- Email: [email protected]
Efficacy of EMD versus calcium hydroxide in direct pulp capping of primary molars: a randomized controlled clinical trial
Efficacy of EMD versus calcium hydroxide in direct pulp capping of primary molars: a randomized controlled clinical trial Arturo Garrocho-Rangel, DDS, MS,a Hector Flores, DDS, PhD,b Daniel Silva-Herzog, DDS,c Francisco Hernandez-Sierra, MD, MS,d Peter Mandeville, MS,e and Amaury J. Pozos-Guillen, DDS, PhD,a,c San Luis Potosí, México UNIVERSIDAD AUTÓNOMA DE SAN LUIS POTOSÍ
Objective. The aim was to compare the clinical and radiographic efficacy of enamel matrix derivative and selfhardening calcium hydroxide as direct pulp capping materials on decayed primary molars, with observation periods of 1, 6, and 12 months. Study design. A clinical, randomized, controlled trial was performed, following the “split-mouth” design. A total of 90 primary molars were treated. Assignation of materials and operative initial side were selected in a randomized manner. Five outcome variables were considered: internal dentin resorption, pain, gingival sinus tract, root external resorption, and pathologic mobility. The appearance of any of these signs or symptoms was considered to be a failure of treatment. Results. Significant statistical or clinical differences were not found between the study groups. Two treatments were judged as failures, 1 per study group; both occurred during the first postoperative month. Conclusions. The technique used for direct pulp capping on primary molars in this study is recommended on the basis of the obtained clinical and radiographic results. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;107: 733-738)
One of the primary objectives of pulp therapy in pediatric dentistry is to maintain the integrity, health and function of deeply decayed primary teeth and their supporting structures.1 The dental pulp is essentially a connective tissue composed of fibroblasts and odontoblasts, with inherent capability to produce reparative dentin when the environment is favorable.2 Direct pulp capping (DPC) is an accepted and commonly used procedure for permanent teeth; however, in primary teeth this treatment is a cause of distrust and controversy3; some authors have shown successful rates,3-6 whereas others discourage it, owing to the high possibility of causing internal dentin resorption, explained because undifferentiated mesenchymal cells in the primary pulp may become odontoclasts, leading to this a
Associate Professor, Pediatric Dentistry Postgraduate Program, Facultad de Estomatología. b Professor and Head, Endodontics Postgraduate Program, Facultad de Estomatología. c Associate Professor, Endodontics Postgraduate Program, Facultad de Estomatología. d Professor and Head, Clinical Epidemiology Postgraduate Program, Facultad de Medicina. e Associate Professor and Head, Clinical Epidemiology Department, Facultad de Medicina. 1079-2104/$ - see front matter © 2009 Published by Mosby, Inc. doi:10.1016/j.tripleo.2008.12.017
resorption.1,7,8 Other harmful effects have been reported: pulp inflammation and calcifications and periradicular bone loss.1 For that reason, pulpotomy is preferred when any kind of pulp exposure occurs, regardless of its origin, e.g., caries, trauma, or cavity processing.3 Enamel extracellular matrix has been related to important biologic functions in tooth development9 and successfully used in dentistry in the form of enamel matrix derivative (EMD) to incite natural cementogenesis to restore a fully functional periodontal ligament, cementum, and alveolar bone10 in the treatment of intrabony defects in patients with severe and advanced periodontitis, through regeneration of the affected tissues.11-13 When applied to denuded root surfaces, EMD forms a matrix that locally facilitates regenerative responses in the adjacent periodontal tissues.14 EMD is obtained from developing porcine tooth buds. It contains an amelogenin and amelin protein-rich fraction, and is available in gel form with propylene glycol alginate as a vehicle (Emdogain; Biora, Malmö, Sweden). Amelogenin and amelin are structural proteins in the enamel matrix that play an important role in enamel formation.15 So far, Emdogain is the only material on the market that has potential for actually triggering regenerative responses in periodontal ligament cells.16 EMD is also used in cases of dental reimplantation17 and as a material of DPC, both in animal teeth18-20 and 733
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in human permanent teeth.21 It is also used as a dressing in pulpotomies of primary teeth22 with successful clinical and histologic results. It has been demonstrated that EMD induces a large amount of new dentin-like tissue when applied as DPC material onto the exposed pulp tissue of permanent molars in the adult miniature swine.18 Enamel matrix derivative has the potential to induce a regenerative process consisting of differentiation of odontoblasts and subsequent dentin formation and pulpal wound healing without affecting the normal function of the remaining pulp, in a manner similar to normal odontogenesis;10,23 it is believed that enamel matrix proteins participate in the reciprocal ectodermalmesenchymal signaling that controls this process.11 Additionally, EMD induces odontoblasts and endothelial cells of pulp capillary vessels to produce a hard tissue barrier over a pulp exposure.21 This biomaterial has been shown to be clinically resistant, because amelogenin and amelin are recognized as “autoproteins” by the human defense system, and no allergic or immunologic reactions have been reported during ⬎10 years of use.13,24 The aim of the present study was to evaluate the clinical and radiographic efficacy of EMD and to compare it with self-hardening calcium hydroxide in DPC treatment on primary molars during a 12-month follow-up period. MATERIALS AND METHODS Design This study was approved by the Ethics Committee on Investigation at the Faculty of Dentistry of San Luis Potosi University, Mexico. It was designed as a randomized controlled clinical trial using the “splitmouth” variant. The various steps of the study followed the guidelines suggested by the CONSORT group25 for planning and reporting clinical trials in pediatric endodontics with the highest levels of evidence. Selection criteria Participants consisted of either gender of pediatric patients that exhibited 2 deeply decayed primary molars located on opposite sides of the mouth (maxillary or mandibular), restorable and with at least one-half of their root length, with clinical and radiographic data indicating treatment with direct pulp cappingh. Exclusion criteria were the presence of any clinical or radiographic sign or symptom of pulpitis or pulp necrosis, teeth about to be exfoliated, and patients diagnosed with a systematic or immunocompromising illness. Enrollment of participants was done by an independent, blind, and precalibrated experienced observer.
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Interventions All patients were treated at the clinic of the Pediatric Dentistry Postgraduate Program, Faculty of Dentistry of San Luis Potosi University, Mexico. A single operator carried out all of the operative procedures. Written informed consent was obtained from the participants’ parents. To standardize the technique, the complete operative procedure was practiced on extracted deeply decayed primary molars before the study. The operative technique is described briefly as follows. After anesthesia, the selected molar was isolated with a rubber dam and cleaned. Elimination of all peripheral decayed tissue was accomplished with a high-speed, #4 carbide round bur (Indeco/plus, Mexico City, Mexico). Then a standard and noncarious 1-mm pulp exposure was created with a #3 carbide round bur so that all exposures were of the same standard width; then the nature of the bleeding was reviewed: light red color and hemostasis in 2 or 3 minutes. The exposure was carefully washed with alternating irrigations of sterile saline and chlorhexidine solution (Consepsis; Ultradent Products, St. Jordan, UT) and dried gently with sterile cotton pellets. Immediately, the material was placed over the exposure with a round-head metallic applicator: EMD (Emdogain) in the experimental group and self-hardening calcium hydroxide (Dycal; Dentsply Caulk, Milford, ME) in the control group. Then the cavity was sealed with a cover of dentine adhesive (Singlebond; 3M Unitek, Monrovia, CA), another cover of glass ionomer (Vitrebond; 3M Espe, St. Paul, MN), both photopolymerized for 40 seconds; finally, a preformed metallic crown (3M Espe) was adapted and cemented (PCA; SS White, Gluocester, U.K.). Each patient was scheduled to be seen 1, 6, and 12 months after the operative procedures. During these appointments, the same observer who selected the patients carried out a complete clinical and radiographic review of the treated molars. Radiographs were taken using a film holder with the paralleling technique, with standardized exposure times and processing. It had been previously determined that the presence of any of the following signs or symptoms would be indicative of failure of the treatment: internal dentin resorption, spontaneous pain, gingival abscess (sinus tract), external root resorption, or pathologic mobility—all of them measured dichotomously. A total follow-up period of 12 months was selected on the basis of earlier studies6,21,26 that used periods from 60 to 120 days; findings from those studies show that at day 63, a dentin bridge was already observed. Reproducibility tests were undertaken at the beginning of the study to calibrate the evaluating observer. Unweighted kappa method was used for each sign or
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Table I. Number of successful and failed treatments per study group at the 3 evaluation times Follow-up 1 month Group of study EMD Ca(OH)2 Total*
6 months
12 months
Success
Failure
Success
Failure
Success
Failure
44 44 88
1 1 2
44 44 88
0 0 0
44 44 88
0 0 0
EMD, Enamel matrix derivative (Emdogain); Ca(OH)2, self-hardening calcium hydroxide (Dycal). *Both failures occurred during the first postoperative month.
symptom, obtaining good to excellent scores [from 0.7406 (95% CI 0.5471-0.9342; P ⫽ .000384) to 0.8976 (95% CI 0.7422-1.000; P ⫽ 1.37 e⫺08], according to Landis and Koch’s criteria.27 Sample size The sample was obtained with a nonprobabilistic method (consecutive cases), from the patient population that visited the clinics between July 2006 and February 2007. The total sample consisted of 45 pediatric patients, for a total of 90 treated primary molars. The sample size calculation was performed with an 80% power, on the basis of a reported incidence of internal dentin resorption.28 This is the sign that appears most frequently when DPC with calcium hydroxide is carried out on primary teeth1,7,8; therefore, it was considered as the outcome variable that would determine a real difference between the 2 materials. This difference, to be considered minimally clinically and statistically significant, was set at 20%. The sample size calculation used the formula for repeated measures. Randomization Selection of initial side of treatment in the mouth and allocation of DPC material for each molar were undertaken at random using number sequences generated by R 2.4.0 software). Two lists of random numbers were created, one corresponding to the capping material used in the initial operative appointment [odd number for EMD and even for Ca(OH)2] and the other to determine the side of the mouth that was treated at that appointment (odd for the left side and even for the right), following the split-mouth design; at the next appointment the other material on the opposite side was used. Each pair of numbers (from list 1 and list 2) corresponded to each patient. The operator was blind to the random number schemes until just before placing the materials. Blinding In this study, the participants, assessing observer, and analyst were blind regarding capping material
group assignation. Because Emdogain and Dycal each has recognizable characteristics, they could not be blinded to the operator. Statistical methods Outcome variables in this study were dichotomous. A clinical failure was recorded if the tooth presented any of these clinical or radiographic variables. Tooth type and location were also considered. Fisher exact test was used. A difference was considered to be significant if the probability that it occurred by chance alone was less that 5% (p ⬍ .05) in a 2-tailed test. R 2.4.0 software was used to perform the statistical analysis. RESULTS The recruitment period for eligible children was 7 months. Fifty-six subjects were recruited for this trial, and 11 were excluded. All of the 45 participants completed the follow-up according to the designed protocol. The descriptive analysis shows that gender distribution was 58% female and 42% male. Median age was 5.7 years (SD 1.01) for girls and 6.4 years (SD 1.16) for boys. The largest proportion was found in the 6-year group of both genders. There were no significant differences in age or gender between the study groups (P ⫽ .999). In total, 90 DPC treatments were performed (45 in the experimental group and 45 in the control group) and followed for 12 months. There were 88 successful treatments at the end of this period, with only 2 considered to be failures (1 per study group): a maxillary left first molar in the EMD group presented spontaneous pain, abnormal mobility, swelling, and a gingival abscess, and in the control group, a mandibular right second molar exhibited internal dentin resorption in the postoperative radiograph. Both teeth showed those abnormalities during the first follow-up month (Table I). Description of each outcome variable in each study group and during evaluation times is shown in Table II. There were no other adverse events reported. Regarding the number of treatments undertaken on each pri-
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Table II. Incidence of each outcome variable at 1, 6, and 12 months of follow-up Outcome variable Abscess Group of study EMD
Ca(OH)2
Mobility
IDR
Pain
PBR
Time
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
1 month 6 months 12 months 1 month 6 months 12 months
1 0 0 0 0 0
44 44 44 45 45 45
1 0 0 0 0 0
44 44 44 45 45 45
0 0 0 1 0 0
45 45 45 44 44 44
0 0 0 0 0 0
45 45 45 45 45 45
1 0 0 0 0 0
44 44 44 45 45 45
IDR, Internal dentin resorption; PBR, pathologic bone resorption. Other abbreviations as in Table I.
mary molar, the tooth receiving the most treatments was the mandibular left first molar, with 14 cases; the one with the least number of procedures was the maxillary right first molar, with only 9 cases. There were no significant differences as to the type of treated molar and localization (P ⫽ 1.000). On the basis of the results obtained in the analysis, statistical differences between the 2 treatment groups could not be found (P ⬎ .05). DISCUSSION The dental pulp is a highly vascular and innervated connective tissue that is capable of healing by forming hard-tissue barriers or dentin bridges after DPC.22,29 Innovative therapies have been used in an attempt to apply biologic modulators that have been identified during tooth and bone embryogenesis and cloned experimentally; these agents are intended to improve treatment modalities and induce tissue regeneration.30 Dental pulp capping has almost disappeared from the wide repertory of pulp treatments in primary teeth, because it is considered to be a compromising and risky procedure owing to its likelihood of producing internal dentin resorption26 and, with less frequency, pulp calcification, necrosis, and damage to the surrounding alveolar bone.1 Higher cell concentration of the primary pulp tissue could be the cause of these abnormalities; it is supposed that the mesenchymal cells become differentiated to odontoclastic cells in response to the capping material (calcium hydroxide), thereby causing internal root resorption.26 DPC has been limited to those cases where exfoliation of affected primary teeth is expected within 1 or 2 years. Moreover, an ideal material for DPC of primary teeth has not been completely accepted; although calcium hydroxide promotes healing and maintains the vitality of pulp tissue, harmful effects on the treated tooth or its periradicular tissues have been reported.1 Nor has there been a standardized DCP technique for primary teeth, such as those developed or suggested by experienced clini-
cians,3,31 that considerably improves the prognosis of treatment. In the present study, 2 capping materials were compared; these materials have different mechanisms of action. Calcium hydroxide is applied directly to the pulp tissue; because of its high alkaline pH, it produces a limited necrotic zone of superficial liquefaction necrosis that causes a mild irritation, promoting pulp cells to differentiate into new odontoblasts (also called odontoblast-like cells, odontoblastoids, or pseudodontoblasts) that place a mineralized dentin bridge on the pulp exposure.18 The newly formed hard tissue resembles secondary dentine from the very onset of the reparative process.10 On the other hand, EMD, because of its amelogenin and amelin-rich fraction, has the potential to induce a process that seems to imitate normal dentinogenesis; it clearly influences the odontoblasts and endothelial cells of the pulp capillary vessels to create a hard calcified barrier over the pulp exposure.19,21 It has been reported that enamel matrix proteins participate in differentiation and maturation of the odontoblastic cells, and when the pulp wound is exposed to EMD a substantial amount of reparative dentin-like tissue is formed in a process much resembling classic wound healing, with subsequent neogenesis of normal pulp tissues. The formation of new dentin starts from within the pulp at some distance from the exposure site.10 Also, EMD promotes an intracellular cyclic adenosine monophosphate signal in mesenchymal cells; this intracellular signal is followed by secretion of autocrine growth factors and a subsequent increased proliferation and maturation of extracellular matrix-secreting cells.14 EMD has been shown to induce expression of integrins in cultured fibroblasts, which play an important role in mesenchymal cell development and function.10 Three reasons can be mentioned to explain the high success rate obtained for both capping materials in the present study:
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1. Strict participant selection, both clinically and radiographically. One of the factors that greatly improves the prognosis of the DPC procedure is the absence of inflammation of the exposed pulp tissue2; this was meticulously observed during diagnostic and treatment phases. 2. Performing a careful operative technique based on recommendations from previous studies.3,21,31 All carious tissue was removed before DPC, because necrotic and infected dentin chips can impede healing of the exposure by causing further pulpal inflammation.3 On the other hand, standardization of exposure size was achieved using a 1-mm-diameter round bur in all of the interventions; this wide exposure had 3 purposes: to remove the inflamed or infected pulp tissue from the exposed area, to facilitate washing away carious or contaminated dentine debris, and to allow a closer contact between the capping material and the exposed pulp tissue.3,32 Limiting the width of pulp exposure may favorably influence the pulp-capping therapy, because the availability of odontoblast-like cells appears to be limited; larger exposures are also likely to generate a greater quantity of debris that could impair pulptissue healing.29 Moreover, 2 fundamental pediatric endodontic principles were observed: operating under conditions of absolute isolation and the constant maintenance of an aseptic operating field. Further precautions were avoiding clot formation on the exposed pulp,3 profuse rinsing of the exposure with chlorhexidine and sterile saline solutions, and immediate placing of the capping materials. 3. Microleakage was controlled to the utmost; this factor greatly affects the prognosis of pediatric pulp treatments.33 A bacteriometic seal permits pulp reparative activity to occur naturally beneath capping materials. It has been observed that bacterial microleakage reduces the odontoblast-like secretion of dentin bridges; this may lead to the development of postoperative complications if the bridge cannot protect the pulp from injury.29 A layer of glass ionomer was placed, together with a metallic crown restoration, which offers superior resistance to fracture and microleakage compared with IRM, glass ionomer, or Cavit.34 Few comparative studies have reported use of the same DPC materials. Olsson et al.21 carried out the procedure in 9 pairs of caries-free premolars scheduled for extraction for orthodontic purposes, with a 12-week postoperative observation period. In comparing results, we found some differences. The present study was undertaken in deeply decayed primary molars, and the follow-up time was longer. Additionally, Olsson et al.
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used Teflon discs fixed by wax to hold the capping materials, sealing the cavity with zinc oxide– eugenol cement and glass ionomer. For the same purpose, we placed a dentin adhesive and glass ionomer coats, restoring with a metallic crown. Regarding the observed results, they reported fewer postoperative symptoms in the EMD group, whereas we found no significant differences between our 2 groups in relation to incidence of postoperative signs or symptoms. Their immunohistochemical analysis exhibited new hard tissue, which partly replaced the EMD gel in the exposure site, and a larger amount of inflammatory tissue in relation to calcium hydroxide, which formed a hard mineralized bridge whose aspect was markedly different and of insufficient quality to act as a protective barrier. One of the goals of the present study was to reconsider the use of DPC on primary teeth as a less invasive alternative to pulpotomy, because DPC has potential clinical applications and shows promising results. Our recommendations that might improve the prognosis of DPC on primary molars are: 1) careful selection of cases based on a meticulous clinical and radiographic diagnosis; 2) operative procedures under absolutely aseptic conditions; 3) adequate exposure size; 4) disinfection of the exposed area with chlorhexidine and saline rinses; and 5) control of microleakage by placement of the dentine adhesive, glass ionomer, and preformed metallic crown. We conclude that there were no statistically or clinically significant differences between EMD (Emdogain) and self-hardening calcium hydroxide (Dycal) regarding the appearance of pathologic signs or symptoms when used as DPC materials on pulp exposures of 1 mm diameter in primary molars. Both capping materials showed a similar effectiveness in this pulp procedure, with a postoperative observation time of 12 months. On the basis of this study, we recommend the use of DCP treatment on primary molars as a standardized technique. The authors thank Dr. Carlos Garrocho-Sandoval for reviewing the manuscript and Norman Wahl for his assistance in editing the manuscript. REFERENCES 1. Fuks A. Pulp therapy for the primary and young permanent dentition. In: García-Godoy F, editor. Dental clinics of north america. Philadelphia: Saunders; 2000p. 578-81. 2. Yamamura T. Differentiation of pulpal cells and inductive influences of various matrices with reference to pulpal wound healing. J Dent Res 1985;64:530-40. 3. Kopel H. Considerations for the direct pulp capping procedure in primary teeth: a review of the literature. J Dent Child 1992;60:141-9. 4. Pereira C, Stanley HR. Pulp capping: influence of the site on pulp healing: histological and radiographic study in dogs’ pulp. J Endod 1981;7:213-23.
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5. Sawusch R. Direct and indirect pulp capping with two new products. J Am Dent Assoc 1982;104:459-62. 6. Turner C, Courts F, Stanley H. A histological comparison of direct pulp capping agents in primary canines. J Dent Child 1987;54:423-8. 7. Camp J. Pediatric Endodontics: Endodontic treatment for the primary and young permanente dentition. In: Cohen S, Burns RC, editors. Pathways of the pulp. 8th ed. St. Louis: Mosby Year Book; 2002. p. 880-4. 8. Rood H, Waterhaouse P, Fuks A, Fayle S, Moffat M. Pulp therapy for primary molars. Int J Paediatr Dent 2006;16(Suppl 1):15-23. 9. Yuan K, Chen CL, Lin MT. Enamel matrix derivative exhibits angiogenic effect in vitro and in a murine model. J Clin Periodontol 2003;30:732-38. 10. Nakamura Y, Hammarström L, Matsumoto K, Lyngstadaas SP. The induction of reparative dentine by enamel proteins. Int Endod J 2002;35:407-17. 11. Hammarström. Enamel matrix, cementum development and regeneration. J Clin Periodontol 1997;24,658-68. 12. Heijl L, Heden G, Svardstrom G, Ostegren A. Enamel matrix derivative (Emdogain) in the treatment of intrabony periodontal defects. J Clin Periodontol 1997;24:705-14. 13. Esposito M, Grusovin MG, Coulthard P, Worthington HV. Enamel matrix derivative (Emdogain) for periodontal tissue regeneration in intrabony defects. Cochrane Database Syst Rev 2005;19:CD003875. 14. Lyngstadaas S, Lundberg E, Ekdahl H, Andersson C, Gestrelius S. Autocrine growth factors in human periodontal ligament cells cultured on enamel matrix derivative. J Clin Periodontol 2001;28:181-8. 15. Hu JC, Sun X, Zhang C, Zimmer JP. A comparison of enamelin and amelogenin expression in developing mouse molar. Eur J Oral Sci 2001;109:125-32. 16. Gestrelius S, Andersson C, Lidström D, Hammarström L, Somerman M. In vitro studies on periodontal ligament cells and enamel matrix derivative. J Clin Periodontol 1997;24:685-92. 17. Lam K, Sae-Lim V. The effect of Emdogain gel on periodontal healing in replanted monkeys’ teeth. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;97:100-7. 18. Nakamura Y, Hammarström L, Lundberg E, Ekdahl H, Matsumoto K, Gestrelius S. Enamel matrix derivative promotes reparative processes in the dental pulp. Adv Dent Res 2001;15:105-7. 19. Tatsunari N, Matsumoto K. Histopathological study of dental pulp tissue capped with enamel matrix derivative. J Endod 2003; 29:176-9. 20. Igarashi R, Sahara T, Shimizu M, Sasaki T. Porcine enamel matrix derivative enhances the formation of reparative dentine and dentine bridges during wound healing of amputated rat molars. J Electron Microsc 2003;52:227-36. 21. Olsson H, Davies JR, Holst KE, Schröder U, Peterson K. Dental pulp capping: effect of Emdogain gel on experimentally exposed human pulps. Int Endod J 2005;38:189-94.
22. Sabbarini J, Mounir M, Dean J. Histological evaluation of enamel matrix derivative as a pulpotomy agent in primary teeth. Pediatr Dent 2007;29:475-9. 23. Papagerakis P, MacDougall M, Hotton D, Baillieul-Forestier I, Oboeuf M, Berdal A. Expression of amelogenin in odontoblasts. Bone 2003;32:1-130. 24. Wilson T. Safety testing of Emdogain. In: Wilson T, editor. Periodontal regeneration enhanced. Chicago: Quintessence; 1999. p. 23-5. 25. Altman D, Schulz K, Moher D, Egger M, Davidoff F, Elbourne D. et al. The revised CONSORT statement for reporting randomized trials: explanation and elaboration. Ann Intern Med 2001;134:663-94. 26. Cehreli Z, Turgut M, Olmez S, Dagdeviren A, Atilla P. Short term human primary pulpal response after direct pulp capping with fourth-generation dentin adhesives. J Clin Pediatr Dent 2000;25:65-71. 27. Sackett D, Haynes R, Guyatt G, Tugwell P. El examen clínico. In: Sackett D, editor. Epidemiología clínica. Buenos Aires: Panamericana; 1997. p. 43-5. 28. Rabinowitch BZ. Internal resorption. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1972;33:263-82. 29. Murray PE, Hafez A, Smith A, Windsor L, Cox F. Histophometric analysis of odontoblast-like cell numbers and dentine bridge secretory activity following pulp exposure. Int Endod J 2003;36:106-16. 30. Britto LR, Jiang J, Vertucci FJ. The role of biological modulators in endodontic therapy. Rev Fac Odontol Bauru 2002;10:201-8. 31. Becerra L, Campos A. Proteçao pulpar direta. In: Becerra L, editor. Odontopediatría. Bases científicas para la práctica clínica. Sao Paulo: Artes Médicas; 2005. p. 537-66. 32. Schröder U, Szpringer-Nodzak M, Janicha J, Waciúnka M, Budny J, Mlosek K. A one-year follow-up of partial pulpotomy and calcium hydroxide capping in primary molars. Endod Dent Traumatol 1987;3:304-6. 33. Guelmann M, Fair J, Turner C, Courts, F. The success of emergency pulpotomies in primary molars. Pediatr Dent 2002;24: 217-20. 34. Dittel M, Garrocho A, Méndez V, Hernández F, Pozos A. Grado de sellado marginal de materiales de obturación temporal en molares primarios con pulpotomía: estudio in vitro. Rev Odontol Mex 2006;10:83-7. Reprint requests: Dr. Amaury de Jesús Pozos Guillén Facultad de Estomatología Universidad Autónoma de San Luis Potosí Av. Dr. Manuel Nava #2 Zona Universitaria, C.P. 78290 San Luis Potosí México. [email protected]
Objective. The aim was to compare the clinical and radiographic efficacy of enamel matrix derivative and selfhardening calcium hydroxide as direct pulp capping materials on decayed primary molars, with observation periods of 1, 6, and 12 months. Study design. A clinical, randomized, controlled trial was performed, following the “split-mouth” design. A total of 90 primary molars were treated. Assignation of materials and operative initial side were selected in a randomized manner. Five outcome variables were considered: internal dentin resorption, pain, gingival sinus tract, root external resorption, and pathologic mobility. The appearance of any of these signs or symptoms was considered to be a failure of treatment. Results. Significant statistical or clinical differences were not found between the study groups. Two treatments were judged as failures, 1 per study group; both occurred during the first postoperative month. Conclusions. The technique used for direct pulp capping on primary molars in this study is recommended on the basis of the obtained clinical and radiographic results. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;107: 733-738)
One of the primary objectives of pulp therapy in pediatric dentistry is to maintain the integrity, health and function of deeply decayed primary teeth and their supporting structures.1 The dental pulp is essentially a connective tissue composed of fibroblasts and odontoblasts, with inherent capability to produce reparative dentin when the environment is favorable.2 Direct pulp capping (DPC) is an accepted and commonly used procedure for permanent teeth; however, in primary teeth this treatment is a cause of distrust and controversy3; some authors have shown successful rates,3-6 whereas others discourage it, owing to the high possibility of causing internal dentin resorption, explained because undifferentiated mesenchymal cells in the primary pulp may become odontoclasts, leading to this a
Associate Professor, Pediatric Dentistry Postgraduate Program, Facultad de Estomatología. b Professor and Head, Endodontics Postgraduate Program, Facultad de Estomatología. c Associate Professor, Endodontics Postgraduate Program, Facultad de Estomatología. d Professor and Head, Clinical Epidemiology Postgraduate Program, Facultad de Medicina. e Associate Professor and Head, Clinical Epidemiology Department, Facultad de Medicina. 1079-2104/$ - see front matter © 2009 Published by Mosby, Inc. doi:10.1016/j.tripleo.2008.12.017
resorption.1,7,8 Other harmful effects have been reported: pulp inflammation and calcifications and periradicular bone loss.1 For that reason, pulpotomy is preferred when any kind of pulp exposure occurs, regardless of its origin, e.g., caries, trauma, or cavity processing.3 Enamel extracellular matrix has been related to important biologic functions in tooth development9 and successfully used in dentistry in the form of enamel matrix derivative (EMD) to incite natural cementogenesis to restore a fully functional periodontal ligament, cementum, and alveolar bone10 in the treatment of intrabony defects in patients with severe and advanced periodontitis, through regeneration of the affected tissues.11-13 When applied to denuded root surfaces, EMD forms a matrix that locally facilitates regenerative responses in the adjacent periodontal tissues.14 EMD is obtained from developing porcine tooth buds. It contains an amelogenin and amelin protein-rich fraction, and is available in gel form with propylene glycol alginate as a vehicle (Emdogain; Biora, Malmö, Sweden). Amelogenin and amelin are structural proteins in the enamel matrix that play an important role in enamel formation.15 So far, Emdogain is the only material on the market that has potential for actually triggering regenerative responses in periodontal ligament cells.16 EMD is also used in cases of dental reimplantation17 and as a material of DPC, both in animal teeth18-20 and 733
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in human permanent teeth.21 It is also used as a dressing in pulpotomies of primary teeth22 with successful clinical and histologic results. It has been demonstrated that EMD induces a large amount of new dentin-like tissue when applied as DPC material onto the exposed pulp tissue of permanent molars in the adult miniature swine.18 Enamel matrix derivative has the potential to induce a regenerative process consisting of differentiation of odontoblasts and subsequent dentin formation and pulpal wound healing without affecting the normal function of the remaining pulp, in a manner similar to normal odontogenesis;10,23 it is believed that enamel matrix proteins participate in the reciprocal ectodermalmesenchymal signaling that controls this process.11 Additionally, EMD induces odontoblasts and endothelial cells of pulp capillary vessels to produce a hard tissue barrier over a pulp exposure.21 This biomaterial has been shown to be clinically resistant, because amelogenin and amelin are recognized as “autoproteins” by the human defense system, and no allergic or immunologic reactions have been reported during ⬎10 years of use.13,24 The aim of the present study was to evaluate the clinical and radiographic efficacy of EMD and to compare it with self-hardening calcium hydroxide in DPC treatment on primary molars during a 12-month follow-up period. MATERIALS AND METHODS Design This study was approved by the Ethics Committee on Investigation at the Faculty of Dentistry of San Luis Potosi University, Mexico. It was designed as a randomized controlled clinical trial using the “splitmouth” variant. The various steps of the study followed the guidelines suggested by the CONSORT group25 for planning and reporting clinical trials in pediatric endodontics with the highest levels of evidence. Selection criteria Participants consisted of either gender of pediatric patients that exhibited 2 deeply decayed primary molars located on opposite sides of the mouth (maxillary or mandibular), restorable and with at least one-half of their root length, with clinical and radiographic data indicating treatment with direct pulp cappingh. Exclusion criteria were the presence of any clinical or radiographic sign or symptom of pulpitis or pulp necrosis, teeth about to be exfoliated, and patients diagnosed with a systematic or immunocompromising illness. Enrollment of participants was done by an independent, blind, and precalibrated experienced observer.
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Interventions All patients were treated at the clinic of the Pediatric Dentistry Postgraduate Program, Faculty of Dentistry of San Luis Potosi University, Mexico. A single operator carried out all of the operative procedures. Written informed consent was obtained from the participants’ parents. To standardize the technique, the complete operative procedure was practiced on extracted deeply decayed primary molars before the study. The operative technique is described briefly as follows. After anesthesia, the selected molar was isolated with a rubber dam and cleaned. Elimination of all peripheral decayed tissue was accomplished with a high-speed, #4 carbide round bur (Indeco/plus, Mexico City, Mexico). Then a standard and noncarious 1-mm pulp exposure was created with a #3 carbide round bur so that all exposures were of the same standard width; then the nature of the bleeding was reviewed: light red color and hemostasis in 2 or 3 minutes. The exposure was carefully washed with alternating irrigations of sterile saline and chlorhexidine solution (Consepsis; Ultradent Products, St. Jordan, UT) and dried gently with sterile cotton pellets. Immediately, the material was placed over the exposure with a round-head metallic applicator: EMD (Emdogain) in the experimental group and self-hardening calcium hydroxide (Dycal; Dentsply Caulk, Milford, ME) in the control group. Then the cavity was sealed with a cover of dentine adhesive (Singlebond; 3M Unitek, Monrovia, CA), another cover of glass ionomer (Vitrebond; 3M Espe, St. Paul, MN), both photopolymerized for 40 seconds; finally, a preformed metallic crown (3M Espe) was adapted and cemented (PCA; SS White, Gluocester, U.K.). Each patient was scheduled to be seen 1, 6, and 12 months after the operative procedures. During these appointments, the same observer who selected the patients carried out a complete clinical and radiographic review of the treated molars. Radiographs were taken using a film holder with the paralleling technique, with standardized exposure times and processing. It had been previously determined that the presence of any of the following signs or symptoms would be indicative of failure of the treatment: internal dentin resorption, spontaneous pain, gingival abscess (sinus tract), external root resorption, or pathologic mobility—all of them measured dichotomously. A total follow-up period of 12 months was selected on the basis of earlier studies6,21,26 that used periods from 60 to 120 days; findings from those studies show that at day 63, a dentin bridge was already observed. Reproducibility tests were undertaken at the beginning of the study to calibrate the evaluating observer. Unweighted kappa method was used for each sign or
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Table I. Number of successful and failed treatments per study group at the 3 evaluation times Follow-up 1 month Group of study EMD Ca(OH)2 Total*
6 months
12 months
Success
Failure
Success
Failure
Success
Failure
44 44 88
1 1 2
44 44 88
0 0 0
44 44 88
0 0 0
EMD, Enamel matrix derivative (Emdogain); Ca(OH)2, self-hardening calcium hydroxide (Dycal). *Both failures occurred during the first postoperative month.
symptom, obtaining good to excellent scores [from 0.7406 (95% CI 0.5471-0.9342; P ⫽ .000384) to 0.8976 (95% CI 0.7422-1.000; P ⫽ 1.37 e⫺08], according to Landis and Koch’s criteria.27 Sample size The sample was obtained with a nonprobabilistic method (consecutive cases), from the patient population that visited the clinics between July 2006 and February 2007. The total sample consisted of 45 pediatric patients, for a total of 90 treated primary molars. The sample size calculation was performed with an 80% power, on the basis of a reported incidence of internal dentin resorption.28 This is the sign that appears most frequently when DPC with calcium hydroxide is carried out on primary teeth1,7,8; therefore, it was considered as the outcome variable that would determine a real difference between the 2 materials. This difference, to be considered minimally clinically and statistically significant, was set at 20%. The sample size calculation used the formula for repeated measures. Randomization Selection of initial side of treatment in the mouth and allocation of DPC material for each molar were undertaken at random using number sequences generated by R 2.4.0 software). Two lists of random numbers were created, one corresponding to the capping material used in the initial operative appointment [odd number for EMD and even for Ca(OH)2] and the other to determine the side of the mouth that was treated at that appointment (odd for the left side and even for the right), following the split-mouth design; at the next appointment the other material on the opposite side was used. Each pair of numbers (from list 1 and list 2) corresponded to each patient. The operator was blind to the random number schemes until just before placing the materials. Blinding In this study, the participants, assessing observer, and analyst were blind regarding capping material
group assignation. Because Emdogain and Dycal each has recognizable characteristics, they could not be blinded to the operator. Statistical methods Outcome variables in this study were dichotomous. A clinical failure was recorded if the tooth presented any of these clinical or radiographic variables. Tooth type and location were also considered. Fisher exact test was used. A difference was considered to be significant if the probability that it occurred by chance alone was less that 5% (p ⬍ .05) in a 2-tailed test. R 2.4.0 software was used to perform the statistical analysis. RESULTS The recruitment period for eligible children was 7 months. Fifty-six subjects were recruited for this trial, and 11 were excluded. All of the 45 participants completed the follow-up according to the designed protocol. The descriptive analysis shows that gender distribution was 58% female and 42% male. Median age was 5.7 years (SD 1.01) for girls and 6.4 years (SD 1.16) for boys. The largest proportion was found in the 6-year group of both genders. There were no significant differences in age or gender between the study groups (P ⫽ .999). In total, 90 DPC treatments were performed (45 in the experimental group and 45 in the control group) and followed for 12 months. There were 88 successful treatments at the end of this period, with only 2 considered to be failures (1 per study group): a maxillary left first molar in the EMD group presented spontaneous pain, abnormal mobility, swelling, and a gingival abscess, and in the control group, a mandibular right second molar exhibited internal dentin resorption in the postoperative radiograph. Both teeth showed those abnormalities during the first follow-up month (Table I). Description of each outcome variable in each study group and during evaluation times is shown in Table II. There were no other adverse events reported. Regarding the number of treatments undertaken on each pri-
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Table II. Incidence of each outcome variable at 1, 6, and 12 months of follow-up Outcome variable Abscess Group of study EMD
Ca(OH)2
Mobility
IDR
Pain
PBR
Time
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
1 month 6 months 12 months 1 month 6 months 12 months
1 0 0 0 0 0
44 44 44 45 45 45
1 0 0 0 0 0
44 44 44 45 45 45
0 0 0 1 0 0
45 45 45 44 44 44
0 0 0 0 0 0
45 45 45 45 45 45
1 0 0 0 0 0
44 44 44 45 45 45
IDR, Internal dentin resorption; PBR, pathologic bone resorption. Other abbreviations as in Table I.
mary molar, the tooth receiving the most treatments was the mandibular left first molar, with 14 cases; the one with the least number of procedures was the maxillary right first molar, with only 9 cases. There were no significant differences as to the type of treated molar and localization (P ⫽ 1.000). On the basis of the results obtained in the analysis, statistical differences between the 2 treatment groups could not be found (P ⬎ .05). DISCUSSION The dental pulp is a highly vascular and innervated connective tissue that is capable of healing by forming hard-tissue barriers or dentin bridges after DPC.22,29 Innovative therapies have been used in an attempt to apply biologic modulators that have been identified during tooth and bone embryogenesis and cloned experimentally; these agents are intended to improve treatment modalities and induce tissue regeneration.30 Dental pulp capping has almost disappeared from the wide repertory of pulp treatments in primary teeth, because it is considered to be a compromising and risky procedure owing to its likelihood of producing internal dentin resorption26 and, with less frequency, pulp calcification, necrosis, and damage to the surrounding alveolar bone.1 Higher cell concentration of the primary pulp tissue could be the cause of these abnormalities; it is supposed that the mesenchymal cells become differentiated to odontoclastic cells in response to the capping material (calcium hydroxide), thereby causing internal root resorption.26 DPC has been limited to those cases where exfoliation of affected primary teeth is expected within 1 or 2 years. Moreover, an ideal material for DPC of primary teeth has not been completely accepted; although calcium hydroxide promotes healing and maintains the vitality of pulp tissue, harmful effects on the treated tooth or its periradicular tissues have been reported.1 Nor has there been a standardized DCP technique for primary teeth, such as those developed or suggested by experienced clini-
cians,3,31 that considerably improves the prognosis of treatment. In the present study, 2 capping materials were compared; these materials have different mechanisms of action. Calcium hydroxide is applied directly to the pulp tissue; because of its high alkaline pH, it produces a limited necrotic zone of superficial liquefaction necrosis that causes a mild irritation, promoting pulp cells to differentiate into new odontoblasts (also called odontoblast-like cells, odontoblastoids, or pseudodontoblasts) that place a mineralized dentin bridge on the pulp exposure.18 The newly formed hard tissue resembles secondary dentine from the very onset of the reparative process.10 On the other hand, EMD, because of its amelogenin and amelin-rich fraction, has the potential to induce a process that seems to imitate normal dentinogenesis; it clearly influences the odontoblasts and endothelial cells of the pulp capillary vessels to create a hard calcified barrier over the pulp exposure.19,21 It has been reported that enamel matrix proteins participate in differentiation and maturation of the odontoblastic cells, and when the pulp wound is exposed to EMD a substantial amount of reparative dentin-like tissue is formed in a process much resembling classic wound healing, with subsequent neogenesis of normal pulp tissues. The formation of new dentin starts from within the pulp at some distance from the exposure site.10 Also, EMD promotes an intracellular cyclic adenosine monophosphate signal in mesenchymal cells; this intracellular signal is followed by secretion of autocrine growth factors and a subsequent increased proliferation and maturation of extracellular matrix-secreting cells.14 EMD has been shown to induce expression of integrins in cultured fibroblasts, which play an important role in mesenchymal cell development and function.10 Three reasons can be mentioned to explain the high success rate obtained for both capping materials in the present study:
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1. Strict participant selection, both clinically and radiographically. One of the factors that greatly improves the prognosis of the DPC procedure is the absence of inflammation of the exposed pulp tissue2; this was meticulously observed during diagnostic and treatment phases. 2. Performing a careful operative technique based on recommendations from previous studies.3,21,31 All carious tissue was removed before DPC, because necrotic and infected dentin chips can impede healing of the exposure by causing further pulpal inflammation.3 On the other hand, standardization of exposure size was achieved using a 1-mm-diameter round bur in all of the interventions; this wide exposure had 3 purposes: to remove the inflamed or infected pulp tissue from the exposed area, to facilitate washing away carious or contaminated dentine debris, and to allow a closer contact between the capping material and the exposed pulp tissue.3,32 Limiting the width of pulp exposure may favorably influence the pulp-capping therapy, because the availability of odontoblast-like cells appears to be limited; larger exposures are also likely to generate a greater quantity of debris that could impair pulptissue healing.29 Moreover, 2 fundamental pediatric endodontic principles were observed: operating under conditions of absolute isolation and the constant maintenance of an aseptic operating field. Further precautions were avoiding clot formation on the exposed pulp,3 profuse rinsing of the exposure with chlorhexidine and sterile saline solutions, and immediate placing of the capping materials. 3. Microleakage was controlled to the utmost; this factor greatly affects the prognosis of pediatric pulp treatments.33 A bacteriometic seal permits pulp reparative activity to occur naturally beneath capping materials. It has been observed that bacterial microleakage reduces the odontoblast-like secretion of dentin bridges; this may lead to the development of postoperative complications if the bridge cannot protect the pulp from injury.29 A layer of glass ionomer was placed, together with a metallic crown restoration, which offers superior resistance to fracture and microleakage compared with IRM, glass ionomer, or Cavit.34 Few comparative studies have reported use of the same DPC materials. Olsson et al.21 carried out the procedure in 9 pairs of caries-free premolars scheduled for extraction for orthodontic purposes, with a 12-week postoperative observation period. In comparing results, we found some differences. The present study was undertaken in deeply decayed primary molars, and the follow-up time was longer. Additionally, Olsson et al.
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used Teflon discs fixed by wax to hold the capping materials, sealing the cavity with zinc oxide– eugenol cement and glass ionomer. For the same purpose, we placed a dentin adhesive and glass ionomer coats, restoring with a metallic crown. Regarding the observed results, they reported fewer postoperative symptoms in the EMD group, whereas we found no significant differences between our 2 groups in relation to incidence of postoperative signs or symptoms. Their immunohistochemical analysis exhibited new hard tissue, which partly replaced the EMD gel in the exposure site, and a larger amount of inflammatory tissue in relation to calcium hydroxide, which formed a hard mineralized bridge whose aspect was markedly different and of insufficient quality to act as a protective barrier. One of the goals of the present study was to reconsider the use of DPC on primary teeth as a less invasive alternative to pulpotomy, because DPC has potential clinical applications and shows promising results. Our recommendations that might improve the prognosis of DPC on primary molars are: 1) careful selection of cases based on a meticulous clinical and radiographic diagnosis; 2) operative procedures under absolutely aseptic conditions; 3) adequate exposure size; 4) disinfection of the exposed area with chlorhexidine and saline rinses; and 5) control of microleakage by placement of the dentine adhesive, glass ionomer, and preformed metallic crown. We conclude that there were no statistically or clinically significant differences between EMD (Emdogain) and self-hardening calcium hydroxide (Dycal) regarding the appearance of pathologic signs or symptoms when used as DPC materials on pulp exposures of 1 mm diameter in primary molars. Both capping materials showed a similar effectiveness in this pulp procedure, with a postoperative observation time of 12 months. On the basis of this study, we recommend the use of DCP treatment on primary molars as a standardized technique. The authors thank Dr. Carlos Garrocho-Sandoval for reviewing the manuscript and Norman Wahl for his assistance in editing the manuscript. REFERENCES 1. Fuks A. Pulp therapy for the primary and young permanent dentition. In: García-Godoy F, editor. Dental clinics of north america. Philadelphia: Saunders; 2000p. 578-81. 2. Yamamura T. Differentiation of pulpal cells and inductive influences of various matrices with reference to pulpal wound healing. J Dent Res 1985;64:530-40. 3. Kopel H. Considerations for the direct pulp capping procedure in primary teeth: a review of the literature. J Dent Child 1992;60:141-9. 4. Pereira C, Stanley HR. Pulp capping: influence of the site on pulp healing: histological and radiographic study in dogs’ pulp. J Endod 1981;7:213-23.
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22. Sabbarini J, Mounir M, Dean J. Histological evaluation of enamel matrix derivative as a pulpotomy agent in primary teeth. Pediatr Dent 2007;29:475-9. 23. Papagerakis P, MacDougall M, Hotton D, Baillieul-Forestier I, Oboeuf M, Berdal A. Expression of amelogenin in odontoblasts. Bone 2003;32:1-130. 24. Wilson T. Safety testing of Emdogain. In: Wilson T, editor. Periodontal regeneration enhanced. Chicago: Quintessence; 1999. p. 23-5. 25. Altman D, Schulz K, Moher D, Egger M, Davidoff F, Elbourne D. et al. The revised CONSORT statement for reporting randomized trials: explanation and elaboration. Ann Intern Med 2001;134:663-94. 26. Cehreli Z, Turgut M, Olmez S, Dagdeviren A, Atilla P. Short term human primary pulpal response after direct pulp capping with fourth-generation dentin adhesives. J Clin Pediatr Dent 2000;25:65-71. 27. Sackett D, Haynes R, Guyatt G, Tugwell P. El examen clínico. In: Sackett D, editor. Epidemiología clínica. Buenos Aires: Panamericana; 1997. p. 43-5. 28. Rabinowitch BZ. Internal resorption. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1972;33:263-82. 29. Murray PE, Hafez A, Smith A, Windsor L, Cox F. Histophometric analysis of odontoblast-like cell numbers and dentine bridge secretory activity following pulp exposure. Int Endod J 2003;36:106-16. 30. Britto LR, Jiang J, Vertucci FJ. The role of biological modulators in endodontic therapy. Rev Fac Odontol Bauru 2002;10:201-8. 31. Becerra L, Campos A. Proteçao pulpar direta. In: Becerra L, editor. Odontopediatría. Bases científicas para la práctica clínica. Sao Paulo: Artes Médicas; 2005. p. 537-66. 32. Schröder U, Szpringer-Nodzak M, Janicha J, Waciúnka M, Budny J, Mlosek K. A one-year follow-up of partial pulpotomy and calcium hydroxide capping in primary molars. Endod Dent Traumatol 1987;3:304-6. 33. Guelmann M, Fair J, Turner C, Courts, F. The success of emergency pulpotomies in primary molars. Pediatr Dent 2002;24: 217-20. 34. Dittel M, Garrocho A, Méndez V, Hernández F, Pozos A. Grado de sellado marginal de materiales de obturación temporal en molares primarios con pulpotomía: estudio in vitro. Rev Odontol Mex 2006;10:83-7. Reprint requests: Dr. Amaury de Jesús Pozos Guillén Facultad de Estomatología Universidad Autónoma de San Luis Potosí Av. Dr. Manuel Nava #2 Zona Universitaria, C.P. 78290 San Luis Potosí México. [email protected]