Apexification is a procedure used primarily on devitalized (dead) juvenile teeth with incomplete root growth. The goal of apexification is to create a natural or artificial hard substance barrier at the root apex, without which a dense root filling of the tooth is not possible. Teeth with completed root growth have an apical constriction (narrowed area at the root tip) at the apex, where the root canal has the narrowest cross-section due to hard substance accumulation. Without this constriction, when a tooth is root-filled, there is a risk of spilling material into the surrounding apical tissue, bone, and, when treated in the maxilla, the maxillary sinus.
Indications (areas of application)
Although the apexification procedure is primarily used in cases where root growth has not yet been completed, in principle, all applications are considered where the goal is to create apical constriction:
- Irreversible pulpitis (irreversible pulp inflammation) of a vital tooth with incomplete root growth, after trauma or caries-related;
- Immature tooth after trauma that does not yet show pulpitis, but in which revascularization (reconnection of the nerve-vascular bundle that forms the pulp, torn off during trauma), has not occurred over a long period of observation;
- Devitalized (dead) tooth with incomplete root growth and initial radiographic signs of root resorption;
- Originally mature tooth with completed root growth, which due to caries or trauma (dental accident) shows root resorption from apical (starting from the root tip) and consequently no longer has apical constriction;
- Root transverse fracture.
The procedures
The calcium hydroxide process and the MTA process are applied. While the former causes apexification through natural hard substance formation over 6 to 18 months, the use of MTA creates an artificial hard substance barrier and definitively (finally) restores the tooth within a comparatively short time. Since juvenile teeth have a very large root canal lumen (cavity), there is a high risk of losing them through fracture (breakage) while waiting for hard substance formation, since the soft permanent medicinal calcium hydroxide inlays do not stabilize the tooth. For both procedures, it should be said equally that any endodontic treatment (treatment of the root canal system including the root tip) can only be as good as the subsequent bacteria-proof restoration of the tooth crown, which must permanently prevent bacteria from entering the root canal. 1. calcium hydroxide procedure
Calcium hydroxide reactively slowly stimulates the formation of new tooth structure in the apical (root apex) area via its strongly basic pH, and is therefore also used to directly cap the pulp (tooth pulp) after it has been opened.
- If possible, the treatment should be carried out in each case under absolute drainage;
- Extirpation of the necrotic pulp tissue (removal of the dead pulp);
- Mechanical cleaning: Chipping of root canal wall material using root canal instruments (e.g., reamers and files);
- Chemical removal of the smear layer (the smear layer deposited on the root canal wall) with ethylenediaminetetraacetic acid (EDTA);
- Chemical disinfection with root canal irrigants (e.g. hypochlorite);
- Drying with paper seats;
- Introduction of calcium hydroxide and subsequent compaction;
- X-ray control every three months;
- Simultaneous renewal of calcium hydroxide inlay as a temporary (time-limited) root filling;
- In the case of radiographically detectable apexification: final root canal filling.
2. MTA procedure
Mineral trioxide aggregate, or MTA, is a Portland cement derivative. The powder contains calcium silicates, bismuth oxide, calcium sulfate and aluminum compounds and reaches a pH of 12.5 after mixing with distilled water, so also has a strong basic effect. Unlike calcium hydroxide, the material sets to a solid cement within four hours.
- If possible, absolute drying;
- Extirpation;
- Mechanical cleaning;
- Chemical removal of the smear layer;
- Chemical disinfection;
- Drying with paper tips;
- Introduction of calcium hydroxide for about a week;
- After one week, removal of calcium hydroxide, disinfecting rinsing, drying;
- Direct apexification: insertion of a layer of MTA approximately 5 mm high in the apical area (root apex area) and compaction using a hand plunger (tamping instrument); optionally, an absorbable material can be inserted in advance, against which the MTA cement can then be compacted with light tamping pressure. This reduces the risk of MTA overstuffing.
- Insertion of a wet paper tip on the cement, which is supplied with water from it during setting;
- Temporary supply;
- The following day: removal of the paper tip, drying, final root canal filling with conventional materials (gutta-percha and sealer).
