"rimar$ impression is made in sto% tra$ *or maing a stud$ %ast on 5#i%# a spe%ial tra$ is %onstru%ted+ Alginate is t#e impression material o* %#oi%e+ It is al5a$s 6est to *ollo5 t#e manufacturer+s instructions for manipulation +
,lastic Recoer": 97+: ; Remoal of the Tra": #e tra$ s#ould 6e remo3ed 5it# a s#arp snap parallel to t#e long a)is o* t#e toot# to redu%e permanent de*ormation and in%rease tear strengt# due to t#e 3is%o-elasti% nature o* t#e material+ Disinfection: Alginate impression must 6e poured 5it#in a s#ort time a*ter remo3al *rom mout#& disin*e%tion must 6e rapid to pre3ent dimensional %#anges& spra$ed on t#e e)posed sur*a%e not immersed+ Compatibilit" -ith die material: - asil$ remo3ed *rom die and do not need separating medium+
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Pouring the Primar" Cast )sing Dental Plaster. #e %ast s#ould 6e poured immediatel" to o6tain 6est results+ #e impression s#ould 6e remo3ed *rom t#e %ast and not le*t *or long time !not to a
/ater0Po-der ratio is 0-=0 ml/100 g Penetration tests: B$ needles 5#i%# #a3e a spe%i>% 5eig#t and de>nite tip diameter - icat needles: *or measuring initial setting time - $illmore needle: *or measuring initial and >nal setting times Factors accelerating the setting time: - ?o5 /" ratio - In%reased mi)ing time and rate - emperature 20-0 °C
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Sure"ing the primar" %ast to determine t#e pat# o* insertion+
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Tripoding the primar" cast +
2.*dapting a spacer and fabricating the special tra" oer the primar" cast.
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#e %ustom !spe%ial' tra$ is %ommonl$ made 6$ chemicall" cured acr"lic resins+ S#ould 6e -ell adapted on t#e primar$ %ast+
Free of oids and nodules on t#e sur*a%e *a%ing t#e tissues+ #e tra$ 6orders s#ould 6e smooth and rounded+ Maing t#e tra$ 6orders 2mm t#i% 5ill redu%e t#e @e)i6ilit$ and mae t#e border molding easier+
Proiding relief to %ertain areas
3.(a#ing the secondar" impression. •
Se%ondar$ impression is made in a spe%ial tra$ *or maing a master %ast on 5#i%# t#e denture is %onstru%ted+
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Border moulding using green stic# compound.
.e%ording t#e posterior palatal seal. Trimming t#e e)%ess green sti% %ompound+ Scraping out t#e 5a) spa%er in t#e spe%ial tra$+ Proiding relief holes o3er areas 5#ere additional relie* is reuired+ Maing t#e se%ondar$ impression using 4inc o%ide eugenol Impression paste.
5. Pouring the (aster Cast )sing Dental Stone0 Improed Stone
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Beading t#e se%ondar$ impression using 6eading0modeling -a%.
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Bo)ing t#e se%ondar$ impression using 6o%ing or modeling -a%.
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"ouring t#e master %ast using Dental stone.
7. Fabricating the temporar" denture base using shellac or acr"lic.
Fabricating occlusal rims using modeling -a%.
8. Recording the tentatie 9a- relation ertical 9a- relation Centric or !ori4ontal 9a- relation
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1=. Face bo- transfer and *rticulation
11. *nterior teeth arrangement. •
#en *a6ri%ating a %omplete denture& t#e step *ollo5ing arti%ulation is t#e arrangement o* teet#+ "rior to t#at& teet# sele%tion is
reuired+ •
It is a %ru%ial step as t#e sele%tion o* t#e %orre%t sie& s#ape& and %olour s#ade en#an%es t#e est#eti%s and t#e *un%tion o* t#e denture+
1'. *nterior Tr"in
1. Posterior teeth arrangement in balanced occlusion.
12. Tr"in eri>cation.
#is is t#e >nal %#an%e to ealuate the denture 5it# regards to >t& est#eti%s& midline& and o%%lusion !3erti%al and %entri%'+ #is is also t#e >rst time t#e patient #as to approe t#e denture+ DonCt lea3e t#e patient 5#ile t#e$ are 5earing 6ot# dentures& t#e$ ma$ 6ite do5n too #ard and mo3e t#e teet#+
13. /a% up •
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Is t#e pro%ess o* 5a)ing and %ar3ing o* t#e 5a) to t#e shape and contour o* a trial denture into t#e desired *orm #e pro%edure o* 5a)ing in3ol3es %ontouring t#e 5a) on t#e trial denture to produ%e a denture 6ase *orm t#at reprodu%es t#e %ontours o* t#e original tissues in t#e dentulous mout#+ Mae $our 5a)-up loo presentable.
The form of the polished surfaces and the proper location of the arti>cial teeth pla" a ma9or role in: - Sta6ilit$ o* t#e dentures - In@uen%es its retenti3e ualit$+ - In@uen%es t#e aest#eti% o* t#e denture+ - Support t#e %#ees& lips and tongue
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Do some artistic caring mae t#e 5a) smoot# and s#in$+
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*dd enough -a% to t#e teet# so t#e$ 5onCt *all out t#e >rst time t#e
patient o%%ludes+
15. Processing the denture Flasking It is the process of investing the cast with the waxed denture in a ask to make a sectional mold used to form the acrylic resin denture base.
Wax Elimination
Acrylic acking and then !easking
- #e resin s#ould 6e mi%ed in a clean 9ar and pac#ed -hen it reaches the dough stage+ - rial %losures s#ould 6e done till no ?ash is apparent on opening t#e @as - A*ter t#e resin #as rea%#ed t#e doug# stage& it s#ould 6e adapted to the mould -ith a cellophane sheet on it and %losed slo5l$ under a 6en%# press to permit t#e @o5 o* a%r$li% resin into t#e minute intri%a%ies o* t#e mold+ - #e mold s#ould 6e %ompletel$ >lled and ?ash e%truded during initial trial pa%ing+ - Failure to >ll the mold or under pac#ing can result in a denture -ith porosit"+ - Ideall$& the ?as# should be allo-ed to bench cure oernight to aoid porosities. - A*ter t#e denture #as 6een %ured& it is remo3ed *rom t#e %uring unit and allo5ed to 6en%# %ool+ - #e denture is t#en read$ *or recoer" *rom t#e in3estment mould - #e denture s#ould 6e retrie3ed along 5it# t#e %ast
Acryli"ation The denture can be cured b" either long curing c"cle or the short curing c"cle. Short Curing C"cle: #e denture is pla%ed in 5ater at room temperature and t#e %uring temperature is programmed to 70 E, *or 1+ #ours *ollo5ed 6$ 100 E, *or #al* an #our+ &ong Curing C"cle: #e %uring temperature is programmed to 70 E, *or 9 #ours+
17. Finishing and Polishing the Denture •
Finishing t#e denture %onsists o* remo3ing an$ @as# o* a%r$li% resin at t#e denture 6order& an$ @as# or stone remaining around t#e teet#& and an$ nodules o* a%r$li% resin on t#e sur*a%e o* t#e denture 6ase resulting *rom pro%essing+ - #e @as# o* a%r$li% resin %an 6e remo3ed 6$ slo5l$ re3ol3ing ar6or
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Polishing %onsists o* maing t#e denture smoot# and gloss$ 5it#out %#anging its %ontour+
- Smoot#en all a%%essi6le sur*a%es 5it# a muslin 6u< 5#eel and 5et pumi%e+ - A *elt %one and pumi%e ma$ 6e used to smoot# t#e 3ault o* t#e upper denture - Fse 5et pumi%e on a 6rus# 5#eel to smoot#en t#e interpro)imal areas 5#i%# are not rea%#ed 6$ t#e 6u< 5#eel
18. Insertion The >nished denture should ful>ll: - "#$si%al needs reuired *or per*orming adeuate *un%tion 5it#out %ausing trauma to t#e supporting stru%tures+ - "#$siologi%al needs 6$ allo5ing t#e proper support needed 6$ t#e mus%les to pro3ide proper est#eti%+ - "s$%#ologi%al needs 6$ pro3iding proper *un%tion and est#eti%+
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,#e% *or proper >t and function+ i3e proper instructions+ .e%all a*ter 24 #ours to %#e% immediate changes+ .e>ne occlusal discrepancies i* an$+ ,all *or re3ie5 a*ter a -ee# +
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.e%all eer" to 5 months *or re3ie5+
Denture Defects Denture defects include: "orosit$& ,raing& and arpage
orosity - "resen%e o* oids 5it#in stru%ture o* resin - Porosit" can be of t-o t"pes: Internal or )ternal - Internal porosit" is due to 3oids 5it#in t#e stru%ture usuall$ at t#i%er portion - Cause: due to 3aporiation o* t#e monomer !100+8,' - Solution G long lo5 temperature %uring %$%le is re%ommended+
- ,%ternal porosit" is due porosities 5#i%# o%%ur near t#e sur*a%e o* denture+
Preention: - A3oidan%e o* sol3ent - "roper use o* separating media
- Metal moulds - Fse o* %ross lined a%r$li%
Warpage • •
Denture 5arpage is change in shape or >t of denture+ ,ause is incorporation of stress in dentureG -"a%ing in late doug# or ru66er$ stage+ -Stress indu%ed during %uring - Improper de@asing -.ise in temp 5#ile polis#ing -Immersion o* pro%essed denture in #ot 5ater+
References: • •
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Textbook of Prosthodontics By Nallaswamy, Pages: 10 – 1 e)t6oo o* ,omplete Denture "rost#odonti%s& B$ D+ ?+ Sarand#a& Sarand#a D+ ?+& air Jussain& Ft#ars#& Pages: 12 - 1:0 Introdu%tion to Dental Materials 4G Introdu%tion to Dental Materials& Pages: 17= H 179 Introdu%tion to Dental Materials 4G Introdu%tion to Dental Materials& Pages: 142 - 144
