Amalgam repair

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amalgam repair comparison

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Amalgam repair

  1. 1. Amalgam repair Boondarick Niyatiwatchanchai Tuesday, August 13, 13
  2. 2. Replacement of restoration Tuesday, August 13, 13
  3. 3. Replacement of restoration • secondary caries • marginal defect • cusp fracture Tuesday, August 13, 13
  4. 4. Replacement of restoration • secondary caries • marginal defect • cusp fracture Tuesday, August 13, 13
  5. 5. Replacement of restoration • secondary caries • marginal defect • cusp fracture Tuesday, August 13, 13
  6. 6. Replacement of restoration • secondary caries • marginal defect • cusp fracture Tuesday, August 13, 13
  7. 7. Replacement of restoration • secondary caries • marginal defect • cusp fracture Tuesday, August 13, 13
  8. 8. Replace or repair Tuesday, August 13, 13
  9. 9. Replace or repair • • • • • • Tuesday, August 13, 13 loss of dental tissue increasing preparation/restoration size cost time consuming technically difficult Potentially damage to pulp
  10. 10. Replace or repair • • • • • • Tuesday, August 13, 13 loss of dental tissue increasing preparation/restoration size cost time consuming technically difficult Potentially damage to pulp
  11. 11. Benefit of repair • more conservative of tissue • reduce risk of iatrogenic damage • reduce need for the use of local anesthesia • oppotunity to enhanced patient experience • saving in time and resources • esthetic Tuesday, August 13, 13
  12. 12. Benefit of repair • more conservative of tissue • reduce risk of iatrogenic damage • reduce need for the use of local anesthesia • oppotunity to enhanced patient experience • saving in time and resources • esthetic Tuesday, August 13, 13
  13. 13. Resin composite as repair material • interfacial bond between amalgam and resin composite • strengthening of the tooth-material interface • veneering of amalgam for esthetic Tuesday, August 13, 13
  14. 14. Development in adhesive technology • Improve sealing quality of amalgam repair Tuesday, August 13, 13
  15. 15. Still controversy • still in wide range of result attributed to various factors ex time , interface , effect of roughening , type of alloy Tuesday, August 13, 13
  16. 16. Tuesday, August 13, 13
  17. 17. Aim of the study • to assessed the repair quality of amalgam restorations at the amalgam-resin and resin tooth interfaces • using different • 1) surface finishing methods • 2) adhesive systems Tuesday, August 13, 13
  18. 18. Methods and materials • 55 caries-free intact human molars • stored in distilled water • clean and polished with pumice and rubber cup for 10 sec • occlusal cavity preparation using high speed hand piece with air/water spray Tuesday, August 13, 13
  19. 19. • Average facio-lingual width of cavies was approximately one-third of intercuspal width and 3 mm depth • restored with high copper , microfine lathe-cut amalgam(Cavex Avalloy) • • • • stored in distilled water for 24 hrs • divided into 5 groups( n=10/group) to receive the following adhesive system Tuesday, August 13, 13 thermo cycling in deionized water remove mesial and distal parts of the cavities one side was finished with a coarse diamond bur while the other was finished with fine diamond bur
  20. 20. • Group 1: All Bond 3 (BISCO, Inc, Schaumburg, IL, USA) (dual cure, etch&rinse adhesive system) • Group 2: Clearfil SE Bond+Alloy Primer (Kuraray, Okayama, Japan) (self-etch adhesive system with alloy primer) • Group 3: Kuraray DC Bond (Kuraray) (dual-cure, selfetch adhesive system) • Group 4: Xeno V (Dentsply DeTrey, Konstanz, Germany) (one-step, self-etch adhesive system) • Group 5: XP Bond (Dentsply DeTrey) (etch&rinse, selfpriming adhesive system) All of the cavities were restored with resin composite (TPH Spectrum, Dentsply DeTrey) and light polymerized with a halogen light of 500 mW/cm2 intensity Tuesday, August 13, 13
  21. 21. Tuesday, August 13, 13
  22. 22. • • • • • Thermocycled again • • digitally photographed Tuesday, August 13, 13 immersed in 0.5 basic fuchsin soluion 24 hr rinsing with distilled water embedded in epoxy resin sectioned mesiodistally with a slow speed diamond saw data analyzed with one-way ANOVA and poist hoc Tukey test
  23. 23. Result • All the groups exhibited microleakage between the amalgam-resin interface and the tooth-resin interface Tuesday, August 13, 13
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  37. 37. Result • there was no difference among each region when using all bond 3 • no statistical difference between the microleakage values of surfaces with either course or fine finish(p>0.05) • amalgam-resin surfaces exhibited statistically more microleakage than tooth-resin surfaces for the other adhesive systems Tuesday, August 13, 13
  38. 38. Tuesday, August 13, 13
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  40. 40. DISCUSSION • Amalgam comprises about 40% of the restoration being replaced with a median age of 12-15 years • A successful technique for the repair would be advantageous conservative Tuesday, August 13, 13
  41. 41. Alternative options for defective amalgam restoration • Rapairing • Sealing • Refurbishing Tuesday, August 13, 13
  42. 42. DISCUSSION • Replacing ditched amalgam restorations with other similar restorations resulted in significant dental structure loss • Previous studies report on 40%-70% bond strength archieved from amalgam-toamalgam repair • The trend of minimally invasive dentistry Tuesday, August 13, 13
  43. 43. DISCUSSION • In Vivo studies related to the repair of amalgam indicate a significant impact on the improvement of clinical performance of amalgam restoration with minimal intervention Tuesday, August 13, 13
  44. 44. Important factor • Interfacial bond between the joined surfaces • clean surfaces , roughening amalgam , adhesive for metallic Tuesday, August 13, 13
  45. 45. Microleakage test • useful methods for evaluating sealing performance of adhesive systems • image analysis to obtain quantitative results Tuesday, August 13, 13
  46. 46. Effect of roughening • Jessup and Vandewalle report improved bond strengths after roughening with carbide burs • Hadavi and others report similar result using carbide burs and diamond burs • However the results of the current in vitro study could not correlate microleakage and surface roughness of the joined surfaces Tuesday, August 13, 13
  47. 47. Use of bonding agent • Robert and others found the use of a bonding agent did not improve the degree of protection against microleakage • Ozer and others found significant improvement in microleakage especially amalgam-resin interface Tuesday, August 13, 13
  48. 48. Bonding systems • Etch and rinse • Self etch Tuesday, August 13, 13
  49. 49. Etch and rinse • Phosphoric acid etching of enamel and dentin • weak zone of uninfiltrated dentin • hydrolytic degradation of collagen Tuesday, August 13, 13
  50. 50. Self etch • increasing popularity • reduces application time and technique sensitivity • prevent hydrolytic degradation of bond • debate on efficacy of bonding to enamel Tuesday, August 13, 13
  51. 51. In this study • Total etch performed significantly better than self etch • alloy primer did not significantly improve sealing in the restoration comolex Tuesday, August 13, 13
  52. 52. All bond 3 • Hydrophobic , radiopaque-filled bonding resin and also HEMA-free • less prone to water sorption • Hydrophobic adhesives are expect to be more durable Tuesday, August 13, 13
  53. 53. • Better performance of etch and rinse systems may also be related to micromechanical interlocking of the resin system to acid etched surfaces • However additional roughening with coarse bur did not facilitate bonding both in amalgam and tooth surface Tuesday, August 13, 13
  54. 54. Conclusion • In term of preventing microleakage etch and rinse adhesive may be preferred for amalgam repair • The use of coarse versus fine diamond for preparation did not impact microleakage Tuesday, August 13, 13
  55. 55. Tuesday, August 13, 13
  56. 56. Primary Aim • To evaluate the effects of different amalgam conditioning methods on the tensile bond strength between amalgam and a nanohybrid resin composite restorative material , using various intraoral restoration repair systems • Study the nature of interfacial bond failure , using electron microscope Tuesday, August 13, 13
  57. 57. Null Hypothesis • There was no statistical difference in repair bond strengths between the various repair protocols Tuesday, August 13, 13
  58. 58. ion, which suggests that the fractured tooth is restorative procedures.12 Various factors may o cusp fracture of amalgam-restored teeth, k of adhesion of amalgam to tooth structures, iding no significant change in the fracture the cusps14 or in the amount of cuspal flexure15 uivalent unrestored teeth. These factors may be by the presence of undermined cusps, extensive ze, parafunctional activity, impact load, fatigue lusal disharmony.9 ional approach to the management of cusp eth which have been restored with amalgam has otal restoration replacement resulting in more ect restorations, or preparation for indirect Both of these procedures result in increased nd restoration size.16 This approach has been the ‘repetitive restoration cycle’17 and can result ssive weakening of the tooth through unnecesof sound tooth tissue, detrimental effects on the together with potential damage caused to h.18 me amalgam restorations with adjacent cusp bly those associated with an extensive secondon, will inevitably require replacement, it may be t some amalgam restorations with adjacent cusp be given extended longevity through repair .e. cusp replacement with or without partial of the amalgam restoration, allowing preservaortion of the restoration that presents no clinical hic evidence of failure). This more conservative vasive approach to the management of cusp cent to or involving the amalgam restoration, advantages, including: the tensile bond strength between amalgam and a nanohybrid resin composite restorative material, using various intra-oral restoration repair systems. The secondary aim was to the nature of interfacial failure, using scanning electron microscopy (SEM) and profilometry examinations of failed interfacial surfaces. The null hypothesis tested was that there was no statistical difference in repair bond strengths between the various repair protocols. Material and methods • 2. Materials and methods 2.1. Specimen preparation Specimen preparation One hundred and sixty poly(methymethacrylate) (PMMA) retention bases (Mould 1) (VisionTek Systems Ltd., Chester, UK) were prepared containing a central recess (width 5 mm, height 5 mm, depth 4 mm). A cavity of 2 mm diameter and 2 mm depth was prepared at the base of this central recess, to facilitate mechanical retention of the amalgam (Fig. 1). The amalgam (non-gamma 2, lathe-cut, high-copper alloy with 43% Ag, 25.4% Cu) (ANA 2000 Duet, Nordiska Dental AB, Angelholm, Sweden) was triturated according to the manufacturer’s instructions and then condensed with a hand instrument into the recess within the PMMA base. Specimens • 160 PMMA retention bases were prepare containing a central recess(width 5mm , height 5mm , depth 4mm) • cavity of 2mm diameter and 2mm depth was prepared at the base rvative of tooth tissue, k of iatrogenic damage, ed for the use of local anaesthesia, y for enhanced patient experience, ime and resources. t to amalgam repair procedures using bonded e use of resin composite as a repair material Tuesday, August 13, 13 Fig. 1 – Custom made retention base (Mould 1).
  59. 59. • • Triturated amalgam(non gamma2 , lathe-cut, high copper) • • Allow to set for 24 h • • Air-dried for 24 h Tuesday, August 13, 13 condensed with a hand instrument into the recess within the PMMA base polished with a wet 1200-grit silicon carbide disc at 300 rpm for 30s and cleaned for 10 min in ultrasonic bath stored in artificial saliva for 2 weeks to present an aging process
  60. 60. Surface conditioning method • Divided into 8 groups , each containing 20 specimen Tuesday, August 13, 13
  61. 61. 1 Group 1: Air-borne particle abrasion with 50 mm Al2O3 (Korox R, Bego, Bremen, Germany) using an intraoral sandblaster (Dento-PrepTM, RØNVIG A/S, Daugaard, Denmark) from a distance of 10 mm at a pressure of 2.5 bar for 4 s followed by application of Alloy primer (Kuraray, Japan) and Panavia 21 (Kuraray, Japan). 2 Group 2: Air-borne particle abrasion as for group 1 followed by application of Amalgambond Plus (Parkell, USA). 3 Group 3: Air-borne particle abrasion as for group 1 followed by application of ALLBOND 3 (Bisco, USA). 4 Group 4: Surface roughening with a diamond bur (Classic Diamond #521M, Dental Directory, Essex, UK) for 10 s and application of Alloy primer (Kuraray, Japan) and Panavia 21 (Kuraray, Japan). 5 Group 5: Diamond bur roughening as for group 4 followed by application of Amalgambond Plus (Parkell, USA). Group 6 6: Diamond bur roughening as for group 4 followed by application of ALL-BOND 3 (Bisco, USA) 7 Group 7: Silica coating with 30 mm SiO2 particles using an intra-oral sandblaster (3M ESPE, Germany) from a distance of 10 mm at a pressure of 2.5 bar for 4 s followed by application of the corresponding silane and bonding agents (ESPE-Sil and Visio-bond) of the CoJet System (3M ESPE, Germany) 8 Group 8 (control group): No surface conditioning and no adhesive system was used. Tuesday, August 13, 13
  62. 62. 17 journal of dentistry 40 (2012) 15–21 Table 1 – Description, composition and manufacturers of the intra-oral adhesive repair systems and composite resin material used in this study. Material Material description Alloy Primer + Panavia 21 Metal conditioning primer + dual-cure adhesive system Amalgambond Plus Self-cure etch and rinse adhesive system ALL-BOND 3 Dual-cure etch and rinse universal adhesive system CoJet-Sand Sand for coating substrate surface ESPE-Sil Silane coupling agent Visio-bond Adhesive bonding agent NANOSITTM Nano-hybrid composite resin restorative material Chemical composition Primer: 6-[(4-vinylbenzyl)propylamino]-l, 3,5-itriazine-2,4-dithione (VBATDT), 10-methacryloyloxydecyl dihydrogen phosphate (MDP adhesive monomer) Adhesive system: 10-methacryloyloxydecyl dihydrogen phosphate, dimethacrylate, silica filler META (4-methacryloxyethyl trimellitate anhydride), bisphenol-A-dimethyacrylate, HEMA (hydroxyethyl methacrylate), ethylene glycol methacrylate BisGMA (bisphenol-A-dimethyacrlate), urethane dimethacrylate, triethylene glycol dimethacrylate, silica filler Aluminium trioxide particles coated with silica, particles size: 30 mm 3-Methacryloxypropyltrimethoxysilane, ethanol Bisacrylate, aminodiol methacrylate, camphor-quinone, benzyl dimethyl ketale, stabilisers BisGMA (bisphenol-A-dimethyacrylate), HEMA (hydroethyl dimethacrylate), inorganic glass particles (57 vol%; 74 wt%), particle size: 2.0–0.2 mm were allowed to set for 24 h at 23.0 Æ 1.0 8C and were subsequently polished with a wet 1200-grit silicon carbide disc (Struers RotoPol 11, Struers A/S, Rodovre, Denmark) at 300 rpm for 30 s and cleaned for 10 min in an ultrasonic bath (Quantrex 90 WT, L&R Manufacturing Inc., Kearny, NJ, USA) Tuesday, August 13, 13 deionised water to eliminate possible contamicontaining Manufacturer Kuraray, Okayama, Japan Parkell, Farmingdale, NY, USA Bisco, Inc. Schaumburg, IL, USA 3M ESPE AG, Seefeld, Germany 3M ESPE AG, Seefeld, Germany 3M ESPE AG, Seefeld, Germany Nordiska Dental AB, Angelholm, Sweden Group 6: Diamond bur roughening as for group 4 followed by application of ALL-BOND 3 (Bisco, USA). Group 7: Silica coating with 30 mm SiO2 particles using an intra-oral sandblaster (3M ESPE, Germany) from a distance of 10 mm at a pressure of 2.5 bar for 4 s followed by application of the corresponding silane and bonding agents
  63. 63. Repair resin composite application • An additional 160 PMMA retention base were prepared and use for the resin composite application procedure • Mould 2 was placed onto the surface of conditioned amalgam specimen • Pack nanohybrid composite against the amalgam in 2 mm increment • Polymerized with light for 40 s Tuesday, August 13, 13
  64. 64. journal of dentistry 40 (2012) 15–21 Fig. 2 – Custom made retention base (Mould 2) positioned over Mould 1 containing the surface conditioned amalgam specimen surface conditioned amalgam specimen. 2.4. Tuesday, August 13, 13 Tensile testing The PMMA moulds retaining the amalgam–resin composite specimens were mounted on a universal testing machine (Lloyd Instruments Ltd. Model LR5K, Hampshire, UK) fitted with a 1 kN load cell, travelling at a crosshead speed of 0.5 mm/min. A tensile force was applied until failure occurred. The data were subjected to statistical analysis using a Resin composite packed into Mould 2 and packed Fig. 3 – one-way analysis of variance and post hoc Tukey’s test. against surface conditioned amalgam specimen in Fig. 3 – Resin composit against surface conditi underlying Mould 1. Am Mould 1. was defined as a fractu and cohesive failures. The failed surfaces specimens from each te dimensional profilomet profiles at the failed su value (Ra-value) of amalg following failure was d profilometry (ProScan-20 UK). Scanning was con
  65. 65. • store for 24 hrs at room temperature • tensile stress testing using universal testing machine(Lloyd instruments Ltd.) fitted with a 1 kN load cell , travelling at a crosshead speed of 0.5 mm/min • Apply force until failure occurred • Data analysis using one-way analysis of variance and post hoc Tukey’s test Tuesday, August 13, 13
  66. 66. Failure analysis • The surfaces of three randomly specimen from each group were examined under SEM • Investigate the surface morphology of the failed surfaces • Failures were classified as adhesives , cohesives or mixes Tuesday, August 13, 13
  67. 67. Failure analysis • Adhesive failure a complete debonding of the adhesive system from the treated amalgam surface • Cohesive failure was defined as a fracture that occurred in the resin composite and showed remnants of bonding agent or resin composite on both sides • Mixed failure defined as a fracture that showed evidence of adhesive and cohesive failure Tuesday, August 13, 13
  68. 68. Result • Bond strength • control group = 0 (no adhesion) • Sandblasting and alloy primer and Panavia 21 resulted in significantly higher bond strength values than other Tuesday, August 13, 13
  69. 69. bonding agent or resin composite on both sides. Mixed failure use of Alloy primer and Panavia 21 resulted in significantly Table 2 – Comparison of mean tensile bond strengths (TBS) and surface roughness values between repair protocols. Surface conditioning method Group Group Group Group Group Group Group 1 2 3 4 5 6 7 Alumina sandblasting + Alloy Primer + Panavia 21 Alumina sandblasting + Amalgambond Plus Alumina sandblasting + All Bond 3 Diamond bur + Alloy Primer + Panavia 21 Diamond bur + Amalgambond Plus Diamond bur + All Bond 3 Silica coating (CoJet-system) TBS (SD) [MPa] 5.13 2.51 2.42 3.42 3.40 1.34 3.72 (0.96) (2.73) (0.76) (0.82) (1.68) (0.71) (1.00) 95% confidence intervals (MPa) 5.71–4.58 3.72–1.27 2.87–1.99 3.78–3.09 4.06–2.75 1.60–1.10 4.24–3.22 Statistical groupings d c a,b b,c b,c a b,c Ra-value (mm) 4.76 3.58 2.35 16.56 16.03 13.46 1.95 Lower case letters indicate statistically homogeneous groups. If two data sets share the same letter, they do not differ to a statistically significant degree. All bond3 present lower bond strength compared to other conditioning methods where aluminar sand blasting was used No significant difference between the bond strength values of Cojet system , diamond-panavia system or diamond bur-amalgabond plus Tuesday, August 13, 13
  70. 70. bonding agent or resin composite on both sides. Mixed failure use of Alloy primer and Panavia 21 resulted in significantly Table 2 – Comparison of mean tensile bond strengths (TBS) and surface roughness values between repair protocols. Surface conditioning method Group Group Group Group Group Group Group 1 2 3 4 5 6 7 Alumina sandblasting + Alloy Primer + Panavia 21 Alumina sandblasting + Amalgambond Plus Alumina sandblasting + All Bond 3 Diamond bur + Alloy Primer + Panavia 21 Diamond bur + Amalgambond Plus Diamond bur + All Bond 3 Silica coating (CoJet-system) TBS (SD) [MPa] 5.13 2.51 2.42 3.42 3.40 1.34 3.72 (0.96) (2.73) (0.76) (0.82) (1.68) (0.71) (1.00) 95% confidence intervals (MPa) 5.71–4.58 3.72–1.27 2.87–1.99 3.78–3.09 4.06–2.75 1.60–1.10 4.24–3.22 Statistical groupings d c a,b b,c b,c a b,c Ra-value (mm) 4.76 3.58 2.35 16.56 16.03 13.46 1.95 Lower case letters indicate statistically homogeneous groups. If two data sets share the same letter, they do not differ to a statistically significant degree. All bond3 present lower bond strength compared to other conditioning methods where aluminar sand blasting was used No significant difference between the bond strength values of Cojet system , diamond-panavia system or diamond bur-amalgabond plus Tuesday, August 13, 13
  71. 71. bonding agent or resin composite on both sides. Mixed failure use of Alloy primer and Panavia 21 resulted in significantly Table 2 – Comparison of mean tensile bond strengths (TBS) and surface roughness values between repair protocols. Surface conditioning method Group Group Group Group Group Group Group 1 2 3 4 5 6 7 Alumina sandblasting + Alloy Primer + Panavia 21 Alumina sandblasting + Amalgambond Plus Alumina sandblasting + All Bond 3 Diamond bur + Alloy Primer + Panavia 21 Diamond bur + Amalgambond Plus Diamond bur + All Bond 3 Silica coating (CoJet-system) TBS (SD) [MPa] 5.13 2.51 2.42 3.42 3.40 1.34 3.72 (0.96) (2.73) (0.76) (0.82) (1.68) (0.71) (1.00) 95% confidence intervals (MPa) 5.71–4.58 3.72–1.27 2.87–1.99 3.78–3.09 4.06–2.75 1.60–1.10 4.24–3.22 Statistical groupings d c a,b b,c b,c a b,c Ra-value (mm) 4.76 3.58 2.35 16.56 16.03 13.46 1.95 Lower case letters indicate statistically homogeneous groups. If two data sets share the same letter, they do not differ to a statistically significant degree. All bond3 present lower bond strength compared to other conditioning methods where aluminar sand blasting was used No significant difference between the bond strength values of Cojet system , diamond-panavia system or diamond bur-amalgabond plus Tuesday, August 13, 13
  72. 72. bonding agent or resin composite on both sides. Mixed failure use of Alloy primer and Panavia 21 resulted in significantly Table 2 – Comparison of mean tensile bond strengths (TBS) and surface roughness values between repair protocols. Surface conditioning method Group Group Group Group Group Group Group 1 2 3 4 5 6 7 Alumina sandblasting + Alloy Primer + Panavia 21 Alumina sandblasting + Amalgambond Plus Alumina sandblasting + All Bond 3 Diamond bur + Alloy Primer + Panavia 21 Diamond bur + Amalgambond Plus Diamond bur + All Bond 3 Silica coating (CoJet-system) TBS (SD) [MPa] 5.13 2.51 2.42 3.42 3.40 1.34 3.72 (0.96) (2.73) (0.76) (0.82) (1.68) (0.71) (1.00) 95% confidence intervals (MPa) 5.71–4.58 3.72–1.27 2.87–1.99 3.78–3.09 4.06–2.75 1.60–1.10 4.24–3.22 Statistical groupings d c a,b b,c b,c a b,c Ra-value (mm) 4.76 3.58 2.35 16.56 16.03 13.46 1.95 Lower case letters indicate statistically homogeneous groups. If two data sets share the same letter, they do not differ to a statistically significant degree. All bond3 present lower bond strength compared to other conditioning methods where aluminar sand blasting was used No significant difference between the bond strength values of Cojet system , diamond-panavia system or diamond bur-amalgabond plus Tuesday, August 13, 13
  73. 73. bonding agent or resin composite on both sides. Mixed failure use of Alloy primer and Panavia 21 resulted in significantly Table 2 – Comparison of mean tensile bond strengths (TBS) and surface roughness values between repair protocols. Surface conditioning method Group Group Group Group Group Group Group 1 2 3 4 5 6 7 Alumina sandblasting + Alloy Primer + Panavia 21 Alumina sandblasting + Amalgambond Plus Alumina sandblasting + All Bond 3 Diamond bur + Alloy Primer + Panavia 21 Diamond bur + Amalgambond Plus Diamond bur + All Bond 3 Silica coating (CoJet-system) TBS (SD) [MPa] 5.13 2.51 2.42 3.42 3.40 1.34 3.72 (0.96) (2.73) (0.76) (0.82) (1.68) (0.71) (1.00) 95% confidence intervals (MPa) 5.71–4.58 3.72–1.27 2.87–1.99 3.78–3.09 4.06–2.75 1.60–1.10 4.24–3.22 Statistical groupings d c a,b b,c b,c a b,c Ra-value (mm) 4.76 3.58 2.35 16.56 16.03 13.46 1.95 Lower case letters indicate statistically homogeneous groups. If two data sets share the same letter, they do not differ to a statistically significant degree. All bond3 present lower bond strength compared to other conditioning methods where aluminar sand blasting was used No significant difference between the bond strength values of Cojet system , diamond-panavia system or diamond bur-amalgabond plus Tuesday, August 13, 13
  74. 74. Failure analysis • All specimen failed adhesively • The roughness of the specimen prepared by alumina sandblast was less than the diamond bur , Cojet silicatization produced the lowest surface roughness Tuesday, August 13, 13
  75. 75. Failure analysis journal of dentistry 40 (2012) 15–21 Tuesday, August 13, 13 Fig. 4 – SEM images of amalgam surfaces treated mechanically with (a) alumina sandblasting, (b) diamond bur and (c) 19
  76. 76. Discussion • Repairing an amalgam restored tooth exhibiting signs of single or multiple cusps fracture can result in extend longevity of the existing restoration • In the case of cusp fracture it is often aesthetically favourable to veneer the amalgam with tooth-coloured material Tuesday, August 13, 13
  77. 77. • Important factor in the quality of amalgam repair is the interfacial bond between the joined surfaces • Previous studies suggested that shear bond strength testing has limitation • The basic selection of the adhesive repair system used in the current study was their demonstrated ability to bond to metal • In contrast to previous study , the finding of current study indicated that surface roughness of the amalgam substrate appears to have significant influence on its repair bond strength Tuesday, August 13, 13
  78. 78. • Alumina sandblasting and silicatization cause micro retention feature • Diamond bur yields “macro” and “micro” retentive features • Without use of adhesive , greater repair strength may be anticipated from the substrates yielding macro retentive feature Tuesday, August 13, 13
  79. 79. • • due to better infiltration and improved physical interlocking • Alumina sandblasting and silicatization remove large surface asperities and provide a more homogenous surface with major defects and stress concentration removed • Tuesday, August 13, 13 With the use of adhesive , a better surface wetting was found occur with the micro-retentive amalgam surface high degree of roughening(13.5-16.6um) induced by tx with diamond bur is likely to induce surface defect and area of concentration , deep asperities which adhesive may not fully infiltrate
  80. 80. • Previous studies have highlighted higher interfacial bond strengths between amalgam and resin composite where low surface roughness values were induced • In this study a lower surface roughness induced by alumina sandblasting in combination with Panavia 21 adhesive system resulted in a significantly higher tensile bond strength compared with the Panavia 21 but prepared with a diamond bur • This may suggest that improved surface homogenity implicit in the removal of large surface defects associated with alumina sandblasting improved adhesive bond to formed between 2 surfaces Tuesday, August 13, 13
  81. 81. Conclusion • • 2. The combination of alumina sandblasting of the amalgam surface followed by the application of the Panavia 21 adhesive system exhibited significantly higher tensile bond strengths than other repair protocols tested • Tuesday, August 13, 13 1. The tensile bond strengths of resin composite to amalgam varied with the degree of amalgam surface roughness and the type of conditioning technique employed. 3. Interfacial failure between amalgam and resin composite was of adhesive nature, irrespective of the repair protocol employed.
  82. 82. • ขอบพระคุณ อาจารย์ชัยศรี ธัญพิทยากุล Tuesday, August 13, 13

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