85644981

PEDIATRIC DENTISTRY

llinic al Article

V 3 5 ; NO 1

JAN :' EEB 13

RETROSPECTIVE RECORD REVIEW

Reinforced Zinc Oxide-Eugenol Pulpotomy: A Retrospective Study E.K. Hui-Derksen, DDS, MS' • Chiung-Fen Chen, DDS, MS^ • Robert Majewski, DDS, MS^ • Ruwaida G.H. Tootia, BChD, PhD" • James R. Boynton, DDS,

Abstract: Purpose: The purpose of this retrospective study was to evaiuate puipotomies eompieted without the use of a fixative, preservative, or astringent agent prior to piaeement of a reinforeed zinc oxide-eugenol (ZOF) sub-base in the puip chamber and subsequent restoration. Methods: Ciinicai and radiographie data were collected from a private pédiatrie dentai offiee in Toronto, Ontario, Canada. The pulpotomy teehnique used invoived: amputation of coronal pulp: radicuiar hemostasis via pressure with dry cotton peiiet: piaeement of ZOE into the puip ehamber: and restoration with stainless steel erown or amalgam. Results: One-hundred-ninety primary moiars in 116 chiidren (foiiow-up=6-94 months: mean=35.8 months) met the inclusion eriteria. The radiographie, dinicai, and overaii sueeess rates were approximately 95%, 97%, and 94%, respeetiveiy. The most frequentiy observed pathoiogie puipai response was fureation radioiueency (N=7, ~4%). The patient's age at time of puipotomy, restoration type, tooth type, arch, and ioeation of treatment (in-offiee vs gênerai anesthesia) were not statistieaiiy significant factors influendng the success of the reinforced ZOF puipotomy technigue.

Conclusion: The success rates indicate that the reinforced zinc oxide-eugenoi puipotomy technique may be an aeeeptabie treatment modaiity for primary moiars requiring vitai puip therapy (Pediatr Dent 2013:35:43-6) ReeeivedJune 20, 2011 / Last Revision November 13, 2011 i Aeeepted November 23, 2011

KEYWORDS: PULPOTOMY, ZINC OXIDE, EUGENOL, DENTITION, PRIMARY

When caries removal results in a carious or mechanical pulp exposure, a pulpotomy is performed in a primary tooth with extensive decay but without evidence of radicular pathology.'

The coronal pulp is amputated, and the remaining vital radicular pulp tissue is treated with a medicament such as formocresol.

After the pulp chamber is filled with zinc oxide-eugenol (ZOE) or another suitable base, the tooth is given a restoration that seals it from leakage.

Formocresol is considered the "gold standard" of all pulpotomy agents.' Due to concerns over mutagencity, potential carcinogenicity, and immune sensitization of formocresol,'•'' however, alternative medicaments have been proposed, including: calcium hydroxide^; glutaraldehyde*"; ferric sulfate'; electrocautery"; lasers'*; collagen solutions; bone morphogenic proteins'"; and mineral trioxide aggregate.- In the search for alternatives to formocresol, some practitioners have simply eliminated the initial medicament step and placed the ZOE base into the pulp chamber after achieving radicular pulpal hemostasis with pressure.

ZOE was the first agent to be used for preservation (minimal devitalization, noninductive)" and is currently used as a base material in pulpotomy. Some studies have shown that teeth treated with a pulpotomy with a ZOE base demonstrated internal résorption and inflammation at the pulpotomy's amputation site.'^'^ It has been assumed that internal résorption is associated with eugenol and, when ZOE is used as a sub-base following pulpotomy, eugenol directly contacts with the vital tissue and causes moderate to severe inflammatory response.

Products such as IRM and ZOE B&T (both Dentsply Caulk, Milford, Del., USA) are reinforced ZOE materials with improved mechanical properties. Reinforced ZOE contains polymethyl methacrylate, zinc oxide, acetic acid, and eugenol.

Euks et al. found that 73% of pulpotomized primary teeth of baboons treated with IRM (group 1) only presented with mild or no inflammation vs teeth treated with ferric sulfate (58%; group 2) and formocresol (48%; group 3) prior to placement of an IRM base within 8 weeks."" No statistically significant differences were noted among the 3 groups for degree of inflammation, abscess, or inflammatory root résorption.

A pédiatrie dentist in private practice in Toronto, Ontario, Canada, has been employing a pulpotomy technique using pressure hemostasis followed by placement of ZOE B&T in the pulp chamber for a number of years. This private practitioner has reported anecdotal success, but no study could he found in the literature that analyzed this technique.

Therefore, the purpose of this retrospective study was to evaluate puipotomies completed without the use of a fixative, preservative, or astringent agent prior to placement of a reinforced zinc oxide-eugenol (ZOE) sub-base in the pulp chamber and subsequent restoration.

Methods A private pédiatrie dental office in Toronto has exclusively used ZOE B&T after achieving radicular pulpal hemostasis within 60 seconds with pressure from a dry cotton pellet. Permission to conduct this study was obtained from the private practitioner.

This study was approved by the Health Sciences Institutional Review Board of the University of Michigan, Ann Arbor, Mich. ^Dr. Hui-Derksen is in private practice in Vancouver, British Columbia, Canada. ^Dr Clinical and radiographie data were collected from record Ghen is a clinical lecturer, and ^Dr. Boynton is a elinical assistant professor and direc- review. Patients who presented between 1997 and 2001 were tor, pédiatrie dentistry, both at Department of Orthodontics and Pédiatrie Dentistry. considered to be potential candidates, the records of whom were Sehool of Dentistry. University of Michigan; 'Dr. Majewski is a elinical director, pédiatrie dentistry. Mott Children's Health Center, and adjunct associate professor. Department reviewed and recruited for this study if the following criteria of Orthodontics and Pédiatrie Dentistiy. School of Dentistry. University of Miehigan; and were met. The patient had to have: *Dr. Tootia is a pédiatrie dentist, allin Ann Arbor, Mich.. USA. 1. at least 1 primary molar which had undergone pulpoCorrespond with Dr. Boynton at jboynton@umich. edu tomy; THE REINEORCED ZINC OXIDE-EUGENOL PULPOTOMY

43

PEDIATRIC DENTISTRY

V 35 ! NO 1

JAN ! EEB 13

2.

no documented clinical symptoms or evidence of pulpal degeneration, including swelling or presence of a sinus tract before the pulpotomy; 3. a tooth restored with a stainless steel crown (SSC) or amalgam at the same visit; and 4. returned for at least 1 recall visit following the pulpotomy.

To be qualified, radiographs had to have properfilmdensity and contrast for radiographie diagnosis and displayed a minimum of 4.0 mm of the furcation area.

All primary molars were treated by one practitioner with the following technique: rubber dam isolation; slow-speed caries removal; and upon pulp exposure, coronal access was performed with a high-speed fissure bur with water spray. The coronal pulp tissue was amputated with a round bur in a slow-speed handpiece. Radicular pulpal hemostasis was obtained by applying pressure with a dry cotton pellet to the pulpal stumps. If hemostasis was achieved within 60 seconds, the pulp chamber was filled with ZOE B&T. The teeth were restored with either SSCs or amalgam.

Data collected for each patient during the records review included: (1) gender; (2) age at time of pulpotomy treatment; (3) tooth type; (4) restoration type; (5) arch; (6) follow-up time; (7) location of treatment; (8) radiographie findings; and (9) clinical findings. Clinical categories developed for record review included: no chart entry; fistula; abscess/swelling; pain; mobility; lost restoration; and missing tooth.

The absence of clinical notation was interpreted to be the absence of clinical signs or symptoms. The pulpotomy was defined as a clinical failure when the tooth was documented as having: prolonged spontaneous pain; tenderness to percussion; abscess formation; pathological mobility;fistula;or swelling.

All radiographs in records were evaluated by one evaluator.

The criteria used to describe radiographie findings included: unremarkable; external root résorption; internal root résorption; intraradicular radiolucencies; periapical radiolucencies; and pulp canal obliteration. The pulpotomy was defined as a radiographie failure when one or more of the aforementioned signs were detected, although suspected areas of internal root résorption which were undetectable on subsequent radiographs were not classified as internal root résorption.

All clinical chart reviews and radiographie evaluations were completed by the same investigator. Radiographie diagnostic agreement was determined against a single experienced pédiatrie dentist by independent evaluation of 50 radiographs of previously pulpotomized primary teeth. The 50 radiographs used to determine rater reliability were not a subset of the study population.

Data were analyzed using the SPSS 15.0 software (SPSS Inc, Chicago, 111., USA). Preliminary analyses consisted of testing radiographic successes by each variable using chi3 ys, 10 mos square tests of independence. Clinical, radiographic, and overall successes were also tested with each variable using the chi-square test and Fisher's exact test.

Results Fifty radiographs were independently read by 2 investigators, and inter-rater reliability was determined. The kappa statistic indicated highly significant reproducibility between the 2 examiners, with a measurement of agreement ofO.893.

44

THE REINFORCED ZINC OXIDE-EUGENOL PULPOTOMY

The final study sample consisted of 116 children (62 females, 52 males, and 2 unrecorded) with a mean age at the time of pulpotomy of 77.3 months (±21.7 SD; range=33-134 months). A total of 190 primary teeth (first molars=103, second molars=87, maxillary molars=86, mandibular molars=104) met the inclusion criteria. The follow-up time ranged between 6 to 94 months, with a mean of 35.8 months (±21.7; Table 1).

The number of radiographie observations per pulpotomized tooth ranged from 1 to 8; the mean was 2.1 radiographie observations per tooth (±1.2). At the time of the pulpotomy, 177/ 190 (-93%) teeth were restored with a SSC and 13/190 (-7%) teeth were restored with an amalgam restoration. Of the 190 teeth in the study, 170 (-90%) were treated in-office and 20 (-11%) were treated in the operating room.

The clinical success rate was 185/190 (-97%), with a followup time ranging from 6 to 94 months. Clinically successful teeth were followed for a mean time of 36.4 (±21.8) months, with a median follow-up time of 34 months. Clinical failures were attributed to abscess (N=3) and lost SSC (N=2). Clinical failures were observed between 9 to 16 months, with a mean of 11.8 months (±3.0).

The radiographie success rate was 181/190 (-95%), with a follow-up time ranging from 6 to 94 months and averaging 36.7 months (±21.6). The earliest observed radiographie failures were observed at 9 months, with 51 months being the latest observed failure and averaging 16.8 months (±13.3). Two teeth presented with more than one radiographie finding. The most common radiographie sign was furcation radiolucency (N=7; Table 2). Interestingly, internal résorption was initially seen in 3 additional teeth, but these were radiographically normal upon Table 1 .

Follow-up time (mos)

6-12 13-24 25-36 37-48 >48

RÄDt0GRi4PMIC OBSËRVATJONS Success (no. of teeth)

Failure (no. of teeth)

Success rate during observation period (%)

59 104 61 59 113

6

91 % 100 100 99

m «

, .1

'

* SSC=stainless steel crown.

Clinical pathology :tion radiolucency and periapical radioiucency SSC

12

External résorption and furcarion radiolucency Furcation radiolucency Furcation radiolucency Furcation radiolucency Furcation radiolucency Furcation radiolucency Internal résorption riapical radiolucency None

Abscess None Lost SSC Abscess None None Norn None None '^ Lost SSC Abscess :

PEDIATRIC DENTISTRY

subsequent follow-up radiographs. Pulp canal obliteration was not observed in any of the teeth.

Radiographic and clinical findings were combined to provide an overall success rate, which was 179/190 (-94%), with a followup time ranging between 6 to 94 months; successful teeth had a mean follow-up time of 37 months (±21.6). Three teeth presented with both radiographie and clinical signs of failure; all other failed teeth had either a radiographie or clinical sign of failure (Table 2). Overall, the mean follow-up time to failure was 16.2 months (±12.0).

Three of 86 (-4%) maxillary molars had failed, while 8 of 104 (-8%) mandibular molars failed. Although mandibular teeth failed twice as often, no statistical difference was found between maxillary and mandibular molars (P<.35). Males accounted for the most failures (N=10); therefore, gender was found to be significant in the overall success of the ZOE pulpotomy technique (P<.002). Age {P>.87), restoration type (7^.55), tooth type (P<.7G), arch {Pi.^'i), and location of treatment (P<.10) were not significant factors in the overall, radiographie, and clinical successes of the reinforced ZOE pulpotomy technique.

Discussion To date, few studies have evaluated the success of ZOE pulpotomies, whether reinforced or plain. Chien et al., compared ZOE pulpotomies to ferric sulfate/ZOE pulpotomies and found the success rate to be 100% for both materials.'^ Follow-up time in this clinical study, however, was 3 months. Because Chien et al., used plain ZOE as a base material, comparing their results to the present investigation may be limited, as reinforced ZOE was used in this study.

Erdem et al., reported a 68% success rate at the 24-month follow-up using a ZOE pulpotomy technique; all teeth were restored with amalgam, and the subjects' ages were between 5 and 7 years old."* The final restoration of pulpotomized primary molars is a contributing factor to pulpotomy failure," which may account for some of the differences in the results. Also, in Erdems' study, Kalzinol was the reinforced-ZOE material used; this material is reinforced with 2% by weight polystyrene vs ZOE B&T, which is reinforced with 20% polymethyl methacrylate.^" The type of ZOE reinforcement has been shown to affect the material's physical properties. Kalzinol has been shown to display signs of disintegration after 8 weeks of exposure to a buffered phosphate solution, while IRM showed no noticeable changes after 6 months.^' Also, aged Kalzinol is less cytotoxic than aged IRM.^^ The properties of differently reinforced ZOE formulations could account for the different success rate observed in the present study.

This study's high clinical success rate may be attributed to the strict diagnostic criteria on pulpal status used by this practitioner, who reports progressing to pulpectomy or extraction if bleeding of the radicular pulp is not arrested within 60 seconds.

Some authors argue that the main reason for pulpotomy failure is a failure to accurately diagnose pulpal status.^^ Some studies have suggested that the ability to achieve hemostasis with a dry cotton pellet after pulpal amputation is indicative of the health of the radicular pulpal tissue."'''-' Inability to achieve hemostasis or prolonged bleeding after pulpal amputation is considered by some to be a sign of irreversible pulpitis.^*"' " Furthermore, a hyperemic, inflamed radicular pulp is a contraindication for vital pulp therapy.^* This practitioner's use of the ability to achieve pulpal hemostasis within 60 seconds is perhaps an important factor in the success of the reinforced ZOE pulpotomy technique.

Furcation radiolucency was the most common radiographie finding in this study. Interestingly, furcation radiolucencies have not been reported in studies of ZOE pulpotomies.'''•"•''''^'Hicks

V 35 I NO 1

|AN : FEB 13

et al, reported a similar rate of furcation radiolucencies (-4%) in a retrospective study of primary molar pulpotomies, with a follow-up period of 24 to 87 months.'' In their study, hemostasis was achieved by pressure with a dry cotton pellet followed by placement of equal parts of ZOE paste and full-strength formocresol into the paste.^' Similarly, Thompson et al., also reported inter-radicular bone destruction in approximately 3% of teeth treated with formocresol pulpotomy in which the formocresoldampened cotton pellet was used to medicate both the pulp and achieve hemostasis.™ Overall, the reported rate of furcation radiolucencies in this study is low (-4%, 7/190) and similar to reported ranges in retrospective studies of formocresol pulpotomies.

The low frequency observed of internal résorption in this study may be explained by the fact that this study used reinforced ZOE (ZOE B&T) rather than regular ZOE. One may speculate that the addition of polymethyl methacrylate in reinforced ZOE may decrease the effects of eugenol, which is thought to be an irritant to pulp tissue. This is supported by Cook and Taylor, who found ZOE B&T to be less irritating than pure ZOE cement in tissue implants."

The basic composition of ZOE is a combination of zinc oxide particles embedded in a matrix of zinc oxide eugenolate.

When zinc oxide is mixed with eugenol, a chelation reaction occurs, forming zinc eugenolate.'^ This substance is not stable in the presence of water. The surface of the set material readily undergoes hydrolysis with the release of free eugenol, which remains in the mass and can act as an irritant.'" Smith et al., claimed that internal résorption is associated with eugenol and, when ZOE is used as a sub-base following pulpotomy, eugenol directly contacts with the vital tissue and causes moderate to severe inflammatory response.^'' Although low concentration eugenol exerts anti-inflammatory and local anesthetic effects on the dental pulp tissue, a high concentration of eugenol is cytotoxic.'^ The concentration of eugenol should not be too high, for reason of biocompatibility. Hansen et al. observed radiographie internal résorption in 6/14 teeth (43%) treated with ZOE.'"* Histological studies of ZOE pulpotomies indicate that internal résorption occurs near areas of severe inflammation.'^ Internal résorption was observed in 4 teeth (-2%, 4/190) in this study. Interestingly, 3 of 4 teeth were radiographically normal upon subsequent follow-up radiographs and were not included as failures. Although areas of internal résorption in primary teeth may progress slowly or arrest, it seems unlikely that the resorptive process would reverse and the tooth would revert to a normal radiographie appearance upon subsequent films. We speculate that these detected areas of internal résorption that "resolved" were actually initially misdiagnosed, possibly due to deviated film angulations or radiographie artifacts.

ZOE B&T material is "contraindicated for direct application to dental pulp tissue (direct pulp capping)," per the instructions for use provided by the manufacturer."" This is likely due to eugenoFs irritation when contacting Inflamed pulp tissue. ZOE B&T, as used in this study, was directly applied to primary pulp tissue; however, it was not likely placed on chronically inflamed pulp tissue (as would be expected in a direct pulp capping situation). The effects of direct placement of reinforced ZOE on nonchronically inflamed vital primary pulp tissue, adjacent to a site of pulp amputation (as would be expected in the vital pulpotomy technique), should be histologically studied before this procedure can be recommended.

Gender was found to be a significant variable in this study.

No study to date has found a relationship between gender and pulpotomy failure. The explanation for the differences found between males and females in this study is difficult to postulate and seems most likely attributed to chance.

THE REINFORCED ZINC OXIDE-EUGENOL PULPOTOMY

45

PEDIATRIC DENTISTRY

V 35 ,' NO 1

JAN i FEB 13

Several limitations exist in this study due to its retrospective design. All data collected were dependent on chart entries (which may have been incomplete or inaccurate) or by radiograph interpretation. A single evaluator evaluated all clinical chart entries and radiographs. Intra-rater reliability was not determined. Because of these major limitations, we feel additional retrospective studies should be completed to validate these results. Future prospective clinical studies and histological analyses should also be completed before recommending this technique.

15.

16.

17.

Conclusion Based on this study's results, the following conclusion can be made: 1. Achieving pulpal hemostasis within 60 seconds using a dry cotton pellet, followed by application of polymethyl methacrolate-reinforced ZOE, may be a successful treatment modality for primary molars requiring vital pulp therapy.

References 1. American Academy on Pédiatrie Dentistry Clinical Affairs Committee, Pulp Therapy Subcommittee, Council on Clinical Affairs. Guideline on pulp therapy for primary and immature permanent teeth. Reference Manual 2010-2011.

Pediatr Dent 2010;32:194-201.

2. Fuks AB. Pulp therapy with new materials for primary teeth: New directions and treatment perspectives. Pediatr Dent 2008;30:211-9.

3. Zarzar PA, Rosenblatt A, Takahashi CS, Takeuchi PL, Costa Junior LA. Formocresol mutagenicity following primary tooth pulp therapy: An in vivo study. J Dent 2003;31: 479-85.

4. Casas M, Kenny D, Judd P, Johnston D. Do we still need formocresol in pédiatrie dentistry. J Can Dent Assoc 2005; 71:749-51.

5. Schroder U. A 2-year follow-up of primary molars pulpotomized with a gentle technique and capped with calcium hydroxide. Scand J Dent Res 1978;86:273-8.

6. Davis MJ, Myers R, Switkes MD. Glutaraldehyde: An alternative to formocresol for vital pulp therapy. J Dent Child 1982;49:176-80.

7. Fuks AB, Holán G, Davis JM, Eidelman E. Ferric sulfate versus dilute formocresol in pulpotomized primary molars: Longterm follow-up. Pediatr Dent 1997; 19:237-30.

8. Shaw DL, Sheller B, Barrus BD, Morton TH. Electrosurgical pulpotomy: A 6-month study in primates. J Endod 1987;13:500-5.

9. Saltzman B, Sigal M, Clokie C, Rukavina J, Titley K, Kulkarni GV. Assessment of a novel alternative to conventional formocresol-zinc oxide eugenol pulpotomy for the treatment of pulpally involved human primary teeth: Diode lasermineral trioxide aggregate pulpotomy. Int J Paediatr Dent 2005;15:437-47.

10. Jepsen S, Albers HK, Feiner B, Tucker M, Rueger D. Recombinant human osteogenic protein-1 induces dentin formation: An experimental study in miniature swine. J Endod 1997;23:378-82.

11. Ranly DM. Pulpotomy therapy in primary teeth: New modalities for old rationales. Pediatr Dent 1994;l6:403-9.

12. Berger JE. Pulp tissue reaction to formocresol and zinc oxideeugenol. J Dent Child 1965;32:13-28.

13. Boiler RJ. Reactions of pulpotomized teeth to zinc oxide and formocresol-type drugs. J Dent Child 1972;39:298-307.

14. Hansen HP, Ravn JJ, Ulrich D. Vital pulpotomy in primary molars: A clinical and histologie investigation of the effect of

46

THE REINFORCED ZINC OXIDE-EUGENOL PULPOTOMY

18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

32.

33.

34.

35.

36.

zinc oxide-eugenol cement and Ledermix. Scand J Dent Res 1971;79:13-23.

Magnusson B. Therapeutic pulpotomy in primary molars: Clinical and histological follow-up. II. Zinc oxide-eugenol as wound dressing. Odontol Revy 1971;22:45-54.

Fuks AB, Eidelman E, Cleaton-Jones P, Michaeli Y. Pulp response to ferric sulfate, diluted formocresol, and IRM in pulpotomized primary baboon teeth. J Dent Child 1997;64:254-9.

Chien MM, Setzer S, Cleaton-Jones P How does zinc oxideeugenol compare to ferric sulphate as a pulpotomy material?

SADJ 2001;56:130-5.

Erdem AP, Guven Y, Balli B, et al. Success rate of mineral trioxide aggregate, ferric sulfate, and formocresol puipotomies: A 24-month study. Pediatr Dent 2011;33:165-70.

Holan G, Fuks AB, Ketlz N. Success rate of formocresol pulpotomy in primary molars restored with stainless steel crown vs amalgam. Pediatr Dent 2002;24:212-6.

Naoum HJ, Chandler NP. Temporization for endodontics.

Int Endod J 2002;35:964-78.

Owadally ID, Pitt Ford TR. Effect of addition of hydroxyapatite on the physical properties of IRM. Int Endod J 1994; 27:227-32, Chong BS, Owadally ID, Pitt Ford TR, Wilson RE Cytotoxicity of potential retrograde root-filling materials. Endod DentTraumatol 1994;10:129-33.

Baume LJ. Diagnosis of diseases of the pulp. Oral Surg Oral Med Oral Pathol 1970;29:102-16.

Waterhouse PJ, Nunn JH, Whitworth JM, Soames JV. Primary molar pulp therapy: Histological evaluation of failure.

IntJ Paediatr Dent 2000;10:313-21.

Dannenburg JL. Pedodontic endodontics. Dent Clin North Am 1974; 18:367-77.

Guelmann M, Fair J, Bimstein E. Permanent versus temporary restorations after emergency puipotomies in primary molars. Pediatr Dent 2005;27:478-81.

McDonald RE, Avery DR, Dean JA Ralph E. McDonald, David R. Avery, and Jeffrey A. Dean. Treatment of deep caries, vital pulp exposure, and pulpless teeth. In: McDonald RE, Avery DR, eds. Dentistry for the Child and Adolescent.

9th ed. Maryland Heights, Mo: CV Mosby Co; 2011:343-65.

Fuks AB. Current concepts in vital primary pulp therapy.

EurJ Paediatr Dent 2002;3:115-20.

Hicks MJ, Barr ES, Flaitz CM. Formocresol puipotomies in primary molars: A radiographie study in a pédiatrie dentistry practice. J Pedod 1986;10:331-9.

Thompson KS, Seale NS, Nunn ME, Huff G. Alternative method of hemorrhage control in full strength formocresol pulpotomy Pediatr Dent 2001;23:217-22.

Gook DJ, Taylor PP. Tissue reactions to improved zinc oxideeugenol cements, J Dent Child 1973;40:199-207.

Markowitz K, Moynihan M, Liu M, Kim S. Biologic properties of eugenol and zinc oxide-eugenol: A clinically oriented review. Oral Surg Oral Med Oral Pathol 1992;73:729-37.

Johnson BR, Witherspoon DE. Periradicular surgery. In: Cohen S, Burns RC. Pathways of the Pulp. 9th ed. St. Louis, Mo: Mosby; 2006:756-7.

Smith NL, Seale NS, Nunn ME. Ferric sulfate pulpotomy in primary molars: A retrospective study. Pediatr Dent 2000; 22:192-9.

Magnusson BO. Therapeutic puipotomies in primary molars with the formocresol technique: A clinical and histological follow-up. Acta Odontol Scand 1978;36:157-65.

Dentsply Caulk. ZOE B&T directions for use. Available at: "http://www.caulk.com/assets/pdfs/products/507100_ ZoeB%26T_dfu.pdf". Accessed January 3, 2013.

Copyright of Pediatric Dentistry is the property of American Society of Dentistry for Children and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.