Slide 1 Endodontic Insrument

INTRODUCTION TO ENDODONTICS

ENDODONTIC INSRUMENTS Dr. Muna Marashdeh

MSc. Endodontics

What is Endodontics?

Endodontics is the specialty of dentistry that manages the prevention, diagnosis, and treatment of the dental pulp and the periradicular tissues that surround the root of the tooth.

"Endo" is the Greek word ="inside” "odont" is Greek ="tooth"

Endodontic treatment =treats the inside of the tooth

The pulp• Inside the tooth,

under enamel and dentin, is a soft tissue called the pulp

• Extends from the crown of the tooth to the tip of the roots where it connects to the tissues surrounding the root

• Contains blood vessels,nervesconnective tissue

• Creates the surrounding hard tissues of the tooth during development

• The pulp is important during a tooth’s growth and development

• Once a tooth is fully mature it can survive without the pulp, because the tooth continues to be nourished by the tissues surrounding it

Objectives of Endodontic Treatment

Relief of pain = symptom free To render the affected tooth biologically

acceptable and functioning without a diagnosable pathosis

Removal of pulp from root(s) of tooth Disinfections of root and surrounding

bone Root canal treatment is an attempt to

retain a tooth which may otherwise require extraction.

Indications for Endodontic Therapy

1. Teeth with pulpal and /or priapical pathosis. 2. Teeth with no pulpal or periapical pathosis

may need endodontic treatment due to: The need for post and core construction to

rebuild the missing coronal portion of the tooth Traumatic pulp exposure due

to dental work or accidental fracture. Esthetic requirement

Contraindications for Endodontic Therapy

1-Teeth with insufficient periodontal support. 2-Teeth with vertical root fracture.4-Non restorable teeth which can not properly function after endodontic treatment.5-Non strategic teeth which can not serve in occlusion or as abutments after endodontic treatment

Phases of Endodontics treatment

Diagnostic phase

Preparatory phase (cleaning & shaping)

Obturation phase

Diagnostic phase

During this phase the condition of the tooth is determined and the plan of treatment is developed

Examination A kit for examination and diagnosis

includes (1) a front surface mouth mirror; (2) a periodontal probe; (3) an explorer, such as the double-ended No. 5 explorer; (4) spoon excavator ; (5)the Glick No. 1 instrument; and (6) cotton forceps.

Endodontic Explorer

Explorers are double-ended instruments with long tapered tines at either a right or an obtuse angle. This design facilitates the location of canal orifices. They are very stiff and should not be inserted into canals or used for condensing gutta-percha.

Explorers should never be heated.

Spoon ExcavatorThe spoon excavator is a long-shank instrument. The excavator is used to remove caries, deep temporary cement,or coronal pulp tissue. The endodontic excavator has a right or left orientation similar to that of operative hand excavators.Excavators should not be heated.

Glick No. 1 instrument

The Glick No. 1 instrument is used for placement of temporary restorations with the paddle end and removal (and then condensation) of excess gutta-percha with the heated plugger end.

The rod-shaped plugger is graduated in 5-mm increments.

Preparatory Phase(Cleaning & Shaping)

During this phase the condition of the tooth is determined and the plan of treatment is developed.

Instruments used for access and cleaning and shaping include (1)hand pieces (slow and high speed),(2) burs, (3)rubber dam, (4) a 5- to 6-ml Luer-Lok syringe with a 27-gauge needle, (5)locking cotton pliers, (6) rotary instruments (Gates-Glidden drills), (7) a plastic instrument (Glick No. 1) for temporary placement, (8) broaches and files, (9) a lentulo spiral drill, and (10) a millimeter rule.

Rubber Dam

Rubber dam over the area to isolate the tooth, keep it clean and free of saliva during the dental procedure

Irrigation Syringe

Nomenclature for Instruments

The nomenclature follows the recommendations of the International Organization for Standardization (ISO):

1. Hand-operated include K-type reamers and files, broaches, and Hedstrom-type files.

2. Engine-driven are hand types that have a latch that inserts into a slow-speed handpiece. These include rotary (Gates- Glidden and Peeso) engine-driven reamers and files and reciprocating files or reamers.

3. Ultrasonic and sonic are diverse in design.

4. Nickel-titanium is a cross-over design and has been adapted both for hand instruments and rotary applications.

PHYSICAL CHARACTERISTICS

To debride a region of the canal space completely, the instrument must contact and plane all walls.

Despite continual improvements in design and physical properties, there are still no instruments that totally clean and shape all root canal spaces.

Stainless steel instruments are relatively inflexible, which renders them not particularly adaptable to canal curvatures.

Nickel-titanium instruments are more flexible and adapt more readily to fine, curved canals but have no advantage over stainless steel files in irregular canal spaces.

Instrument Fabrication

A hand-operated reamer or file begins as a round wire that is modified to form a tapered instrument with cutting edges.

The instrument is used with a twisting (reaming) or pulling (filing) motion in an attempt to produce clean, smooth, symmetrical canal walls.

Hand-Operated Instruments

Several cross-sectional shapes of files are commercially available .

Longitudinal and cross-sectional shapes of various hand-operated instruments. (Those marked with an asterisk are brand names.)

Note that small sizes of K-reamers, K-files, and K-Flex* have a different shape than the larger sizes

Two techniques for manufacturing these instruments have been developed

Machined Ground Twisted

Machined One technique involves machining

(grinding) the instrument directly on a lathe; an example is the Hedstrom-type file, All nickel-titanium instruments are machined

Some manufacturers produce K-type files using the machined (lathe-grinding) process .

This change from the grinding and twisting manufacturing process results in different physical and working properties from the original K-type file

For instance, the machined file has less rotational resistance to breakage than a ground-twisted file of the same size.

Hedstrom file, machined by rotating a wire on a lathe. Note the spiral shape. These are efficient cutters (on the pull stroke) but are more susceptible to separation when locked and twisted. B and C, A machined K-type file. Note that the transition angle at the leading cutting edge of the tip is rounded, rendering it noncutting

Ground-Twisted Another technique consists of first grinding, then

twisting. Raw wire is ground into tapered geometric blanks: square, triangular, and rhomboid.

The blanks are then twisted counterclockwise to produce helical cutting edges. These are K-type files and reamers.

K-type files have more twists per millimeter of length than the corresponding size of K-type reamer.

Both have a pyramidal tip (75 ± 15 degrees) that is produced by grinding after twisting.

Ground-twisted instruments. A, A square file blank ground from wire. After twisting counterclockwise, the appearance of a file (more flutes) (B) and reamer (fewer flutes) (C).

Standardization

Lengths Files and reamers are available in three shaft

lengths: 21, 25, and 31 mm. Shorter instruments afford improved operator control and easier access to posterior teeth, to which limited opening impairs access. The 25- and 31-mm instruments are used for longer roots. The 25-mm instruments are the most commonly used instruments during root canal preparation.

Sizing Dimensions of K-type files and reamers are designated according to the

diameters of the instrument at specified positions along its length (as stated in ADA specification No. 28)

File tip diameters increase in 0.05-mm increments up to the size 60 file (0.60 mm at the tip), and then by 0.10-mm increments up to size 140.

The diameter at the tip of the point is known as D0. The spiral cutting edge of the instrument must be at least 16 mm long, and the diameter at this point is D16.

The file diameter increases at a rate of 0.02 mm per running millimeter of length

The nickel-titanium rotary instruments have other variable tapers of 0.04 and 0.06. For every millimeter of length, these greater tapers make these more aggressive in creating marked flaring preparation

Tip Design Originally, the tip angle of K-type files and reamers

was approximately 75 degrees plus or minus 15 degrees This design was intended to provide cutting

efficiency without an excessively sharp transition angle. Newer designs have different tip angles and designs

in an attempt to minimize canal alterations. Some machined K-files incorporate a so-called

nonaggressive tip or noncutting tip to provide less dentin cutting by reducing the sharp tip transition angle.

Torsional Limits Torsional limit is the amount of rotational torque that can be

applied to a “locked” instrument to the point of breakage (separation).

Smaller steel hand-preparation instruments (less than size 20) can withstand more rotations without breaking than

larger (greater than size 40) instruments. Machined K-type files have different physical and

working properties than ground-twisted files. Machined files are weaker, demonstrating less plastic deformation before failure occurs.Therefore this tendency toward less visible deformation before separation requires more caution with the use of machined files to avoid

instrument failure.

Color Coding Color coding of file handles designates size. Color coding

of the newer nontraditional instruments varies according

to the manufacturer.

Broaches

Barbed broaches are stainless steel instruments with plastic handles. The tapered-wire broach is barbed by scoring and prying a tag of metal away from the long axis of the wire.

Barbs entangle and remove canal contents. This instrument should be neither bound in the canal nor aggressively forced around a canal curvature. Either action may cause the barbs to engage the canal wall, preventing the broach from being removed intact or fracturing.

Barbed broaches should not be reused. Single-barbed broaches are available in

presterilized bubble packaging.

Lentulo Spiral Drills

Lentulo spiral drills are twisted wire instruments used in the slow-speed handpiece .

They have been used to spin pastes, sealer, cements, or calcium hydroxide into the canal. They must be used with care to avoid “throwing” quantities of unset material out of the apex.

The drill must be rotated so that it will not “screw” itself into the canal; it may lock and separate.

Engine-Driven Instruments

Rotary Instruments Some preparation techniques require slow-speed rotary

instruments to facilitate preparation, primarily in establishing straight-line access, the most common are Gates-Glidden drills and Peeso reamers

. Table shows the comparative ISO sizes of both Gates-Gliddendrills and Peeso reamers.

Size Gates-Glidden Drills

Peeso Reamers

No. 1 0.4 mm 0.7 mm

No. 2 0.6 mm 0.9 mm

No. 3 0.8 mm 1.1 mm

No. 4 1.0 mm 1.3 mm

No. 5 1.2 mm 1.5 mm

No. 6 1.4 mm 1.7 mm

Gates-Glidden Drills Gates-Glidden drills are elliptically (flame) shaped burs with a latch

attachment. Gates-Glidden drills are used to open the orifice. They also achieve

straight-line access by removing the dentin shelf and rapidly flaring the coronal and middle third of the canal.

Gates-Glidden drills are designed to break high in the shank region. This design allows easier removal of the broken instrument from a tooth; fracture near the cutting head may block a canal

Importantly, these drills must be continuously rotated. If they stop, the head may lock in the canal, with torsional failure and fracture.

Gates-Glidden drills are available in 15- and 19-mm lengths. The shorter instruments are helpful in posterior teeth,

where access to the canal orifice is limited.

Peeso Reamers Peeso reamers are also used as adjunctive devices

in canal preparation. They are basically similar to Gates-Glidden drills but have parallel cutting sides rather than an elliptical shape. These instruments are available with or without safe tips.

Peeso reamers have been suggested as a means of improving straight-line access, although they are less flexible and less well controlled than Gates-Glidden drills. Both types are aggressive and can rapidly

over enlarge the canal.

Engine-Driven Nickel-Titanium Files Engine-driven nickel-titanium files allow

greater control in small, curved canals. These instruments do not have a cutting end and have less tendency to transport the apical preparation. The files are available in a variety of shapes and designs

INTRACANAL USAGE

Broaches Removal of pulp requires a broach that will

not bind and yet is large enough to ensnare the tissue. Binding should be minimized because of possible breakage.

Reamers and Files Two types of motion are common in root

canal preparation: reaming and filing Reaming consists of rotating the

instrument clockwise and scribing an arc from one cutting edge to the next.

Filing requires a series of repetitive motions. First, the instrument is advanced to its full length into the

canal space using a passive “twiddling” (teasing without planing) motion.

Next, the file is rotated (a quarter turn or more) and then withdrawn from the canal space while the tip is pushed firmly against a canal wall, much as a paintbrush is applied to a wall when painting.

The twiddling, reaming, and withdrawal motions are repeated with the file tip pushed against a different portion of the canal wall on each outstroke until all walls have been planed (circumferential filing).

Hedstrom-type files and files with a similar design ( S& U) are used only with a filing motion because they have less torsional resistance to breakage.

Avoidance of Instrument Separation

Separation of hand files in the canal is prevented by regularly inspecting the instrument for defects such as

(1) unwinding of the flutes (twisting clockwise and opening of the flutes),

(2) roll-up of the flutes (excessive continued clockwise twisting after unwinding),

(3) tip distortion (the tip has been bent excessively)

(4) corrosion. If an instrument exhibits any

signs of wear, it should be discarded immediately. Prevention is the key to avoiding untimely instrument separation.

Rotary Instruments All of the engine-driven nickel-titanium files rely on

rotational motion only and therefore have a reaming action.

Avoidance of Instrument Separation The number of canals that can be prepared with a

nickeltitanium instrument varies from 4 to 16, depending on the size and curvature of the canals and pressure used with the files. When the canal is smaller and more curved, there is more wear and tear on the instrument.

All manufacturers suggest discarding the files if any deformation occurs. Studies have suggested that lower speeds reduce the likelihood of instrument fracture

Obturation phase

During this phase the root canals are filled with an inert material to achieve a hermetic seal as close as possible to the anatomic apex.

Instruments and materials used for obturation include (1)Gutta percha (2)Paper points (3)Root canal sealer (4)spreaders or pluggers, (5) Glick No. 1 for heat transfer and temporary placement, (6) locking cotton pliers, and (7) 5/7 plugger or pluggers used for vertical condensation.

Several filling techniques are available. The two most practiced techniques are , lateral and vertical condensation.

Gutta Percha

Paper Points

Root Canal Sealer

Lateral Condensation The instruments used for lateral condensation are

spreaders and small pluggers . They are used for condensing and adapting gutta-

percha and creating space for accessory cones. They are either handled, with a shank attached to a metal handle, or finger-type, with only a plastic handle .

The handled instruments are stiff because they are generally made of annealed stainless steel. Finger spreaders and pluggers are not annealed and therefore are dead soft, giving them more flexibility. Handled instruments do not negotiate curved canals. Finger spreaders and pluggers are best suited for obturating curved canals.

Finger spreaders and pluggers have different tips. Pluggers are flat, whereas spreaders are pointed. Finger spreaders and pluggers behave similarly and

are used interchangeably in lateral condensation. Both stainless steel and nickel-titanium spreaders

are available. The obvious advantage of nickel-titanium spreaders

overstainless steel spreaders is greater spreader

penetration in highly curved canals.

Vertical Condensation In this obturation technique the filling material is

alternately softened (with heat) and then vertically compacted with pluggers.

The softened gutta-percha filling material is pushed into the interstices of the canal, but this technique offers less apical control of the material than lateral condensation.

Vertical condensation instruments can be divided into two categories: those that are heated to transfer heat to the guttapercha and those that condense the gutta-percha

Obturation Phase

STERILIZATION AND DISINFECTION Endodontic instruments are contaminated with blood, soft

and hard tissue remnants, and bacteria and bacterial byproducts.

Thus they must be cleaned often and disinfected during the procedure and then sterilized. Also, because the instruments may be contaminated when new, they must be sterilized before initial use.

Different sterilization techniques are available. Small kits, such as those used for examination, may

conveniently be bagged, sterilized, and stored in the package until needed.

Larger kits for treatment may be more rapidly and easily handled in cassettes for sterilization and storage

THANK YOU

Central , lateral, canine.( upper, lower) Premolars, molars ( upper, lower)