Microleakage of Three Luting Agents Used with Stainless Steel Crowns Joel H

Microleakage of three luting agents used with stainless steel crowns Joel H. Berg, DDS, MS David E. Pettey, DDS Max O. Hutchins, PhD

Abstract al. 1985; Shen and Herrin 1986). Dye penetration studies The microleakage through margins of stainless steel examine the permeability of the margin to a dye, after crowns cemented with polycarboxylate, zinc phosphate, or which an assessment of the linear amount of penetration glass ionomer cement was evaluated by measuring the is made (Crim and Shay 1987; Kanca 1987; Gordon et al. amount of 4SCa leakage through the crown margins through 1986). Radiopermeability studies do not require direct 56 days after cementationin an in vitro environment. There identification of leakage by the investigator in terms of was no cement-specific difference in marginal leakage as penetration, as the measurement is determined by the measuredby this technique. The amountof leakage for each scintillation counting device. The scintillation counting cement stabilized three days after crown placementand re- device quantitatively measures the amount of radioac- mained constant throughout the experimental period. The tivity in a solution which has traversed a margin or data suggest that the newer glass ionomercement provides junction (Herrin and Shen 1985). This latter technique comparableprotection to that of the other two traditional thus appropriate for producing a continuous variable cementsused with stainless steel crowns. subject to parametric statistical interpretation. Little has been done to examine the luting agent-related permea- Glass ionomer cement is the newest introduction to bility of the cemented stainless steel crown using any cements used for placing stainless steel crowns. technique. The adaptation of glass ionomer material to tooth The purpose of this investigation was to determine structure has been shownto be better than the adapta- the amount of microleakage through the margins of tion of other restorative materials (Chan et al. 1985; stainless steel crowns cemented onto primary teeth with McLeanet al. 1985; Norris et al. 1986; Hicks et al. 1986). glass ionomer cement relative to the marginal mi- The close adaptation of glass ionomer to dentin and croleakage of stainless steel crowns cemented with zinc enamel has precipitated the development of formula- phosphate and polycarboxylate cements. tions of glass ionomer for cementing extracoronal restorations. Materials and Methods Yet, it is quality of the tooth preparation for the Twenty primary molars were selected from a supply stainless steel crown in conjunction with the cement of exfoliated or extracted teeth from the Department of (Rector et al. 1985; Savide et al. 1979; Noffsinger et al. Pathology at The University of Texas Dental Branch. 1983) which retain the cemented crown onto primary Teeth were selected that had little or no decay, and teeth. Therefore, the most important properties of using sufficient intact tooth structure so that a good crown a luting agent in the placement of stainless steel crowns marginal seal could be obtained on the basis of a good onto primary teeth are those relating to resistance to clinical examination. Each of the 20 teeth were hand local environmental factors. scaled and cleaned to remove debris and stored in room The amount of microleakage through the stainless temperature tap water. Teeth (specimens) were steel crown margin is of particular concern (Andrewset mounted in a self-curing acrylic base to allow ease in al. 1976; Grieve et al. 1981). Manystudies have exam- handling. Each specimen was weighed and the acrylic ined various cements in terms of microleakage by using was trimmed so that each specimen weighed 4.5 g. dye penetration and radiopermeability techniques (Mondelli and Galan 1987; Myers et al. 1983; Gordon et

Pediatric Dentistry: September,1988 - Volume10, Number3 195 The acrylic was coated with polyurethene to provide Results a sealed surface. Standard stainless steel crown prepara- The radioactivity in tions were made on all teeth. A #6 round bur-size each sample was corrected hemispherical preparation was made at the center of the for background; the count- occlusal surface. A pretrimmed and precrimped stain- ing efficiency was calcu- less steel crown (Ion -- 3MDental Products Division; St lated using the external Paul, MN)was custom fitted for each tooth. Each crown standard method and was was crimped and contoured to allow for the best mar- expressed as disintegra- ginal fit achievable on the basis of a thorough examina- tions per minute. tion with an explorer. The specimens were randomly Disintegrations per. divided into four groups. Each specimen was labeled by minute were corrected to group; i.e., control (no cement), zinc phosphate (Fleck’s express what would have Cement-- Mizzy Inc, Clifton Forge, VA), polycarboxyl- been the original level of ate (Durelon -- Premier Dental Products Co, Norris- activity considering the town, PA), or glass ionomer (Ketac-Cem -- ESPE-Pre- 164-day half life of 4sCa mier Sales Corp, Norristown, PA). The specimens were using the equality: dried thoroughly and a damp cotton pellet (deionized water) was placed in the occlusal recess (Fig 1). Five A= Aoe(-0.693t/T1/2) microliters of a 2.0 where: A= convertedactivity at time of FIG 3. Specimen immersed in ~tCi/~tl solution of sampleA° = original activity of isotope saline. 4sCa was pipetted onto the saturated (2.0~tCi/~tl) cotton pellet of t -- numberof daysafter isotopeproduction T1/2 = half life of 4sCa each specimen. (164days) Each custom Analysis of variance confirmed no significant differ- crown was ce- ence between the leakage of radioisotope through the mented or placed margins of crowns placed without cement and those onto its specific placed with any of the three cements at each of the four specimen (Fig 2). sampling times after crown placement (Fig 4). There Each specimen F~G1. Pellet containing 45Caplaced was no statistical difference in the leakage of radioiso- into occlusal well. then was posi- tope through the margins of crowns cemented with tioned in its own8- glass ionomer cement, zinc phosphate cement, and oz jar containing 70 polycarboxylate cement at any sampling time postce- ml of physiologic saline, and a screw-top lid was placed mentation. Scintillation counts were.statistically lower (Fig 3). The jars were put into a large electric water bath one day postcrown placement that at any subsequent maintained at 37°C and then submerged about two- sampling time through 56 days (P < .05; Fig 4). Radioiso- thirds of their height. tope leakage through the margins of all specimens was One day, 3 days, 7 days, and 8 weeks after placement not detectably different at any sampling time after I day of the crowns, two 50-~tl samples of fluid were pipetted for any of the cements. from each specimen jar and placed into separate scintillation mini-vials. Six ml of scintillation fluid (Ready Discussion Solv TM -- Beck- This study used the stainless steel crown placed or man; Fullerton, cemented onto a primary tooth in a model in vitro CA) was added to environment to examine the differential permeability of each of the 40 vials. various luting agents commonlyused to place stainless The vials were lid- steel crowns in children. The results indicate that there ded, labeled, and is no differential permeability of the three luting agents placed in counting to 4sCa. Additionally, the results showa stabilization of racks in which scin- isotope leakage by day 3, with a maintenance of the tillations per min- levels of leakage though the final 8-week evaluation ute were measured after the initial (1-day) sample was taken. by a liquid scintilla- The results suggest that each of the three tested tion counter (Beck- luting agents provide an equivalent inhibition of perfu- F~G2. Crownplacement. man). sion.of isotope through the margins of the cemented

196 STAINLESS STEEL CROWNCEMENT MICROLEAKAGE: Berget al. _+582 [] NoCement (control) -~- [] ZincPhosphate _+457 [] Polycarboxylate +5_.~37 [] GlassIonomer _~ -~ 5000

+492_]_.

~ 5645 ’ 4965 5f91 .~_ _+257 -+277 3416 -+89 -+154 ~ ~ +136

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I day 3 day 7 day 56 day (N-- 10in all cases) F~c 4. Scintillations/min convertedto disintegrations/min (mean+ SEof the mean)for each cement-specificgroup of specimens at each samplingtime. stainless steel crowns. Although the measured leakage has been shown to be less than that of polycarboxylate of 4sCa through the cement margins does not necessarily or zinc phosphate cements over a 12-month period equate with the clinical leakage of oral environment (Phillips et al. 1987). The film thickness of glass ionomer fluids, it gives a good approximationof the capability of cement has been demonstrated to be acceptable relative the various luting agents to act as a permeability barrier. to other luting cements (Wongand Bryant 1986). These Minimizing permeability to oral fluids near the facts together with the knowledgethat a bond is formed margin of stainless steel crowns is important for preven- between the glass ionomer cement and tooth structure tion of secondary carious attack (Hicks et al. 1986). The suggest that glass ionomer cement, when used as a crowns placed in this study without a luting agent luting agent clinically, will exhibit acceptable mainte- exhibited about 4 times the leakage of isotope through nance of favorable properties. the crown margins at each of the samPling times com- Several investigators have either scientifically or pared with any of the crowns placed with cements. The anecdotally provided information suggesting postce- agent used between the internal aspect of the stainless mentation sensitivity using glass ionomer as a luting steel crown and the tooth acts as a medium by which agent with permanent tooth crowns (Smith and Ruse resistance to permeation is provided (Norris et al. 1986; 1986; American Dental Association Council on Dental Knibbs et al. 1986). When glass ionomer cement has Materials 1984). The present report suggests that in- been used to lute orthodontic bands which were subse- creased permeability to oral fluids can be ruled out as a quently subjected to tensile forces to evoke their re- potential source of cement-specific sensitivity after moval, it was found that the glass ionomer remained cementation of stainless steel crowns placed onto pri- firmly bound to the tooth structure, and the failure mary teeth. occurred at the glass ionomer/band interface (Norris et Fluoride release from the glass ionomer luting agent al. 1986). This phenomenonmight result in the forma- mayprovide beneficial characteristics not inherent to tion of "coping" of glass ionomer cement which could other luting agents. Other reports have shown that resist contact of oral substances and underlying tooth fluoride release from glass ionomer materials is of suf- structure. ficient concentration to alter bacterial growth (Tobias et The in vivo disintegration of glass ionomer cement

Pediatric Dentistry: September,1988 ~ Volume10, Number3 197 al. 1985; Jedrychowski et al. 1983), and to avert carious Hicks MJ, Flaitz CM,Silverstone LM:Secondary caries formation in vitro around glass ionomerrestorations. Quintessence17:527-32, attack at margins of restorations (Hicks et al. 1986). 1986. Although our data suggest that glass ionomer cement does not exhibit less leakage of isotope through the JedrychowskiJR, Caputo AA,Kerper S: Antibacterial and mechani- margin of stainless steel crowns than the other cements, cal properties of restorative materials combined with chlorhexidines. J Oral Rehabil 10:373-81,1983. there may be advantages to its use not inherent to these other luting materials. Kanca J: Posterior resins: microleakage below the cementoenamel junction. QuintessenceInt 18:347-49,1987.

Conclusions Knibbs PJ, Plant CG, Shovelton DS: The performance of a zinc The findings of this study suggest that: (1) there is polycarboxylate luting cement and a glass-ionomer luting ce- apparent differential permeability of glass ionomer, ment in general dental practice. Br Dent J 160:13-15,1986. zinc phosphate, and polycarboxylate cements when McLeanJW, Powis DR, Prosser HJ, Wilson AD: The use of glass used as a luting agent with stainless steel crowns on ionomercements in bondingcomposite resins to dentin. Br Dent primary teeth; and (2) the leakage of radioactive 4sCa J 158:410-14,1985. isotope through the margin of stainless steel crowns Mondelli J, Galan J: Marginal microleakage in cemented complete cemented with any of the above media stabilizes by the crowns. J Prosthet Dent 40:632-36, 1987. third day after cementation, and is maintained at the same level for at least 8 weeks. Myers ML, Staffanou RS, Hembree JH, Wiseman WB:Marginal These findings show that the microleakage of glass leakage of contemporary cementing agents. J Prosthet Dent 50:513-15,1983. ionomer cement is not greater than the microleakage of zinc phosphate or polycarboxylate cements when used Noffsinger DP, JedrychowskiJR, CaputoAA: Effects of polycarbox- to lute stainless steel crowns onto primary molars. ylate and glass ionomercements on stainless steel crownreten- tion. Pediatr Dent 5:68-71, 1983. Dr. Bergis an assistant professor, pediatric dentistry, and Dr. Hutch- ins is a professor and chairman,physiology, The University of Texas Norris DS, McInnes-LedouxP, SchwaningerB, WeinbergR: Reten- Dental Branch;Dr. Pettey is a resident, WestL.A. Veteran’s Admini- tion of orthodontic bands with new fluoride-releasing cements. stration, Los Angeles,California. Reprint requests shouldbe sent to AmJ Orthod 89:206-11, 1986. Dr. Joel H. Berg, Dept. of Pediatric Dentistry, TheUniversity of Texas Phillips RW,Swartz ML, Lund MS, Moore BK, Vickery J: In vivo Dental Branch, Houston, TX77225. disintegration of luting cements. J AmDent Assoc 114:489-92, 1987. AmericanDental Association Council on Dental Materials. Reported sensitivity to glass ionomer luting cements. J AmDent Assoc 109:476,1984. Rector JA, Mitchell RJ, SpeddingRH: The influence of tooth preparation and crown manipulation on the mechanical retention of stainless steel crowns. ASDCJ Dent Child 52:422-27,1985. AndrewsKS, HembreeJH: In vivo evaluation of marginal leakage of four inlay cements.J Prosthet Dent 35:532-7, 1976. Savide NL, CaputoAA, Luke LS: The effect of tooth preparation on ChanDC, Reinhardt JW, Schulein TM:Bond strengths of restorative the retention of stainless steel crowns.ASDC J Dent Child 46:25- materials to dentin. GenDent 33:236-8, 1985. 29, 1979. Shen C, Herrin K: Assessmentof microleakageof restorative mate- CrimAC, Shay JS: Microleakagepattern of a resin-veneered glass rials by a diffusion model. J Oral Rehabil 13:355-63,1986. ionomercavity liner. J Prosthet Dent 58:273-75,1987.

GordonM, Plasschaert AJM,Soelberg KB, BogdanMS: Microleakage Smith DC,Ruse ND:Acidity of glass ionomercements during setting and its relation to pulp sensitivity. J AmDent Assoc112:654-57, of four composite resins over a glass ionomer cement base in 1986. Class V restorations. Quintessence12:817-20, 1985. Tobias RS, BrowneRM, Wilson CA: Antibacterial activity of dental Gordon M, Plasschaert AJM,Stark MM:Microleakage of several tooth-colored restorative materials in cervical cavities. A com- restorative materials. Int EndodJ 18:161-71,1985. parative study in vitro. DentMater 2:228-31, 1986. WongTCC, Bryant RW:Glass ionomer cements: some factors in film thickness. AustDent J 31:81-85, 1986. Grieve AR, Jones JC: Marginal leakage associated with four inlay cementingmaterials. Br DentJ 151:331-34, 1981.

Herrin HK,Shen C: Microleakageof root caries restorations. Gero- dontics 1:156-59, 1985.

198 STAINLESS STEEL CROWNCEMENT MICROLEAKAGE: Berg et al.