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

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

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

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

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

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

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

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

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

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

Crown / Root Ratios

Attachment Retained Overdentures 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

Overdentures Attachment 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

Overdentures Attachment 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

Overdenture Evaluation 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

Direct Placement Placed by Dentist 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

Indirect Placement Placed by Laboratory 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

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