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. 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. 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. 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. 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
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
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. 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. •
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. •
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
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. Result
• All the groups exhibited microleakage
between the amalgam-resin interface and
the tooth-resin interface
Tuesday, August 13, 13
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
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. Alternative options for defective
amalgam restoration
• Rapairing
• Sealing
• Refurbishing
Tuesday, August 13, 13
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. 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. Important factor
• Interfacial bond between the joined
surfaces
• clean surfaces , roughening amalgam ,
adhesive for metallic
Tuesday, August 13, 13
45. Microleakage test
• useful methods for evaluating sealing
performance of adhesive systems
• image analysis to obtain quantitative results
Tuesday, August 13, 13
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. 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
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. 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. 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. 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. • 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. 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
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. Null Hypothesis
• There was no statistical difference in repair
bond strengths between the various repair
protocols
Tuesday, August 13, 13
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. •
•
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
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. 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. 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. 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. • 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. •
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. • 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. •
•
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. •
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. 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.