overdenture

1. IMPLANT SUPPORTED
OVERDENTURE
Presented by :- Dr. Anuja Gunjal
19/01/18
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2. Content
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 Introduction
 Advantages Of Implant Supported Prostheses
 Implant Overdenture Advantages Versus Fixed Prosthesis
 Disadvantages Of Overdenture
 Classification Of Prosthesis Movement

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 Overdenture Attachment
 Overdenture Treatment Options
 Step-By-Step Restorative Procedure
 Discussion
 Summary
 References

4. Introduction
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According to GPT 9:-
 overdenture o΄var-dĕn΄chur n: any removable dental prosthesis that covers
and rests on one or more remaining natural teeth, the roots of natural teeth,
and/or dental implants; a dental prosthesis that covers and is partially
supported by natural teeth, natural tooth roots, and/or dental implants;

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 The consequences of total tooth loss includes bone resorption, changes in
orofacial morphology, and psychological effects.
 Treatment with conventional complete denture is successful when residual
alveolar ridges are favorable.
 But, such treatment will not be successful when,
1. Residual alveolar ridges are resorbed
2. Movement of denture leads to discomfort, pain, poor function
3. The patients have poor neuromuscular control

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 These difficulties can be overcome by the use of osseointegrated implants
to support, retain and stabilize dentures.
 The placement of implants enhances the support, retention, and stability of
an overdenture.

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Prosthetic Options In Implant
Dentistry

8. ADVANTAGES OF IMPLANT SUPPORTED
PROSTHESES8
 Prevents anterior bone loss
 Improved aesthetics
 Improved stability (reduces or
eliminates prosthesis movement)
 Improved occlusion (reproducible
centric relation occlusion)
 Decrease in soft tissue abrasions
 Improved chewing efficiency and
 Increased occlusal efficiency
 Improved prosthesis retention
 Improved prosthesis support
 Improved speech
 Reduced prosthesis size (reduces
flanges)
 Improved maxillofacial prostheses

9. IMPLANT OVERDENTURE ADVANTAGES
VERSUS FIXED PROSTHESIS
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 Fewer implants (RP-5)
 Less bone grafting required before
treatment
 Less specific implant placement
 Soft tissue drape replaced by acrylic
 Improved peri-implant probing
(follow-up)
 Hygiene
 Reduced stress
 Nocturnal parafunction (remove
prosthesis at night)
 Lower cost and laboratory cost (RP-
5)
 Less bone grafting (RP-5)
 Easy repair
 Laboratory cost decrease (RP-5)
 Transitional device is less
demanding than a fixed restoration

10. DISADVANTAGES OF MANDIBULAR
OVERDENTURE10
 Psychological (need for non-removable teeth)
 Greater abutment crown height space required
 More long-term maintenance required
 Attachments (change)
 Relines (RP-5)
 New prosthesis every 7 years
 Continued posterior bone loss
 Food impaction

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12. Classification Of Prosthesis Movement
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 PM 0 : No movement of prosthesis, requires implant support similar to fixed
prosthesis
 PM 2: Prosthesis with hinge motion
 PM 3: Prosthesis with hinge and apical motion
 PM 4: Allows movement in four directions
 PM 6: All ranges of prosthesis movement

13. Overdenture Attachment
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 An overdenture attachment permits movement during function and removal
from the mouth.
 The attachment should offer the possibility of controlling the degree of
retention.
 A loose attachment used at initial delivery ensures prosthesis movement and
decreases screw loosening during the first few months.
 A gradual increase in retentive capability may be achieved later by replacing
the component within the encapsulator by a more retentive one.

14. O-Ring or Ball Attachments
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 O-rings are doughnut-shaped, synthetic polymer gaskets that possess
the ability to bend with resistance and then return to their approximate
original shape .
 In part, this feature results from a three-dimensional network of flexible
elastomeric chains.

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 The O-ring originally was made of natural rubber. The latex was heat treated
with sulfur (vulcanization) to improve its properties.
 The resultant polymer, known as polyisoprene.
 The advantages of O-rings are ease in changing the attachment, the wide
range of movement, low cost, different degrees of retention, and possible
elimination of the time and cost of a superstructure for the prosthesis

16. O-Ring Versus Prosthesis Movement
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 An O-ring is compressed radially between two mating surfaces consisting of
a post and a metal encapsulator into which the O-ring is installed
 In situations that require few or no moving parts or movement, the O-ring is
classified as static (e.g., gasket or washer).
 In situations involving reciprocation, rotation, or oscillating motion relative to
the O-ring, it is classified as dynamic.

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 O-rings may allow motion in six different directions.
 However, if a superstructure connects the implants, the range of motion
decreases

18. Metal Encapsulator
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 A metal or plastic encapsulator
permits the easy replacement of the
O-ring after wearing or damage.
 This eliminates the need for
chairside cold curing of a new
attachment in place.

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 Virtually every O-ring encapsulator has an undercut region that houses the
O-ring, called the internal cavity.
 The overall size of the encapsulator is larger than the O-ring and should be
placed on the O-ring post during fabrication of the prosthesis to ensure
adequate room is present for the volume of the restoration

20. O-Ring Post
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 The O-ring post usually is made of machined titanium alloy when used as an
independent attachment or a delrim post that is waxed and cast in precious
metal along with the connecting superstructure bar joining root forms. The
post has a head, neck, and body.
 The head is wider than the neck and the O-ring is compressed over the head
during insertion.
 Under the head the post has an undercut region called the neck or groove,
which the ring engages after it stretches over the head

21. O-Ring Size
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 O-rings and posts may come in a variety of diameters depending on the
space available within the volume of the prosthesis.
 Typically three sizes of O-rings are used in implant prostheses.
 The internal diameter (hole diameter) of the O-ring must be smaller than the
post neck and fit snugly in the groove diameter.
 The O-ring inside diameter will be stretched to 1% to 2% (not to exceed 5%)
when in place against the post neck .

22. O- Ring Hardness
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 O-ring hardness is measured with a durometer , which measures surface
resistance to the penetration of an indentation point.
 The resultant numerical rating of hardness ranges from 0 to 100 in a Shore A
Scale.
 The softest O-rings are usually 30 to 40, and the hardest are 80 to 90.
 Color is not indicative of hardness. In fact, most O-rings are black.
 Sometimes, however, for production coding or cosmetic reasons,
nonstandard colors are desired

23. O-Ring Material
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 The U.S. Food and Drug Administration has issued guidelines for O-rings
used in medicine.
 The elastomeric materials meeting these requirements include (1) silicone,
(2) nitrile, (3) fluorocarbon, and (4) ethylene-propylene.
 The materials are available from a variety of industrial manufacturers.

24. Hader Bar and Clip
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 Helmut Hader developed the Hader bar and rider system in the 1960s.
 Its present form has been used for almost 30 years. English, Donnel, and
Staubli modified the system in 1992 to form the Hader EDS system.
 The EDS bar system is only 3 mm high, whereas the original was 8.3 mm in
height.
 Three different retention strengths and a 20-degree clip rotation, which
greatly improves the flexibility of the system for a range of patient needs or
desires.

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 The standard or EDS Hader bar has a round superior aspect and an apron
toward the tissue below.
 The apron acts as a stiffener to improve the strength of the bar and limit its
flexibility.
 The length of the apron or stiffener is related to the amount of clearance
between the bar and gingiva.

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 The total height of the Hader bar and clip assembly may be as low as 4 mm,
rather than the 5 to 7 mm required for an O-ring system .
 Therefore a lesser moment of force is placed on the bar during rotation, and
less clearance is required under the denture base.

27. Overdenture Treatment Options
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29. OVERDENTURE OPTIONS 1
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30. Patient selection criteria – OD 1
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 Opposing a maxillary full denture
 Anatomical conditions are good to excellent (division A or B anterior and
posterior bone.
 Posterior ridge form is an inverted U shape.
 Patient’s needs and desires are minimal, primarily related to lack of
prosthesis retention.
 Edentulous ridge, not square with a tapered dentate arch form
 Cost is the primary factor.
 Additional implants will be inserted within 3 years.

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 The ultimate goal in the treatment plan is to convert OD-1 patients to a RP-4
or fixed prosthesis with more implant support and stability before the loss of
the posterior bone in the mandible occurs behind the foraminae.
 As soon as the patient can afford two more implants, the implants should be
placed in the A and E position, and all four ABDE implants should be
connected with a bar that may be cantilevered to the posterior and help
reduce the posterior bone loss.

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 If an additional implant may be inserted (after the initial two), it may be
positioned in the C position, or if bone height and width distal to one mental
foramen are adequate, the additional implant may be positioned in one of
the first molar regions.
 With implants in the A, B, C, D, E position or A, B, D, E, and molar position,
the connected implants and cantilevered bar will result in a RP-4 or fixed
restoration and will help maintain posterior bone.
 The bar may be cantilevered to provide posterior support because of the
greatly improved anteroposterior distance (A-P spread) between splinted

37. OVERDENTURE OPTION 2
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38. Patient selection criteria – OD 1
 Opposing arch is a maxillary denture.
 Anatomical conditions are good to excellent (division A or B bone in anterior
and posterior regions).
 Posterior ridge forms an inverted U shape.
 Patient’s need and desires are minimal, primarily related to lack of retention.
 Patient can afford new prosthesis and connecting bar.
 Additional implants will not be inserted for more than 3 years.
 Low patient force factors (e.g., parafunction)
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44. Disadvantages of A and E Splinted Implants
(First Premolar to First Premolar)44
 Implants joined with straight bar are lingual to ridge.
• Difficulty with speech
• Anterior tipping of overdenture
• Five times greater bar flexure than B and D positions
 Implants are joined with anterior curved bar.
• Greater bar flexibility (nine times the B and D positions)
• Increased screw loosening
• Increased moment forces on anterior aspect of prosthesis

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• Attachment of curved bar may prevent prosthesis movement
• Bite force is higher than for B and D positions.
• Greater lateral load from prosthesis to implants than B and D positions

46. Disadvantages of OD2
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 not indicated in C-h or D bone and are not indicated when opposing anterior
or posterior natural teeth.
 The increase in crown height and the poorer posterior ridge form or the
increase in bite forces and rigid opposing arch place additional stresses on
the implant system and increase complications.
 Tissue hyperplasia under the bar, more difficult hygiene under the bar
(compared with option 1), and a more expensive initial treatment option
compared with option 1 (because a bar and retentive elements are
included).

47. OVERDENTURE OPTION 3
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48. Advantages
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 6 times less bar flexure compared with
A and E positions
 Less screw loosening
 Less metal flexure
 Three implant abutments
 Less stress to each implant compared
with A and E implants
 Greater surface area
 More implants
 Greater anteroposterior distance
 One-half moment force compared with A
and E implants
 Less prosthesis movement
 One implant failure still provides
adequate abutment support

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 The OD-3 treatment option is usually the first option presented to a patient
with minimal complaints who is concerned primarily with retention and
anterior stability of the IOD when cost is a moderate factor.
 The posterior ridge form should be evaluated because it determines the
posterior lingual flange extension of the denture, which limits lateral
movement of the restoration in this treatment option.

54. OVERDENTURE OPTION 4
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55. Patient selection criteria OD-4
 Moderate to severe problems with traditional dentures
 Needs or desires are demanding
 Need to decrease bulk of prosthesis
 Inability to wear traditional prostheses
 Desire to abate posterior bone loss
 Unfavourable anatomy for complete dentures
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56.  Problems with function and stability
 Posterior sore spots
 Opposing natural teeth
 C–h bone volume
 Unfavourable force factors (parafunction, age, size six, crown height space
>15 mm)
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59. OVERDENTURE OPTION 5
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60. Patient selection criteria : OD-5
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 Moderate to severe problems with
traditional dentures
 Needs or desires are demanding
 Need to decrease bulk of prosthesis
 Inability to wear traditional prostheses
 Desire to abate posterior bone loss
 Unfavourable anatomy for complete
dentures
 Problems with function and stability
 Posterior sore spots
 Moderate to poor posterior anatomy
 Lack of retention and stability
 Soft tissue abrasion
 Speech difficulties
 More demanding patient type

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62. STEP BY STEP PROCEDURE
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69. DISCUSSION
 Treatment option OD-1 - one-legged chair. A one-legged chair can support
your weight but provides very little stability.
 OD-2 or OD-3 - two-legged chair. The prosthesis provides some vertical
support but can still rock back and forth and provides limited stability in the
posterior regions.
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70.  Option OD-4 with four implants is compared to a three-legged chair. This
system provides improved support and has improved stability.
 A four-legged chair provides the greatest support and stability and is similar
to OD-5, which is maximum for prosthesis support and stability because it is
a RP-4 design.
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71. REVIEW OF LITERATURE
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72. A Functional Impression Technique For
An Implant-supported Overdenture: A
Clinical Report
Uludağ B1, Sahin V. A functional impression technique for an implant-
supported overdenture: a clinical report. J Oral Implantol.
2006;32(1):41-3.
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 A 50-year-old woman - poor retention of her mandibular complete denture
 initial clinical examination - the lack of retention of the mandibular denture
due to the resorption of the alveolar ridges
 a treatment plan - placement of 2 implants in the interforaminal region to
provide retention for the mandibular denture.

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75. Summary
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 A functional impression procedure is described to fabricate an implant-
supported mandibular overdenture.
 Two stage impression technique records the alveolar mucosa in a functional
state and the implant components accurately.

76. Complications Associated With The
Ball, Bar And Locator Attachments
For Implant- Supported
Overdentures
Cakarer S, Can T, Yaltirik M, Keskin C. Complications associated with the ball, bar and
Locator attachments for implant-supported overdentures. Med Oral Patol Oral Cir
Bucal. 2011 1;16(7):e953-9.
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 The purpose - to evaluate the complications associated with the different
attachments used in implant-supported overdentures, including prosthetic
problems and implant failures.
 A comparison of ball, bar and Locator attachments, in completely edentulous
patients with two, three or four implants, was conducted.
 A total of 36 edentulous patients (20 female, 16 male)
 The patients were treated with 95 implants
 The mean follow-up time was 41.17 months.

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 Prosthetic complications including, fractured overdentures, replacements of
O-ring attachment and retention clips, implant failures, hygiene problems,
mucosal enlargements, attachment fractures, retention loss and
dislodgement of the attachments were recorded and evaluated.
 The recall visits at 3, 6, 12 months and, annually thereafter.

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 14 complications - ball attachment group
 7 complications - bar group
 No complications were observed in the locator group.
 Conclusion:- locator system showed superior clinical results than the ball
and the bar attachments, with regard to the rate of prosthodontic
complications and the maintenance of the oral function.

80. Circumferential Bone Loss Around Splinted And
Non-splinted Immediately Loaded Implants
Retaining Mandibular Overdentures: A
Randomized Controlled Clinical Trial Using Cone
Beam Computed Tomography
Elsyad MA, Khirallah AS. Circumferential bone loss around splinted and nonsplinted
immediately loaded implants retaining mandibular overdentures: A randomized
controlled clinical trial using cone beam computed tomography. J Prosthet Dent
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 The purpose - to assess circumferential bone loss around splinted and non-
splinted immediately loaded implants retaining mandibular overdentures,
using cone beam computed tomography (CBCT).
 30 completely edentulous participants were allocated to 2 groups and
received 2 implants in the canine region of the mandible.
 Implants were either left nonsplinted (with ball attachment [BA]) or splinted
(with bar attachment [RA]). Mandibular overdentures were connected to the
implants 1 week later.

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 CBCT was used to evaluate vertical bone loss (VBL) and horizontal bone
loss (HBLo) bone loss at the distal (D), buccal (B), mesial (M), and lingual
(L) sites of each implant upon overdenture insertion (baseline, T0), 1 year
(T1) and 3 years (T3) after insertion.
 Repeated measures ANOVA was used for statistical analysis (a=.05).

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 No significant difference in the survival rate
 VBL and HBLo increased significantly at T3 compared with T1 for both
groups (P<.005).
 At T1 and T3, BA had more significant VBL than RA (P<.001), while HBLo did
not differ significantly between groups.
 For both groups, a significant difference was found in VBL and HBLo
between implant sites (P<.001).
 The B site recorded the highest VBL, and the L site recorded the lowest VBL.
 The M and D sites recorded the highest HBLo, and the B and L sites
recorded the lowest HBLo.

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 Conclusion :- Two nonsplinted immediately loaded implants retaining
mandibular overdentures were associated with significantly higher vertical
and horizontal circumferential bone loss than those associated with splinted
implants after a follow-up of 3 years

86. BITING FORCE AND MUSCLE ACTIVITY IN
IMPLANT-SUPPORTED SINGLE
MANDIBULAR OVERDENTURES OPPOSING
FIXED MAXILLARY DENTITION.
Wafa'a R, Abbas NA, Amer AA, Abdelkader AA, Bahgat B. Biting force and muscle activity in
implant-supported single mandibular overdentures opposing fixed maxillary dentition. Implant
dentistry. 2016;25(2):199-203.
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 Aim :- to investigate the relation between biting force and
masticatory muscle activity in patients treated by 3 modalities
of single mandibular dentures.
 Forty implants were placed in 10 patients with completely edentulous
mandibles.
 The study was divided into 3 treatment stages. Initially, each patient received
a conventional mandibular complete denture.
 At the second stage, 4 mandibular implants were placed and the denture
was refitted to their abutments.

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 Third stage comprised connecting the denture to the implants through ball
attachments.
 During each treatment stage, maximum biting force and muscle activity were
measured during maximum clenching and chewing of soft and hard food.
 Biting force demonstrated a statistically significant increase by time for the 3
treatment stages.

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 The highest muscle activity was recorded for the conventional denture
followed by the implant-supported overdenture without attachment, whereas
the lowest values were recorded for the implant-supported overdenture with
attachment.
 Conclusion :- Biting force was related mainly to the quality of denture
support. Muscle activity was higher in patients with conventional denture
than with implant-supported prostheses (with or without attachments).

90. Summary
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 Implant overdentures borrow several principles from tooth supported
overdentures.
 The advantages of implant overdentures relate to the ability to place rigid,
healthy abutments in the anterior positions of choice.
 The number, location, superstructure design, and prosthetic range of motion
can be predetermined to base these factors on a patient's expressed needs
and desires.

91. REFERENCE
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 Misch CE: Dental Implant prosthetics, 2005, Mosby, Inc. Page no : 206-251
 Misch CE: Dental Implant prosthetics, 2005, Mosby, Inc. Page no : 573-599,
753-828
 Uludağ B1, Sahin V. A functional impression technique for an implant-
supported overdenture: a clinical report. J Oral Implantol. 2006;32(1):41-3.
 Cakarer S, Can T, Yaltirik M, Keskin C. Complications associated with the
ball, bar and Locator attachments for implant-supported overdentures. Med
Oral Patol Oral Cir Bucal. 2011 1;16(7):e953-9.

92. 116
 Elsyad MA, Khirallah AS. Circumferential bone loss around splinted and nonsplinted
immediately loaded implants retaining mandibular overdentures: A randomized
controlled clinical trial using cone beam computed tomography. J Prosthet Dent
2016;116(5):741-8.
 Wafa'a R, Abbas NA, Amer AA, Abdelkader AA, Bahgat B. Biting force and muscle
activity in implant-supported single mandibular overdentures opposing fixed
maxillary dentition. Implant dentistry. 2016 Apr 1;25(2):199-203.

93. THANK YOU.
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