Zinc oxide-eugenol pulpotomy and stainless steel crown restorationof a primary molar

Pédiatrie Dentistry

Zinc oxide-eugenol pulpotomy and stainless steel crown restoration of a primary molar Theodore P, Croll* / Constance M. Killian* * The most dtirable and reliable method of retaining a primary molar in the motith after a pulpotomy procedure is complete-coverage restoration with a preformed stainless steel crown. This paper describes a method for performing pitlpotomy and stainless steel crown restoration of a primary molar. Neither formocresol, ghiteraldehyde, nor calcium hydroxide is tised during the pulpotomy phase of the treatment.

(Quintessence Int 1992:23:383-388.)

Introduction

Informal surveys of general dentists reveal that many who treat children seldom use stainless steel crowns for primary molars. Some dentists do not even have preformed stainless steel crown kits in their office supply inventory. When dentists are queried as to why they are reltictant to use stainless steel crowns, the usual response is that the dental school experience in pédiatrie dentistry casts a negative light on such "advanced" concepts as stainless steel crowns. Pédiatrie dentists, especially those in nonQuoridated areas or other regions with a high prevalence of caries, would be severely hampered in treating eotnplex carious le-

sions or malformed or severely traumatized primary canines and molars if preformed stainless steel crowns were not availahle.

While the debate continues over the hest type of intrapulpal space medication for use during pulpotomy procedures for primary teeth, a surprisingly simple method of pulpotomy has received httle attention. However, the method has proved most valuable and reliable in clinical use over the past 20 years.

This paper documents a step-hy-step procedure for restoration of a pulpally involved primary first molar using a thick paste of zinc oxide-eugenol alone as the pulpal space obturation material. The pulpotomy is followed hy immediate placement of a customadapted, preformed stainless steel crown.

Technique

* Private Practice, Pédiatrie Dentistry, Doyiestown, Pennsylvania; Clinica) Associate Professor, Department of Pcdiatric Dentistry, University of Pennsylvania, School of Dental Medieine; Adjunct Professor, Department of Pédiatrie Dentistry, University of Texas, Healtb Science Center at Houston {Dental Branch), ** Private Practice, Pédiatrie Dentistry; Doyiestown, Pennsylvania; Clinical Assistant Professor, Department of Pédiatrie Dentistry, University ol Pennsylvania, School of Dental Medicine, Address all correspondence toDrT, P. Croll, Georgetown Commons.

Suite 2, 708 Shady Retreat Road, Doylestowu, Pennsylvania 18W1,

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

Discussion

Prospective success of a pulpotomy begins during the treatment-planning phase of the procedure. If careful criteria are used to evaluate the tooth for which pulpotomy is planned, the prognosis for long-term success is better.

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Fig 1 Primary first moiar with severe carious destruction.

After appropriate loeai anesthetic is administered, rubber dam is placed.

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

Fig 3 A sterile, water-cooled carbide bur is used to remove caries and enter the pulp cbamber. A sterile, siowspeed round bur dĂŠbrides aii pulpai tissue from the chamber to the level of the root canai openings.

Fig 4 A steriie cotton pellet is compressed into the pulp chamber and retained until residuai hemorrhage of radicular pulpal tissue has ceased.

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

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

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Fig 7 Axial coronal preparation is performed with a watercoded, coarse diamond bur. The wooden wedge protects interproximal gingivai tissue.

Fig 8 After the tooth has been reduced axially, maintaining tooth form in miniature, axio-occlusal line angles are rounded.

Fig 9 The finished preparation is shown from the occlusal view. Note the mesial and distai spacing and the axiai scalloping to increase cement-tooth structure interface.

Fig 10 (mirror view) A crown with oimensions that wiii replicate the original coronai form in aii spatial reiationships is selected. Contacts are reestabiished, and original marginal ridge heights are duplicated.

Fig 11 A spoon excavator or cleoid-discoid is used to remove the crown form after try-in. Note the mesial dĂŠcalcification lesion on the adjacent second molar. That lesion wili be trimmed smooth and the surface treated with topical fluoride solution.

Fig 12 A heatless stone is used to establish correct coronal length. Crown-cutting scissors are much less precise for marginal cutting.

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

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

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

Fig 16 Excess cement is removed with sharp band instruments, such as a sealer or a cleoId-discoid, or an ultrasonic scaier. Excess proximal cement can be dislodged with knotted dental tape.

Fig 17 The finished crown.

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Fig ISa Another primary first molar is shown 7 years afler zinc oxide-eugenoi pulpotomy and piacement of a stainless steel crown.

Fig 18b The pulpotomy and crown are shown radiographicaiiy (left) 4 years after treatment and (right) 7 years postoperative i y.

Contraindications for vital pulpotomy in a primary molar include history of spontaneous pain; sensitivity to perctission; mobility of the tooth: presence of sinus tract, indicating dcntoalveolar abcess; and radiographie evidence of pathosis. Any of these signs or symptoms indicate that the inflammatory process has progressed beyond the confines of the involved tooth into adjacent tissues. Likelihood for a successful pulpotomy in such cases is poor.

During preparation of the tooth, rubber dam is used to isolate the tooth from surrounding soft tissues and saliva. Exposed pulpal tissues are therefore protected from salivary contamination.

Use of formocrewl as a pulpal tissue fixative is controversial.'~' Both in vitro and in vivo studies have demonstrated that form ocre so I placed in contact with vital pulpal tissue is distributed systemically.'"^ Formocresol with '""C-labeled formaldehyde has been used in pulpotomies and subsequently recovered in liver, kidney, heart, spleen, and lung tissue of treated animals.^ GI Uteraldehyde has been studied as an alternative to formocresol for pulpal fixation.''"' However, gluteraldehyde placed in contact with pulpal tissue is also distributed systemicalJy.^ In addition, a clinical sludy of gluteraldehyde pulpotomies did not report a success rate equal to that demonstrated by formocresol.'" Further studies of the effect of concentration and exposure time of gluteraldehyde on pulpal tissue have been recommended to ascertain clinical usefulness of gluteraldehyde."

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

The concept of nonaldehyde pulpal therapy for primary teeth has recently been described. Yacobi et al'* reported a technique for pulpectomy that uses only zinc oxide-eugenol paste.''' At 12 months, their rate of success was the same as that reported for formocresol pulpotomy. Over the past decade, we have performed zinc oxide-eugenoi pulpotomies for primary molars without using any other agent and have had similar chnical results. In light of concerns regarding safety of aldehyde compounds, zinc oxideeugenol pulpotomy should be considered as an alternative to formocresol or gluteraldehyde pulpotomies for treatment of certain primary molars.

A stainless steel crown is Ihe restoration of choice for a tooth that has undergone pulpotomy. Ideally, the crown should be placed immediately after pulpotomy to eliminate the need for placement of an interim restoration. An interim restoration is prone to marginal breakdown, and the weakened tooth to fracture.

Complete coverage with a preformed stainless Steel crown strengthens the weakened crown and protects against leakage at margins of the pulpal space restoration.

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

In an effort to avoid formocresol and gluteral-

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Pédiatrie Dentistry resulting in gingival inflammation. Although Ion NiChro crown.s (3M Dental Products Div) closely resembie the anatomic form of primary molars, proper trimming, contouring, and finishing are essential to ensure proper fit. Martens and Dermaut'" demonstrated that the results of trimming crown margins with an ahrasive wheel are superior to those achieved with crown and bridge scissors. Similarly, use of a rubber wheel for polishing results in a smoother crown margin that is less likely to accommodate plaque aceuniulation, Tripoli and jeweler's rouge, applied by rag wheel on a lathe, can be used to attain an especially fine surface polish.

References 1, 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 systcmically administered formotresol in dogs, Pediatr Dem 1981;3:37-41, 3, Beali JR, Ulsamer AG: Formaldehyde and hcpatotoxitity: a review, J Toxicot Environ Health 1984:13:1-21, 4, Rolling I, Thulin H: Allergy tests against formaldehyde, cresol, and eugenol in children with pulpotomized primarj teetb, Scand J Dem Res 1976:84:345-347. .•;, MyersDR. Shoaf HK, DirksenTK, et al: Distribution of 14C formaldehyde after pulpotomy with formocresol, J Am Dent Assoc 1978:96:805-813, 6, Ranly DM: Assessment of the systemic distribution and toxicity of formaldehyde following pulpotiimy treatment, 1. J Deni Child 1985;52:431^34, 7, Ranly DM, Hom D: Assessment of the systemic distribution and toxicity of formaldehyde following pulpotomy treatment, [|, / Dem Child 1987;.S4:40-44, 5, Paîhley EL, et al: Systemic distribution of I4C formaldehyde from formocresol-trcated pulpotomy sites, J Dem Res 198O;59:602-607, 9, Myers DR. Pasbley DH, Lake FT, et al: Systemic absorption of 14C-gluteraldehyde from glutcraldcbyde-trcated pulpotomy iiteb. Pediatr Deni 1986;8:134-138, 10, Fuks AB, Bimstein E. Guelman M. et al: Assessment of j 2 percent buffered gluteraldehyde solution in pulpotomized primary teeth of school children. J Dem Child lW0;57:371-375, 11, Sun HW, Feigal RJ, Messer HH: Cytotoxicity of gluteraldehyde and formaldehyde in relation to time of exposure and concentration, Pediair Dem W90; 12:303-307, 12, Via W: Evaluation of deciduous molars treated by pulpotomy and calcium hydroxide, J Am Dent Assoc 1955:50:34—43, 13, Spedding RH, Mitchell DH, McDonald R: Formoeresol and calcium hydroxide therapy,,/ Dent Res 1965:44:1023-1034, 14, Yacobi R, Kenny DJ, Judd PL, et al: Evolving primary pnip therapy techniques, 7/l;fi Deni Assoc l99];122:83-85, 15, Myers DR: A clinical study of tbe response of the gingival tissue surrounding stainless steel crowns, / Deni Child 1975:42:281-284, 16, Martens LC, DermauL LR: The marginal polishing of Ion NiChro crowns: a preliminary report. J Dent Child 1983,5(1:417-421,

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