Proerties and uses of MTA

Properties

Ø  ph initial 10.2 & rises to 12.5 when set

Ø  Highly alkaline

Ø  Setting Time is 2 hrs 45min

Ø  Compressive strength 40 mpa immediately

   & 70 mpa after 21days

Ø  MTA has calcium oxide which reacts with water to form calcium hydroxide

Ø  This causes formation of calcite crystals & & fibronectin

Ø  These act as initiating step for hard tissue barrier formation

Ø  Fibronectin promotes cellular adhesion & differentiation

Uses

Ø  Repair of perforation

Ø  Root end filling material

Ø  Pulp capping agent

Ø  Apexification

Ø  Apical third filling material

Ø  Obturating material 

Advances in material aspect MTA

Advances in material aspect

MTA

Ø  Mineral Trioxide Aggregate

Ø  Developed at Loma Linda University

Ø  By Dr. Mohammed Torabinejad

Ø  Initially developed as perforation repair & root end filling material .

Ø  Now finds wide application in endodontics

Material is
FDA approved & commercially available as
Pro Root MTA

Composition

Ø  Main molecules are calcium & phosphorous ions

Ø  Derived from components

   --tricalcium silicate ,

   --tricalcium aluminate ,

   --tricalcium oxide &

   --silicate oxide

Ø    Bismuth oxide imparts radio-opacity

Portland cements & MTA

Ø  Portland cements contain the same components as MTA except that MTA also contains bismuth oxide for radio-opacity 

APICAL THIRD FILLING , Calcium Hydroxide Apical Filling

APICAL THIRD FILLING

                                                               SimpliFill Obturation

Calcium Hydroxide Apical Filling.

Ø  Mainly used where the apexification is desired

Ø  It is thought to provoke the cementogenesis

Calcium-Phosphate Cement Obturation.

Ø  More recently, Harbert has suggested using tricalcium phosphate as an apical plug,much like dentin shavings and calcium hydroxide have been used

Ø  In testing the sealing ability of CPC when used as a root canal sealer-filler, the Paffenbarger group reported that in most of the specimens there was “no dye penetration into the filler-canal wall interface”

Ø  Two calcium phosphate compounds, one acidic and one basic, are unique in that when mixed with water they set into a hardened mass”—hydroxyapatite—the principal mineral in teeth and bones

Ø  Another possibility of using hydroxyapatite relates to the laser. A cross-linked collagen-hydroxyapatite mixture has been placed in the root canal and “melted” to place with a laser beam through a fiber optic.

Ø  Another possibility of using hydroxyapatite relates to the laser. A cross-linked collagen-hydroxyapatite mixture has been placed in the root canal and “melted” to place with a laser beam through a fiber optic.

Thermoplasticized Injectable Gutta-percha Obturation

Thermoplasticized Injectable Gutta-percha Obturation

SOLID-CORE CARRIER: MANUAL INSERTION THERMAFIL

Advances in Obturation - Thermomechanical Solid-Core Gutta-percha Obturation

Advances in Obturation

Thermomechanical Solid-Core Gutta-percha Obturation

Ø  This system consists of titanium core devices that come in ISO sizes 15 to 60, resemble latch-type endodontic drills, coated with alpha-phase gutta-percha

Ø  These devices are fitted to the prepared root canal and then, following the sealer, are spun in the canal with a regular low-speed, latch-type handpiece.

Ø  Friction heat plasticizes the gutta-percha and it is compacted to place by the design of the Quick-Fill core.

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Newer irrigating solutions And lasers

Newer irrigating solutions

Ø  Salvizol

Ø  Tublicid

Ø  BDA ( Bis-dequalinium acetate) Solvidont

Ø  Ozonized water

Ø  Endo Dilator N 

Ø  Electro chemically activated water

Ø  MTAD

Lasers are mainly used in Preparatory Phase of Endodontics for disinfecting the root canal and biomechanical preparation

Lightspeed and quantec files

LIGHTSPEED FILE

Ø  Resembles a Gates-Glidden drill  

Ø  Used in apical curvatures where rotary instruments may be in jeopardy.

Ø  Speed: 1,300 to 2,000 rpm 

Ø  The instruments come in ISO sizes beginning with No. 20  to 140.

Ø  Advantages: the ability to finish the apical-third preparation 

QUANTEC FILES

•          Although called a “file,” is more like a reamer—a drill.

•          Produced in three different tapers—0.02, 0.04, and 0.06.

•          Quantec flare series — 0.08, 0.10,& 0.12 taper for coronal 1/3^rd.

•          The radial lands of the Quantec are slightly relieved to reduce frictional contact with the canal wall, and the helix angle is configured to efficiently remove debris.

Engima to Endodontist

Engima to Endodontist

Bifurcationss & Trifurcations are most common in mandibular first premolar .They present a challenge during cleaning , shaping  and obturation .Because of this it is known as "Engima to Endodontist"

RaCe , Protaper files , K3 files

RaCe

Ø  Heraeus Kulzer introduced this new system

Ø  RaCe {Reamers with alternate cutting edge}.

Ø  Available in  2% , 4% , 6% , 8%  or 10% taper.

Ø  Non cutting tip for guidance.

Ø  The triangular cross section and alternative cutting edges ensures efficient evaluation of chips and cutting debris.

ProTaper  FILES

• Consist of -

I.   3 shaping files: SX, S1 & S2.

II.  3 finishing files: F1, F2&F3

• Available in 21 & 25mm lengths
• Used with utilized in gear reduction, high torque, electric hand pieces at speeds ranging from 250 to 300 rpm.
• Convex triangular cross section

K3  FILES

Ø  Available in two tapers:

1. 0.04 – green colour
2. 0.06 – orange colour

Ø  Advantages 

1.  Safe ended tip.

2.  Positive rake angle:

l  Slight positive cutting angle – cutting

l  Profiles, other conventional – negative angle – scraping.

3.  Wide radial angle provides more mass at core so less chances of fracture.

4.  Access handle:

l  Short handle for better access in posterior teeth.

5.  Simplified colour coding        

ULTRASONIC and profile

ULTRASONIC

Ø  Oscillating - side to side movement.

Ø  Vibrations above the audible range of perception.

Ø  Vibrations at very high level: 20 – 25kHz.

Ø  produces vibratory movements then transferred to the instrument.

PROFILE

0.06 PROFILE:

Ø  Taper 6% , No  15 to 40 , lengths 21 mm and 25 mm .

0.04 PROFILE:

Ø  Taper 4%, No 15 to 40, lengths 21mm, 25mm and 31mm. 

Ø  Designed for continuous rotation at 150-350 rpm in a contra angle hand piece

Ø  A modified tip without transition angle does not cut but guides the file. 

Advances in Engine Driven Instruments

Advances in Engine Driven Instruments

GATES GLIDDEN DRILL

Ø  Long thin shaft, ending in a flame shaped head which cuts only laterally.

Ø  A safe tip guard to prevent perforation.

Ø  Used with slight apically directed pressure & pulled back.

Ø  If it get binds into dentin, fracture occurs at narrowest diameter i.e. at neck near the hand piece. So ease in retrieval from canal.

Ø  Speed: 750 to 1000rpm.

FLEXO GATES

Ø  Hand instrument designated for apical preparation.

Ø  A smooth flexible shank which is circular and small in cross section.

Ø  Weak at the handle of the thin shank to ensure access for the removal of broken instrument.

PEESO REAMER

•          Long, sharp flute connected to thick shaft.

•          Non cutting tip

•          Cuts only laterally

•          Large rake angle than GG.

Indication:

                To prepare post space in the obturated canal.

Advances in Hand instruments

Advances in Hand instruments

TRIPLE FLEX FILE

•          A hybrid instrument.

•          More flutes than reamer but fewer than K-file.

•          Made from triangular stainless steel blank by twisting, not ground.

•          More aggressive & flexible than regular K-style instrument.

UNIFILE

•          Introduced by McSpadden as modification of H- file.

•          Cross section shows double helix or ‘S’ shape.

•          Flutes are less deeper than  H-file, so greater bulk so less likely to fracture.

•          Cutting of dentin is more efficient in withdrawal strokes.

•          S-file is modification of unifile with less fragility.

HELIFILE

•          Modification of H-file.

•           Method of manufacture is similar to H-file.

•          Cross section has three blades.

•          Advantage:

•          more space for removal of dentinal chips & debris.

SAFETY H – FILE

Ø  Modification of H-File done by Buchanan.

Ø  Non cutting tip to prevent ledging into curved canals.

Ø  Smooth edges on one side of file to prevent unnecessary dentin removal in curved canals.

U – FILE

Ø  Developed by Heath (1988).

Ø  Cross-sectional configuration has two 90-degree cutting edges at each of the three points of the blade.

Ø  Advantages:

1.  The flat cutting surfaces act as a planing instrument.
2. Aggressively planes the external convex wall while avoiding the more dangerous internal concave wall.
3. Has a non cutting tip.

advocated techniques other than conventional for Biomechanical preparation

Various advocated techniques other than conventional for Biomechanical preparation are   

STEP BACK  PREPARATION

Principle

Ø  This technique includes the use of larger root canal instruments sequentially and each set 1 mm shorter than the preceding instrument, once the canal has been enlarged in the apical 1/3rd to at least #25 or #30 instrument.

HYBRID TECHNIQUE

It was advocated by Georig and Buchanan. It is a combination of step back and step down hence called as Hybrid technique.

BALANCED FORCE TECHNIQUE

Ø  It is derived from the concept that for every action there is an equal and opposite reaction.

Ø  At this point the balanced force instrumentation begins. It is simply an expansion of the concept of reaming the canals which differs primarily in that the cutting motion is intentionally counter clockwise and accomplished at any level without blockage.

Electronic Apex Locators - Third generation

Electronic Apex Locators

Third generation

High Frequency

 Examples:

Ø  Endocator

Ø  Endex

Ø  Apex finder A F A

Ø  Justy two

Ø  Root ZX

Able to make correct measurement in the presence of conductive fluids with specially coated file

ENDEX

APEX FINDER A F A(All Fluids Allowed)

Root ZX

Electronic Apex Locators

WORKING LENGTH ESTIMATION

Electronic Apex Locators

Ø  These devices attempt to locate the apical constriction, the cemento dentinal junction or the apical foramen.

Electronic Apex Locators

History:

The Resistance Method (first generation)

Sunada (1962)

Root Canal Meter (1969)

Impedance of the canal (second generation)

Inoue (1971)

Examples

Ø  Neosono

Ø  Pio

Ø  Apex finder

Ø  Endo analyser

Advances in Preparatory Phase

Advances in Preparatory Phase

                                The biological objective for cleaning and shaping are to "free" the root canal system from pulp, bacteria and their toxins. The mechanical objectives   are to carve away restrictive dentine for obturation in three dimensions

                                Due to the understanding of the various types of coronal curvature and to avoid any complications  the ever diligent researcher has been constantly working not only to develop new instruments but also newer techniques.

The use of Surgical operating microscope has not only contributed to understanding of the complex root Anatomy but also has made the Endodontic Procedures more precise and Perfect

Today finding four canals in a mandibular or maxillary molar does not take anybody by surprise

Dual wavelength spectrophotometry

Dual wavelength spectrophotometry

Ø  This method measures oxygenation changes in capillary bed rather than in supply vessels & hence is independent of pulsatile flow.

Ø  It is useful in pulp tissue as there are arterioles rather than arteries in pulp ,encapsulated in firm dentin , making it difficult to detect pulse in pulp space.

Ø  DWLS detects the presence or absence of oxygenayed blood at 760 & 850nm  

LASER DOPPLER FLOWMETRY

LASER DOPPLER FLOWMETRY

Ø  Non invasive , electro optical technique , allows for semiquantitative recording for blood flow

Ø  Incident laser beam of known wavelength is directed through crown of tooth  and Moving red blood cells cause frequency of laser beam to be shifted & some light to be back scattered out of tooth

Ø  Reflected light is detected by photocell on tooth surface the output of which is proportional to the number & velocity on moving red blood cells

Pulse oximetry

Pulse oximetry :-

•          Non invasive – oxygen saturation monitoring device widely used in medical practice.

•          In the red range the oxyhaemoglobin absorbs less light than deoxyhaemoglobin  & vice –versa in the infrared region.

•          System consists of a probe containing a diode that emits light in two wavelengths

•          Red –660nm

•          Infrared –850nm

•          Probe is placed on labial surface of tooth-ideally on middle 1/3rd & photodetector diode is placed on opposing surfaces of tooth.