TOOTH SUPPORTED OVERDENTURES IN PROSTHODONTICS

Tooth supported overdentures in prosthodontic rehabilitation of an edentulous patient

1. TOOTH SUPPORTED OVERDENTURES
AND PRECISION ATTACHMENTS
MONICA
FINAL YEAR

2. CONTENTS
•Overdenture definition and Rationale for overdenture
•Advantages & Disadvantages and Indications & Contraindications
•Factors manipulating patient selection and Classification
•Precision attachments –Stud, Magnetic retainers and Bar attachments
•Factors influencing selection of abutment teeth
•Preparatory treatment
•Abutment preparation and Coping fabrication
•Impression of the denture
•Record bases and occlusion rims
•Recording maxillomandibular relations
•Trying the denture
•Laboratory Procedures
•Denture insertion
•Conclusion

3. OVERDENTURE
Any removable dental prosthesis that covers and rests
on one or more remaining natural teeth, the rootsof
natural teeth, and/or dental implants.
GPT-9
TYPES –
•Tooth supported overdenture
•Implant supported overdenture

4. RATIONALE FOR OVERDENTURE
•Roots –offers support for occlusal forces.
•Accelerated rate of bone resorption -prevented.
•Increases patients manipulative skills in handling the
denture (periodontal membrane is preserved, thus
proprioceptive impulses, part of myo-facial complex are
retained).

5. ADVANTAGES
•Preservation of residual alveolar ridge –
Periodontal attachments provides tensile stimulation conducive to bone
repair and maintenance.
•Superior patient’s acceptance
•Definitive vertical stop for the denture base
•Horizontal and torquingforces are minimized.
•Stability and support are increased –
Reduces the force of occlusion to the supporting tissues.
•Less trauma to supporting tissues.
•Fewer post insertion problems than conventional CD
•Increased biting force

6. DISADVANTAGES
•Caries susceptibility
•Periodontal disease around abutments.
•Bony undercuts (due to limited path of insertion)
•Encroachment of inter occlusal distance.
•Meticulous oral hygiene is required.
•Time consuming
•Technique sensitive

7. INDICATIONS
•Patient with few natural remaining teeth.
•Poor prognosis for routine complete denture.
•Congenital or acquired intra oral defects.
•Mandibular arch where loss of bone is more rapid.
•Edentulous maxilla opposing intact mandibular dentition.
•Post traumatic or post surgical cases.
•Severe attrition and loss of vertical dimension.
•Young patient
•Cleft palate causing large free way space.
•Hypodontia

8. CONTRAINDICATIONS
•High caries index.
•Poor oral hygiene.
•Poor prognosis of abutment.
•Reduced inter-arch space.
•Undercuts.
•Sufficient attached gingiva not present.
•Where endodonticand periodontictreatment can not beperformed
satisfactorily.
•Grade III mobility

9. FACTORS MANIPULATING PATIENT SELECTION
•Possibility of FDP or RPD
•Endodontic therapy
•Periodontal condition of abutment teeth
•Caries
•Young patients
•Location of abutment teeth
•Economics

10. CLASSIFICATION
ACCORDING TO METHOD OFABUTMENT PREPARATION(Heartwell)
OVER DENTURE
TOOTH SUPPORTED
NON COPING COPING
SHORT
LONG
ATTACHMENTS
STUD
BAR
MAGNETS
IMPLANT SUPPORTED

11. BASED ON TYPE OF DENTURE (Brewer and Morrow)
IMMEDIATE
TRANSITIONAL / INTERUPT
DENTURE
REMOTE / PERMANENT DENTURE

12. NON COPING ABUTMENTS
Selected tooth abutments -reduced to a
coronal height of 2-3 mm
Contoured to a convex or dome shaped
surface
Most teeth requiredendodontic therapy
Finally -amalgam or composite type
restoration

13. ABUTMENTS WITH COPINGS
Cast metal coping with a dome shaped surface and a chamfer finish
line at the gingival margin are fabricated and cemented.
Short coping
Long coping

14. SHORT CAST COPINGS
2-3mm above ridge crest
Normally require endodontic therapy

15. LONG CAST COPINGS
4-8 mm long -conservative
reduction of coronal tooth structure
is done.
Result in long ellipsoidal shaped
coronal coping and a larger crown
root ratio.
Require a greater level of osseous
support and vertical dimensions.

16. ABUTMENT WITH ATTACHMENTS
Attachments are small precision devices.
Objective –To improve retention of denture base.
Most attachments are secured to abutment by a cast
coping.
Consists of two parts –
•Patrix(male/key)
•Matrix(female/keyhole)

17. Requirements
Patients should have a low caries index.
Perform proper home care.
Sound periodontal health.
Proper bone support
1. Stud attachments
2. Magnetic retainers
3. Bar attachments

18. 1. STUD ATTACHMENTS
Simplest of all attachments
Consists of two parts –
•The stud (male component)
usually attached to metal
coping cemented over
prepared abutment
•Housing (female component)
embedded in the fitting
surface of over denture

19. EXTRARADICULAR STUD ATTACHMENT
Patrixelement project from the root surface.
The stud is attached to the metal copingcemented over the
preparedabutment, while thehousing is embedded in the
fitting surface ofdenture.
•Gerber
•Ceka
•Rotherman

20. GERBER ROTHERMAN
CEKAREVAX
(EXPLODED VIEW)

21. INTRARADICULAR STUD ATTACHMENT
Patrixelement forms part of denture base and engage depression within
abutment contour.
The stud is attached to the fitting surfaceof the denture and the housing is
incorporated in the abutment.
•Zest Anchor

23. ALIGNMENT OF STUD ATTACHMENTS
•Attachmentsshould be aligned to each
other.
•The alignment of stud attachments with
one another <10°.
•The alignment of the attachment with
the denture path of insertion.
•The taller the attachment, the more
difficult the alignment may be.

24. NUMBER OF STUD ATTACHMENT
•One stud attachment on either side of the arch -
remaining roots can be covered by simple copings.
•Increasing no.of attachments = may increase stability
•Increasing no. of attachments = weaker denture
•Two stud attachments on adjacent roots -complicate
hygiene measures and also weaken the denture base.

26. 2. MAGNETIC RETAINERS
oDetachable keeper element
Made of stainless steel that is fixed to abutmentteeth by
Cementing
Screwing
oDenture retention element
Has paired, cylindrical Neodymium-Iron-Boron magnets
axially magnetized and arranged with theiropposite poles
adjacent.

27. •Small, strong mini magnets
•One of poles cemented in the prepared
cavityin endodontically treated abutment
and theother attached to denture base.
•Examples –Magfit600 unit and
Innovadent(Gillings) system.

28. 3. BAR
oA bar contoured to connect abutment teeth
together, run parallel & overlie residual ridge
oPreformed metal or plastic retention clips.
The purpose of using bars are:
•Splinting of abutment teeth
•Retention and support of prosthetic appliance
Vertical and buccolingual space requirements limit
their applications.
Demand more oral hygiene maintenance.

29. BAR ATTACHMENTS
BAR JOINTS
(slight movement)
Utilize support
both from
residual ridge
and abutment.
Thus tooth
tissue born.
SINGLE SLEEVE
MULTIPLE
SLEEVE
BAR UNITS
(rigid)
Transmit
occlusal stresses
totally to
abutments.
Thus tooth
borne.

31. FACTORS INFLUENCING SELECTION OF ABUTMENT
TEETH
PERIODONTAL STATUS
MOBILITY
LOCATION
ENDODONTIC CONSIDERATIONS
COST

32. PERIODONTAL STATUS AND MOBILITY
•Ideally tooth -minimalmobility, have acceptable bone
supportand beresponsive to periodontal therapy.
•Circumferential band of attached gingiva
•Compromised teeth with good treatmentprognosis are
suitable candidates even whenhorizontal bone loss is
present.
•Slight tooth mobility with horizontal boneloss –not
contraindicated
•Vertical bone loss particularly accompaniedby Class II or
III mobility excludes toothselection.

33. ABUTMENT LOCATION
•Ideal : Two teeth per quadrant (stress is distributed over a rectangular
area).
•Tripodis next most favorable form for support and stability.
•Clinical experience recommends at least one tooth per quadrant.
•Isolated teeth are preferred -inter dental areas are difficult to clean and
susceptible to gingivitis.
•Canine and premolars -best overdenture abutments.
•In maxilla –Central Incisors–Ideal overdenture abutments (protects pre
maxilla)
•Canines are next (Longest root).
•Lateral incisors (widely spaced, facilitating plaque control).

34. ENDODONTIC STATUS
•Preserve teeth that are alreadyendodontically treated.
•Usually anterior teeth are preferred -easier to prepare and
economical too.
•Pulpal recession to the extent ofcalcification has occurred ,
endodontictreatment usually can be avoided.
•Maintain adequateoral hygiene to prevent abutment loss.
•Patients must clean all exposed dentin anduse 0.4% stannous
fluoride daily.

35. PREPARATORY TREATMENT
FOLLOWING SEQUENCE OF TREATMENT CAN BE USED AS A
GENERAL GUIDE BUT MAY NOT BE SPECIFICALLY APPLICABLETO
ALL PATIENTS:
1.Construct an immediate treatment clasplessdenture-Replaces
missing and hopelesslyinvolved teeth for esthetic reason and
retain jawrelations.
2.Remove hopeless teethand insert the removableprosthesis.
3.During the healing period, institute theperiodontic and
endodontic treatment.

36. ABUTMENT PREPARATION
•Remove sufficient tooth structure to providefavorable root-crown
ratio.
•Reduce the crown length up to 2 mm above thegingival crest or
extend a chamber type marginslightly beneath free gingival margin.
•Taperthe preparation in occlusogingivaldirection.
•Consequently optimal abutment preparationis achieved that has
following features:
SimpleShortConvexDome shapedChamfer finish line

37. Maxillary root filled teeth

38. COPING FABRICATION
INSTRUCT PATIENT FOR HOME CARE
OF ABUTMENT TOOTH
CEMENT THE POLISHED COPING TO
THE TOOTH
CAST THE COPING
POUR A DIE
ABUTMENT IMPRESSION

40. IMPRESSION OF THE DENTURE
Follows the same technique that is used in constructing a
conventional complete denture.
•PRELIMINARY IMPRESSION
•BORDER MOLDING
•FINAL IMPRESSION

41. RECORD BASES AND OCCLUSION RIMS
Apply one thickness of
baseplate wax to the
abutments, leaving occlusal
surface exposed.
Seat the bearing
in the concavity
and seal it in
place with wax.
Eliminate
undercuts
Construct a
stable record
base
Attach wax
occlusion rims to
the record base

42. RECORDING MAXILLOMANDIBULAR RELATIONS
•A face bow transfer is used to relate the maxillary cast to thearticulator.
•Jaw relations and arrangement of teeth for phonetics areverified at the time of
try in.
TOOTH SELECTION
OPPOSING ARCH
TEETH
ARTIFICIAL TEETH
Gold occlusal surfaces Gold or acrylic resin, preferably
gold occlusal surfaces
Restored with
porcelain
Porcelain
Natural teeth Gold occlusalsare preferred,
otherwise acrylic.

43. TRYING THE DENTURE
•Verify jaw relation records
•Make eccentric jaw relation records and adjust the
articulator.
•Assure esthetic acceptability by the patient.
•Verify phonetic acceptability.

44. LABORATORY PROCEDURES
•CONTOUR THE WAX
•FLASK THE DENTURE
•ELIMINATE THE WAX
•PRAPARE RESIN
•PACKING

45. DENTURE INSERTION
•Review instruction in denture use and
care.
•Use pressure disclosing paste to locate
contacts between female and male
members.
•Evaluate the tissue side of denture
base and borders for pressure areas
and over extensions.
•Perfect the occlusion by remounting
and selective grinding.
•Place patient on recall system.

46. CONCLUSION
Overdentures can offer an alternative treatment
modality compared to conventional dentures but a
successful outcome requires careful case selection,
treatment planning, and individualized maintenance.

47. REFERENCES
•Essentials of complete denture prosthodontics –Sheldon Winkler 2
nd
edition
•Prosthodontic treatment for edentulous patients –ZarbBolender13
th
edition
•Textbook of complete dentures –Heartwelland Arthur O. Rahn5
th
edition
•Overdentures Made Easy –Harold W. Preiskel