December 1, 2012
by Howard E. Strassler, DMD and Robert Levin, DDS
Vital pulp therapy is a critical aspect of all restorative treatment. The goal during the placement of any restoration, whether it be a direct placement composite resin or amalgam restoration or a full coverage crown, is to best maintain a vital and healthy pulp. This is accomplished with good clinical practices of caries removal, treatment of a traumatic injury to a tooth, and judicious use of air-water spray when preparing a tooth with a high speed handpiece, among others. There are times when vital pulp therapy includes those clinical situations where the pulp is at risk due to trauma, caries, or the placement and replacement of restorations over the restorative cycle of the life of a restoration. The focus of this paper will be on vital pulp therapy as it relates to pulp capping.
There is generally little agreement on the treatment of a carious exposed pulp for a vital permanent tooth1,2 (Fig. 1). A recent systematic review of vital pulp therapy in vital permanent teeth with cariously exposed pulps reviewed success rates of direct pulp capping.3 In this review the success rate of direct pulp capping was reported as >6 months-1 year, 87.5%; >1-2 years, 95.4%; >2-3 years, 87.7% and >3 years, 72.9%. Partial and full pulpotomy sustained high success rates up to more than three years (partial pulpotomy, 99.4%; full pulpotomy, 99.3%). The conclusion of this review was that vital permanent teeth with carious pulpal exposures can be treated successfully with vital pulp therapy. A retrospective study of direct pulp-capping with calcium hydroxide by dental students evaluating radiographic outcomes reviewed cases that were pulp-capped at least three years previously both from mechanical pulpal exposures and carious exposures.4 The results indicated a success rate for mechanical exposures of 92.2% and for carious exposed pulps, 33.3%. Larger preparations had less success, Class II (56.1%) than Class I (83.8%).
Before a clinician considers the placement of a direct pulp cap, the patient must understand that in most clinical situations a carious exposure should be treated with endodontic therapy (Fig. 1). Under the most favorable circumstances traditional root canal treatment has a success rate of up to 95%.5 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, i.e., carious exposures are less successful than a mechanical or trauma injury exposing the pulp. For each clinical situation clinical data should be collected and evaluated when making the decision to pulp cap. These data include past history of pain, radiographic evaluation, pulp vitality testing data, which type of restoration is treatment planned for the tooth, if adjunctive measures will be necessary to salvage the tooth (e.g., endodontic treatment, crown lengthening, crown vs. an implant), and financial considerations. The patient needs to understand what is the optimal treatment for pulp exposed teeth as compared to the alternatives. Teeth with a history of pain and a diagnosis of irreversible pulpitis should be excluded from consideration for a direct pulp of a carious exposure. The goal is to keep the tooth. Pulp capping of vital mechanical and traumatic exposure of the pulp if the field is kept aseptic can have a reasonable chance of success. To these authors, the choice of direct pulp capping of carious exposures in vital, asymptomatic permanent teeth and restoring a tooth is a better choice than extraction.
Today finances are a considerable driving force for some of our patient’s treatment decisions. If the patient for financial reasons cannot afford endodontic therapy, consideration should be given for vital pulp therapy to retain the tooth. Vital pulp therapy can include direct pulp capping or performing a pulpotomy covering the root canal orifices with bioactive pulp capping materials. Success with vital pulp therapy is dependent on dentin-pulp engineering strategies using materials that have progenitor cell potentials and also interact with other non-progenitor “supportive” cells.6 Under severe caries lesions, progenitor cells may be activated by growth factors released after the acidic dissolution of carious dentin.6 These strategies can lead to dentin regeneration.
Utilizing similar chemistry to that of MTA, a bioactive tricalcium silicate (Biodentine, Septodont) was introduced for use in vital pulp therapy for direct pulp capping, pulpotomy, and indirect pulp capping. Recent studies evaluating a medical grade calcium silicate based material (Biodentine, Septodont) and techniques for vital pulp therapy have been very positive. As part of the chemical setting reaction of Biodentine calcium hydroxide is formed.7 Biodentine has demonstrated bioactivity and formation of apatite.8 Other research has described the ability of the tricalcium silicate-based cement to induce reparative dentin synthesis by modulating pulp cells to secrete TGF-ß1 and stimulate dental pulp mineralization.9 Bioactive tricalcium silicate has several advantages over calcium hydroxide and mineral trioxide aggregates (MTA). The commercialized tricalcium silicate is different from the usual dental calcium silicate “Portland Cement” materials. The manufacturing process of the active biosilicate technology eliminates the metal impurities seen in the “Portland Cement” calcium silicates. The setting reaction is a hydration of tricalcium silicate which produces a calcium silicate gel and a calcium hydroxide. In contact with phosphate ions, it creates precipitates that resemble hydroxyapatite.10 These precipitates from MTA and tricalcium silicate can be incorporated into root canal dentin.11 A comparison of the calcium and silica uptake of adjacent root canals treated with MTA versus tricalcium silicate demonstrated a greater uptake of the tricalcium silicate.11 Using confocal microscopy there was an increase in the carbonate content of interfacial dentin, which suggested intertubular diffusion and mineral tags of Biodentine hydration products creating a hybrid zone.12 Burgess and coworkers characterized this hybrid zone as being microleakage free.13
Histologically, the bioactive tricalcium silicate demonstrated the ability to induce odontoblast differentiation from pulp progenitor cells. The resulting mineralized matrix had the molecular characteristics of dentin.6 An evaluation comparing the biocompatibility of the tricalcium silicate with MTA and Dycal demonstrated that the Biodentine was equivalent to MTA (Dentsply) and more biocompatible than Dycal (Dentsply-Caulk).14 A clinical evaluation over 6-35 months of Biodentine as a base and for pulp capping demonstrated both biocompatibility and longevity.15
Clinical evaluations have demonstrated success rates with pulp capping of carious exposed teeth using calcium hydroxide, MTA, and tricalcium silicate of between 72.9% to 98%.3,16-18 Younger patients have higher success rates.16 MTA has extended working and setting times.19,20 Further, Biodentine is faster setting than other calcium silicate cements, allowing it to be used as a liner and as a dentin substitute base under definitive restorative materials.13 Sluyk and coworkers reported that MTA required a setting time of 72 hours to resist displacement and dislodgement from dentin walls of a preparation.20 Within 35 minutes from placement MTA demonstrated insignificant setting and within 24 hours it had only 23% of the compressive strength of the material at 28 days.13 It has been recommended that before restoring the tooth MTA should be covered with a light cured glass ionomer liner after placement because of MTA’s extended setting time.21 An evaluation comparing Biodentine to two commercially available liner/base materials, Fuji IX (GC America) and VitreBond (3M-ESPE) in their resistance to compressive deflection when covered with a restorative composite resin, demonstrated that after a 10 minute setting time all three materials tested s
upported the composite resin at a clinically relevant load.22,23 Biodentine is faster setting than other calcium silicate cements allowing it to be used as a liner and a dentin substitute base under definitive restorative materials.
In recent years, there has been a greater acceptance of practice-based research studies.24,25 These practice-based evaluations have undertaken short-term clinical studies to solve problems that are encountered in daily clinical practice.26 Practice-based research networks have been shown to strengthen the professional knowledge base by applying principles of good clinical practice, creating a resource for training practitioners and improving the scope of care.27 A practice based study by the second author of this paper evaluated the use of a tricalcium silicate material (Biodentine) as vital pulp therapy in pulp capping of carious teeth with recalls up to two years (Figs. 2 & 3); at the last recall 46 of 48 teeth were still vital and pain-free. Critical to clinical success and as part of the protocol, teeth that were asymptomatic vital permanent teeth with radiographic evidence of deep caries in proximity to the pulp, with no radiographic evidence of periapical pathology and no past history of pain, were selected for inclusion in this study.
A 24 year patient presented with a deep carious lesion on the facial surface of the mandibular canine. There was no past history of pain, the tooth pulp tested vital to EPT and cold test with no lingering pain. The tooth was negative to percussion and palpation. There was no radiographic evidence of periapical pathology (Fig. 4). During caries removal with a spoon excavator hand instrument, a small carious pulpal exposure was visualized (Fig. 5). Since there was no history of pain and the pulp was vital, the decision was made to do a direct pulp cap with a tricalcium silicate material (Biodentine). Following the clinical protocol described by Bogen and coworkers,16 after caries removal, bleeding of the vital pulp was controlled using a cotton pellet wet with sodium hypochlorite placing pressure on the pulp exposure. When the bleeding was controlled the preparation was blotted dry with a dry cotton pellet. The tricalcium silicate was mixed as per the manufacturer’s directions. The mixed material was putty like in consistency (Fig. 6). The Biodentine was dispensed to a mixing pad and was applied to the cavity preparation using an amalgam carrier. The cavity preparation was bulk-filled and the material was adapted and contoured using a plastic filling instrument. The material was allowed to set for 10 minutes. Excess restorative material was contoured with disks (Fig. 7). Currently based upon the most recent data34,37,38 the tricalcium silicate can be placed as a liner-base, allowed to set for five minutes and then the preparation restored with composite resin.
One month after placement, the tooth was evaluated for pulp vitality and tested normal to cold and EPT. The tooth was negative to percussion and palpation and had been asymptomatic. The restorative material was removed leaving a thin liner to not disturb the pulp cap and the adjacent premolar was also prepared (Fig. 8). The preparations were then restored with an etch and rinse adhesive and nano-hybrid composite resin (Fig. 9).
For caries exposed vital pulps where there is already inflammation of the pulp, it is difficult to get a consensus on decision-making for direct pulp capping. The goal for a permanent tooth with deep caries and the potential for pulp exposure that is vital, asymptomatic with no radiographic evidence of periapical infection is to maintain pulp vitality. An indirect pulp cap is preferable. For a tooth with the criteria of a vital pulp (no history of spontaneous pain, no periapical radiolucencies and normal responses to percussion and palpation), tricalcium silicate cement (Biodentine) is a treatment choice for mechanical pulp exposures or for carious exposures.
The patient needs to understand that the tooth is still at risk for need for endodontic treatment at a later time. Follow-up evaluations is crucial to evaluate pulpal vitality. To these authors, this innovative bioactive tricalcium silicate cement is a “heroic” material. Its recommended clinical uses are for those clinical situations where the clinical conditions are challenging and prognosis is questionable. These clinical uses include restoring root perforations, restoration of internal and external resorption, and for apexification.OH
Howard E. Strassler, DMD, Professor, Director Operative Dentistry, Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD, USA (410) 706-7551, email: email@example.com
Robert Levin, DDS, 18800 Delaware, St #600, Huntington Beach, CA 92648, (714) 841-0264 email: firstname.lastname@example.org
Oral Health welcomes this original article.
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