Question: What is your opinion about direct pulp capping as an option to retain teeth?
By Howard E. Strassler, DMD | Allen Ali Nasseh, DDS | Gregori M. Kurtzman, DDS
Pulp capping of vital permanent teeth with a mature apex is a controversial subject. Much of the dental literature on decision-making for direct pulp capping is not very current and is based upon the orientation of the author—restorative dentist or endodontist. There are many factors that can guide the clinician in making the decision to pulp cap or not. First and foremost, the type of pulp exposure plays a critical role in the potential for success—is it a carious exposure or is it a mechanical or trauma-injury pulp exposure. Combine the clinical situation with other information including past history of pain, radiographic evaluation, pulp vitality testing data, what restoration is treatment planned for the tooth, will heroic measures be necessary to salvage the tooth (endodontic treatment, crown lengthening, crown vs an implant) and financial considerations, and the waters can get muddied.
The goal is to keep the tooth. Pulp capping of vital mechanical and traumatic exposure of the pulp if the field is kept aseptic has a reasonable chance of success. For caries-exposed vital pulps the challenge is different—there is already inflammation of the pulp. It is difficult to get a consensus on decision-making for direct pulp capping for carious teeth. Maintaining pulp vitality is the goal for a permanent tooth with deep caries and the potential for pulp exposure that is vital and asymptomatic with no radiographic evidence of periapical infection. One does not need to remove all the caries in the preparation adjacent to the pulp. Certainly, all lateral walls need to be prepared to remove carious dentin. The consideration is to perform an indirect pulp cap. If there is a carious exposure, endodontic treatment should be recommended and certainly if the tooth is treatment planned for an indirect laboratory-fabricated restoration, I strongly recommend endodontic treatment.
If the patient for financial reasons cannot afford endodontic therapy, consideration should be given for direct pulp capping to retain the tooth. It is critical to monitor the pulp on recall radiographically and with vitality tests.
Contrary to common belief, vital pulp therapy is a viable option and enjoys a relatively high success rate when strict aseptic protocol is combined with proper case selection. The variability in success rates reported in the literatures is clearly indicative of the importance of case selection in deciding whether vital pulp therapy or root canal therapy is the correct decision for a given case.
Before I discuss the indications for vital pulp therapy, I’d like to emphasize the importance of all decision-making to have the aim of avoiding pulpal necrosis as its ultimate goal. Necrosis should be avoided because nonsurgical endodontic therapy in necrotic pulps with periapical lesions has a lower success rate compared to vital/inflamed pulps. If the potential for necrosis is high, vital pulp therapy should be substituted with prophylactic root canal therapy for the highest possible treatment success.
So, what are some of the indications for vital pulp therapy? Basically, young pulps, where a non-carious, mechanical exposure of the roof of the chamber has occurred under completely aseptic conditions (rubber dam isolation), and where the tooth will not have a high strategic importance (eg, will not serve as an abutment to a fixed or removable prosthesis). In such cases, vital pulp therapy will have a good success rate.
If we worked under complete sterility, vital pulp therapy would work 100% of the time. However, this is often unavoidable as the cause of exposure is most commonly caries. In situations, however, where all caries has been removed long before exposure and the pulp was historically asymptomatic, and where treatment was performed under aseptic conditions (proper rubber-dam isolation,) vital pulp therapy may be attempted. While Ca(OH)2 formulations were used for the longest time for this purpose, with the rise of bioceramics in endodontics, these materials appear very promising as they are hydrophilic, disinfecting, and set with a non-resorbable final set with adequate compressive strength. Bioceramic root repair materials may be used as a liner to directly seal the exposed site followed by placement of a glass-ionomer base and the final restoration.
Patient age when the exposure occurs affects the success of direct pulp capping. The highest success is reported in patients aged 10 to 19 years as these teeth tend to have the most vital pulpal tissue. Another factor that has been reported is location of the tooth, with central incisors showing the highest success and success decreasing in a posterior direction.
Mechanical exposures have a significantly higher success rate than those exposures caused by caries. This relates to bacterial penetration and duration of the bacterial exposure of the pulpal tissue. With this in mind, when an exposure is related to caries, immediate progression to endodontic therapy appears to be the best treatment. Yet, when this is related to mechanical exposure (eg, traumatic fracture with exposure or nicking a pulp horn during cavity preparation) direct pulp capping has been proven to be a viable treatment with a good long-term prognosis. This success relates to placement of a bonded restoration sealing the margins surrounding the exposure.
But success really relates to the vitality of the tooth in question. Teeth that test vital and have no clinical symptoms or radiographic apical widening will present with a better prognosis after direct pulp capping. Whereas teeth that the patient has reported to be sensitive prior to treatment, especially over time, should be treated endodontically as pulp capping has a poor prognosis.
Disinfection of the exposure may help influence success by eliminating bacteria at the exposure. Using a laser to control hemorrhage and decrease bacteria at the site may be prudent in treating these exposures before direct pulp capping. Calcium hydroxide has a long history for use in both direct and indirect pulp capping, but due to its solubility over time and its non-adhesive nature, using a material that sets hard and is insoluble and adhesive is more prudent. The newer self-etch resins show promise in this area, as they provide good adhesion to the surrounding dentin, create a good seal around the exposure, and do not require the use of an acid-etching gel.
About the Authors
Howard E. Strassler, DMD | Dr. Strassler is a professor and director of operative dentistry in the Department of Endodontics, Prosthodontics and Operative Dentistry at the University of Maryland Dental School.
Ali Allen Nasseh, DDS | Dr. Nasseh is a clinical instructor in the Department of Restorative Dentistry and Biomaterial Sciences of Harvard School of Dental Medicine, and has a private practice in Boston, Massachusetts.
Gregori M. Kurtzman, DDS | Dr. Kurtzman is in private general practice in Silver Spring, Maryland.