Technique of resorcinol-formalin method
Methods of processing of impassable canals.
When impossible to remove the pulp or decay from the root canal (curved roots and root canals, a significant narrowing, broken instruments in the root canal and other cases) have resorted to special treatment in order to transform them into harmless aseptic cord. For this purpose, use the impregnation methods.
Impregnation is soaking the contents of the impassable root canal with antiseptic substances capable of deep diffuse and transform it into an aseptic cord or glassy mass, long time do not expose of the putrefactive decay.
Mummification is prevention of microbial degradation of the pulp by soaking it potent antiseptics (thymol, camphor, iodoform, cresol, parahlorfenol etc.). For this purpose at the mouth of the root canals put a cotton tampon moistened with potent, slowly absorbable antiseptics or paste containing mummified material and the tooth filling.
For impregnation (soaking) pulp of the root are using following techniques: resorcinol-formalin and of silvering methods.
Resorcinol-formalin method.
This method provides for the holding of the transformation of the pulp or the decay in the impassable part of the root canal in like plastic aseptic cord, not affected by dissolution or disintegration under the influence of microorganisms and tissue fluid.
It should be remembered that before the impregnation of the pulp in the canal should be necessarily devitalized, as impregnation of vital pulp is inefficient and leads to a "residual pulpitis."
Reagents for resorcinol-formalin method:
Rp: Sol. Formalini 40 % - 50,0
D.S. For the preparation of resorcinol-formaldehyde mixture.
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Rp. Resorcini 25,0
D.S. For the preparation of resorcinol-formaldehyde mixture.
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Rp: Sol. Natrii caustici 1 % - 25,0
D.S. The catalyst for the resorcinol-formaldehyde mixture.
Technique of resorcinol-formalin method.
At first dissected cavity, open cavity of the tooth and create endodontic access. After that doctor determine the permeability of root canals. Good cross canals mechanically and with medications treated and filled. Impassable root canals treated as cross-country, are expanding funnel-shaped their mouth, necrotizing pulp impassable section of the canal (either by devitalized paste or conduct electrochemical necrosis) and proceed to impregnation.
We want to emphasize that the impregnation should be conducted on necrotic pulp. Impregnation of the vital pulp is not effective!
Resorcinol-formalin impregnation method (method of Albrecht) necessarily is carried out in 3-4 visits (no less!).
In the first visit spend processing of resorcinol-formalin mixture (method of Albrecht) without a catalyst. The method of mixing: on the glass are placed 5-6 drops of formalin, and then it is added up to saturation crystalline resorcinol. Resorcinol is stirred (not rub!) in formalin with metal spatula. About saturation of the solution is indicate termination dissolving of resorcinol - a few crystals remain undissolved. Then carried out impregnation of content of impassable part of the canal with mixture. The tooth is isolated from saliva and dried. At the mouth of the canal with a pipette or cheeks of tweezers are placed 1-2 drops of resorcinol-formalin liquid and pumped into passable part of the canal with endodontic instruments for 3 minutes.
The residue of the mixture is removed with a cotton swab, to the mouth of the canal are placed a new portion of fluid and re-injected into the canal for 3 minutes. This operation is performed three times. Then, on the mouth of the impassable canal impose a cotton swab soaked in a mixture of resorcinol-formalin (without a catalyst!) and filled with a hermetic bandage made of artificial dentin. Prescribe a repeat visit within 1-2 days.
During the second visit hermetic bandage is removed, again conducting impregnation with resorcinol-formalin liquid without a catalyst using the same method as in the first visit. Over the mouths of impassable canals again leave a swab soaked resorcinol-formalin liquid without a catalyst, and the cavity hermetically filled with bandage of artificial dentin. The next visit is also prescribed in 1-2 days. In the third visit hermetic bandage is removed and spend impregnation with resorcinol-formalin liquid and the catalyst.
Method of preparation of resorcinol-formalin liquid with catalyst: on the glass is prepared resorcinol-formaldehyde mixture with the method described above, then it add 2-3 drops of solution of Natrii caustici (catalyst) and the liquid on the glass thoroughly mixing. Resorcinol-formalin mixture after the using catalyst polymerizes to phenol-formaldehyde plastic. As a result of the pulp with the microorganisms as it is in this glass-walled mass, not exposed to decay.
Producing treatment of impassable root canals with the method which described above (3 times for 3 minutes). After that, the excess of liquid is removed with a cotton swab and passable part of the canal fills with resorcinol-formalin pasta (resorcinol-formalin liquid with catalyst, mixed with zinc oxide to consistence of a paste). At the mouth of the canals is applied isolating liner, the crown of the tooth is reduced with permanent filling material.
Silvering method.
Conducting silvering method involves soaking of the impassable root canal with silver nitrate. After the restoring of silver, on the walls of the micro-and macro canals deposited thin film of metallic silver ("silver mirror reaction"), "walled up" microflora in the thickness of dentin. The interaction of silver with proteins produced pulp albuminates silver that "conserved" pulp, turning it into an aseptic cord, not subjected ichorization. Furthermore, the presence of silver in the canal, which has a long antiseptic (or rather, oligodynamic) action, prevents the growth of microorganisms and the development of inflammatory complications of apical periodontitis.
Reagents for silvering method:
Rp: Sol. Argenti nitratis 30 % - 10,0
D.S. For impregnation of root canals
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Rp: Sol. Hydrochinoni 4 % -10,0
D.S. For recovery of silver nitrate.
It should be remembered that before the method of silvering, as well as resorcinol-formalin method, the pulp in the canal should be necessarily devitalizing.
Impregnation of method silvering also must necessarily be conducted in 3-4 visits (no less!).
In the first visit conduct soaking of impassable canal with 30 % aqueous solution of silver nitrate. The tooth is isolated from saliva and dried. At the mouth of the canal with a pipette or cheeks of tweezers are placed 1-2 drops of silver liquid and pumped into passable part of the canal with endodontic instruments for 3 minutes.
The residue of the mixture is removed with a cotton swab, to the mouth of the canal are placed a new portion of fluid and re-injected into the canal for 3 minutes. This operation is performed three times. Then, on mouth of the canal with a pipette or cheeks of tweezers put 1-2 drops of reducer – 4 % solution of hydrochinoni (by Pekker) or a mixture of 30 % ammonia and 10 % formalin in the ratio 1:1, prepared ex tempore (by Platonov).
Reducing agent is injected into passable part of the canal with endodontic instruments for 3 minutes. Tooth cavity after introduction into it reducer is dark gray in color due to deposition on the walls of metallic silver.
Finally, at the mouth of the canals of impassable is applied a cotton swab soaked in 30 % aqueous solution of silver nitrate and filled with hermetic bandage of artificial dentin. Prescribe second visit within 1-2 days.
During the second visit hermetic bandage is removed, again conducting impregnation with the same method as in the first visit - 3 times for 3 minutes treated with solution of silver nitrate, and then during 3 minutes injected reducer.
Over the mouths of impassable canals again leave a swab soaked with 30 % solution of silver nitrate and the cavity hermetically filled with bandage of artificial dentin. The next visit is also prescribed in 1-2 days. In the third visit hermetic bandage is removed and spend impregnation by the same method as in previous visits. After that, the excess of liquid is removed with a cotton swab and passable part of the canal fills with a hardening paste.
During method of silvering reducer used in every visit, is even allowed to leave the swab soaked in reductant above the mouths of the canals between visits. In addition, it should be underline that, in conducting method of silvering in the teeth of the upper jaw is recommended to use reducer by Platonov - a mixture of 30 % of ammonia and 10 % formalin in the ratio 1:1, prepared ex tempore. This is due to the fact that both of these components to form pairs that are better than hydroquinone penetrate the channels of the upper jaw.