5. Success of treatment with CD
Integration of oral functions +
psychological acceptance
Perception of the dentures as stationary
during function
6. ‘That quality inherent in the prosthesis
which resists the force of gravity,
adhesiveness of foods, and the forces
associated with the opening of jaws’
- GPT
The resistance of removal in a direction
opposite that of insertion
- Boucher
7. The resistance of the movement of a
denture from its basal seat, especially in
a vertical direction
- Winkler
The resistance it poses to withdrawal
from its planned position in the mouth
-Grant & Johnson
8. Atmospheric pressure
Surface tension
Viscosity of saliva
Physical retention:
area of the denture
adaptation of denture
viscosity of saliva
volume of saliva
wettability of the denture base resin
9. RETENTION
ANATOMICAL
Size of the denture
bearing area
Quality of the denture
bearing area
Parallel ridge walls
PHYSIOLOGICAL
Saliva
PHYSICAL
Adhesion
Cohesion
Interfacial surface
tension
Capillarity
Atmospheric pressure
Gravity
MECHANICAL
Undercuts
Retentive springs
Magnetic forces
Denture adhesives
Suction chambers & discs
Palatal implants
MUSCULAR
Oral musculature
Facial musculature
10. Primary retention
-physical means
-mechanical means
Secondary retention
- surrounding musculature
- shape of the denture borders &
flanges
- psychological factors
- proper instructions
12. ‘The tension or resistance to separation
possessed by the film of liquid between
two well-adapted surfaces’
- GPT
‘The resistance to separation of two
parallel surfaces that is imparted by a
film of liquid between them’
14. INTERFACIAL SURFACE TENSION
Thin layer of fluid that is present between
two parallel planes of rigid material
Ability of the fluid to wet the rigid
surrounding material
Low surface tension : maximize contact-
spread out in thin film
High surface tension : minimize its
contact – formation of beads on the
material’s surface
15. Processed denture base materials-
higher wettability
High surface tension reduced on coating
by the salivary pellicle
› Retention by virtue of the tendency of the
fluid to maximize the contact between the
denture base & mucosa
16. Capillarity
‘That quality or state, because of surface
tension causes elevation or depression of
the surface of a liquid that is in contact
with a solid’
- GPT
17. Close adaptation between denture
base & mucosa- thin film of saliva in the
space
› Retention- Capillary tube in which the liquid
seeks to increase its contact
18. Important in maxilla
If two plates with interposed fluid
immersed in the same fluid- no resistance
External borders of mandibular denture
awash in saliva
19. INTERFACIAL VISCOUS TENSION
Force holding two parallel plates
together that is due to viscosity of the
interposed liquid
20. Stefan’s law: For two parallel, circular
plates of radius (r)
that are separated by a newtonian
(incompressible) liquid of viscosity (k), &
thickness (h),
the force (F) necessary to pull the plates
apart at a velocity(V)
in a direction perpendicular to the
radius will be
F=(3/2)πkr4 V
h3
21. Viscous force viscosity of the fluid
Viscous force thickness of the medium
Viscous force opposing surface area
22. Optimal adaptation- minimal ‘h’
Maximizing denture bearing area-
maximum ‘r’
Increasing the viscosity of the medium
Slow steady displacing action-small ‘V’
effective at removing the denture than a
large ‘V’
Enhanced by ionic forces- adhesion &
cohesion
23. ‘Physical attraction of unlike molecules
for each other’
IONIC FORCES
Salivary glycoproteins
Acrylic resin
in denture
base
Surface
epithelium of the
mucous
membrane
24. Xerostomia :Adhesion between denture
base & the dry mucosa
Not very effective- mucosal abrasions &
lacerations
Ethanol free rinse with aloe or lanolin
Saliva substitute with
carboxymethylcellulose/ mammalian
mucin
Sjogren’s syndrome: 5-10mg oral
pilocarpine tds
25. Retention by adhesion with area
covered by denture
Mandibular dentures , small jaws, very
flat alveolar ridges- less adhesion
Dentures extended to limits of the health
& function of oral tissues
Preserve the alveolar height
26. ‘Physical attraction of like molecules for
each other’
Within the layer of interposed saliva &
maintains its integrity
Normal saliva not very cohesive unless
modified
High mucinous saliva- though more
cohesive, less retentive
27. Supplement retention if:
Teeth are positioned in the neutral zone
Polished surfaces of the denture are
properly shaped
Buccal & lingual flanges should be so
shaped that the musculature fits
automatically
28. Buccal flange
Buccinators tend to retain both
Tongue perfect the border seal if: lingual
surfaces of the lingual flanges slope
toward the centre of the mouth
MAXILLA:
Slope up & out
from the occlusal
plane
MANDIBLE:
Slope down & out
from the occlusal
plane
29. Lingual side of the distal end of the
lingual flange:
Guides the base of the tongue on top of
the lingual flange
Ensures the border seal at the back end
of mandibular denture
Base of tongue: emergency retentive
force
30. Most effective in retention when:
The denture bases are properly
extended to cover the maximum area
possible
The occlusal plane is at the correct level
The arch form of the teeth is in the
neutral zone
31. Resist dislodging forces to dentures with
an effective seal
Called Suction: resistance to removal
from the basal seat
No suction unless another force is
applied
Suction alone applied: serious damage
to the health of the soft tissues
32. Force exerted perpendicular to & away
from the basal seat of a properly
extended & fully seated denture
Pressure between the tissues & the
denture drops below the atmospheric
pressure: resists displacement
Retention area covered by the
denture
33. Most effective in retention when:
Denture has a perfect seal around its
entire border
Proper border molding with
physiological, selective pressure
techniques is carried out
34. Modest undercuts enhance retention:
resiliency of the mucosa & submucosa
Exaggerated bony undercuts:
compromise retention
Less severe ones: extremely helpful
Lateral tuberosities
Maxillary premolar areas
Distolingual areas
Lingual mandibular midbody areas
35. Undercuts necessitate adopting a
rotational path of insertion: resists vertical
displacement
Inferior to the retromolar pad: posterior
end placed first, from the superior &
posterior before rotating the anterior
segment down
36. Anterior alveolus: anterior part inserted
in a posterior & superior direction &
posterior border rotated over the
tuberosities
More important when other retentive
mechanisms are weak:
Loss of normal anatomical contours
Surgically created undercuts
37. Prominent alveolar ridges with parallel
buccal & lingual walls increase
the surface area maximize
interfacial & atmospheric forces
Limit the range of displacive force
directions
Flat ridges resist displacing forces
perpendicular to the basal seat, but
susceptible to movement parallel to it
38. Retentive force for the mandibular &
displacive for the maxillary- when the
person is upright
Weight of the prosthesis- gravitational
force insignificant
Heavy maxillary prosthesis unseat if the
other retentive forces – suboptimal
39. Increasing the weight of the mandibular
denture- beneficial when other retentive
factors are marginal
Xerostomia patients prefer heavier
maxillary prostheses
40. Commercially available
nontoxic, soluble material that is applied
to the tissue surface of the denture to
enhance retention, stability&
performance
Products which enhance the treatment
outcome
US: 33% of denture wearers use adhesive
products
Sale exceeded 200 million$ in 2001
41. Dentists should:
Educate all denture wearing patients
about the advantages, disadvantages&
uses of adhesives
Identify those patients for whom such a
product is advisable and/or necessary
for a satisfactory denture wearing
experience
42. STRICTLY INADVISABLE FORMS OF
ADHESIVES
Home reliner/repair kits
Paper/cloth pads
Self applied cushions
Thin wafers of water soluble material:
adherent to denture & basal tissue- don’t
flow
43. Possible sequelae:
Soft tissue damage
Alterations in occlusal relations & VD
Exacerbation alveolar bone destruction
44. Augment the already operating
retentive mechanisms
Enhance retention through optimizing
interfacial forces by:
1. Increasing the adhesive & cohesive
properties & viscosity of the interposed
medium
2. Eliminating the voids between the
denture base & its basal seat
45. Hydrated material formed by adhesives-
stick readily to the tissue surface & the
mucosal surface of the denture
More cohesive than saliva- resists
displacing pull
Increases viscosity of saliva
Hydrated material swells up in the
presence of saliva/water: obliterates
voids
46. Before early 1960’s: VEGETABLE GUMS
Karaya
Tragacanth
Xanthan
Acacia
Modest nonionic adhesion to denture &
mucosa
47. Drawbacks
Very little cohesive strength
Highly water soluble(particularly in hot):
washed out readily
Allergic reactions- Karaya & methyl
paraben(preservative)
Acetic acid odor
Short-lived & unsatisfactory adhesive
performance
48. Presently : SYNTHETIC MATERIALS
Mixtures of the salts of short acting
Carboxymethylcellulose (CMC)
long acting (polyvinyl methyl ether
maleate)
‘gantrez’ polymers
49. CMC hydrates & displays quick-onset
ionic adherence to both dentures&
mucous epithelium
Original fluid increases its viscosity &
CMC increases in volume- eliminates
voids between prosthesis & basal seat
Enhance the interfacial forces acting on
the denture
50. Polyvinylpyrrolidone (‘povidone’)
behaves like CMC
Gantrez salts: More protracted time
course than necessary for the onset of
hydration than CMC,
hydrate & increase adherence &
viscosity
51. Display molecular cross-linking more
pronounced & longer lived in Calcium-
Zinc gantrez than in Calcium- Sodium
gantrez
All polymers fully solubilised & washed
out by saliva : hastened by the presence
of hot liquid
52. OTHER COMPONENTS:
Petrolatum, Mineral oil, Polyethylene
oxide : bind the materials & make
placement easier
Silicone oxide, Calcium stearate:
powders to minimize clumping
Menthol, Peppermint oils: flavoring
Red dye: Coloring
Sodium borate, Methylparaben,
Polyparaben: Preservatives
53. No reports of tissue reactions excepting
uncommon allergic reactons to karaya/
methyl paraben
Earlier formulations had benzene-
carcinogen
Lessened inflammation of the underlying
tissues if dental hygiene is maintained
54. Incisal bite force in well fitting dentures
over well- keratinized ridges with
favorable anatomical features
Can be improved for well fitting dentures
over inferior basal tissues
55. Frequency of dislodgement - chewing
Increased confidence & security in
chewing- but no improvement in
chewing performance
Improvement in chewing efficiency
during adjustment to new dentures
56. OBJECTIONS:
Grainy/ gritty texture of the powder
Taste or sensation of semidissolved
adhesive material that escapes from the
posterior & other peripheries
Difficulties in removing adhesives from
the oral tissues & denture
The cost of the material
57. Well made complete dentures do not
satisfy a patient’s perceived retention &
stability expectations
Candidates for implant supported
prosthesis , precluded by health,
financial or other restraints
58. Salivary dysfunction
Xerostomia- medications, irradiation,
systemic disease, disease of salivary
glands
Need to be educated- deliberately
moisten the adhesive bearing denture
59. Neurological disorders
CVA- oral cavity insensitive to tactile
stimulation/ paralysis of oral musculature
Help to accommodate to new dentures
Dentures fabricated before stroke
61. Resective surgical/ traumatic
modifications of the oral cavity
Oral neoplasia
Loss of integrity of intraoral structures
Even in the presence of surgically
created rotational undercuts
62. Poorly fitting or improperly fabricated
prosthesis
Hypersensitivity to any of the
components
63. Major information source to the patient-
dentist
Effects of powder formulations do not last
long compared to cream formulations
Initial ‘hold’ is better for them compared to
creams
Easier to clean out
The least amount of the material that is
effective should be used:
0.5-1g/denture unit
64. POWDERS:
Clean prosthesis moistened- thin even
coat of adhesive sprayed onto the tissue
surface of the denture
Excess is shaken off & it is firmly seated
Sprayed denture slightly moistened with
water before insertion- inadequate
salivation
65. CREAMS
2 approaches
1. Placement of thin beads of adhesive in
the depth of the dried denture in the
incisor & molar regions
Anteroposterior bead in the midpalate-
maxillary
66. 2. Small spots of cream placed at 5mm
intervals throughout the fitting surface of
the dried denture- even distribution
Denture then seated & inserted firmly
Requires moistening before placement in
cases of xerostomia
67.
68. Daily removal of the adhesive- soaking
prosthesis in water / soaking solution
overnight
If not possible, running hot water over
the tissue surface & scrubbing with a
suitable hard bristle brush
69. Adhesive adherent to alveolar ridges &
palate – rinsing with warm/ hot water-
firmly wiping the area with
gauze/washcloth saturated with hot
water
Discomfort will not be resolved by
placing a ‘cushioning layer’ of adhesive
under the denture
70. Professional management required:
Pain /soreness
Gradual increase in the quantity of
adhesive required
Patients recalled annually for mucosal
evaluation& prosthesis assessment
71. Frequently regarded as unesthetic,
impedes dentist’s ability to appraise the
health of oral tissues & the true
adaptation
Use of denture adhesive & residual ridge
resorption- believed to be correlated:
no scientific basis
Reduce the amount of lateral
movements that denture undergoes
while in contact with basal tissues
72. Patient may ignore the need for
professional help when dentures actually
become ill fitting
Integral part of a professional service &
their adjunctive benefits must be
recognised
73. Irrespective of the underlying reasons for
the patient’s dissatisfaction with the
prosthesis, dentist must realize that a
patient’s judgement of the treatment
outcome is what defines prosthodontic
success
Though complete denture retention is a
complex phenomenon, it is every patient’s
invariable need that the prosthesis stays firm
& stable during function & hence every
possible attempt should be made by the
dentist to achieve it
74. Prosthodontic Treatment for Edentulous
Patients- Zarb & Bolender,Twelfth edition
Essentials of CompleteDenture
Prosthodontics- Sheldon Winkler,Second
edition
Textbook of Prosthodontics- Deepak
Nallaswamy
Complete Denture Prosthodontics- John
Joy Manappallil