Endodontics

Root Canals Obturation Materials

Dr . Rasha Al_Shamaa

Introducton

It is essential ,That endodontic therapy must iclude sealing of the root canal system to prevent tissue fluides from percolating in the root canal and prevent toxic by _ product from both necrotic tissue and micro_organism regressing onto peri_radicular tissue.

Introducton

The current Accepted methods of obturation of prepared canals employs a solid and semisolid core such as gutta-percha and root canal sealer.

A Root Canals can be Obturated when

No pain, swelling, tenderness to percussion, No fistulation associated with the tooth
The instrumented canal is dry and free of odor( no exudates or purulent discharge into the canal
If the pulp is necrotic or a per apical lesion is present, the root canal cannot be filled before the second appointment
Teeth associated with procedural accident, perforation must not be filled until another treatment

Requirements for an ideal root filling materials

It should be easily introduced into the canal.
It should seal the canal laterally as well as apically.
It should not shrink after being inserted.
It should be resistant to moisture.
It should be bacterio static or at least not encourage bacterial growth


Requirements for an ideal root filling materials
It should be radiopaque.
It should not stain tooth structure.
It should not irritate periapical tissue.
It should be sterile, or quickly and easily sterilized before insertion.
It should be easily removed from the root canal if necessary

Types of root canal filling materials

A_ Sealer cements.
1 -Zinc oxide- eugenol cements with various additives.
2 -Epoxy resins (AH-26).
B. Semisolid materials e.g. gutta-percha.
C. Solid materials e.g. silver points, Titanium points.
D. Resin-based core filling materials e.g. Resilon

Sealer cements

The sealers are responsible for the principal functions of the final root filling: sealing off of the root canal system, entombment of remaining bacteria and the filling of irregularities in the prepared canal

Types of Root Canals sealer

Zinc oxide eugenol.
Calcium hydroxide.
Glass- ionomer.
Meth acrylate -based resin sealers e.g. Endo REZ, Real Seal, AH26, AH-Plus.
Silicone e.g. Lee Endo Fill


Requirements for an ideal root filling Sealer
1. Have good adhesion to the canal wall.
2. Have sufficient setting time, giving the clinician sufficient time to make necessary adjustments to the filling material.
3. Be capable of producing a hermetic seal.
4. Have very fine powder particles that mix easily with the cement liquid.

Requirements for an ideal root filling Sealer

5. Be radio paque, often revealing the existence of accessory canals, multiple foramina, resorpative areas, fracture lines, and other unusual morphologic characteristics.
6. Expand while setting.
7. Be bacterio static.
8. Be biologically acceptable; not irritate peri apical tissues.
9. Be soluble in common solvents if removal becomes necessary

Meth acrylate-based resin sealers

MBRS are new in endodontics and are derived from polymer chemistry technology initially developed for adhesive restorative dentistry; EndoREZ (ER) is a hydrophilic, two-component (base and catalysts), dual-curing self priming sealer. The sealer can be used with gutta-percha or with resin-coated gutta-percha cones, the latter with the objective of establishing continuous adhesion (uni block or mono bloc) between all materials

Semisolid materials e.g. gutta-percha

Crystalline gutta-percha may occur in α- or β-phase. There are only minor differences in chemical behavior and physical properties between the two. The α phase appears in nature; the β -phase occurs during refining and is dominant in the products used in endodontics

Semisolid materials e.g. gutta-percha

Gutta-percha points consist of some 20 percent gutta-percha and up to 80 percent zinc oxide. A dye and metal salts are added for color and radiographic contrast. Some manufacturers add antimicrobials, e.g. calcium hydroxide, chlorhexidine or iodoform, to report some disinfectant properties to the materials

Advantages

Long history of use.
Biocompatibility.
Flexibility of technique.
Thermoplastic.
Compatibility with sealers.
Easily removed.
Inexpensive.
Radio paque.
Minimal toxicity.
Dimensional stability

Disadvantages

Provides no seal.
Inability to bond to dentin.
Inability to bond to sealers.
Shrinks upon cooling.
Potential for voids.
Lack of rigidity.
Easley distorted by pressure


Solid materials e.g. silver points
Introduced by Jasper in 1940, These points are made from silver, They have the advantage of being rigid; therefore they are used in very narrow and severely curved canals. The main disadvantages are that silver cones are round in cross section

Solid materials e.g. silver points

therefore they cannot be used in oval cross sectioned canals, and silver cones may produce corrosion products which will be harmful to the periapical region which impede healing, also silver points not used with post, Silver points are also not indicated for filling anterior teeth, single canal premolars, or large single canals in molars

Resin-based core filling materials e.g. Resilon

It was claimed to overcome the limitations of gutta-percha and traditional resin-based restorative materials used in root canals. The material contained filler particles made of bioactive glass, bismuth oxychloride, and barium sulfate

Resin-based core filling materials e.g. Resilon

Resilon could bond to dentin by copolymerizing with resin cement via methacrylate-based components in its molecular structure. According to the manufacturer, Resilon has a melting range between 70 and 80oC, which is very similar to gutta-percha, and a filler content of more than 60% by weight. It could be softened with heat or solvents such as chloroform, and was highly radiopaque

Resin-based core filling materials e.g. Resilon

The dentin bonding system or sealer for Resilon is called Epiphany. The Epiphany primer, an aqueous self-etching primer, contains 2-hydroxyethylmethacrylate (HEMA), a sulfonic acid– terminated functional monomer, and a polymerization initiator


Resin-based core filling materials e.g. Resilon
Resilon cones and the Epiphany resin are said to form a ‘mono-block’, i.e. a single block of material that adheres to the dentinal wall

Mono block

Canals filled to the apical dentinocemental junction
They are filled to the anatomic limit of the canal

Thank You