Dental Research

Retentive strength of six temporary dental cementsPaul S. Olin* / Joel D. Rudney** / Elaine M. E. Hill***

The retentive strength of three zinc oxide-eugenol cements and three noneugenol-con-taining zine oxide cements and the effect of the addition of petrolatum on retentionwere tested. The addition of petrolatum was found to affect retention of the cementssignificantly. Retention strengths varied from 1.6 kg to 40.0 kg. Of the Class 1.Type 2. systems tested, noneugenol cements had higher retentive values than did theeugenol-containing cements. (Quintesseitee Int 1990;21:197-200.)

Introduction

Provisional cementation of permanent and provision-al restorations is praetieed widely for a variety of clin-ical reasons, including the desire to make further oc-clusal adjustments, continuation of periodontal ther-apy, atid irtspection of abutment teeth for support.'Additionally, the patient's speech, ability to maintainoral hygiene, and satisfaction with the esthetic ap-pearance of the restoration can be evaluated while theability to make further adjustments is retained. Lisp-ing, cheek biting, and shade problems can all be cor-rected prior to flnal cementation. Chnicians may wishto cement a restoration temporarily for a period ofweeks or months or for as long as a year. A temporarycement, therefore, must possess a balance of two ma-jor qualities: It must be strong enough to hold therestoration in place and seal all retainers against leak-age, but it must not be so strong that the restorationcannot be removed easily and without darnage whenthe clinician so desires.- The luting strength of tem-porary cements can vary widely, and, in choosing aeement, clitiicians must also consider variables such

Assistant Professor. Division of Fised Prosthodontics, 5-450Malcolm Moas Health Sciences Tower, University of Minne-sota. School of Dentistr>'. 515 Delaware Street SE, Minneap-olis, Minnesota 55455.Assistant Professor. Division of Oral Biology, 17-226 MalcolmMoos Health Sciences Tower, University of Minnesota.Principal Laboratory Technician, Dental Research Institute,18-104 Malcolm Moos Health Sciences Tower. University ofMinnesota.

as the type and location of the restoration, length ofspan, number of units, retentive qualities of the re-tainers, and the amount of occlusal stress to whichthe restoration will he subjected.'

Two major types of temporary cements are avail-able: zinc oxide and zinc oxide-eugenol. The Ameri-can Dental Association'* cla.ssifies zinc oxide-eugenolcements according to types and classes. Type 1 ce-ments are for temporary cementation, Class 1 mate-rials are powder and liquid. Class 2 are two paste sys-tems. Class 3 are nonsetting. The ADA"' reeomtnendsa setting time of 4 to 10 minutes at 37 ± 1 "C and amaximal compressive strength at 24 hours of 356 kg/em-.

Zinc oxide-eugenol cements possess good seahngcapability and antibacterial action.'̂ Eugenol. how-ever, is a potential allergen, so zinc oxide cements with-out eugenol must be substituted in patients who aresensitive to eugenol. Clinicians must also be cautiouswhen ustng eugenol-contaming cements to seat pro-visional restorations fabricated in acrylic resin. Dis-coloration of acrylic resin has been observed after 3days of exposure to eugenol vapor.''

Oldham et al' tested the retentive properties of avariety of dental cements, among them two zinc ox-ide-eugenol temporary cements. The retention of uni-formly prepared inlays was tested following 24 hoursof storage in water, and the tensile strength requiredto remove the restorations was compared to baselinedata gathered for restorations cemented with zincphosphate eement. Oldham et al' found thai appre-ciably higher tensile loads were required Lo unseat res-torations cemented with zinc phosphate than thosecemented with zinc oxide-eugenol. Neither the study

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Dental Research

Fig 1 Metal casting waxed, cast, and fit on standardizedmetal dies with 6 degrees of taper.

Fig 2 Crown loaded on testing machine.

by Oldham nor the current sttidy found an unequi-vocal relationship between compressive strength andretentive properties, suggesting that other factors,such as film thickness, are important.

Despite the findings reported by Oldham et al', re-tention and compressive strength are generally ac-cepted as related. The compressive strength of com-monly used temporary cements ranges from 28 kg/cm'to 140 kg/cm-." For short-term cementation of per-manent crown and bridge restorations, a cement witha low compressive strength is recommended.* It is alsogenerally recognized ihat addition of petrolatum tothe temporary cement reduces retention. However, thequantitative retentive strengths of temporary cementshave not been previously reported.

This study reports on the retentive strengths of threezinc oxide-eugenol and three noneugenol-containingzinc oxide cements commonly used for temporary ce-mentation and evaluates the effect that the additionof petrolatum has on retentive strength.

Method and materials

Twenty base metal castings were waxed, cast, and fiton standardized metal dies with 6 degrees of taper(Fig I). Six cements were selected for evaluation; No-

genol (Coe Laboratories, Inc). Ereegenol (G-C Inter-national), and Z.O.N.E. (Cadco Dental Products) areall noneugenol-containing cements, and Tempbond(Kerr/Sybron Corp). Flow Temp (Premier DentalProducts), and ZOE B & T (LD Caulk Co) are eu-genol-containing cements. Cements were mixed ac-cording to their respective manufacturer's instruc-tions. To evaluate the effect of petrolatum on the re-tention of cemented crowns, one eugenol (Tempbond)and one noneugenol (Nogenol) cement was mixedwith equal proportions ofaccelcrator and petrolatum.Retentive strength was compared using a repeated-measures design in which each crown was tested withevery cement. Crowns were uniformly lined with ce-ment and placed in a fixture providing 4.5 kg of seat-ing load. Casting seating is critical to retention, there-fore a uniform 4.5-kg loading and symmetrical pre-cision dies were used to facilitate reseating. After 10minutes, the cemented crowns were placed in water.and stored at 37 ̂ C for 24 hours. Following storage,the crowns were loaded on a 4200 series Instron uni-versal testing machine (Instron Corp) with a crossheadspeed of 1.0 mm/min, and the relative retentivestrength of the cement was measured (Eig 2). Eachcrown was cemented with each of the six temporarycements. Following meticulous, ultrasonic cleaningwith a temporary cement remover (DriClave VK-6,

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Dental Research

40-

» 30"

> 20-

10-

0-

"Tempbo

Z.O.N.E

5.6

1,6 ^ H I

TB/p No/p

d/petrolalum

BST

7.2

HFLO

Nog

15.3

8.8 ^ 1• •TB FRE

cements

snol/petro

19.9•1•ZON

5tum

24,3

11•NO

Flow

39.9

• values

•-••1BST

Temp Freegenol

Fig 3 Retentive strengths ot the tested temporary ce-ments.

1.5-

og k

g

0.5-

ooJ

i T

II0

1 59 t i l

Ilii1 ^ 1 ^ 1 ^ 1 .25

••hwmTB FLO B&T ZONI ZONS FRE TB/p

cemenls•Tempbond/pelrolatu

Z,O,N,E. B8T

n Nogenol/petfolatum

.to

i11•NO

Flow

38

TiNG/p

Teme

• values

Freegenol

Fig 4 Base 10 logarithmic retentive strengths of the ce-ments.

Table i Pairwise differences between treatments, as found by Tukey's test

Flowtemp NSZOE B&T P< ,05 P< ,05Z.O.N.E.2 NS NS P< ,05Freegenoi NS P< ,05 P< .05 NSTempbond/p* P< .05 P< .05 P< .05 P< .05 P<-05Nogenol P < ,05 P< .05 NS P<-05 NS P< .05Nogenol/p* P< ,05 P< ,05 P< ,05 P< .05 P< .05 P< .05 P< ,05

Tempbond Fiowtemp ZOFB&T Z.O,N.F, Freegenol Tempbond/p* Nogenol

' Equal lengths petrolatum,NS = not sicnificaiit.

Columbus Dental), each casting was visually inspectedto assure proper reseating of the casting on the re-spective test die. The cementing step was then repeatedas needed. The significance of differences between ce-ments was tested using one-way repeated-measuresanalysis of variance. Differences between individualpairs of cements were evaluated by means of Tukey'sa posteriori test.'

Results

Measured retentive strengths are presented in Fig3-Evaiuation of initial results showed that distributionsof retentive strengths for some cements were non-nor-

mal. This had a substantial effect on the outcome ofthe statistical analysis. To correct this problem, scoreswere reexpressed as base ten logarithms,' Results forlog retentive strengths are presented in Fig 4. Meanretention values for the six cements ranged from a lowof 1.6 for Tempbond with petrolatum to a higb of 39,9for ZOE B & T, Standard deviations varied from a lowofO,10 for Nogenol and ZOE B&T toahigh of 0.59for Z,O,N,H,, which was tested twice because of aninitially high standard deviation. Overall differencesbetween eetnents were highly significant at /" < ,05,Pairwise différences between treatments by Tukey'stest are presented in Table 1, While ZOE B&T hadthe highest retentive strength, it was not significantly

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Dental Research

different from Nogenol because Tiikey's test is a con-servative analysis.' Freegenol and Nogenol did not dit~-fer significantly from each other in retention, and nei-ther did Tempbond and Flowtemp (Table 1), makingthese pairs of cements interehangeable in lerms oftheir retention. Petrolatum was added to Tempbondand Nogenol in equal lengths of hase and catalyst,approximating one third the volume of the total mix.The addition of petrolatum significantly reduced re-tention rates of the cements.

Discussion

The temporary cements investigated in this studyshowed a wide range of ability to retain castings undertest conditions. While it is difficult to predict clinicalperformance based solely on in vitro tests, the highdegree of variability in the retentive strengths of thesecements provides useful information when the seiec-tion of a temporary cement is necessary.

Five of the cements tested were two-paste systems.ZOE B & T is a powder/liquid system and showed thehighest retentive strength. Of the Class 1, Type 2 sys-tems tested, the noneugenol cements had higher re-tention values than the eugenol-containing cements,indieatmg that noneugenol cements could be used notonly in eugenol-sensitive patients, but also wheneverthe need for a higher retentive value exists.

Z.O.N.E. was tested twice because the standard de-viation of the test values was much higher than thatfor the other products (different tubes of the productwere selected for the second trial). On the additionalseries of tests, however, the standard deviation re-

mained high. Retentive strength forfrom 1.2 to 54,8 kg.

ranged

Summary

In attempting to select a temporary cemciii, cliniciansshould consider patient sensitivity to eugenol, the dan-ger that eugenol may discolor acrylie resin restora-tions, desired retention, and the need for predictableclinical performance. If the restoration itself is inher-ently retentive, petrolatum can be added to reduceretention.

References

1. Ewing. JE: Temporary cementation in fixed partiai prostheseiJ Prosthet Dem 1955;5:388-391.

2. Gilson TD. Myers GE: Clinical studies of dental cements. III.Seven zinc oside-eugenol cements used for temporarily cement-ing completed restorations. J Dem Res t970;49:14-20.

J. Smith DC. Dental cements: current status and future prospects.Deni Clin North Am t983;6:763-792.

4. American Dental Association Council on Dental Materials: NewAmerican Dental Association specitlcation No. 30 for dental zinccside-cngenot type restorative materials. J Am Dent As.wct977;95:99l-995.

5. Pasbley EL, Tao L, Pashley DH: The sealing properties of tem.porary filling materials. J Prosttm Dem 1988;60:292-297.

6. Nishi K, Katayama T, Motono H. et al: Discoloration of com-posite resin affected by eugenol vapor during storage. Josai SliilmDaigaku Kiyo 1986; 15:336-340.

7. Oidham DF, Swartz ML. Phillips RW: Retentive properties ofdental cements. / Prosthe! Dent 1964; 14:760-768.

8. Cements. Den! Advisor t985;2:t-8.

9. Sokai RR, Rohk FJ: Biometry, ed 2. San Francisco, WH Free-man. iy8i D

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