Treatment of Deep Caries, Vital Pulp Exposure, and Pulpless Teeth

Chapter 19. Treatment of Deep Caries, Vital Pulp Exposure, and Pulpless Teeth.

OBJECTIVES. The treatment of the dental pulp exposed by the caries process, by accident during cavity preparation, or even as a result of injury and fracture of the tooth. To learn regarding the control of infection and inflammation in the vital pulp. Current methods of diagnosing the extent of pulpal injury. Effective methods of pulp therapy..

DIAGNOSTIC AIDS IN THE SELECTION OF TEETH FOR VITAL PULP THERAPY.

History of pain. The history of presence or absence of pain may not be as reliable in the differential diagnosis of the condition of the exposed primary pulp as it is in permanent teeth. Degeneration of primary pulp even to the point of abscess formation without the child's recalling pain or discomfort is not uncommon. Nevertheless, the history of a toothache should be the first consideration in the selection of teeth for vital pulp therapy. A toothache coincident with or immediately after a meal may not indicate extensive pulpal inflammation. The pain may be caused by an accumulation of food within a carious lesion, by pressure, or by a chemical irritation to vital pulp protected by only a thin layer of intact dentin. A severe toothache at night usually signals extensive degeneration of the pulp and calls for more than a conservative type of pulp therapy. A spontaneous toothache of more than momentary duration occurring at any time usually means that pulpal disease has progressed too far for treatment with even a pulpotomy..

Clinical signs and symptoms. A gingival abscess or a draining fistula associated with a tooth with a deep carious lesion is an obvious clinical sign of an irreversibly diseased pulp. Such infections can be resolved only by successful endodontic therapy or extraction of the tooth. Abnormal tooth mobility is another clinical sign that may indicate a severely diseased pulp. When such a tooth is evaluated for mobility, the manipulation may elicit localized pain in the area, but this is not always the case. If pain is absent or minimal during manipulation of the diseased mobile tooth, the pulp is probably in a more advanced and chronic degenerative condition. Pathologic mobility must be distinguished from normal mobility in primary teeth near exfoliation. Sensitivity to percussion or pressure is a clinical symptom suggestive of at least some degree of pulpal disease, but the degenerative stage of the pulp is probably of the acute inflammatory type. Tooth mobility or sensitivity to percussion or pressure may be a clinical signal of other dental problems as well, such as a high restoration or advanced periodontal disease. However, when this clinical information is identified in a child and is associated with a tooth having a deep carious lesion, the problem is most likely to be caused by pulpal disease and possibly by inflammatory involvement of the periodontal ligament..

RADIOGRAPHIC INTERPRETATION. A recent x-ray film must be available to examine for evidence of periradicular or periapical changes, such as thickening of the periodontal ligament or rarefaction of the supporting bone. These conditions almost always rule out treatment other than an endodontic procedure or extraction of the tooth. Radiographic interpretation is more difficult in children than in adults. The permanent teeth may have incompletely formed root ends, giving an impression of periapical radiolucency, and the roots of the primary teeth undergoing even normal physiologic resorption often present a misleading picture or one suggestive of pathologic change..

The proximity of carious lesions to the pulp cannot always be determined accurately in the x-ray film. What often appears to be an intact barrier of secondary dentin protecting the pulp may actually be a perforated mass of irregularly calcified and carious material. The pulp beneath this material may have extensive inflammation.

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Pulp testing. The value of the electric pulp test in determining the condition of the pulp of primary teeth is questionable, although it will give an indication of whether the pulp is vital. The test does not provide reliable evidence of the degree of inflammation of the pulp. A complicating factor is the occasional positive response to the test in a tooth with a necrotic pulp if the content of the canals is liquid. The reliability of the pulp test for the young child can also be questioned sometimes because of the child’s apprehension associated with the test itself. Thermal tests have reliability problems in the primary dentition, too. The lack of reliability is possibly related to the young child’s inability to understand the tests..

The value of the electric pulp test in determining the condition of the pulp of primary teeth is questionable, although it will give an indication of whether the pulp is vital. The test does not provide reliable evidence of the degree of inflammation of the pulp. A complicating factor is the occasional positive response to the test in a tooth with a necrotic pulp if the content of the canals is liquid. The reliability of the pulp test for the young child can also be questioned sometimes because of the child’s apprehension associated with the test itself. Thermal tests have reliability problems in the primary dentition, too. The lack of reliability is possibly related to the young child’s inability to understand the tests Several methods have been developed and advocated as noninvasive techniques for recording the blood flow in human dental pulp. Two of these methods include the use of a laser Doppler flowmeter and transmitted-light photoplethysmography..

Physical condition of the patient. Although the local observations are of extreme importance in the selection of cases for vital pulp therapy, the dentist must also consider the physical condition of the patient. In seriously ill children, extraction of the involved tooth after proper premedication with antibiotics, rather than pulp therapy, should be the treatment of choice. Children with conditions that render them susceptible to subacute bacterial endocarditis or those with nephritis, leukemia, solid tumors, idiopathic cyclic neutropenia, or any condition that causes cyclic or chronic depression of granulocyte and polymorphonuclear leukocyte counts should not be subjected to the possibility of an acute infection resulting from failed pulp therapy. Occasionally, pulp therapy for a tooth of a chronically ill child may be justified, but only after careful consideration is given to the prognosis of the child’s general condition, the prognosis of the endodontic therapy, and the relative importance of retaining the involved tooth..

EVALUATION OF TREATMENT PROGNOSIS BEFORE PULP THERAPY.

Other factors to consider include the following: 1. The level of patient and parent cooperation and motivation in receiving the treatment 2. The level of patient and parent desire and motivation in maintaining oral health and hygiene 3. The caries activity of the patient and the overall prognosis of oral rehabilitation 4. The stage of dental development of the patient 5. The degree of difficulty anticipated in adequately performing the pulp therapy (instrumentation) in the particular case 6. Space management issues resulting from previous extractions, preexisting malocclusion, ankylosis, congenitally missing teeth, and space loss caused by the extensive carious destruction of teeth and subsequent drifting 7. Excessive extrusion of the pulpally involved tooth resulting from the absence of opposing teeth These examples, in any combination, illustrate the almost infinite number of treatment considerations that could be important in an individual patient with pulpal pathosis ..

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. They also showed that well over 90% of the asymptomatic teeth with deep carious lesions could be successfully treated without pulp exposure using indirect pulp therapy techniques. This procedure is described herein. 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..

INDIRECT PULP TREATMENT. 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..

The clinical procedure involves removing the gross caries but allowing sufficient caries to remain over the pulp horn to avoid exposure of the pulp. 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. The remaining thin layer of caries in the base of the cavity is covered with a radiopaque biocompatible base material and sealed with a durable interim restoration..

Other operative procedures can be performed at subsequent visits. However, 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. At the conclusion of the minimum 6 to 8 week waiting period, the tooth is reentered. 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.

Successful treatment occurred in 32 of the 34 teeth that were available for the 6-month evaluation procedure. In all cases of successful treatment the base material and the residual carious dentin were observed to be dry on reentry and clinical examination. Of the successfully treated teeth, only four had residual carious dentin that felt somewhat soft when probed with an explorer, in the remainder the dentin felt hard. Pinto and colleagues showed similar dentin consistency results, as well as significantly decreased bacterial counts at the end of treatment. Indirect pulp therapy has been proved to be a valuable therapeutic procedure in treating asymptomatic teeth with deep carious lesions. The procedure reduces the risk of direct pulp exposure and preserves pulp vitality. One may question the need to reenter the tooth if it has been properly selected and monitored, if a durable restoration is placed initially, and if no adverse signs or symptoms develop. Most clinicians are successfully practicing indirect pulp treatment without reentry after the initial caries excavation. The inexperienced dentist, however, may want to consider performing the treatment in two appointments until confidence in proper case selection has been achieved..

Vital pulp exposure. Although the routine practice of indirect pulp therapy in properly selected teeth will significantly reduce the number of direct pulp exposures encountered, all dentists who treat severe caries in children will be faced with treatment decisions related to the management of vital pulp exposures. The appropriate procedure should be selected only after a careful evaluation of the patient’s symptoms, results of diagnostic tests, and conditions at the exposure site. The health of the exposed dental pulp is sometimes difficult to determine, especially in children, and there is often lack of conformity between clinical symptoms and histopathologic condition..

SIZE OF THE EXPOSURE AND PULPAL HEMORRHAGE. The size of the exposure, the appearance of the pulp, and the amount of bleeding are valuable observations in diagnosing the condition of the primary pulp. For this reason the use of a rubber dam to isolate the tooth is extremely important; in addition, with the rubber dam the area can be kept clean and the work can be done more efficiently. The most favorable condition for vital pulp therapy is the small pinpoint exposure surrounded by sound dentin. However, a true carious exposure, even of pinpoint size, will be accompanied by inflammation of the pulp, the degree of which is usually directly related to the size of the exposure.

DENTAL HEMOGRAM. The use of the dental hemogram is not a practical diagnostic method in the routine clinical management of vital pulp exposures. However, experimental use of the dental hemogram has confirmed that a history of spontaneous pain and clinical evidence of profuse pulpal hemorrhage tend to correlate well with significant inflammation of pulpal tissue..

VITAL PULP THERAPY TECHNIQUES. For many centuries, and probably from almost the beginning of time for human beings, there has been a search for the best methods of managing pulpal disease and traumatic pulpal exposure. During the twentieth century a significant share of the total dental research effort was devoted to finding better treatments and prevention methods for pulpal problems. These efforts have generated considerable controversy and debate as proponents of specific materials and methods attempt to justify their chosen techniques. These controversies are unsettled even now in the twenty-first century, despite many impressive scientific advancements. Identifying the best formulation of ingredients and techniques to predictably produce pulpal healing remains elusive. To further complicate this issue, the predominant belief is that pulp therapies appropriate for permanent teeth may not always be equally effective in treating similar pulpal conditions in primary teeth..

It is generally agreed that the prognosis after any type of pulp therapy improves in the absence of contamination by pathogenic microorganisms. Thus biocompatible neutralization of any existing pulpal contamination and prevention of future contamination are worthy goals in vital pulp therapy. If the treatment material in direct contact with the pulp also has some inherent quality that promotes, stimulates, or accelerates a true tissue-healing response, so much the better. However, it is recognized that vital pulp tissue can recover from a variety of insults spontaneously in a favorable environment. The techniques and procedures discussed in the following pages represent the standards as we perceive them at this writing. Some go back to the time when treatment decisions were made empirically. Their effectiveness has been proved over time, if not by science, and they represent the benchmarks with which newer techniques are compared. We look forward to having more effective, biologically compatible, and scientifically sound methods in the future..

DIRECT PULP CAPPING. The pulp-capping procedure has been widely practiced for years and is still the favorite method of many dentists for treating vital pulp exposures. Although pulp capping has been condemned by some, others report that, if the teeth are carefully selected, excellent results are obtained. It is generally agreed that pulp-capping procedures should be limited to small exposures that have been produced accidentally by trauma or during cavity preparation or to true pinpoint carious exposures that are surrounded by sound dentin.

All pulp treatment procedures should be carried out under clean conditions using sterile instruments. Use of the rubber dam will help keep the pulp free of external contamination. 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. Calcium hydroxide remains the standard material for pulp capping normal vital pulp tissue. The possibility of its stimulating the repair reaction is good. A hard-setting calcium hydroxide capping material should be used. If the tooth is small, the hard-setting calcium hydroxide may also be used as the base for the restoration. Some studies have shown successful results with direct capping of exposed pulps with adhesive bonding agents, whereas others have reported pulp inflammation and unacceptable results using this technique. The use of mineral trioxide aggregate has shown promise, but further research would be helpful. Therefore the traditional practice of using calcium hydroxide can be maintained..

DIRECT PULP CAPPING. 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.