1. Operative Dentistry
Microleakage Resistance of Minimally Invasive Class I Flowable Composite Restorations

2. INTRODUCTION
Minimally invasive flowable composite Class I restorations
Esthetics
Less removal of sound tooth structure than amalgam
Adhesion to enamel reduce the risk of leakage and secondary caries

3. INTRODUCTION Resinous composite  Polymerization shrinkage
Loss of adhesion
Microgap formation
Microleakage of bacteria and their toxin product
Postoperative tooth sensitivity
Secondary caries
Pulp disease
Marginal staining
Restoration failure

4. Polymerization shrinkage
Flowable composites
Lower filler concentrations
Modified resin formulations
Low moduli of elasticity
Low vicosity : easier to place in conservative tooth preparations
Poor mechanical properties
Decrease long-term stability
Reduce polymerization shrinkage  Reduce microleakage (?)
Filler
Elastic modulus
Vicosity
Stress relaxation
Polymerization shrinkage
High ↑ ↓
Low
↓ (?)

5. Mid-1990s : Flowable composites
Lower filler concentrations
Modified resin formulations
Low moduli of elasticity
Low vicosity : easier to place in conservative tooth preparations
Poor mechanical properties
Decrese long-term stability
Reduce polymerization shrinkage  Reduce microleakage (?)
Mid-1990s : Flowable composites

6. INTRODUCTION
Purpose : to compare microleakage resistance of - Flowable composites - Microhybrid composite placed as minimally invasive occlusal restoration

7. METHODS AND MATERIALS
Tooth preparation 100 molars were stored in water at 37⁰C Mounted in acrylic resin block Preparation (3 mm in length, 0.6 mm in width, 1.5 mm in depth)

8. Restoration
Bonilla & others: Flowable composite microleakage

9. Microleakage Assessment
Restoration Stored in water 37⁰C (14days) Thermal cycling(5-50⁰C, 1000cycles, 20 sec) Coat with 2 layers of a clear nail polish

10. Submerged in 50% solution of silver nitrate (60min) Rinse with water, place in photo developer Exposed under a 150-W floodlamp (30 min) Embeded the specimen

11. Sectioned faciolingually through reference mark Re-exposed to the 150-W floodlamp (5min) Measured the distance of stain penetration in millimeters

13. Analysis
Mean microleakage means and associate standard deviations were calculated for each material group and plotted.
Two-way analysis of variance
The Tukey multiple comparisons test

14. RESULT

15. RESULT

16. RESULT

17. RESULT
Defects of bubbles were seen within the bulk restorative materials in 56% of the 200 sections
Mostly, these bubbles were very small, approximately 50 to 100 µm in diameter, but three larger voids were seen.
They often appeared as white spots on the sectioned specimens because they tended to be filled with sectioning debris.

18. RESULT Groups Bubble and void HX – OB and UF- UB No R2 – OB and FI –B1
6 Specimens
FF –SB
5 Specimens
AF-SB and PF-PQ
4 Specimens
VF-TQ and GD-GB
3 Specimens
HM-EX
2 Specimens

19. RESULT
Because of the unexpected identification of tiny bubbles and larger voids
The flowable composites were expressed directly onto glass slabs, polymerized, sectioned and examined as above
Tiny bubbles were revealed, but larger voids were absent.

20. DISCUSSION
In the present in vitro study, the inorganic compound silver nitrate was selected.

21. DISCUSSION
Multiple factors may influence the microleakage resistance of minimally invasive composite restorations polymerization shrinkage - elastic modulus - cavity configuration - amounts of exposed enamel and dentin - restoratives procedure

22. DISCUSSION
C factor directly proportional to stress levels and probability of separation of the composite from the wall of the tooth preparation.
Bonded surface
Unbonded surface
C factor =

23. Figure 2. Bar graph of microleakage of composite and bonding agent groups in millimeters. Means and standard deviations are displayed. Flowable composite groups are illustrated by black bars; the control microhybrid composite group is illustrated by a gray bar. Statistically similar groups are linked by horizontal lines (p.0.05).

24. DISCUSSION
From this study, flowable composite groups (R2-OB) recorded five times more microleakage than the control microhybrid composite group (HX-OB).
Caused by conservative cavity preparations tended to be cut along or obliquely to rods , exacerbating the lesser etching ability of the self-etching adhesives.
-- From this study, flowable composite groups (R2-OB) recorded five times more microleakage than the control microhybrid composite group (HX-OB)
ซึ้งผลิตมาจากบริษัทเดียวกัน ได้ผลดังนี้เพราะ… --

25. Figure 3. Bar graph of microleakage of measurement site locations in millimeters. Means and standard deviations are displayed. Statistically similar groups are linked by horizontal lines (p.0.05).

26. DISCUSSION
Preheating composite resin with appropriate devices such as Calset (AdDent Inc, Danbury,
CT, USA) has been advocated as a method to reduce paste viscosity, to improve internal adaptation and marginal adaptation, and to shorten curing times.
with-standard-composite-compule-tray.html

27. DISCUSSION
A strong positive correlation between temperature and monomer conversion has also been demonstrated in vitro. However, in vitro testing of adaptation and microleakage resistance of pre-heated resins has produced mixed results.

28. DISCUSSION
Flowable composites inherently contain proportionally more resin and less filler than conventional composites. This reduces
their viscosity and enhances their flowability. However, this makes them more difficult to pack into cavity preparations and increases the technical difficulty of removing microbubbles during the manufacturing process.

29. DISCUSSION
Long time ago , Anusavice identified that both viscosity and void concentration influence rheology, or flow.
Preparation design in this study, using a standard fissurotomy bur created relatively narrow and deep, having an unfavorable C-factor.

30. DISCUSSION
Another approach study on ultraconservative cariostatic sealed restoration used 45°to 60° enamel bevels at least 1 mm wide but did not excavate carious dentin which created highly favorable C-factor , an autocured highly-filled hybrid composite was placed and shaped, then covered with bonded fissure sealants.

31. DISCUSSION
These are capable of conserving tooth structure, preventing recurrent caries, and extending restoration survival.
That data also indirectly suggested that both the use of flowable composites and narrow deep fissurotomy preparations must be
critically examined, or at least compared with other preparation designs.

32. CONCLUSION
Microleakage varied substantially, among the material groups tested.
The control group, a conventional microhybrid composite material used with its manufacturer’s recommended bonding agent, leaked significantly less than a wide variety of flowable composites used with their manufacturers’ recommended bonding agents.

33. CONCLUSION
Microcroleakage varied very slightly among measurement site locations.
Tiny microbubbles were seen within many of the flowable composite specimens, as were a few voids.