Precision attachments1 / dental implant courses by Indian dental academy

Precision AttachmentsPrecision Attachments
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.comwww.indiandentalacademy.com

ContentsContents
 IntroductionIntroduction
 HistoryHistory
 UsesUses
 GoalsGoals
 Mechanism of actionMechanism of action
 IndicationsIndications
 ContraindicationsContraindications
 AdvantagesAdvantages
 DisadvantagesDisadvantages
 ClassificationClassification

 Materials used in attachment fabricationMaterials used in attachment fabrication
 Treatment planningTreatment planning
 The free end saddleThe free end saddle
 The bounded saddleThe bounded saddle
 Over denturesOver dentures
 Auxiliary attachmentsAuxiliary attachments
 Milling using a precision parallelometerMilling using a precision parallelometer
 Use of precision attachments with implantsUse of precision attachments with implants
 ConclusionConclusion
 BibliographyBibliography

IntroductionIntroduction
 Precision attachments offer considerablePrecision attachments offer considerable
advantages in dentistry because of theiradvantages in dentistry because of their
flexibility.flexibility.
 Nevertheless they have in the past been largelyNevertheless they have in the past been largely
ignored by most dental professionals forignored by most dental professionals for
understandable reasons.understandable reasons.
 Precision attachments consist of two halves, aPrecision attachments consist of two halves, a
matrix and a patrix, that form a precise butmatrix and a patrix, that form a precise but
separable joint.separable joint.

 Precision attachments are defined as ;Precision attachments are defined as ;
A retainer used in fixed and removableA retainer used in fixed and removable
prosthesis construction consisting of a metalprosthesis construction consisting of a metal
receptacle and a closely fitting part. Thereceptacle and a closely fitting part. The
former is usually contained within the normalformer is usually contained within the normal
or expanded contours of the crown and theor expanded contours of the crown and the
later is attached to the pontic or denturelater is attached to the pontic or denture
framework.framework.

SynonymsSynonyms
 Internal attachmentsInternal attachments
 key and key-way attachmentskey and key-way attachments
 parallel attachmentsparallel attachments
 slotted attachmentslotted attachment
Male attachment female attachmentMale attachment female attachment
-patrix -matrix-patrix -matrix
-flange -slot-flange -slot
-insert, fitting part -receptacle-insert, fitting part -receptacle
-key -keyway, crypt-key -keyway, crypt

HistoryHistory
 Prior to 1888, both winder and parr invented devicesPrior to 1888, both winder and parr invented devices
which were clearly attachments in principles andwhich were clearly attachments in principles and
construction.construction.
 In 1906 Dr. Herman E.S. Chayes invented aIn 1906 Dr. Herman E.S. Chayes invented a
detachable suspender device which formed thedetachable suspender device which formed the
fundamental feature of his dental attachment.fundamental feature of his dental attachment.
 In 1912 he designed the Chayes attachment calledIn 1912 he designed the Chayes attachment called
bucco-lingual attachment which forms the basicbucco-lingual attachment which forms the basic
pattern for the modern frictional grip attachment.pattern for the modern frictional grip attachment.
 1951 Mc collum made the greatest progress in the1951 Mc collum made the greatest progress in the
development of precision attachment.development of precision attachment.

UsesUses
 They are used to overcome alignmentThey are used to overcome alignment
problems where abutments have differingproblems where abutments have differing
paths of withdrawal.paths of withdrawal.
 As connecters in fixed partial dentureAs connecters in fixed partial denture
construction.construction.
 To retain removable partial dentures.To retain removable partial dentures.
 To retain overdentures.To retain overdentures.

GoalsGoals
 To provide an efficient masticatoryTo provide an efficient masticatory
replacement of lost dental organs.replacement of lost dental organs.
 To relate the designed platform to theTo relate the designed platform to the
available tooth support.available tooth support.
 To allow normal anatomic forms to theTo allow normal anatomic forms to the
abutment teeth.abutment teeth.

 Should be removable and replaceable withoutShould be removable and replaceable without
stress and strain on the abutment teeth.stress and strain on the abutment teeth.
 Should be capable of being tissue supported inShould be capable of being tissue supported in
a controlled manner.a controlled manner.
 Should allow for various Occlusal patterns.Should allow for various Occlusal patterns.
 Should provide many years of comfortableShould provide many years of comfortable
service.service.

 To have minimum amount of tooth structureTo have minimum amount of tooth structure
removed.removed.
 To place minimum amount of strain onTo place minimum amount of strain on
abutment teeth.abutment teeth.
 To be esthetically acceptable.To be esthetically acceptable.

Mode of action of precisionMode of action of precision
attachmentsattachments
 FrictionFriction
 BindingBinding
 Wedging of conical bodiesWedging of conical bodies
 Internal spring loadingInternal spring loading
 Active retentionActive retention

Friction:Friction:
 It occurs when parallel walls ofIt occurs when parallel walls of
closely fitting bodies pass over oneclosely fitting bodies pass over one
another.another.
 The frictional force is directly relatedThe frictional force is directly related
to the area of the opposing surfacesto the area of the opposing surfaces
as well as to the length of axial walls.as well as to the length of axial walls.
 The shape of the passage also plays aThe shape of the passage also plays a
substantial role.substantial role.

 The holding ability of the frictionalThe holding ability of the frictional
attachments can be enhanced by addition ofattachments can be enhanced by addition of
active retention elements .active retention elements .
 They areThey are
spring loaded bolts or plungers.spring loaded bolts or plungers.
Ring springsRing springs
Leaf springsLeaf springs
BoltsBolts
Rubber devices.Rubber devices.

Binding:Binding:
 It occurs when a parallel walledIt occurs when a parallel walled
body tips with in the receptor site.body tips with in the receptor site.
 Eccentric loads or frictionalEccentric loads or frictional
elements produce tippingelements produce tipping
movement,which enhances transmovement,which enhances trans
additional binding effectadditional binding effect
significantly increases resistance tosignificantly increases resistance to
withdrawal.withdrawal.

Wedging of conical bodies:Wedging of conical bodies:
 Friction comes to play onlyFriction comes to play only
in the terminal position andin the terminal position and
is lost as soon as the bodiesis lost as soon as the bodies
began to separate.began to separate.

Internal spring loadingInternal spring loading
 This is produced by a clip with inThis is produced by a clip with in
a cylinder.a cylinder.
 The friction with in retainers isThe friction with in retainers is
often increased by loading withoften increased by loading with
internal spring clips.internal spring clips.
 Slots in the male portion allowsSlots in the male portion allows
the pressure to be adjusted.the pressure to be adjusted.

Active retention:Active retention:
 That is when one body must beThat is when one body must be
temporarily deformed to betemporarily deformed to be
withdrawn from its fully seatedwithdrawn from its fully seated
position.position.
 Active retention means a physicalActive retention means a physical
obstruction to separation of otherobstruction to separation of other
parts.parts.
 One part must undergo elasticOne part must undergo elastic
deformation before separation candeformation before separation can
occur.occur.

IndicationsIndications
Depending on what the attachment is designedDepending on what the attachment is designed
to accomplish.to accomplish.
 Primary indication is for clasp eliminationPrimary indication is for clasp elimination
when esthetics is of prime importance.when esthetics is of prime importance.
 For patients with reduced periodontal support.For patients with reduced periodontal support.
 In patients where cross arch stabilization isIn patients where cross arch stabilization is
desired.desired.

 The attachment is indicated in combination withThe attachment is indicated in combination with
fixed and removable prostheses.fixed and removable prostheses.
 The attachment is indicated where removableThe attachment is indicated where removable
partial denture design require stress equalizationpartial denture design require stress equalization
which is of paramount importance.which is of paramount importance.
 Long span edentulous areas.Long span edentulous areas.
 To stabilize unilateral saddles.To stabilize unilateral saddles.

ContraindicationsContraindications
 Poor mental attitude of the patient is a definitePoor mental attitude of the patient is a definite
contraindication.contraindication.
 Poor oral hygiene.Poor oral hygiene.
 One of the primary contraindications for theseOne of the primary contraindications for these
prosthesis is space, whether it be vertical,prosthesis is space, whether it be vertical,
bucco-lingual, mesio-distal, circumferential, orbucco-lingual, mesio-distal, circumferential, or
interproximal.interproximal.
 In healthy mouths not requiring restoration forIn healthy mouths not requiring restoration for
other reasons.other reasons.

AdvantagesAdvantages
 The principal advantage of attachments forThe principal advantage of attachments for
removable partial denture is esthetics.removable partial denture is esthetics.
 Retention is an advantage for overdenturesRetention is an advantage for overdentures
abutments.abutments.
 Stress distribution.Stress distribution.
 Cross arch stabilization.Cross arch stabilization.

DisadvantagesDisadvantages
 The cost of the service is major factor.The cost of the service is major factor.
 Attachments are expensive.Attachments are expensive.
 Additional post-insertion care is required.Additional post-insertion care is required.
 Additional chair and laboratory time is needed.Additional chair and laboratory time is needed.
 Greater experience and knowledge on the partGreater experience and knowledge on the part
of the dentist and laboratory technician areof the dentist and laboratory technician are
essential.essential.
 Require repair and replacement.Require repair and replacement.

ClassificationClassification

Classified in number of ways:Classified in number of ways:
 Based on fabricationBased on fabrication
1.Semi precision1.Semi precision
2.Precision.2.Precision.
 Based on functionBased on function
1.Resilient1.Resilient
2. Non-resilient.2. Non-resilient.

By RayBy Ray
Active attachmentsActive attachments
e.g.: split patrix, crismani.e.g.: split patrix, crismani.
Passive attachmentsPassive attachments
e.g.: passive mega attachmentse.g.: passive mega attachments

By Collin. R. Corwell.By Collin. R. Corwell.
 Based on the shape and locationBased on the shape and location
1.coronal-Intracoronal ---frictional1.coronal-Intracoronal ---frictional
mechanicalmechanical
-Extra coronal eg:Dalbo hinge-Extra coronal eg:Dalbo hinge
- circumcoronal eg:Telescopic crown- circumcoronal eg:Telescopic crown
2.Radicular-eg:Rotherman2.Radicular-eg:Rotherman
3.Interdental-eg:Ackerman3.Interdental-eg:Ackerman
4.Auxiliary-eg:Ipsoclip4.Auxiliary-eg:Ipsoclip

 Based on location or placement [by preiskel]Based on location or placement [by preiskel]
1.Intracoronal1.Intracoronal
2.Extracoronal2.Extracoronal
3.Studs3.Studs
4.Bars4.Bars

According to Gareth JenkinsAccording to Gareth Jenkins
1.Extra Coronal1.Extra Coronal
2.Intra Coronal2.Intra Coronal
3.Auxiliary3.Auxiliary
4.Achors4.Achors
5.Bars5.Bars

Extra Coronal PrecisionExtra Coronal Precision
Attachments:Attachments:
 It can be Rigid orIt can be Rigid or
Resilient.Resilient.
 Distributes the potentialDistributes the potential
harmful forces awayharmful forces away
from the abutment to thefrom the abutment to the
edentulous ridges.edentulous ridges.
 This is useful with freeThis is useful with free
end saddles.end saddles.
 The Patrix is completelyThe Patrix is completely
outside the normaloutside the normal
contour of that retainer.contour of that retainer.
The Matrix is housedThe Matrix is housed
with in the prosthesis.with in the prosthesis.

Extra coronal Rigid Slide AttachmentsExtra coronal Rigid Slide Attachments::
Bi-Nat AttachmentsBi-Nat Attachments
 HeightHeight : 4mm.: 4mm.
 ApplicationApplication: Bilateral free: Bilateral free
end saddles,Removable andend saddles,Removable and
fixed partial dentures.fixed partial dentures.
 ActivationActivation:There is a:There is a
synthetic friction buffersynthetic friction buffer
housed in the patrix , turn thehoused in the patrix , turn the
locking screw to expand thelocking screw to expand the
synthetic friction buffer andsynthetic friction buffer and
increase the retention.increase the retention.

Extra coronal resilient attachmentExtra coronal resilient attachment::
Dalbo-s resilient joint:Dalbo-s resilient joint:
 HeightHeight : 5mm.: 5mm.
 ApplicationApplication: Bilateral: Bilateral
and unilateral free endand unilateral free end
saddles,long denturesaddles,long denture
saddles.saddles.
 ActivationActivation:Bend:Bend
lamellae of the matrixlamellae of the matrix
towards the center withtowards the center with
an instrument.an instrument. www.indiandentalacademy.comwww.indiandentalacademy.com

PR Hinge Attachments:PR Hinge Attachments:
 HeightHeight : 4.5mm.: 4.5mm.
 ApplicationApplication: Bilateral: Bilateral
and unilateral free endand unilateral free end
saddles.saddles.
 ActivationActivation:To increase:To increase
retention ,screw in theretention ,screw in the
locking screw which islocking screw which is
housed in the matrix.housed in the matrix.

Intra Coronal Precision AttachmentIntra Coronal Precision Attachment
 Here the matrix is contained with in theHere the matrix is contained with in the
contour of the crown.contour of the crown.
 It is useful during the preparation to haveIt is useful during the preparation to have
either the attachment or plastic dummy to helpeither the attachment or plastic dummy to help
ensure that sufficient space is provided.ensure that sufficient space is provided.
 There are two groups of intra coronalThere are two groups of intra coronal
attachments, non adjustable and adjustable.attachments, non adjustable and adjustable.

Non adjustable intra coronal AttachmentsNon adjustable intra coronal Attachments::
Rod and tube attachmentsRod and tube attachments
 ApplicationApplication:Fixed partial:Fixed partial
dentures with a minor alignmentdentures with a minor alignment
problem of the abutments.problem of the abutments.
 Used as a connector for denturesUsed as a connector for dentures
and to support one end of theand to support one end of the
removable partial denture whichremovable partial denture which
is retained at the other end by anis retained at the other end by an
adjustable retentive attachment.adjustable retentive attachment.

Key and Keyway Laboratory madeKey and Keyway Laboratory made
attachment:attachment:
 ApplicationApplication: used to: used to
correct minor alignmentcorrect minor alignment
problems in fixed partialproblems in fixed partial
dentures and in fixeddentures and in fixed
and semi fixed denturesand semi fixed dentures
when minor and majorwhen minor and major
retainers are used.retainers are used.

Adjustable Intra Coronal AttachmentsAdjustable Intra Coronal Attachments::
Ancra AttachmentsAncra Attachments
 ApplicationApplication : Removable: Removable
fixed partial dentures,Crossfixed partial dentures,Cross
arch stabilization,partialarch stabilization,partial
dentures and minordentures and minor
alignment problems withalignment problems with
posterior abutment teeth.posterior abutment teeth.
 ActivationActivation: Expand the slot: Expand the slot
with a suitable instrument.with a suitable instrument.

AnchorsAnchors
 These attachments are used on either roots orThese attachments are used on either roots or
implants to retain overdentures or removableimplants to retain overdentures or removable
partial dentures.partial dentures.
 The patrix is soldered to the diaphragm of aThe patrix is soldered to the diaphragm of a
cast post and the matrix contained in thecast post and the matrix contained in the
denture.denture.
 There are two basic types-Rigid and Resilient.There are two basic types-Rigid and Resilient.
 Rigid attachments are used in boundedRigid attachments are used in bounded
unilateral or bilateral saddle cases.unilateral or bilateral saddle cases.
 Resilient attachments are used in bilateral freeResilient attachments are used in bilateral free
end saddle cases.end saddle cases.

Rigid Anchors:Rigid Anchors:
eccentric rothermann attachmenteccentric rothermann attachment
 Height: 1.1 mmHeight: 1.1 mm
 Application: to retainApplication: to retain
rigid hybrid dentures.rigid hybrid dentures.
 Activation: bend theActivation: bend the
clasp arms of the matrixclasp arms of the matrix
towards the centre.towards the centre.

Resilient AnchorsResilient Anchors
compact anchors:compact anchors:
 Height: 2.85mmHeight: 2.85mm
 Application: To retainApplication: To retain
over dentures.over dentures.
 Activation: bend theActivation: bend the
lamellae of the matrixlamellae of the matrix
towards the centre.towards the centre.

Bar AttachmentsBar Attachments
 The bar being in the patrix is attached to theThe bar being in the patrix is attached to the
retainers while the matrix sleeve or clips orretainers while the matrix sleeve or clips or
riders are processed into the dentures.riders are processed into the dentures.
 They are used to retain overdentures orThey are used to retain overdentures or
removable partial dentures.removable partial dentures.
 They can also be used in conjunction withThey can also be used in conjunction with
crowns and implants.crowns and implants.
 They are either commercially or laboratoryThey are either commercially or laboratory
manufactured.manufactured.
 Bars can be Resilient or Rigid.Bars can be Resilient or Rigid.www.indiandentalacademy.comwww.indiandentalacademy.com

Rigid BarsRigid Bars
Rigid Dolder bar:Rigid Dolder bar:
 Height: 3.5mmHeight: 3.5mm
 Application: partial,Application: partial,
hybrid and implanthybrid and implant
dentures.dentures.
 Activation: Bend bothActivation: Bend both
sides of the sleevesides of the sleeve
towards the centre withtowards the centre with
an activating tool.an activating tool.

Resilient bar:Resilient bar:
Ackermann Bar and Clip:Ackermann Bar and Clip:
 There are two types ofThere are two types of
Ackerman bar:Ackerman bar:
1] round1] round
2] egg shaped2] egg shaped
The round bar is most frequentlyThe round bar is most frequently
used as it can be bend moreused as it can be bend more
easily to follow the contour ofeasily to follow the contour of
the ridge and arch.the ridge and arch.

 Applications: Partial dentures,over denturesApplications: Partial dentures,over dentures
and implant dentures.and implant dentures.
 Activation: Bend both sides of the clip towardsActivation: Bend both sides of the clip towards
center with an instrument.center with an instrument.

Auxiliary AttachmentsAuxiliary Attachments
 This group of attachments covers a wide rangeThis group of attachments covers a wide range
of applications.of applications.
 They serve these situations ;They serve these situations ;
a.] Allows planning which will enable thea.] Allows planning which will enable the
clinician to remove the prostheses for repair orclinician to remove the prostheses for repair or
conversion.conversion.
b.] Overcome alignment problems which ariseb.] Overcome alignment problems which arise
when abutments converge, making itwhen abutments converge, making it
impossible to prepare them so that they can beimpossible to prepare them so that they can be
mutually withdrawn when constructing fixedmutually withdrawn when constructing fixed

c.] Replace the loss of soft tissue in anteriorc.] Replace the loss of soft tissue in anterior
fixed partial dentures. Supplements retentionfixed partial dentures. Supplements retention
on bars and telescopic crowns.on bars and telescopic crowns.

Presso -Matic:Presso -Matic:
 ApplicationApplication: To supplement: To supplement
the retention on milledthe retention on milled
laboratory- made bars andlaboratory- made bars and
telescopic crowns used totelescopic crowns used to
retain removable partialretain removable partial
dentures and over dentures.dentures and over dentures.
 ActivationActivation:Replace the plastic:Replace the plastic
cushion and plunger.cushion and plunger.

Screw and Tube Attachments:Screw and Tube Attachments:
 ApplicationsApplications : To overcome: To overcome
minor and major withdrawalminor and major withdrawal
problems where abutmentsproblems where abutments
cannot be paralleled and tocannot be paralleled and to
provide contingency planningprovide contingency planning
for long span fixed partialfor long span fixed partial
dentures and full archdentures and full arch
restorations when used inrestorations when used in
conjunction with inner thimbleconjunction with inner thimble
crowns.crowns.

Materials used in attachmentMaterials used in attachment
fabricationfabrication
 PlatinumPlatinum
 IridoplatinumIridoplatinum
 Gold and platinumGold and platinum
 Gold and palladiumGold and palladium

Treatment planningTreatment planning
 Essential information which must be obtainedEssential information which must be obtained
for an adequate treatment plan includes:for an adequate treatment plan includes:
 Medical and dental historyMedical and dental history
 Discussion of patient expectationsDiscussion of patient expectations
 Extra oral examination.Extra oral examination.

 Intraoral examinationIntraoral examination
 Periodontal surveyPeriodontal survey
 Occlusal analysisOcclusal analysis
 RadiographsRadiographs
 Study modelsStudy models

Medical and dental historyMedical and dental history
 It is important to know significant previousIt is important to know significant previous
history.history.
 If the patient has already undertakenIf the patient has already undertaken
restorative work of a complex nature that hasrestorative work of a complex nature that has
failed, then the reasons for such failure mustfailed, then the reasons for such failure must
be examined.be examined.
 The ability of the patient to withstand longThe ability of the patient to withstand long
clinical procedures should be assessed at thisclinical procedures should be assessed at this
early stage.early stage.

Discussion of patient expectationsDiscussion of patient expectations
 Patient should be encouraged to comment onPatient should be encouraged to comment on
the appearance of their existing teeth, and tothe appearance of their existing teeth, and to
discuss their desires for the new ones.discuss their desires for the new ones.
 These are always the most difficult to satisfyThese are always the most difficult to satisfy
and careful counselling may be necessary toand careful counselling may be necessary to
achieve an acceptable compromise.achieve an acceptable compromise.

Extra oral examinationExtra oral examination
 An appraisal can be made almost before theAn appraisal can be made almost before the
patient is seated in the dental chair.patient is seated in the dental chair.
 Any asymmetry should be noted.Any asymmetry should be noted.

Intraoral examinationIntraoral examination
 This must include a meticulous examination ofThis must include a meticulous examination of
all soft tissues, shape of the ridges, and theall soft tissues, shape of the ridges, and the
amount of bone loss.amount of bone loss.
 Where gross bone loss precludes the use ofWhere gross bone loss precludes the use of
conventional fixed partial dentures, precisionconventional fixed partial dentures, precision
attachments can often overcome the problem.attachments can often overcome the problem.

 The teeth should be examined for caries, theThe teeth should be examined for caries, the
extent of restorations, colour, vitality,extent of restorations, colour, vitality,
angulations, mobility and bony support,angulations, mobility and bony support,
tenderness.tenderness.
 Consideration should be given to increase theConsideration should be given to increase the
length of crown sufficient for the provision oflength of crown sufficient for the provision of
a fixed partial denture or precision attachment.a fixed partial denture or precision attachment.
 A full periodontal survey should be carriedA full periodontal survey should be carried
out.out.

Occlusal analysisOcclusal analysis
The basic principles of occlusion should beThe basic principles of occlusion should be
applied to the analysis of each case. Theseapplied to the analysis of each case. These
are ,are ,
 There should be a stable co-ordinated occlusalThere should be a stable co-ordinated occlusal
contact of the maximum number of teeth incontact of the maximum number of teeth in
centric relation.centric relation.
 Forces ideally be in line with the long axis ofForces ideally be in line with the long axis of
each teeth.each teeth.

 There should be no non working inclineThere should be no non working incline
contacts.contacts.
 There must be a balance of anterior andThere must be a balance of anterior and
posterior inclines.posterior inclines.

RadiographsRadiographs
 Radiographs are essential for assessing theRadiographs are essential for assessing the
suitability of teeth and their supportingsuitability of teeth and their supporting
structures for abutments and the retainer ofstructures for abutments and the retainer of
precision attachments.precision attachments.

The free-end saddleThe free-end saddle
 These are classified in toThese are classified in to
 Bilateral free-end saddleBilateral free-end saddle
 And unilateral free-end saddleAnd unilateral free-end saddle
 Extracoranal attachments are preferred againstExtracoranal attachments are preferred against
intracoronal attachments.intracoronal attachments.

Bilateral free-end saddle denturesBilateral free-end saddle dentures

Unilateral free-end saddlesUnilateral free-end saddles
 Unilateral saddles can be used in an otherwiseUnilateral saddles can be used in an otherwise
intact arch ,or in combination with a boundedintact arch ,or in combination with a bounded
saddle on the opposite side of the arch.saddle on the opposite side of the arch.

CaseCase

The bounded saddleThe bounded saddle
 Bounded saddles can arise in either theBounded saddles can arise in either the
anterior or posterior part of the mouth.anterior or posterior part of the mouth.
 They can be found in combination with free-They can be found in combination with free-
end saddles or with bounded saddles on theend saddles or with bounded saddles on the
same arch.same arch.
 These are easier to treat than free-end saddles.These are easier to treat than free-end saddles.

Anterior bounded saddlesAnterior bounded saddles
 Problems which might arise in this situationProblems which might arise in this situation
and complicate the provision of conventionaland complicate the provision of conventional
fixed partial dentures could be due to:fixed partial dentures could be due to:
 Bone lossBone loss
 Unit spacingUnit spacing
 Lack of parallelism of abutment teeth andLack of parallelism of abutment teeth and
preparation.preparation.

Bone lossBone loss
 Where bone loss has been only slight and aWhere bone loss has been only slight and a
gum fitted fixed partial denture is acceptablegum fitted fixed partial denture is acceptable
in appearance, no problem arises.in appearance, no problem arises.
 Small deficiencies can be corrected by addingSmall deficiencies can be corrected by adding
pink porcelain between the pontics.pink porcelain between the pontics.

Bone lossBone loss
case 1 case 2case 1 case 2

Posterior bounded saddlesPosterior bounded saddles

Case-1Case-1

Over denturesOver dentures
 Anchors or stud attachments:Anchors or stud attachments:
Are made in rigid form for bounded saddleAre made in rigid form for bounded saddle
situations and in resilient form for free –endsituations and in resilient form for free –end
saddles.saddles.
They are generally used in conjuction withThey are generally used in conjuction with
posts and diaphragms placed in root canalsposts and diaphragms placed in root canals
following root canal therapy.following root canal therapy.
Anchors are usually retained by means ofAnchors are usually retained by means of
posts with diaphragms.posts with diaphragms.

Bar attachmentsBar attachments
 Spaced teeth which are splinted by a bar are mutuallySpaced teeth which are splinted by a bar are mutually
supportive.supportive.
 Burnout resin patterns are available and custom-madeBurnout resin patterns are available and custom-made
bars can be milled in the laboratory.bars can be milled in the laboratory.
 There are two types of bar—round and egg shaped.There are two types of bar—round and egg shaped.
 One advantage of round bar is that it can be bent inOne advantage of round bar is that it can be bent in
all directions.all directions.
 The egg shaped bar has extra rigidity making bindingThe egg shaped bar has extra rigidity making binding
more difficult.more difficult.

Case-2Case-2

Auxiliary attachmentsAuxiliary attachments
 a wide variety of attachments all in to thisa wide variety of attachments all in to this
category.these are:category.these are:
1.screw and tube1.screw and tube
2.key and keyway2.key and keyway
3.presso-matic or ipsoclip3.presso-matic or ipsoclip
4.sectional denture4.sectional denture

Key and keywayKey and keyway

Pressomatic or ipsoclipPressomatic or ipsoclip

Sectional denturesSectional dentures

Milling using a precisionMilling using a precision
parallelometerparallelometer
 The milling of crowns isThe milling of crowns is
a precise procedure fora precise procedure for
creating bracing, ledgescreating bracing, ledges
and rests in full orand rests in full or
partial veneer crownspartial veneer crowns
which serve to retainwhich serve to retain
conventional removableconventional removable

Milling processMilling process

The use of precision attachmentsThe use of precision attachments
with implantswith implants
 Use of precision attachments , in conjunctionUse of precision attachments , in conjunction
with the Esthetic cone abutment and the Steri-with the Esthetic cone abutment and the Steri-
Oss PME abutment, to overcome alignmentOss PME abutment, to overcome alignment
problems between implants and teeth.problems between implants and teeth.

EsthetiCone abutmentsEsthetiCone abutments
 The estheticone abutment has an overall heightThe estheticone abutment has an overall height
of 6.7mm and the abutment collars are eitherof 6.7mm and the abutment collars are either
1, 2 or 3mm in height so that marginal1, 2 or 3mm in height so that marginal
placement can be varied to give the bestplacement can be varied to give the best
esthetic results.esthetic results.
 The interocclusal space must be sufficient toThe interocclusal space must be sufficient to
accommodate the height of the abutment asaccommodate the height of the abutment as
well as the superstructure, otherwise it cannotwell as the superstructure, otherwise it cannot
be used.be used.

Short cantilever fixed partialShort cantilever fixed partial
dentures and overdentures:dentures and overdentures:
 If short implants are placed in the anterior partIf short implants are placed in the anterior part
of the mandible in a very shallow curvature, itof the mandible in a very shallow curvature, it
is unwise to cantilever more than a single unitis unwise to cantilever more than a single unit
distally as stresses would be transferred to thedistally as stresses would be transferred to the
screw and fixtures.screw and fixtures.
 The design in the following case allows for aThe design in the following case allows for a
complete restoration of the mandibular arch.complete restoration of the mandibular arch.

PME abutmentsPME abutments
 The PME abutmentsThe PME abutments
comes in the lengths ofcomes in the lengths of
2, 3, 4, 5 or 6mm.2, 3, 4, 5 or 6mm.
 It is made of titaniumIt is made of titanium
alloy and is capable ofalloy and is capable of
as much as 40as much as 40
misalignment correctionmisalignment correction
between implants.between implants.

Applications are:Applications are:
1.Fixed-removable full arch reconstructions on1.Fixed-removable full arch reconstructions on
six or more attachments.six or more attachments.
2.Overdentures supported on implants attached2.Overdentures supported on implants attached
to bar on four to six implants.to bar on four to six implants.
3.Tissue supported overdentures attached to a3.Tissue supported overdentures attached to a
bar on two implants.bar on two implants.
4.Fixed-removable partial denture on two or4.Fixed-removable partial denture on two or
more implants.more implants.
5.Fixed-removable partial denture attached to5.Fixed-removable partial denture attached to
natural teeth with precision attachment.natural teeth with precision attachment.

InterlocksInterlocks
 Interlocks are extremely useful in restorativeInterlocks are extremely useful in restorative
dentistry as they allow a degree of bothdentistry as they allow a degree of both
splinting and retrievability.splinting and retrievability.
 They are also relatively inexpensive.They are also relatively inexpensive.
 It is necessary to consider the extent andIt is necessary to consider the extent and
direction of the added force, the length anddirection of the added force, the length and
diameter of the implant, the quality of the bonediameter of the implant, the quality of the bone
and the angulation of the implants in that bone.and the angulation of the implants in that bone.

ConclusionConclusion
 The success of prostheses depends on carefulThe success of prostheses depends on careful
treatment planning and attention to the Prosthodontictreatment planning and attention to the Prosthodontic
problems. Careful use of precision attachments withproblems. Careful use of precision attachments with
emphasis on advantages, disadvantages, indications,emphasis on advantages, disadvantages, indications,
contraindications and mode of action is important forcontraindications and mode of action is important for
the success of treatment.the success of treatment.
 The dental surgeon who familiarizes himself withThe dental surgeon who familiarizes himself with
precision attachments will add new dimension to hisprecision attachments will add new dimension to his
treatment options.treatment options.

BibliographyBibliography
 Precision attachments-a link to successfulPrecision attachments-a link to successful
restorative treatment---Gareth Jenkins.restorative treatment---Gareth Jenkins.
 Precision attachments in Prosthodontics---Precision attachments in Prosthodontics---
preiskel.preiskel.
 Removable Partial Prosthodontics –Removable Partial Prosthodontics –
Ernest L. Miller & Joseph .E.Grasso.Ernest L. Miller & Joseph .E.Grasso.
 Essentials of complete denture ProsthodonticsEssentials of complete denture Prosthodontics
– Sheldon Winkler 2– Sheldon Winkler 2ndnd
edition.edition.

 Theory and Practice of Fixed Prosthodontics-Theory and Practice of Fixed Prosthodontics-
- Tylman.- Tylman.
 Prosthodontic treatment for edentulous Patients –Prosthodontic treatment for edentulous Patients –
-Zarb & Bolender.-Zarb & Bolender.
 Removable Partial Prosthodontics-Removable Partial Prosthodontics-
- Mc.Cracken’s.- Mc.Cracken’s.
 Removable Partial Prosthodontics-Removable Partial Prosthodontics-
- Stewart.- Stewart.

Thank youThank you

Precision attachments1 / dental implant courses by Indian dental academy

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