A Modern Look at the Cvek Pulpotomy

REVIEW ARTICLE

Payman Hamadani, Nicholas Chandler A modern look at the Cvek pulpotomy

KEY WORDS Cvek pulpotomy, direct pulp cap, mineral trioxide aggregate (MTA)

ABSTRACT The Cvek pulpotomy procedure has been in use for over 40 years since the technique was ﬁrst published in 1978. The original technique remains unchanged; however, the materials used have evolved considerably. This article explores the developments in materials and the clinical procedure since the late 1970s and discusses how they might inﬂuence outcome. Two cases are presented to demonstrate common clinical scenarios that a general dental practitioner may encounter in everyday clinical practice. The treatment performed with the available materials is critiqued.

Introduction Materials and methods of Cvek

The Cvek pulpotomy procedure is primarily aimed The aim of the 1978 study by Cvek was to clinically at maintaining pulp vitality in teeth with compli- and radiologically assess the frequency of healing of cated crown fracture. It has particular application traumatic pulp exposure after a partial pulp otomy, in managing traumatic pulp exposure in immature taking into consideration the size of the pulp expo- teeth where continued root maturation is desired. It sure and the interval between accident and treat- involves removing the most inflamed portion of the ment with respect to the stage of root development. exposed dental pulp and placing a pulp cap followed In Cvek’s study1, 60 anterior teeth comprising by a restoration. The outcome is highly predictable 51 maxillary and 9 mandibular incisors in patients and unrelated to the size of the exposure and the aged between 7 and 16 years were assessed. As period between the accident and the treatment. a result of the traumatic injury, some teeth had Cvek’s landmark paper in 19781 reports no abnormal mobility, while others had increased 60 complicated crown fractures in permanent inci- movement with/without tenderness to percussion. sors in patients aged 7 to 16 years old. Almost However, the exact nature of the luxation injuries half of these teeth (28) had immature roots. A was not specified, and only the size of the pulp success rate of 96% was reported after an aver- exposure and the time interval from accident to age follow-up period of 31 months. The treatment treatment were reported. There was no mention procedure and materials used in the original study as to whether there was previous caries or his- have changed considerably. torical trauma to the injured teeth. Most of the The present article looks at the Cvek pulpotomy complicated fractures involved either a transverse procedure in light of the current literature, to con- or oblique fracture (56 teeth), and four teeth had sider modern approaches to this well-established longitudinal crown-root fractures with the apical and successful technique. As a result of improve- extent of the fracture not specified. A bleeding or ments, excellent outcomes might be predicted proliferative pulpal response was observed in all today. cases. Electric sensibility testing of the teeth was

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carried out. A positive response was reported for inter-operator variability. The initial assessment of all teeth preoperatively, even though bleeding of the injury would have entailed a detailed preopera- the pulp tissue was evident. tive medical history, dental history, nature of injury The pulpotomy treatment was carried out dur- (blunt- or sharp-force trauma) and an assessment ing two visits and by 11 dentists. The first visit of the pulp and periapical health status of teeth, involved the use of a high-speed diamond bur and and considering the possibilty of more extensive sterile saline to remove the most coronal aspect alveolar and soft tissue injuries. of the pulp tissue, leaving a 2 mm deep cavity. The pulp exposure would have been digitally Bleeding was controlled with saline followed by photographed, to allow measuring the size of the the placement of Calasept (Directa AB, Upplands exposure on a computer screen and by using imaging Väsby, Sweden), a non-setting calcium hydrox- software. A baseline record would have involved ide (CH) dressing, followed by a zinc oxide and pulp tests, primarily with CO2 snow; teeth would eugenol (ZOE) as a provisional filling material. have been assessed for luxation injuries and a peri- The sizes of the exposures were measured but the odontal depth probing would have been performed. method used was not described; wound sizes were Furthermore, a minimum of two periapical radio- between 0.5 to 4 mm. graphs with a cone-shift technique would have been At 3-week, 3- and 6-month reviews, radio- indicated to check for additional injuries, such as root graphs were used to assess the presence of a hard fractures and possible tooth luxation. Concomitant tissue barrier, and a stage-two procedure was car- injuries may affect prognosis, while teeth with ‘open’ ried out. It can only be assumed that patients did apices have a more extensive blood supply and are not have the coronal tooth structure aesthetically less susceptible to the loss of vitality following a luxa- restored until this stage-two intervention, which tion injury. in some cases was months apart. With a sharp Currently, treatment can be performed in a probe, the calcified barrier was assessed for conti- single visit. While the principles of the pulpotomy nuity. The hard tissue was then covered with Dycal procedure are basically the same, pulpal haemor- (Dentsply DeTrey, Konstanz, Germany), a hard set- rhage is now managed with a cotton pellet soaked ting CH material. Subsequently, a composite resin in sodium hypochlorite (NaOCl). Many bioactive restoration was placed; this was conducted with materials are now available that have been shown either a two-paste chemically-cured material or an to improve long-term maintenance of the pulp early light-cured resin. The use of a liner or base vitality in direct pulp capping (DPC) experiments. material was not mentioned. An average follow-up These materials are more stable over time and are period of 31 months and a 96% success rate were more effective sealants than those previously used. reported. The time elapsed after injury (up to an Haemostasis should be achieved with 3% to average of 8 days) did not influence the outcome. 6% NaOCl after 5 to 10 minutes of direct contact A longer period from injury to treatment involved with the bleeding pulp tissue. If bleeding continues just three teeth as most patients sought treatment and exceeds this time duration, then the pulp is within the first week. The partial pulpotomy was likely to be irreversibly inflamed and a full pulpot- successful in cases of closed (less than 0.5 mm) and omy or pulpectomy may be recommended. NaOCl open (more than 0.5 mm) apices. The technique in concentrations from 1.5 to 5.25% is currently for measuring the apical opening was not detailed. regarded as a safe, effective and as an inexpensive haemostatic solution for DPC and partial and com- plete pulpotomy procedures2,3. The antimicrobial Modern technique and materials properties of NaOCl solution provide haemostasis and disinfection of the dentine-pulp interface, A study of a similar nature would now require the chemical amputation of the blood clot and fibrin, approval from an ethics committee and would biofilm removal as well as removal of damaged be limited to only one operator to eliminate cells at the mechanical exposure site.

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An improved understanding of the dentine- CH dissolves over time. Tunnel defects have been pulp complex allows clinicians to harness its poten- demonstrated in the resultant hard tissue barriers. tial and maintain pulp vitality and continued root CH is also absorbable and dimensionally unsta- maturation. The transforming growth factor-beta ble12. The slow degradation of CH may lead to (TGF-`) family of growth factors is responsible for microleakage, allowing microorganisms to spread the upregulation of surviving odontoblasts and through the defects. Pulp repair using aqueous CH recruitment of fibroblasts to secrete reparative show increasing failure rates over time, as the ma- dentine at the site of injury4. These growth fac- terial is resorbed and deteriorates. tors can also be secreted by odontoblasts and pro- Non-aqueous hard-setting CH materials (cal- moted by bioactive materials such as CH, or silicate cium salicylate ester cements) are less suitable for cements, for example, mineral trioxide aggregate pulp capping due to their limited release of hydroxyl (MTA) (Dentsply Tulsa Dental, Tulsa, OK, USA), ions. Their pH is usually lower and their antimicro- or Biodentine (Septodont, Saint-Maur-des-Fossés, bial effect weaker. Materials such as Dycal (Dent- France). The formation of dentine is not possible sply DeTrey) and Life (Kerr Corp, Romulus, MI, without odontoblasts. However, a hard tissue bar- USA) suffer long-term disintegration, and may fail rier is formed after pulpotomy. This hard tissue to support an overlying permanent restoration13. barrier or ‘bridge’ is secreted by fibroblasts that Light-cured liners and base cements with CH addi- are recruited to the site of injury. The mineralised tives have been developed (e.g TheraCal LC [TLC, tissue is heterogenous, amorphous and atubular in Bisco, Schaumburg, IL, USA] and Ultrablend Plus nature and so, histologically, not dentine5. [Ultradent, South Jordan, UT, USA]). Their applica- The size of the pulp exposure has no significant tion is simpler, but despite their resin content, light- bearing on the final outcome of DPC or the Cvek cured materials have poor mechanical strength and pulpotomy procedure, but the size of the pulp their pH is low. Also, only a small amount of cal- exposure is often difficult to estimate clinic ally6. cium ions is released, and this group of materials is This may influence the decision-making process considered cytotoxic14. and result in more extensive treatments, such as Most of our current understanding of vital pulp pulpectomy and root canal treatment. However, therapy is based on the first MTA material, Pro- the remaining tooth structure and the injury are Root MTA (Dentsply Tulsa Dental). The constitu- important factors to take into account in the over- ents comprise a hydraulic calcium silicate powder all treatment plan context. containing oxide compounds, including those of calcium, iron, silicon, sodium, potassium, mag- nesium and aluminium15. The favourable phys- Materials and methods for vital pulp icochemical characteristics stimulate the tissue therapy reparative processes by recruiting and activating hard tissue-forming cells. The by-products formed One major determining factor in the healing pro- during hydration of mixed MTA include CH and cess of pulp tissue is the presence or absence of calcium silicate hydrate, which sustain an alka- microorganisms. In the absence of microorgan- line pH environment for prolonged periods. Blood isms, exposed pulps in rats were successfully sealed does not affect the setting of MTA16. There is an with mineralised tissue even without the place- excellent marginal adaptability of MTA to dentine, ment of a medication or a restoration7. with components penetrating the tubules to give Aqueous CH has been considered as the adhesion, which is comparable to a glass iono- standard material for vital pulp therapy for many mer cement (GIC). MTA promotes a biocompat- years8-11. Its high alkaline pH, which stimu- ible, non-cytotoxic, antimicrobial environment and lates fibroblasts and neutralises the low pH of favourable surface morphology for bridge forma- acids, has antibacterial properties and promotes tion. A significant disadvantage of MTA, of spe- defence mechanisms and repair. Unfortunately, cial relevance to the Cvek pulpotomy in anterior

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teeth, is coronal tooth discolouration. Its constitu- materials. The most durable bond strengths are ents, which are metals such as bismuth oxide or achieved by using selective etching of enamel with iron, may oxidise and promote this adverse effect. 34% to 37% phosphoric acid, followed by two- Other calcium silicate-based cements contain zir- step, two-bottle, self-etching adhesive systems26,27. conia or tantalum oxide as radiopacifiers and these Following treatment, the pulp health status must be are more colour-stable; hence less likely to cause assessed periodically to ensure continued pulp vital- tooth discolouration. ity and the development of dentine in the walls of Many newer calcium silicate cements show the root canal and, in immature teeth, apical closure. physicochemical and bioinductive properties com- Even with modern techniques and biocompat- parable to MTA17-19. The most popular product ible materials, a statistically significant difference among nearly 40 available on the market is Bio- in the successful outcome, might not be achieved dentine, which demonstrates strong bioactive and within a short follow-up period, compared with antibacterial properties20. the Cvek (1978) study. However, improved prog- ZOE, used by Cvek in 1978, has traditionally nosis is expected in the near future with today’s been used as a base under restorations or as a pro- techniques employing newer materials. visional material21. ZOE has strong antibacterial activity against Streptococcus mutans and other microorganisms within infected dentinal tubules22. Case 1 Although eugenol has been shown to have an inhib- itory effect on the polymerisation of the composite A 24-year-old male patient presented with a com- resin, it can still be considered as a suitable base, but plicated enamel-dentine fracture in the maxillary a bonding agent is essential to avoid polymer isation left central incisor due to a surfing accident that shrinkage-induced detachment21. occured 4 hours previously; the coronal fragment GICs were in their infancy in the mid-1970s and was lost (Fig 1a). The clinical examination revealed at that time were supplied as powder and liquid a tooth with a 0.5 mm pulp exposure and enamel formulations for spatulation. Today, an interposed cracks cervically (Fig 1b); there was no abnormal liner of a capsulated GIC formulation is used to tooth mobility. A periapical radiograph revealed a protect the capping material, as well as to bond to normal root maturation and no obvious luxation the MTA and the composite resin. Dentine adhe- injury (Fig 1c). The periodontal probing depths sives and composites are not biocompatible and were less than 3 mm. Teeth 11 (maxillary right should not be used for pulpotomy procedures. central incisor), 21 (maxillary left central incisor) Resin-modified glass ionomer cements (RMGIC) and 22 (maxillary left lateral incisor) were vital to and some hydrophilic cements are excellent seal- cold testing with no injuries to tooth 11 or 22. The ants when combined with light-cured compos- treatment plan involved a Cvek pulpotomy and ite resins as permanent restorations, and placed restoration with composite resin. directly over DPC materials such as MTA or other After administration of a local anaesthetic and calcium silicate cements23-25. dental dam application, a high-speed straight Nowadays, instead of attending two appoint- diamond bur was used with water coolant to ments, patients can have their teeth permanently remove 2 mm of the coronal pulp tissue. Bleed- restored during the pulpotomy treatment (per- ing was arrested within 20 seconds with a cotton formed in one appointment). The final restoration pellet soaked in NaOCl. A hard-setting calcium is placed with the aim of sealing the pulpotomy silicate cement was placed over the wound fol- material, and to further defend the pulp from micro- lowed by light-cured TheraCal LC resin (Fig 1d), leakage and microbial challenges. Adhesive restora- and covered with a RMGIC (Vitrebond, 3M, St tive materials preserve the remaining tooth struc- Paul, MN, USA), which was also light-cured. The ture, and current etching systems produce excellent crown was restored with G-aenial composite resin bond strengths to enamel, dentine and cured DPC (GC Corporation, Tokyo, Japan) (Fig 1e).

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Fig 1a to f Case 1: (a) Tooth 21 (maxillary left central incisor) coronal fracture; the fractured fragment was lost; (b) The exposed pulp of tooth 21 was evident; (c) Radiograph of tooth 21; (d) Direct pulp capping of the wound; (e) The crown of tooth 21 was restored with composite resin; (f) Follow-up radio- a b c graph 1 week after the accident.

d e

The management of traumatic dental injuries pathological changes. A ceramic restoration is challenging for a general dental practitioner (veneer or crown) may be required in the future as it often presents as an emergency. Emergency to improve aesthetics of the tooth21. appointments may not be available or a short time period appointment might only be available and, often the ideal materials are not at hand. In Case 2 particular, in relation to cases that present as an emergency during the night or weekends, with An 11-year-old male patient presented with a clinicians being forced to operate in unfamiliar complicated enamel-dentine fracture to tooth 21 surroundings. In these cases, the use of materials (maxillary left central incisor) after suffering a fall such as Biodentine or MTA seem more appropri- 5 hours previously; the fractured coronal fragment ate since TheraCal only releases a small amount of was retrieved. The clinical examination revealed calcium28 and is cytotoxic. The pH is also signiﬁ- a 0.5 mm bleeding pulp exposure (Fig 2a); there cantly lower compared with other CH products29. was no abnormal tooth mobility. A radiograph of A Cvek pulpotomy was the appropriate treatment the maxillary left central incisor revealed an imma- and the composite resin restoration provided a ture root with open apex and no luxation injury good immediate seal and aesthetic result. At the (Fig 2b). Periodontal probing depths were less than 1 week follow-up, tooth 21 was symptom-free 3 mm. Teeth 11 (maxillary right central incisor), 21 and the pulp responded to cold testing (Fig 1f). (maxillary left central incisor) and 22 (maxillary left A long-term follow-up is essential to detect any lateral incisor) were responsive to cold, with no

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Fig 2a to e Case 2: (a) Bleeding pulp exposure of tooth 21 (maxillary left central incisor); (b) A radiograph of tooth 21 reveals incomplete apical development; (c) Coronal fractured fragment of tooth 21 reattached; (d) A 6-month follow-up radiograph of tooth 21; (e) A 1-year follow-up radiograph of tooth 21; ab the apical closure was evident.

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obvious injuries to tooth 11 or 22. The treatment very good outcomes, in this case, a DPC was per- plan involved a direct pulp cap followed by bond- formed. However, it would have been more appro- ing of the coronal fragment with composite resin. priate to carry out a Cvek pulpotomy, removing After administration of a local anaesthetic and part of the coronal pulp tissue. A small cavity was dental dam application, a high-speed diamond bur prepared within the coronal fragment to provide with water coolant was used to remove 2 mm of space for the DPC of MTA, which allowed good the tooth structure from the coronal fragment to approximation. MTA has been shown to discolour provide space for the DPC material. ProRoot MTA tooth structure; Biodentine or an alternative, with (Dentsply) was placed over the exposure site and similar properties, were not available. However, covered with a RMGIC (Vitrebond, 3M) and was the patient and his parents were happy with the light-cured. The coronal fragment was bonded to aesthetic result achieved. the fractured site with RelyX Unicem (3M ESPE, St Paul, MN, USA) and was also light-cured (Fig 2c). After 6 months, when tested, the tooth responded References to cold and the periapical tissues appeared normal 1. Cvek M. A clinical report on partial pulpotomy and cap- on a check radiograph (Fig 2d). The situation was ping with calcium hydroxide in permanent incisors with the same, at review, after 1 year (Fig 2e). complicated crown fracture. J Endod 1978;4:232–237. 2. Haghgoo R, Abbasi F. A histopathological comparison of This case was also managed by a general den- pulpotomy with sodium hypochlorite and formocresol. tal practitioner. Fortunately, the fractured tooth Iran Endod J 2012;7:60–62. fragment was retrieved and it ﬁtted perfectly 3. Witherspoon DE. Vital pulp therapy with new materials: new directions and treatment perspectives — permanent when replaced. As MTA has been shown to have teeth. Pediatr Dent 2008;30:220–224.

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Payman Hamadani, BDS Nicholas Chandler, BDS, MSc, PhD Sir John Walsh Research Institute, Fac- Professor, Sir John Walsh Research Insti- ulty of Dentistry, University of Otago, tute, Faculty of Dentistry, University of Dunedin, New Zealand Otago, Dunedin, New Zealand

Payman Hamadani

Correspondence to: Professor Nicholas Chandler, School of Dentistry, University of Otago, PO Box 56, Dunedin 9054, New Zealand. E-mail: [email protected]

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