clean n shape

7/30/2019 Clean n Shape

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cleaning and shaping

Martin wadakkan


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Introduction

Bio mechanical preparation

Disinfection

Obturation


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Straight line access

Exploration of the canal

Eextirpation debridement of necrotic

tissues

instrumentation, irrigation and

debridement and disinfection of the

canal


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Cleaning and Shaping

remove the contents of the canal in such a

way that a clean obturation is achieved .

Instruments shape irrigants clean

Baumghartner & Madder


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Cleaning Removal of all contents of the root

canal , microflora, dentinal debris etc

instruments

the irrigating systems and medicaments

Shaping a specific canal form to ensure a

3 D obturation .


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History of Cleaning and Shaping1893 - EmilSchreier-mixture of alkali metals for

cleaning and disinfecting root canal

1894 - DrCallahanused Sulphuric acid within

canals to clean root canals1900 - DrHarlan-Papain for digesting dead

tissues

1917 - DrHermann Prinz- 1% sodium chloride

during electromedication1941 - Dr Louis Grossman - 5.25% sodium

hypochlorite dissolved pulp tissue in vitro


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Schilders Mechanical Objectives

A continuous conicaltapering shape

narrowest cross sectional areaapical constriction

multiple plane preparation

never transport the foramenkeep the foramen as small as

possible


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Objectivesof Cleaning andShaping Biologic

to free the root canal from pulp tissue

bacteria and their endotoxins

infected dentin & necrosed tissues


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Armamentarium forcanalpreparationInstruments

Cleaning reagents


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Cleaning reagents, Devices and

Indicators

Idealirrigant

Kills bacteria and inactivates endotoxins

Dissolves necrotic tissue

Lubricates the canal

Removes the smear layer

Does not irritate healthy tissues


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Sodium Hypochlorite Effective against Enterococcus, Actinomyces

and Candida organisms

Various concentrations range from 0.5% to5.25%

0.25% NaOCl kills Enterococcus Faecalis in 15mins

1% NaOCl kill Candida Albicans in 1 hour

Lower concentrations dissolve mainly necrotic

tissue Higher concentrations allow better tissue

dissolution but dissolves both necrotic and vitaltissue

JoE;32,5;2006/JoE16:580,1990/IEJ 34:429,2001


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Sodium Hypochlorite To increase the efficacy of NaOCl

Lower the pH

Increase the temperature

Ultrasonic activation of sodiumhypochlorite

JoE 32;5;2006/OOOOE 94;76:2002


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Chlorhexidine Broad spectrum Antibiotic

Its use as an endodontic irrigant is based on its

substantivity

Binding to Hydroxyapatite Long lasting antimicrobial effect

2% conc used as irrigant

Unable to dissolve necrotic tissue Less effective of gram negative than on grampositive

JoE 32;5:2006


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Chlorhexidine CHX + Ca(OH)2 show strong antibacterial

activity against obligate anaerobes

CHX did not affect the alkalinity ofCa(OH)2

CHX useful as a final irrigant

JoE 32;5:2006


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Iodine Potassium Iodide IKI kills a wide spectrum of micro

organisms

Low toxicity

Acts as an oxidising agent againstsulfhydryl groups of bacterial enzymescleaving disulfide bonds

Combination with CHX kills Ca(OH)2resistant bacteria more effectively

Possible allergic reaction


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M T A D Mixture of Tetracycline isomer (doxycycline),

Acid (citric acid), Detergent (tween 80)

Removes smear layer

More effective in apical third than EDTA +NaOCl

Less destructive to tooth structure than EDTA

when used as final irrigant

JoE 29;3,2003


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E D T A Forms stable calcium complex with dentin

mud, smear layer and calcific deposits andprevent apical blockage

Negotiating narrow, calcified canals andto establish patency

Chelators detach biofilms adhering to root

canal walls

JoE 32;5:2006


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E D T A Calcium binding releases protons and EDTA

loses efficiency in acidic environment

Effervescence or bubbling effect

EDTA reduce available chlorine in NaOCl

So, EDTA should not be mixed with NaOCl

Hydroxyethylidene bisphosphonate (Etidronate)

decalcifying agent Alternative to EDTA as itshows less interference with sodium

hypochlorite

JoE 32;5:2006


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Other Irrigants used Calcium Hydroxide (requires prolonged

exposure)

Hydrogen Peroxide

Salvizol (N1decamethylene- bis-4-aminoquinaldinium diacetate)

Advocated use of0.5% CHX and NaOCl asirrigant can overcome effect of dentin dust onconventional medicaments


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Suggested Irrigation Regimen Hypochlorite solution should be employed

throughout instrumentationwithout altering it

with EDTA. Canals should always be filled with

Naocl. This will increase the working time ofirrigant and cutting efficiency of hand

instruments is increased(JOE 1990, 16 418-22) and

torsional load on rotary NiTi instruments is

improved (IEJ 2005, 38, 223-29) Between instruments copious irrigation with

NaOCl recommended


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Suggested Irrigation Regimen[continued]

Once shaping is completed canals can be thoroughlyrinse with EDTA for about 1 min. Prolonged exposurewith EDTA may weaken the root dentin(JOE 2002, 28, 17)

After removing smear layer final rinse with antisepticsolution appears beneficial. The choice of final irrigantdepends upon the next treatment step.

Ifintervisit dressing is planned like calcium hydroxide,the final rinse should be Naocl as these chemicals areperfectly complementary (JOE 1998, 24, 326).


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Alternative concepts Use of Laser light

Electrochemically activated water

Ozone gas infiltration

None of these approaches can match NaOCl

Reducing surface tension of the solutions mayincrease the penetration into dentinal tubules

JoE 32;5:2006


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Indicators Ruddle Solution/Visualisation Endogram

5% NaOCl

Hypaque

17% EDTA

Clinicians use Endograms to visualizemicroanatomy, verify the shape and

monitor remaining root canal thickness Visualising caries, certain fractures,

missed canals and leaking restorations


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Ultrasonics Ultrasonics use sound as an energy source resulting in a

three dimensional activation of the file

Alternating attractive and repulsive forces between theplates affect the mechanical vibratory movements, whichare then transferred to the instrument

Ultrasonics are available as two designs, either

Piezoelectrical

Magnetostrictive

Endosonic ultrasonic synergistic system is a termcoined to describe combined use of ultrasonics ininstrumentation and irrigation


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Ultrasonics Druttman and Stock pointed out, "with the

ultrasonic method, results depended on

irrigation time. The cleanest canals are

achieved by irrigating with ultrasonics andsodium hypochlorite for 3 minutes after the canal

has been totally prepared (IEJ 1989, 20, 233)

James O. Johnson found that 2% CHX was

significantly superior to 5.25% NaOCl withirrigation alone and with final passive ultrasonic

activation(JOE 2003, 29, NO 9).


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Sonics Sonic systems uses vibration in audible

frequency range for activation of endodontic files

Three sonic files used are Rispisonic, shapersonic, Trio sonic

When loaded in canal produces longitudinal, up

and down motion

Disadvantanges include perforations,transportation


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Sonics Dummer et al the Shaper Sonic files widened the canals

more effectively than the Rispi Sonic files, whilst the TrioSonic files were particularly ineffective

At the University of Minnesota, the ultrasonic units wereagain tested against the sonic unit. The researchersfound the Micro Mega Sonic to be betteras they werethe fastest in preparation time and caused the "leastamount of straightening of the canals.

The sonic technique extruded the least and hand

instrumentation the most debris. Ultrasonic was halfwaybetween.

IEJ 1989, 22, 211/ JOE 1989, 15, 235


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