Microleakage of Five Temporary Endodontic Restorative MateriaIs Mary K. Hagemeier, D.D.S.” Robert L. Cooley, D.M.D., M.S.+
Jeffe?yL. Hicks, D.D.S.’
This study evaluated the ability of five interim endodontic restorative materials to resist microleakage. Sixty extracted human molars were prepared for initial endodontic therapy via occlusal access preparations. After removal of the pulpal tissue, a cotton pellet was placed in the pulp chamber. The access preparations were sealed with one of the following materials or combinations: TERM, Cavit, IRM, Ketac-Silver, or a IRM-Cavit “sandwich” restoration. The specimens were thermocycled for 24 hours (800 cycles), immersed in methylene blue dye for 4 hours, sectioned, and evaluated under a microscope for microleakage. TERM, Cavit, and the IRM-Cavit “sandwich” had virtually no microleakage, while Ketac-Silver and IRM exhibited gross microleakage.
B
nent visible light-curable resin that contains urethane dimethacrylate, radiopaque filler, pigments, and initiators. Ketac-Silver is a glass ionomer with silver fused to the surface of the glass particles by a sintering process and is known as a cermet cement. The purpose of this in vitro study was to compare the ability of these materials to resist microleakage when used in endodontic access preparations.
leaching of endodontically treated teeth can greatly improve the esthetics of teeth that have become discolored.’ One method of accomplishing this treatment is the use of a “walking bleach” or internal bleaching agent. This requires sealing a paste of 30 percent hydrogen peroxide (Superoxol) and sodium perborate in the pulp chamber.* As these materials can be damaging to oral tissues, it is important to have a temporary restoration that provides an effective seal against microleakage. Also, ingress of oral fluids via microleakage may complicate successful bleaching making acceptable esthetics difficult to achieve.3-4 Temporary restorative materials are also used in endodontics to seal access preparations between appointments and prior to placement of a permanent restoration on completion of endodontic therapy. These interim restorations are placed to prevent contamination of the root canal system by oral fluids and microorganisms and to prevent leakage of intracanal medications into the oral cavity. Several materials have traditionally been used for this purpose, such as Cavit and IRM. Several newer materials are now available and are being utilized as well. TERM is one such material and is a one-compo-
METHOD Sixty extracted human molar teeth that had been stored in 10 percent buffered formalin were used in this investigation. Occlusal endodontic access preparations were performed on each tooth with a No. 4 round bur and % DT diamond bur using a high-speed handpiece and water coolant spray. The remaining coronal pulp tissue was removed with a spoon excavator, and the chamber was irrigated with saline and then dried with suction and cotton pellets. To simulate clinical conditions, the chamber floor was covered with a dry cotton pellet prior to placement of the restorative material. The teeth were randomly distributed into five groups of 12 teeth each. In the first group, Cavit (ESPE-Premier, Norristown, PA) was placed according to the manufacturer’s instructions and allowed to set. The second group was similarly treated with IRM (CaulWDentsply, Milford,DE). In the third group, the samples received a base of IRM, which was covered with approximately 3 mm of Cavit to form the “sandwich” restoration. The fourth group received the KetacSilver restorations after the enamel margins were
* S dDentist, USAF Hospital Bergsuorn, Bergstrom AFB, Texas ‘Associate Professor, Department of General Practice w i o r , Advanced Education in General Dentistry Program, University of Tau Health Science Center at San Antonio, San Antonio, Texas Address reprint requests to Dr. Robert L Cooley, General PracticeUrHSCSA, 7703 Floyd Curl Drive, San Antonio, TX 78284-7914 O 1990 B. C. Decker Inc.
166
Microleakage of Restorative Marerials
etched for 60 seconds with 37 percent orthophosphoric acid, rinsed for 30 seconds with an aidwater syringe, and treated with an unfilled bonding agent (Scotchbond 2, 3M Dental Products, St. Paul, MN). The bonding agent was polymerized for 40 seconds with an Optilux 400 unit (Demetron Research Corp, Danbury, CT). In the fifth group, TERM (CaulWDentsply) was placed according to the manufacturer’s instructions and light polymerized for 40 seconds with an Optilux 400 units. All samples were thermocycled in distilled water for 24 hours (800 cycles) at 6”C-60°C with a dwell time of 30 seconds. The roots were sealed with sticky wax and then the entire tooth coated with nail polish except for the restoration and l m m surrounding the restoration. The crowns of the teeth were immersed in S percent methylene blue for 4 hours, rinsed with tap water, and sectioned buccolingually through the restoration with a diamond saw (Isomet, Buehler Ltd, Evanston, IL). After sectioning, the cut surfaces were painted with clear nail polish to prevent dehydration. Three evaluators, blind to the identity of the groups, independently scored the degree of microleakage along the toothlrestoration interface using the following criteria (Fig. 1): 1-dye penetration from the occlusal surface up to one-half the distance to the pulpal floor, 2-dye penetration greater than one-half the distance to the pulpal floor, and +dye penetration extending horizontally along the pulpal floor. Each half of the sectioned specimen was rated, and the one with the greatest degree of dye penetration was recorded. The highest score from the three evaluators was used for statistical analysis.
Table 1. Microleakage Scores Scores for Each Moterial Material
0
Cavit IRM IRM-Cavit Ketac-Silver TERM
10
1
2
3 10
1
9
10
8
1
1
RESULTS The microleakage scores for each material are shown in Table 1. The rating indicating the most severe degree of microleakage from any of the three evaluators was used. Across all evaluations and materials, the three evaluators only disagreed three times and that was by 1 unit of scoring. Cavit exhibited no microleakage in any of the specimens, while the IRM-Cavit “sandwich” had only one specimen with a rating of “2,” and TERM had one specimen with a rating of 1” and one with a “2.” All of the IRM and Ketac-Silver specimens received a “3” score, which was the most severe degree of microleakage (Figs. 2-6). When the data was subjected to statistical analysis (Mann-Whitney U), IRM and Ketac-Silver had significantly more leakage than the other three materials (p < 0.01). The microleakage results obtained from TERM, Cavit, and the IRM-Cavit “sandwich” were not significantly different. “
DISCUSSION The need for a temporary endodontic filling material that resists microleakage of oral fluids is obvious.
Figure 2. Cavit specimen showing penetration of the dye into the material but no microleakage along the tooth-restoration interface.
Figure 1. Scoring criteria used by the evaluators. 167
JOURNAL OF ESTHETIC DENTISTRYNOLUME 2, NUMBER 6 Noc,ember/Derember 1990
Figure 5. Ketac-Silver restoration with dye leakage completely around the restoration and into the pulp chamber.
Figure 3. IRM-Cavit “sandwich” specimen also showing penetration of the dye into the material.
Ludlow7 evaluated microleakage with silver nitrate using Cavit, Cavit-G, and TERM. TERM demonstrated significantly less leakage after thermocycling. Pashley et al* showed leakage with IRM and ZOE after thermocycling using various powdertliquid ratios, though thinner mixes fared somewhat better. Since the start of this study, three similar investigations, which add to the conflicting results cited above, have been published on microleakage of temporary endodontic restorations. In a fuschin dye microleakage study, Jones et aP found Ketac-Silver allowed virtually no leakage, whereas IRM and TERM showed leakage ranging from minimal to extensive after thermocycling. Barkhordar and Stark10 demonstrated excellent sealing with Cavit and TERM, but poor sealing with IRM after thermocycling. Bobotis et all1 evaluated seven materials for microleakage with an apparatus that placed fluid under pressure within the pulp chamber and created the
Figure 4. IRM specimen demonstrating microleakage of the dye complerely around the restoration and into the pulp chamber.
This study found that TERhP, Cavit, and the IRM-Cavit “sandwich” to be superior in resisting microleakage. However, there have been a number of other in vitro studies that have evaluated microleakage in currently available products. Friedman et a l 5 evaluated microleakage of radiosodium from within the pulp chambers sealed with IRM, 20% Cavit-G, and Cavidentin and found that zincoxide eugenol products showed less microleakage than the others. Anderson et al6 demonstrated excellent s a g with TERM and CaVit and significant l e d w e with IRM after 7 days of thermal stress. Hermsen and
Figure 6. TERM restoration with only slight leakage at the occlusd margin. 168
Microleakage of Restorative Materials
potential for microleakage out of the tooth. After 8 weeks Cavit, TERM, and Fuji I1 demonstrated virtually leakproof seals while IRM and polycarboxylate cement showed the greatest leakage.
CONCLUSIONS Five materials were evaluated for microleakage when used as temporary endodontic restorations. TERM, Cavit, and the IRM-Cavit “sandwich” had virtually no leakage and significantly less than IRM or Ketac-Silver.
REFERENCES Howell RA. Bleaching discoloured root-filled teeth. Br Dent J 1980;148:159-162. Nutting E, Poe G. Chemical bleaching of discolored endodontically treated teeth. Dent Clin North Am 1967;1 1:65 5-662. Brown G. Factors influencing successful bleaching of the discolored root-filled tooth. Oral Surg Oral Med Oral Pathol 1965;20:238-244.
4. Nutting E, Poe G. A new combination for bleaching teeth. J S Calif Dent Assoc I963;31:289-334. 5. Friedman S, Shani J, Stabholz A, Kaplawi J. Comparative sealing ability of temporary filling materials evaluated by leakage of radiosodium. Int Endodont J 1986;19:187193. 6. Anderson R, Powell B, Pashley D. Microleakage of three temporary endodontic restorations. J Endodont 1988;14: 497-501. 7 . Hermsen K, Ludlow M. An in-vitro investigation comparing the marginal leakage of Cavit, Cavit-G, and TERM. Gen Dent 1989;37:214-217. 8. Pashley E, Tao L, Pashley D. T h e sealing properties of temporary filling materials. J Prosthet Dent I988;60: 292-291. 9. Jones K, Fruithandler R, Berg J. Microleakage of interim endodontic filling materials. Am J Dent 1990;3:? 1-74. 10. Barkhordar R, Stark M. Sealing ability of intermediate restorations and cavity design used in endodontics. Oral Surg Oral Med Oral Pathol 1990;69:97-101. 11. Bobotis H, Anderson R, Pashley D, Pantera E. A microleakage study of temporary restorative materials used in endodontics. J Endodont 1989;15:569-572.
Jeffe?yL. Hicks, D.D.S.’
This study evaluated the ability of five interim endodontic restorative materials to resist microleakage. Sixty extracted human molars were prepared for initial endodontic therapy via occlusal access preparations. After removal of the pulpal tissue, a cotton pellet was placed in the pulp chamber. The access preparations were sealed with one of the following materials or combinations: TERM, Cavit, IRM, Ketac-Silver, or a IRM-Cavit “sandwich” restoration. The specimens were thermocycled for 24 hours (800 cycles), immersed in methylene blue dye for 4 hours, sectioned, and evaluated under a microscope for microleakage. TERM, Cavit, and the IRM-Cavit “sandwich” had virtually no microleakage, while Ketac-Silver and IRM exhibited gross microleakage.
B
nent visible light-curable resin that contains urethane dimethacrylate, radiopaque filler, pigments, and initiators. Ketac-Silver is a glass ionomer with silver fused to the surface of the glass particles by a sintering process and is known as a cermet cement. The purpose of this in vitro study was to compare the ability of these materials to resist microleakage when used in endodontic access preparations.
leaching of endodontically treated teeth can greatly improve the esthetics of teeth that have become discolored.’ One method of accomplishing this treatment is the use of a “walking bleach” or internal bleaching agent. This requires sealing a paste of 30 percent hydrogen peroxide (Superoxol) and sodium perborate in the pulp chamber.* As these materials can be damaging to oral tissues, it is important to have a temporary restoration that provides an effective seal against microleakage. Also, ingress of oral fluids via microleakage may complicate successful bleaching making acceptable esthetics difficult to achieve.3-4 Temporary restorative materials are also used in endodontics to seal access preparations between appointments and prior to placement of a permanent restoration on completion of endodontic therapy. These interim restorations are placed to prevent contamination of the root canal system by oral fluids and microorganisms and to prevent leakage of intracanal medications into the oral cavity. Several materials have traditionally been used for this purpose, such as Cavit and IRM. Several newer materials are now available and are being utilized as well. TERM is one such material and is a one-compo-
METHOD Sixty extracted human molar teeth that had been stored in 10 percent buffered formalin were used in this investigation. Occlusal endodontic access preparations were performed on each tooth with a No. 4 round bur and % DT diamond bur using a high-speed handpiece and water coolant spray. The remaining coronal pulp tissue was removed with a spoon excavator, and the chamber was irrigated with saline and then dried with suction and cotton pellets. To simulate clinical conditions, the chamber floor was covered with a dry cotton pellet prior to placement of the restorative material. The teeth were randomly distributed into five groups of 12 teeth each. In the first group, Cavit (ESPE-Premier, Norristown, PA) was placed according to the manufacturer’s instructions and allowed to set. The second group was similarly treated with IRM (CaulWDentsply, Milford,DE). In the third group, the samples received a base of IRM, which was covered with approximately 3 mm of Cavit to form the “sandwich” restoration. The fourth group received the KetacSilver restorations after the enamel margins were
* S dDentist, USAF Hospital Bergsuorn, Bergstrom AFB, Texas ‘Associate Professor, Department of General Practice w i o r , Advanced Education in General Dentistry Program, University of Tau Health Science Center at San Antonio, San Antonio, Texas Address reprint requests to Dr. Robert L Cooley, General PracticeUrHSCSA, 7703 Floyd Curl Drive, San Antonio, TX 78284-7914 O 1990 B. C. Decker Inc.
166
Microleakage of Restorative Marerials
etched for 60 seconds with 37 percent orthophosphoric acid, rinsed for 30 seconds with an aidwater syringe, and treated with an unfilled bonding agent (Scotchbond 2, 3M Dental Products, St. Paul, MN). The bonding agent was polymerized for 40 seconds with an Optilux 400 unit (Demetron Research Corp, Danbury, CT). In the fifth group, TERM (CaulWDentsply) was placed according to the manufacturer’s instructions and light polymerized for 40 seconds with an Optilux 400 units. All samples were thermocycled in distilled water for 24 hours (800 cycles) at 6”C-60°C with a dwell time of 30 seconds. The roots were sealed with sticky wax and then the entire tooth coated with nail polish except for the restoration and l m m surrounding the restoration. The crowns of the teeth were immersed in S percent methylene blue for 4 hours, rinsed with tap water, and sectioned buccolingually through the restoration with a diamond saw (Isomet, Buehler Ltd, Evanston, IL). After sectioning, the cut surfaces were painted with clear nail polish to prevent dehydration. Three evaluators, blind to the identity of the groups, independently scored the degree of microleakage along the toothlrestoration interface using the following criteria (Fig. 1): 1-dye penetration from the occlusal surface up to one-half the distance to the pulpal floor, 2-dye penetration greater than one-half the distance to the pulpal floor, and +dye penetration extending horizontally along the pulpal floor. Each half of the sectioned specimen was rated, and the one with the greatest degree of dye penetration was recorded. The highest score from the three evaluators was used for statistical analysis.
Table 1. Microleakage Scores Scores for Each Moterial Material
0
Cavit IRM IRM-Cavit Ketac-Silver TERM
10
1
2
3 10
1
9
10
8
1
1
RESULTS The microleakage scores for each material are shown in Table 1. The rating indicating the most severe degree of microleakage from any of the three evaluators was used. Across all evaluations and materials, the three evaluators only disagreed three times and that was by 1 unit of scoring. Cavit exhibited no microleakage in any of the specimens, while the IRM-Cavit “sandwich” had only one specimen with a rating of “2,” and TERM had one specimen with a rating of 1” and one with a “2.” All of the IRM and Ketac-Silver specimens received a “3” score, which was the most severe degree of microleakage (Figs. 2-6). When the data was subjected to statistical analysis (Mann-Whitney U), IRM and Ketac-Silver had significantly more leakage than the other three materials (p < 0.01). The microleakage results obtained from TERM, Cavit, and the IRM-Cavit “sandwich” were not significantly different. “
DISCUSSION The need for a temporary endodontic filling material that resists microleakage of oral fluids is obvious.
Figure 2. Cavit specimen showing penetration of the dye into the material but no microleakage along the tooth-restoration interface.
Figure 1. Scoring criteria used by the evaluators. 167
JOURNAL OF ESTHETIC DENTISTRYNOLUME 2, NUMBER 6 Noc,ember/Derember 1990
Figure 5. Ketac-Silver restoration with dye leakage completely around the restoration and into the pulp chamber.
Figure 3. IRM-Cavit “sandwich” specimen also showing penetration of the dye into the material.
Ludlow7 evaluated microleakage with silver nitrate using Cavit, Cavit-G, and TERM. TERM demonstrated significantly less leakage after thermocycling. Pashley et al* showed leakage with IRM and ZOE after thermocycling using various powdertliquid ratios, though thinner mixes fared somewhat better. Since the start of this study, three similar investigations, which add to the conflicting results cited above, have been published on microleakage of temporary endodontic restorations. In a fuschin dye microleakage study, Jones et aP found Ketac-Silver allowed virtually no leakage, whereas IRM and TERM showed leakage ranging from minimal to extensive after thermocycling. Barkhordar and Stark10 demonstrated excellent sealing with Cavit and TERM, but poor sealing with IRM after thermocycling. Bobotis et all1 evaluated seven materials for microleakage with an apparatus that placed fluid under pressure within the pulp chamber and created the
Figure 4. IRM specimen demonstrating microleakage of the dye complerely around the restoration and into the pulp chamber.
This study found that TERhP, Cavit, and the IRM-Cavit “sandwich” to be superior in resisting microleakage. However, there have been a number of other in vitro studies that have evaluated microleakage in currently available products. Friedman et a l 5 evaluated microleakage of radiosodium from within the pulp chambers sealed with IRM, 20% Cavit-G, and Cavidentin and found that zincoxide eugenol products showed less microleakage than the others. Anderson et al6 demonstrated excellent s a g with TERM and CaVit and significant l e d w e with IRM after 7 days of thermal stress. Hermsen and
Figure 6. TERM restoration with only slight leakage at the occlusd margin. 168
Microleakage of Restorative Materials
potential for microleakage out of the tooth. After 8 weeks Cavit, TERM, and Fuji I1 demonstrated virtually leakproof seals while IRM and polycarboxylate cement showed the greatest leakage.
CONCLUSIONS Five materials were evaluated for microleakage when used as temporary endodontic restorations. TERM, Cavit, and the IRM-Cavit “sandwich” had virtually no leakage and significantly less than IRM or Ketac-Silver.
REFERENCES Howell RA. Bleaching discoloured root-filled teeth. Br Dent J 1980;148:159-162. Nutting E, Poe G. Chemical bleaching of discolored endodontically treated teeth. Dent Clin North Am 1967;1 1:65 5-662. Brown G. Factors influencing successful bleaching of the discolored root-filled tooth. Oral Surg Oral Med Oral Pathol 1965;20:238-244.
4. Nutting E, Poe G. A new combination for bleaching teeth. J S Calif Dent Assoc I963;31:289-334. 5. Friedman S, Shani J, Stabholz A, Kaplawi J. Comparative sealing ability of temporary filling materials evaluated by leakage of radiosodium. Int Endodont J 1986;19:187193. 6. Anderson R, Powell B, Pashley D. Microleakage of three temporary endodontic restorations. J Endodont 1988;14: 497-501. 7 . Hermsen K, Ludlow M. An in-vitro investigation comparing the marginal leakage of Cavit, Cavit-G, and TERM. Gen Dent 1989;37:214-217. 8. Pashley E, Tao L, Pashley D. T h e sealing properties of temporary filling materials. J Prosthet Dent I988;60: 292-291. 9. Jones K, Fruithandler R, Berg J. Microleakage of interim endodontic filling materials. Am J Dent 1990;3:? 1-74. 10. Barkhordar R, Stark M. Sealing ability of intermediate restorations and cavity design used in endodontics. Oral Surg Oral Med Oral Pathol 1990;69:97-101. 11. Bobotis H, Anderson R, Pashley D, Pantera E. A microleakage study of temporary restorative materials used in endodontics. J Endodont 1989;15:569-572.
