|TREATMENT OF THE DEEP CARIOUS LESION
Children and young adults who have not received early and adequate dental care and optimal systemic fluoride and do not have adequate oral hygiene often develop deep carious lesions in the primary and permanent teeth. Many of the lesions appear radiographically to be dangerously close to the pulp or to actually involve the dental pulp. Approximately 75% of the teeth with deep caries have been found from clinical observations to have pulpal exposures.
If a carious exposure discovered at the time of the initial caries excavation could be routinely treated with consistently good results, a major problem in dentistry would be solved. Unfortunately, the treatment of vital exposures, especially in primary teeth, has not been entirely successful. For this reason, clinicians prefer to avoid pulp exposure during the removal of deep caries whenever possible.
A: VITAL PULP THERAPY:
1. INDIRECT PULP TREATMENT (GROSS CARIES REMOVAL OR INDIRECT PULP THERAPY).
The procedure in which only the gross caries is removed from the lesion and the cavity is sealed for a time with a biocompatible material is referred to as indirect pulp treatment.
Indication: Primary and permanent teeth with deep caries that are free of symptoms of painful pulpitis are candidates for this procedure.
The clinical procedure involves:
1. Removing the gross caries but allowing sufficient caries to remain over the pulp horn to avoid exposure of the pulp.
2. The walls of the cavity are extended to sound tooth structure because the presence of carious enamel and dentin at the margins of the cavity will prevent the establishment of an adequate seal (extremely important) during the period of repair.
3. The remaining thin layer of caries in the base of the cavity is covered with a radiopaque biocompatible base material (calcium hydroxide) and sealed with a durable interim restoration (TF).
4. The treated teeth should not be reentered to complete the removal of caries for at least 6 to 8 weeks. During this time the caries process in the deeper layer is arrested.
5. After this period, careful removal of the remaining carious material, now somewhat sclerotic, may reveal a sound base of dentin without an exposure of the pulp. If a sound layer of dentin covers the pulp, the tooth is restored in the conventional manner.
6. Most clinicians are successfully practicing indirect pulp treatment without reentry after the initial caries excavation (single appointment). The inexperienced dentist, however, should perform the treatment in two appointments until confidence in proper case selection has been achieved.
2. DIRECT PULP CAPPING
1. Primary and permanent teeth with small exposures (pinpoint) that have been produced accidentally by trauma or during cavity preparation or to true pinpoint carious exposures that are surrounded by sound dentin.
2. Direct pulp capping should be considered only for teeth in which there is an absence of pain, with the possible exception of discomfort caused by the intake of food.
3. In addition, there should be either no bleeding at the exposure site, as is often the case in a mechanical exposure, or bleeding in an amount that would be considered normal in the absence of a hyperemic or inflamed pulp.
1. All pulp treatment procedures should be carried out under clean conditions using sterile instruments.
2. Use of the rubber dam will help keep the pulp free of external contamination.
3. All peripheral carious tissue should be excavated before excavation is begun on the portion of the carious dentin most likely to result in pulp exposure. Thus most of the bacterially infected tissue will have been removed before actual pulp exposure occurs.
4. Some time distil water used to clean the cavity.
5. A hard-setting calcium hydroxide capping material should be used followed by lining material and permanent restoration (single appointment).
The removal of the coronal portion of the pulp is an accepted procedure for treating both primary and permanent teeth with carious pulp exposures. The justification for this procedure is that the coronal pulp tissue, which is adjacent to the carious exposure, usually contains microorganisms and shows evidence of inflammation and degenerative change. The abnormal tissue can be removed, and the healing can be allowed to take place at the entrance of the pulp canal in an area of essentially normal pulp. Even the pulpotomy procedure, however, is likely to result in a high percentage of failures unless the teeth are carefully selected.
1. Pulpotomy Technique for Permanent Teeth (The calcium hydroxide pulpotomy or vital pulpotomy).
1. This procedure is particularly indicated for permanent teeth with carious pulp exposures when there is a pathologic change in the pulp at the exposure site and with immature root development but with healthy pulp tissue in the root canals.
2. It is also indicated for a permanent tooth with a pulp exposure resulting from crown fracture when the trauma has also produced a root fracture of the same tooth.
3. Only teeth free of symptoms of painful pulpitis are considered for treatment.
1. In the pulpotomy procedure the tooth should first be anesthetized and isolated with the rubber dam.
2. A surgically clean technique should be used throughout the procedure.
3. All remaining dental caries should be removed, as well as the overhanging enamel, to provide good access to coronal pulp.
4. Pain during caries removal and instrumentation may be an indication of faulty anesthetic technique. More often, however, it indicates pulpal hyperemia and inflammation, which makes the tooth a poor risk for vital pulpotomy. If the pulp at the exposure site bleeds excessively after complete removal of caries, the tooth is also a poor risk for vital pulpotomy.
5. The entire roof of the pulp chamber should be removed. No overhanging dentin from the roof of the pulp chamber or pulp horns should remain. No attempt is made to control the hemorrhage until the coronal pulp has been amputated.
6. A funnel-shaped access to the entrance of the root canals should be produced.
7. A sharp discoid spoon excavator, large enough to extend across the entrance of the individual root canals, may be used to amputate the coronal pulp at its entrance into the canals.
8. The pulp stumps should be cleanly excised with no tags of tissue extending across the floor of the pulp chamber.
9. The pulp chamber should then be irrigated with a light flow of water from the water syringe and evacuated.
10. Cotton pellets moistened with water should be placed in the pulp chamber and allowed to remain over the pulp stumps until a clot forms.
11. The placement of a calcium hydroxide capping material over the pulp tissue remaining in the canals.
12. A protective layer of hard-setting cement is placed over the calcium hydroxide to provide an adequate seal.
13. The procedure is completed during a single appointment.
14. The tooth is subsequently prepared for full-coverage restoration.
15. Endodontic treatment is indicated if the tooth is to be saved.
Prognosis: After 1 year, a tooth that has been treated successfully with a pulpotomy should have a normal periodontal ligament and lamina dura, radiographic evidence of a calcified bridge if calcium hydroxide was used as the capping material, and no radiographic evidence of internal resorption or pathologic resorption. The treatment of permanent teeth by the calcium hydroxide method has resulted in a higher rate of success when the teeth are selected carefully based on existing knowledge of diagnostic techniques.
Pulpotomy Technique for Primary Teeth (Fixed pulpotomy or Formocresol pulpotomy).
1. This procedure is particularly indicated for primary teeth with carious pulp exposures when there is a pathologic change in the pulp at the exposure site and with healthy pulp tissue in the root canals.
2. It can be used in permanent teeth as a temporary treatment which should change sooner or later to endodontic treatment.
3. Only teeth free of symptoms of painful pulpitis are considered for treatment.
1. The treatment is also completed during a single appointment.
2. A surgically clean technique should be used.
3. The coronal portion of the pulp should be amputated as described previously, the debris should be removed from the chamber, and the hemorrhage should be controlled.
4. If there is evidence of hyperemia after the removal of the coronal pulp, which indicates that inflammation is present in the tissue beyond the coronal portion of the pulp, the technique should be abandoned in favor of the partial pulpectomy or the removal of the tooth.
5. If the hemorrhage is controlled readily and the pulp stumps appear normal, it may be assumed that the pulp tissue in the canals is normal, and it is possible to proceed with the pulpotomy.
6. The pulp chamber is dried with sterile cotton pellets.
7. Next, a pellet of cotton moistened with a 1:5 concentration of Buckley's formocresol and blotted on sterile gauze to remove the excess is placed in contact with the pulp stumps and is allowed to remain for 5 minutes. Because formocresol is caustic, care must be taken to avoid contact with the gingival tissues.
8. The pellets are then removed, and the pulp chamber is dried with new pellets.
9. A thick paste of hard-setting zinc oxide- eugenol is prepared and placed over the pulp stumps.
10. The tooth is then restored with permanent filling or stainless steel crown.
The original Buckley's formula for formocresol calls for equal parts of formaldehyde and cresol. The 1:5 concentration of this formula is prepared by first thoroughly mixing three parts of glycerin with one part of distilled water, then adding four parts of this diluent to one part of Buckley's formocresol, and thoroughly mixing again.
Some dentists prefer to make the pulp-capping material by mixing the zinc oxide powder with equal parts of eugenol and formocresol.