Endodontic techniques in deciduous teeth (pulpectomy)

The stages of endodontic treatment

Instruments for obturation of the pulp space.

Rotary paste fillers (Lentulo) made for contra-angle handpiece, they can also be rotated clockwise by finger action. Used for placing initial sealer before solid core root fillings or completely filling the canal with paste filling.

Spreader is the instrument for lateral compaction of gutta-percha points.

Plagger is used for vertical compaction softened by heating gutta-percha.

1. Anaesthesia.

2. Isolation of the tooth.

3. Performing of access to root canals.

The principles of endodontic coronal cavity preparation:

- outline form;

- convenience form;

- removal of the remaining carious dentin (and de­fective restorations);

- toilet of the cavity;

4. Initial debridement of root canal (with using of files or barbed broaches; barbed broaches – short-handled instruments used primarily for vital pulp extirpation; they are also used to loosen debris in necrotic canals or to remove paper points or cotton pellets from within the root canal).

5. Determination of length of tooth (by radiographic or electrical method).

6. Instrumental cleaning and shaping of canal.

7. Irrigation of canal.

8. Canal obturation.

9. Tooth restoring.

Points 1-5 perform in children’s teeth the same way as in adult. Let’s consider the features of cleaning, shaping and irrigation of root canals in temporary and in immature permanent teeth.

Under local analgesia and rubber dam, all accessible radicular pulp tissue is removed with broaches. No attempt should be made to instrument beyond the apex. The canals should be filed with the aim of enlarging them to permit condensation of root-canal filling mate­rial. A diagnostic file radiograph is not needed to access root length but is desirable if practical, as in endodontically treated permanent teeth. Visual comparison of file and root-canal length on the preoperative periapical radiograph will result in sufficient clinical accuracy.

The multiple ramifications of the radicular pulp in a primary molar make complete debridement impossible. Also, the ribbon shape of the root canals, with a narrow mesiodistal width compared to their buccolingual dimen­sion, discourages gross enlargement of the canals. In permanent teeth the object of mechanical preparation is to provide an even, circular, apical one-third of the canal which will be obliterated with an accurately fitting master point. In the primary tooth, attempts to prepare a circular apical one-third mechanically may result in lateral perforation of the canal because of its hour-glass shape. Because of the bizarre anatomy of the root canals the use of barbed broaches as in conventional endodontics may be unsuccessful; at the worst there is increased danger of instrument fracture. Rather, a combined biomechanical preparation of the canals is preferred.

Instruments used in conjunction with irriga­ting solutions reduce the possibility of fracture, because of the lubricant action of the solution. A 0.5-1% solution of sodium hypochlorite has an excellent solvent action and is dilute enough to cause only mild irritation when contacting periapical tissue. It can be used in a small (15-ml) syringe fitted with a 25-gauge (32-mm) needle; provided the needle fits loosely in the canal there is no danger of forcing debris apically. It should be followed by repeated flushings with normal saline to ensure the removal of all debris.

Hedstrom files, No.15 or No.20, are strongly recommended since they remove hard tissue only on withdrawal, which prevents pushing infected material through the apices (the max­imum size used should be No.30). For this reason, reamers are definitely not recom­mended. The limited amount of mouth opening may make access difficult. This can be improved by routinely using a mouth prop and bending the file handles to gain access to the mesial canals of first and second primary molars. The canals should be instrumented to the resistance point; this is evident by tactile sensation and usually corresponds to a curvature in the apical one-third of the root. Each canal should be enlarged three or four instrument sizes greater than the first file capable of working the apex.

After filing, the canals should be irrigated many times (at least 10 flushings are recom­mended) with saline or antiseptic solution, followed by drying with paper points. A small pledget of cotton wool moist with formocresol is placed in the pulp chamber for 3 min. This is used to “fix” any remaining pulp tissue in the apical 1-2 mm and any accessory canals that may be present in the floor of the pulp chamber.

Sometimes multivisit pulpectomy must be performed. The multivisit pulpectomy is indicated where infection, an abscess or a chronic sinus exist. The clinical technique is similar to that of the single-visit pulpectomy. After instrumentation the canals are irrigated as described before. Between appointments an antibacterial drug, such as dilute formocresol, paramonochlorphenol, Ledermix or calcium hydroxide is sealed in the pulp chamber, maintained with a temporary dressing.

Дата добавления: 2014-01-05