The document discusses tooth-supported overdentures, emphasizing their role in preventive prosthodontics and addressing issues of occlusal stability and esthetics in patients with compromised dental arches. It outlines the advantages and disadvantages of overdentures, selection of abutment teeth, preparation and impression techniques, and attachment systems, highlighting both the technical challenges and long-term benefits of this therapy. The use of overdentures can lead to favorable outcomes, especially with advancements like osseointegration for better stability.

1. TOOTHSUPPORTED
OVERDENTURES
Presented by:-
DR. SNEHA.

2. INTRODUCTION
 In the past the extraction of entire dentitions with
complete denture replacements used to be promoted as
an inexpensive and permanent solution for oral health
care.
 Preventive prosthodontics emphasizes the importance of
any procedure that can delay or eliminate future
prosthodontic problems.The overdenture is a logical
method for the dentist to use preventive prosthodontics.

3. SEQUALAE
OFACD
PATIENT
LOSS OF OCCLUSAL
STABILITY
RESIDUAL RIDGE
RESORPTION
UNDERMINED ESTHETICS
IMPAIRED
MASTICATION

4. NEED FOR
OVERDENTURE ????
Reconcile a need for
maximum support in
morphologically
compromised dental
arches
Equally compromised
esthetic
appearance resulting from
undersupported circumoral
tissues

5. DEFINITION
 An overdenture is defined as a removable
prosthesis that covers the entire occlusal
surface of root or implant (preiskel 1 edition)

6. MORE RESIDUAL RIDGE
INTEGRITY
MORE DENTURE
STABILITYAND
RETENTION
RETAINED “NATURAL
FEELING”
SIMPLEALTERNATIVE
ADVANTAGES

7. Disadvantages
Depends on patients oral hygiene
comittments.
Extensive abutment design modifications
required in inadequate interarch space.
Increases cost in the patients with
compromised periodontal heath of the
abutments.
It is considered as a time dependent
transition to complete denture therapy.

8. INDICATIONS
GROUP 1 GROUP 2
• Few remaining
teeth that may be
healthy or
reversible
periodontal
diseases.
• Minimal
prosthodontic
intervention is
required.
• Mutilated or
severly
compromised
dentitions.
• Heading in
edentulous
direction.
• Selective
extraction
required.

9. SELECTION OF
ABUTMENTTEETH
PERIODONTAL
STATUS
MOBILITY
LOCATION COST
ENDO AND
PROSTHODONTIC
CONSIDERATION

10. PERIODONTAL
STATUS
 Should have healthy periodontal tissues, if not rendered by appropriate
PDL therapy.
 Slight tooth mobility is not a contraindication.
 A circumferential band of attached gingiva, albeit a narrow one is
regarded as a mandatory requirement for abutment selection.

11. ABUTMENTSELECTION
IN mandible canines and premolars
are best overdenture abutments
In maxilla incisors are
frequently used.

12. Maxillary teeth advantages Disadvantages
• CENTRAL INCISORS
• LATERAL INCISORS
 Ideal location, provide protection
to premaxilla.
 Widely separated, facilitating
Diminished root surface area
plaque control.
 Tissue undercuts do not pose a
problem.
 Path of placement/removal is not
compromised.
 Ability to create a flange/
peripheral seal.
× Proximity and alveolar
prominence may complicate
utilization.
× Diminished root surface area.

13. • CANINES  Longest root of the
anterior teeth.
× Diverging facial
tissue undercuts
× Overcontoured
flanges
× Excessive lip
support
× Potentially
uncomfortable
placement/removal
of prosthesis
× Complicates
placement of
prosthetic teeth
× compromise the
peripheral seal
From Nelson DR, von Gonten AS: Biomechanical and esthetic considerations for maxillary anterior
overdenture abutment selection, J Prosthet Dent 72:133-136, 1994.

14. One tooth per quadrant is
recommended.
If recommendations is exceeded,
retained teeth should be preferably not
the adjacent ones. or there should be
several millimeters of space between the
reduced tooth forms.
Hammer and anvil concept should be
kept in mind.

15. ENDODONTIC
AND
PROSTHODONTIC
STATUS
Anterior single rooted teeth are easier
and less expensive to manage .
Recent year cast copings are eclipsed by
composite and alloy restorations.
The clinical crowns can be modified for
technical convenience and treated with
sealant restorations or fluoride
applications.

16. METHODOFABUTMENT PREPARATION
It is our impression that the essential
feature in this technique is not the type of
attachment used per se but the following
basic principles:
1. “Bare tooth”:-Maximum reduction of
the coronal portion of the tooth
should be accomplished.
 Patients with advanced pulpal
recession can undergo coronal
reduction without the need for
endodontic treatment.

17.  This preparation is made when time is
needed to evaluate the status of
selected abutment teeth and when a
patient’s (usually an elderly one’s)
general health precludes several dental
appointments.
 COST effective.
2. “GOLD COPING”:- a gold coping is
necessary and can be prepared with or
without a post or retentive pins,
depending on the amount of tooth
structure remaining above the gingival
attachment.

18.  The gold coping does involve an
additional expense, but some patients
are uncomfortable with the sight of
discolored and “unprotected” roots in
their mouth.
 The patient’s susceptibility to caries
must also be considered .
 Tooth preparation is similar to that for a
complete gold crown,with or without
additional pin retention, and it includes
a combination of shoulder and
chamfered gingival margins as dictated
by the amount of residual tooth
structure.

19. 3. “Precision-retained abutment concept” :-
 It is used in RPDs and modified for use with overdenture abutments.
 It is a technically ingenious idea and offers a diversity of techniques.
The Dalbo Rotex chairside attachment system: male portion cemented in the abutment
teeth and female housing embedded in the acrylic of the overdenture

20. Ceka-Revax attachment system: the male stud-type attachment is soldered to a coping.
Fixation is achieved by the female housing embedded in the (maxillary) overdenture.

21. SUPPORT FOR
OVERDENTURES
 It is important to realize that the causes of failure
inherent in the complete denture prosthesis are not
overcome by using attachment fixation.
 Failures of the hybrid prosthesis occur not because of
the attachments hut because of improper attachment
selection and failure of the dentist to develop
maximum denture base extension, atmospheric seal,
and, for mandibular bases, coverage of the retromolar
pad.
 Use of the attachment introduces another factor in
basic prosthetic design, that is, the demand for an
exact attachment-prosthesis relationship.

22. TOOTH
PREPARATION
A B C D E
Design of overdenture support preparations.
A. Maximum reduction without endodontics, rounded and polished,
vertical support only.
B.Three to eight millimeters of overdenture is "telescope," vertical and
lateral support.
C. Double casting "telescope," retention,vertical, and lateral support.
D. Residual root with or without endodontics.
E. Implant.

23. Design of overdenture support preparations.
A. Maximum reduction, endodontically treated, cemented cast
coping retained by pins.
B. cemented cast coping.
C. Dowel coping with attachment.
D. Composite or alloy restored with orientation seat for
overdenture.
E. Minimal preparation, endodontically treated, rounded, restored
with composite or alloy.
A
B C D E

24. IMPRESSION
TECHNIQUES
 The impression technique and materials vary with
personal preference. Elastomeric materials as well as
individual compound impressions allow the dentist to
choose silverplated or stone dies.
 hydrocolloid impressions permit to use only stone dies.
 Incorporations of a dowel in an impression can
complicate otherwise routine impression procedures .
 An alternative method is to make an individual or full
impression of preparations, join the dowels to the
copings with resin, transfer them,solder the dowels to
the copings, and prepare the casts and dowel copings
for subsequent attachment positioning and
overdenture fabrication .

25. LABORATORY
PROCEDURES
One cause of failure of post coping preparations that carry attachments
is the lack of hulk at the attachment-post-coping interphase (right).This
causes fracture or opening of the coping. Left drawing illustrates a
proper inlay seat that positions coping, prevents rotation, and provides
necessary bulk.

26. Dowelcopingshould
provideagradualgingival
bulgetoprotectmarginal
gingiva.
joint.
• The occlusal surface of the coping is modified
to accept the type of attachment used.
• The attachments are soldered to the coping
after it has been cast and rough finished.
• The orientation of most stud and bar
attachments is established with a
parallelometer.
• Generally attachment · orientation in relation
to the coping is dictated by the resin tooth
position and the buccolingual and
occlusogingival space available.

27. DOWEL
DESIGNS
 CUSTOMIZED CAST DOWELS
Waxed dowels require bulk for adaptation of the wax
pattern and usually are not long enough to provide
resistance against dislodgment.
 PRE FABRICATED RESIN PATTERNS
The prefabricated dowel patterns are provided with a
matched set of burs for preparing the dowel space.The
cross-sectional strength of a pattern dowel is
considerably less than that of a prefabricated metal
dowel of the same size,for the metal dowels are drawn
from a high-fusing alloy, different than that used for the
copings, and do not have the potential porosity and
fracture of a cast dowel.

28. PRE FABRICATED METAL DOWELS
• The cross-sectional strength of a pattern dowel is considerably less than that of a prefabricated metal dowel of the
same size,for the metal dowels are drawn from a h igh-fusingalloy, different than that used for the copings, and
do not have the potential porosity and fracture of a cast dowel.
THREADED DOWELS
• Threaded dowels provide mechanical fixation inaddition to cementation .TheVK and Kurer systems offer excellent
retention with the threading.
• A disadvantage with this type of dowel is that the tooth can be fractured during final cementation by using too
large a screw for the cross section of the tooth.
DOWEL SYSTEMS
• MOOSER SYSTEMS
• SCHENKER STEP PIVOT
• VK SCREW
• KURERSCREW
• WHALEDENT PARAPOST
• PARAKELCI KIT

29. ATTACHMENTS
Coronal
1. Intracoronal attachments
2. Extracoronal attachments
Raclicular
3.Telescope stud attachments
4. Bar attachments
 Joints
 Units
5. Auxiliary attachments
• Screw units
• Pawl ,Connectors
• Bolts
• Stabilizers/balancers
• Interlocks
• Pins/screws
• Rests
.
• Groups 3 through 5 are primarily related to the
overdenture service

31. TYPES
 RESILIENT STUDS
 act as a safety valve for any overload situation.
 No two resilient attachment systems should oppose
each other
 No attempt should be made at equilibrating or
establishing permanent records or relining procedures
without locking the resilient attachments.
 NON RESEILIENT STUDS
 The nonresilient stud attachments are used when
Interocclusal SPACE IS limited.They should be used
when the teeth are stable or when the dentist does not
desire movement or potential movement of the
overdenture

32. TYPESOFSTUD
ATTACHMENTS
 ANCHROFIX
 Resilient pressure
button
 Line drawing of
Ancrofix shows
threaded stud section
and housing with four
lamellae surrounded by
Teflon ring. Height of
this attachment is 3.2
mm.

33. Baer F. G. (European).
• it is a small stud attachment (2.2mm high), has an integral post and
solder base. The housing has two horizontally opposing lamellae with a
PVC (polyvinyl chloride) ring to assure operation; the lamellae provide
adjustable friction grip retention.
Biaggi (European).
The Biaggi attachment is similar to the Baer series. The male component
consists of a solder base with an adjustable split ball.There is a spacing
ring for tissue resiliency. The female housing has two adjustable
horizontal lamellae (split ring) that thread into the female housing. The
movement is vertical, and rotational movement is available. The overall
height of the attachment is 3.4 mm.

34. BONA BALL ANCHOR
• IT consists of a solder base with a sphere, a spacing ring for mounting, and an
adjustable housing with four asymmetrical spring lamellae that provide the retention.
The lamellae are surrounded by a PVC ring to assure their action.The overall height of
the attachment is 4 mm.
Bona-Ball anchor is an example of a
tissue resilient rotational stud
attachment
The eight asymmetric lamellae provide a softer and more
precise retention than earlier model.
Overall height is 3.3 mm.

35. DALBO STUD ATTACHMENT
Rigid unit
Ball and socket unit
(Vertical and
rotational movement)
Nylon ring – protects the lamella
  Retention – altering the positions
of free ends of the lamella

36. ROTHERMAN ECCENTRICATTACHMENT
Button shaped attachment
Patrix – eccentric cylinder
with undercut or groove
Matrix – Clip or clasp arm
Activation : Bending the
clasp arm towards center
Resilient unit
Rigid units

37. GERBERATTACHMENT
Resilient gerber Rigid gerber
 Largest of the stud unit
 Resilient – spring
controlled vertical plane
 Patrix – threaded post
 Matrix – retention spring and
ring
Disadvantages :
Complex attachment system
Requires more space
Permits little rotation

39. BAR ATTACHMENTS
Bar can be attached to:-
• Coping or crowns over the vital teeth
• Post coping on endodontically treated teeth
• Screwed down into the coping (implant system)
Types of bar attachments :
Customised bar
Dolder bar
Ackermann’s bar
CM rider bar
Hader bar
Andrews bar

40. Two groups of bar attachments :
1) Bar units - rigid
2) Bar joints – permits rotation
Round / circular Oval / egg shaped „U‟shaped /
parallel sided bars
Multiple sleeve bar jointsSingle sleeve bar joints
Depending on cross section
BAR JOINTS

41. DOLDER BAR
Egg shaped bar in cross section
Open sided sleeve
Two sizes 3.5mm x 1.6mm,
3.0mm x 2.2mm
Spacer – degree of movement

42. ACKERMANN BAR
Available in different cross
section
Circular cross section – can
be bent in all planes

43. CM BAR
 Made up of precious /
semiprecious alloy
 Retention tags in long axis
of the bar
The C. M . bar is a prefabricated
bar 100 mm by 10 mm by 1 . 8 mm, which
is provided with a copper template for the
milling technique

44. Advantages of bar attachments :
Rigidly splint the teeth
Provides good retention, stability and support
Provides cross arch stabilization
Positioned close to the alveolar bone (exhibit less leverage)
Disadvantages :
Bulk of bar
Plaque accumulation
Wearing
Soldering procedure
Manual dexterity

45. DISADVANTAGES
Apart from the increased expense,
the risks are increased technical
demands and difficulties,
particularly when repairs are
required, oral hygiene maintenance
requirements may be more
demanding, and esthetic plus
interarch space concerns are usually
more severe.

46. LOSSOF
ABUTMENT
TEETH
 SEVERAL STUDIES have shown that After 5 to 6 years,
about 10% of abutment teeth supporting overdentures
were lost.The most frequent causes were periodontal
disease (about70%), caries (about 25%), and
endodontic complications(about 5%).
 Ideally the patient must be well motivated to maintain
the hygienic phase of periodontal care.
 Unfortunately actual “loss of dentures” was more a
problem then loss of abutments.
 Flouride applications are recommended to prevent
caries.

47. CLINICAL
PROCEDURES
TOOTH SUPPORTED COMPLETE
DENTURE
The important principles of complete
denture construction must be respected
and when required,matched to the
technical and laboratory dictates of
selected attachment type.
One frequently encountered problem of
tooth-supported complete denture
service is the tendency for an unfavorable
gingival response around the abutment
teeth.

48. 1) movement
of the denture base
2) poor oral hygiene with
failure to remove plaque
3)excess space in the prosthesis
around the gingival margins of the
abutment teeth
GINGIVAL INFLAMMATION

49. TOOTH
SUPPORTED
IMMEDIATE
DENTURE
 The procedures for immediate tooth-supported
complete dentures are identical to those described ,
except that the coronal reduction of the selected
abutment teeth is done at the time the remaining teeth
are extracted.
 The teeth to Be retained are prepared on the master
cast to the approximate shape of the pending
abutment, and the remaining teeth are trimmed from
the cast in the usual manner.
 The endodontic treatment is completed during one or
more appointments before the immediate denture
insertion or just before the combined surgical-
prosthetic appointment.

50. • The need for refining the impression surface of the denture in the operated
on and abutment sites, by the addition of a treatment resin, is essential
because rapid tissue changes are to be anticipated.
• When healing has occurred and tissues and remodeling bone have achieved a
stable contour, additional coping preparation may be necessary with refitting
of the prosthesis in this area.

51. SUMMARY
Relatively short-term favorable outcomes with the
overdenture technique are well demonstrated and
endorse routine prescription of the technique.
Furthermore, the recent introduction of the
osseointegration technique created the possibility
of converting patients with maladaptive complete
dentures into ones with adaptive overdentures
when implants are used to stabilize “offending”
prostheses