In vivo inlay
James 1. Andrews,
D.D.S.,* and John H. Hembree,
The University of Tennessee Center for the Health Sciences, College of Dentistry, Memphis, Tenn.
ast restorations, such as crowns, inlays, and fixed partial denture retainers, have only a reasonably close adaptation to the walls of the cavity preparation. Therefore, a luting medium is used to seal the margins of the restorations. For almost a century, zinc phosphate cement has been successfully used as a dental cementing medium.l The major problem with the zinc phosphate cements is their irritating effect on the dental pul~.~* 3 Although zinc oxide/eugenol cements, designed to be used as luting media, have enjoyed limited success, they are regarded as having inadequate strength to permanently secure a fixed prosthesis. 4*5 More recently, zinc oxide/eugenol cements have been modified by the addition of polymers, ethoxybenzoic acid, and alumina to increase the strengths of these cements.6 An ethyl cyanoacrylate cement that is presently available is designed to repair, stain, and cement restorations. The manufacturer also states that the material can be used as a fissure sealant as well as a restorative material in the acidetch or pin techniques. The question remains as to the pulpal response that this material may elicit. The carboxylate cement system is based upon a modified zinc oxide and an aqueous solution of polyacrylic acid. Although the compressive strength of the carboxylate cements is not as high as that of the zinc phosphate cement, they will adhere to enamel and dentin.7 Investigators have shown that there is little or no pulpal reaction with the carboxylate cements89 0 The purpose of this study is to evaluate in vivo the marginal leakage of zinc phosphate, modified zinc oxide/eugenol, ethyl cyanoacrylate, and carboxylate cements. The isotope Ca,, was used to assay the relative adaptation of the restorative materials.
by L. G. Noel Memorial
Department of Operative Dentistry. Professor, Department of Biomaterials.
Grant No. 2434704607-R74.
Volume 35 Number 5
MATERlALS AND METHODS Six young adult dogs with fully erupted permanent teeth were selected as experimental animals. Each dog was anesthetized for the operative procedures with intravenous pentobarbital sodium at 1 C.C. per 5 pounds of body weight. Following scaling, Class V inlay preparations were prepared on the maxillary and mandibular canines and fourth premolars of each dog using a tapering fissure bur, high-speed instrumentation, and a water spray, Each inlay pattern was waxed directly, invested, and cast using conventional casting procedures. A-type II casting gold* was used to cast each inlay. The inlays were cemented with one of four different cements and finished using conventional finishing methods. The cements used in the study included: an improved zinc phosphate cementt; alumina EBA crown and bridge cement,$ a reinforced zinc oxide/eugenol cement; Cyanodent,$ a carboxylate cement. The marginal an ethyl cyanoacrylate cement; and Durelon,ll leakage of each cement was tested at 72 hours, 3 months, and 6 months by killing two dogs at each time interval; the dogs were given an overdose of pentobarbital sodium. Each tooth was removed by sectioning the coronal portion of the tooth at the height of the gingival crest with high-speed instrumentation. This procedure produced four specimens of each cement at each time interval, or a total of 48 teeth in the study. The procedure used to determine marginal leakage is one that has been previousadaptation of each specimen ly described by Swartz and Phillips. lo The marginal was determined by the presence of the isotope at the interface of the tooth and the restorative material as shown on an autoradiograph. Each specimen was immersed of isotope employed was for 2 hours in Cads isotope solution. The concentration 0.1 mc. per milliliter of solution in the form of calcium chloride with the pH adjusted to 7.0. Prior to immersing the teeth in the isotope solution, the cut end of the tooth was carefully sealed with a combination of nail polish and tinfoil. Upon removal from the isotope, the tooth was washed and sectioned longitudinally through the inlay. The sectioned surface of the tooth was placed on an ultra high-speed periapical dental x-ray film for a period of 17 hours to produce the autoradiograph. The films were developed by use of an automatic system.
RESULTS Marginal leakage at the interface of the tooth and the restorative material was evaluated by the use of the following scale: 0, no evidence of the isotope at the interface of the tooth and the restorative material on the autoradiograph; I, any evidence of the isotope penetrating the interface of the tooth and the restorative material at the cavosurface angle; II, evidence of the isotope at the interface of *J. F. Jelenko and Company, @. S. White Company, $Opotow
Inc., New Rochelle,
Div. of Pennwalt
Mfg. Corp., Brooklyn,
Corp., Philadelphia, N. Y.
$Ellman Dental Mfg. Company, Inc., Cedarhurst, /IPremier Dental Products Company, Philadelphia,
N. Y. Pa.
J. Prosthet. Dent. May, 1976
Fig. 1. Cyanoacrylate cement-72 hours. The arrow points to the restoration; the black line indicates penetration of the isotope. Fig. 2. Cyanoacrylate cement-3 months. The arrow points to the restoration; the black line indicates penetration of the isotope. Fig. 3. Cyanoacrylate cement-6 months. The arrow points to the restoration; the black line indicates penetration of the isotope.
Table I. Marginal
leakage of four inlay luting
Cyanoacrylate Reinforced zinc oxide/eugenol (EBA) Polycarboxylate Zinc phosphate
Cyanoacrylate Reinforced zinc oxide/eugenol (EBA) Polycarboxylate Zinc phosphate Cyanoacrylate Reinforced zinc oxide/eugenol (EBA) Polycarboxylate Zinc phosphate
Degree (No. of specimens). II I 2 2 2
1 2 2
1 2 2
1 3 3
1 2 1
III 4 1 1 4 2 4 2 -
the tooth and the restorative material along the gingival and incisal or occlusal walls, but not penetrating to the axial wall of the preparation; and III, evidence of penetration of the isotope to the axial wall. Autoradiographs were prepared from each tooth in the study. One inlay was lost; therefore 47 autoradiographs were produced. These represented four autoradiographs for each luting medium at each time interval except for one EBA specimen at 6 months. Table I presents the results. All autoradiographs of inlays cemented with the cyanoacxylate cement showed penetration of the isotope to the axial walls of the preparations at all time intervals (Figs. 1 to 3).
.Fig. 4. EBA cement-72 Fig. 5. EBA cement-3 Fig. 6. EBA cement-6
Fig. 1. Polycarboxylate Fig. 8. Polycarboxylate Fig. 9. Polycarboxylate
Fig. 10. Zinc phosphate
hours. months. months.
Fig. 11. Zinc phosphate cement-3 Fig. 12. Zinc phosphate cement-6
hours. months. months.
Andrews and Hembree
J. Prosthet. Dent. May. 1976
Five of the teeth in which inlays were cemented with EBA showed penetration of the isotope to the axial walls of the preparations, and three teeth showed penetration of the isotope along the gingival and occlusal or incisal walls of the preparations. Penetration of the isotope at only the cavosurface angle was seen in three inlays cemented with EBA (Figs. 4 to 6). Six of the inlays cemented with polycarboxylate cement showed penetration of the isotope at only the cavosurface angle. The other six inlays showed leakage along the gingival and incisal or occlusal walls, but the isotope did not penetrate to the axial walls of the preparations (Figs. 7 to 9). One inlay cemented with zinc phosphate cement showed penetration of the isotope to the axial walls of the preparation. Penetration of the isotope along the gingival and incisal or occlusal walls was observed in four of the inlays cemented with zinc phosphate cement, and penetration of the isotope at the cavosurface angle was seen in seven of the inlays (Figs. 10 to 12). CONCLUSIONS
Marginal leakage was demonstrated in all the inlays at all time intervals with all cements by the use of the isotope Ca,,. Gross marginal leakage was observed in all inlays luted with the cyanoacrylate cement at all time intervals. The setting time of this cement is very short, making it difficult to completely seat the inlay before the cement sets. The results of this study indicate that the cyanoacrylate cement is not a satisfactory luting medium for Class V inlays. Inlays cemented with EBA demonstrated leakage patterns similar to those of inlays seated with polycarboxylate and zinc phosphate cements in the specimens taken at 72 hours. In the 3 month and 6 month specimens, greater marginal leakage was seen with EBA cement than with polycarboxylate and zinc phosphate cements. Leakage patterns associated with polycarboxylate and zinc phosphate cements were very similar at all time intervals. The polycarboxylate and zinc phosphate cements showed less marginal leakage than the other two cements at 3 months and 6 months. The results of this study indicate that inlays cemented with polycarboxylate cement and zinc phosphate cement exhibit significantly less marginal leakage than the cyanoacrylate cement and EBA cement over a 6 month period of time. References 1. Guide to Dental Materials and Devices, ed. 7, Chicago, 1974-1975, American Dental Association, p. 49. 2. Manley, E. B.: A Preliminary Investigation Into the Reaction of the Pulp to Various Filling Materials, Br. Dent. J. 60: 321-331, 1936. 3. Silberkweit, M., Massler, M., &hour, I., and Weinmann, J. P.: Effect of Filling Materials on the Pulp of the Rat Incisor, J. Dent. Res. 34: 854-869, 1955. Properties of Some Zinc Oxide Eugenol 4. Anderson, J. R., and Myers, G. E.: Physical Cements, J. PROSTHET. DENT. 45: 379-387, 1966. 5. Swartz, M. L., Phillips, R. W., Norman, R. D., and Oldham, D. F.: Strength, Hardness, and Abrasion Characteristics of Dental Cements, J. Am. Dent. Assoc. 67: 367-374, 1963.
Volume 35 Number 5
Dental Materials, ed. 4, St. Louis, 1971, 6. Peyton, F. A., and Craig, R. G.: Restorative The C. V. Mosby Company, p. 412. of a Carboxylate Adhesive 7. Phillips, R. W., Swartz, M. L., and Rhodes, B.: An Evaiuation Cement, J. Am. Dent. Assoc. 81: 1353-1359, 1970. 8. Smith, D. C.: A New Dental Cement, Br. Dent. J. 123: 54.0-541, 1967. 9. Truelove, E. L., Mitchell, D. F., and Phillips, R. W.: Biologic Evaluation of a Carboxylate Cement, J. Dent. Res. 50: 166, 1971. 10. Swartz, M. L., and Phillips, R. W.: In Vitro Studies on the Marginal Leakage of Restorative Materials, J. Am. Dent. Assoc. 62: 141-151, 1961. UNIVERSITY OF TENNESSEE COLLEGE OF DENTISTRY 847 MONROE AVE. MEMPHIS, TENN. 38163
TO APPEAR IN FUTURE
Sumiya Hobo, D.D.S., Whitsett, D.D.S.
dentistry T. Shillingburg,
of gold-palladium-silver restorations
Eugene F. Huget,
A histologic comparison complete dentures
R. M. Jani, B.D.S., M.D.%,
and K. Bhargava,
, and Howard
E. Cosner, Jr.
B.Sc., B.D.S., M.S.
M.Sc., and Jafar Dadmanesh,
and the associated
M. Jones, D.D.S.,
A study casts David
S. Javid, D.D.S.,
and Jack I. Nicholls,