Supradentalne proteze - indikacije, kontraindikacije, tretman

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OVERDENTURESOVERDENTURES

Indications, Contraindication andIndications, Contraindication and

Treatment ProcedureTreatment Procedure



INTRODUCTION INTRODUCTION

DEFINITIONS DEFINITIONS DEVELOPMENT DEVELOPMENT

RATIONALERATIONALE

CLASSIFICATION CLASSIFICATION

ADVANTAGES ADVANTAGES

INDICATIONS INDICATIONS

CONTRAINDICATION CONTRAINDICATION

TREATMENT PROCEDURE TREATMENT PROCEDURE CONCLUSION CONCLUSION

IMPLANT OVERDENTURE IMPLANT OVERDENTURE



INTRODUCTION INTRODUCTION

Overdenture, a complete or Overdenture, a complete or partial prosthesis constructedpartial prosthesis constructedover existing teeth or rootover existing teeth or rootstructure, is not a new concept instructure, is not a new concept ina technical approach to aa technical approach to a

prosthetic problemprosthetic problem Indeed its use dates back over Indeed its use dates back over

100 yrs and it is one that has100 yrs and it is one that hasbecome increasingly morebecome increasingly morepopular since the emphasis of popular since the emphasis of

prevention in dentistryprevention in dentistry Preventive prosthodonticsPreventive prosthodontics

emphasizes the importance of emphasizes the importance of any procedure that can delay or any procedure that can delay or eliminate future prosthodonticeliminate future prosthodonticproblemsproblems



DEFINITIONS DEFINITIONS

A removable partial denture or complete denture A removable partial denture or complete denturethat covers and rests on one or more remainingthat covers and rests on one or more remainingnatural teeth, the roots of natural teeth and/or natural teeth, the roots of natural teeth and/or dental implantsdental implants

A prosthesis that covers and is partially A prosthesis that covers and is partiallysupported by natural teeth, natural tooth, rootssupported by natural teeth, natural tooth, rootsand/or dental implantsand/or dental implants

Also called as overlay dentures / overlay Also called as overlay dentures / overlay

prosthesis / superimposed prosthesisprosthesis / superimposed prosthesis GPT – 8 th ed



An overdenture is a denture that may be An overdenture is a denture that may be

supported by soft tissue, bone, the root of asupported by soft tissue, bone, the root of atooth, or a modified toothtooth, or a modified tooth

Also called as biologic denture, telescopes Also called as biologic denture, telescopes

denturedentureHeartwell



DEVELOPMENT DEVELOPMENT

The idea of leaving roots of natural teeth to support anThe idea of leaving roots of natural teeth to support anoverdenture is far from new; even in 1856, Ledger hadoverdenture is far from new; even in 1856, Ledger haddescribed a prosthesis resembling an overdenture whichdescribed a prosthesis resembling an overdenture whichwas referred to as ‘plates covering fangs’ and this becamewas referred to as ‘plates covering fangs’ and this becamethe title of a paper published by Atkinson 5 yr later the title of a paper published by Atkinson 5 yr later

In 1861, conference in Conneccticut produced increaseIn 1861, conference in Conneccticut produced increaseawareness of the value such roots might play inawareness of the value such roots might play insupporting a covering denturesupporting a covering denture

Evans by 1888 described a method of using roots actuallyEvans by 1888 described a method of using roots actuallyto retain restorationsto retain restorations

Essig in 1896 and Peeso around the same timeEssig in 1896 and Peeso around the same timeprescribed a telescoic-like copingprescribed a telescoic-like coping

William Hunter mentioned the necessity to devitalize mostWilliam Hunter mentioned the necessity to devitalize mostof the roots employed for prosthesisof the roots employed for prosthesis



In 1967 and 1969 Talligren showed that over a 7 yr periodIn 1967 and 1969 Talligren showed that over a 7 yr periodthe reduction of anterior ridge height of the mandible is 4the reduction of anterior ridge height of the mandible is 4times than that of the maxillary edentulous ridge. Thesetimes than that of the maxillary edentulous ridge. These

findings were corrobrated by Atwod and Coy (1972)findings were corrobrated by Atwod and Coy (1972) Crum and Rooney(1978) reported a 4 yr study and claimedCrum and Rooney(1978) reported a 4 yr study and claimed

that the retention of mandibular canines of overdenturesthat the retention of mandibular canines of overdentureshelped preserve the remaining edentulous ridgehelped preserve the remaining edentulous ridge

In 1986 a study reported on 1739 implants placed in theIn 1986 a study reported on 1739 implants placed in themandibular symphysis of 484 patients. The implants weremandibular symphysis of 484 patients. The implants wereloaded immediately and restored with bars and overdentureloaded immediately and restored with bars and overdenturewith clips as retention and overall success rate was 94%with clips as retention and overall success rate was 94%

Dotansky (1993) publlished a survey of patients sufferingDotansky (1993) publlished a survey of patients sufferingfrom mandibular alveolar ridge atrophy who had beenfrom mandibular alveolar ridge atrophy who had been

treated with overdentures supported by ball attachments andtreated with overdentures supported by ball attachments andthe success rates of the individual implants 97% and of thethe success rates of the individual implants 97% and of thedentures were100%dentures were100%



RATIONALERATIONALE

It maintains teeth as part of the residual ridgeIt maintains teeth as part of the residual ridge This givesThis givesthe patient a denture that has far more support than anythe patient a denture that has far more support than anyconventional appliance.conventional appliance.

A decrease in the rate of resorptionA decrease in the rate of resorption Alveolar bone exists Alveolar bone exists

as a support for teeth. If the teeth are removed the alveolar as a support for teeth. If the teeth are removed the alveolar process begins a rate of resorption consistent with the length of process begins a rate of resorption consistent with the length of time the teeth have been missing .By retaining the mandibular time the teeth have been missing .By retaining the mandibular canines in the use of an over-denture, the resorption of thecanines in the use of an over-denture, the resorption of thealveolar bone surrounding the teeth was reduced by eightalveolar bone surrounding the teeth was reduced by eighttimes.times.

It also helps in an increase in the patients manipulativeIt also helps in an increase in the patients manipulativeskills in handling the dentureskills in handling the denture with the preservation of thewith the preservation of theteeth for an over-denture there is also the preservation of theteeth for an over-denture there is also the preservation of theperiodontal membrane that surrounds these teeth. Thisperiodontal membrane that surrounds these teeth. Thispreserves the proprioceptive impulses supplied by thepreserves the proprioceptive impulses supplied by the

periodontal membrane..periodontal membrane..



REQUIREMENTSREQUIREMENTS

Maintenance of healthMaintenance of health the most important aspect of thethe most important aspect of theover-denture is the maintenance of the health of the underlyingover-denture is the maintenance of the health of the underlyingtooth structures without which the over-denture cannot sustain.tooth structures without which the over-denture cannot sustain.

Reduction in crown-to-root ratioReduction in crown-to-root ratio The reduction of the crownThe reduction of the crownhas an immediately favourable effect on tooth mobility becausehas an immediately favourable effect on tooth mobility becauseof the decrease in the length of the lever arm delivering theof the decrease in the length of the lever arm delivering the

torque to the mobile tooth.torque to the mobile tooth. Basal seat tissueBasal seat tissue A well fitting basal seat is essential to A well fitting basal seat is essential to

distribute the load over as wide an area as possible.distribute the load over as wide an area as possible. Simplicity of constructionSimplicity of construction The appliance should beThe appliance should be

relatively simple to construct and maintain.relatively simple to construct and maintain.

Ease of manipulationEase of manipulation frequently with the use of retainingfrequently with the use of retainingdevices the over-denture becomes a struggle for the patient todevices the over-denture becomes a struggle for the patient toinsert and remove. This should not be the case because aninsert and remove. This should not be the case because anunwanted force could seriously damage the base or theunwanted force could seriously damage the base or theabutment tooth therefore the design should be kept simple toabutment tooth therefore the design should be kept simple to

avoid such problems.avoid such problems.



INDICATIONSINDICATIONS

It should be considered for patients who face the loss of theIt should be considered for patients who face the loss of theremaining natural adult dentition. Therefore younger theremaining natural adult dentition. Therefore younger thepatient greater the indication.patient greater the indication.

In cases where the retention is difficult to obtain such as:In cases where the retention is difficult to obtain such as:

Xerostomia or sialorrheaXerostomia or sialorrhea Absence of alveolar residual ridge Absence of alveolar residual ridge Loss of maxilla and partial loss of mandibleLoss of maxilla and partial loss of mandible congenital deformity eg cleft palatecongenital deformity eg cleft palate For patients with a poor prognosis for complete dentures.For patients with a poor prognosis for complete dentures.

High palatal vault and ridge slopeHigh palatal vault and ridge slope Poorly defined sublingual fold spacePoorly defined sublingual fold space Posterior Open occlusal relationship in cases of for eg.,Posterior Open occlusal relationship in cases of for eg.,

cleidocranial dysplasia, hpothyroidism, hypoparathyroidismcleidocranial dysplasia, hpothyroidism, hypoparathyroidism66



In class III tongue positionIn class III tongue position Knife edged ridge that will provide inadequate support.Knife edged ridge that will provide inadequate support. When pronounced vertical overlap of the anterior teeth isWhen pronounced vertical overlap of the anterior teeth is

required to produce good esthetic results.required to produce good esthetic results. Unilateral over denture can be given to provide a goodUnilateral over denture can be given to provide a good

function and esthetics a large amount of bone and soft tissuefunction and esthetics a large amount of bone and soft tissuehave been lost on one side of the arch.have been lost on one side of the arch.

Patients with badly worn out teeth.Patients with badly worn out teeth. When complete denture will be opposed by retainedWhen complete denture will be opposed by retained

mandibular anterior teeth preventing (combination syndrome).mandibular anterior teeth preventing (combination syndrome).

Therapeutics in the form of insitu irradiation (Mobermott &Therapeutics in the form of insitu irradiation (Mobermott &Rosenberg (1963)Rosenberg (1963)



CONTRAINDICATIONSCONTRAINDICATIONS

Un co-operative and under motivated patients who insists onUn co-operative and under motivated patients who insists onremoval of his remaining teeth. Any indication of patient who willremoval of his remaining teeth. Any indication of patient who willnot co-operate in oral hygiene and regular office procedures, recallnot co-operate in oral hygiene and regular office procedures, recallfor adjustments which is required to maintain the remaining teethfor adjustments which is required to maintain the remaining teethand the supporting tissue in a state of health.and the supporting tissue in a state of health.

Psychologically some patients cannot accept any type of Psychologically some patients cannot accept any type of

removable denture.removable denture. Mentally and physically handicapped patients for whom plaqueMentally and physically handicapped patients for whom plaque

control and good oral hygiene are difficult.control and good oral hygiene are difficult. When a patient cannot economically afford.When a patient cannot economically afford. Periodontal Consideration:Periodontal Consideration: Periodontal inflammation, pocket formation, bony defects, andPeriodontal inflammation, pocket formation, bony defects, and

poor zone of attached gingiva must all be eliminated beforepoor zone of attached gingiva must all be eliminated beforecommencing the treatment. The deleterious effect of the over commencing the treatment. The deleterious effect of the over denture on the periodontium can be minimized of the over denturedenture on the periodontium can be minimized of the over dentureon the periodontium can be minimized if one begins with anon the periodontium can be minimized if one begins with anoptium state and the patient follows a meticulous home careoptium state and the patient follows a meticulous home careprogramme with frequent recall.programme with frequent recall.



Contra indications for using periodontally involved teeth.Contra indications for using periodontally involved teeth.

Class III mobility due to the loss of alveolar bone that connot beClass III mobility due to the loss of alveolar bone that connot becorrected.corrected.

Soft tissue and osseous defects which are not correctable bySoft tissue and osseous defects which are not correctable bysurgery.surgery.

Failure to establish a sufficient zone of attached gingiva byFailure to establish a sufficient zone of attached gingiva bymucogingival or grafting procedure.mucogingival or grafting procedure.

Excessive reduction of the adjacent residual alveolar ridge as aExcessive reduction of the adjacent residual alveolar ridge as aresult of elimination of osseous defects for the establishment of result of elimination of osseous defects for the establishment of normal architecture.normal architecture.



Contra indications for Endodontic Treatment:Contra indications for Endodontic Treatment:

Vertical fracture of the root (or) roots.Vertical fracture of the root (or) roots. Mechanical perforation of the root canal.Mechanical perforation of the root canal. Internal resorption that has perforated through the side of theInternal resorption that has perforated through the side of the

root.root. Broken instrument in the root canal.Broken instrument in the root canal.

Horizontal fracture of the root below the bony crest.Horizontal fracture of the root below the bony crest. Teeth that are grossly malposed will be difficult to useTeeth that are grossly malposed will be difficult to use

especially posterior teeth that are tilted more than 25°.especially posterior teeth that are tilted more than 25°. Single rooted teeth with only one canal that is easilySingle rooted teeth with only one canal that is easily

negotiable are the best candidates although multirooted teethnegotiable are the best candidates although multirooted teethcan also be used. A2 to 4 week interval before commencingcan also be used. A2 to 4 week interval before commencingfurther treatment on the tooth is helpful to determinefurther treatment on the tooth is helpful to determineendodontic complication if any.endodontic complication if any.



ADVANTAGESADVANTAGES

Apart from theApart from the Preservation of alveolar bone and preservationPreservation of alveolar bone and preservationof proprioceptive response, it also provides Support andof proprioceptive response, it also provides Support andretention.retention.

It is also a simple approach to the compromised patients withIt is also a simple approach to the compromised patients with

Cleft palateCleft palate

Partial anodontiaPartial anodontiaMicrodontiaMicrodontia

Patient acceptance – they experience a striking improvement inPatient acceptance – they experience a striking improvement infunction and esthetics while still maintaining some of their ownfunction and esthetics while still maintaining some of their ownteethteeth



Maintenance of arch formsMaintenance of arch forms

Convertibility – the over denture is designed in such a way thatConvertibility – the over denture is designed in such a way thatif for some reason the remaining teeth or root stumps has toif for some reason the remaining teeth or root stumps has tobe extracted the over-denture can be readily converted tobe extracted the over-denture can be readily converted toaccept the alteration.accept the alteration.

Cost – the initial cost may be a little higher but when comparedCost – the initial cost may be a little higher but when comparedover a period of time the low percentage of remakes and theover a period of time the low percentage of remakes and thealternative treatment of extensive fixed and removablealternative treatment of extensive fixed and removableprosthesis, the cost of an over-denture is favorableprosthesis, the cost of an over-denture is favorable

Ease in construction and maintenance.Ease in construction and maintenance.

Lower cost when compared to R.P.D.Lower cost when compared to R.P.D.



DISADVANTAGESDISADVANTAGES

Over denture treatment is more expensive thanOver denture treatment is more expensive thanconventional denture because of periodontal andconventional denture because of periodontal andendodontic therapy and the subsequent restoration of endodontic therapy and the subsequent restoration of teeth with gold coping.teeth with gold coping.

Bulkier than F.P.D. (or) R.P.D.Bulkier than F.P.D. (or) R.P.D.

If oral hygiene is not maintained properly, patient’sIf oral hygiene is not maintained properly, patient’ssusceptible tosusceptible to cariescaries andand periodontal diseaseperiodontal disease

Bony under cuts may cause either over contouring or Bony under cuts may cause either over contouring or under containing of the denture.under containing of the denture.

Encroachment of inter occlusal distance.Encroachment of inter occlusal distance. Esthetics.Esthetics.

In many cases, owing to lack of available spaceIn many cases, owing to lack of available spacesections of the over denture base are quite thin. If metalsections of the over denture base are quite thin. If metalreinforcement is not used, fracture of the base andreinforcement is not used, fracture of the base and

prosthetic teeth is common.prosthetic teeth is common.



Criteria for Patient selectionCriteria for Patient selection

Patients who are psychologically acceptable as CD patientsPatients who are psychologically acceptable as CD patientscan be candidates for submucosal vital root retention.can be candidates for submucosal vital root retention.

Should have a normal response to accepted clinical vitalityShould have a normal response to accepted clinical vitality

test.test. Should show at least 3mm of alveolar bone support onShould show at least 3mm of alveolar bone support onradiographic examination.radiographic examination.

Should be located within the area of the alveolar ridgesShould be located within the area of the alveolar ridgesmost affected by ridge resorption following tooth removal.most affected by ridge resorption following tooth removal.



Two major groups of patients who benefit from the over-Two major groups of patients who benefit from the over-dentures are.dentures are.

Group 1Group 1 Comprises patients with few remaining teeth that may beComprises patients with few remaining teeth that may be

healthy or with reversible periodontal disease, that arehealthy or with reversible periodontal disease, that arecoronally intact or malpositioned or morphologicallycoronally intact or malpositioned or morphologicallycompromised.compromised.

Before commencing the treatment carry outBefore commencing the treatment carry out Analysis of articulated diagnostic casts which helps to Analysis of articulated diagnostic casts which helps to

determine the potential abutment teeth’s restorative anddetermine the potential abutment teeth’s restorative andEndodontic requirements in the context of the proposed over-Endodontic requirements in the context of the proposed over-denture design.denture design.

Full mouth radiographsFull mouth radiographs

Group IIGroup II Diagnosed with so called multilated or severelyDiagnosed with so called multilated or severely

compromised dentitions. These patients appear to be headingcompromised dentitions. These patients appear to be headingin an edentulous direction.in an edentulous direction.



According toAccording to HAROLDHAROLD

Types of over-dentures areTypes of over-dentures are

TransitionalTransitional

The Transitional over denture consists of a modification of The Transitional over denture consists of a modification of the partial denture which the patient is already wearing, tothe partial denture which the patient is already wearing, toreplace further lost teeth or to cover the roots of over-denturereplace further lost teeth or to cover the roots of over-dentureabutments once the teeth have been cut down.abutments once the teeth have been cut down.

Training denturesTraining dentures

Strictly speaking, these are not over-dentures, but they doStrictly speaking, these are not over-dentures, but they dohave many applications in over-denture techniques. Suchhave many applications in over-denture techniques. Suchdentures are commonly employed to replace hopeless posterior dentures are commonly employed to replace hopeless posterior teeth once they have been extracted.teeth once they have been extracted.

Immediate-replacement over-denturesImmediate-replacement over-dentures

They are constructed before the last remaining teeth areThey are constructed before the last remaining teeth areextracted and the over-denture abutments prepared. A trainingextracted and the over-denture abutments prepared. A trainingdenture is often converted to an immediate replacement over denture is often converted to an immediate replacement over denture that may with judicious relining be employed for severaldenture that may with judicious relining be employed for severalmonths or years. Even when they are replaced such prosthesismonths or years. Even when they are replaced such prosthesismay serve as spare dentures later onmay serve as spare dentures later on



Definitive prosthesesDefinitive prostheses Usually constructed at least 6 months following extraction of Usually constructed at least 6 months following extraction of

the last teeth and the preparation of the over denture abutmentsthe last teeth and the preparation of the over denture abutments

Over-dentures on implantsOver-dentures on implants

Over dentures supported by implants are comparatively newOver dentures supported by implants are comparatively newarrivals on the prosthodontic scene.arrivals on the prosthodontic scene.

Compared with an implant supported fixed partial denture anCompared with an implant supported fixed partial denture animplant supported over-denture requiresimplant supported over-denture requires

Less supportLess support Offers more flexibilityOffers more flexibility

Seldom causes speech difficultiesSeldom causes speech difficulties And is more economical And is more economical On the other hand, many workers have reported complicationsOn the other hand, many workers have reported complications

with maintenance therapy. It has become apparent that implantswith maintenance therapy. It has become apparent that implantsare particularly susceptible to overload, and especially to forcesare particularly susceptible to overload, and especially to forcesthat are non axial.that are non axial.

Construction of an over-denture supported byConstruction of an over-denture supported by bothboth roots androots andimplant is normally ill-advisedimplant is normally ill-advised



CLASSIFICATION CLASSIFICATION

Broadly classified intoBroadly classified into

Tooth-supported dentureTooth-supported denture

Implant Supported Over DentureImplant Supported Over Denture



Heartwel’s classification of tooth supportedHeartwel’s classification of tooth supported

denturedenture

Based on the method of abutmentBased on the method of abutmentpreparation.preparation.

Simple tooth modification andSimple tooth modification andreductionreduction

Tooth reduction and copingTooth reduction and coping Endodontic treatment and amalgamEndodontic treatment and amalgam

plug / compositeplug / composite

Endodontic treatment and copingEndodontic treatment and coping

Endodontic therapy with cast copingEndodontic therapy with cast coping

utilizing some form of Attachmentsutilizing some form of Attachments Submerged vital roots.Submerged vital roots.

Coping AttachmentsCoping Attachments



Simple tooth modification and reductionSimple tooth modification and reduction In this procedure remaining teeth are merely reshaped toIn this procedure remaining teeth are merely reshaped to

eliminate undercuts & reduced in vertical height to createeliminate undercuts & reduced in vertical height to create

more interoccusal spacemore interoccusal space The results of this technique in patients with microdontiaThe results of this technique in patients with microdontia

or partial anodontia are strikingor partial anodontia are striking

Endodontic treatment and amalgam plug/ compositeEndodontic treatment and amalgam plug/ composite

Widely usedWidely used Indicated when there is normal coronal height to the teethIndicated when there is normal coronal height to the teeth

& normal interocclusal distance with little or no vertical& normal interocclusal distance with little or no verticaldimension lossdimension loss

In cases to create space without opening of verticalIn cases to create space without opening of verticaldimension, endodontic procedure performed, toothdimension, endodontic procedure performed, toothsectioned at the gingival margin or slightly above above itsectioned at the gingival margin or slightly above above it( 1-2 mm) & the remaining dentin smoothened & polished( 1-2 mm) & the remaining dentin smoothened & polishedthoroughly with amalgam/ compositethoroughly with amalgam/ composite



Abutment with cast coping : Cast metal coping with a dome shaped Abutment with cast coping : Cast metal coping with a dome shapedsurface and chamfer finish line at the gingival margin aresurface and chamfer finish line at the gingival margin are

fabricated and cemented. There are 2 distinct types of copings :fabricated and cemented. There are 2 distinct types of copings : 1. The short coping, 2. The long coping1. The short coping, 2. The long coping The short coping : These are 2 to 3mm long and normally requireThe short coping : These are 2 to 3mm long and normally require

endodontic therapy since the required coronal tooth reductionendodontic therapy since the required coronal tooth reductionwould expose the pulp. Attached to the coping is a post, fitted towould expose the pulp. Attached to the coping is a post, fitted to

the canals. For this reason canals should be obturated with softthe canals. For this reason canals should be obturated with softGutta-Percha rather than metal points.Gutta-Percha rather than metal points. Long coping : These are normally 5 to 8mm long. An attempt isLong coping : These are normally 5 to 8mm long. An attempt is

made to circumvent endodontic therapy by a conservativemade to circumvent endodontic therapy by a conservativereduction with a cellsopidal shaped coronal coping and anreduction with a cellsopidal shaped coronal coping and an

increased crown root ratio which require greater level of osseousincreased crown root ratio which require greater level of osseoussupport. Adequate inter occlusal distance must exist to allow for support. Adequate inter occlusal distance must exist to allow for encroaching on the available inter ridge space or a visualizationencroaching on the available inter ridge space or a visualizationof vertical dimension is liable to occur with poor esthetics andof vertical dimension is liable to occur with poor esthetics andfailure because of patient intolerancefailure because of patient intolerance



Abutments with Attachments: Abutments with Attachments: Most attachments are secured to the abutment by a cast coping. TheMost attachments are secured to the abutment by a cast coping. The

objective of any attachment is to improve retention of the denture base.objective of any attachment is to improve retention of the denture base.Because of the factors like time, cost and risks the procedure shouldBecause of the factors like time, cost and risks the procedure shouldreserved for patient with a favourable prognosis. The attachment does notreserved for patient with a favourable prognosis. The attachment does notreduce the crown root ratio significantly as does the cast coping. Here thereduce the crown root ratio significantly as does the cast coping. Here thelow caries index proper home care. Periodontal health and inter ridgelow caries index proper home care. Periodontal health and inter ridgedistance are absolutely necessary.distance are absolutely necessary.

Submerged vital roots : This is of current research interest, it attempts toSubmerged vital roots : This is of current research interest, it attempts toobviate some basic problem associated with the more conventional over obviate some basic problem associated with the more conventional over

denture abutments. In these cases selected vital roots are transected anddenture abutments. In these cases selected vital roots are transected andreduced to 2mm below the crestal bone and then covered byreduced to 2mm below the crestal bone and then covered bymucoperiosteal flap.mucoperiosteal flap.

The major problem associated are development of dehiscences and pulpalThe major problem associated are development of dehiscences and pulpalpathosis. When this is done several advantages of the over denture arepathosis. When this is done several advantages of the over denture arelost.lost.

Support from direct contact of the denture base to the abutment tooth.Support from direct contact of the denture base to the abutment tooth. Attempts to gain retention fom the teeth through some form of attachment is Attempts to gain retention fom the teeth through some form of attachment is

no longer possible.no longer possible. The loss of proprioception.The loss of proprioception.



Location and distribution of abutment :Location and distribution of abutment : Preference for anterior over posterior teeth therefore the alveolar Preference for anterior over posterior teeth therefore the alveolar

ridge appears to be more vulnerable to reduction than theridge appears to be more vulnerable to reduction than the

posterior alveolar ridge.posterior alveolar ridge. Two teeth in each quadrant presents an ideal situation in whichTwo teeth in each quadrant presents an ideal situation in whichstress is distributed, over a rectangular area. Eg : Cuspid 2ndstress is distributed, over a rectangular area. Eg : Cuspid 2ndpremolar and/or 2nd molar in each quadrant.premolar and/or 2nd molar in each quadrant.

The tripod is the next most favourable form for support andThe tripod is the next most favourable form for support and

stability.stability. The use of two teeth in each arch or one tooth in one arch hasThe use of two teeth in each arch or one tooth in one arch hasmet with satisfactory results.met with satisfactory results.

Marrow recommends that it is better to use isolated teeth asMarrow recommends that it is better to use isolated teeth asabutments rather than adjacent teeth because they return to aabutments rather than adjacent teeth because they return to a

state of good health more readily and are easier for the patinet tostate of good health more readily and are easier for the patinet tomaintain hygiene.maintain hygiene. The upper anterior teeth should be retained if opposed by naturalThe upper anterior teeth should be retained if opposed by natural

lower anterior teeth to prevent the destruction of the anterior lower anterior teeth to prevent the destruction of the anterior ridge when utilized in a maxillary over denture.ridge when utilized in a maxillary over denture.

Mandibular cuspids are most often utilized since they are usuallyMandibular cuspids are most often utilized since they are usuallythe last tooth to be lostthe last tooth to be lost



Over Denture AttachmentsOver Denture Attachments

An An attachmentattachment is a mechanical device for the fixation, retention andis a mechanical device for the fixation, retention andstabilization of a dental prosthesesstabilization of a dental prostheses

Attachments Classification. Attachments Classification. According to shape, design and primary area of use. According to shape, design and primary area of use.

CoronalCoronal :: Intra coronalIntra coronal

Extra coronalExtra coronal-Resilient.-Resilient.

-Non resilient-Non resilient

Radicular Radicular :: Telescope stud attachmentsTelescope stud attachments Bar attachmentsBar attachments

-Bar Joints-Bar Joints

-Bar Units-Bar Units



Accessory : Auxiliary attachments Accessory : Auxiliary attachments Screw units.Screw units. Pawl connectors.Pawl connectors. Bolts.Bolts. Stabilizers / balancers.Stabilizers / balancers. InterlocksInterlocks

Pins/screws.Pins/screws. Rests.Rests.

MagnetsMagnets :: Permanent magent.Permanent magent.

Induced magnet.Induced magnet. Open field.Open field. Closed fieldClosed field

Extra CoronalExtra Coronal IntraIntra



Extra CoronalExtra Coronal IntraIntra Gerber attachmentsGerber attachments Zest Anchor Zest Anchor

Dalbo attachmentDalbo attachment

Ceka attachmentCeka attachment Rothermann attachmentRothermann attachment

Infrofix attachmentInfrofix attachment

Schubiger attachmentSchubiger attachment

Quinlican attachmentQuinlican attachment

The compact unit (Priska)The compact unit (Priska)

Battesti unitsBattesti units

Conod unitConod unit

Baer and Fah unitsBaer and Fah units

Kurer stud attachmentKurer stud attachment



A mounted diagnostic casts is an important aid to check A mounted diagnostic casts is an important aid to checkthe space available before an attachment is selected.the space available before an attachment is selected.

Most of the stud types can be considered to be snapMost of the stud types can be considered to be snapfasteners.fasteners.

Stud devices are simplest among all attachments.Stud devices are simplest among all attachments. The male part of the unit consists of a stud shapedThe male part of the unit consists of a stud shaped

projection soldered to the diaphragm of a dowel retainedprojection soldered to the diaphragm of a dowel retainedrestoration.restoration. The female part fits over the male unit and is embeddedThe female part fits over the male unit and is embedded

within the denture base of the prosthesis.within the denture base of the prosthesis.



There are a few systems which work in the reverse. eg.There are a few systems which work in the reverse. eg.Zest Anchor. A few studs are anteriorly rigid (because theZest Anchor. A few studs are anteriorly rigid (because thesize makes it difficult to prevent a small amount of size makes it difficult to prevent a small amount of movement between the two components). In somemovement between the two components). In somesprings are specifically incorporated to allow a controlledsprings are specifically incorporated to allow a controlled

degree of movement.degree of movement. Advantages : Advantages :

Retention, stability and support.Retention, stability and support. A positive lock of certain units can maintain the border A positive lock of certain units can maintain the border

seal of the dentureseal of the denture



Selection of attachments :Selection of attachments :

The success of prosthesis usually depends on careful treatmentThe success of prosthesis usually depends on careful treatmentplanning and attention to the prosthodontic problems. Theplanning and attention to the prosthodontic problems. The

mechanical ingenuity of the attachment is important, but mustmechanical ingenuity of the attachment is important, but musttake second place. The shape and size of the units is normallytake second place. The shape and size of the units is normallythe over riding consideration although the auxiliary devices thatthe over riding consideration although the auxiliary devices thataccompany the attachment must influence the choice.accompany the attachment must influence the choice.

Correct vertical space assessment must be taken care of. ExtraCorrect vertical space assessment must be taken care of. Extraradicular stud attachments are relatively strong and can oftenradicular stud attachments are relatively strong and can oftenprovide more effective retention than their interradicular counter provide more effective retention than their interradicular counter parts. Larger attachments are generally stronger than smaller parts. Larger attachments are generally stronger than smaller ones and less prone to wear. Debate still continues as to whether ones and less prone to wear. Debate still continues as to whether

or not the comparatively rigid units should be selected asor not the comparatively rigid units should be selected asopposed to those that allow movement.opposed to those that allow movement.

Mensor (1980) auotiny work by Fenner, Herber and MabiemannMensor (1980) auotiny work by Fenner, Herber and Mabiemann(1950) has claimed rigid or cylindrical stud attachments produce(1950) has claimed rigid or cylindrical stud attachments produceno tipping action on the root. Ball and socket designs are statedno tipping action on the root. Ball and socket designs are stated

to produce 4 times as much tipping potentialto produce 4 times as much tipping potential



A recent lab study by Thayer and Caputo (1980) employedA recent lab study by Thayer and Caputo (1980) employedphoto-elastic stress analysis. They found that forcesphoto-elastic stress analysis. They found that forcesapplied to a Dolder bar were resolved in an apicalapplied to a Dolder bar were resolved in an apicaldirection where as stud attachments engaging the doweldirection where as stud attachments engaging the dowelretained diaphragm might produce tipping potentials.retained diaphragm might produce tipping potentials.

Leverage effect upon the root has also an effect onLeverage effect upon the root has also an effect onattachment selection. Mouth preparation, ease of rebasingattachment selection. Mouth preparation, ease of rebasingand repair procedures also determine the type of studand repair procedures also determine the type of stud

attachment.attachment. The number of stud attachment :The number of stud attachment : One stud attachment on each side of the arch will usuallyOne stud attachment on each side of the arch will usually

suffice other remaining roots can be covered with simplesuffice other remaining roots can be covered with simplecopings. Increased number of attachments in a denturecopings. Increased number of attachments in a denture

does not produce a corresponding improvement indoes not produce a corresponding improvement inretention.retention.



POPULAR ATTACHMENT SYSTEMPOPULAR ATTACHMENT SYSTEM

Dalbo Stud UnitDalbo Stud Unit Ball and SocketBall and Socket

Rigid DalboRigid Dalbo Extremely popular of the designExtremely popular of the designseries, strength, time testedseries, strength, time tested

Features : 4mm high withFeatures : 4mm high withspherical shape male section,spherical shape male section,

easy to clean. The fingers of theeasy to clean. The fingers of thesocket are surrounded by nylonsocket are surrounded by nylonrings that simplifies adjustmentsrings that simplifies adjustments

Adjustments are simple to carryAdjustments are simple to carryout. Retention can be increasedout. Retention can be increasedby altering free ends of lamellaeby altering free ends of lamellae

Adjuncts :Adjuncts :

Adjusting tools : TighteningAdjusting tools : Tighteningdevice. Complimentary tool.device. Complimentary tool.Device to replace nylon sleeve.Device to replace nylon sleeve.Relocating dowel for rebasingRelocating dowel for rebasingimpressionimpression



The compact unit :The compact unit :

Height – 2.85 mmHeight – 2.85 mm

Diameter of retention knob is 2.9mmDiameter of retention knob is 2.9mm

Divergence of 10°between the alignment of 2Divergence of 10°between the alignment of 2attachment may be permitted without causingattachment may be permitted without causing

increased wear of male section. It was developedincreased wear of male section. It was developed

from the ancrofixfrom the ancrofix

Gerber AttachmentsGerber Attachments ::



Resilient that allows vertical movementResilient that allows vertical movement

Rigid attachment (popular).Rigid attachment (popular). Retention of both types of Gerber Retention of both types of Gerber

attachment is obtained by aattachment is obtained by aretaining spring in the female unitretaining spring in the female unitengaging a peripheral groove in theengaging a peripheral groove in themale section. The spring clip may bemale section. The spring clip may beremoved for adjustment byremoved for adjustment byunscrewing. The base of the femaleunscrewing. The base of the female

unit using the special instrumentunit using the special instrumentprovidedprovided

Both types of male unit screwed onBoth types of male unit screwed onto their soldering base andto their soldering base andprevented from unscrewing with aprevented from unscrewing with a

little resin cement. They may belittle resin cement. They may beunscrewed in the mouth with aunscrewed in the mouth with aheated screw driver. Leavingheated screw driver. Leavingexposed a screw thread projectingexposed a screw thread projectingfrom the base of the attachmentfrom the base of the attachment



Gerber pointed out that if two or more teeth wereGerber pointed out that if two or more teeth were

used, the most distal attachment should allow moreused, the most distal attachment should allow more

vertical play than the anterior ones, as it is likely thatvertical play than the anterior ones, as it is likely that

greater displacing force would be applied to the molar greater displacing force would be applied to the molar

surfaces of the prosthesissurfaces of the prosthesis



Ceka SystemCeka System

Two typesTwo types RigidRigid

Resilient.Resilient. Rigid and Resilient designs share aRigid and Resilient designs share a

common base.common base. But the Ceka extracoronal units areBut the Ceka extracoronal units are

not identical.not identical.

Therefore it is not possible toTherefore it is not possible tochange resilient for rigidchange resilient for rigidconstructions merely by changing,constructions merely by changing,the retention portions.the retention portions.

The vertical travel allowed by theThe vertical travel allowed by the

resilient stud unit is 0.4mm. theresilient stud unit is 0.4mm. theretention pin or male section isretention pin or male section isscrewed on to the base ring & has ascrewed on to the base ring & has arounded shape wider at top & splitrounded shape wider at top & splitvertically into 4 sections which arevertically into 4 sections which areflexible & capable of beingflexible & capable of beingcompressedcompressed



Anciliary instruments :Anciliary instruments :

•Locating deviceLocating device•Adjustments deviceAdjustments device•Changing attachmentsChanging attachments•Repair and rebasing deviceRepair and rebasing device

•Limiting factor is the verticalLimiting factor is the verticalspace required by the unitspace required by the unit

resulting in 5mm verticalresulting in 5mm vertical

space requirement for thespace requirement for the

attachment componentsattachment components

A ith ll tt h t tA ith ll tt h t t



As with all attachments systems As with all attachments systemstheir alignment with each other their alignment with each other and the path of insertion of theand the path of insertion of theprosthesis must be planned.prosthesis must be planned.

The attachment base is solderedThe attachment base is solderedto the prepared flat surface of to the prepared flat surface of the coping. The spring pin or the coping. The spring pin or male section may be removedmale section may be removedfrom its base, so this allowsfrom its base, so this allows

considerable versatility, sinceconsiderable versatility, sincebreakage of the pin is easilybreakage of the pin is easilysolved by removing it andsolved by removing it andreplacing it with another unit.replacing it with another unit.

This is done by a special toolThis is done by a special toolprovided with which the springprovided with which the spring

pin is unscrewed. While thepin is unscrewed. While theother end of the special tool mayother end of the special tool maybe used to increase the retentionbe used to increase the retentionby means of the wedge shapeby means of the wedge shapeinstrumentinstrument

CekaCeka

special toolspecial tool



IntrofixIntrofix is a solid tall cylinder is a solid tall cylinder

attachment that can be usedattachment that can be used

for fixed removable bridgefor fixed removable bridge

work as well as for work as well as for

overdenturesoverdenturesIt consists of 3 partsIt consists of 3 parts

A solder bar A solder bar

A replaceable and adjustable A replaceable and adjustable

male friction partmale friction part

A female cylindrical housing A female cylindrical housing

IntrofixIntrofix



Advantages Advantages DisadvantagesDisadvantages

Simple to useSimple to use Components areComponents are

replaceable andreplaceable andinterchangeable with theinterchangeable with thesolder base of the ancrofixsolder base of the ancrofix

(resilient type)(resilient type)

The attachment providesThe attachment providesgood seating and retentiongood seating and retention

Can be used inCan be used in

combination with resilientcombination with resilientattachmentsattachments

Service life is indefiniteService life is indefinite

Paralleling necessaryParalleling necessary Processed in theProcessed in the

laboratorylaboratory

Torque potential isTorque potential is

maximum if denturesmaximum if denturesbase is not adaptedbase is not adaptedproperlyproperly

IntrofixIntrofix



Schubiger Schubiger Consists of a short screwConsists of a short screw

(3mm in diameter) block for (3mm in diameter) block for bar fixation a larger (3.2mm)bar fixation a larger (3.2mm)one for fixed removableone for fixed removablebridge work and an individualbridge work and an individualcap core system.cap core system.

Over denture attachmentsOver denture attachmentshas 3 parts.has 3 parts.

Solder base common to theSolder base common to theGerber.Gerber.

A sleeve in ceramic metal. A sleeve in ceramic metal.

A cap nut. A cap nut. Overall height is 2.8mmOverall height is 2.8mm Bar is soldered to the sleeveBar is soldered to the sleeve



Schubiger Schubiger


Allows complete flexibility Allows complete flexibility

Provides for bar fixation.Provides for bar fixation.

Permits conversation fromPermits conversation frombar to individual studbar to individual studfixationfixation

BulkBulk

(Gerber) Paralleling is(Gerber) Paralleling isnecessarynecessary

Complex and expensive.Complex and expensive.



Rothermann UnitRothermann Unit Rigid (less height 1mm).Rigid (less height 1mm). Resilient (more height 1.7mm).Resilient (more height 1.7mm).

Advantages : Requires little verticalAdvantages : Requires little verticalspace and tolerance for limitedspace and tolerance for limitedmisalignment of attachments.misalignment of attachments.

It is a button shaped attachment with theIt is a button shaped attachment with themale unit incorporating a groove of male unit incorporating a groove of uneven depth.uneven depth.

The clip of the female section slides over The clip of the female section slides over the tapered upper edge of the male. Withthe tapered upper edge of the male. Withthe free ends of the female engaging thethe free ends of the female engaging thedeepest retaining groove.deepest retaining groove.

The female clip is designed to beThe female clip is designed to beretained with acrylic resin.retained with acrylic resin.

A modified version of the clip is nowA modified version of the clip is nowavailable with tagging that runs at rightavailable with tagging that runs at rightangles to the original design. Apart fromangles to the original design. Apart fromthe minimal vertical space requirementthe minimal vertical space requirementan additional advantageis the tolerancean additional advantageis the tolerancefor limited misalignment of attachmentfor limited misalignment of attachment

RIGID

RESILIENT

RIGID IN PLACE



O – ring system / Ball attachmentO – ring system / Ball attachment

O – ring are doughnut shaped,O – ring are doughnut shaped,

synthetic polymer that posses thesynthetic polymer that posses theability to bend with resistance & thenability to bend with resistance & then

return to their approximate positionreturn to their approximate position

The O ring attaches to post with aThe O ring attaches to post with a

groove or undercut area called thegroove or undercut area called the

internal cavity of the metal or plasticinternal cavity of the metal or plastic

encapsulator, which permits easyencapsulator, which permits easy

replacement of ring after wearing or replacement of ring after wearing or

damage for the ringdamage for the ring

The O ring requires 5-7mm height, theThe O ring requires 5-7mm height, the

greatest of any attachmentsgreatest of any attachments

O ring post usually made of machinedO ring post usually made of machinedtitanium alloy or cast in precioustitanium alloy or cast in precious

metalmetal

Post has a head. Body & neck. ThePost has a head. Body & neck. The

body of post is connected to thebody of post is connected to the

implant abutment or superstructureimplant abutment or superstructure

bar bar



O – ring systemO – ring system

ADVANTAGEADVANTAGE

Ease in changing the attachmentEase in changing the attachment

Wide range of movementWide range of movement

Low costLow cost

Different degree of retentionDifferent degree of retention Possible elimination of time & cost of a superstructure for thePossible elimination of time & cost of a superstructure for the

prosthesisprosthesis



INTRA RADICULAR STUD TTACHMENTSINTRA RADICULAR STUD TTACHMENTS The advantages of this system lies in costThe advantages of this system lies in cost

and space requirements. They do notand space requirements. They do notrequire precious metal coping dowel nor require precious metal coping dowel nor

special laboratory procedures. They arespecial laboratory procedures. They arerelatively simple and quick.relatively simple and quick.

Zest Anchor systemZest Anchor system :: It derives its retention from within the rootIt derives its retention from within the root A post preparation is made within the rootA post preparation is made within the root

& a female sleeve is cemented to place& a female sleeve is cemented to place

A male element that is nylon post & a ballA male element that is nylon post & a ballhead that is incorporated in the denturehead that is incorporated in the denturebase and projects downwards, engaging abase and projects downwards, engaging arecess in the root preparation, further therecess in the root preparation, further theloads are applied at a point. That is wellloads are applied at a point. That is wellapical to the gingival margin of the root.apical to the gingival margin of the root.

A variety of abutments may be employedA variety of abutments may be employedincluding hemisected molar roots. 2 sizesincluding hemisected molar roots. 2 sizesof zest anchor are available depending onof zest anchor are available depending onthe root length and diameter.the root length and diameter.

The systems has been extensively refinedThe systems has been extensively refinedover the years and a comprehensive kit isover the years and a comprehensive kit is

now availablenow available



The vertical space requirements are theThe vertical space requirements are thesame as Rothermann unitsame as Rothermann unit

ADVANTAGES ADVANTAGES

Attachment is within the root structure, Attachment is within the root structure,thus It overcomes any space problemthus It overcomes any space problem

Leverage on the abutment tooth isLeverage on the abutment tooth is

negligible as point of attachment is wellnegligible as point of attachment is wellbelow alveolar bone levelbelow alveolar bone level

Simple & attachment procedure can beSimple & attachment procedure can beperformed quickly at chair sideperformed quickly at chair side

If more than one toot is used parallelismIf more than one toot is used parallelismis not necessary because of theis not necessary because of theflexibility of the nylon maleflexibility of the nylon male

Zest system, showingnylon male

component projecting

from the denture &

female component

cemented into the root



DISADVANTAGESDISADVANTAGES Since no casting or coping usually made,Since no casting or coping usually made,

the root or canal itself susceptibile tothe root or canal itself susceptibile tocariescaries

The nylon studs may bent or even fracture,The nylon studs may bent or even fracture,preventing seating of the appliance,preventing seating of the appliance,especially if several are being used thusespecially if several are being used thusrequire frequent recall vistsrequire frequent recall vists

Vertical fracture of the rootVertical fracture of the rootINDICATIONINDICATION

Ideal for use in an interim overdentureIdeal for use in an interim overdenture



Bar compared to Stud FixationBar compared to Stud Fixation ::

Splinting of two or more teeth with a bar producesSplinting of two or more teeth with a bar producesstability similar to the rigid stud type attachment whenstability similar to the rigid stud type attachment whenthe overdenture is in place. But the study type allowthe overdenture is in place. But the study type allowindependent movement.independent movement.

If one tooth is weak the strong tooth can serve as theIf one tooth is weak the strong tooth can serve as the

fulcrum point for movement of the weaker tooth in thefulcrum point for movement of the weaker tooth in theprosthesis. With bar fixation, a stronger and a weaker prosthesis. With bar fixation, a stronger and a weaker tooth can be splinted with the result that the stronger tooth can be splinted with the result that the stronger tooth strengthens the weaker tooth and the weaker toothtooth strengthens the weaker tooth and the weaker toothweakens the stronger toothweakens the stronger tooth



Bar AttachmentsBar Attachments

The bar attachments help in splinting of the abutmentThe bar attachments help in splinting of the abutmentteeth, retention and support of the appliance. Theteeth, retention and support of the appliance. Theinter occlusal space availability has already beeninter occlusal space availability has already beenemphasized.emphasized.

Bar attachments are classified into two types bar Bar attachments are classified into two types bar

units and bar joints.units and bar joints. Bar unit has a rigid fixation where there is noBar unit has a rigid fixation where there is no

movement between the bar and overlying sleeve andmovement between the bar and overlying sleeve andcan be classified as tooth born.can be classified as tooth born.

Bar joints permits rotational movement betweenBar joints permits rotational movement between

sleeve and bar and derives more or residual ridgesleeve and bar and derives more or residual ridgesupport.support.



Types of Bar Attachments :Types of Bar Attachments :

Hader Bar.Hader Bar. Dolder bar attachment.Dolder bar attachment. Baker clips.Baker clips.

Ackerman clips andAckerman clips and C.M. clipC.M. clip

HADER BAR ATTACHMENTHADER BAR ATTACHMENT



HADER BAR ATTACHMENTHADER BAR ATTACHMENT Can serve as a bar joint or a bar unit.Can serve as a bar joint or a bar unit. Can be used as a stud attachment and aCan be used as a stud attachment and a

bar attachment.bar attachment. Consists of preformed plastic bars andConsists of preformed plastic bars andclipsclips

Helmet Hader developed the Hader bar &Helmet Hader developed the Hader bar &rider system in the late 1960’srider system in the late 1960’s

Its present form has been in use for Its present form has been in use for almost 30 yrsalmost 30 yrs English, Donnel & Staubli modified theEnglish, Donnel & Staubli modified the

system in 1992 to form the Hader EDSsystem in 1992 to form the Hader EDSsystemsystem

The EDS Hader system is only 3mm high,The EDS Hader system is only 3mm high,whereas the original was 8.3mm in heightwhereas the original was 8.3mm in height



The clips have 3 different retentionThe clips have 3 different retentionstrengths & a 20strengths & a 20 00 clip rotation whichclip rotation whichgreatly improves the flexibility of thegreatly improves the flexibility of the

system for a range of patient needs or system for a range of patient needs or desiredesire The clip rotation compensates for theThe clip rotation compensates for the

resilence of the tissue which is usuallyresilence of the tissue which is usually0.5 – 1 mm in the mandible0.5 – 1 mm in the mandible

The standard or EDS Hader bar has aThe standard or EDS Hader bar has around superior aspect & an apronround superior aspect & an aprontoward the tissue below which acts astoward the tissue below which acts asa stiffener to improve the strength of a stiffener to improve the strength of the bar & limit its flexibilitythe bar & limit its flexibility

Round bar designs flexes in relation toRound bar designs flexes in relation toXX44 i.e., bar twice as long flexesi.e., bar twice as long flexes2X2X2X2= 16 times more2X2X2X2= 16 times more



Fabrication :Fabrication :

The plastic bar is attached to the wax copingsThe plastic bar is attached to the wax copingsand is cast with the coping.and is cast with the coping.

Plastic clip is embedded in the denture for Plastic clip is embedded in the denture for retention.retention.

But metal clip offers more retention than theBut metal clip offers more retention than theplastic. Plastic clip wears off rapidly. For moreplastic. Plastic clip wears off rapidly. For more

retention additional clips can be added andretention additional clips can be added andtension of the metal clip can be increasedtension of the metal clip can be increased






Bars can be fabricated inBars can be fabricated inany alloy.any alloy.

Retention can be improvedRetention can be improvedby patient or dentist.by patient or dentist.

For more retention metalFor more retention metalclip can be used.clip can be used.

Assembly technique is Assembly technique issimple.simple.

Capability to followCapability to followgingival contours.gingival contours.

Rider is too bulkyRider is too bulkyocclusogingivally.occlusogingivally.

For additional retentionFor additional retentionmore metal clips should bemore metal clips should be

addedadded

Dolder Bar Dolder Bar



Has bar unit and bar jointHas bar unit and bar joint Preformed bars are available for Preformed bars are available for

bar units.bar units. Shape of the bar, has parallelShape of the bar, has parallel

sides with a rounded top.sides with a rounded top. Retention is by means of Retention is by means of

frictional fit.frictional fit. Non resilient attachment.Non resilient attachment. Fabrication :Fabrication :

The preformed bars areThe preformed bars aresoldered to the copings and thesoldered to the copings and thesleeve is embedded in thesleeve is embedded in theacrylic over denture.acrylic over denture.

Advantages :Advantages : Availability of two differentAvailability of two different

heights 1.465 mm and 3.6mm.heights 1.465 mm and 3.6mm. Rider and bar are available inRider and bar are available in

any lengths.any lengths. Spacer allows vertical andSpacer allows vertical and

rotational movement.rotational movement. Crossection through pear shaped

Dolber bar & retaining sleeve

incorporated into impression

surface of lower denture



Disadvantages :Disadvantages : Too bulky even inToo bulky even in

microsize (faciolingually).microsize (faciolingually). Expensive and requiresExpensive and requires

exceptional skill for itsexceptional skill for itsuse.use.

Allows vertical and Allows vertical androtational movementrotational movementbecause of the resilientbecause of the resilientattachment.attachment.

Contouring the bar joint isContouring the bar joint isdifficult.difficult.

Bulky and difficult to useBulky and difficult to usebecause of estheticbecause of estheticconsiderationsconsiderations



Baker ClipBaker Clip

Consists of ‘U’ shaped clip designed to fit over a round wire. 12Consists of ‘U’ shaped clip designed to fit over a round wire. 12and 14 roung gauge wire are used. These wires are soldered toand 14 roung gauge wire are used. These wires are soldered tothe copings. Clip is positioned over the wire and is attached tothe copings. Clip is positioned over the wire and is attached tothe over denture with cold cure resin.the over denture with cold cure resin.

Baker Clip :Baker Clip :

Advantages : Advantages :

Adjustable and provides rotational movement. Adjustable and provides rotational movement.

Readily available.Readily available.

Disadvantages :Disadvantages :

No retention for the clips.No retention for the clips.

Soldering the retentive loops reduces the elasticity of the clip.Soldering the retentive loops reduces the elasticity of the clip.

Ackerman and C.M. Clip Ackerman and C.M. Clip These are bar jointsThese are bar joints



These are bar joints.These are bar joints.

Both are similar in designs.Both are similar in designs.

Consists of a rounded bar and clip,Consists of a rounded bar and clip,where the clip fits over the bar.where the clip fits over the bar.

The slip has retention wings for theThe slip has retention wings for theeasy engagement into the acrylics.easy engagement into the acrylics.

Allows vertical and rotational Allows vertical and rotationalmovement because of fixation.movement because of fixation.

Provides an excellent retention for Provides an excellent retention for

overdenture when bar joint systemoverdenture when bar joint systemis used.is used.

Advantages : Advantages :

Rider is provided with retention.Rider is provided with retention.

Spaces provides resiliences andSpaces provides resiliences and

rotation (or) rotation alone if therotation (or) rotation alone if theshim is not used.shim is not used.


The basis can be only 1.9mm inThe basis can be only 1.9mm indiameter diameter

M i D R iM ti D t R t ti



Magnetic Denture RetentionMagnetic Denture Retention These have been in existanceThese have been in existance

since 1930.since 1930.

They can be divided into groups.They can be divided into groups.Those depending on the mutualThose depending on the mutual

repulsion of like magnetic poles.repulsion of like magnetic poles.e.g.. Friedman magnetice.g.. Friedman magneticstabilizers).stabilizers).

Disadvantages :Disadvantages : Less retentive when most neededLess retentive when most needed

(when jaws are part)(when jaws are part) Continued resorbtion.Continued resorbtion.

Those depending on the mutualThose depending on the mutual

attraction unlike poles.attraction unlike poles. Disadvantages : One continuousDisadvantages : One continuous

attracting forces could cause theattracting forces could cause theembedded bar magnets to moveembedded bar magnets to movethrough the bone, corrrode thethrough the bone, corrrode the

soft tissues and becomesoft tissues and become



In order to know about magnetic over denture the fieldIn order to know about magnetic over denture the field

strength and magnetic permanence are 2 terms which requirestrength and magnetic permanence are 2 terms which require

clear understanding. For dental use a high magnetic fieldclear understanding. For dental use a high magnetic fieldstrength is desirable as this will provide stronger retention.strength is desirable as this will provide stronger retention.

High permanence is essential for (1) it ensures magnet will beHigh permanence is essential for (1) it ensures magnet will be

less likely to lose its magnetism. (2) A small magnet can beless likely to lose its magnetism. (2) A small magnet can be

made without the north pole demagnetising the south pole.made without the north pole demagnetising the south pole.

Until 1970 magnets for dental purpose were either Alnico (Al,Until 1970 magnets for dental purpose were either Alnico (Al,

Co, Ni) or Co/Pt magnets both alloys have magnetic fieldCo, Ni) or Co/Pt magnets both alloys have magnetic field

strength. But their permanence is such that there is a lower strength. But their permanence is such that there is a lower

limit to their physical size and they cannot be made as smalllimit to their physical size and they cannot be made as small

as a tooth and have high field strength.as a tooth and have high field strength.



This limitation was eliminated by the discovery of the rareThis limitation was eliminated by the discovery of the rareearth cobalt (REC) magnet alloys. REC alloys have 5 toearth cobalt (REC) magnet alloys. REC alloys have 5 to40 times field strength. The common composition being40 times field strength. The common composition beingcobalt/samarium (CoSm). They were introduced tocobalt/samarium (CoSm). They were introduced toprosthodontics for retention by Gillings in 1977.prosthodontics for retention by Gillings in 1977.

In one approach magnets are attached to the supportingIn one approach magnets are attached to the supportingflush with the root faces. Similar but opposite polarityflush with the root faces. Similar but opposite polarityprovides retention in the range of 150-400 gms/magnetprovides retention in the range of 150-400 gms/magnetpair. Denture base/root face separation of as much aspair. Denture base/root face separation of as much as

3mm. There is no path of insertion restriction3mm. There is no path of insertion restriction




Small root surface of some supporting root limit theSmall root surface of some supporting root limit thesize of magnet that can be inserted and limit retention.size of magnet that can be inserted and limit retention.

The magnet alloy can corrode and fracture in theThe magnet alloy can corrode and fracture in themouth.mouth.

An avoidable magnetic field surrounds both the intra An avoidable magnetic field surrounds both the intraradicular and denture magnets.radicular and denture magnets.

These disadvantage was over come by replacement of These disadvantage was over come by replacement of one magnet with a magnetisable low intrinsic alloy,one magnet with a magnetisable low intrinsic alloy,without significant loss of retention. A casting alloywithout significant loss of retention. A casting alloybased on palladium, cobalt and nickle is cast as rootbased on palladium, cobalt and nickle is cast as root

cap and dowel and fitted to the supporting root. Thecap and dowel and fitted to the supporting root. Thecasting because of its magnetic coercivity becomes acasting because of its magnetic coercivity becomes astrong induced magnet and retains the denture like anstrong induced magnet and retains the denture like anintraradicular permanent magnet.intraradicular permanent magnet.



Biological Effects of Cobalt/Samarium Magnets :Biological Effects of Cobalt/Samarium Magnets : There are two ways in which Co/Sa magnets could have anThere are two ways in which Co/Sa magnets could have an

effect on tissues:effect on tissues:

Physical effect because of the presence of magnetic fieldPhysical effect because of the presence of magnetic fieldgradient.gradient.

Chemical effect due to wear or corrosion products of alloy.Chemical effect due to wear or corrosion products of alloy. Behrman (1960) in his study concluded that magnetic isBehrman (1960) in his study concluded that magnetic is

completely innocuous to tissues. Similar conclusions werecompletely innocuous to tissues. Similar conclusions werereached by Toto and Choukas.reached by Toto and Choukas. Tsutsui and his colleagues (1979) found alloy to be innocuous inTsutsui and his colleagues (1979) found alloy to be innocuous in

tissue culture test due to corrosion resistance. The wear rate of tissue culture test due to corrosion resistance. The wear rate of unprotected faces of magnets used for over denture retentionunprotected faces of magnets used for over denture retentionhas been found to be less than 1mm/sqmm/year. (Gillingshas been found to be less than 1mm/sqmm/year. (Gillings1978). This is several orders of magnitude less than the1978). This is several orders of magnitude less than therecommended maximum ingestion levels for cobalt andrecommended maximum ingestion levels for cobalt andsamariumsamarium



The external magnetic field can be virtually eliminated byThe external magnetic field can be virtually eliminated by

arranging paired magnets in a modified horse shoearranging paired magnets in a modified horse shoeconfiguration by which the retentive effect is almostconfiguration by which the retentive effect is almostdoubled.doubled.

The explanation of this apparently anomalous doublingThe explanation of this apparently anomalous doublingeffect is that in the open configurations the north andeffect is that in the open configurations the north and

south pole facing each other contribute to the retention,south pole facing each other contribute to the retention,but the remaining South and North poles do not and their but the remaining South and North poles do not and their potential retentive effect is thus wasted. Where as all thepotential retentive effect is thus wasted. Where as all theavailable magnetic field is used in no closed configuration.available magnetic field is used in no closed configuration.Both the open and closed field denture retention systemBoth the open and closed field denture retention systemare in current use.are in current use.



Comparison of magnetic retention and precision attachmentsComparison of magnetic retention and precision attachments

Simplicity.Simplicity.

Low cost.Low cost.

Self adjusting (Orthodontic tooth movement for passing contact).Self adjusting (Orthodontic tooth movement for passing contact).

Reusable.Reusable.

Inherent stress breaking.Inherent stress breaking.

Reseating after denture displacement.Reseating after denture displacement.

Freedom of lateral and rotational denture movement.Freedom of lateral and rotational denture movement.

Low potential for trauma to supporting roots.Low potential for trauma to supporting roots.

Ease of denture relining.Ease of denture relining. No special accessories are required.No special accessories are required.

Height of denture retention element is less than many precisionHeight of denture retention element is less than many precisionattachmentsattachments



SUBMERGED VITAL ROOTS : This is of current researchSUBMERGED VITAL ROOTS : This is of current researchinterest, it attempts to obviate some basic probleminterest, it attempts to obviate some basic problemassociated with the more conventional over dentureassociated with the more conventional over dentureabutments. In these cases selected vital roots areabutments. In these cases selected vital roots aretransected and reduced to 2mm below the crestal bonetransected and reduced to 2mm below the crestal boneand then covered by mucoperiosteal flap.and then covered by mucoperiosteal flap.

The major problem associated are development of The major problem associated are development of

dehiscences and pulpal pathosis.dehiscences and pulpal pathosis.When this is done several advantages of the over dentureWhen this is done several advantages of the over dentureare lost.are lost.

Support from direct contact of the denture base to theSupport from direct contact of the denture base to theabutment tooth.abutment tooth.

Attempts to gain retention form the teeth through some Attempts to gain retention form the teeth through someform of attachment is no longer possibleform of attachment is no longer possible

Clinical use of submerged vital roots as overdentureClinical use of submerged vital roots as overdentureabuments has yet not been successfulabuments has yet not been successful

Telescopic prosthesisTelescopic prosthesis



Telescopic prosthesisTelescopic prosthesis Minimum taper of copings is advised for best retention (lessMinimum taper of copings is advised for best retention (less

than 5 degrees of possible). Adequate height of the axial wallsthan 5 degrees of possible). Adequate height of the axial walls(at least 4mm)(at least 4mm)

Abutments for telescopic prosthesis will be covered by two Abutments for telescopic prosthesis will be covered by twolayers of metal while facial surfaces may require facings aslayers of metal while facial surfaces may require facings aswell.well.

The poorly executed abutment preparations result in thin inner The poorly executed abutment preparations result in thin inner coping that becomes perforated after a period of use also itcoping that becomes perforated after a period of use also itproduces a bulky and unsightly prosthesis.produces a bulky and unsightly prosthesis.

Occlusal reduction 2 – 3mm is minimum requirementOcclusal reduction 2 – 3mm is minimum requirement Marked reduction in restoration observed once the taper Marked reduction in restoration observed once the taper

increases beyond 6 degreesincreases beyond 6 degrees

Chamfer finish line is idealChamfer finish line is ideal Valuable in cleft palate patientValuable in cleft palate patient The removable section of the prosthesis requires equal care inThe removable section of the prosthesis requires equal care in

its planning as it is removable it requires sufficient strength toits planning as it is removable it requires sufficient strength towithstand handling by the patient.withstand handling by the patient.



Treatment planningTreatment planning ::

The sequence and technical procedures of preparatoryThe sequence and technical procedures of preparatory

treatment remains the same for all kinds of tooth supportedtreatment remains the same for all kinds of tooth supporteddenturesdentures

The only difference is in the design of the abutment teethThe only difference is in the design of the abutment teeth

The following sequence can be used as a general guide butThe following sequence can be used as a general guide butnot necessarily in all situationsnot necessarily in all situations

Construct an immediate Rx claspless denture & cast fromConstruct an immediate Rx claspless denture & cast fromirreversible hydrocolloid impressionirreversible hydrocolloid impression

Remove the hopeless teeth & insert the removable prosthesisRemove the hopeless teeth & insert the removable prosthesis

During healing period institute the periodontal and endodonticDuring healing period institute the periodontal and endodontic

treatmenttreatment



PREPARATION OF RETAINED TEETHPREPARATION OF RETAINED TEETH

►►Tooth preparation for minimal retentionTooth preparation for minimal retention

Sufficient tooth structure is removed to provide favorableSufficient tooth structure is removed to provide favorableroot crown ratio to allow the insertion of the artificialroot crown ratio to allow the insertion of the artificialprosthesis in an acceptable esthetic position & in aprosthesis in an acceptable esthetic position & in afavorable occlusal relation with the teeth of opposingfavorable occlusal relation with the teeth of opposingarcharch

Extend a chamfer type margin slightly beneath the freeExtend a chamfer type margin slightly beneath the free

gingival margingingival marginTaper the preparation in occlusogingival directionTaper the preparation in occlusogingival direction

The finished tooth with attached coping is the male member The finished tooth with attached coping is the male member of the denture & the female member is a part of theof the denture & the female member is a part of thedenture basedenture base

The occlusal or incising surface must be a dimensionThe occlusal or incising surface must be a dimensionsuitable to provide an area for placing of a concavity insuitable to provide an area for placing of a concavity inthe coping to accommodate CoCr bearing with radius of the coping to accommodate CoCr bearing with radius of the concavity slightly more than the radius of curvaturethe concavity slightly more than the radius of curvatureof the bearingof the bearing

►► Coping fabricationCoping fabrication



►► Coping fabricationCoping fabrication Make an accurate impression of the abutment andMake an accurate impression of the abutment and

pour a diepour a die

Carve the wax pattern and place the concavity inCarve the wax pattern and place the concavity inthe occlusal surfacethe occlusal surface Cast the coping, and cement the polished coping

to the tooth

►►Denture fabricationDenture fabricationPrimary ImpressionPrimary Impression makingFinal impression makingRecord bases and occlusal rims prepared - The only

difference is the incorporation of the metal bearing inthe record base. Apply one thickness of baseplatewax to the abutment leaving the occlusal surfaceexposed. Seat the bearing in the concavity & seal it inplace with wax. Construct the record base of activated acrylic resin using sprinkle on technique.Attach wax occlusal rims to the base



• Record maxillomandibular relation

• Trying in the teethLaboratory procedure

• Contour the wax• Flask the denture• Eliminate the wax

• At this step remove the metal bearings from theacrylic resin tooth cleaned with boiling water &dried

• The cast allowed to dry and abutment except theconcavity are painted with tin foil subsitute

• The metal bearing seated in concavity and acoping of activated acrylic resin with crosslinkedmonomer made, using the sprinkle on technique



• The procedure ensures the correct positioning of thebearing & allow trial packing of the heat cured acrylicresin denture base

• While the resin is in dough stage the coping withbearing is held securely in place & small amount of dough pressed around the gingival surface of the

coping and packing completed• After denture processed, remount procedure for

occlusal errors completed• Denture finished and polished



Clinical experience supports the recommendation of atClinical experience supports the recommendation of atleast one abutment/quadrant and the retained teethleast one abutment/quadrant and the retained teethshould be preferably not be the adjacent ones, or thereshould be preferably not be the adjacent ones, or thereshould be several millimeters of space between theshould be several millimeters of space between thereduced tooth forms.reduced tooth forms.

Mandibular canines are most often utilized because theyMandibular canines are most often utilized because theyare usually the last teeth to be lost. If only a single toothare usually the last teeth to be lost. If only a single tooth

remains this also should be retained as one tooth for remains this also should be retained as one tooth for support and bone preservation is better than none.support and bone preservation is better than none.

When Canines and premolars are present, it is better toWhen Canines and premolars are present, it is better tomaintain the canines and second premolars as this willmaintain the canines and second premolars as this willgive better support and also allows for more favorable oralgive better support and also allows for more favorable oral

hygiene.hygiene.

IMPLANT OVERDENTURE



Patients who benefit frommandibular Overdentures

Are usually elderly (65 to80+ years)

Are edentulous in themaxilla and mandible

Have worn completedentures for many years

Are uncomfortable with acomplete mandibular denture

Demand stabilization of denture

If not yet edentulous, theyexhibit extremely reducedresidual dentition that cannotbe maintained

Patients who benefit from maxi

Overdentures• Are in the younger segment Of

older patients (50 to 60 years)

• Have no experience with

maxillary removable prosthesis

• Exhibit hopeless residual

maxiliary dentition

• Are fearful of becoming

edentulous

• Have high esthetic demands• Have natural teeth or fixed

mandible

• Desire fixed reconstruction

INDICATIONS

Implant Overdenture Advantages



Minimum anterior bone loss; prevents bone loss Improved esthetics Improved stability (reduces or eliminates prosthesis movement)

Improved occlusion (reproducible centric relation occlusion) Decrease in soft tissue abrasions Improved chewing efficiency and force Increased occlusal efficiency

Improved retention Improved support Improved speech Reduced prosthesis size (eliminates palate flanges)

Improved maxillofacial prostheses

Implant Overdenture Advantages

Implant Overdenture Disadvantages



Implant Overdenture Disadvantages

Abutment crown height space required Abutment crown height space required

Long term maintainenceLong term maintainence

Food impactionFood impaction

Continued posterior bone lossContinued posterior bone loss

Guidelines for Mandibular Overdenture



Guidelines for Mandibular Overdenture

Fabrication

Two intraforaminal implants(approximately 4 mm in diameter and aminimum of 8 mm in length) arereccommended

The distance between the implantsshould be15 to 25 mm, depending on

the size & curvature of the anterior arch. The implant can be splinted with aclip-bar (resilient retention) or a U-shaped bar (rigid retention as well assingle anchors, such ball attachments.

Three or four implants are

recommended when implants of reduced length or diameter are used. Inthis case distance between the implantsshould be 12 – 15 mm to allow for areasonable length of the bar segments

Guidelines for Maxillaiy Overdenture



Fabrication

A minimum of four implants evenlydistributed over the anterior arch ispreferred.

Standard size and reduced-diameter implants can be used in the same arch.A splinting bar (preferably rigid) isrecommended, although ball anchorscan be used for temporary adaptation,

Retention with ball anchors may not beadequate in every situation due todivergent implant axes.

It is suggested that the denture base bereinforced with a cast metal framework;this increases the initial cost, but it

may reduce maintenance costs sincefractures and other complications canbe avoided

Special anatomic situations, such ascongenital defects, require individualfabrication of maxillary prostheses



CONCLUSIONCONCLUSION

Over dentures are both versatile andOver dentures are both versatile and

valuable method of treatment with ever valuable method of treatment with ever

increasing applications, but it is importantincreasing applications, but it is importantto visualize the final result at the treatmentto visualize the final result at the treatment

planning stage itself for ensuring aplanning stage itself for ensuring a

successful treatment.successful treatment.

Documents

Supradentalne proteze - indikacije, kontraindikacije, tretman