What Is an Overdenture

1. What Is an Overdenture A complete denture that is supported and often retained by the underlying teeth or implants and tissue

2. Abutment teeth or implants may or may not be connected to the denture via attachments

3. Bars Copings Studs Magnets Implants Load bearing Overdenture Attachments Posts Teeth Non-Load-bearing Extraradicular Intraradicular Combinations ?????????????????????????????????

4. Bar joints Bar units Round Ovoid Square Rectangular Radicular: Extraradicular Studs, magnets, ERA Intraradicular Zaag, Zest, Sterns root anchor Overdenture Attachments Bars:

5. Objectives of the Program • Understand how overdentures preserve hard and soft tissue • Maintain proprioception • Understand the function of overdenture attachments and simplify attachment selection • Increasing crown/root ratios to preserve abutments • Hygiene maintenance

6. Carlson and Persson, Odontologist Revy, Sweeden 1967 Anterior mandible “average bone loss first year after extractions was 4mm” Tallgren, JPD,1972 “Bone loss continues for at least 25 years”

7. Natural dentition Complete dentures Overdentures 90% 59% 79% Dentures vs OverdenturesChewing Efficiency Rissin and House, JPD, 1978

8. Indications for Overdentures • Periodontal disease • Few remaining teeth • Insufficient crown/root ratios • Vertical space • Favorable path of insertion • Retention

9. Advantages of Overdentures • Maintenance of bone height around teeth by preserving roots • Attenuates resorption patterns of alveolar ridges • Gentler to the tissues • Increases crown/root ratios • Psychological security • Enhanced speaking ability • Maintains Proprioception

10. Disadvantages of Overdentures • Esthetic Considerations – Bulkiness • Root canal therapy • Increase space requirements: -interarch -interocclusal • Increase costs

11. Crown / Root Ratios

12. Attachment RetainedOverdentures All the advantages of Overdentures PLUS • Superior aesthetics • Increases proprioception • Stability and comfort • Rigidity or resiliency • Mechanical retention • Support • Increased psychological security and patient acceptance

13. OverdenturesAttachment Considerations Load Bearing Solid / Rigid • Transfers stress towards the retained roots or implants and away from the ridge • No vertical resiliency, some hinge or rotational resiliency • Shares the load of occlusion with the mucosal surface Magnets, Flexi ball, Dalbo Rotex, Bars

14. OverdenturesAttachment Considerations Non- Load Bearing Resilient • Transfers stress away from the retained roots or implants and towards the tissue • Vertical resiliency • Selected frequently Dalla Bona, Rotherman, Ceka, Uni Anchor, OSO, ORS, ERA, Bars

15. Partial Denture Present Tooth position Occlusion Mount casts to vertical dimension No Partial Denture Mount cast to vertical dimension Diagnostic denture wax up – reestablish occlusion Silicone matrix for space evaluation Overdenture Evaluation

16. Direct Placement • Male or female premanufactured attachment is cemented into root • Denture is made and inserted • Corresponding male or female attachment is inserted in root • Attachment is picked up directly in the overdenture with cold cure acrylic Placed by Dentist

17. Indirect Placement • Male or female attachment is cemented into root or may need to be cast onto coping • Corresponding male or female transfer analog is inserted into root attachment • Transfer impression is taken and models are poured with transfer in place • Laboratory processes denture with corresponding attachment in place Placed by Laboratory

18. Proceedures To Follow • 5 mm or more root remaining in bone • Stable perio • Mount study models – evaluate space required • Select OD attachment – obtain reference manuals • Begin denture proceedings • Root canal therapy • Decoronate roots, extractions, insert temporary denture – reline – allow time for healing • Prep tooth for attachment and cement attachment • Insert denture, make adjustments, post placement reline • Pick up male attachment in denture