OBTURATION

Dr Deepti SainiSchool of Dental SciencesUSM

Topics to be covered1. Obturation a. Definition b. Objectives c. Assessment d. Apical extent of root filling -Overfilling, Underfilling e. Instruments2. Root Canal filling Materials a. Ideal properties b. History c. Types – Pastes Semisolids – GP with sealants (Classification of

techniques and brief discussion) Solids3. Gutta Percha Removal

1. a) What is Obturation..?

• Obturate – to close or obstruct

• Final step in endodontic treatment - sealing of apical foramen at CDJ & all portals of entry to periapical tissue with an inert material.

c) Assessment before obturation

• Tooth properly isolated to eliminate risk of canal contamination

• Compacting instruments must be prefitted into canal

• Moisture free prior to obturation• In multirooted teeth, all efforts must be

expended to ensure that all the canals have been cleaned and shaped properly.

When to Obturate….?• Adequate biomechanical preparation has

been completed & confirmed.

• Tooth is asymptomatic

• Canals are dry

• No sinus tract

• No foul odour

• Intact temporary filling

d) THE APICAL EXTENT OF ROOT FILLING• It has significant influence on outcome• Flush root fillings have higher success

rates than short or long root fillings

SHORT

>2 mm short of the radiographic apex

FLUSH

0 – 2 mm within theRadiographic apex

LONG

Extruded beyondRadiographic apex

i. Overfilling and Overextension• Overfilling- “total

obturation of root canal space with excess material extruding beyond the apical foramen”

• Overextension- “extrusion of filling material beyond the apical foramen but canals have not been adequately filled and the apex has not been sealed”

ii. Underfilling

• Underfill results when both preparation and obturation are short of the desired working length or when obturation does not extend to the prepared length

Tooth seen here with an under-prepared and under-filled root canal treatment..

2. Root Canal Filling Materials

a) Ideal root canal filling material

1. Be easily introduced into root canal2. Seal the canal laterally & apically.3. Not shrink after being inserted.4. Impervious to moisture.5. Bacteriostatic, or at least not encourage bacterial growth.6. Be radiopaque.7. Not stain tooth structure. 8. Not irritate periapical tissues9. Be sterile, or atleast easy to sterilize10. Be easily removed from root canal if necessary.

c) Types

• Pastes

• Semisolid

• Solids

– Silver points

Gutta Percha

Resilon

ii. Semi Solids - GP with sealants

1. Cold GPa) Lateral compactionb) Variations to lateral compaction

i. Reverse cone techniqueii. Rolled cone technique

c) Single cone method

2. Canal warmed GPa) Vertical compactionb) System Bc) Thermomechanical compaction

3. Thermoplasticized GPa) Obtura IIb) Thermafil

• Gutta flow

1. Cold GP- a) Lateral Compaction

b.Variations i) Reverse cone technique

• Butt end of GP is inserted to achieve tug-back

ii) Rolled-cone technique

• Tailor made roll used for BlunderBuss canals.(canal is wider at the apex than cervical)

• Fusing multiple cones together butt to tip

• Softened with heat

• Rolled & chilled

• If too large then can be flash heated

2.Canal warmed GP - a) Vertical compaction

• Schilder technique or warm GP technique

• Lateral & accessory canals

• Used with step back prep

• Master cone selection• Sealer application• Cement master cone • Coronal end of cone cut

off

• Heated plugger forced into coronal 3rd- gets seared off

• Vertical condenser inserted, vertical pressure applied to force it apically

• Steps repeated until all accessory canals and lumen filled

• Remaining portion of canal plugged with warm sections of GP

b) System B – “continuous wave of condensation” (Buchanan)

• Employs thermostatically controlled heat source, softens GP in apical 4-5 mm with one application of heat

• Application of sealer• Insertion of master cone and heat

application from pre-selected tip, that delivers heat to apical 1/3rd

• Heat turned off before reaching predetermined length and forces last few mm in cooled state

• Cold plugger vertically compacts the remaining cooling GP

c) Thermomechanical compaction

• Compactor in form of reverse H-file at 8000 rpm inserted with light force parallel to master GP

• Rotating compactor heats and condenses GP & withdrawn while still rotating

• Disadv- non-uniform heating results in spiral-shaped sections of condensation

3.Thermoplasticized GP – a) Obtura II-Warm Gutta Percha

System• GP pellets are inserted into heated delivery system.

• Heated to approx 185-200°C

• Needle or applicator tip designed to deliver softened GP is introduced into canal to junction of middle and apical 3rd

• With needle in its position GP is passively injected into canal

• In 2-5 sec the softened GP fills apical segment & begins to lift the needle out of tooth

• Controlled compaction with prefitted pluggers adapt GP

• Additional amounts of GP can be easily injected

b) Thermafil Obturation

• Use standardized plastic points coated with α- GP.

• GP softened by heating & then canal can be obturated in 1 step.

• Special oven for warming• Canal evaluation with

uncoated carrier• Sealer applied, point

heated, inserted & carrier cut.

• Radiograph to confirm

Gutta flow

• Non heated flowable obturation material• Combines GP in powdered form (with particle size 30µm) and sealer

Gutta Flow

• Technique: 1. Gutta flow is layered into

apical part with final canal tip

2.3.4. Master GP is wetted with Gutta Flow and placed in the canals one by one.

5. Backfill with Gutta Flow 6. Excess GP points cut with

hot instrument 7. Completed obturation

3. Gutta percha removal

Various techniques

1. Rotary removal2. Ultrasonic removal3. Heat removal4. Heat and instrument removal5. File and chemical removal6. Paper point and chemical removal

1. Rotary removal

• Nickel Titanium files (0.04 & 0.06) tapered rotary – most effective

• Should be used with caution in underprepared canals

• Should accept passively• Divide the root into thirds

(1/3)• Speed 1200-1500 RPM

2.Ultrasonic removal

• Piezoelectric ultrasonic system for rapid elimination

• Produces heat that thermosoftens GP

• Specially designed instruments carried into canal

• Float GP coronally into pulp chamber, subsequently removed

3. Heat removal• Suitable for larger

canals due to larger cross-sectional diameter.

• Activate to red-hot, plunge to coronal most aspect of GP

• De-activate carrier- freeze a bite of GP

• Withdraw instrument - Bite removed

4. Heat and Instrument removal

• Employs heat and hedstrom files.

• Hot instrument plunged into GP to heat soften.

• 35,40 or 45 H-file quickly but gently screwed into softened mass.

• Poorly obturated canals – in 1 motion also.

• Especially good when GP extends beyond foramen.

5.File and Chemical removal

• Best option for small and curved canals• Chloroform – fill pulp chamber with solvent

– Select appropriate size K-file– Pick into chemically softened GP (creates pilot

hole.– Initially size 10 and then serial use of larger files– Continued till no GP particles on flutes of file.– Initially coronal 1/3rd followed by middle and then

apical 1/3rd (prevents apical extrusion)

6. Paper point and Chemical removal

• Wicking- drying solvent filled canals with paper point

• Essential in removing residual gutta percha

• Canal is first flushed with chloroform, solution is then absorbed & removed with PP.

• Once the PP are clean chloroform is flushed and aspirated repeatedly – creates back and forth turbulence

• Liberally flushed with 70% isopropyl alcohol and wicked to remove the residual GP.

ComparisonProtaper Hand Files SS Files

• Fewer instruments needed for preparation • The canal can be prepared

with moderate speed • ProTaper design increases

cutting efficiency • Canal curvature is well

maintained

• Consistent tapered preparation coronal to apical with minimal foramen enlargement

• Many instruments are needed for preparation

• Preparation is slow

• Cutting efficiency poor due to poor design

• Transportation is very common

• Tapered preparation always inconsistent with over enlargement apically highly probable

ComparisonProtaper Hand Files SS Files

• Less debris is extruded apically

• Can be used in abrupt curvature with prebent instrument WHEN pathway established by hand SS files

• Instrument separation is low

due to good tactile feedback

• Debris extrusion apically is high

• Can be used in abrupt curvature but final preparation never smooth

• Instrument separation has not been a historic problem

Coronal Flaring

• What if the coronal part is already big ?

• Which tooth ?– Anterior central incisors– Canines– Premolars (lower 1st and upper

2nd)