1. Overdentures
Dr Clarisse Ng

2. a removable partial or complete denture that covers and rests on one or more remaining natural teeth, roots, and/or dental implants

3. Why use an overdenture?
Extraction of entire dentitions resulted in residual ridge resorption. Occlusal forces of functional and parafunctional nature exert an adverse influence on the denture supporting tissues.
By retaining teeth, the treatment strategy is to share stress concentration between abutment teeth and denture supporting tissues.

4. Advantages
Maintenance of more residual ridge integrity. This results from improved stress distribution
Denture stability and retention can be enhanced.
“Natural feeling” – better occlusal awareness, biting force, neuromuscular control
Viable and simple alternative to complete denture
Application is virtually unlimited

5. Disadvantages Patient’s lack of oral hygiene motivation
Covered abutments are not conducive for maintaining a plaque free environment.
Inadequate space – potential weakness in acrylic resin denture base

6. Indications and treatment planning
Group 1 – patients with few remaining teeth that may be healthy or periodontally involved, coronally intact or morphologically compromised.
Treatment is usually straightforward
i. Analysis of articulated diagnostic casts
ii. Radiographs
iii. Determine potential abutment teeth’s restorative and endodontic requirements

7. Group 2 – patients who are diagnosed with a mutilated or severely compromised dentition.
Treatment is often defined by complexity, expense and time implications
i. Selected extractions may be carried out – retention of teeth with good alveolar support will preserve bone
ii. Retention of periodontally compromised teeth may affect periodontal status

8. Selection of abutment teeth
Periodontal and mobility status
- periodontally compromised teeth with horizontal bone loss are suitable
- vertical bone loss, coupled with Class 2 or 3 mobility are bad candidates. Slight mobility is not contraindication – favorable change in crown-root ratio after preparation.
- circumferential band of attached gingiva (1 mm) is a requirement for abutment selection

9. (2) Abutment location - anterior mandibular alveolar ridge appears to be most vulnerable to bone loss. Consider maintaining canines and/or premolars - same in maxilla, although incisors are also used. - clinical experience supports the recommendation of at least one tooth per quadrant. If this recommendation is exceeded, retained teeth should not be adjacent ones to minimize compromise in soft tissue health.

10. (3) Endodontic and prosthodontic status - anterior single rooted teeth are easier and less expensive to prepare. - the selected teeth can be reduced for technical convenience and treated with sealant restorations and fluoride applications.

11. Summary Abutment tooth must have healthy periodontal tissues
Reduction of the coronal portion of tooth to achieve a better crown-root ratio. Also to create space for placement of denture teeth.
Coverage of the tooth/root – amaglam or composite or gold coping . A simple, short, convex abutment preparation is the optimal root surface preparation. Preparation should taper towards occlusal or incisal surface
Provision of attachment mechanism – intracoronal or extracoronal, resilient or non-resilient
Motivated patient. Fluoride is prescribed for daily application to the inside of the overdenture.
Long term monitoring of abutment teeth
After 5-6 years, about 10% of overdenture abutment teeth were lost. The most frequent causes were periodontal disease (70%), caries (25%) and endodontic complications (5%)

12. Gold copings

15. Magnets

16. Tissue bar

21. Ball attachment

24. Advantages: low profile to reduce leverage on retaining abutments, easy to maintain, physiologic independent movement of abutments, easy to service

25. Bar and clip in anterior, ERA attachments posterior

27. ERA

28. Male Color Code:
Black fabrication male
White final male with light retention
Orange final male with moderate retention
Blue oversize male with heavy retention
Grey oversize male with very heavy retention
Yellow extra oversized male with more retention than grey
Red extra oversized male with more retention than yellow

29. Standard ERA 4.0 mm ERA-RV 3.5 mm Standard ERA ERA-RV

30. Locator

31. Stainless Steel Denture Cap with Black Processing Male
White Nylon Male (5lbs),
Pink Medium Retention Nylon Male (3lbs)
Blue Light Retention Male (1.5lbs)
Block-Out Spacer

32. If the divergence of any abutment is between 100 and 200, use the Extended Range Replacement Male which can accommodate a divergent abutment up to 200 (400 between multiple abutments)
Green – 4 lbs
Orange – 2 lbs
Red – 0.5 lbs

33. Low profile 3.17 mm 4.85 mm 5.82 mm 6.14 mm 6.22 mm Locator ERA Dal-Ro
O Ring
EDS

34. Locators torqued in to 35 Ncm

35. Processing males with housing placed intraorally
Processing males with housing placed intraorally. Check that this does not interfere with the denture. I used disclosing wax.

38. Locator tool

39. Questions?