1. 1
Preventive dental
materials
Preventive dental
Preventive dental
materials
materials

2. 2
Why are they used?
• To prevent injury or disease.
• Three classes of materials are
involved
– Fluoride gels
– Pit and fissure sealants
– Mouth protectors

3. 3
Fluoride
• Gels: acidulated sodium fluoride gels
contain 2% sodium fluoride (or more) +
hydrogen fluoride + phosphoric acid.
Fluoride ion concentration 1.22-1.32%.
Stannous fluoride maybe used too.
• Rinses: sodium fluoride or stannous
fluoride
• Varnishes
* Some products have pH of 6-8 to prevent
acid etching of restorations

4. 4
Rinse
Varnish
Gel

5. 5
Properties
• Help to reduce smooth surface cries
• Effectiveness depends on method of
application and frequency and
duration.
• A gel should be viscous enough for
ease of handling but fluid enough to
flow all around teeth

6. 6
Manipulation
Fluoride gel in trays: teeth clean and dry,
patient should bite for 4 minutes and not
rinse for 30 minutes

7. 7
Pit and fissure sealants
• To prevent pit and
fissure caries
• Pits and fissures are
enamel faults,
inaccessible to
cleaning using tooth
brushes
• Another method to
seal fissures is using
air abrasion then
flowable composite.

8. 8
Composition and reaction
• Similar composition to resin composite but
more fluid.
• MOSTLY ACTIVATED BY VISIBLE LIGHT
• 2 component systems are activated by
peroxide initiator and amine activator
• Components:
– Bis-GMA
– UDMA

9. 9
Examples

10. 10
Properties
• Physical and mechanical properties
depend on the product.
• Bonding is mechanical by acid etching
done to:
– Clean the surface
– Improve wettability
– Create a rough surface

11. 11
Properties
• Sealant penetration maybe difficult due
to:
– Air entrapment
– Food debris accumulation
• Penetration of sealant into fissure
depends on:
– Penetration coefficient of sealant:
• Surface tension
• Viscosity of sealant
• Contact angle of sealant with enamel
– Configuration of fissure (length, diameter)

12. 12
• For sealants to be effective they
have to be retained.
• Reviews are important to replace
deficient sealants
• If caries exists under sealants,
studies showed that the number of
bacteria is low.

13. 13
When a sealant is not
used
• Uncooperative patients
• If molars are caries free for a long
time
• If there are no pits an d fissures

14. 14
Application

15. 15
Mouth protectors

16. 16
General points
• Made from polymers
• Formed by heat to fit over teeth
• Used to protect from injury or as
vehicle to apply fluoride or bleaching
material

17. 17

18. 18
Types and composition
• Stock
• Mouth formed
• Custom made: preferred, due to:
– Better comfort
– Lack of bad odor or taste
– Minimal impaired speech
– Durability
– But more expensive than other types

19. 19
Composition
• Custom made: in sheets 1.6-3 mm
thick
– Thermoplastic polymer (poly-vinyl
acetate-polyethylene polymer) or called
ethylene vinyl acetate (EVA)
– Other products: rubber latex
– Polyurethane
– Vinyl plastisol.

20. 20
Types
Custom made
Mouth formed
Stock

21. 21
Properties
• ADA specifications consider physical,
mechanical properties
• EVA properties before and after
insertion into oral cavity are
different. Inside the mouth, they
become more flexible, better impact
strength, but less tensile strength

22. 22
Compared to other
products
• Polyurethanes: higher strength,
hardness, higher water sorption,
need higher processing temperatures
• Plastisol and rubber latex have
slightly lower strength and hardness
compared to EVA but are difficult to
process

23. 23
Complaints
• Gagging
• Discomfort
• Irritation
• Bad taste
* Not common if mouth guard is made
properly.

24. 24
Continue,
• Thicker mouth guard is stronger but
more uncomfortable
• A final thickness of 4 mm is
desirable over incisal edge and cusps.
Usually 2 thin sheets are used to
compensate for shrinkage

25. 25
Failures
Bite through, chewing through,
tearing

26. 26
• Parafunctional habits affect the
longevity of mouth protectors
• Deformation may occur due to
improper storage (in heat, tight
space
• Should be stored on stone model or
in a rigid container

27. 27
Fabrication
• Taking an impression
• Pouring a model
• Forming the thermoplastic material
on the model (by hand, pressure
lamination, vacuum)
• Finishing

28. 28
How is it made?
Palatal area is
not needed

29. 29
Vacuum and pressure
lamination techniques
Both are more
accurate than by hand

30. 30
Technique continue,
• Model is centered
• Sheet is heated
• Lowered onto the model
• Vacuum to fit the sheet on model
• Cooling
• If primary teeth are erupting a
spacer is placed

31. 31
Continue,
• Trimming: 3 mm above labial fold, clearance for
frenum
• Edges should be smooth by flame torching them
then smoothed with fingers
• For occlusal adjustment: occlusal surface is
heated than placed inside patients mouth in
occlusion.
• If vertical dimension is to be increased extra
layers of polymer are placed when soft then a
second layer under vacuum.

32. 32
Hand forming technique
• Sheet is softened in boiling water for
20 seconds
• Adapted by fingers on model and held
by wet towel
• Trimmed and finished

33. 33
Maintaining mouth guard
• Clean teeth
• Clean mouth guard occasionally
• Do not use abrasive
• Do not use alcohol
• Store in container provided

34. 34
References
• Dental materials, properties and
manipulation chapter 3.