- Email: [email protected]
Assessment of coronal microleakage in intermediately restored endodontic access cavities
Assessment of coronal microleakage in intermediately restored endodontic access cavities Sanjay Tewari, MDS,a and Shikha Tewari, MDS,b Rohtak, Haryana, India GOVERNMENT DENTAL COLLEGE
Objective. The purpose of this in vitro study was to evaluate the coronal microleakage in endodontic access cavities restored with Kalzinol (zinc oxide eugenol, De Trey, Dentsply Dental Products of India Ltd) and a zinc oxide eugenol (ZOE) intermediate restorative material at different intervals. Study design. Restored access cavities were immersed in 2% freshly prepared methylene blue dye, and dye penetration was evaluated at 1-, 2-, 4-, and 7-day intervals. Results. ZOE cement displayed dye penetration throughout the complete depth of the restoration, reaching the pulp chamber by the second day, whereas Kalzinol produced leakage reaching the pulp chamber on the fourth day. Conclusion. Results indicated that none of the ZOE formulations tested could predictably produce a fluid-tight seal even up to the fourth day. We therefore recommend early replacement of these restorations during and after endodontic treatment to produce a better prognosis. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;93:716-9)
Complete sealing of the endodontic access opening between appointments and after completion of therapy is an essential element in achieving endodontic success. For longer than 60 years, zinc oxide eugenol (ZOE) cement has been recommended as an excellent temporary filling material to restore the access preparation.1,2 Many studies have shown that it provides a leakproof seal.3-7 However, some recent studies have reported that it does demonstrate leakage when evaluated with an in vitro testing procedure.8-11 By altering the ratio of powder to liquid (P/L), the sealing ability of ZOE materials can be improved, and it has been demonstrated that lower P/L ratio has a significant role in decreasing the microleakage.11,12 Pashley et al12 and Jacquot et al13 observed that although ZOE seals the cavity well against oral fluids, leakage tends to increase over time. This study was undertaken to determine the time up to which these cements prevent microleakage in endodontic access cavities in order to specify the proper time for their replacement. MATERIAL AND METHODS Eighty recently extracted human, caries-free molars were selected for their occlusal integrity and stored in a
Professor and Head, Department of Operative Dentistry and Endodontics, Government Dental College, Rohtak, Haryana, India. b Reader and Head, Department of Community Dentistry, Government Dental College, Rohtak, Haryana, India. Received for publication May 23, 2001; returned for revision Oct 26, 2001; accepted for publication Nov 29, 2001. Copyright © 2002 by Mosby, Inc. 1079-2104/2002/$35.00 ⫹ 0 7/15/122347 doi:10.1067/moe.2002.122347
716
saline. Endodontic access cavities were prepared with standard-size burrs, and pulp chamber contents were removed. No attempt was made to remove material from the root canal. A dry cotton pellet was placed in the pulp chamber, leaving a 4- to 5-mm space for the temporary restoration. The intermediate restorative materials that were selected for this study were ZOE and Kalzinol (zinc oxide eugenol, De Trey, Dentsply Dental Products of India Ltd). Kalzinol is a zinc oxide eugenol– based cement, reinforced with polystyrene polymer. The teeth were randomly divided into two groups of 40 teeth each, with each group receiving one of the aforementioned materials to seal the access cavity. These cements were mixed to a thick putty-like consistency (6:1 P/L ratio), following the manufacturers’ instructions, and placed into the access cavity with finger pressure. All the teeth were radiographed subsequent to filling to verify the extent and the quality of coronal restoration. Samples were then placed in 100% relative humidity, and 10 teeth of each group were subjected to dye leakage evaluation at 1-, 2-, 4-, or 7-day intervals. Teeth were dried and coated with multiple layers of sticky wax, leaving only the coronal access exposed. Positive controls were coated with sticky wax in a similar fashion, but no restorative material was placed. The negative controls were completely coated with wax over a cotton pellet in the pulp chamber. All the samples were then immersed in freshly prepared 2% methylene blue dye for up to 7 days, washed with tap water, left to air dry for 24 hours, and finally sectioned mediodistally with an Isomet saw (Buehler Ltd., Lake Bluff, Ill). Each specimen was examined under a stereomicroscope at 6⫻ magnification, and the
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ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 93, Number 6
Table I. Scoring of leakage Degree of leakage 0 1 2 3 4
Table III. Statistical analysis of leakage scores: treatment groups versus different intervals
Depth of penetration Comparison
No staining Staining up to one-third of the cavity wall Staining from one-third to two-thirds of the wall Staining more than two-thirds of the wall Dye penetrating to cotton pellet in pulp chamber
Z calculated values
P
Difference
2.88 3.76 0.8 3.44 0.8 2.88 3.76
⬍.01 ⬍.01 ⬎.05 ⬍.01 ⬎01 ⬍.01 ⬍.01
Significant Significant Not significant Significant Not significant Significant Significant
1st day: ZOE and Kalzinol 2nd day: ZOE and Kalzinol 4th day: ZOE and Kalzinol ZOE: 1st and 2nd days ZOE: 2nd and 4th days Kalzinol: 1st and 2nd days Kalzinol: 2nd and 4th days
Table II. Leakage score at different intervals in both experimental groups Leakage score: zinc oxide eugenol
Leakage score: Kalzinol
Day
n
0
1
2
3
4
n
0
1
2
3
4
1st day 2nd day 4th day 7th day
10 10 10 10
0 0 0 0
0 0 0 0
7 0 0 0
3 2 0 0
0 8 10 10
10 10 10 10
0 0 0 0
6 0 0 0
4 7 0 0
0 3 2 0
0 0 8 10
extent of leakage was scored according to the criteria shown in Table I. The data were analyzed using the MannWhitney U-test to determine whether there was any statistically significant difference between the pairs of groups. RESULTS Results of this study demonstrated variable leakage patterns in both groups at all intervals. These results are summarized in Table II. There was a statistically significant difference in dye leakage between ZOE and Kalzinol on the first and second days, with Kalzinol showing better sealability, whereas on the fourth day no significant difference was found between the two groups. On the seventh day, both ZOE and Kalzinol exhibited complete dye penetration into the pulp chamber in all the samples. Microleakage observed in ZOE was significantly more on the second day than on the first day, whereas on the fourth day, no significant difference from the second day was observed. With Kalzinol, the severity of the leakage increased from the first day onward, with statistically significant differences in dye penetration between the first and second days and the second and fourth days. DISCUSSION For evaluation of microleakage, the methylene blue dye penetration method was used in this study because it is a simple and inexpensive technique and has displayed better penetration results than eosin14 or the radioisotope tracers 45 Ca-labeled calcium chloride, 14C-labeled urea, and 125Ilabeled albumin.15,16 The results of this study indicated that penetration of dye into the pulp chamber was prevented by ZOE and reinforced
ZOE restoration of endodontic access preparations only up to the first day and the third day, respectively. Whereas there have been no published reports suggesting the time up to which these restorations prevented microleakage, many previous studies have demonstrated extensive leakage in ZOE preparations during 3- to 7-day testing periods.8-15 These observations, however, do not concur with the report of Guerra et al,5 who found no leakage to minimal leakage in 2- to 4-mm-thick ZOE bases over gutta-percha obturation up to 1 week. Bergenholtz et al6 and Brannstrom,7 while evaluating bacterial leakage around restorations, demonstrated a bacteria-tight seal in ZOE restorations. Brannstrom,7 in his extensive work, even recommended sealing ZOE cement over other restorative materials to provide a bacteria-tight seal for evaluation of pulp response in experimental studies. The findings of the present study suggest that the bacteria-tight seal provided by ZOE cement may not be a result of its sealing properties but simply of its antimicrobial effect. ZOE cement seals the cavity well against the ingress of oral fluids, at least for a short time, mainly because of its better adaptation to the cavity wall, its coefficient of thermal expansion similar to the tooth, and its hygroscopic and antimicrobial properties.17,18 The extensive leakage in this study, from the second day onward in ZOE and from the fourth day onward in Kalzinol, could be attributed to dissolution or disintegration of ZOE because of moisture contact. Set ZOE cement consists of zinc oxide powder bonded together with a loose matrix of zinc eugenolate. This reaction is reversible, and zinc eugenolate is easily hydrolyzed by moisture to eugenol and zinc hydroxide.18 The better sealing ability displayed by reinforced
718 Tewari and Tewari
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY June 2002
Fig 1. Photograph showing grade-1 leakage reaching up to onethird of cavity wall in Kalzinol restoration on the first day.
Fig 3. Photograph showing grade-4 leakage reaching the pulp chamber in ZOE cement restoration on the second day.
Fig 2. Tooth section showing grade-3 leakage staining more than two-thirds of wall in ZOE cement restoration on the first day.
Fig 4. Photograph showing grade-4 leakage reaching the pulp chamber in Kalzinol restoration on the fourth day.
ZOE cement is in accordance with the previous study of Jenderson and Phillips19 and could be related to its better resistance to dissolution. In Kalzinol, reinforcement of ZOE with polystyrene polymer significantly improves its
abrasion resistance and compressive strength and decreases dissolution.19 In order to correlate the results to clinical use, thermocycling was not performed in this study. Jacquot et al13
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ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 93, Number 6
cautioned against the use of thermocycling for in vitro dye evaluation, because thermocycling damages ZOE preparations more than other materials. Tamse et al14 reported severe leakage in 3 days in 8 out of 10 samples with Kalzinol restorations, and Kazemi et al15 demonstrated mean dye penetration of 4.87 mm in just 24 hours in 5-mm bulk IRM restorations when subjected to thermocycling. In this study, the thickness of the ZOE restorations was at least 4 mm, complying with the recommendation of Webber et al.20 However, the P/L ratio was 6:1, to form a thick putty-like consistency. The thinner mixes (2:1 P/L ratio), which display the best seal as reported by Pashley et al,12 were not found adequate to seal access cavities. They were readily washed out under clinical conditions because of their prolonged setting time and inferior physical properties. This 2:1 P/L ratio is used in ZOE endodontic sealers and may be the reason why ZOE sealers perform well both in clinical and in-vitro studies. Within the limits of this study, we conclude that ZOE cement does not provide even a short-term adequate coronal seal in endodontic access cavities. The findings of this study demonstrate extensive dye penetration in 4- to 5-mm bulk ZOE restoration after just 1 day for ZOE and 3 days for Kalzinol. This suggests that further evaluation of the sealing properties of these cements is needed in order to verify whether the clinical success of ZOE is the result of its sealing properties or antibacterial properties.21 REFERENCES 1. Grossman LI. A study of temporary fillings as hermetic sealing agents. J Dent Res 1939;18:67-71. 2. Weine FS. Endodontic therapy. 4th ed. St. Louis: CV Mosby; 1989. p. 354-8. 3. Parris L. Kapsimalis P. The effect of temperature change on the sealing properties of temporary filling materials. Oral Surg Oral Med Oral Pathol 1960;13:982-9. 4. McInerney ST, Zillich R. Evaluation of internal sealing ability of three materials. J Endod 1992;18:376-8. 5. Guerra JA, Skribner JE., Lin LM. Influence of a base on coronal microleakage of post prepared teeth. J Endod 1994;20:589-91.
6. Bergenholtz G, Joesche WJ, Syed SA. Bacterial leakage around dental restorations: its effect on the dental pulp. J Oral Pathol 1982;11:439-50. 7. Brannstrom M. Dentin and pulp in restorative dentistry. London: Wolfe Medical Publication Ltd; 1982. p. 87-90. 8. Bobotis HG, Anderson RW, Pashley DH, Pantera EA. A microleakage study as temporary restorative materials used in endodontics. J Endod 1989;15:569-72. 9. Barkhordar RA, Stark MM. Sealing ability of intermediate restorations and cavity design used in endodontics. Oral Surg Oral Med Oral Pathol 1990;69:99-101. 10. Lee YC, Yang SF, Hwang YF, Chueh LH, Chung KH. Microleakage of endodontic temporary restorative materials. J Endod 1993;19:516-20. 11. Anderson RW, Powel BJ, Pashley DH. Microleakage of three temporary endodontic restorations. J Endod 1988;14:497-501. 12. Pashley EL, Tao L, Pashley DH. The sealing properties of temporary filling materials. J Prosthet Dent 1988;60:292-7. 13. Jacquot BM, Panghi MM, Steinmetz P, G’Sell C. Microleakage of Cavit, Cavit W, Cavit G, and IRM by impedance spectroscopy. Int Endod J 1996;29:256-61. 14. Tamse A, Ben-Amer A, Gover A. Sealing properties of temporary filling materials used in endodontics. J Endod 1982;8: 322-5. 15. Kazemi RB, Safavi KE, Spanberg LSW. Assessment of marginal sealability and permeability of an interim restorative endodontic material. Oral Surg Oral Med Oral Pathol 1994;78:788-96. 16. Matloff IR, Jensen JR, Singar L, Tabibi A. A comparison of methods used in root canal sealability studies. Oral Surg Oral Med Oral Pathol 1982;53:203-8. 17. Phillips RW. Skinners science of dental materials. 8th ed. Philadelphia: WB Saunders Co; 1982. p. 318-9. 18. Hume WR. The pharmacologic and toxicological properties of zinc oxide eugenol. J Am Dent Assoc 1986;113:789-91. 19. Jenderson M, Phillips RW, Swartz ML. A comparative study of four zinc oxide eugenol formulations as restorative material. J Prosthet Dent 1969;21:176-83. 20. Webber RT, del Rio CE, Brady JM, Segall RO. Sealing quality of a temporary filling material. Oral Surg Oral Med Oral Pathol 1978;46:123-30. 21. Chohayeb AD, Bassiouny MA. Sealing ability of intermediate restorative used in endodontics J Endod 1985;11:241-4. Reprint requests: Sanjay Tewari, MDS 6/6J Medical Enclave Pt.B.D.Sharma P.G.I.M.S. Rohtak 124001 Haryana India [email protected]
AVAILABILITY OF JOURNAL BACK ISSUES As a service to our subscribers, copies of back issues of Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics for the preceding 5 years are maintained and are available for purchase from the publisher, Mosby, until inventory is depleted. The following quantity discounts are available: 25% off on quantities of 12 to 23; one third off on quantities of 24 or more. Please write to Mosby, Subscription Customer Service, 6277 Sea Harbor Dr, Orlando, FL 32887, or call 800-654-2452 or 407-345-4000 for information on availability of particular issues and prices. If unavailable from the publisher, photocopies of complete issues are available from Bell & Howell Information and Learning, 300 N Zeeb Rd, Ann Arbor, MI 48106-1346; (734) 761-4700 or (800) 521-0600.
Objective. The purpose of this in vitro study was to evaluate the coronal microleakage in endodontic access cavities restored with Kalzinol (zinc oxide eugenol, De Trey, Dentsply Dental Products of India Ltd) and a zinc oxide eugenol (ZOE) intermediate restorative material at different intervals. Study design. Restored access cavities were immersed in 2% freshly prepared methylene blue dye, and dye penetration was evaluated at 1-, 2-, 4-, and 7-day intervals. Results. ZOE cement displayed dye penetration throughout the complete depth of the restoration, reaching the pulp chamber by the second day, whereas Kalzinol produced leakage reaching the pulp chamber on the fourth day. Conclusion. Results indicated that none of the ZOE formulations tested could predictably produce a fluid-tight seal even up to the fourth day. We therefore recommend early replacement of these restorations during and after endodontic treatment to produce a better prognosis. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;93:716-9)
Complete sealing of the endodontic access opening between appointments and after completion of therapy is an essential element in achieving endodontic success. For longer than 60 years, zinc oxide eugenol (ZOE) cement has been recommended as an excellent temporary filling material to restore the access preparation.1,2 Many studies have shown that it provides a leakproof seal.3-7 However, some recent studies have reported that it does demonstrate leakage when evaluated with an in vitro testing procedure.8-11 By altering the ratio of powder to liquid (P/L), the sealing ability of ZOE materials can be improved, and it has been demonstrated that lower P/L ratio has a significant role in decreasing the microleakage.11,12 Pashley et al12 and Jacquot et al13 observed that although ZOE seals the cavity well against oral fluids, leakage tends to increase over time. This study was undertaken to determine the time up to which these cements prevent microleakage in endodontic access cavities in order to specify the proper time for their replacement. MATERIAL AND METHODS Eighty recently extracted human, caries-free molars were selected for their occlusal integrity and stored in a
Professor and Head, Department of Operative Dentistry and Endodontics, Government Dental College, Rohtak, Haryana, India. b Reader and Head, Department of Community Dentistry, Government Dental College, Rohtak, Haryana, India. Received for publication May 23, 2001; returned for revision Oct 26, 2001; accepted for publication Nov 29, 2001. Copyright © 2002 by Mosby, Inc. 1079-2104/2002/$35.00 ⫹ 0 7/15/122347 doi:10.1067/moe.2002.122347
716
saline. Endodontic access cavities were prepared with standard-size burrs, and pulp chamber contents were removed. No attempt was made to remove material from the root canal. A dry cotton pellet was placed in the pulp chamber, leaving a 4- to 5-mm space for the temporary restoration. The intermediate restorative materials that were selected for this study were ZOE and Kalzinol (zinc oxide eugenol, De Trey, Dentsply Dental Products of India Ltd). Kalzinol is a zinc oxide eugenol– based cement, reinforced with polystyrene polymer. The teeth were randomly divided into two groups of 40 teeth each, with each group receiving one of the aforementioned materials to seal the access cavity. These cements were mixed to a thick putty-like consistency (6:1 P/L ratio), following the manufacturers’ instructions, and placed into the access cavity with finger pressure. All the teeth were radiographed subsequent to filling to verify the extent and the quality of coronal restoration. Samples were then placed in 100% relative humidity, and 10 teeth of each group were subjected to dye leakage evaluation at 1-, 2-, 4-, or 7-day intervals. Teeth were dried and coated with multiple layers of sticky wax, leaving only the coronal access exposed. Positive controls were coated with sticky wax in a similar fashion, but no restorative material was placed. The negative controls were completely coated with wax over a cotton pellet in the pulp chamber. All the samples were then immersed in freshly prepared 2% methylene blue dye for up to 7 days, washed with tap water, left to air dry for 24 hours, and finally sectioned mediodistally with an Isomet saw (Buehler Ltd., Lake Bluff, Ill). Each specimen was examined under a stereomicroscope at 6⫻ magnification, and the
Tewari and Tewari 717
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 93, Number 6
Table I. Scoring of leakage Degree of leakage 0 1 2 3 4
Table III. Statistical analysis of leakage scores: treatment groups versus different intervals
Depth of penetration Comparison
No staining Staining up to one-third of the cavity wall Staining from one-third to two-thirds of the wall Staining more than two-thirds of the wall Dye penetrating to cotton pellet in pulp chamber
Z calculated values
P
Difference
2.88 3.76 0.8 3.44 0.8 2.88 3.76
⬍.01 ⬍.01 ⬎.05 ⬍.01 ⬎01 ⬍.01 ⬍.01
Significant Significant Not significant Significant Not significant Significant Significant
1st day: ZOE and Kalzinol 2nd day: ZOE and Kalzinol 4th day: ZOE and Kalzinol ZOE: 1st and 2nd days ZOE: 2nd and 4th days Kalzinol: 1st and 2nd days Kalzinol: 2nd and 4th days
Table II. Leakage score at different intervals in both experimental groups Leakage score: zinc oxide eugenol
Leakage score: Kalzinol
Day
n
0
1
2
3
4
n
0
1
2
3
4
1st day 2nd day 4th day 7th day
10 10 10 10
0 0 0 0
0 0 0 0
7 0 0 0
3 2 0 0
0 8 10 10
10 10 10 10
0 0 0 0
6 0 0 0
4 7 0 0
0 3 2 0
0 0 8 10
extent of leakage was scored according to the criteria shown in Table I. The data were analyzed using the MannWhitney U-test to determine whether there was any statistically significant difference between the pairs of groups. RESULTS Results of this study demonstrated variable leakage patterns in both groups at all intervals. These results are summarized in Table II. There was a statistically significant difference in dye leakage between ZOE and Kalzinol on the first and second days, with Kalzinol showing better sealability, whereas on the fourth day no significant difference was found between the two groups. On the seventh day, both ZOE and Kalzinol exhibited complete dye penetration into the pulp chamber in all the samples. Microleakage observed in ZOE was significantly more on the second day than on the first day, whereas on the fourth day, no significant difference from the second day was observed. With Kalzinol, the severity of the leakage increased from the first day onward, with statistically significant differences in dye penetration between the first and second days and the second and fourth days. DISCUSSION For evaluation of microleakage, the methylene blue dye penetration method was used in this study because it is a simple and inexpensive technique and has displayed better penetration results than eosin14 or the radioisotope tracers 45 Ca-labeled calcium chloride, 14C-labeled urea, and 125Ilabeled albumin.15,16 The results of this study indicated that penetration of dye into the pulp chamber was prevented by ZOE and reinforced
ZOE restoration of endodontic access preparations only up to the first day and the third day, respectively. Whereas there have been no published reports suggesting the time up to which these restorations prevented microleakage, many previous studies have demonstrated extensive leakage in ZOE preparations during 3- to 7-day testing periods.8-15 These observations, however, do not concur with the report of Guerra et al,5 who found no leakage to minimal leakage in 2- to 4-mm-thick ZOE bases over gutta-percha obturation up to 1 week. Bergenholtz et al6 and Brannstrom,7 while evaluating bacterial leakage around restorations, demonstrated a bacteria-tight seal in ZOE restorations. Brannstrom,7 in his extensive work, even recommended sealing ZOE cement over other restorative materials to provide a bacteria-tight seal for evaluation of pulp response in experimental studies. The findings of the present study suggest that the bacteria-tight seal provided by ZOE cement may not be a result of its sealing properties but simply of its antimicrobial effect. ZOE cement seals the cavity well against the ingress of oral fluids, at least for a short time, mainly because of its better adaptation to the cavity wall, its coefficient of thermal expansion similar to the tooth, and its hygroscopic and antimicrobial properties.17,18 The extensive leakage in this study, from the second day onward in ZOE and from the fourth day onward in Kalzinol, could be attributed to dissolution or disintegration of ZOE because of moisture contact. Set ZOE cement consists of zinc oxide powder bonded together with a loose matrix of zinc eugenolate. This reaction is reversible, and zinc eugenolate is easily hydrolyzed by moisture to eugenol and zinc hydroxide.18 The better sealing ability displayed by reinforced
718 Tewari and Tewari
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY June 2002
Fig 1. Photograph showing grade-1 leakage reaching up to onethird of cavity wall in Kalzinol restoration on the first day.
Fig 3. Photograph showing grade-4 leakage reaching the pulp chamber in ZOE cement restoration on the second day.
Fig 2. Tooth section showing grade-3 leakage staining more than two-thirds of wall in ZOE cement restoration on the first day.
Fig 4. Photograph showing grade-4 leakage reaching the pulp chamber in Kalzinol restoration on the fourth day.
ZOE cement is in accordance with the previous study of Jenderson and Phillips19 and could be related to its better resistance to dissolution. In Kalzinol, reinforcement of ZOE with polystyrene polymer significantly improves its
abrasion resistance and compressive strength and decreases dissolution.19 In order to correlate the results to clinical use, thermocycling was not performed in this study. Jacquot et al13
Tewari and Tewari 719
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 93, Number 6
cautioned against the use of thermocycling for in vitro dye evaluation, because thermocycling damages ZOE preparations more than other materials. Tamse et al14 reported severe leakage in 3 days in 8 out of 10 samples with Kalzinol restorations, and Kazemi et al15 demonstrated mean dye penetration of 4.87 mm in just 24 hours in 5-mm bulk IRM restorations when subjected to thermocycling. In this study, the thickness of the ZOE restorations was at least 4 mm, complying with the recommendation of Webber et al.20 However, the P/L ratio was 6:1, to form a thick putty-like consistency. The thinner mixes (2:1 P/L ratio), which display the best seal as reported by Pashley et al,12 were not found adequate to seal access cavities. They were readily washed out under clinical conditions because of their prolonged setting time and inferior physical properties. This 2:1 P/L ratio is used in ZOE endodontic sealers and may be the reason why ZOE sealers perform well both in clinical and in-vitro studies. Within the limits of this study, we conclude that ZOE cement does not provide even a short-term adequate coronal seal in endodontic access cavities. The findings of this study demonstrate extensive dye penetration in 4- to 5-mm bulk ZOE restoration after just 1 day for ZOE and 3 days for Kalzinol. This suggests that further evaluation of the sealing properties of these cements is needed in order to verify whether the clinical success of ZOE is the result of its sealing properties or antibacterial properties.21 REFERENCES 1. Grossman LI. A study of temporary fillings as hermetic sealing agents. J Dent Res 1939;18:67-71. 2. Weine FS. Endodontic therapy. 4th ed. St. Louis: CV Mosby; 1989. p. 354-8. 3. Parris L. Kapsimalis P. The effect of temperature change on the sealing properties of temporary filling materials. Oral Surg Oral Med Oral Pathol 1960;13:982-9. 4. McInerney ST, Zillich R. Evaluation of internal sealing ability of three materials. J Endod 1992;18:376-8. 5. Guerra JA, Skribner JE., Lin LM. Influence of a base on coronal microleakage of post prepared teeth. J Endod 1994;20:589-91.
6. Bergenholtz G, Joesche WJ, Syed SA. Bacterial leakage around dental restorations: its effect on the dental pulp. J Oral Pathol 1982;11:439-50. 7. Brannstrom M. Dentin and pulp in restorative dentistry. London: Wolfe Medical Publication Ltd; 1982. p. 87-90. 8. Bobotis HG, Anderson RW, Pashley DH, Pantera EA. A microleakage study as temporary restorative materials used in endodontics. J Endod 1989;15:569-72. 9. Barkhordar RA, Stark MM. Sealing ability of intermediate restorations and cavity design used in endodontics. Oral Surg Oral Med Oral Pathol 1990;69:99-101. 10. Lee YC, Yang SF, Hwang YF, Chueh LH, Chung KH. Microleakage of endodontic temporary restorative materials. J Endod 1993;19:516-20. 11. Anderson RW, Powel BJ, Pashley DH. Microleakage of three temporary endodontic restorations. J Endod 1988;14:497-501. 12. Pashley EL, Tao L, Pashley DH. The sealing properties of temporary filling materials. J Prosthet Dent 1988;60:292-7. 13. Jacquot BM, Panghi MM, Steinmetz P, G’Sell C. Microleakage of Cavit, Cavit W, Cavit G, and IRM by impedance spectroscopy. Int Endod J 1996;29:256-61. 14. Tamse A, Ben-Amer A, Gover A. Sealing properties of temporary filling materials used in endodontics. J Endod 1982;8: 322-5. 15. Kazemi RB, Safavi KE, Spanberg LSW. Assessment of marginal sealability and permeability of an interim restorative endodontic material. Oral Surg Oral Med Oral Pathol 1994;78:788-96. 16. Matloff IR, Jensen JR, Singar L, Tabibi A. A comparison of methods used in root canal sealability studies. Oral Surg Oral Med Oral Pathol 1982;53:203-8. 17. Phillips RW. Skinners science of dental materials. 8th ed. Philadelphia: WB Saunders Co; 1982. p. 318-9. 18. Hume WR. The pharmacologic and toxicological properties of zinc oxide eugenol. J Am Dent Assoc 1986;113:789-91. 19. Jenderson M, Phillips RW, Swartz ML. A comparative study of four zinc oxide eugenol formulations as restorative material. J Prosthet Dent 1969;21:176-83. 20. Webber RT, del Rio CE, Brady JM, Segall RO. Sealing quality of a temporary filling material. Oral Surg Oral Med Oral Pathol 1978;46:123-30. 21. Chohayeb AD, Bassiouny MA. Sealing ability of intermediate restorative used in endodontics J Endod 1985;11:241-4. Reprint requests: Sanjay Tewari, MDS 6/6J Medical Enclave Pt.B.D.Sharma P.G.I.M.S. Rohtak 124001 Haryana India [email protected]
AVAILABILITY OF JOURNAL BACK ISSUES As a service to our subscribers, copies of back issues of Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics for the preceding 5 years are maintained and are available for purchase from the publisher, Mosby, until inventory is depleted. The following quantity discounts are available: 25% off on quantities of 12 to 23; one third off on quantities of 24 or more. Please write to Mosby, Subscription Customer Service, 6277 Sea Harbor Dr, Orlando, FL 32887, or call 800-654-2452 or 407-345-4000 for information on availability of particular issues and prices. If unavailable from the publisher, photocopies of complete issues are available from Bell & Howell Information and Learning, 300 N Zeeb Rd, Ann Arbor, MI 48106-1346; (734) 761-4700 or (800) 521-0600.