Endodontic Obturation: Root Canal Sealing

Obturation

• The final stage of endodontic treatment involves filling the root canal system with non-irritating hermetic sealing agents
• Successful canal obturation depends on excellent endodontic cavity design, shaping, and cleaning
• Four key questions to understand this phase include: why, when, what, and how to obturate root canals

Objectives for Obturation (Why)

• Achieve total obliteration of the root canal space
• Prevents ingress of bacteria and body fluids, and egress of remaining bacteria
• Attain a fluid-tight seal to prevent bacterial leakage
• Replace the empty root canal space with an inert filling material
• Prevents recurrent infection
• Seal the root canal space and have a coronal seal up to cavo-surface margins
• Allows for long-term success of root canal therapy

Time for Obturation (When)

• Root canal(s) is cleaned and shaped to optimum size
• The tooth is asymptomatic (comfortable)
• There is an Absence of any sign of infection, foul odor, exudate (dry canal), and sinus tract

Obturation Completion

• Obturation can be completed in a single visit if irreversible pulpitis is present and the main source of pain (the pulp) is extirpated

Obturation Materials

• Many root canal filling materials have been advocated over the years
• Some have been rejected due to being impractical, irritational, or biologically unacceptable
• Acceptable filling materials are grouped into plastics, solids, cements, and pastes

Grossman's Ideal Properties of Root Canal Obturation Materials

• Material should be easy introduced in the canal
• Seals canal laterally and apically
• Dimensionally stable after being inserted
• Impervious to moisture
• Bacteriostatic or at least should not encourage bacterial growth
• Radiopaque
• Non-staining to the tooth structure
• Non-irritating
• Sterile and easily sterilized.
• Removed easily from the canal if required

Materials Used for Obturation

• Plastics: Gutta-percha & Resilon
• Solids or metal cores: Silver points, gold, stainless steel & titanium.
• Cements and pastes: Sealers, Hydron, MTA, calcium phosphate & Gutta flow.

Gutta Percha Chemical Nature

• Gutta percha name derived from GETAH (gum) and PERTJA (tree name)
• It is a dried coagulated extract from Brazilian trees

Gutta Percha Chemistry

• Natural chemical form is 1, 4-polyisoprene
• It is a trans isomer of natural rubber
• Has been used for coating trans-Atlantic cables and golf ball cores

Gutta Percha Phases

• Pure gutta-percha exists in two crystalline forms,Alpha and Beta
• These differ in molecular repeat distance and single bond form
• Natural gutta-percha from the tree is in alpha form while commercial products are in beta form
• These phases are inter-convertible

Alpha Form of Gutta Percha

• Pliable and tacky at 56°-64°C
• Runny and sticky with a lower viscosity
• Available as bars or pellets

Beta Form of Gutta Percha

• Rigid and solid at 42°-44°C
• Compactable and elongatible with a higher viscosity
• Used in manufacturing gutta-percha points and sticks

Gutta Percha Physical Nature

• Expands slightly on heating
• Condensation is recommended during heat techniques to compensate for cooling shrinkage
• Becomes brittle on aging due to oxidation
• Refrigeration extends shelf life
• Cannot be heat sterilized, use 5.25% sodium hypochlorite (NaOCl) for one minute, then rinse with hydrogen peroxide or ethyl alcohol to remove crystallized NaOCl

Gutta Percha Application

• Should always be used with sealer and cement to seal the root canal space as it lacks adhering qualities
• Soluble in solvents like chloroform, eucalyptus oil, and orange oil

Gutta Percha % Composition

• Gutta-percha 20%, functions as the matrix
• Zinc oxide 65%, functions as the filler
• Metal salts 10%, functions to increase radiopacity
• Waxes/resins 5%, functions to increase plasticity

Gutta Percha Availability

• Standard cones of the same size and shape as ISO endodontic instruments
• Auxiliary points are non-standardized cones
• Greater taper points are available in 4%, 6%, 8%, and 10% tapers
• Pellets/bars are used in thermoplasticized obturation techniques like the Obtura system
• Precoated core carriers: stainless steel, titanium, or plastic carriers precoated with alpha-phase gutta-percha like the Therma fill system
• Syringe systems use low viscosity gutta-percha powder like the Successful and Alpha seal systems
• Gutta flow is gutta-percha powder incorporated into silicone-based sealer
• Gutta-percha sealers like chloropercha and eucopercha are gutta dissoloved in chloroform or eucalyptolol for use in the canal

Gutta Percha Advantages

• Compactable and plastic, adapting to irregular canal contours
• Can be softened by heat or chemically
• Inert and tissue tolerant
• Dimensionally stable
• Radiopaque
• Can be easily removed from the canal when necessary

Gutta Percha Disadvantages

• Lacks rigidity
• Lacks adhesive quality, so does not adhere to canal walls
• Can be easily distorted, deforms by stretching
• Shrinkage on cooling

Medicated Gutta-Percha

• Calcium hydroxide-containing gutta-percha, Ca(OH)2 points, they made by combining - 58% of calcium hydroxide in a matrix of 42% gutta-percha
• Available in ISO size of 15-140
• Calcium hydroxide is activated by moisture in the canal
• Includes lodoform-containing and Chlorhexidine diacetate-containing gutta-percha as well

Resilon

• Synthetic resin-based polycaprolactone polymer to be used with Epiphany, a new resin sealer
• Used to attempt to form an adhesive bond at the interface of the synthetic polymer-based core material, the canal wall, and the sealer
• It is proposed that the bond to the canal wall and to the core material creates a “monoblock”
• Supplied in standardized ISO sizes and shapes while conforming to the configuration of nickel-titanium rotary instruments
• Available in pellet form for injection devices
• The manufacturer states that handling properties are similar to those of gutta-percha
• Can be used with any obturation technique
• It contains polymers of polyester, bioactive glass, and radiopaque fillers (bismuth oxychloride and barium sulfate) with a filler content of approximately 65%
• It can be softened with heat or dissolved with solvents
• A resin-based system makes it compatible with current restorative techniques in which cores and posts are placed with resin-bonding agents

Activ GP

• Consists of gutta-percha cones impregnated on the external surface with glass ionomer
• Single cones are used with a glass ionomer sealer
• Available in .04 and .06 tapered cones
• Designed to provide a bond between the dentinal canal wall and the master cone

Root Canal Sealers

• The current method for obturating the root canal involves a semi-solid cone or core cemented into the canal with root canal cement, or sealer

Role of Root Canal Sealer

• Close interface by filling irregularities and minor discrepancies between filling material and dentin
• Have antibacterial properties to act against organisms
• Act as a lubricant facilitating the seating of filling cones
• Fill patent accessory canals and multiple foramina

Types of Sealers

• Several types of sealers have been formulated for use in endodontics, with the most common ones based on zinc-oxide-eugenol formulations

Zinc-Oxide-Eugenol Based Sealers

• Include Rickert's sealer, Wach's sealer (zinc oxide powder, oil of clove, and Canada balsam), and Grossman's sealer (catalyst & base) Tubliseal

Medicated Zinc-Oxide Eugenol Sealers

• Constantly release paraformaldehyde, leading to prolonged fixation and antiseptic action
• Includes Endomethasone, N2, and SPAD

Calcium Hydroxide Sealers

• CRCS (calciobiotic root canal sealer)
• Seal apex

Resin-Based Sealers

• Diaket (Polyvinyl resin)
• AH26 (Epoxy resin) & AH Plus (setting time???)
• Epiphany (sets in 25 min) + should be light-cured for 40 sec

Glass Ionomer Sealers

• Have the ability to form an adhesive bond with dentin such as ketac-Endo

Silicone Based Sealers

• The main component is polydimethylsiloxane, instead of showing shrinkage, it shows 0.2% expansion on setting
• Roeko Seal - GuttaFlow(cold flowable matrix to be triturated)

Bioceramic Sealers

• Totalfill or Endosequence
• Composed of zirconium oxide, calcium silicates, calcium phosphate monobasic, calcium hydroxide, and various other components

Techniques of Obturation (How) with Preparation

• Root canal: should be irrigated thoroughly and dried with paper points equivalent to the size of master apical file and adjusted to the proper working length
• Sealer: Follow manufacturer instructions for mixing
• Proper Consistency Tests include the drop and string out test
• Size: equivalent to largest file reaching working length (master apical file)
• Length: the master cone should be equal to the predetermined working length
• The selected master cone is inserted inside the canal until reaching the full working length

Cone Fitness

• Fit tightly in the apical 1/3 of the canal (good tug-back)
• Fit the full working length
• Cannot be forced beyond the apical foramen

Radiographs with Mastered Cones

• A radiograph is exposed to confirm the fitness of the master cone

Mastered Cone Possibilities

• Cone fits to or within 0.5-1mm of working length, tug back and presence of space visible in x-ray lateral to master cone starting from junction between apical and middle one third
• Cone fits short due to dentin chips, ledge formation, or curved canal, Improper 3D shaping of the canal
• Cone fits to or within 0.5-1mm of working length, tug back and absence of space lateral to master cone, has to reshape canal
• Cone passes beyond the apex, use a larger size or cut 1 mm from the tip of the original master cone to increase the tip diameter by 0.02mm until master cone reaches accurate working length
• Cone shows S-shape by x-ray, use a larger cone

Obturation Techniques

• Gutta-percha is a universally used solid core root canal filling material, solid core + sealer
• Gutta-percha can be used in a non-softened or softened form

Non-softened Techniques

• The lateral condensation technique is indicated in most cases except for curved canals

Lateral Condensation Steps

• Selection of master cone (previously mentioned)
• Selection of obturating instruments (spreaders):
  • Spreader of the same size of the master apical size is chosen so it can reach to within 1-2mm shorter than the working length
• Mixing of sealer (previously mentioned)
• Application of sealer inside the canal:
  • The sealer can be carried inside the canal by coating the master cone itself and using it to coat the dentin walls
  • Alternate Instruments like files, reamers or lentulo spirals can be used.
• Obturation procedure: 1- Slow insertion of master cone allow sealer to escape coronally cone in place for 20-30 seconds to ensure fitting 2- Premeasured spreader inside the canal alongside the primary point until it reaches a 1-2mm space short of working length 3- Spreader is left in place for a full minute to allow time for the cone to reconfirm to this pressure

Lateral Condensation Spreaders

• Moved back and forth while withdrawing from the canal to avoid disturbance of the master cone
• Finger spreaders provide better tactile sensation and are less likely to induce fractures in the root when compared with the more traditional hand spreader
• Spreaders made from Ni-Ti provide increased flexibility, reduce stress and provide deeper penetration (light pressure not exceeding 1.5kg is to avoid fracture)
• Auxiliary gutta-percha cone equivalent to the size of the spreader is introduced immediately inside the canal in the space created by the spreader
• The spreader is re inserted again making room for another cone
• The spreading procedure is repeated several times until a spreader can no longer be introduced inside the canal
• Protruding points are severed at the level of the canal orifice with a very hot instrument
• A plugger ensures complete tightness of gutta-percha mass
• Pulp chamber is cleaned to evaluate quality of obturation

Efficacy of Lateral Condensation

• Lateral compaction has with Excellent length control

Disadvantages of Lateral Condensation

• Does not produce a homogeneous mass
• Accessory and master cones are laminated and remain separate and potentially not fill canal irregularities

Radiographic Evaluation for Obturation

• Evaluates Radiolucencies, length, density, taper, and restoration

Lateral Condensation Modification

• Previously described for mature canals,
• In immature canals where no apical constriction exists (tubular canals) or when canals diverge apically (blunderbuss canals) a modification in the master cone has to be done.

The Inverted Cone Technique

• For tubular canals when the largest gutta-percha cone is loose in the canal
• Use a coarse gutta-percha cone which has a serrated butt end and is removed with a scalpel, the cone is inverted and introduced inside the canal
• Follow previously described lateral condensation when cones are at working length

Tailor-Made Cone Technique

• If the tubular canal is too large, a tailor-made cone fabricated is made by heating a number of gutta-percha cones and combining them to form a cone which can tightly fit the canal
• Procedure is a glass slab where the gutta-percha cones are rolled together using a hot spatula, then chilled with a spray of ethyl chloride or ice water to stiffen the gutta-percha
• lateral condensation is followed

Softened Techniques

• Gutta-percha during the condensation inside the canal can better adapt to irregularities in canal anatomy with a better seal than compacted cones
• Can be softened chemically or thermally

Chemically Softened Techniques

• Chemicals soften gutta-percha, with chloroform being the most popular one, although a highly irritant chemical
• Three techniques proposed for chloropercha include the Johnson-Callahan, master cone tip in a dipping dish filled, and Nygard-Ostby techniques

Johnson-Callahan Technique

• Canal is flooded with chloroform, then the gutta-percha master cone is introduced and regular lateral condensation technique is performed

Master Cone Tip Dip Technique

• Dip in chloroform for seconds then introducel.
• canal must be filled with irrigant to prevent the adherence of gutta-percha
• The softened cone is assumed shape canal and wait for an extra seconds after withdraw master cone from canal, wash with water then coat it with sealer for regular lateral condensation

Nygard-Ostby Technique

• A number of gutta-percha cones are placed in a dipping dish filled with chloroform until all form a creamy mix
• A prefitted master cone is dipped in this creamy mix and a regular lateral condensation technique is performed, the chloropercha mix is used as a sealer

Disadvantages of Chemically Softened Techniques

• Chemicals are highly irritant to periapical tissues
• Chemically softened gutta-percha is dimensionally unstable where shrinkage of (12%) occurs after the evaporation of the chemical used leaving voids

Heat Softened Techniques, Thermal Applicators

• Warm lateral condensation technique
• Similar to the non-softened lateral condensation technique, however, the lateral condensation is done by hot spreaders
• Ex. Endotec II

Warm Lateral Compaction

• Adapt master cone the same manner as with traditional lateral compaction
• Select a-size Endotec II tip with various tapers and tip diameters
• Device is activated and the tip is inserted beside the master cone to within 2 to 4 mm of the apex using light pressure
• The tip is rotated clockwise for 5 to 8 seconds and removed counterclockwise, unheated spreader to ensure and then an accessory cone is placed

Warm Vertical Condensation Steps and Considerations

• Dry the root canal with paper points
• Fit the appropriate gutta-percha cone to the radiographic terminus and should visually go to full working length and exhibit tug back
• Remove the cone and cut back about 0.5-2 mm of the tip, reinsert and check the length and tug back
• Select heat transferring material - Select the heat transferring material and prefit the three pluggers to the prepared canal at 5 mm intervals:
  • Widest (coronal), the middle, and the narrowest (to within 3-4 mm of the apical constriction)
• Lightly, coat the walls of the canal with sealer using a handy Lentulo spiral
• Trim excess of the cone in the pulp chamber down the cervical third of the canal transferring heat to the coronal third of the gutta-percha cone
• Use the widest plugger, coated with cement powder, as separating medium and compact the gutta percha in sustained pressure
• First heatwave raises gutta percha 5 to 8 degrees above body temperature
• Second heatwave begins by introducing the heat carrier back into the gutta-percha for 2-3 seconds
• The mid-sized plugger is submerged and compacted
• Third heat wave to to warm the 3-4mm of gutta percha
• The narrowest plugger is immediately inserted in the canal, then compacted vertically to seal the apical foramen
• Apical 'Down-pack' is now completed and place posts as necessary, Inject plasticized gutta- percha with syringes as necessary

Injection Systems

• High-temperature thermoplasticzed injection technique with Obtura
• Consists of pistol-like a delivery unit for the introduction of the gutta-percha beta phase with silver injection tips
• The delivery unit is connected to an electric unit which warms the gutta-percha to the desired temperature, injection needle within working starts 3-5mm close to the site, warm raises causes needle rise
• The canal is coated with a sealer and compacted with pluggers.
• Continued compaction prevents voids
• Affection of shrinks

Low-temperature thermoplasticzed injection technique with Ultrafil 3D

• The device consists of preloaded gutta-percha (alpha phase) filled cannules with gauge stainless steel needles
• Cannules are warmed in a separate heating unit (70 C) then loaded in a special injection syringe
• Canals taperd large to receive a 22-gauge needle and has perfect stops
• Endo Fil-Regular (white cannule), light -bodied - sets in 30 minutes.
• Endo Set (green cannule), heavy-bodied, high-viscosity - sets in 2 minutes.
• Firm Set (blue cannule), less viscosity - sets in 4 minutes.
• Technique similar
• Success depends flared more than usual

Thermomechanical Compactors

• McSpadden compaction technique which uses the compactors rotation speed (8000 - 15000 RPM) friction
• Used and binds easy

Solid Core Gutta-Percha Carriers

• Consist of alpha-phase gutta- percha molded around a metal core resembling an endodontic file carrier
• Carrier sizes stainless titanium plastic and plastic

Guttapercha Carrier Technique

• Coat with sealers
• Select and heat
• Insert slowly
• Cut at the level and compact
• Fill spaces with techniques
• Safe and fast and curves

Apical Constriction of the Canal Notes

• Knowledge of Apical: clinicans needs anatomical skill of what is an ideal sealer propertie
• Properties tackiness mixing seal etc- plastic and antimicrobial- water instability propertties

Advantages of AH-Plus

• Better results of use with the system
• Better quality better toxicity

Intracannal notes

• Division in action: may divide antiseptic purposes the limitations
• ethyl and isolation contents (cmcp)
• Bacteria in canals should be treated with the use of halogens and calcium hydro and anti septics

This lesson covers the final stage of root canal treatment: obturation. It emphasizes achieving total obliteration of the root canal space using non-irritating hermetic sealing agents, preventing bacterial leakage and recurrent infection for long-term success.