Evaluation of the sealant in orthodontic bonding Wei Nan Wang, BDS,* and Tien Hsiang Tarng, BDS, MS** Taipei, T a i w a n , R e p u b l i c o f China
In the two-paste self-polymerizing orthodontic bonding systems, sealants are routinely used to protect enamel, to decrease marginal leakage, to enhance bond strength, and to increase interfacial permeability for the etched enamel, the bonding resin, and the bracket base. However, some studies have questioned the need for the sealant. Bond strengths with and without sealants in orthodontic bonding were compared in this study. The results indicated no statistical differences between the tensile bond strengths of the two evaluated groups. The distributions of debonding interface between groups were similar and also had no statistical difference. This study therefore indicated that use of the sealant in the two-paste orthodontic bonding system for enhanced strength is unnecessary. However, the use of a sealant may offer extra protection to the enamel during debonding procedures. (AM J ORTHODDENTOFACORTHOP1991 ;100:209-11 .)
A c c o r d i n g to previous reports in the literature, the purposes for the use of a resin sealant in the self-polymerizing two-paste orthodontic bonding system are to protect the enamel from consequent demineralization by the acid-etching procedures, J,2 to reduce p i t and fissure caries, 3-7 to enhance bond strength, "~° to increase the etched enamel retention, H to reduce marginal leakage, ~2"16 and to increase the interfacial permeability for the bracket and etched enamel. ~.j7 Conversely, studies also show that sealants reduce bond strength, t8'~9 increase marginal leakage, 2° and cause white-spot decalcification as a result of low abrasion. 21-24 Some reports show that sealants do not affect bond strength, H'~8'25-29 etched enamel retention, tt,18,~5-29 sealant penetration, 2935 and marginal microleakage. 19.21.~2Also, since sealants of the BIS-GMA type of self-polymerizing resin cannot be cured in a continuous thin layer, 36'37the limited curing of the sealant can cause weakness of the adhesive 37'38 and increased marginal leakage2 9 If the viscosity and thickness of the sealant are high, it enhances weakness of the adhesive 3°,3~,38 and also decreases the penetration of the resin into the etched enamel. 23,38 According to previous studies, the use of the sealant in self-polymerizing resin is questionable for the clinician. The specific aim of this study was to determine (1) Whether the sealant is indispensable in the two-paste system of orthodontic bonding, and (2) whether it affects the bond strength or debonding interface distribution. From the School of Dentistry, National Defense Medical Center. *Head, Orthodontic Section, Dental Department, Tri-Service General Hospital; director, Orthodontic Research Laboratory. **Resident, Orthodontic Section, Dental Department, Tri-Service Genera/Hospital; assistant, Orthodontic Research Laboratory. 8/1/23648
Table I, The bond strength between sealant and nonsealant groups ( k g / m m 2) '~
Group
............ Mean
Sealant Nonsealant
0.71 0.69
....
SD*
0.14 0. I 1
*SD = Standard deviation. p > 0.05.
MATERIALS AND METHODS The sample consisted of 50 permanent premolars extracted from young patients (9 to 16 years of age) in conjunction with orthodontic treatment and randomly divided into two groups of 25 teeth each. Dyna-Lock premolar brackets (Unitek Corp., Monrovia, Calif. ) and Concise (3M Corp., St. Paul, Minn.), a two-paste type of self-polymerizing resin, were selected for bonding. A 37% phosphoric acid solution (Concise) was used to etch the buccal surface of the enamel for 15 seconds. After etching, the teeth were rinsed with copious water lavage. The teeth in one group were coated with the sealant, whereas those in the other group were not. The two-paste composite resin of Concise was mixed homogenously and immediately applied to the bracket base, and the bracket was accurately pressed to the demarcated etched buccal enamel (standardized resin area). The excessive composite resin was removed with a dental probe from the bracket margin while the resin was beginning polymerization. The prepared teeth were then placed in a 37° C water bath for 24 hours before the tensile bond strength was tested. Tensile bond strength was recorded with an Instron universal machine (Instron Corp., Model 1000, Boston, Mass.). The bondfailure interfaces of the bracket bases and the enamel surfaces in each respective group were examined with the scanning electron microscope (Canscan Corporation, Serial 4, Cambridge, England). The bond-failure interfaces with mapping of energy-dispersive x-ray spectrometry (Philips Corporation,
209
2"10 Wang and Tarng
Am. J. Orthod. Dentofae. Orthop.
SeptemberI991
Table II. Distributive percentage of debonding interface between sealant and nonsealant groups (percent)
Group Sealant Nonsealant
Metal-resin Mean [ SO* ] Range 43 41
11.2 10.7
10-50 10-60
Withinresin Resin-enamel Enameldetached Mean I SD I Range Mean ] SD ] Range Mean I SD [ Range 25.0 22.0
7.5 6.4
15-30 10-50
32.0 33.0
11,0 13,8
20-60 5-50
0 4
0 4,0
0 0-20
*SD = Standard deviation. p > 0.05.
SW 9100, Hillegom, Holland), were analyzed. All the data were recorded and statistically analyzed, their means and standard deviations were determined and compared by oneway analysis of variance, and the means were ranked by a t test calculated at a 95% level of confidence. 4° All detailed procedures and calculations of the percentages of broken interfaces have been described in previous reports. 4~,44
RESULTS The mean of the bond strength in the sealant group was 0.71 k g / m m z, whereas in the nonsealant group it was 0.69 k g / m m 2. The t test at a 95% level of confidence was not statistically significant, as shown in Table I. In the broken-interface analysis, four types Of debonding interfaces were found: (1) interface failure between resin and bracket base, (2) cohesive failure of resin itself, (3) interface failure between resin and enamel, and (4) surface enamel detachment. The distributive percentages of the various bondfailure interfaces are shown in Table II. For the group with the sealant, 43% bond failure occurred in the bracket-resin interface, 25% within the resin itself, and 32% i n the resin-enamel interface; there were no instances of surface enamel detachment. For the nonsealantgroup, 41% bond failure occurred in the bracketresin interface, 22% within the resin itself, and 33% in the resin-enamel interface; 4% showed surface enamel detachment. However, there are no statistically significant differences among the debonding interface percentages between the sealant and nonsealant groups.
DISCUSSION On the basis of the results of tensile bond strength tests, the differences between sealant and nonsealant groups were not statistically significant at the 95% level (Table I). Moreover, the distribution of the bond-failure interfaces was similar between these t w o groups (Table II). The results of this study are in agreement with those previously reported. ",m,zs'z9 Therefore it is suggested that the sealant may notbe necessary in two-paste orthodontic bonding.
The calculative method of determining the percentages of the debonding interface distribution and diagrams of each debonding interface have been described in detail in our previous studies.44'a5 AI! present data are validative. In the sealant group, no enamel detachment was found. In the nonsealant group, the composite resin bonded to the etched enamel directly and caused detachment of the etched enamel directly after debonding in 4% of the samples. Thus the use of a sealant may protect the etched enamel during debonding. The retention of resin is dependent on the wettabiiity of the resin and on the surface topography of the etched enamel. The use of a sealant may affect the bond strength 8"1°,18,t9 and the interfacial permeability between resin and etched enamel,~,t~' 17In this study, the findings showed that there were no obvious differences in bond strength and distribution of bond-failure interfaces between the two groups. The viscosity of sealants of the BIS-GMA type of self-polymerizing resin apparentIY Cannot be cured in a continuous thin a7 or thick 4' layer. Also affected are bond strength,3°'31~ 37'38 marginal microleakage,39 in terfacial permeability, 2~'~8 and accurate bracketing. "~ Therefore use of the sealant in self-polymerizing resins may be contraindicated. Furthermore, salivary calcium phosphate salts begin to be deposited onto the etched area almost immediately, and within 48 to 96 hours the etched enamel surface returns to normal. 42 Hence, the etched enamel may be rernineralized immediately if a layer of sealant is not applied before bonding.
CONCLUSION There were no significant differences in the tensile bond strength and the various debonding interfaces for the sealant and the nonsealant groups in the bonding of brackets. The results indicate that it is probablY not necessary to use sealant in the two-paste orthodontic bonding procedure. However, the use of a sealant may offer extra protection to enamel from possible damage during debonding. I would like to thank Dr. T.M. Graber and Dr. H.M. Tsai for their enthusiastic help.
Volume 100 Number 3
REFERENCES 1. Zachrisson BU. Iatrogenie damage in orthodontic treatment (JCO/Interviews). J Clin Orthod 1978;12:208-20. 2. Smith RA, Bellezza JJ, Capilouto ML, Bradley EL, Denys FR, Relief DH. A clinical study of the composite/bonding resintooth i'nterface. Dent Mater 1987;3:218-23. 3. Jensen OE, Handelman SL, Perez-Diez F. Occlusal wear of four pit and fissure sealants over two years. Pediatr Dent 1985;7: 23-9. 4. Mertz-Fairhurst EJ, Fairhurst CW, Williams JE, Della-Giustina VE, Brooks JD. A comparative clinical study of two pit and fissure sealants: 7-year results in Augusta, Ga. J Am Dent Assoc 1984;109:252-5. 5. Houpt M, Eidelman E, Shey Z, Fuks A, Chosack A, Shapira J. Occlusal restoration using fissure sealant instead of "extension for prevention." ASDC J Dent Child 1984;51:270-3. 6. Calderone JJ, Mueller LA. The cost of sealant application in a state dental disease prevention program. J Public Health Dent 1983;43:249-54. 7. Callanen VA, Weintraub JA, French DP, Connolly GN. Developing a sealant program: the Massachusetts approach. J Public Health Dent 1986;46:141-6. 8. Gwinnett AJ. State of the art and science of bonding in orthodontic treatment. Council on materials, instruments and equipment. J Am Dent Assoc 1982;105:844-50. 9. Roy M, King GE. Evaluation of primers used for bonding silicone to denture base material. J Prosthet Dent 1989;61:636-9. 10. Hormafi AA, Denehy GE, Fuller JL. Retentiveness of enamelresin bonds using unfilled and filled resins. J Prosthet Dent 1982;47:502-4. 11. Espinosa HD. In vitro study of resin-supported internally etched enamel. J Prosthet Dent 1978;40:526-30. 12. Dogon IL. Studies demonstrating the need for an intermediary resin of low viscosity for the acid etch technique. In: Silverstone LM, Dogon IL, eds. Proceedings of an international symposium on the acid etch technique. St. Paul, Minn.: North Central Publishing: 1975;100-18. 13. Kempler D, Stark MM, Leung RL, Greenspan JS. Enamel composite interface relative to cavosurface configuration, abrasion and bonding agents. Oper Dent 1976; 1:137-45. 14. Luescher B, Lutz F, Ochsenbein H, Muhlemann HR. Microleakage and marginal adaptation in conventional and adhesive Class II restorations. J Prosthet Dent 1977;37:300-9. 15. Forsten L. Marginal leakage and consistency of the composite resin material in etched cavities. Acta Odontol Scand 1978; 36:11-3. 16. Sparrius O, Grossman ES. Marginal leakage of composite resin restorations in combination with dentinal and enamel bonding agents. J Prosthet Dent 1989;61:678-84. 17. Baharav H, Cardash HS, Helft M, Langsam J. Penetration of etched enamel by bonding agents. J Prosthet Dent 1988;59: 33-6. 18. Mitchem JC, Turner LR. The retentive strength of acid-etched retained resins. J Am Dent Assoc 1974;89:1107-10. 19. Adipronto S, Beech DR, Hardwick JL. Effect of pretreatment of enamel on bonding to composite restorative materials. J Dent Res 1975;54:Abstr. L354. 20. Ortiz RF, Phillips RW, Swartz ML, Osborne JW. Effect of composite resin bond agent on microleakage and bond strength. J Prosthet Dent 1979;41:51-7. 21. Gorelick L, Geiger AM, Gwinnett AJ. Incidence of white spot lesions associated with bands and bonding. AM J ORTHOD 1982;81:93-8. 22. Ceen RF, Gwlnnett AJ. White spot formation associated with sealants and in orthodontics. Pediatr Dent 1981;3:174-8.
Sealant in orthodontic bonding
211
23. Phillips HW. Bonding. Part 1 and 2 (JCO/Interviews). J Clin Orthod 1980;14:391-411,462-80, 24. Ceen RF, Gwinnett AJ. Microscopic evaluation of the thickness of sealant used in orthdontic bonding. AM J ORTHOD 1980; 78:623-9. 25. LOWT, Lee KW, Von Frannhofer JA. The direct use of composite materials in adhesive dentistry. Br Dent J 1976;41:207-13. 26. Rider M, Tanner AN, Kenny B. Investigation of adhesive properties of dental composite materials using an improved tensile test procedure and scanning microscopy. J Dent Res 1977; 56:368-78. 27. Raadal M. Bond strength of composites applied to acid-etched enamel. Scant I Dent Res 1978;86:157-62, 28. Soetopo, Beech DR, Hardwick JL. Mechanism of adhesion of polymers to acid-etched enamel. J Oral Rehabil 1978;5:69-80. 29. Jorgensen KD, Shimokobe H. Adaptation of resinous restorative materials to acid etched enamel surfaces. Stand J Dent Res 1975;83:31-6. 30. Pahlavan A, Dennison JB, Charbeneau GT. Penetration of restorative resins into acid etched enamel. J Am Dent Assoc 1976;93:1170-6. 31. Asmussen E, Penetration of restorative resins into acid etched enamel. II. Dissolution of entrapped air in restorative resin monomers. Acta Odontol Stand 1977;35:183-9 I. 32. Barnes IE. The adaptation of composite resins to tooth structure. Br Dent J 1977;i42:185-91. 33. Low T, Lee KW, Von Fraunhofer JA. The adaptation of composite materials to etched enamel surfaces. J Oral Rehabii 1978;5:349-55. 34. Retief DH, Woods E,/amison HC. Effect of cavosuffaee treatment on marginal leakage in Class V composite resin restorations. J Prosthet Dent 1982;47:496-501. 35. Newman IG, Mevaste M. The intermediate effect of low viscous fissure sealants on the retention of resin restoratives in vitro. Proc Finn Dent Soc 1975;7i:96-101. 36. Draughn RA. The effect of thermal cycling on retention of composite restorativeS. J Dent Res 1976;55:Abstr. 303. 37. Ulbrieht L Inhibitors and inhibition constants in free radical polymerization. In: Brandrup J, Immergut EH, eds. Polymer handbook. 2nd ed, New York: John Wiley &Sons 1975;11-55. 38. Ten Care JM, Keizer S, Mends J. Polymer adhesion to enamel: the influence of viscosity and penetration. J Oral Rehabil 1977;4:149-56. 39, Retief DH, Woods E. Is a low viscosity bonding resin necessary? J Oral Rehabil 1981;8:255-66. 40. Steel RG, Torrie JH. Principles and procedures of statistics. 2nd ed. New York: McGraw-Hill 1980;60. 41, Zachrisson BU, Heimgard E, Ruytcr IE, Mjor IA. Problems with sealants for bracket bonding. AM J O~THOB 1979;75:641-9. 42. Snawder KD. Handbook ofelinical pedodontics. St. Louis, Mo.: CV Mosby 1980;111-6. 43. Wang WN. Tensile bond strength of orthodontic resins on the human tooth surface. Proc Natl Sci Counc Repub China [B], 1988;12:228-35. 44. Wang WN, Lu TC. Bond strength with various etching times on young permanent teeth. AM J ORTHOD DENTOFACORTHOP. [In press].
Reprint requests to: Dr. Wei Nan Wang Orthodontic Section Dental Department of Tri-Service General Hospital School of Dentistry National Defense Medical Center Taipei, Talwan, Republic of China 10713
In the two-paste self-polymerizing orthodontic bonding systems, sealants are routinely used to protect enamel, to decrease marginal leakage, to enhance bond strength, and to increase interfacial permeability for the etched enamel, the bonding resin, and the bracket base. However, some studies have questioned the need for the sealant. Bond strengths with and without sealants in orthodontic bonding were compared in this study. The results indicated no statistical differences between the tensile bond strengths of the two evaluated groups. The distributions of debonding interface between groups were similar and also had no statistical difference. This study therefore indicated that use of the sealant in the two-paste orthodontic bonding system for enhanced strength is unnecessary. However, the use of a sealant may offer extra protection to the enamel during debonding procedures. (AM J ORTHODDENTOFACORTHOP1991 ;100:209-11 .)
A c c o r d i n g to previous reports in the literature, the purposes for the use of a resin sealant in the self-polymerizing two-paste orthodontic bonding system are to protect the enamel from consequent demineralization by the acid-etching procedures, J,2 to reduce p i t and fissure caries, 3-7 to enhance bond strength, "~° to increase the etched enamel retention, H to reduce marginal leakage, ~2"16 and to increase the interfacial permeability for the bracket and etched enamel. ~.j7 Conversely, studies also show that sealants reduce bond strength, t8'~9 increase marginal leakage, 2° and cause white-spot decalcification as a result of low abrasion. 21-24 Some reports show that sealants do not affect bond strength, H'~8'25-29 etched enamel retention, tt,18,~5-29 sealant penetration, 2935 and marginal microleakage. 19.21.~2Also, since sealants of the BIS-GMA type of self-polymerizing resin cannot be cured in a continuous thin layer, 36'37the limited curing of the sealant can cause weakness of the adhesive 37'38 and increased marginal leakage2 9 If the viscosity and thickness of the sealant are high, it enhances weakness of the adhesive 3°,3~,38 and also decreases the penetration of the resin into the etched enamel. 23,38 According to previous studies, the use of the sealant in self-polymerizing resin is questionable for the clinician. The specific aim of this study was to determine (1) Whether the sealant is indispensable in the two-paste system of orthodontic bonding, and (2) whether it affects the bond strength or debonding interface distribution. From the School of Dentistry, National Defense Medical Center. *Head, Orthodontic Section, Dental Department, Tri-Service General Hospital; director, Orthodontic Research Laboratory. **Resident, Orthodontic Section, Dental Department, Tri-Service Genera/Hospital; assistant, Orthodontic Research Laboratory. 8/1/23648
Table I, The bond strength between sealant and nonsealant groups ( k g / m m 2) '~
Group
............ Mean
Sealant Nonsealant
0.71 0.69
....
SD*
0.14 0. I 1
*SD = Standard deviation. p > 0.05.
MATERIALS AND METHODS The sample consisted of 50 permanent premolars extracted from young patients (9 to 16 years of age) in conjunction with orthodontic treatment and randomly divided into two groups of 25 teeth each. Dyna-Lock premolar brackets (Unitek Corp., Monrovia, Calif. ) and Concise (3M Corp., St. Paul, Minn.), a two-paste type of self-polymerizing resin, were selected for bonding. A 37% phosphoric acid solution (Concise) was used to etch the buccal surface of the enamel for 15 seconds. After etching, the teeth were rinsed with copious water lavage. The teeth in one group were coated with the sealant, whereas those in the other group were not. The two-paste composite resin of Concise was mixed homogenously and immediately applied to the bracket base, and the bracket was accurately pressed to the demarcated etched buccal enamel (standardized resin area). The excessive composite resin was removed with a dental probe from the bracket margin while the resin was beginning polymerization. The prepared teeth were then placed in a 37° C water bath for 24 hours before the tensile bond strength was tested. Tensile bond strength was recorded with an Instron universal machine (Instron Corp., Model 1000, Boston, Mass.). The bondfailure interfaces of the bracket bases and the enamel surfaces in each respective group were examined with the scanning electron microscope (Canscan Corporation, Serial 4, Cambridge, England). The bond-failure interfaces with mapping of energy-dispersive x-ray spectrometry (Philips Corporation,
209
2"10 Wang and Tarng
Am. J. Orthod. Dentofae. Orthop.
SeptemberI991
Table II. Distributive percentage of debonding interface between sealant and nonsealant groups (percent)
Group Sealant Nonsealant
Metal-resin Mean [ SO* ] Range 43 41
11.2 10.7
10-50 10-60
Withinresin Resin-enamel Enameldetached Mean I SD I Range Mean ] SD ] Range Mean I SD [ Range 25.0 22.0
7.5 6.4
15-30 10-50
32.0 33.0
11,0 13,8
20-60 5-50
0 4
0 4,0
0 0-20
*SD = Standard deviation. p > 0.05.
SW 9100, Hillegom, Holland), were analyzed. All the data were recorded and statistically analyzed, their means and standard deviations were determined and compared by oneway analysis of variance, and the means were ranked by a t test calculated at a 95% level of confidence. 4° All detailed procedures and calculations of the percentages of broken interfaces have been described in previous reports. 4~,44
RESULTS The mean of the bond strength in the sealant group was 0.71 k g / m m z, whereas in the nonsealant group it was 0.69 k g / m m 2. The t test at a 95% level of confidence was not statistically significant, as shown in Table I. In the broken-interface analysis, four types Of debonding interfaces were found: (1) interface failure between resin and bracket base, (2) cohesive failure of resin itself, (3) interface failure between resin and enamel, and (4) surface enamel detachment. The distributive percentages of the various bondfailure interfaces are shown in Table II. For the group with the sealant, 43% bond failure occurred in the bracket-resin interface, 25% within the resin itself, and 32% i n the resin-enamel interface; there were no instances of surface enamel detachment. For the nonsealantgroup, 41% bond failure occurred in the bracketresin interface, 22% within the resin itself, and 33% in the resin-enamel interface; 4% showed surface enamel detachment. However, there are no statistically significant differences among the debonding interface percentages between the sealant and nonsealant groups.
DISCUSSION On the basis of the results of tensile bond strength tests, the differences between sealant and nonsealant groups were not statistically significant at the 95% level (Table I). Moreover, the distribution of the bond-failure interfaces was similar between these t w o groups (Table II). The results of this study are in agreement with those previously reported. ",m,zs'z9 Therefore it is suggested that the sealant may notbe necessary in two-paste orthodontic bonding.
The calculative method of determining the percentages of the debonding interface distribution and diagrams of each debonding interface have been described in detail in our previous studies.44'a5 AI! present data are validative. In the sealant group, no enamel detachment was found. In the nonsealant group, the composite resin bonded to the etched enamel directly and caused detachment of the etched enamel directly after debonding in 4% of the samples. Thus the use of a sealant may protect the etched enamel during debonding. The retention of resin is dependent on the wettabiiity of the resin and on the surface topography of the etched enamel. The use of a sealant may affect the bond strength 8"1°,18,t9 and the interfacial permeability between resin and etched enamel,~,t~' 17In this study, the findings showed that there were no obvious differences in bond strength and distribution of bond-failure interfaces between the two groups. The viscosity of sealants of the BIS-GMA type of self-polymerizing resin apparentIY Cannot be cured in a continuous thin a7 or thick 4' layer. Also affected are bond strength,3°'31~ 37'38 marginal microleakage,39 in terfacial permeability, 2~'~8 and accurate bracketing. "~ Therefore use of the sealant in self-polymerizing resins may be contraindicated. Furthermore, salivary calcium phosphate salts begin to be deposited onto the etched area almost immediately, and within 48 to 96 hours the etched enamel surface returns to normal. 42 Hence, the etched enamel may be rernineralized immediately if a layer of sealant is not applied before bonding.
CONCLUSION There were no significant differences in the tensile bond strength and the various debonding interfaces for the sealant and the nonsealant groups in the bonding of brackets. The results indicate that it is probablY not necessary to use sealant in the two-paste orthodontic bonding procedure. However, the use of a sealant may offer extra protection to enamel from possible damage during debonding. I would like to thank Dr. T.M. Graber and Dr. H.M. Tsai for their enthusiastic help.
Volume 100 Number 3
REFERENCES 1. Zachrisson BU. Iatrogenie damage in orthodontic treatment (JCO/Interviews). J Clin Orthod 1978;12:208-20. 2. Smith RA, Bellezza JJ, Capilouto ML, Bradley EL, Denys FR, Relief DH. A clinical study of the composite/bonding resintooth i'nterface. Dent Mater 1987;3:218-23. 3. Jensen OE, Handelman SL, Perez-Diez F. Occlusal wear of four pit and fissure sealants over two years. Pediatr Dent 1985;7: 23-9. 4. Mertz-Fairhurst EJ, Fairhurst CW, Williams JE, Della-Giustina VE, Brooks JD. A comparative clinical study of two pit and fissure sealants: 7-year results in Augusta, Ga. J Am Dent Assoc 1984;109:252-5. 5. Houpt M, Eidelman E, Shey Z, Fuks A, Chosack A, Shapira J. Occlusal restoration using fissure sealant instead of "extension for prevention." ASDC J Dent Child 1984;51:270-3. 6. Calderone JJ, Mueller LA. The cost of sealant application in a state dental disease prevention program. J Public Health Dent 1983;43:249-54. 7. Callanen VA, Weintraub JA, French DP, Connolly GN. Developing a sealant program: the Massachusetts approach. J Public Health Dent 1986;46:141-6. 8. Gwinnett AJ. State of the art and science of bonding in orthodontic treatment. Council on materials, instruments and equipment. J Am Dent Assoc 1982;105:844-50. 9. Roy M, King GE. Evaluation of primers used for bonding silicone to denture base material. J Prosthet Dent 1989;61:636-9. 10. Hormafi AA, Denehy GE, Fuller JL. Retentiveness of enamelresin bonds using unfilled and filled resins. J Prosthet Dent 1982;47:502-4. 11. Espinosa HD. In vitro study of resin-supported internally etched enamel. J Prosthet Dent 1978;40:526-30. 12. Dogon IL. Studies demonstrating the need for an intermediary resin of low viscosity for the acid etch technique. In: Silverstone LM, Dogon IL, eds. Proceedings of an international symposium on the acid etch technique. St. Paul, Minn.: North Central Publishing: 1975;100-18. 13. Kempler D, Stark MM, Leung RL, Greenspan JS. Enamel composite interface relative to cavosurface configuration, abrasion and bonding agents. Oper Dent 1976; 1:137-45. 14. Luescher B, Lutz F, Ochsenbein H, Muhlemann HR. Microleakage and marginal adaptation in conventional and adhesive Class II restorations. J Prosthet Dent 1977;37:300-9. 15. Forsten L. Marginal leakage and consistency of the composite resin material in etched cavities. Acta Odontol Scand 1978; 36:11-3. 16. Sparrius O, Grossman ES. Marginal leakage of composite resin restorations in combination with dentinal and enamel bonding agents. J Prosthet Dent 1989;61:678-84. 17. Baharav H, Cardash HS, Helft M, Langsam J. Penetration of etched enamel by bonding agents. J Prosthet Dent 1988;59: 33-6. 18. Mitchem JC, Turner LR. The retentive strength of acid-etched retained resins. J Am Dent Assoc 1974;89:1107-10. 19. Adipronto S, Beech DR, Hardwick JL. Effect of pretreatment of enamel on bonding to composite restorative materials. J Dent Res 1975;54:Abstr. L354. 20. Ortiz RF, Phillips RW, Swartz ML, Osborne JW. Effect of composite resin bond agent on microleakage and bond strength. J Prosthet Dent 1979;41:51-7. 21. Gorelick L, Geiger AM, Gwinnett AJ. Incidence of white spot lesions associated with bands and bonding. AM J ORTHOD 1982;81:93-8. 22. Ceen RF, Gwlnnett AJ. White spot formation associated with sealants and in orthodontics. Pediatr Dent 1981;3:174-8.
Sealant in orthodontic bonding
211
23. Phillips HW. Bonding. Part 1 and 2 (JCO/Interviews). J Clin Orthod 1980;14:391-411,462-80, 24. Ceen RF, Gwinnett AJ. Microscopic evaluation of the thickness of sealant used in orthdontic bonding. AM J ORTHOD 1980; 78:623-9. 25. LOWT, Lee KW, Von Frannhofer JA. The direct use of composite materials in adhesive dentistry. Br Dent J 1976;41:207-13. 26. Rider M, Tanner AN, Kenny B. Investigation of adhesive properties of dental composite materials using an improved tensile test procedure and scanning microscopy. J Dent Res 1977; 56:368-78. 27. Raadal M. Bond strength of composites applied to acid-etched enamel. Scant I Dent Res 1978;86:157-62, 28. Soetopo, Beech DR, Hardwick JL. Mechanism of adhesion of polymers to acid-etched enamel. J Oral Rehabil 1978;5:69-80. 29. Jorgensen KD, Shimokobe H. Adaptation of resinous restorative materials to acid etched enamel surfaces. Stand J Dent Res 1975;83:31-6. 30. Pahlavan A, Dennison JB, Charbeneau GT. Penetration of restorative resins into acid etched enamel. J Am Dent Assoc 1976;93:1170-6. 31. Asmussen E, Penetration of restorative resins into acid etched enamel. II. Dissolution of entrapped air in restorative resin monomers. Acta Odontol Stand 1977;35:183-9 I. 32. Barnes IE. The adaptation of composite resins to tooth structure. Br Dent J 1977;i42:185-91. 33. Low T, Lee KW, Von Fraunhofer JA. The adaptation of composite materials to etched enamel surfaces. J Oral Rehabii 1978;5:349-55. 34. Retief DH, Woods E,/amison HC. Effect of cavosuffaee treatment on marginal leakage in Class V composite resin restorations. J Prosthet Dent 1982;47:496-501. 35. Newman IG, Mevaste M. The intermediate effect of low viscous fissure sealants on the retention of resin restoratives in vitro. Proc Finn Dent Soc 1975;7i:96-101. 36. Draughn RA. The effect of thermal cycling on retention of composite restorativeS. J Dent Res 1976;55:Abstr. 303. 37. Ulbrieht L Inhibitors and inhibition constants in free radical polymerization. In: Brandrup J, Immergut EH, eds. Polymer handbook. 2nd ed, New York: John Wiley &Sons 1975;11-55. 38. Ten Care JM, Keizer S, Mends J. Polymer adhesion to enamel: the influence of viscosity and penetration. J Oral Rehabil 1977;4:149-56. 39, Retief DH, Woods E. Is a low viscosity bonding resin necessary? J Oral Rehabil 1981;8:255-66. 40. Steel RG, Torrie JH. Principles and procedures of statistics. 2nd ed. New York: McGraw-Hill 1980;60. 41, Zachrisson BU, Heimgard E, Ruytcr IE, Mjor IA. Problems with sealants for bracket bonding. AM J O~THOB 1979;75:641-9. 42. Snawder KD. Handbook ofelinical pedodontics. St. Louis, Mo.: CV Mosby 1980;111-6. 43. Wang WN. Tensile bond strength of orthodontic resins on the human tooth surface. Proc Natl Sci Counc Repub China [B], 1988;12:228-35. 44. Wang WN, Lu TC. Bond strength with various etching times on young permanent teeth. AM J ORTHOD DENTOFACORTHOP. [In press].
Reprint requests to: Dr. Wei Nan Wang Orthodontic Section Dental Department of Tri-Service General Hospital School of Dentistry National Defense Medical Center Taipei, Talwan, Republic of China 10713
