340 likes | 1.09k Views
Dent 5801 Operative Dentistry I Oct 9 th , 2007. Resin-modified Glass-ionomer Materials. Daranee Versluis-Tantbirojn Division of Operative Dentistry Department of Restorative Sciences. Learning objectives. Students will be able to.
E N D
Dent 5801 Operative Dentistry I Oct 9th, 2007 Resin-modified Glass-ionomer Materials Daranee Versluis-Tantbirojn Division of Operative Dentistry Department of Restorative Sciences
Learning objectives Students will be able to • Understand clinical behavior of glass-ionomers from the material viewpoint • Apply scientific information from the literature for clinical decisions about the use of glass-ionomers • Appropriately use glass-ionomers in restorative dentistry
Recall... DENT 5351 Dental cements, Dr. Combe, Feb 2, 2007 + pendant methacrylate groups Polymerization Resin-modified glass-ionomer Acid-base reaction
Siliceous hydrogel Glass core Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ CO-O- CO-O- Ca2+ Al3+ Al3+ Al3+ Al3+ Al3+ PO43- F- F- F- F- F- CO-O- CO-O- Ca2+ CO-O- Tooth structure -O-CO -O-CO PO43- CO-O- CO-O- Ca2+ CO-O- CO-O- PO43- CO-O- Ca2+ CO-O- CO-O- PO43- Ca/Al polyacrylate matrix Background: Chemistry and setting reactions polyalkenoic acids + calcium fluoroalumino silicate glass + methacrylate copolymer • Conventional GIs • (Acid-based reaction) • Ca2+ = initial set (minutes) • Al3+ = final set (days, weeks, months) • Resin-modified GIs Light initiated or autocure (set w/o light) methacrylate copolymer (resin-modified GI) Drawing adapted from Albers HF 1996, Tooth-color Restoratives.
True glass ionomers Conventional or ‘self-cured’ ‘light-cured’ Resin-modified acid-base reaction • Mixing • Cure in the dark
(Wilson & Kent 1972) (Bowen 1963) Glassionomer cement Resin composite Polyacid-modified composite(compomer) Resin-modified GI ‘Giomer’ ‘Hybrid ionomer composite’ (Geristore) True glass ionomers
Glass ionomers in restorative dentistry * * Fuji II LC Fuji IX Ketac Molar Ketac Fil Restorative (Filling) Vitrebond Lining * * Vitrebond Plus Ketac Bond Fuji Lining RelyX Luting RelyX Luting Plus Luting * FujiPlus FujiCem * * presently used in Operative preclinic & clinic
Ion exchange layer • Adhesion to tooth structures Glass core Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ CO-O- CO-O- Ca2+ Al3+ Al3+ Al3+ Al3+ Al3+ PO43- F- F- F- F- F- CO-O- CO-O- Ca2+ CO-O- Tooth structure -O-CO -O-CO PO43- CO-O- CO-O- Ca2+ CO-O- CO-O- PO43- CO-O- Ca2+ CO-O- CO-O- PO43- Advantages of glass ionomers • Release ions (F-) affect balance betweende/remin • ‘Non-irritant’ • Translucent • Better mechanical properties Compare with other cements
Glass ionomers: Use with caution • Inadequate physical properties * • Sensitive to water gain/loss * • Esthetic compromise * • Anticaries property is questioned • Adhesion property is not comparable to composite + dentin adhesive * More crucial if used as a permanent filling material
GIs cannot be used as permanent restorative material in stress-bearing areas Major physical failure 58 months • Bulk fracture • Marginal fracture • Poor anatomic form (wear) • Dissolution/disintegration Clinical failure of class-II restorations of a highly viscous glass-ionomer material over a 6-year period: A retrospective study Scholtanus JD, Huysmans MCDNJM J Dent 2007;35:156-62 Esthetic compromise • Opaque • Surface finish
Use with cautions • Sensitive to water gain/loss Maintain water balance during initial setting • Resin-modified GI restoratives (GC Fuji II LC) • Resin protects cement from water • Fast-set GIs (GC Fuji IX) • Wait 3-6 min before polishing • Polish with water coolant to prevent dehydration • Apply unfilled resin to protect surface
Plaque or acid medium Z250 Vitrebond Plus/Z250 Adapted from Hicks • Anticaries property is questioned? In vitro anticariogenic potential of GIs is known How is it under clinical conditions?
Anticaries property Questionable? A systemic review shows no overall evidence for or against a treatment effect of inhibition of secondary caries by glass ionomer restoration 28 studies from 1970 to 1996; total of 3965 participants; high caries risk • 5 positive studies • No secondary caries in GI; secondary caries in control • 19 neutral studies • No secondary caries in either group • or secondary caries present in both groups • 4 negative studies • Secondary caries in GI; no secondary caries in control Randall RC, Wilson NH. J Dent Res 1999;78:628-637 How would the data apply to present glass ionomers?
Anticaries property Questionable? Glass ionomers reduce recurrent caries in high-risk patients who do not routinely use topical fluoride. • Restorations in xerostomic patients: composite or amalgam vs GI • Patients were instructed to use NaF gel daily • At 2 years recall: • No recurrent caries was found in the fluoride users • No recurrent caries associated with conventional GI • In fluoride non-users,8 composite and 1 RMGI had recurrent caries & higher incidence of caries at amalgam cavosurface margins McComb D, Erickson RL, Maxymiw WG, Wood RE Operative Dentistry 2002;27:430-7 Haveman CW, Summitt JB, Burgess JO, Carlson K JADA 2003;134:177-84
Use GI restorative material for caries control G. Mount • 67 Cl V composite and 65 Cl V glass ionomer cement • After 5 years, 1% of glass ionomer and 6% of composite restorations had become carious • Approximately twice as much marginal staining around the composite as around the glass ionomers. • Tyas MJ. Australian Dental Journal 1991; 36:236-9. • Cariostatic effect of glass ionomer cement: a five-year clinical study.
Adhesion property of glass ionomers Bond strength (MPa)* Enamel Dentin GI Restorative ~ 4-14 ~ 4-10 Composite + adhesive ~ 30 ~ 25 GI liner ~ 3-7 ~ 4-10 GI luting cement ~ 6-10 ~ 2-6 Metal Porcelain GI luting cement ~ 7-12 (sandblast) ~ 8-14 (Zr, Alumina) Resin cement + adhesive ~ 15-25 ~ 25 (etched porcelain & ceramic primer) * Shear mode; 3M and GC products; 3M Product Profiles
Bond strengths of glass ionomers are not comparable to composite + adhesive or resin cement • Should I use GI luting cement or resin cement? • Should I use GI restorative or composite? • Should I use GI liner or not? • What are the most likely errors that affect adhesion? Other issues to consider related to adhesion: • post-operative sensitivity • microleakage • pulp protection
GI luting vs Resin cement • Post-operative sensitivity was a problem with GI lutings in 1980’s–1990’s Studies showed that GI lutings did not cause post-op sensitivity. • No differences betweenGICs (conventional & resin-modified) or a zinc phosphate luting cement Kern M, Kleimeier B, Schaller HG, Strub JR. J Prosthet Dent 1996;75:159-62 Jokstad A. Int J Prosth 2004;17:411-6 • Paste-paste resin-modified GI luting cement did not cause post- operative sensitivity (290 restorations in 268 patients). Yoneda S, Morigami M, Sugizaki J, Yamada T. Quintessence Int. 2005;36:49-53 • The level of tooth sensitivity post-cementation(1-4 wks)was less than pre-operatively in both conventional and resin-modified GICs. Smales RJ, Gale MS. Oper Dent 2002;27:442-6
GI luting vs Resin cement • Post-operative sensitivity was a problem with GI because: • Dentin was desiccated • Anhydrous glass ionomer cement Should I use GI luting cement or resin cement? • GI luting cement for indirect metal restoration (inlays, onlays, full gold crown) and PFM. • Simple application & easy clean up • Resin cement for esthetic indirect restorations (porcelain, ceramics, indirect composite) and indirect metal or PFM where additional retention is required (minimal tooth structure). Indications
Example of instruction for use of a resin-modified glass-ionomer luting cement (3M RelyX Luting Plus) • Pulp protection if necessary • Clean tooth, rinse and lightly dry leaving tooth surface moist. Remove excess cement at a waxy stage (after 2 minutes from placement) Mix with spatula for 20 second Working time 2.5 minutes
% Retention Composite RMGI References 3 years 2 years 2 years 86 81 70 55 96 100 Folwaczny et al., 2001 Brackett et al., 2003 Onal and Pamir, 2005 Should I use GI restorative or composite? Clinical studies showed mixed results in Cl V retention However, deficiencies in color stability, anatomic form, or wear limit the longevity of glass ionomer restorations. • Post-operative sensitivity of composite restorations • Polymerization shrinkage • Microleakage • Sub-optimal bonding
Post-operative sensitivity Painful on pressure Composite leakage & Post-op sensitivity Anecdote: No sensitivity after replacing composite with glass ionomer restoration
Example of resin-modified glass-ionomer restorative (GC Fuji II LC) Cavity conditioner (recommended for GC products) • Enhanced bonding by removing smear layer • Mild (25%) polyacrylic acid • Apply 10 seconds on dentin and enamel, rinse, blot. Surfaces should appear moist (glistening) before applying glass ionomer
Should I use GI liner? Bond strength (MPa)* Enamel Dentin Composite + adhesive ~ 30 ~ 25 GI liner ~ 3-7 ~ 4-10 Bond strength of GI liner is not comparable to composite However, GI liners prevent post-operative sensitivity. When GI liner (e.g., Vitrebond or Fuji Lining Cement) is applied to the deepest portions of Class I, II, and V tooth preparations before any bonding systems are used, clinicians have reported that it almost totally prevents postoperative tooth sensitivity. Gordon J Christensen, JADA 2002;133:229-231.
Should I use GI liner? Less microleakage with GI liners • Class II amalgam restorations with GI liners had significantly less microleakage than did restorations with calcium hydroxide liners or dentin alone (without GI). Rabchinsky J, Donly KJ. Int J Perio Rest Dent 1993;13:378-83 Marchiori S et al., Quintessence Int 1998;29:637-42 ‘Dycal’ should always be covered with GI liner • Ca(OH)2 liner adversely affects bonding efficacy of dentin adhesive Krejci I, Lutz F, J Dent 1990;18:263-70 • Ca(OH)2 liners ‘wash out’ leaving a void underneath the restoration Novickas D, Fiocca VL, Grajower R, Oper Dent 1989;14:33-9 • How good is Dycal to withstand amalgam condensation?
Should I use GI liner? Do not use RMGI when pulp is exposed. When in direct contact with exposed pulp, Vitrebond triggered a persistent inflammatory reaction. Am J Dent 2000;13:28-34 do Nascimento AB, Fontana UF, Teixeira HM, Costa CA Biocompatibility of a RMGIC applied as pulp capping in human teeth But GI liner is better than dentin adhesive in deep cavity. Pulp response in deep class V composite restoration lined with Vitrebond was better than total-etched adhesive. Dent Mater 2003;19:739-46 Costa CA, Giro EM, do Nascimento AB, Teixeira HM, Hebling J Short-term evaluation of the pulpo-dentin complex response to a resin-modified glass-ionomer cement and a bonding agent applied in deep cavities.
How deep is deep? ~ 1 mm below DEJ* 1-2 mm from pulp* >1 mm from DEJ* 0.5-1 mm from pulp* (‘pinkish’) GI liner optional Etch & Adhesive Composite GI liner Etch & Adhesive Composite Dycal GI liner Etch & Adhesive Composite * The numbers are arbitrary for illustration purposes. It depends on the tooth, location, pulp recession, etc.
Example of resin-modified glass-ionomer liner (3M Vitrebond Plus) Use clean Dycal carrier Followed by etching, bonding, filling