Cooled composites inserts /certified fixed orthodontic courses by Indian dental academy

INDIAN DENTAL ACADEMY
Leader in Continuing Dental Education
www.indiandentalacademy.com

Introduction
 Resin composites……
 Advantage
Excellent esthetics
Relatively low thermal conductivity
Preservation of tooth structure
 Disadvantage
Polymerization shrinkage (2.6 – 7.1)
↓ wear resistance
Difficulty in obtaining proximal contacts
Varying thermal expansion

Stress induced Disruption in
contraction force marginal integrity
rb ate
ce Passage of fluids,ions
Exa
Expansion
(microleakage)

Hypersensitivity ,
Secondary caries

Failure of restoration

To overcome shrinkage……
Acid etching – effective method
Indirect restoration
‘C’ factor modification
↑filler content – limitation
Nanofillers
Expanded co-polymers
↓ setting stress – soft start polymerization
Inserts - ↑ filler resin ratio

Curing rate & degree of cure ∞ temperature

Aim
To evaluate sealing ability of
class V composite resin restoration
using cooled prepolymerized
composite inserts & comparing with
room temperature resin inserts &
without any inserts.

Materials & Methods

Preparation of inserts

Teeth stored in
saline www.indiandentalacademy.com

Room temperature
Cooled inserts
inserts

Standardized class V cavity preparation

Acid etching & Bonding agent application

Group A www.indiandentalacademy.com Group C
Group B

Immersion of teeth in Methylene blue solution
for 12 hrs

Making of
sections


Intra oral camera with software for microleakage
evaluation

Group A www.indiandentalacademy.com Group C
Group B

Scoring criteria for microleakage
♥ Score 0 – no leakage
♥ Score 1 – dye penetration within 1/3 of cavity wall

♥ Score 2 – dye penetration within 2/3 of cavity wall

♥ Score 3 – dye penetration within last 1/3 of cavity

wall upto the axial wall.
♥ Score 4 – dye penetration spreading along the axial

wall
Evaluation of penetration leakage
Scored as present or absent

Statistical analysis
Mann Whitney’s ‘U’ test for group wise comparison

Kruskal Walli’s test for leakage between inserts &

resin composite

Mann Whitney’s ‘U’ test for comparing occlusal &

gingival microleakage values

Level of significance – 5%

Occlusal [Enamel] microleakage scores
Groups Leakage score
0 1 2 3 4
Group A (28) 1 6 4 6 11
Group B (29) 16 6 2 1 4
Group C (32) 28 2 2 0 0

Gingival [Dentin] microleakage scores
Groups Leakage score
0 1 2 3 4
Group A (28) 2 5 4 3 14
Group B (29) 11 5 7 4 2
Group C (32) www.indiandentalacademy.com
20 7 3 2 0

Results
In occlusal margin
Group A vs Group B – no significant difference (P=0.85)
Group B vs Group C – significant difference (P=0.0017)
Group A vs Group C – significant difference (P=0.0038)
In gingival margin
Group A vs Group B – no significant difference (P=0.72)
Group B vs Group C – significant difference (P=0.0011)
Group A vs Group C – significant difference (P=0.0026)

Gingival > occlusal (P=0.0065)
No leakage between insert & composite resin

Discussion
۩ Limitation of filler loading (70 -75%)
۩ Use of inserts……
۩ ↑ filler resin ratio
۩ ↑ wear resistance
۩ Volumetric thermal expansion = 0
۩ ↓ failure fatigue of posterior restoration

β Quartz inserts
In 1993 Tjan et al – do not significantly
improve the marginal integrity

Disadvantage……
Resin – insert interface
Possible contamination during
manipulation
Failed to reduce stress generated by
contraction force

Composite inserts
Improved resin – insert interface
Size - ↓ light transmission – improper curing

Small room temperature inserts
Curing phase reduction – not enough to
significantly ↓ leakage

Adhesion to enamel better than to dentin or
cementum www.indiandentalacademy.com

Cooled inserts

Hybrid layer remained intact
Thermal expansion of cooled inserts
Curing rate & degree of cure ↓ when setting
reaction occurs at lower temperature
Pregel period could be longer
Shrinkage vectors
Thermal effect of curing light

Conclusion
Under the condition of this study,
Small prepolymerized composite inserts
have improved resin – insert interface
Cooled prepolymerized inserts showed
improved sealing ability of class V
composite restoration with respect to room
temperature inserts & bulk insertion
technique

Cooled composites inserts /certified fixed orthodontic courses by Indian dental academy

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Cooled composites inserts /certified fixed orthodontic courses by Indian dental academy