Vital tooth cleaning for cementation of indirect restorations: A review
By Edward E. Hill, DDS, MS
Barry Rubel, DMD
Featured in General Dentistry, July/August 2009
Pg. 392-395
Posted on Thursday, July 02, 2009
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This article reviews factors that must be considered to select the best technique for cleaning a vital tooth prior to cementation of a definitive restoration. The dental literature offers many suggestions with supporting rationales. In cases where provisional cement has been present or contrast powder has been used, some mechanical cleaning (with fine pumice or prophy paste) appears to be justified. The value of soaps or other chemicals is questionable except perhaps as topical disinfectants. Dentists should be aware that a cleansing agent may have a negative or positive effect on bond strength, depending on the adhesive system chosen. It may be necessary to tailor the particular method of tooth cleaning to the cement that is to be used.
Received: September 10, 2008
Accepted: November 10, 2008
Cementing an indirect restoration is an important end step in a very meticulous process. The cement can serve primarily as a filler, providing only micromechanical retention, or it can establish chemical bonds to the tooth and restoration.1 In either case, substrates that are to be joined should be prepared properly to guarantee good cement adaptation and optimize the chance for a functional, long-lasting, and comfortable restoration.
Preparation of a metal or metal-ceramic restoration for definitive luting involves air abrasion with fine aluminum-oxide particles followed by ultrasonic or steam cleaning. All-ceramic restorations (depending on the ceramic material) may require cleaning or additional hydrofluoric acid-etching and application of a silane coupling agent.2 Whether a vital tooth should be cleaned—and if so, the best technique to use prior to cementation of a definitive restoration—may not always be so well-defined. This article reviews factors that could influence a dentist’s decision-making process concerning this procedure.
Background
According to Shillingburg et al, cleaning prepared tooth structure using wet flour of pumice on a rubber cup will “improve the retention somewhat.”3 Such cleaning is intended to remove provisional material, debris, blood, saliva, and (if present) residual eugenol, which may interfere with the retention of luting agents. Tooth preparation into dentin produces a film of particulate matter (referred to as the smear layer) on the cut surface. This layer primarily contains tooth debris but also includes some organic matter (that is, blood, saliva, and micro-organisms).4 The smear layer helps to prevent bacterial access into the tubules and reduces dentin surface wetness at cementation from pulpal fluid seepage. Some oral micro-organisms trapped during cementation can survive and grow. If microleakage occurs, or if the dentinal tubules are open far enough to allow for a source of nourishment, pulpal damage or recurrent caries could result.5 It would seem that eliminating surface bacteria (including those that cause caries) without unblocking the tubules may be an important objective of the cleaning process.
Literature review
Brannstrom and Johnson reported on how various conditioners and cleaning agents affected ground dentin.5 Water spray or scrubbing for five seconds with a cotton pellet (soaked in either water or a mixture of ether-acetone) did little to disturb the smear layer. Scrubbing for 60 seconds with a water-soaked pellet resulted in a cleaner surface but much debris remained. Scrubbing for five seconds with a pellet soaked in 30% hydrogen peroxide followed by 95% alcohol resulted in a debris layer of varying thickness; most of the dentinal tubules remained blocked. The cleanest dentin (without unplugging the tubules) resulted after scrubbing for five seconds and applying microbicidal 3% sodium fluoride solution for 60 seconds.
Demineralizing solutions (such as 50% citric acid, 50% phosphoric acid, or 20% lactic acid) removed the entire layer of grinding debris while widening the openings of the tubules.5 Surface widening of tubules on a vital tooth may or may not be desired, depending on whether etching will be followed by placement of a bonding agent prior to cementation.
Dahl reported on how cleaning with wet pumice affected the retention of zinc phosphate and polycarboxylate cements.6 The 1978 study did not specify how much time was devoted to cleaning; however, it was noted that polishing with pumice reduced the retention of zinc phosphate slightly while increasing that of polycarboxylate. These results were understandable, since a clean surface favors chemical bonding offered by polycarboxylate and a non-smooth surface favors mechanical retention provided by zinc phosphate. Rubbing cut dentin with a cotton pellet soaked in a phosphate-buffered solution of cocoamphodiacetate, benzalkonium chloride, and disodium edentate dehydrate (Tubulicid, Global Dental Products) removed the smear layer while leaving the dentinal tubules sealed and did not reduce the retention of zinc phosphate but did lower that of polycarboxylate. The authors postulated that Tubulicid may have left a film on cut dentin that interfered with chemical bonding.6
Duke et al examined several methods for cleaning cut dentin and found that both wet pumice and a representative commercial prophylaxis paste removed most of the smear layer and zinc oxide-eugenol residue, although the authors did not state how much time was devoted to cleaning. The prophy paste resulted in a smoother surface, while the smear layer was virtually undisturbed when cut dentin was wiped with either a cotton pellet soaked in 3% hydrogen peroxide or a degreasing agent containing 50% ethyl acetate.7
A 1988 study by Button et al examined how various dentin cleaning methods affected metal crown retention when glass ionomer and zinc polycarboxylate cements were used.8 For both cements, the highest values for retention occurred after teeth were cleaned with wet flour of pumice; however, retentive values for glass ionomer did not differ significantly when dentin was cleaned with pumice or prophy paste or cleaned superficially using only an explorer. Retention for both cements was reduced significantly when superficial tooth cleaning was combined with a cotton pellet soaked in a degreasing agent containing 50% ethyl acetate. The authors concluded that the particular method of tooth cleaning prior to definitive cementation should be appropriate for the cementing agent that is to be used.8
Eugenol from residual provisional cement has been shown to have a detrimental effect on the bond strength of both resin-modified glass ionomer (RMGI) and some adhesive resin cements.1,9 Some of the newer self-etching adhesives on the market appear to be adversely effected by eugenol.10,11 A 1997 study reported that using wet pumice alone may not be entirely effective for removing all remnants of provisional cement containing eugenol prior to adhesive luting.12
Bachmann et al examined the shear bond strength of four dentin bonding agents, as prepared dentin was cleaned with four different soaps (lauryldimethylaminoxide; a mixture of anionic, non-ionic, and amphoteric washing substances; sodium laurylsulphate; and nonylphenolethylenglycol) (in combination with flour of pumice) for 10 seconds prior to the use of a provisional cement containing eugenol.13 Compared to wet pumice alone, all of the soaps decreased the shear bond strength of the various materials tested and their use was not recommended for removing provisional cement residue.13 Conversely, Rosin et al used pumice containing an anionic detergent to clean prepared dentin and found that the combination did not interfere with the bond strength of either Clearfil SE Bond (J. Morita USA, Inc.) or Adper Scotchbond Multi-Purpose Plus (3M ESPE).14
Cavidry (Parkell), a combination of ethyl acetate (99%) with methyl ethyl ketone, is marketed as a degreasing cleaner designed to dissolve hard-to-remove contaminants that could compromise cementation. A 1991 study by Olin et al reported that using Cavidry to help remove petroleum-based lubricant from prepared canals improved cast post retention for zinc phosphate and glass ionomer cements compared to cleaning canals with water only.15 There is no literature supporting Cavidry’s effectiveness in terms of removing eugenol. However, eugenol is somewhat soluble in oxygenated organic solvents; as a result, one would assume that wiping a tooth with a cotton pellet soaked in an aldehyde (Cavidry or Cavilax (Premier Dental)) would remove some superficial eugenol (if present) and could denature the surface proteins of micro-organisms. Wiping a tooth with a volatile organic solvent also might cause some desiccation (resulting in the formation of reparative dentin) but that should not pose a significant risk to the pulp, provided that a good protective zone of dentin is present.16
Recent studies have proposed immediate dentin sealing, in which dentin is sealed with a bonding agent after tooth preparation is completed but before impressions are taken. This technique may improve the microtensile bond strength for resin-bonded indirect restorations (depending on the bonding agent) and reduce dentin sensitivity, both during the provisional period and at definitive cementation.17-19 Stavridakis et al used a scanning electron microscope to examine the loss of film thickness for two immediate dentin bonding agents, Optibond (Kerr Dental) and Syntac Classic (Ivoclar Vivadent, Inc.) resulting from tooth cleaning with air abrasion (50 µ aluminum oxide for five seconds) and a commercial prophy paste (Depurdent, Dr. Wild & Co AG) applied on a nylon brush at 1,000 rpm for five seconds. Neither air abrasion nor prophy paste removed the entire layer of either bonding agent; in any case, the amount removed was not consistent for each method.20
Rosenstiel et al have suggested using Consepsis (Ultradent Products, Inc.) for cleaning teeth prior to cementation, either as a scrub or added to pumice.2 Consepsis is a solution of flavored 2% chlorhexidine (pH = 6) marketed as a cavity cleaning agent and disinfectant. Chlorhexidine is antimicrobial and may reduce the risk of bacterial invasion into open dentinal tubules by providing a degree of surface disinfection. The manufacturer states that it will increase bonding strength.21 That claim may be somewhat misleading, since their advertising cites only a single 1995 study that cleaned dentin with seven different cavity disinfectants to determine the shear bond strength for three dentinal adhesive systems. Cao et al reported that the disinfectants decreased dentin shear bond strength for the three adhesive systems tested, except for Consepsis, whose results were more or less identical to untreated controls.22 Recent studies have demonstrated that there is no clear consensus on the value of using cavity cleansers prior to either etching or the application of self-etching bonding agents.23-25
Using CAD/CAM technology to fabricate an indirect restoration chairside eliminates both the need for temporization and the potential for provisional cement to contaminate freshly prepared dentin.26 Using a rubber dam reduces the presence of saliva and allows for a more thorough cleaning of the tooth for definitive bonding or cementation; however, the preparation must be coated with a powder bonding agent and a water-insoluble metal-oxide powder (titanium dioxide plus other metal oxides) to improve tissue contrast for an optical impression.26 Some removal of the powder can be accomplished with water spray, but mechanical scrubbing is commonly needed. Residual powder has not been investigated or reported as a problem.
Summary
The dental literature offers many suggestions for cleaning prepared tooth structure prior to bonding or cementation of a definitive restoration. When provisional cement has been present or when contrast powder has been used, some mechanical cleaning (using either fine pumice or prophy paste) would appear to be necessary. Soaps or other chemicals might be used as topical disinfectants but their value is questionable for cleaning prepared teeth. When resin bonding must be performed, the dentist should be aware that a cleansing agent may have a negative or positive effect, depending on the adhesive system. The particular method of tooth cleaning may need to be tailored to the definitive cement used.8
Author information
Drs. Hill and Rubel are associate professors, Department of Care Planning and Restorative Sciences, University of Mississippi School of Dentistry in
References
1. Hill EE. Dental cements for definitive luting: A review and practical clinical considerations. Dent Clin North Am 2007;51(3):643-658, vi.
2. Rosenstiel SF, Land MF, Fujimoto J. Contemporary fixed prosthodontics, ed. 4.
3. Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett S. Fundamentals of fixed prosthodontics, ed. 3.
4. Eick JD, Wilko RA, Anderson CH, Sorensen SE. Scanning electron microscopy of cut tooth surfaces and identification of debris by use of the electron microprobe. J Dent Res 1970;49(6):1359-1368.
5. Brannstrom M, Johnson G. Effects of various conditioners and cleaning agents on prepared dentin surfaces: A scanning electron microscopic investigation. J Prosthet Dent 1974;31(4):422-430.
6. Dahl BL. Effect of cleaning procedures on the retentive ability of two luting cements to ground dentin in vitro. Acta Odontol Scand 1978;36:137-142.
7. Duke ES, Phillips RW, Blumershine R. Effects of various agents in cleaning cut dentine. J Oral Rehabil 1985;12(4):295-302.
8. Button GL, Moon PC, Barnes RF, Gunsolley JC. Effect of preparation cleaning procedures on crown retention. J Prosthet Dent 1988;59(2):145-148.
9. Terata R, Nakashima K, Kubota M. Effect of temporary materials on bond strength of resin-modified glass ionomer luting cements to teeth. Am J Dent 2000;13(4):209-211.
10. Peutzfeldt A, Asmussen E. Influence of eugenol-containing temporary cement on bonding of self-etching adhesives to dentin. J Adhes Dent 2006;8(1):31-34.
11. Carvalho CN, de Oliveira Bauer JR, Loguercio AD, Reis A. Effect of ZOE temporary restoration on resin-dentin bond strength using different adhesive strategies. J Esthet Restor Dent 2007;19(3):144-152.
12. Paul SJ, Scharer P. Effect of provisional cements on the bond strength of various bonding systems on dentine. J Oral Rehabil 1997;24(1):8-14.
13. Bachmann M, Paul SJ, Luthy H, Scharer P. Effect of cleaning dentine with soap and pumice on shear bond strength of dentine-bonding agents. J Oral Rehabil 1997;24(6):433-438.
14. Rosin C, Arana-Chavez VE, Netto NG, Luz MA. Effects of cleaning agents on bond strength to dentin. Braz Oral Res 2005;19(2):127-133.
15. Olin PS, Cederbaum A, Donahue JL. Effects of lubrication on the retention of tapered and parallel cast post and cores. J Prosthet Dent 1991;66(1):45-49.
16. Brannstrom M. The effect of dentin desiccation and aspirated odontoblasts on the pulp. J Prosthet Dent 1968;20(2):165-171.
17. Yim NH, Rueggeberg FA, Caughman WF, Gardner FM, Pashley DH. Effect of dentin desensitizers and cementing agents on retention of full crowns using standardized crown preparations. J Prosthet Dent 2000;83(4):459-465.
18. Magne P. Immediate dentin sealing: A fundamental procedure for indirect bonded restorations. J Esthet Restor Dent 2005;17(3):144-155.
19. Magne P, Kim TH, Cascione D, Donovan TE. Immediate dentin sealing improves bond strength of indirect restorations. J Prosthet Dent 2005; 94(6):511-519.
20. Stavridakis MM, Krejci I, Magne P. Immediate dentin sealing of onlay preparations: Thickness of dentin bonding agent and effect of surface cleaning. Oper Dent 2005;30(6):747-757.
21. Consepsis & Consepsis V [package insert]. Available at: http://www.ultradent.com/products/instructions/consepsis_consepsis_v.pdf. Accessed August 19, 2008.
22. Cao DS, Hollis RA, Christensen RP, Christensen GJ. Effect of tooth disinfecting procedures on dentin shear bond strength. J Dent Res 1995;74:73 (AADR Abstract No. 493).
23. Sarac D, Bulucu B, Sarac YS, Kulunk S. The effect of dentin-cleaning agents on resin cement bond strength to dentin. J Am Dent Assoc 2008;139(6):751-758.
24. Owens BM, Lim DY, Arheart KL. The effect of antimicrobial pre-treatments on the performance of resin composite restorations. Oper Dent 2003;28(6):716-722.
25. Turkun M, Turkun LS, Kalender A. Effect of cavity disinfectants on the sealing ability of nonrinsing dentin bonding resins. Quintessence Int 2004;35(6):469-476.
26. Jedynakiewicz NM, Martin
Manufacturers
Dr. Wild & Co AG,
Global Dental Products,
Ivoclar Vivadent, Inc.,
J. Morita USA, Inc., Irvine, CA; 888.566.7482, www.jmoritausa.com
Kerr Dental,
Parkell,
Premier Dental, Plymouth Meeting, PA; 888.670.6100, www.premusa.com
Ultradent Products, Inc.,
3M ESPE,
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General Dentistry, July/August 2009 , Volume 57 , Issue 2
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