Lection 5Stopping of root canals. Instruments for obturation of root canals, standards of ISO. Filling materials. Classification. Composition, properties. Modern technologies of stopping of root canals: stopping of root canals by the method of central pins, vertical condensation of gutta– percha, cold and warm lateral  condensation of gutta– percha, obturation of root canals by the system of “Thermaphil”. Errors and complications

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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

Gutta-percha filling techniquesEach of the techniques (except where indicated) will produce acceptable clinical results if used correctly.

Proponents exist for the different techniques, although personal preference usually determines the final choice:

-single cone (not recommended as it does not seallaterally and coronally)-lateral condensation-thermomechanical compaction-vertical condensation-thermoplasticised gutta-percha-carrier-based techniques.

Stopping by a gutta-percha. Stopping of root-canals by a gutta-percha takes certain advantages before other methods. It provides more reliable filling of channel and pressurizing of the apex opening. Pressure, that he

is created by instruments during condensation of warmed-up gutta-percha, provides its penetration in the add forks of root-canal and in all his difficult anatomic system. A gutta-percha does not dissolve in water tissue liquid which guarantees the protracted and reliable filling of root-canal and his isolation from fabrics of perіodont. On condition of correct implementation of method of stopping she practically does not hatch for the apex of tooth and does not injure perіodont. And in the end, a gutta-

percha is biologically very inert material, that is why its application practically does not result in annoying fabrics of perіodont and organism

on the whole.

Stopping of root-canals by a termaplastic gutta-percha. One of lacks of the use of gutta-percha there is

considerable enough complication of methods of stopping in endodontical practice. With the purpose of his removal

methods of stopping of root-canals by a gutta-percha perfect constantly. The systems, in which it is foreseen the

use of £- and ß-gutta-percha, combination of injection method of filling of root-canals with condensation

application ß-gutta-percha, are developed. Yes, the system of "Endodontic Alfa concepts" (THE USA) consists of £- and ß-gutta-percha in the special plastic syringes-tubas, I

will build on for thermal softening influence of gutta-percha, filler of root-canals and angular tip with low speed

of rotation.

Stopping by pins is in combination with the fillers.This method foresees the use of pin (detective) in combination with plastic solidifiable

material (seelers). For this purpose use different pins: silver, titanic, gutta-perchas, plastic. The use of pin and his introduction to the root-canal provides the best condensation and more

dense adjoining of plastic stopping material to the walls of channel, is instrumental in more reliable filling of the apex opening and speed up the process of stopping. Size and length of pin is determined on the size of the last instrument (file) used for expansion of channel. On

select pin by the coniferous forest mark working length of root-canal. By a root needle or root filler a channel is filled by plastic solidifiable material (seeler), by a select doctor depending on a concrete clinical situation. After it at him enter preliminary covered by the skim of the involved stopping material pin, carefully moving forward depth first on the marked working length to the physiology narrowing of channel. Pin is brought into a root-canal slowly, that,

from one side, allows evenly to distribute forces of eras in a channel, and from other — prevents the leadingout of stopping material for the apex of root. Surplus of stopping material

in устях is deleted, and part of pins which comes forward in the cavity of tooth, break (on metallic pins for this purpose preliminary by the coniferous forest notch at level устя of

channels) off or cut away by the coniferous forest. Gutta-percha pin is cut away by a warmed-up flatter or power-shovel.

Method of central pin, or one cone. This method is applied in those cases, when a root-canal is

relatively direct and wide relatively by parallel walls. Determining size of central pin (master

point) of gutta-percha, it is needed to watch after that he was densely enough and tightly included in

a root-canal in apical to his part, instead of in initial third of channel. If as a result of large size of channel it is not succeeded to pick up standard pin of gutta-percha, he is made from two-three pin of

less size. they are warmed up to softening influence on flame of spirit-lamp and then on a glass plate

twist up together in the cone of greater diameter.

•Cold lateral condensation of gutta-percha. A method is recommended during filling of wide and distorted channels in which

it is heavy valuably to drive in central pin. Often enough such channels have an oval or even wrong geometrical form on a

transverse section. Special attention during treatment and forming of such channels give to creation of апікального appearance which prevents the leading out of stopping material for the apex of root of tooth. For stopping pick up three spreaders of the proper diameter. By one spreader (with the least diameter of working part) operate in

apical part of channel, second — in middle and third (with most diameter) — in mouth. The diameter of working part of select

spreader must make approximately two third of diameter of the proper part of root-canal. Pick up for 2-3 standard   of gutta-percha from diameter, that answers the diameter of the proper spreaders, and plugger, the diameter of working part of which is evened 2/3

diameters mouth of channel.

FILE FILE - - EZEEZE

Radiograph showing how vertical condensation helpsobturate complex canal anatomy. Note that the mesial root

has three canals with an interconnecting web runningbetween them. The distal root has two canals and an apical

bifurcation.