Novel Medicaments for Pulpotomies in Primary Teeth

A primary tooth pulpotomy involves amputation of coronal pulp tissue with inflammatory or degenerative changes resulting from a carious, traumatic or mechanical exposure, and preserving the remaining vital tissue in the root canal. The goal is to maintain the tooth in the dental arch until exfoliation. Following extirpation of the diseased pulpal tissue, hemostasis of the radicular pulp is accomplished and then treated with a medicament. Numerous medicaments have been used for pulpotomies, including calcium hydroxide, ferric sulfate, glutaraldehyde, sodium hypochlorite, mineral trioxide aggregate (MTA), and formocresol.¹ In recent years, new materials have been introduced that are designed to overcome some of the limitations of traditional pulpotomy medicaments. This paper will review the clinical use and advantages of these novel products in pediatric dentistry.

For decades, formocresol has been considered the gold standard to which other materials are compared; it is one of the most frequently used vital pulp therapy materials for primary teeth. It is a bactericidal agent with reported clinical and radiographic success rates of 70% to 97%.² Yet even with such high success rates, concerns over formocresol have been raised. One of its main components is formaldehyde, which has been identified as a hazardous substance.³ Histological studies of formocresol use in pulpotomies have shown that it may result in chronic inflammation and necrotic tissue instead of preserving vital pulp tissue.^4,5 There have been reports and speculation on possible cytotoxic and mutagenic consequences with the use of formocresol. However, Milnes³ examined research into formocresol and formaldehyde metabolism, pharmacokinetics and carcinogenicity, and concluded that when formocresol is used judiciously for pulpotomies it is highly unlikely to be genotoxic, immunotoxic or pose a cancer risk in children. 

Despite these findings, clinicians and parents/​​caregivers may have concerns about formocresol and not be receptive to its use in children. Some countries have even banned its use. To address these concerns, newer materials for pulpotomies derived from tricalcium/​​dicalcium (tri/​​dicalcium) silicate-based cements have been introduced that are biocompatible, bioactive and nontoxic. These products are free of formocresol, yet have been equally successful in pulpotomy treatment of primary teeth. 

Beginning in the 1990s, MTA was the first of these tri/​​dicalcium silicate-based products to be extensively used in dentistry. Its original formulation was a modified Portland cement ceramic powder composed of tricalcium silicate, dicalcium silicate, tricalcium aluminate, tetracalcium aluminoferrite, bismuth oxide, and minor amounts of magnesia, potassia, soda and sulfates.⁶ Featuring excellent sealing ability, MTA can induce hard tissue formation in pulp tissue while maintaining the integrity of the tissue. In addition, it is less cytotoxic than other pulpal materials^4,6,7 and has demonstrated long-term success as a medicament for pulpotomies.^1,2,4,6 The disadvantages are its cost, prolonged setting time, high solubility prior to setting, difficult handling and manipulation, and tendency to cause a gray discoloration of remaining crown structure.^4,6,7

A guideline panel convened by the American Academy of Pediatric Dentistry formulated evidence-based recommendations on the use of vital pulp therapies in primary teeth and strongly recommended both the use of MTA and formocresol as pulpal medicaments in pulpotomies. This conclusion was based on moderate-quality evidence.⁸ Despite this recommendation, several new tri/​​dicalcium silicate-based materials have been introduced in recent years that reportedly overcome the disadvantages of formocresol and traditional MTA. Some of these products are premixed, allowing for rapid placement of the material — which is advantageous when working with children who have trouble sitting still, have short attentions spans, or are less than cooperative. As noted, this paper will review the clinical use and advantages of these novel products in pediatric dentistry.

REFORMULATED MINERAL. TRIOXIDE AGGREGATE PRODUCTS

For clinicians who prefer using MTA for pulpotomies, numerous manufacturers have fine-tuned the original formulation by adjusting the amounts of the components or substituting components outright. Depending on the adjustments, these newer MTA products can offer improved handling, greater radiopacity, increased strength and decreased setting time — and are often less expensive than original MTA formulas. Some of these reformulated materials are nonstaining. Currently, more than 20 MTA-type products are commercially available worldwide, providing the clinician with many options.⁶ 

A recent addition to the bioactive/​​biocompatible pulpotomy materials is an MTA-containing product that is formulated as a putty. This putty is a premixed MTA (tri/​​dicalcium silicate powder in an organic medium) delivered via a syringe and thus does not require hand mixing. The syringe also gives the clinician the ability to dispense the exact amount of material needed for the procedure and thus reduces waste. Unlike regular MTA, it does not cause discoloration of remaining tooth structure. It is dimensionally stable, with zero shrinkage and minimal expansion, and has a very high radiopacity.⁹ This product has been reported to have a longer shelf life than a similar MTA putty when both are exposed to ambient air, and, from an in vitro cytotoxicity perspective, is significantly more biocompatible than the other putty.¹⁰ In addition to use in pulpotomies, the MTA putty can be utilized in apexification and apexogenesis procedures, perforation repairs, obturation, root end filling, as a liner or base, and as a pulp capping agent (both direct and indirect).⁹ 

During a pulpotomy procedure, the putty is easily injected into the pulp chamber with a supplied plastic applicator tip. An alternative is to express the material onto a glass slab or mixing pad and roll it into a ball or cylindrical shape and apply it to the treatment site with a plastic instrument, condenser or a similar instrument of choice (Figure 1). A 1.5-mm thickness of the material is recommended. Excess product can be removed with a cotton pellet slightly moistened with sterile water or saline. The manufacturer claims the material resists washout after placement.⁹ However, based on clinical experience, the authors’ opinion is that if the practitioner is going to restore the tooth with a stainless steel crown and the prep remains to be completed after placement of the putty (Figure 2), the material should be covered with a light curable composite, glass ionomer, resin modified glass ionomer, compomer, or zinc oxide and eugenol to prevent washout during the crown preparation. 

TRI/​​DICALCIUM SILICATE DENTIN REPLACEMENT MATERIAL

Another of the novel modified tri/​​dicalcium silicates that has proven effective in primary teeth pulpotomies is also marketed as a dentin replacement restorative material because its compression strength is similar to natural dentin.^11,12 The material forms both an intrinsic seal and a seal at the material-dentin interface that reduces microleakage.^11,13 Because it stimulates pulpal healing processes, it is bioactive.¹³ Its advantages over MTA include a much shorter setting time and less potential for tooth discoloration.¹⁴ It is supplied as a powder/​​liquid system. The powder is composed of tricalcium silicate, calcium carbonate, zirconium oxide, dicalcium silicate, calcium oxide and iron oxide, all of which are contained within a capsule.¹⁵ The material is mixed for 30 seconds using a standard amalgamator after adding five drops of the supplied liquid (containing calcium chloride and hydrosoluble polymer) to the capsule of powder. Once hemostasis of the residual radicular pulp is achieved during the pulpotomy procedure, this tricalcium silicate can be bulk filled into the pulp chamber. It requires no bonding agent for retention.¹¹

This tricalcium silicate dentin replacement has well-documented clinical outcomes as a pulpal medicament in primary molar pulpotomies. A randomized clinical trial compared the success of this material and MTA primary molar pulpotomies; the authors concluded the two materials did not differ significantly in combined clinical and radiographic success after 24 months.¹⁴ A more recent study of primary molar pulpotomies using this product had favorable results after 30 months, with a cumulative clinical survival rate of 93.7% and an 85.6% radiographic success rate.¹³ Another randomized clinical control trial concluded this tricalcium silicate material demonstrated a higher (though not statistically significant) success rate than formocresol in primary molar pulpotomies followed for up to four years.¹⁵

RESIN-MODIFIED CALCIUM SILICATE

Another new product is a biocompatible, dual-cured resin modified synthetic Portland cement calcium silicate that is primarily indicated for pulpotomies, but can also be used as a liner or base and as a pulp capping agent. The material consists of a base and catalyst that is dispensed from a double-barrel syringe. After obtaining pulpal hemostasis during the pulpotomy, the product is dispensed from the syringe through use of a dispensing tip that creates a uniform mix, allowing for direct placement into the pulp chamber. The clinician should apply enough material to allow good adaptation of the silicate to the cavity walls and margins, and light cure for 10 seconds. The desired adhesive, base and/​​or restoration of choice is then placed. Because this product is a dual-cured material having both chemical- and light-cure capabilities, it can be used in one placement as a bulk fill of the entire pulp chamber.¹⁶ With this feature (and especially since the product does not require hand mixing), valuable chairtime is saved. 

The base component of this product consists of SG-mix cement, bisphenol A-glycidyl methacrylate (BisGMA) and barium zirconate.¹⁷ The catalyst is comprised of BisGMA, barium zirconate, ytterbium fluoride and a proprietary initiator.¹⁸ This resin modified calcium silicate offers the unique advantages of alkaline pH and radiopacity, and is moisture tolerant. It differs from MTA because of its unique calcium-releasing hydrophilic resin.¹⁶ At this time, a lack of long-term clinical studies exists for this resin-modified calcium silicate, but anecdotal accounts report good success with the use of this product as a medicament for pulpotomies in primary teeth.^19,20

CONCLUSION 

It should be noted that for best results when performing a pulpotomy on a primary tooth, consideration should be given to changing the procedure from a pulpotomy to a pulpectomy, or extracting the tooth if pulpal hemorrhage cannot be controlled prior to the placement of any medicament. This is because prolonged bleeding is often indicative of the presence of inflammation in the remaining radicular tissue.¹

In summary, the introduction of novel bioactive tri/​​dicalcium silicate-based medicaments gives the clinician several promising alternatives to the use of formocresol or MTA in primary tooth pulpotomies. Some of these products are premixed and can be bulk filled when applied, which shortens the chairtime needed — a characteristic that is valuable when rendering care to young and/​​or apprehensive children. The success of these products in pediatric dentistry has led many to predict that some of these materials may soon replace formocresol and ferric sulfate as the go-to medicaments for pulpotomies in primary teeth.⁶ However, further clinical studies of the long-term performance and efficacy of these novel materials are needed.

KEY TAKEAWAYS

• In recent years, new materials have been introduced that are designed to overcome some of the limitations of traditional pulpotomy medicaments for primary teeth.
• These newer materials are derived from tricalcium/dicalcium silicate-based cements and are biocompatible, bioactive and nontoxic.
• The alternative products are free of formocresol, yet have been equally successful in pulpotomy treatment of primary teeth.
• For clinicians who prefer using mineral trioxide aggregate (MTA) for pulpotomies, numerous manufacturers have fine-tuned the original formulation by adjusting the amounts of the components or substituting components outright.
• Depending on the adjustments, these newer MTA products can offer improved handling, greater radiopacity, increased strength and decreased setting time — and are often less expensive than original MTA formulations.
• In summary, the introduction of novel bioactive tricalcium/dicalcium silicate-based medicaments offers clinicians several promising alternatives to the use of formocresol or MTA in primary tooth pulpotomies.

ACKNOWLEDGEMENT: The authors thank Mary Carter, PhD, Writing Center coordinator at the University of Oklahoma Health Sciences Center for reviewing this manuscript.

The authors have no conflicts of interest to disclose.

REFERENCES

1. American Academy of Pediatric Dentistry. Pulp therapy in primary and immature permanent teeth. The Reference Manual of Pediatric Dentistry. Chicago: American Academy of Pediatric Dentistry; 2020:384–392.
2. Fuks A, Kupietzky A, Guelmann M. Pulp therapy for the primary dentition. In: Nowak AJ, Christensen JR, Mabry TR, Townsend JA, Wells MH, eds. Pediatric Dentistry: Infancy Through Adolescence. 6th ed. St. Louis: Elsevier; 2019:329–351.
3. Milnes AR. Is formocresol obsolete? A fresh look at the evidence concerning safety issues. J Endod. 2008;34:S40–S46.
4. Chandrashekhar S, Shashidhar J. Formocresol, still a controversial material for pulpotomy: A critical literature review. J Res Dent. 2014;2:114–124.
5. Rolling I, Lambjerg-Hansen H. Pulp condition of successfully formocresol-treated primary molars. Scand J Dent Res. 1978;86:267–272.
6. Primus CM, Tay FR, Niu L. Bioactive ​tri/​​dicalcium silicate cements for treatment of pulpal and periapical tissues. Acta Biomater. 2019;96:35–54.
7. Abukabbos H, Tomar S, Guelmann M. Cost estimates for bioactive cement pulpotomies and crowns in primary molars. Pediatr Dent. 2018;40:51–55.
8. Dhar V, Marghalani AA, Crystal YO, et al. Use of vital pulp therapies in primary teeth with deep carious lesions. Pediatr Dent. 2017;39:146–159.
9. NuSmile NeoPutty FAQs. Available at: www.nusmile.com/​​NeoPutty/​​Technical-Support. Accessed May 11, 2021.
10. Sun Q, Meng M, Steed JN, et al. Manoeuvrability and biocompatibility of endodontic tricalcium silicate-based putties. J Dent. 2021;104:103530.
11. Bachoo IK, Seymour D, Brunton P. A biocompatible and bioactive replacement for dentine: is this a reality? The properties and uses of a novel calcium-based cement. Br Dent J. 2013;214:E5.
12. Butt N, Talwar S, Chaudhry S, Nawal RR, Yadav S, Bali A. Comparison of physical and mechanical properties of mineral trioxide aggregate and Biodentine. Indian J Dent Res. 2014;25:692–697.
13. Wong BJ, Fu E, Mathu-Muju KR. Thirty-month outcomes of Biodentine pulpotomies in primary molars: a retrospective review. Pediatr Dent. 2020;42:293–299.
14. Bani M, Aktas N, Cinar C, Odabas ME. The clinical and radiographic success of primary molar pulpotomy using Biodentine and mineral trioxide aggregate: a 24-month randomized clinical trial. Pediatr Dent. 2017;39:284–288.
15. Rubanenko M, Petel R, Tickotsky N, et al. A randomized controlled clinical trial comparing tricalcium silicate and formocresol pulpotomies followed for two to four years. Pediatr Dent. 2019;41:446–450.TheraCal PT product information. Available at: www.bisco.com/​​theracal-pt-/​​. Accessed May 11, 2021.
16. TheraCal PT Base Safety Data Sheet. Issue date: 3-6-2020, Version: 1.0. Available at: www.bisco.com/​​documents/​​?CategoryId=10&pg=2. Accessed May 11, 2021.
17. TheraCal PT Catalyst Safety Data Sheet. Issue date: 3-6-2020, Version: 1.0. Available at: www.bisco.com/​​documents/​​?CategoryId=10&pg=2. Accessed May 11, 2021.
18. Dental Advisor. Clinical Evaluation of TheraCal PT. Available at: www.dentaladvisor.com/​​evaluations/​​theracal-pt/​​. Accessed May 11, 2021.
19. Hernandez Cabanillas JC: Pulpotomy in a primary molar using a calcium silicate material. DPS. 2020;14(4):32–33.

From Decisions in Dentistry. June 2021;7(6)22-24.