Overdenture is a favored treatment modality for elderly patients with few remaining teeth. Roots maintained under the denture base preserve the alveolar ridge, provide sensory feedback and improve the stability of the dentures. Furthermore, the use of copings and precision attachments on the remaining teeth enhances the retention of the denture. This clinical report describes a novel method of fabricating a tooth supported overdenture retained with custom made ball attachments using orthodontic separators as a female component. Customized ball attachments with orthodontic separators are a simple and cost effective alternative treatment to the use of prefabricated attachments for enhancing the retention of tooth supported overdentures.

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DR.NOOR ADDEEN ABO ARSHEED
Clinical Lecturer and Specialist Prosthodontist
Head of LUC Dental Center
BDS, HD Prostho, MDS , DOI (Germany)
NBDE (USA) , FICOI (USA).
LINCOLN UNIVERSITY COLLEGE
Facebook.com/AboarsheedNasa

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OVERDENTURES
Part 1

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introduction :
Occasionally, a patient with few remaining natural teeth may
present himself at the clinics.
Most often they are advised total extraction and construction of
conventional complete dentures.
However, it is possible to preserve these remaining teeth (after
suitable treatment) and construct a denture over them.
Thus, the overdenture uses one or more modified natural teeth for
retention, support and stability.

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Synonyms:
These dentures have been called by a variety of names tooth
supported dentures, overlay dentures, onlay dentures,
overdentures, telescoped dentures, hybrid dentures, biologic
dentures, coping prosthesis and superimposed dentures.

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RATIONALE

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RATIONALE
Why not extract all remaining teeth and plan a complete
denture?
The teeth and the alveolar bone are closely interlinked. Without the
teeth, the alveolar bone tends to atrophy and resorb. The longer the
teeth remain in the alveolar bone the longer it is preserved. Thus, it
is important to preserve the alveolar bone for as long as possible.

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RATIONALE
Thus, the overdenture is a logical method for use in preventive
prosthodontics. Preserving the remaining natural teeth not only
preserves the alveolar bone, but also gives the patient better
function and control over the dentures because of the presence of
nerve receptors in the root.

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RATIONALE
Why not leave the remaining teeth and plan an RPD?
An RPD (removable partial denture) takes part of its support from
the natural teeth. A large RPD utilizing a few remaining teeth for
support and retention could result in excessive stresses on those
teeth.

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RATIONALE
Over a period of time mobility and periodontal breakdown could
ensue resulting in failure of the abutments.

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RATIONALE
Why shorten the teeth?
Shortening the natural tooth changes the crown root ratio This
reduces the lateral stresses. It also reduces lever action on the
tooth. The load is now in a more occlusal direction which is better
tolerated by the tooth. The complete denture resting on these
shortened teeth exerts largely vertical forces directed towards the
bone which are better tolerated by the teeth.

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RATIONALE
Reducing the crown ratio also forms the basis of using mobile teeth
which would have been indicated for extraction. Reducing the crown-
root ratio reduces the mobility of these teeth and improves their
prognosis.

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DEFINITION
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 (GPT-8).

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CLASSIFICATION
Based on method of abutment preparation:
1. Non coping
With endodontic therapy
Without endodontic therapy
2. Coping
With endodontic therapy (short coping)
Without endodontic therapy (long coping)
3. Attachments

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CLASSIFICATION

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CLASSIFICATION
Based on type of overdenture
1. Immediate overdenture
2. Transitional overdenture
3. Remote overdenture

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CLASSIFICATION
Noncoping abutments with endodontic treatment
Most teeth require endodontic therapy because of a lack of
interocclusal space selected root abutments are reduced to a
coronal height of 2 to 3 mm and then contoured to a convex or
dome shaped surface. The root canal access opening is
restored with amalgam or composite.

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CLASSIFICATION

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CLASSIFICATION
Noncoping abutments without endodontic treatment
This type is given only if there is sufficient interocclusal space
The pulp should have receded sufficiently so that the reduced
teeth are not sensitive
It is usually indicated in patients with partial anodontia and
severe attrition .

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CLASSIFICATION
Coping abutments
A coping is a thin covering. The abutment teeth may be covered
with copings to give better protection against caries.
Cast metal copings with dome shaped surfaces and chamfer
finish lines at the gingival margins are made and cemented.

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CLASSIFICATION
short cast copings
These are 2 to 3 mm long and normally require endodontic treatment
because of the risk of pulp exposure. The coping is attached by
means of a post in the root canal.

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CLASSIFICATION

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CLASSIFICATION
Long cast copings
These are about 5 to 8 mm long and are given in an attempt to avoid
endodontic treatment. They also require greater bone support.

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CLASSIFICATION

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CLASSIFICATION
Abutments with retentive devices
In cases where increased retention is required for the denture,
special retentive devices may be attached to the abutment and to the
inner surface of the denture.

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CLASSIFICATION

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CLASSIFICATION
Immediate, transitional and remote overdentures
The immediate overdenture is constructed for insertion
immediately after extraction of some natural teeth.

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CLASSIFICATION
A transitional overdenture is obtained by converting an existing
removable partial denture into an overdenture.

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CLASSIFICATION
The remote overdenture is constructed after the extraction of the teeth,
endodontic therapy, cast copings or any other procedure.

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INDICATIONS FOR
OVERDENTURES
1 . Patients with poor prognosis for routine complete dentures.
• High palatal vault
• Xerostomia.
• Poor mandibular ridges
• When high rate of resorption is expected
• When opposing natural teeth are present
• Smaller dental arches

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INDICATIONS FOR
OVERDENTURES
2. Patients with congenital or acquired intraoral defects.
• Partial anodontia
• Microdontia.
• Amelogenesis imperfecta
3. In case of severe attrition, vertical height can be restored with an
overdenture.
4. Very young patients facing total extraction.
5. Low caries index and good oral hygiene

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INDICATIONS FOR
OVERDENTURES

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CONTRAINDICATION
1. High caries index and poor oral hygiene
2. When the abutments have a doubtful prognosis
• When endodontic treatment is not possible
• When periodontal therapy and reduction of crown-root ratio does
not improve periodontal health
3. Uncooperative, terminally ill, or senile patients.

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ADVANTAGES
1. Preservation of the alveolar bone. Presence of the abutment teeth
reduce resorption.
2. Preservation of the proprioception. Oral function and feeling is
improved because of the proprioceptive feedback from receptors in
the root.
3. Improved support because of the abutment teeth.

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ADVANTAGES
4. Improved retention. Retention devices can be attached to the
abutment teeth when increased retention is needed
5. Less psychological trauma as patients are able to retain their
original teeth
6. Can be converted to a routine complete denture in case of
abutment failure

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DISADVANTAGES
1. High risk of caries especially for the noncoping abutments due to
coverage of the teeth by the denture .
2. Risk of periodontal problems due to improper care by the patient
3. High initial cost due to the castings, precision attachments,
preceding endodontics, periodontal and other therapies.

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DISADVANTAGES
4. Long bony undercuts are often found near the abutment teeth. So
tissue injury may result in ,during insertion and removal of the
overdenture.
5. Tooth arrangement is difficult in some cases because of the
reduced interocclusal distance.

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THE END
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