Different materials used in denture base reinforcement in case of single denture .pptx

1. Different materials used in
denture base reinforcement
in case of single denture
Presented by: Mai Mohamed Mohamed

2. Outline
- Intro
- Single Denture Problems
- Reinforced base materials Classification
- Carbon Fibers
- Glass Fibers
- Factors Affecting Fiber Reinforcement
- Case Reports
- Conclusion
- References

3. Intro: what’s single denture?
• A single complete denture is a complete denture that
occludes against some or all of the natural teeth, a fixed
restoration, or a previously constructed removable partial
denture or a complete denture.

4. • “Perpetual Preservation Of That What Remains Rather
Than Meticulous Replacement Of What Has Been Lost.”

5. Problems of Single Denture?
• Excessive forces from natural dentition or fixed
dentures >>> Loss of denture stability >
undesirable movement of the denture> fracture
due to heavy forces & excessive ridge resorption.
• 2. Disruption of stability and retention, as a result
of the inability to create a balanced occlusion, due
to the malposition of natural teeth (e.g., tilting,
overeruption,rotation).
• 3. Occlusal plane disharmony.

6. Denture Base Materials
- Heat polymerized resin dentures are the
dominant material for the fabrication of denture
bases for its acceptable appearance
But, its poor mechanical properties along with
heavy occlusal loads made it’s very common to
fracrure so the need for an alternative material
or a chemical modification or use of different
denture base material reinforcements of PMMA
was raised.

7. Denture Base Material
- Metal bases are valuable alternative for
denture bases opposing natural dentition for
strength & fracture resistance >> high
mechanical properties
-Poor Esthetics >> low patient satisfication
-Weight could also be a problem
-Properly designed metal denture bases aid in
conserving the supporting tissues of the
denture bearing areas.

8. *Metal Mesh
-Metal mesh is commercially available in both stainles steel and gold plated metal.
They have a thickness of 0.4mm.
Reinforcement Using Stainless Steel Mesh, Glass
Fibers, and Polyethylene

9. Reinforcement using glass fiber and polyethyleneprepreg

10. -Polyethylene fibers show better impact strength followed
by glass fibers and stainless steel mesh. By using
preimpregnated glass and polyethylene fibers in woven form,
(prepregs) the impact strength of the denture bases can
beincreased effectively.

11. Reinforced base materials could be used
to prevent denture fractures.

12. Denture base reinforcing materials
Non Metals Metals
1. Rubber reinforced PMMA
2. High impact resins
3. Fiber reinforced resins
i. Carbon/ Graphite fiber reinforced
ii. Aramid fiber reinforced
iii. Polyethylene fiber reinforced
iv. Highly drawn linear polyethylene fibers
v. Polypropylene fiber reinforced
vi. Polyamide fiber
vii. Glass fibres
viii. E Glass fibers (Electrical grade)
4. Hypoallergenic resins
5. Resins with modifies chemical structure
6. Thermoplastic resins
7. Nanomaterials
i. Nanofillersrconia
ii. Nanofibers
1. Metal fiber reinforced resins
2. Metal inserts
i. Stainless Steel wires
ii. Brass wires
3. Nanofillers
i. Silver
ii. Copper
iii. Titanium (TiO2)
iv. Gold
v. Platinum
vi. Palladium

13. Rubber reinforced PMMA
- The resin matrix is filled with a rubbery particle butadiene
styrene rubber.
-↑ impact strength
-↑fracture toughness and ultimate elongation in comparison
with conventional PMMA.( Flexible)

14. High Impact Resins
- Rubber reinforced (butadiene-styrene
polymethyl methacrylate) particles grafted to
MMA for improved bond with PMMA.
↑↑impact strength & fatigue properties
- indicated for patients who drop their dentures
repeatedly e.g. parkinson disease

15. Fiber Reinforced Resins
- Fibers are used to improve the flexural, impact strength as
well as fatigue resistance of the resin
-The mechanical behaviour of the material is affected by the
orientation of the fiber: Parallel arrangement -> optimum
reinforcement
Fiber weave> TFR
Fiber bundels at the weak areas of the dentured >PFR

16. The denture base can be reinforced by
fibers in two ways:
Total Fiber Reinforcement
• The entire denture base can
be reinforced .
• During denture fabrication
Partial Fiber Reinforcement
• The reinforcement can be
accurately placed on weak
areas of the denture
• - During Denture Repair

18. Factors that affect the strength of fiber
reinforced materials
• Adhesion between fibers and polymer
• Impregnation of the fibers with the polymer
• Concentration of the fiber
• Composition of resin,
• Fiber form, fraction, position & orintation

19. Carbon Fibers
- Carbon fibers are inserted during
packing.
-↑elastic properties & ↑fatigue resistance
-Silanation of the fibers improve the
strength
Disadvantages: -potential toxicity -poor
esthetics -polishing problems -difficult
handling.

20. Aramid Fibers
• Aramid fibers are aromatic polyamide fibers, generally
called Kevlar fibers
• - have superior wettability -no need for a coupling agent.
• ↑fracture resistance but↓ the hardness with increasing
fiber concentration.
• Their yellow color and exposure on the surface of the
denture makes the denture inconvenient for patients and
creates polishing problems for the technician

21. Nylon Fibers
• Nylon fibers are polyamide fibers .
• The main advantage of nylon lies in its resistance to
shock and repeated stresses.
• But, water absorption affects its mechanical properties.

22. Polyethylene Fibers
- Highly drawn linear polyethylene (HDLPE)
>> high stiffness and strength.
- Have notch insensitivity, coherence & resistance to crack
propagation during bending and impact.
- parallel continuous high density linear polyethylene
fibers>> fiber orientation

23. Polyethylene Fibers
Have neutral color >> better Esthetics
- Known biocompatibility.
They show significant reduction in water sorption and
dimensional changes Due to hydrophobic nature of the
fibers.
- Low density & ductile. -Excellent polishing characteristics
using standard dental techniques.

24. • Polyethene and polypropylene fibers have been used
because of their better esthetic characteristics than other
fibers. However, these fibers require a surface treatment
(eg. Plasma etching) to increase the impact strength of
PMMA significantly

27. Glass Fibers
• - The predominant reinforcement for a
polymer matrix due to their high
mechanical properties, low susceptibility to
moisture absorption, resistance to
chemicals, thermal stability and high
melting point.
• -Translucency of glass fibers provides for
aesthetically pleasing dentures.

28. Glass Fibers
• - The reinforcing effect of the fibers is based on stress
transfer from the polymer matrix to fibers and also the
behavior of individual fibers acting as a crack stopper
• ↑fatigue resistance, impact strength, and flexural strength.
• Modulus of elasticity of glass fibers is very high>> most of
the stresses are received by them without deformation.

29. Disadvantages of Glass Fibers
- Glass fibres are generally added to the polymer by hand;however, problems
can arise with the lateral spreading of fibres in the polymer matrix as acrylic
resin is pressed inthe mould causing an inhomogenous distribution throughout.
- Poor wetting of fibres within the acrylic resin and polymerization shrinkage of
the PMMA destroys the layer of resin on the surface of the fibres and decreases
the bond between the fibres and the polymer.
- Improper impregnation of polymer matrix into the fiber bundle cause reduction
in transverse strength of denture base polymer and a lack of the adsorbed
monomer liquid in the fiber bundle before polymerization cause a void space.

30. Hypoallergenic Resins
• - Addition of hydroxyapatite fillers increases
fracture toughness.
• Addition of Al2O3 fillers increases the flexural
strength &thermal diffusivity that could lead to more
patient satisfaction.

31. Metal Inserts
- Metals can be added in the form of wires, plates or fillers.
- Metal inserts in the form of wires, meshes, and plates are
still incorporated into dentures in an attempt to reinforce
areas that are liable to fracture.
-Often, a metal insert is a stress concentration area that
tends to weaken rather than strengthen the denture base.
- The effect of metal strengtheners on the fatigue resistance
of dental appliances is minor.

32. Reinforcement with Metal Bases
- Gold or cobalt-chrome-
molybdenum or cobalt chrome
alloy dentures have superior
physical and mechanical
properties.
- Reducing fungal growth
- Hight Strength and high
resistance to fatigue and are less
likely to break under normal
conditions

33. Reinforcment of Metal bases
Metal bases facilitate fabrication of stable narrow dentures that are
designed to avoid contact with disrupting muscle forces.
- Patients perceive natural feeling from thin base which may also
contribute to additional denture stability.
- Metal bases are considered dimensionally stable compared to all-
plastic based dentures both during fabrication and overtim
Still it’s expensive. - Prone to corrosion. -Unaesthetic. -Poor
adhesion to denture base resin.

34. • A nanomaterial is an object, which at least one of its dimensions is at the
nanometer scale (approximately 1 to 100 nm). Nanomaterials are
categorized according to dimension – those with all 3 dimensions less than
100 nm [nanoparticles (Nps)]; those that have 2 dimensions less than 100
nm (nanotubes, nanofibers, and nanowires); and those that have one
dimension less than 100 nm (thin films, layers, and coatings).

35. NanoFiller
• Size, shape, surface area, concentration, and dispersion
of nanofillers into resin matrix all affect its mechanical
properties. Alumina NPs, zirconia (ZrO2) NPs, titaniam
(TiO2) NPs, silver NPs, gold NPs, Pt NPs, HA NPs, SiO2
NPs etc are introduced to improve the mechanical
properties of PMMA.

37. Self Reinforcment
-The concept of self-reinforcement of polymers is based on the idea of a fibrous
material which is chemically identical to the matrix holding the fibers in place.
-The reinforcement of PMMA with PMMA fibers of improved mechanical
properties compared to the bulk resin.
-High strength, high ductility PMMA fibers embedded in a matrix of PMMA.
The fibers were processed to impart large amounts of molecular orientation by
thermo molecular processing (e.g. fiber spinning or drawing).
-The mechanical properties of a unidirectional continuous form of the composite
have shown to possess greater tensile properties, ductility, fracture toughness
and fatigue strength compared with bulk PMMA.

38. References
- Meng TR, Latta MA. Physical Properties of Four Acrylic Denture Base Resisns. J Contemp
Dent Pract. 2005;6(4):93–100.
- Alla RK, Sajjan S, Alluri VR, Ginjupalli K, Upadhya N. Influence of Fiber Reinforcement on the
Properties of Denture Base Resins. J Biomater Nanobiotechnol. 2013;4(1):91–7.
- Denture base materials: From past to future. RenuTandon, Saurabh Gupta, Samarth Kumar
Agarwal IndianJournal of Dental Sciences. Vol .2, Issue 2 March 2010.
- Glass fiber reinforcement in repaired acrylic resinremovable dentures: Preliminary results of a
clinicalstudy Pekka K. Vallitiu. Quintessence InternationalVolume 28, Number 1/1997
- Mechanical and thermal properties of polyamide versus reinforced PMMA denture base
materials Koray Soygunet alJ Adv Prosthodont 2013;5:153-60

39. Thank you!