Design consideration in acrylic partial denture/ cosmetic dentistry training
DESIGN CONSIDERATION INDESIGN CONSIDERATION IN
ACRYLIC PARTIAL DENTURE.ACRYLIC PARTIAL DENTURE.
INDIAN DENTAL ACADEMY
Leader in continuing dental education
Various type of denture designed forVarious type of denture designed for
partially edentulous patients using varietiespartially edentulous patients using varieties
of denture base material.of denture base material.
Although the cast partial dentures are moreAlthough the cast partial dentures are more
accurate and satisfactory, more of acrylicaccurate and satisfactory, more of acrylic
partial dentures are used because of itspartial dentures are used because of its
simplicity and various other factors.simplicity and various other factors.
The frequency of acrylic partial denture isThe frequency of acrylic partial denture is
more than 90 to 95% in routine clinicalmore than 90 to 95% in routine clinical
cases when compared to cast partialcases when compared to cast partial
NEED FOR ACRYLIC PARTIALNEED FOR ACRYLIC PARTIAL
SOCIOECONOMIC STATUS ; Most of theSOCIOECONOMIC STATUS ; Most of the
patient prefer acrylic partial denturepatient prefer acrylic partial denture
because, they are less expensive whenbecause, they are less expensive when
compared to others.compared to others.
They can be constructed in any casesThey can be constructed in any cases
irrespective of the length of span or theirrespective of the length of span or the
condition of the adjoining hard and softcondition of the adjoining hard and soft
In young patients where extensive toothIn young patients where extensive tooth
preparation is not advisable as well as inpreparation is not advisable as well as in
old patients whose health contraindicatesold patients whose health contraindicates
the lengthy and physically tryingthe lengthy and physically trying
Because of the most expensive laboratoryBecause of the most expensive laboratory
equipments and technique sensitivity of theequipments and technique sensitivity of the
cast partial dentures.cast partial dentures.
When there is need for replace teethWhen there is need for replace teeth
immediately after their extraction.immediately after their extraction.
Relining and rebasing can be possible.Relining and rebasing can be possible.
All these factors makes necessity forAll these factors makes necessity for
construction of acrylic partial denture.construction of acrylic partial denture.
The three dimensional denture teeth mayThe three dimensional denture teeth may
have life like appearancehave life like appearance
When aesthetic is of primary concern .ItsWhen aesthetic is of primary concern .Its
possible to attain a more natural toothpossible to attain a more natural tooth
position by placing a denture tooth on aposition by placing a denture tooth on a
denture base.denture base.
Factor influencing the constructionFactor influencing the construction
of better acrylic partial denture.of better acrylic partial denture.
Nature of support.Nature of support.
It is classified as.It is classified as.
1). Tooth borne.1). Tooth borne.
2). Tooth and mucosa2). Tooth and mucosa
Tooth borne dentures canTooth borne dentures can
carry loads nearly equalcarry loads nearly equal
to those normallyto those normally
imposed on natural teeth.imposed on natural teeth.
A mucosa borne upperA mucosa borne upper
denture can usually spreaddenture can usually spread
the vertical load tothe vertical load to
underlying mucosa.underlying mucosa.
Larger the area covered byLarger the area covered by
the mucosa borne denturethe mucosa borne denture
the smaller the load perthe smaller the load per
unit area for any givenunit area for any given
It is reasonable to assumeIt is reasonable to assume
that it is impossible tothat it is impossible to
construct a denture in suchconstruct a denture in such
a way that vertical load isa way that vertical load is
evenly distributed b/w theevenly distributed b/w the
teeth and mucosa.teeth and mucosa.
Diagnosis and treatment plan.Diagnosis and treatment plan.
Diagnosis and treatment plan begin with aDiagnosis and treatment plan begin with a
thorough health history and history of pastthorough health history and history of past
dental experience.dental experience.
The complete oral examination mustThe complete oral examination must
include both clinical and roentgen graphicinclude both clinical and roentgen graphic
interpretation of endodontic, periodontalinterpretation of endodontic, periodontal
and surgical consideration.and surgical consideration.
Additionally, evaluation of occlusal plane,Additionally, evaluation of occlusal plane,
the arch form and the occlusal relationshipthe arch form and the occlusal relationship
of the remaining natural teeth must beof the remaining natural teeth must be
meticulously accomplished.meticulously accomplished.
After the complete examination has beenAfter the complete examination has been
accomplished ,and a removable acrylicaccomplished ,and a removable acrylic
partial denture has been agreed.partial denture has been agreed.
Then a treatment plan and a design canThen a treatment plan and a design can
be developed and sequenced that isbe developed and sequenced that is
based on the support available for thebased on the support available for the
partial denture.partial denture.
Sufficient difference exist between toothSufficient difference exist between tooth
supported and tooth and tissuesupported and tooth and tissue
supported acrylic partial denture.supported acrylic partial denture.
1)1) Manner in which the prosthesis isManner in which the prosthesis is
2)2) Type and extent of mouth preparation.Type and extent of mouth preparation.
Impresion procedure.Impresion procedure.
Almost all acrylic partialAlmost all acrylic partial
dentures take support fromdentures take support from
the underlying mucosa.the underlying mucosa.
Simple alginate impressionSimple alginate impression
will not be sufficient towill not be sufficient to
record the tissue in bothrecord the tissue in both
functional and anatomicalfunctional and anatomical
So dual impression is mustSo dual impression is must
in case of acrylic partialin case of acrylic partial
denture base design.denture base design.
Surveying is an importantSurveying is an important
procedure not only for castprocedure not only for cast
partial dentures but also forpartial dentures but also for
acrylic partial dentures.acrylic partial dentures.
The prime purpose ofThe prime purpose of
surveying is locate thesurveying is locate the
under cut for the path ofunder cut for the path of
insertion and removal.insertion and removal.
To locate the position ofTo locate the position of
the clasp below the heightthe clasp below the height
of contour.of contour.
it will demonstrate underit will demonstrate under
cut area which can becut area which can be
used for retention of theused for retention of the
Surveying isSurveying is
accomplished by holdingaccomplished by holding
a vertical marking edgea vertical marking edge
such as graphite rod insuch as graphite rod in
contact with the crown ofcontact with the crown of
the tooth and movingthe tooth and moving
either the cast or rod, soeither the cast or rod, so
that the side of graphitethat the side of graphite
draws a line around thedraws a line around the
circumference of thecircumference of the
crown. also to measurecrown. also to measure
soft tissue and bonysoft tissue and bony
Component of acrylic partialComponent of acrylic partial
Unlike cast partial denture, acrylic partial dentureUnlike cast partial denture, acrylic partial denture
contains onlycontains only
1) Acrylic denture base1) Acrylic denture base
2) Teeth2) Teeth
3) Direct retainer( clasps).3) Direct retainer( clasps).
Acrylic denture base.Acrylic denture base.
The purpose of denture baseThe purpose of denture base
is for unification ofis for unification of
Secondly it serves asSecondly it serves as
retentive factors. It acts asretentive factors. It acts as
major, minor connector andmajor, minor connector and
some times as indirectsome times as indirect
Distribution of the load evenlyDistribution of the load evenly
over the underlying mucosa.over the underlying mucosa.
Stabilization of the denture byStabilization of the denture by
resisting the horizontal forces.resisting the horizontal forces.
Natural retentive factors.Natural retentive factors.
Frictional resistance bw theFrictional resistance bw the
denture and lingual surfacedenture and lingual surface
of the posterior tooth.of the posterior tooth.
The contour of the hardThe contour of the hard
palate and character of thepalate and character of the
palatal mucosa.palatal mucosa.
Interfacial surface tensionInterfacial surface tension
b/w the denture base andb/w the denture base and
Area of coverage of theArea of coverage of the
denture base.denture base.
Design consideration in denture base.Design consideration in denture base.
Design of the denture baseDesign of the denture base
mainly depends on the nature ofmainly depends on the nature of
the support or extent ofthe support or extent of
edentulous space.edentulous space.
The denture base well extendedThe denture base well extended
into the interproximal areas andinto the interproximal areas and
onto the tooth surface above theonto the tooth surface above the
survey line.survey line.
Always the denture base shouldAlways the denture base should
be extended bilaterally.be extended bilaterally.
In case small edentulous spaceIn case small edentulous space
the orthoplated design can bethe orthoplated design can be
The denture base canThe denture base can
be extended onto thebe extended onto the
cingulum the anteriorcingulum the anterior
teeth for the indirectteeth for the indirect
It should be of sufficientIt should be of sufficient
thickness to avoidthickness to avoid
distortion duringdistortion during
The denture baseThe denture base
should be large enoughshould be large enough
to prevent aspiration.to prevent aspiration.
Also it should be radioAlso it should be radio
opaque to detect in suchopaque to detect in such
Teeth selection.Teeth selection.
Teeth selection can beTeeth selection can be
broadly classified asbroadly classified as
Anterior teethAnterior teeth
posterior teeth.posterior teeth.
customized teeth are mostcustomized teeth are most
preferable than pre –preferable than pre –
fabricated teeth.fabricated teeth.
pre fabricated teeth can bepre fabricated teeth can be
selected based onselected based on
material, shade andmaterial, shade and
acrylic teeth are moreacrylic teeth are more
preferred as they can bepreferred as they can be
customized accordingcustomized according
opposite natural teeth.opposite natural teeth.
Scraping of the ridge helps intimate contactScraping of the ridge helps intimate contact
of the teeth with the underlying tissueof the teeth with the underlying tissue
The buccolingual width of teeth selectedThe buccolingual width of teeth selected
should be smaller than opposing naturalshould be smaller than opposing natural
Modification of acrylic teeth.
acrylic teeth with amalgam stopsacrylic teeth with amalgam stops;;
amalgam is condensed on the preparedamalgam is condensed on the prepared
acrylic teeth. This prevents wearing ofacrylic teeth. This prevents wearing of
acrylic teeth.acrylic teeth.
IPN ( Inter penetrating polymer network ).IPN ( Inter penetrating polymer network ).
it has got quality of acrylic and porcelain.it has got quality of acrylic and porcelain.
And it said to be less wearable than acrylic.And it said to be less wearable than acrylic.
Direct retainer.Direct retainer.
The components that engages anThe components that engages an
abutment tooth and in doing so resistabutment tooth and in doing so resist
dislodging forces applied to a removabledislodging forces applied to a removable
partial denturepartial denture
It is generally preferable not employ clasp toIt is generally preferable not employ clasp to
retain the partial denture unless naturalretain the partial denture unless natural
retentive factors are exceedinglyretentive factors are exceedingly
Clasps will strain the abutment tooth due toClasps will strain the abutment tooth due to
improper tooth preparation and claspimproper tooth preparation and clasp
Caries may develop beneath the claspCaries may develop beneath the clasp
component, especially if the patient fails tocomponent, especially if the patient fails to
keep the prosthesis clean.keep the prosthesis clean.
Clasp can be made eitherClasp can be made either
of wrought wire or castableof wrought wire or castable
clasp or combination ofclasp or combination of
both .both .
The most common designThe most common design
employed is the simpleemployed is the simple
circlet clasp with 18 gaugecirclet clasp with 18 gauge
Material used for clasp.Material used for clasp.
wrought alloy wire iswrought alloy wire is
superior to cast by virtue ofsuperior to cast by virtue of
its internal structure. It isits internal structure. It is
more flexible, minimummore flexible, minimum
friction compared castfriction compared cast
Requirements of clasp design.Requirements of clasp design.
Retention ; to provideRetention ; to provide
retention againstretention against
dislodging forces.dislodging forces.
The amount of retention isThe amount of retention is
depends ondepends on
The amount of clasp armThe amount of clasp arm
that extends below thethat extends below the
height of contourheight of contour
The depth that retentiveThe depth that retentive
terminal extends into theterminal extends into the
under cut.under cut.
Flexibility.; it's a mostFlexibility.; it's a most
variable factor invariable factor in
determining retention.determining retention.
Greater the length greaterGreater the length greater
will be flexibilitywill be flexibility
It is inversely proportionalIt is inversely proportional
to the diameter of clasp.to the diameter of clasp.
Cross sectional form.Cross sectional form.
Material of the clasp;Material of the clasp;
wrought alloy are morewrought alloy are more
flexible when compared toflexible when compared to
cast alloy.cast alloy.
Positioning of the clasp.Positioning of the clasp.
Encirclement.; claspEncirclement.; clasp
should be designed toshould be designed to
encircle more thanencircle more than
180*(more than half of180*(more than half of
the tooth.)the tooth.)
Passivity. A clasp mustPassivity. A clasp must
be completely seated onbe completely seated on
a tooth to be passive.a tooth to be passive.
Location of the retentiveLocation of the retentive
It should be placedIt should be placed
such that resultant forcesuch that resultant force
should fall near center ofshould fall near center of
gravity of denture.gravity of denture.
Modification in clasp design.Modification in clasp design.
Double wire clasp.Double wire clasp.
Indicated when the gaugeIndicated when the gauge
of the wire is less.of the wire is less.
Ball end clasp; whenBall end clasp; when
undercuts are not presentundercuts are not present
for conventionalfor conventional
clasp(0.040 inch).clasp(0.040 inch).
Zig zag shaped clasp;Zig zag shaped clasp;
they also acts as occlusalthey also acts as occlusal
Single wire clasp withSingle wire clasp with
blunt end. (thick gauge)blunt end. (thick gauge)
Try in acrylic partial denture.Try in acrylic partial denture.
A try-in appointment shouldA try-in appointment should
be used on a routine basisbe used on a routine basis
for acrylic partial denture.for acrylic partial denture.
The patient should beThe patient should be
seated in a pleasant, quiet,seated in a pleasant, quiet,
room to alleviateroom to alleviate
unnecessary tension.unnecessary tension.
Try in helps in correction inTry in helps in correction in
tooth size, tooth position, ortooth size, tooth position, or
tooth shade can betooth shade can be
Also verification of the jawAlso verification of the jaw
relation records that wererelation records that were
made at last appointments.made at last appointments.
Denture base is waxed toDenture base is waxed to
neat anatomicneat anatomic
Anterior teeth must beAnterior teeth must be
looked for adequate liplooked for adequate lip
support and naturalsupport and natural
Accurate vertical andAccurate vertical and
horizontal overlap must behorizontal overlap must be
Midline, formed byMidline, formed by
proximal surface ofproximal surface of
incisors must be inincisors must be in
harmony with midline ofharmony with midline of
Trimming and polishing partial dentureTrimming and polishing partial denture
Three areas of primaryThree areas of primary
1).external surface of1).external surface of
denture base.denture base.
2).periphery or borders of2).periphery or borders of
denture base.denture base.
3) finish lines or contact3) finish lines or contact
area b/w teeth andarea b/w teeth and
denture base.denture base.
Care should be taken notCare should be taken not
create dead spaces orcreate dead spaces or
leading food trapment.leading food trapment.
Insertion of partial denture.Insertion of partial denture.
Correcting the fit of theCorrecting the fit of the
denture base to thedenture base to the
edentulous ridge.(pressureedentulous ridge.(pressure
indicating paste.)indicating paste.)
To correct the occlusalTo correct the occlusal
To adjust the retentive claspTo adjust the retentive clasp
if necessary.if necessary.
To instruct the patient inTo instruct the patient in
home care and care of thehome care and care of the
Post insertion observation.Post insertion observation.
Soft tissue irritation,lacerationSoft tissue irritation,laceration
or ulceration.or ulceration.
Use the pressure indicatingUse the pressure indicating
paste to locate and relivepaste to locate and relive
the area.the area.
Irritation to teeth due toIrritation to teeth due to
pressure from partialpressure from partial
denture.(disclosing wax).denture.(disclosing wax).
Articulating papers are usedArticulating papers are used
to locate the area ofto locate the area of
occlusal interference.occlusal interference.
Check for problems withCheck for problems with
Correction of cheek orCorrection of cheek or
tongue biting.tongue biting.
Can be corrected byCan be corrected by
rounding mandibularrounding mandibular
buccal cusp.buccal cusp.
Difficulty in chewing.Difficulty in chewing.
Loose denture.- becauseLoose denture.- because
retentive clasp tip thatretentive clasp tip that
were not adjustedwere not adjusted
accurately or completelyaccurately or completely
into the undercut area.into the undercut area.