AL-KHARABSHEH

Dental material sheet # 7

30-10-2011
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Shadi Jarrar
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عدد المساهمات : 997
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تاريخ التسجيل : 2009-08-28
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