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post and core post and core Document Transcript

  • VOLUME 43 1 2012 e1 QUINTESSENCE INTERNATIONAL function.1,2 Fiber posts that are used after endodontic treatment have some addition- al advantages, including biocompatibility, mechanical strength, resistance to corro- sion, improvement of light transmission, and the optical effects of esthetic restorations.3 An important characteristic of fiber posts is a modulus of elasticity similar to dentin, resin cement, and resin core materials4 so that the occlusal loads can be better distributed along the root.5 In addition, the restoration of endodontically treated teeth with metal-free materials eliminates the potential hazards of corrosion and aller- gic hypersensitivity.6 Fiber-reinforced posts also have the advantage of easy removal if with prefabricated fiber post-and-core sys- tems has been widely accepted as a treat- ment option that offers both esthetics and 1 Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey. 2 Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey. 3 Research Assistant, Department of Prosthodontics, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey. 4 Private Practice, Ankara, Turkey. 5Professor, Department of Prosthodontics, Faculty of Dentistry, Selçuk University, Konya, Turkey. Correspondence: Dr Ahmet Umut Güler, Ondokuz Mayıs University, Faculty of Dentistry, Department of Prosthodontics 55139, Kurupelit, Samsun, Turkey. Email: auguler@omu.edu.tr Effects of different acids and etching times on the bond strength of glass fiber–reinforced composite root canal posts to composite core material Ahmet Umut Güler, DDS, PhD1 /Murat Kurt, DDS, PhD2 /Ibrahim Duran, DDS3 / Altay Uludamar, DDS, MSc, PhD4 /Ozgur Inan, DDS, PhD5 Objective: To investigate the effects of different acids and etching times on the bond Method and Materials: in the other groups were acid etched with 35% phosphoric acid and 5% and 9.6% hydro- polytetrafluoroethylene mold was placed around the treated posts and filled with dual-cure After 24 hours of water storage, the specimens were sectioned perpendicularly to the bonded interface under water cooling to obtain 2-mm post-and-core specimens. Eight specimens were made from each group. Push-out tests were performed at a crosshead speed of 0.5 mm/min using a universal testing machine. Data were analyzed by one-way α Results: The P the highest bond strength values (P Conclusion: - ing procedures tested showed significantly increased bond strength when compared with the control group. Acid-etching with 5% hydrofluoric acid and 9.6% hydrofluoric acid for 2 minutes and with 35% phosphoric acid for 3 minutes (groups H5-120, H9-120, and P-180, composite core material. Although the bond strength was increased by prolonged acid (Quintessence Int 2012;43:e1–e8 Key words: acid etching, bond strength, composite core material, etching time, © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
  • e2 VOLUME 43 1 2012 QUINTESSENCE INTERNATIONAL Güler et al endodontic retreatment is required. These systems can reduce the incidence of nonre- trievable root fractures when compared with prefabricated metallic posts or conventional cast posts.9,10 If the bonding of the interface is poor, debonding and/or fracturing of the core and post can occur.11 A good adaptation and reliable bonding between the post surface and core buildup material must be achieved.12 - cal studies of fiber-based post systems that present clinical failure rate. Glazer13 pub- lished results of a study in which the results for 52 teeth in 42 patients were analyzed. - cal pathology, while an additional two were mechanical failures of the restoration. A published prospective investigation14 dem- onstrated a failure rate of glass fiber posts of 12.8% after 24 months. The most frequent types of failure were post fractures or loss of retention. A retrospective study evaluat- ing 1,304 teeth restored with three different types of fiber posts from 1 to 6 years without recording the loss of coronal tooth structure reported a failure rate of 3.2%.15 smooth surface that limits mechanical inter- is often recorded at the post-composite guarantee a strong and durable fiber post- to-composite bond.16 Therefore, several methods for conditioning the post surface were investigated, including infiltration of bonding, silanization followed by bonding of the post surface,11,18–21 airborne-particle abrasion with corundum,20–23 tribochemi- 5,23 acid etching using 5% hydrofluoric acid followed by silani- zation,5,23,24 and surface activation using acetone, chloroform, hydrogen peroxide, or hydrochloric acid followed by silanization.24 These treatments result in surface micro- between the two surfaces and/or exposure of the fiber by removal of the matrix, per- mitting silanization with a silane coupling agent. Some of these treatments may cause detrimental effects when the treatment is performed over a long period of time, such as etching with hydrofluoric acid or blasting with aluminum oxide particles.25 Mechanical pretreatment of the glass fiber–reinforced only is the matrix removed, but the fibers might also be damaged, depending on the particle size and abrasion time.26 To optimize the bonding of resin cements the posts have been proposed, such as etching with phosphoric or hydrofluoric acid. The effect of etching varied depend- ing on the acid-etching time and acid type. The aim of this study was to investigate the effects of different acids and etching times on the bond strength of glass fiber– reinforced composite root canal posts to composite core material. It was hypoth- esized that the bond strength achieved at the post-core interface was affected by the various acids and acid-etching times. METHOD AND MATERIALS Twenty-six fiber-reinforced composite root being a control group that received no The specimens in group P-30 were acid etched with 35% phosphoric acid gel (Ultra- 30 seconds, the specimens in group P-60 were acid etched for 60 seconds, the speci- mens in group P-120 were acid etched for 2 minutes, and the specimens in group P-180 were acid etched for 3 minutes. After the acid-etching procedures, all specimens were rinsed with water for 30 seconds and dried with oil-free air spray for 30 seconds. The specimens in group H5-30 were acid etched with 5% hydrofluoric acid gel - mens in group H5-60 were acid etched for 60 seconds, the specimens in group H5-120 were acid etched for 2 minutes, and the specimens in group H5-180 were acid © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
  • VOLUME 43 1 2012 e3 QUINTESSENCE INTERNATIONAL Güler et al etched for 3 minutes. After the acid-etching procedures, all specimens were rinsed with water for 30 seconds and dried with oil-free air spray for 30 seconds. The specimens in group H9-30 were acid etched with 9.6% hydrofluoric acid in group H9-60 were acid etched for 60 seconds, the specimens in group H9-120 were acid etched for 2 minutes, and the specimens in group H9-180 were acid etched for 3 minutes. After the acid-etching procedures, all specimens were rinsed with water for 30 seconds and dried with oil-free air spray for 30 seconds. - allel in the coronal and tapered in the apical part of its design. A polytetrafluoroethylene tapered part of the posts. The tapered sec- tion was placed in the PTFE mold, while the parallel section was used for the core foundation to simplify the calculation of the surface area. Only the upper cylindric the larger diameter of 2 mm was used. It is ideal for the post diameter to be constant throughout the post length. A cylindric PTFE mold was placed around the coronal part of Photoactivation was performed by using a light-emitting diode unit with 1,550 mW/ cm2 The tip of the light unit was initially placed at the top of the PTFE mold for 20 seconds and then through the mold on each side for 20 seconds, for a total exposure of 60 sec- - tilled water, the specimens were attached to the arm of a low-speed saw (IsoMet, the bonded interface into 2-mm post-and- core segments under water cooling. Four segments were obtained from each post- and-core specimen—each group of eight post-and-core specimens provided a total of 104 post-and-core segments. The exact was measured using a digital micrometer was calculated using the formula: A = 2r × ∏ × h where r is the post radius, ∏ is the constant 3.14, and h coronal sections were used for core foun- dations, the bonding area was equal for all post segments and calculated as 2 × 3.14 × 1 × 2 = 12.56 mm2 . Push-out tests were performed at a crosshead speed of 0.5 mm/min using a loaded with a 1.5-mm–diameter cylindric stainless steel plunger. The tip of the equip- ment was positioned to contact only the of extrusion of the post segment from the Push-out bond strength values in MPa were then calculated by dividing this force by the bonded area of the post segment. using statistical software (SPSS for Windows effect of acid-etching procedures on bond core material. The means were then com- - α each group was prepared and evaluated by observed for surface irregularity under a scanning electron microscope at 250× and 500× magnification. Tip of apparatus FRC Postec Plus MultiCore Flow Fixation apparatus of sample Space for displaced filling material F Fig 1 Schematic drawing of push-out test of the specimens. © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
  • e4 VOLUME 43 1 2012 QUINTESSENCE INTERNATIONAL Güler et al RESULTS The bond strengths were shown to be sig- P < standard deviations, and group differences for the 13 groups are shown in Table 2. In the study groups, the lowest bond Group P-30 demonstrated a high- P - cant difference was observed among group P groups demonstrated higher bond strength values when compared with group P-30 - ference was observed among group H5-60 P groups demonstrated higher bond strength values when compared with the above mentioned groups (P significant difference was observed among (P the highest bond strength values in this study. The differences among all groups are listed in Table 2. The SEM studies revealed that the surface irregularities of the glass fiber– reinforced composite root canal post corre- sponded to the results of the bond strength DISCUSSION Within the limitations of the present study, it can be concluded that our hypothesis was confirmed—that the bond strengths of significantly affected by the investigated acid-etching procedures. Flowable and hybrid composites have been reported to have good adaptation at - ical properties of flowable composites are generally inferior to those of conventional composites. Therefore, a dual-cure com- also recommended as an adhesive luting agent and core buildup material was used in the present study. Table 1 One-way ANOVA table for study groups Variable (source) df Sum of squares Mean squares F P 12 88.036 .001* Within groups 91 51.405 0.565 Total 103 df, degrees of freedom. *Significant difference at P < .05. Table 2 Mean bond strengths (MPa), standard deviation (SD) values, and group differences for the study groups (each n = 8) Group Mean (MPa) SD Difference* 12.51 a P-30 13.85 .95 b H5-30 15.38 .99 c H9-30 15.64 .88 c P-60 c P-120 16.14 .43 c H5-60 .83 d H9-60 .59 d H5-180 .64 d H9-180 18.10 .53 d H5-120 20.31 .66 e H9-120 20.55 .54 e P-180 .94 e *Different letters indicate dissimilarity of groups (P © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
  • VOLUME 43 1 2012 e5 QUINTESSENCE INTERNATIONAL Güler et al A number of studies focused particularly on the possibility to improve adhesion at the fiber post–composite interface through vari- ous treatments of the post surface.1,6,28–30 Mechanical and chemical treatments of the post surfaces and changes in the post matrix composition seemed to affect the bond strength of resin materials to been evaluated to dissolve the epoxy resin matrix or methacrylate-based resin matrix and expose fibers and filler particles so that silanization could be effective. Use of hydrogen peroxide24 and differ- ent chemical agents (followed by silaniza- resin core materials with dissolving of the resin matrix of the post’s surface and con- comitant exposure of undamaged fibers.31 The use of hydrofluoric acid and tribo- chemical coating followed by silanization resulted in damaged fibers at the surface of 24,32 Different concentrations and etching times of acid agents were used in the studies investigating the effect of surface with hydrofluoric acid5,24,33,34 and phosphor- ic acid5,35 since clear information regarding the most appropriate etching conditions is In the present study, 35% phosphoric acid and 5% and 9.6% hydrofluoric acid Fig 2 (right) SEM images of untreat- ed specimen (control) at 250× magni- fication. The undamaged glass fibers and resin matrix around the fibers can be seen (a, glass fiber; b, resin matrix). Fig 3 (below) SEM images of treated specimens at 500× magnification. The cracks and damages on the glass fibers and dissolved resin matrix around the remaining fibers due to the different acid treatments can be seen. © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
  • e6 VOLUME 43 1 2012 QUINTESSENCE INTERNATIONAL Güler et al gel with four different etching times (30, evaluate time and concentration effects on the bond strength of glass fiber–reinforced composite root canal posts to composite core material. Even though there is no sta- tistical significance between 5% and 9.6% hydrofluoric acid treatments for all etching times, the hydrofluoric acid groups showed greater bond strength values than phos- phoric acid groups with the exception of the 180-second etching time. According to the images obtained with SEM, the post surface etched with phosphoric acid was not modi- epoxy matrix and fibers was observed on the surfaces etched with hydrofluoric acid This is a minority finding: The study indicated that conditioning with hydroflu- oric acid seemed to be very aggressive 5 Acid- etching treatment resulted in roughness of the post surface, which might have the luting cement and post surfaces. The authors attributed the roughness to frac- tured glass fibers and partial removal of the epoxy matrix.35 The bond strength values of the phos- phoric acid groups increased with longer etching times. This was also similar for the 30- and 60-second etching hydroflu- oric acid groups. Hydrofluoric acid–treated groups for 120 seconds showed higher bond strength values than those of groups treated for 180 seconds. Schmage et al stated that previously performed pretests with 120-second hydro- fluoric acid etching had shown that the described effect of increased surface tex- ture could be observed with increased etching time.36 However, any conditioning method including prolonged acid etch- ing would reduce the post diameter and cause misfitting posts with a wider cement gap, resulting in lower retentive bond strengths.26,36 while other chemical conditioning methods affect only the glass fibers.18 This is due to the corrosive effect of hydrofluoric acid on the glass phase of a ceramic matrix. These findings were confirmed when hydrofluoric acid was used for conditioning methacry- late-based fiber posts. Despite the improve- ment in post-to-composite bond strength, a noteworthy surface alteration ranging from fiber layer was detected.16,24 Although the bond strength was increased with longer etching times, the microstructure thus also damaging its physicomechanic properties. Hence, even though this method of conditioning improved the bond strength, other studies to evaluate the effects of this surface treatment on the physicomechanic - bility and integrity of the posts. The current study is limited to one better understanding of the effects of dif- ferent acids and acid-etching times on the bond strength of core buildup materials to - ating the effects of different post and core materials using artificial aging methods are recommended. To assess long-term dura- bility and for improved simulation of the in vivo environment, further treatments such as mechanical loading and thermal cycling could be applied. CONCLUSION Within the limits of the present study, it was concluded that both the different acids and acid-etching times significantly influ- enced the push-out bond strength between the composite core buildup material and P posts, all acid-etching procedures tested significantly increased bond strength when compared with the control group. Although the bond strength was increased by pro- longed acid etching, the microstructure of The use of acid treatments seems to be more practical than the other applications. However, type and concentration of acid © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
  • VOLUME 43 1 2012 QUINTESSENCE INTERNATIONAL Güler et al gels and application time is an essential factor to achieve optimal bond strength application. Additionally, acid etching the need for additional chairside treatments. REFERENCES 1. Radovic I, Monticelli F, Goracci C, et al. The effect of sandblasting on adhesion of a dual-cured resin composite to methacrylic fiber posts: Microtensile bond strength and SEM evaluation. J Dent 2007;35: 496–502. 2. Schwartz RS, Robbins JW. Post placement and restoration of endodontically treated teeth: A litera- ture review. J Endod 2004;30:289–301. 3. Perdigão J, Gomes G, Lee IK. The effect of silane on the bond strengths of fiber posts. Dent Mater 2006;22:752–758. 4. Asmussen E, Peutzfeldt A, Heitmann T. Stiffness, elastic limit, and strength of newer types of end- odontic posts. J Dent 1999;27:275–278. 5. Valandro LF, Yoshiga S, De Melo RM, et al. Microtensile bond strength between a quartz fiber post and a resin cement: Effect of post surface con- ditioning. J Adhes Dent 2006;8:105–111. 6. Balbosh A, Kern M. Effect of surface treatment on retention of glass-fiber endodontic posts. J Prosthet Dent 2006;95:218–223. 7. Gesi A, Magnolfi S, Goracci C, Ferrari M. Comparison of two techniques for removing fiber posts. J Endod 2003;29:580–582. 8. de Rijk WG. Removal of fiber posts from endodonti- cally treated teeth. Am J Dent 2000;13:19B–21B. 9. Akkayan B, Gulmez T. Resistance to fracture of end- odontically treated teeth restored with different post systems. J Prosthet Dent 2002;87:431–437. 10. Newman MP, Yaman P, Dennison J, Rafter M, Billy E. Fracture resistance of endodontically treated teeth restored with composite posts. J Prosthet Dent 2003;89:360–367. 11. Aksornmuang J, Foxton RM, Nakajima M, Tagami J. Microtensile bond strength of a dual cure resin core material to glass and quartz fiber posts. J Dent 2004;32:433–450. 12. Sadek FT, Monticelli F, Goracci C, Tay FR, Cardoso PEC, Ferrari M. Bond strength performance of differ- ent resin composites used as core materials around fiber posts. Dent Mater 2007;23:95–99. 13. Glazer B. Restoration of endodontically treated teeth with carbon fibre posts—A prospective study. J Can Dent Assoc 2000;66:613–618. 14. Naumann M, Blankenstein F, Dietrich T. Survival of glass fibre reinforced composite post restorations after 2 years. An observational clinical study. J Dent 2005;33:305–312. 15. Ferrari M, Vichi A, Mannocci F, Mason PN. Retrospective study of the clinical performance of fiber posts. Am J Dent 2000;13:9B–13B. 16. Monticelli F, Ferrari M, Toledano M. Cement sys- tem and surface treatment selection for fiber post luting. Med Oral Patol Oral Cir Bucal 2008; 13:E214–E221. 17. Mannocci F, Sheriff M, Watson TF, Vallittu PK. Penetration of bonding resins into fibre reinforced composite posts: A confocal microscopic study. Int Endod J 2005;38:46–51. 18. Schmage P, Cakir FY, Nergiz I, Pfeiffer P. Effect of sur- face conditioning on the retentive bond strengths of fiber reinforced composite posts. J Prosthet Dent 2009;102:368–377. 19. Bitter K, Noetzel J, Neumann K, Kielbassa AM. Effect of silanization on bond strengths of fiber posts to various resin cements. Quintessence Int 2007;38:121–128. 20. Monticelli F, Osorio R, Toledano M, Goracci C, Tay FR, Ferrari M. Improving the quality of the quartz fiber post core bond using sodium ethoxide etching and combined silane/adhesive coupling. J Endod 2006;32:447–451. 21. Rathke A, Haj-Omer D, Muche R, Haller B. Effectiveness of bonding fiber posts to root canals and composite core build-ups. Eur J Oral Sci 2009; 117:604–610. 22. Choi Y, Pae A, Park EJ, Wright RF. The effect of sur- face treatment of fiber-reinforced posts on adhe- sion of a resin-based luting agent. J Prosthet Dent 2010;103:362–368. 23. Schmage P, Nergiz I, Herrmann W, Ozcan M. Influence of various surface-conditioning meth- ods on the bond strength of metal brackets to ceramic surfaces. Am J Orthod Dentofacial Orthop 2003;123:540–546. 24. Vano M, Goracci C, Monticelli F, et al. The adhesion between fibre posts and composite resin cores: The evaluation of microtensile bond strength following various surface chemical treatments to posts. Int Endod J 2006;39:31–39. 25. Yavirach P, Chaijareenont P, Boonyawan D, et al. Effects of plasma treatment on the shear bond strength between fiber-reinforced composite posts and resin composite for core build-up. Dent Mater J 2009;28:686–692. 26. Magni E, Mazzitelli C, Papacchini F, et al. Adhesion between fiber posts and resin luting agents: A microtensile bond strength test and an SEM investigation following different treatments of the post surface. J Adhes Dent 2007;9:195–202. 27. Wrbas KT, Schirrmeister JF, Altenburger MJ, Agrafioti A, Hellwig E. 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  • e8 VOLUME 43 1 2012 QUINTESSENCE INTERNATIONAL Güler et al 28. Bitter K, Priehn K, Martus P, Kielbassa AM. In vitro evaluation of push-out bond strengths of various luting agents to tooth-colored posts. J Prosthet Dent 2006;95:302–310. 29. Asmussen E, Peutzfeldt A, Sahafi A. Bonding of resin cements to post materials: Influence of surface energy characteristics. J Adhes Dent 2005;7:231–234. 30. Goracci C, Raffaelli O, Monticelli F, Balleri B, Bertelli E, Ferrari M. The adhesion between prefabricated FRC posts and composite resin cores: Microtensile bond strength with and without post-silanization. Dent Mater 2005;21:437–444. 31. Bitter K, Kielbassa AM. Post-endodontic restorations with adhesively luted fiber-reinforced composite post systems: A review. Am J Dent 2007;20:353–360. 32. Bitter K, Meyer-Lueckel H, Priehn K, Martus P, Kielbassa AM. Bond strengths of resin cements to fiber-reinforced composite posts. Am J Dent 2006; 19:138–142. 33. Sahafi A, Peutzfeldt A, Asmussen E, Gotfredsen K. Bond strength of resin cement to dentin and to surface-treated posts of titanium alloy, glass fiber, and zirconia. J Adhes Dent 2003;5:153–162. 34. Monticelli F, Toledano M, Tay FR, Cury AH, Goracci C, Ferrari M. Post-surface conditioning improves interfacial adhesion in post/core restorations. Dent Mater 2006;22:602–609. 35. Albashaireh ZS, Ghazal M, Kern M. Effects of end- odontic post surface treatment, dentin condition- ing, and artificial aging on the retention of glass fiber-reinforced composite resin posts. J Prosthet Dent 2010;103:31–39. 36. Schmage P, Pfeiffer P, Pinto E, Platzer U, Nergiz I. Influence of oversized dowel space preparation on the bond strengths of FRC posts. Oper Dent 2009;34:93–101. © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
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