obturation

بسم الله الرحمن الرحيم

ENDODONTICS

Assist prof. Dr.Emad Farhan Alkhalidi
B.D.S., M.Sc., PhD.
Conservative Department
Obturation Of Root Canal System

• To eliminate all avenues of leakage from the oral cavity or the periradicular tissues into the root canal system,
• (2) To seal within the system any irritants that cannot be fully removed during canal cleaning and shaping procedures. (e.g., microorganisms, toxins, metabolites) and products of pulp tissue degeneration

CLEAN

SHAPE
FILL
OBTURATION
ACCESS
DISINFECTION
BIO-MECHANICAL PREP.
Root Canal Therapy


• ● to prevent reinfection of the cleaned canal system from the coronal end
• ● to prevent percolation of periradicular exudate into the root canal space
• ● to seal remaining bacteria within the root canal system.

• Criteria for filling

• Abscence of pain and swelling
• No tenderness to percussion
• Abscence of tenderness to palpation of the asociated oral mucosa
• No demonstrable patent sinus
• Abscence of persistent exudate in the canal ( dry canal)
• An odour-free canal

EXTENSION OF THE ROOT CANAL FILLING

The anatomic limits of the pulp space are the dentinocemental junction apically, and the pulp chamber coronally.
Canals filled to the apical dentinocemental junction are filled to the anatomic limit of the canal. Beyond this point, the periodontal structures begin.
The dentinocemental junction is an average of about 0.5 to 0.7 mm from the external surface of the apical foramen,

Properties of Root canal filling materials

Ideally, a root canal filling material should:
● be easily introduced into the root canal
● not irritate periradicular tissues
● not shrink after insertion
● seal the root canal laterally, apically and coronally
● be impervious to moisture
● be sterile or easily sterilised before insertion
● be bacteriostatic or at least not encourage bacterial growth
● be radio-opaque
● not stain tooth structure or gingival tissues
● be easily removed from the canal as necessary.


Ideally, a sealer should:
● satisfy the above requirements of a root filling material
● provide good adhesion to the canal wall
● have fine powder particles to allow easy mixing or be a two paste system
● set slowly.

Types of root filling material available

Solid and semisolid materials include gutta-percha and
silver points.
Silver points : 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 disadvantage are that silver cones are round in cross section, therefore they can not be used in oval cross sectioned canals, and silver cones may produce corrosion products which will be harmful to the periapical region.

Sealers/Cements

The use of a sealer during root canal obturation is essential for success. It enhances the seal and serves as filler for canal irregularities and minor discrepancies between the root canal wall and core filling material. Sealers are often expressed through lateral or accessory canals, and they can assist in microbial control should there be microorganisms left on the root canal walls or in the tubules.
Sealers can also serve as lubricants to assist in the thorough seating of the core filling material during compaction.
Sealers can be grouped based on their prime constituent or structure, such as zinc oxide-eugenol, calcium hydroxide, resins, glass ionomers, or silicones.

Pulp canal sealer

AH plus sealer

Gutta-Percha

Gutta-percha the most commonly used semi solid root canal filling material. It demonstrates minimal toxicity, minimal tissue irritability, and is the least allergenic material. In cases of inadvertent gutta-percha cone overextension into the periradicular tissues, it is considered as being well tolerated as long as the canal is clean and sealed.
The composition of the available gutta-percha cones is approximately 19% to 22% gutta-percha, 59% to 75% zinc oxide, with the remaining small percentages a combination of various waxes, coloring agents, antioxidants, and metallic salts.


gutta-percha either standardized cone or non-standardized cone.
(a) standardized cone : it is designed to have the same size & tapering of the corresponding intra canal instrument as master cone.
(b) non-standardized cone; this cone has greater tapering in which fine tip & heavy body ,its used with master cone to aid it in obturation.

Gutta-percha filling techniques

Each of the techniques will produce acceptable clinical results if used correctly.
● single cone (not recommended as it does not seal laterally and coronally)
● lateral condensation
● thermomechanical compaction
● vertical condensation
● thermoplasticised gutta-percha
● carrier-based techniques.

(lateral condensation)

Procedure of master cone selection(the cone that occupies most of the root canal parts):-
the master cone selected should have the same size of the M.A.F(master apical file) and it should have the same length of the full working length.
The master cone should need some force to be seated inside the canal and some force is required to dislodge the master cone from the canal. This is called tug-back. This resistance of removal of the master cone enhances the sealing ability at the apical area of the root canal.

Gutta percha

If the master cone goes to the full working length but its loose inside the canal , we take larger gutta-percha cone or we remove 1mm from the apical end of the master cone to increase the width of the master cone.
Verify the master cone position with a radiograph to ensure the optimum fitness.



Mix the sealer and coat the wall by picking up sealer on M.A.F and spin it counter-clockwise . once the M.A.F is rotated , there will painting of the walls with the sealer.
Dip the tip of master cone in the sealer and seat it in the root canal.




• By the use of the spreader the master cone is pushed laterally and apically providing room for auxiliary gutta-percha point . the spreader should rotate 180o (to the right and left) until it becomes loose and pushed out side.
• The spreader should penetrate the apical 1\3 (a rubber stopper should be placed to mark the length of penetration 2-3mm. from the tip of the master cone)
• Place an auxiliary cone (which is smaller than the master cone )after its tip is dipped in the sealer.





repeat the process by more gutta-percha points and more spreading until the entire canal is filled when the spreader cant be placed beyond the cervical line of the root canal.
take aradiograph to check the obturation mass.
a hot instrument is used to cut the excess gutta-percha to just below the cervical line. The instrument used can be either an excavator or ash no.6 and should be very hot to cut in one motion. If the instrument is not hot enough then the master cone might be dislodged.
aplugger is used for vertical condensation to assure tightness of the condensation.
all the sealer and gutta-percha should be removed from the pulp chamber by a round bur.
the cement base material and a coronal restoration are placed in the tooth..