What Is an OverdentureA complete denture that is supported and oftenretained by the underlyingteeth or implants and tissue

Abutment teeth or implantsmay or may notbe connected to the denture via attachments

Overdenture AttachmentsStudsBarsTeethImplantsMagnetsCopings PostsCombinationsIntraradicularExtraradicular?????????????????????????????????Load bearingNon-Load-bearing

Overdenture AttachmentsBar jointsBar unitsRoundOvoidSquareRectangularRadicular:ExtraradicularStuds, magnets, ERAIntraradicularZaag, Zest, Sterns root anchor

Bars:

Objectives of the ProgramUnderstand how overdentures preserve hard and soft tissueMaintain proprioceptionUnderstand the function of overdenture attachments and simplify attachment selectionIncreasing crown/root ratios to preserve abutmentsHygiene maintenance

Carlson and Persson, Odontologist Revy, Sweeden 1967Anterior mandibleaverage bone loss first year after extractions was 4mmTallgren, JPD,1972Bone loss continues for at least 25 years

Dentures vs Overdentures

Chewing EfficiencyNatural dentition

Complete dentures

Overdentures90%

59%

79%Rissin and House, JPD, 1978

Indications for OverdenturesPeriodontal diseaseFew remaining teethInsufficient crown/root ratiosVertical spaceFavorable path of insertionRetention

Advantages of OverdenturesMaintenance of bone height around teeth by preserving rootsAttenuates resorption patterns of alveolar ridgesGentler to the tissuesIncreases crown/root ratiosPsychological securityEnhanced speaking abilityMaintains Proprioception

Disadvantages of OverdenturesEsthetic Considerations BulkinessRoot canal therapyIncrease space requirements:-interarch-interocclusalIncrease costs

Crown / Root Ratios

Attachment RetainedOverdenturesAll the advantages of OverdenturesPLUSSuperior aestheticsStability and comfortMechanical retentionIncreased psychological security and patient acceptanceIncreases proprioceptionRigidity or resiliencySupport

OverdenturesAttachment Considerations

Transfers stress towards the retained roots or implants and away from the ridgeNo vertical resiliency, some hinge or rotational resiliencyShares the load of occlusion with the mucosal surface

Magnets, Flexi ball, Dalbo Rotex, Bars

Load BearingSolid / Rigid

OverdenturesAttachment Considerations

Transfers stress away from the retained roots or implants and towards the tissueVertical resiliencySelected frequentlyDalla Bona, Rotherman, Ceka, Uni Anchor, OSO, ORS, ERA, BarsNon- Load BearingResilient

Overdenture EvaluationPartial Denture Present Tooth positionOcclusionMount casts to vertical dimension

No Partial DentureMount cast to vertical dimensionDiagnostic denture wax up reestablish occlusionSilicone matrix for space evaluation

Direct PlacementMale or female premanufactured attachment is cemented into rootDenture is made and insertedCorresponding male or female attachment is inserted in rootAttachment is picked up directly in the overdenture with cold cure acrylic

Placed by Dentist

Indirect PlacementMale or female attachment is cemented into root or may need to be cast onto copingCorresponding male or female transfer analog is inserted into root attachmentTransfer impression is taken and models are poured with transfer in placeLaboratory processes denture with corresponding attachment in place

Placed by Laboratory

Proceedures To Follow5 mm or more root remaining in boneStable perioMount study models evaluate space requiredSelect OD attachment obtain reference manualsBegin denture proceedingsRoot canal therapyDecoronate roots, extractions, insert temporary denture reline allow time for healingPrep tooth for attachment and cement attachmentInsert denture, make adjustments, post placement relinePick up male attachment in denture