June 2018
Volume 39, Issue 6

Pulpotomy/Pulp-capping Vs Pulpectomy: The New Endodontic Treatment Conundrum?

Dr. Bahcall

When I completed my endodontic residency in 1991, the treatment demarcation for a pulpotomy and/or pulp-capping procedure versus performing a pulpectomy was fairly straightforward. Prior to this time and into the early 1990s, a pulpotomy or pulp-capping procedure was empirically thought of as a temporary treatment of the pulp. This treatment was usually performed for emergency situations and/or for caries control on a vital pulp until a pulpectomy could be scheduled. When rotary endodontic instruments came within the standard of care in the latter part of that decade, pulpectomies became the treatment of choice over pulp-capping and emergency pulpotomies on a vital pulp. This was because the clinician was now able to effectively and efficiently perform root canal treatment with rotary endodontic files as compared to using all hand-file instrumentation as previously.

Advancements in technology and materials in the field of endodontics have led to a paradigm shift in vital pulp therapy over the past 5 years. Specifically, these advancements are the clinician's ability to histologically assess a carious-involved pulp and the advent of bioceramic materials. Up to a few years ago, the prevailing thought was that if a carious lesion encroached the pulp and the pretreatment pulpal diagnosis was a normal pulp or reversible pulpitis, the entire pulp tissue was considered inflamed and would require a pulpectomy. A recent study by Ricucci et al found that clinical pulpal diagnosis of a normal pulp or reversible pulpitis had a 96.6% histological match to the actual pulp tissue in a tooth.1 This study also showed that, in this type of case scenario, pulpal inflammation was localized to the area of the caries alone and the rest of the pulp tissue was observed to be normal. Therefore, if the pretreatment pulpal diagnosis is a normal pulp or reversible pulpitis, vital pulp therapy is the treatment of choice if the pulp is exposed during caries removal; this is followed by the placement of a permanent restoration.

Introduced in recent years, bioceramic or calcium silicate-based materials are proving to be significantly better for vital pulp therapy in comparison to calcium hydroxide. Bioceramics are biocompatible, nontoxic, and nonshrinking, and are usually stable within a biological environment. In a randomized clinical trial, Hilton et al reported that mineral trioxide aggregate (MTA), a bioceramic material, performed significantly better than calcium hydroxide as a direct pulp-capping agent.2

The clinical use of bioceramics has recently even been shown to be effective on teeth with a pulpal diagnosis of irreversible pulpitis. In a study, Taha et al reported that placement of MTA over the pulp after a partial pulpotomy in mature adult teeth that were clinically diagnosed with irreversible pulpitis had a good success rate over a 2-year follow-up.3 They also noted that more than half of the calcium hydroxide cases failed within 2 years.

Dr. Alex

Indeed, a paradigm shift is occurring regarding materials dentists are using for vital pulp therapy. For example, calcium hydroxide traditionally has been considered the "gold standard" and the most commonly used material for direct pulp-capping procedures. Although successful clinical outcomes are achievable with calcium hydroxide pulp caps (at least sometimes), this material also has significant disadvantages, including lack of innate adhesive and sealing abilities, poor physical properties, and dissolution over time.4  Long-term clinical studies show success rates with calcium hydroxide pulp caps on carious exposures to be highly variable, generally unpredictable, and often unsuccessful.5

In the early 1990s the pioneering endodontist, academician, and researcher Dr. Mahmoud Torabinejad and colleagues developed an MTA compound that was essentially a modified Portland cement. In terms of direct pulp-capping procedures, there is a growing body of scientific evidence, including controlled clinical studies, that has found MTA typically has better clinical outcomes and histologic responses than calcium hydroxide when both are compared head to head in direct pulp-capping studies.2,6-9

While studies indicate MTA is a viable, and perhaps better, alternative than calcium hydroxide for direct pulp-capping procedures, traditional powder/liquid formulations of MTA have significant drawbacks and are not used in most general dentist offices. For one thing, traditional powder/liquid formulations of MTA are not especially user friendly, require very precise mixing, and can cause tooth discoloration. Moreover, manipulation and placement can be challenging. Additionally, the long setting times (2 to 5 hours) can be a significant problem with traditional MTA formulations. Hydration accelerators, such as citric acid, lactic acid, calcium chloride, and calcium lactate gluconate, have been added to some modified MTA formulations (eg, Biodentine®, Septodont, septodontusa.com). This, along with incorporation of the powder and liquid components into capsules that can be triturated and the manipulation of particle sizes and powder/liquid ratios, along with other modifications, has significantly decreased the setting time of some MTA formulations to 10 to 15 minutes, which is still a long period of time but much more clinically manageable.

Though shorter than with traditional formulations, the 10- to 15-minute setting time of some MTA-based materials can nevertheless be problematic to clinicians. MTA-based resin-modified materials that set on demand via light polymerization (eg, TheraCal LC®, BISCO, bisco.com) may offer an attractive alternative in this regard. The ability to cure quickly via light polymerization offers a significant clinical advantage. The question regarding such a hybrid product is whether the incorporation of light-curable resin components and chemistry into an MTA matrix compromises the bioactive capabilities and desirable properties of the MTA. While there are promising studies and anecdotal reports of clinical success using light-cured MTA/resin hybrid products, caution is urged before unequivocal endorsement can be made, and further research is warranted. I recently published an article in Compendium that comprehensively discusses the use of light-cured MTA/resin hybrid materials as direct pulp-capping agents.10

The ultimate goals of any vital pulp-capping procedure should be to manage bacteria, arrest any residual caries progression, stimulate pulp cells to form new dentin, and provide a biocompatible and durable seal that protects the pulp complex from bacteria and noxious agents. Of course, the success of both direct and indirect pulp-capping procedures is contingent on the health and vitality of the pulp complex to begin with. Teeth that have a history of unprovoked spontaneous pain, necrotic or partially necrotic pulps, radiographic pathology, or excessive hyperemia on direct pulp exposure due to irreversible pulpitis have a poor prognosis and often require endodontic intervention or extraction at some point.

Dr. Trope

We have known for decades that when a pulp has a carious exposure, the tissue adjacent to the exposure is necrotic, followed by a localized inflamed pulp, and the rest of the pulp is normal.11 The classic monkey study by Tronstad andMjör12 and multiple clinical studies performed in the 1960s and 1970s concluded that the inflamed pulp (carious exposure) could not be predictably treated with a pulp-capping procedure.5

In the 1960s and 1970s when those studies where performed, calcium hydroxide was the capping agent used and amalgam was used for the coronal seal restoration. While calcium hydroxide works predictably when placed on the pulp, it washes out in the presence of tissue fluid.13

It is now clear that what was happening in those cases decades ago was that the amalgam leaked and because calcium hydroxide is a soluble medicament it would wash out, leaving the pulp at the mercy of constant microbial challenge. Depending on timing, some pulps managed to create a hard tissue barrier in time to defend against microbial challenge, but too many became necrotic.

Today clinicians have the advantage of bioceramic products that are hydrophilic in nature. They produce calcium hydroxide during the hydration process and are, thus, bioactive when unset. When set, they are biostable, expand slightly, and produce an excellent seal. Thus, they provide a high pH like calcium hydroxide but do not wash out. As stated by Dr. Bahcall, there is mounting evidence that capping the inflamed pulp can be a highly successful and predictable procedure.

MTA was the first pure bioceramic on the market and is an excellent material. However, it discolors over time and should be avoided in vital pulp therapy because of esthetic considerations. Biodentine and Endosequence Fast Set Putty (Brasseler, brasselerusadental.com) are second-generation pure bioceramic materials that perform equally to MTA but do not discolor. I would avoid the resin-based "biological" products. Resin generally shrinks on setting, while bioceramics expand slightly. Thus, many of these bioactive products do not perform as the labels suggest. As long as pure bioceramics are available, they would be my preference.

About the Authors

James Bahcall, DMD, MS
Clinical Associate Professor, Department of Endodontics, University of Illinois-Chicago School of Dentistry, Chicago, Illinois; Diplomate, American Board of Endodontics

Gary Alex, DMD
Private Practice, Huntington, New York; Accredited Member, American Academy of Cosmetic Dentistry; Member, International Association for Dental Research

Martin Trope, DMD
Clinical Professor, Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Private Practice, Philadelphia, Pennsylvania; Diplomate, American Board of Endodontics

References

1. Riccucci D, Loghin S, Siqueira JF Jr. Correlation between clinical and histologic pulp diagnoses. J Endod. 2014;40(12):1932-1939.

2. Hilton TJ, Ferracane JL, Manci L; Northwest Practice-based Research Collaborative in Evidence-based Dentistry (NWP). Comparison of CaOH with MTA for direct pulp capping: a PBRN randomized clinical trial. J Dent Res. 2013;92(7 suppl):16S-22S.

3. Taha NA, Khazali MA. Partial pulpotomy in mature permanent teeth with clinical signs indicative of irreversible pulpitis: a randomized clinical trial. J Endod. 2017;43(9):1417-1421.

4. Cox CF, Hafez AA, Akimoto N, et al. Biological basis for clinical success: pulp protection and the tooth-restoration interface. Pract Periodontics Aesthet Dent. 1999;11(7):819-826.

5. Barthel CR, Rosenkranz B, Leuenberg A, Roulet JF. Pulp capping of carious exposures: treatment outcome after 5 and 10 years: a retrospective study. J Endod. 2000;26(9):525-528.

6. Leye Benoist F, Gaye Ndiaye F, Kane AW, et al. Evaluation of mineral trioxide aggregate (MTA) versus calcium hydroxide cement (Dycal®) in the formation of a dentine bridge: a randomised controlled trial. Int Dent J. 2012;62(1):33-39.

7. Mente J, Hufnagel S, Leo M, et al. Treatment outcome of mineral trioxide aggregate or calcium hydroxide direct pulp capping: long-term results. J Endod. 2014;40(11):1746-1751.

8. Dammaschke T, Wolff P, Sagheri D, et al. Mineral trioxide aggregate for direct pulp capping: a histologic comparison with calcium hydroxide in rat molars. Quintessence Int. 2010;41(2):e20-e30.

9. Zhu C, Ju B, Ni R. Clinical outcome of direct pulp capping with MTA or calcium hydroxide: a systematic review and meta-analysis. Int J Clin Exp Med. 2015;8(10):17055-17060.

10. Alex G. Direct and indirect pulp capping: a brief history, material innovations, and clinical case report. Compend Contin Educ Dent. 2018;
39(3):182-189.

11. Van Hassel HJ. Physiology of the human dental pulp. Oral Surg Oral Med Oral Pathol. 1971;32(1):126-134.

12. Tronstad L, Mjör IA. Capping of the inflamed pulp. Oral Surg Oral Med Oral Pathol. 1972;34(3):477-485.

13. Schröder U, Granath LE. Early reaction of intact human teeth to calcium hydroxide following experimental pulpotomy and its significance to the development of hard tissue barrier. Odontol Revy. 1971;22(4):379-395.

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