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Pulpal response to tricalcium phosphate as a capping agent
Pulpal response to tricalcium phosphate as a capping agent A. A. Chohayeb, J. C. Adrian, and K, Salamat, Washington, D.C. COLLEGE
OF DENTISTRY,
HOWARD
UNIVERSITY
The purpose of this study was to evaluate tricalcium phosphate (TCP) as a pulp-capping agent. Two adult male beagle dogs were used for this investigation. Class I cavities were prepared in the posterior teeth and Class V cavities in the anterior teeth. With the use of a rubber dam and high speed wtth water coolant, minimal pulp exposures were created in both the experimental and control teeth, by means of a W round bur. Zinc oxide-eugenol was the temporary filling material used to restore all cavities. In each dog, five teeth served as control and were capped with the use of calcium hydroxide. In one dog, 10 teeth from two quadrants were capped with the tested material (TCP). In the other dog, 11 teeth were capped with TCP. Four teeth from the fourth quadrant in each dog were capped with a mixture of calcium hydroxide and TCP in a ratio of 1: 1 by weight (50/50 group.) The two dogs were killed after 70 days. The histologic evaluation of the response to the capping agents and at the exposure site was recorded. A total of 39 teeth were evaluated in this study. It was found that TCP as a capping agent precipitated the highest mean inflammatory response and also demonstrated the highest percentage of reparative dentin formation. (ORAL SURC ORAL MED ORAL PATHOL 1991;71:343-5)
P
faff in 1756l recommendedcappingexposedpulps by using a gold plate over the exposuresite. Since then, severalagents have been used over the years with conflicting observationsreported on the advantagesand the disadvantagesof each agent. Herman2in 1930introduced calcium hydroxide as a capping agent. This agent was “successful,” according to an evaluationby Zander.3But Seltzer and Bender4stated that the osteogenicpotential of calcium hydroxide might causecompleteobliteration of the pulp chamber and root canal(s) and noted that occasionallythis agent led to metaplasiaof the odontoblasts and resultant internal resorption in the root canal(s). According to Tronstad and Mjor,s calcium hydroxide has no beneficialeffectin cappinginflamedpulps. They showedmore successin capping inflamedpulps when using zinc oxide and eugenol. In addition, Rowe6 reported that zinc oxide and eugenol paste showedthe mostconsistentsuccessfulresultsascompared to calcium hydroxide powder and other agents. But a contrastingreport from Langer and coworkers’ showedthat zinc oxide and eugenol paste provoked chronic pulpitis, odontoblastic damage, and pulpal necrosis. Bhaskar and others8 demonstrated that isobutyl 7/15/16472
cyanoacrylate,when usedas a capping agent,caused lesssevereinflammationof the pulp than calcium hydroxide, and the new dentin bridge occurred directly against the cyanoacrylate with no zone of necrosis. Similar results were reported by Berkman and others.9According to Stanley,‘Omicroabscessesare more frequent in the calcium hydroxide-treated group than in the isobutyl cyanoacrylats-treated group. However, Spangberg and coworkers” reported that isobutyl cyanoacrylate was cytotoxic in vitro. This material, to date,hasnot beenapprovedfor use as a capping agent. According to Heller and associates,12tricalcium phosphate(TCP) when usedas a pulp-cappingagent was successfulin promoting a contiguous calcified bridge. The pulpal tissuethat was in immediatecontact with the bridge showed very minimal or no inflammatoryresponse(IR) in 2 1 of 22 specimens.By contrast, 3 of 7 control pulps with a calcium hydroxide paste demonstratedpulpal necrosis. The purposeof this study was to evaluatethe use of TCP as a pulp-capping agent and to compare it with calcium hydroxide and also a mixture of TCP and calcium hydroxide (1:l by weight). MATERIAL
AND METHODS
Two adult male beagledogs were usedfor this investigation.ClassI cavitieswere preparedin the pos343
344 Chohayeb, Adrian, and Salamat Table
ORAL SURG ORAL MED ORAL PATHOL March 1991
I. Pulpal responseto capping agents
Control (calcium hydroxide) so/so
1.5
1.5
0.75
0
TCP
2.5
3
DISCUSSiON
5110 (50%) 318 (38%) 18/21 (86%)
terior teeth, and Class V cavities were prepared in the anterior teeth. A minimal pulp exposure was created in the experimental and control teeth with a No. lh round bur with the use of high speedwith water coolant. Zinc oxide-eugenol was used as the temporary filling material to restore all preparations. In each dog, five control teeth were capped with calcium hydroxide. In one dog, five teeth from each of two quadrants were capped with TCP. In the other dog, 11 teeth from two separate quadrants were capped with TCP. Four teeth from the fourth quadrant of each dog were cappedwith a mixture of calcium hydroxide and TCP in a 1:l ratio by weight (SO/SOgroup). The two dogswere killed after 70 days by intravenous infusion of sodium pentobarbital. The histologic evaluation of the pulpal reaction to the capping material was done according to modified criteria used by Pereira and Stanley13: 0 = no IR 1 = mild IR 2 = moderate IR 3 = severe IR The presenceor absenceof reparative dentin (RD) was recorded. RESULTS
Thirty-nine pulp-capped teeth were evaluated by light microscopy in this study: 21, TCP; 10, controls; 8, 50150. The following features of the pulpal responsewere recorded: IR and RD formation. Control teeth. The mean and the median of the IR of the control teeth were identical at 1.5 (Table I). The formation of RD was identified in five of 10 specimens. SO/50teeth. The IR of these teeth had a mean of 0.75 and a median of 0. The formation of RD wasseen in three of eight pulps (Table I). TCP teeth. The IR in these teeth was noted to have a mean of 2.5 and a median of 3.0. RD was observed in 18 of 21 teeth (Table I).
In contrast to the reports of Heller and coworkers12 and Boone and Kafrawy, I4 we found that the IR of the pulp to TCP was marked (mean 2.5). However, we also found, as did Heller and coworkers12and Boone and Kafrawy, I3 that RD formation in these same teeth was very prominent (86%). It can be noted also that when the IR was reduced as seenin the calcium hydroxide controls (mean 1.5) and 50/50 group (mean 0.75), the percentage of RD formation was also reduced proportionally. Stanley I5 suggeststhat RD formation is essential to maintaining the health and integrity of the pulp tissue after exposure. Although we observed a high percentage of TCP-capped teeth with RD, the corresponding high incidence of severe inflammation was a cause of concern for us. Perhaps our period before killing of the animals was too short or the composition, application, or particle size of our TCP was significantly different from that of other investigators. CONCLUSION
This study showed that TCP when used as a pulpcapping agent demonstrated a marked ability to elicit the formation of RD at the exposure site. However, within the parameters of this investigation, TCP also precipitated increased IR. Further studies are recommendedto investigate the use of different vehicles and/or additives with TCP to reduce the IR while maintaining its ability to promote RD formation at the exposure site. REFERENCES 1. Pfaff P, quoted by Atkinson WH. The preservation of exposed dental pulps. Dental Cosmos 1865;VI:425-9. 2. Herman BW. Dentinobliteration der Wurzel Kanale Nach Behandlung mit Calcium. Zahnartzl Resch 1930;39:888. 3. Zander HA. Reaction of the pulp to calcium hydroxide. J Dent Res 1939;18:373. 4. Seltzer S, Bender IB. The dental pulp. Biologic considerations in dental procedures. 2nd ed. Chap. 14. Philadelphia: JB Lippincott Co., 1975. 5. Tronstad L, Mjor IA. Capping the inflamed pulp. ORAL SURG ORAL MED ORAL PATHOL 1972;34:477-85. 6. Rowe AHR. Reaction of the rat molar pulp to various materials. Br Dent J 1967;122:291. 7. Langer M, Ulmansky M, Sela J. Behavior of human dental pulp to Calxyl with or without zinc oxide eugenol. Arch Oral Biol 1970;15:189-94. 8. Bhaskar SN, Cuttright D, Boyers R, Margetis P. Pulp capping with isobutyl cyanoacrylate. J Am Dent Assoc 1969:79:640. 9. Berkman M, Cuccoto F, Levin M, Brunelle L. Pulpal response to isobutyl cyanoacrylate in human teeth. J Am Dent Assoc 1971;83:140. 10. Stanley HR. Dycal therapy for pulp exposure. ORAL SURG ORAL MED ORAL PATHOL 1972;34:818.
11. Spangberg L, Rodrigues R, Langeland K. Biological effects of dental material. Effects of isobutyl cyanoacrylate on HeLa cells in vitro. ORAL SURG ORAL MED ORAL PATHOL 1974; 37:438.
Pulpal response to tricalcium phosphate 345
Volume 71 Number 3 12. Heller AL, Loenigs JF, Brilliant JD, Melfi RC, Driskell TD. Direct pulp capping of permanent teeth in primates using a resorbable form of tricalcium phosphate ceramic. J Endod
15. Stanley HR. Human pulp responseto operative dental procedures. 1sted.Gainesville, Florida: Storter Printing Co, 1976;3l46.
1975;1:95.
13. Pereira JC, Stanley HR. Pulp capping: influence of the exposure site on pulp healing-histologic radiographic study in dog’s pulp. J Endodont. 1981;7:213-23. 14. Boone ME, Kafrawy AH. Pulp reaction to a tricalcium phosphate ceramic capping agent. ORAL SURG ORAL MED ORAL PATHOL
1979;41:369.
Reprint requests to:
A. A. Chohayeb College of Dentistry Howard University 600 “w” Street NW Washington, DC 20059
OF DENTISTRY,
HOWARD
UNIVERSITY
The purpose of this study was to evaluate tricalcium phosphate (TCP) as a pulp-capping agent. Two adult male beagle dogs were used for this investigation. Class I cavities were prepared in the posterior teeth and Class V cavities in the anterior teeth. With the use of a rubber dam and high speed wtth water coolant, minimal pulp exposures were created in both the experimental and control teeth, by means of a W round bur. Zinc oxide-eugenol was the temporary filling material used to restore all cavities. In each dog, five teeth served as control and were capped with the use of calcium hydroxide. In one dog, 10 teeth from two quadrants were capped with the tested material (TCP). In the other dog, 11 teeth were capped with TCP. Four teeth from the fourth quadrant in each dog were capped with a mixture of calcium hydroxide and TCP in a ratio of 1: 1 by weight (50/50 group.) The two dogs were killed after 70 days. The histologic evaluation of the response to the capping agents and at the exposure site was recorded. A total of 39 teeth were evaluated in this study. It was found that TCP as a capping agent precipitated the highest mean inflammatory response and also demonstrated the highest percentage of reparative dentin formation. (ORAL SURC ORAL MED ORAL PATHOL 1991;71:343-5)
P
faff in 1756l recommendedcappingexposedpulps by using a gold plate over the exposuresite. Since then, severalagents have been used over the years with conflicting observationsreported on the advantagesand the disadvantagesof each agent. Herman2in 1930introduced calcium hydroxide as a capping agent. This agent was “successful,” according to an evaluationby Zander.3But Seltzer and Bender4stated that the osteogenicpotential of calcium hydroxide might causecompleteobliteration of the pulp chamber and root canal(s) and noted that occasionallythis agent led to metaplasiaof the odontoblasts and resultant internal resorption in the root canal(s). According to Tronstad and Mjor,s calcium hydroxide has no beneficialeffectin cappinginflamedpulps. They showedmore successin capping inflamedpulps when using zinc oxide and eugenol. In addition, Rowe6 reported that zinc oxide and eugenol paste showedthe mostconsistentsuccessfulresultsascompared to calcium hydroxide powder and other agents. But a contrastingreport from Langer and coworkers’ showedthat zinc oxide and eugenol paste provoked chronic pulpitis, odontoblastic damage, and pulpal necrosis. Bhaskar and others8 demonstrated that isobutyl 7/15/16472
cyanoacrylate,when usedas a capping agent,caused lesssevereinflammationof the pulp than calcium hydroxide, and the new dentin bridge occurred directly against the cyanoacrylate with no zone of necrosis. Similar results were reported by Berkman and others.9According to Stanley,‘Omicroabscessesare more frequent in the calcium hydroxide-treated group than in the isobutyl cyanoacrylats-treated group. However, Spangberg and coworkers” reported that isobutyl cyanoacrylate was cytotoxic in vitro. This material, to date,hasnot beenapprovedfor use as a capping agent. According to Heller and associates,12tricalcium phosphate(TCP) when usedas a pulp-cappingagent was successfulin promoting a contiguous calcified bridge. The pulpal tissuethat was in immediatecontact with the bridge showed very minimal or no inflammatoryresponse(IR) in 2 1 of 22 specimens.By contrast, 3 of 7 control pulps with a calcium hydroxide paste demonstratedpulpal necrosis. The purposeof this study was to evaluatethe use of TCP as a pulp-capping agent and to compare it with calcium hydroxide and also a mixture of TCP and calcium hydroxide (1:l by weight). MATERIAL
AND METHODS
Two adult male beagledogs were usedfor this investigation.ClassI cavitieswere preparedin the pos343
344 Chohayeb, Adrian, and Salamat Table
ORAL SURG ORAL MED ORAL PATHOL March 1991
I. Pulpal responseto capping agents
Control (calcium hydroxide) so/so
1.5
1.5
0.75
0
TCP
2.5
3
DISCUSSiON
5110 (50%) 318 (38%) 18/21 (86%)
terior teeth, and Class V cavities were prepared in the anterior teeth. A minimal pulp exposure was created in the experimental and control teeth with a No. lh round bur with the use of high speedwith water coolant. Zinc oxide-eugenol was used as the temporary filling material to restore all preparations. In each dog, five control teeth were capped with calcium hydroxide. In one dog, five teeth from each of two quadrants were capped with TCP. In the other dog, 11 teeth from two separate quadrants were capped with TCP. Four teeth from the fourth quadrant of each dog were cappedwith a mixture of calcium hydroxide and TCP in a 1:l ratio by weight (SO/SOgroup). The two dogswere killed after 70 days by intravenous infusion of sodium pentobarbital. The histologic evaluation of the pulpal reaction to the capping material was done according to modified criteria used by Pereira and Stanley13: 0 = no IR 1 = mild IR 2 = moderate IR 3 = severe IR The presenceor absenceof reparative dentin (RD) was recorded. RESULTS
Thirty-nine pulp-capped teeth were evaluated by light microscopy in this study: 21, TCP; 10, controls; 8, 50150. The following features of the pulpal responsewere recorded: IR and RD formation. Control teeth. The mean and the median of the IR of the control teeth were identical at 1.5 (Table I). The formation of RD was identified in five of 10 specimens. SO/50teeth. The IR of these teeth had a mean of 0.75 and a median of 0. The formation of RD wasseen in three of eight pulps (Table I). TCP teeth. The IR in these teeth was noted to have a mean of 2.5 and a median of 3.0. RD was observed in 18 of 21 teeth (Table I).
In contrast to the reports of Heller and coworkers12 and Boone and Kafrawy, I4 we found that the IR of the pulp to TCP was marked (mean 2.5). However, we also found, as did Heller and coworkers12and Boone and Kafrawy, I3 that RD formation in these same teeth was very prominent (86%). It can be noted also that when the IR was reduced as seenin the calcium hydroxide controls (mean 1.5) and 50/50 group (mean 0.75), the percentage of RD formation was also reduced proportionally. Stanley I5 suggeststhat RD formation is essential to maintaining the health and integrity of the pulp tissue after exposure. Although we observed a high percentage of TCP-capped teeth with RD, the corresponding high incidence of severe inflammation was a cause of concern for us. Perhaps our period before killing of the animals was too short or the composition, application, or particle size of our TCP was significantly different from that of other investigators. CONCLUSION
This study showed that TCP when used as a pulpcapping agent demonstrated a marked ability to elicit the formation of RD at the exposure site. However, within the parameters of this investigation, TCP also precipitated increased IR. Further studies are recommendedto investigate the use of different vehicles and/or additives with TCP to reduce the IR while maintaining its ability to promote RD formation at the exposure site. REFERENCES 1. Pfaff P, quoted by Atkinson WH. The preservation of exposed dental pulps. Dental Cosmos 1865;VI:425-9. 2. Herman BW. Dentinobliteration der Wurzel Kanale Nach Behandlung mit Calcium. Zahnartzl Resch 1930;39:888. 3. Zander HA. Reaction of the pulp to calcium hydroxide. J Dent Res 1939;18:373. 4. Seltzer S, Bender IB. The dental pulp. Biologic considerations in dental procedures. 2nd ed. Chap. 14. Philadelphia: JB Lippincott Co., 1975. 5. Tronstad L, Mjor IA. Capping the inflamed pulp. ORAL SURG ORAL MED ORAL PATHOL 1972;34:477-85. 6. Rowe AHR. Reaction of the rat molar pulp to various materials. Br Dent J 1967;122:291. 7. Langer M, Ulmansky M, Sela J. Behavior of human dental pulp to Calxyl with or without zinc oxide eugenol. Arch Oral Biol 1970;15:189-94. 8. Bhaskar SN, Cuttright D, Boyers R, Margetis P. Pulp capping with isobutyl cyanoacrylate. J Am Dent Assoc 1969:79:640. 9. Berkman M, Cuccoto F, Levin M, Brunelle L. Pulpal response to isobutyl cyanoacrylate in human teeth. J Am Dent Assoc 1971;83:140. 10. Stanley HR. Dycal therapy for pulp exposure. ORAL SURG ORAL MED ORAL PATHOL 1972;34:818.
11. Spangberg L, Rodrigues R, Langeland K. Biological effects of dental material. Effects of isobutyl cyanoacrylate on HeLa cells in vitro. ORAL SURG ORAL MED ORAL PATHOL 1974; 37:438.
Pulpal response to tricalcium phosphate 345
Volume 71 Number 3 12. Heller AL, Loenigs JF, Brilliant JD, Melfi RC, Driskell TD. Direct pulp capping of permanent teeth in primates using a resorbable form of tricalcium phosphate ceramic. J Endod
15. Stanley HR. Human pulp responseto operative dental procedures. 1sted.Gainesville, Florida: Storter Printing Co, 1976;3l46.
1975;1:95.
13. Pereira JC, Stanley HR. Pulp capping: influence of the exposure site on pulp healing-histologic radiographic study in dog’s pulp. J Endodont. 1981;7:213-23. 14. Boone ME, Kafrawy AH. Pulp reaction to a tricalcium phosphate ceramic capping agent. ORAL SURG ORAL MED ORAL PATHOL
1979;41:369.
Reprint requests to:
A. A. Chohayeb College of Dentistry Howard University 600 “w” Street NW Washington, DC 20059