Pédiatrie Dentistry

Zinc oxide-eugenol pulpotomy and stainless steel crown restorationof a primary molarTheodore P, Croll* / Constance M. Killian* *

The most dtirable and reliable method of retaining a primary molar in the motith aftera pulpotomy procedure is complete-coverage restoration with a preformed stainlesssteel crown. This paper describes a method for performing pitlpotomy and stainlesssteel crown restoration of a primary molar. Neither formocresol, ghiteraldehyde, norcalcium hydroxide is tised during the pulpotomy phase of the treatment.(Quintessence Int 1992:23:383-388.)

Introduction

Informal surveys of general dentists reveal that manywho treat children seldom use stainless steel crownsfor primary molars. Some dentists do not even havepreformed stainless steel crown kits in their office sup-ply inventory. When dentists are queried as to whythey are reltictant to use stainless steel crowns, theusual response is that the dental school experience inpédiatrie dentistry casts a negative light on such "ad-vanced" concepts as stainless steel crowns. Pédiatriedentists, especially those in nonQuoridated areas orother regions with a high prevalence of caries, wouldbe severely hampered in treating eotnplex carious le-

sions or malformed or severely traumatized primarycanines and molars if preformed stainless steel crownswere not availahle.

While the debate continues over the hest type ofintrapulpal space medication for use during pulp-otomy procedures for primary teeth, a surprisinglysimple method of pulpotomy has received httle atten-tion. However, the method has proved most valuableand reliable in clinical use over the past 20 years.

This paper documents a step-hy-step procedure forrestoration of a pulpally involved primary first molarusing a thick paste of zinc oxide-eugenol alone as thepulpal space obturation material. The pulpotomy isfollowed hy immediate placement of a custom-adapted, preformed stainless steel crown.

* Private Practice, Pédiatrie Dentistry, Doyiestown, Pennsyl-vania; Clinica) Associate Professor, Department of PcdiatricDentistry, University of Pennsylvania, School of DentalMedieine; Adjunct Professor, Department of Pédiatrie Dentis-try, University of Texas, Healtb Science Center at Houston{Dental Branch),

** Private Practice, Pédiatrie Dentistry; Doyiestown, Pennsyl-vania; Clinical Assistant Professor, Department of PédiatrieDentistry, University ol Pennsylvania, School of DentalMedicine,

Address all correspondence toDrT, P. Croll, Georgetown Commons.Suite 2, 708 Shady Retreat Road, Doylestowu, Pennsylvania18W1,

Technique

The zinc oxide-eugcnol pulpotomy and stainless steelcrown procedure is performed as shown in Figs 1 to 17.

Discussion

Prospective success of a pulpotomy begins during thetreatment-planning phase of the procedure. If carefulcriteria are used to evaluate the tooth for which pulp-otomy is planned, the prognosis for long-term successis better.

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Fig 1 Primary first moiar with severe carious destruction.After appropriate loeai anesthetic is administered, rubberdam is placed.

Fig 2 A iarge, inuerted-cone. water-cooled carbide burrapidly reduces the occiusal surface by 2 to 3 mm.

Fig 3 A sterile, water-cooled carbide bur is used to re-move caries and enter the pulp cbamber. A sterile, siow-speed round bur débrides aii pulpai tissue from thechamber to the level of the root canai openings.

Fig 4 A steriie cotton pellet is compressed into the pulpchamber and retained until residuai hemorrhage of radicu-lar pulpal tissue has ceased.

Fig 5 iHemostasis is achieved, and the pulp chamber isready for placement of fhe restorative material.

Fig 6 A thick mix of pure zinc oxide-eugenoi cement iscompressed gently into the chamber and permitted to hard-en. Reinforced zinc oxide-eugenol paste is not used.

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Fig 7 Axial coronal preparation is performed with a water-coded, coarse diamond bur. The wooden wedge protectsinterproximal gingivai tissue.

Fig 8 After the tooth has been reduced axially, maintainingtooth form in miniature, axio-occlusal line angles arerounded.

Fig 9 The finished preparation is shown from the occlusalview. Note the mesial and distai spacing and the axiai scal-loping to increase cement-tooth structure interface.

Fig 10 (mirror view) A crown with oimensions that wiii repli-cate the original coronai form in aii spatial reiationships isselected. Contacts are reestabiished, and original marginalridge heights are duplicated.

Fig 11 A spoon excavator or cleoid-discoid is used toremove the crown form after try-in. Note the mesial décal-cification lesion on the adjacent second molar. That lesionwili be trimmed smooth and the surface treated with topicalfluoride solution.

Fig 12 A heatless stone is used to establish correct coronallength. Crown-cutting scissors are much less precise formarginal cutting.

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Fig 13 Flat-edged crimping pliers are used to crimp tbeedge of tbe margin so tbat the finisbed margin can engagethe undercut of ttie cervical buige.

Fig 14 A customized croviin form, ready for cementation,is compared to the preformed crown as suppiied by themanufacturer.

Fig 15 After a creamy mixture of polycarboxylate cementis pieced within the crown carefully, to avoid trapping air,the crown is seated with firm pressure appiied with a mirrorhandle. Glass-ionomer luting cement can also be used.

Fig 16 Excess cement is removed with sharp band instru-ments, such as a sealer or a cleoId-discoid, or an ultrasonicscaier. Excess proximal cement can be dislodged withknotted dental tape.

Fig 17 The finished crown.

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Fig ISa Another primary first molar is shown 7 years aflerzinc oxide-eugenoi pulpotomy and piacement of a stain-less steel crown.

Fig 18b The pulpotomy and crown are shown radiographic-aiiy (left) 4 years after treatment and (right) 7 years post-operative i y.

Contraindications for vital pulpotomy in a primarymolar include history of spontaneous pain; sensitivityto perctission; mobility of the tooth: presence of sinustract, indicating dcntoalveolar abcess; and radiographieevidence of pathosis. Any of these signs or symptomsindicate that the inflammatory process has progressedbeyond the confines of the involved tooth into adja-cent tissues. Likelihood for a successful pulpotomy insuch cases is poor.

During preparation of the tooth, rubber dam is usedto isolate the tooth from surrounding soft tissues andsaliva. Exposed pulpal tissues are therefore protectedfrom salivary contamination.

Use of formocrewl as a pulpal tissue fixative is con-troversial.'~' Both in vitro and in vivo studies have dem-onstrated that form ocre so I placed in contact withvital pulpal tissue is distributed systemically.'"^ For-mocresol with '""C-labeled formaldehyde has beenused in pulpotomies and subsequently recovered inliver, kidney, heart, spleen, and lung tissue of treatedanimals.̂

GI Uteraldehyde has been studied as an alternativeto formocresol for pulpal fixation.''"' However,gluteraldehyde placed in contact with pulpal tissue isalso distributed systemicalJy.̂ In addition, a clinicalsludy of gluteraldehyde pulpotomies did not reporta success rate equal to that demonstrated by formo-cresol.'" Further studies of the effect of concentrationand exposure time of gluteraldehyde on pulpal tissuehave been recommended to ascertain clinical usefulnessof gluteraldehyde."

In an effort to avoid formocresol and gluteral-

dehyde, pure ealcium hydroxide has been used as apulpotomy medication. Too often, however, rapidinternal resorplion of the root and crown results,'""so that method is not recommended.

The concept of nonaldehyde pulpal therapy forprimary teeth has recently been described. Yacobi etal'* reported a technique for pulpectomy that usesonly zinc oxide-eugenol paste.''' At 12 months, theirrate of success was the same as that reported forformocresol pulpotomy. Over the past decade, wehave performed zinc oxide-eugenoi pulpotomies forprimary molars without using any other agent andhave had similar chnical results. In light of concernsregarding safety of aldehyde compounds, zinc oxide-eugenol pulpotomy should be considered as an alter-native to formocresol or gluteraldehyde pulpotomiesfor treatment of certain primary molars.

A stainless steel crown is Ihe restoration of choicefor a tooth that has undergone pulpotomy. Ideally, thecrown should be placed immediately after pulpotomyto eliminate the need for placement of an interimrestoration. An interim restoration is prone to marginalbreakdown, and the weakened tooth to fracture.Complete coverage with a preformed stainless Steelcrown strengthens the weakened crown and protectsagainst leakage at margins of the pulpal space res-toration.

Once the appro pria te-si zed stainless steel crown hasbeen selected, it is important that the margins of thecrown be well adapted to the anatomic form of theprepared tooth. Myers" has shown that rough crownmargins enhance plaque accumulation, frequently

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resulting in gingival inflammation. Although Ion Ni-Chro crown.s (3M Dental Products Div) closely resem-bie the anatomic form of primary molars, propertrimming, contouring, and finishing are essential to en-sure proper fit. Martens and Dermaut'" demonstratedthat the results of trimming crown margins with anahrasive wheel are superior to those achieved withcrown and bridge scissors. Similarly, use of a rubberwheel for polishing results in a smoother crown marginthat is less likely to accommodate plaque aceuniulation,Tripoli and jeweler's rouge, applied by rag wheel on alathe, can be used to attain an especially fine surfacepolish.

References1, Judd PL, Kenny DL: Formocresol concerns: a review, J Can

Dtiif A i w 1987:53:401-405,

2, Myers DR, et al: The acute toxicity of ¡ligh doses of systcm-ically administered formotresol in dogs, Pediatr Dem1981;3:37-41,

3, Beali JR, Ulsamer AG: Formaldehyde and hcpatotoxitity: areview, J Toxicot Environ Health 1984:13:1-21,

4, Rolling I, Thulin H: Allergy tests against formaldehyde, cre-sol, and eugenol in children with pulpotomized primarjteetb, Scand J Dem Res 1976:84:345-347.

.•;, MyersDR. Shoaf HK, DirksenTK, et al: Distribution of 14Cformaldehyde after pulpotomy with formocresol, J Am DentAssoc 1978:96:805-813,

6, Ranly DM: Assessment of the systemic distribution and toxic-ity of formaldehyde following pulpotiimy treatment, 1. J DeniChild 1985;52:431^34,

7, Ranly DM, Hom D: Assessment of the systemic distributionand toxicity of formaldehyde following pulpotomy treatment,[|, / Dem Child 1987;.S4:40-44,

5, Paîhley EL, et al: Systemic distribution of I4C formaldehydefrom formocresol-trcated pulpotomy sites, J Dem Res198O;59:602-607,

9, Myers DR. Pasbley DH, Lake FT, et al: Systemic absorptionof 14C-gluteraldehyde from glutcraldcbyde-trcated pulp-otomy iiteb. Pediatr Deni 1986;8:134-138,

10, Fuks AB, Bimstein E. Guelman M. et al: Assessment of j 2percent buffered gluteraldehyde solution in pulpotomized pri-mary teeth of school children. J Dem Child lW0;57:371-375,

11, Sun HW, Feigal RJ, Messer HH: Cytotoxicity of gluteral-dehyde and formaldehyde in relation to time of exposure andconcentration, Pediair Dem W90; 12:303-307,

12, Via W: Evaluation of deciduous molars treated by pulpotomyand calcium hydroxide, J Am Dent Assoc 1955:50:34—43,

13, Spedding RH, Mitchell DH, McDonald R: Formoeresol andcalcium hydroxide therapy,,/ Dent Res 1965:44:1023-1034,

14, Yacobi R, Kenny DJ, Judd PL, et al: Evolving primary pniptherapy techniques, 7/l;fi Deni Assoc l99];122:83-85,

15, Myers DR: A clinical study of tbe response of the gingival tis-sue surrounding stainless steel crowns, / Deni Child1975:42:281-284,

16, Martens LC, DermauL LR: The marginal polishing of Ion Ni-Chro crowns: a preliminary report. J Dent Child 1983,5(1:417-421,

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