tikrit university college of dentistry dr. reem ahmed shehab lec … · 2017-11-14 · lec-6-...
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Tikrit University College of Dentistry – Dr. Reem Ahmed Shehab Lec-6- prosthodontics 3rd class
cden.tu.edu.iq
Mandibularmajorconnector Specialstructuralrequirement
Ingeneral,mandibularmajorconnectorsarelongandnarrow,thereforespecialconsiderationmustbegiventothedesignofsuchconnectors.
Reliefisprovidedforsofttissueunderallportionsofmandibularmajorconnectorandanylocationwheretheframeworkcrossthegingivalmargin.Theinferiorborderofalingualmandibularmajorconnectormustbelocated,sothatitdoesnotimpingeonthetissueinthefloorofthemouthbecauseitchangeselevationsduringthenormalactivitiesofmastication,swallowing,speaking,lickingthelips---etc.Themetalshouldbehighlypolishedonthetissuesidetominimizeplaqueaccumulation.
Itisimportanttonotethatbeadlinesarenotusedinconjunctionwithmandibularmajorconnector.Contactwithfriablemucosaofthemandibulararchmaycauseirritation,ulcerationandpatientdiscomfort.
Sixtypesofmandibularmajorconnectorsare:
1-Lingualbar.
2-Linguoplate(lingualplate).
3-Sublingualbar.
4-Lingualbarwithcingulumbar(doublebar).
5-Cingulumbar.
6-Labialbarandbuccalbar.
Tikrit University College of Dentistry – Dr. Reem Ahmed Shehab Lec-6- prosthodontics 3rd class
cden.tu.edu.iq
Lingualbar&lingualplatemajorconnectorsareusedinthemajorityofremovablepartialdentureapplications.Doublelingualbarandlabialbarmajorconnectorsareusedforspecialapplicationsinwhichlingualbarsandlingualplatesarecontraindicated.
lbarlingua-1 Isthemostfrequentlyusedmandibularmajorconnector,becauseofitssimplicityindesignandconstruction.
Indication: Itisthefirstchoicemajorconnector,shouldbeusedwheneverthefunctionaldepthfromfreegingivalmargintothelingualvestibuleequalorexceed8mm.
Design: 1.thebarshouldbehalfpear-shapedincrosssection.superiorinferiordimensionis5mm,and2mminthickness. 2.thesuperiorborderofthebarshouldbelocatedatleast3mmfromthegingivalmarginsofalladjacentteeth. 3.theinferiorborderplacedatthefunctionaldepthofthelingualvestibule. 4.relifofthetissuesurfaceofthebarisnecessary.
Tikrit University College of Dentistry – Dr. Reem Ahmed Shehab Lec-6- prosthodontics 3rd class
cden.tu.edu.iq
:dvantagesA 1.thesimplestmandibularmajorconnectorwithhighestpatientacceptance. 2.itdoesnotcovertheteethorthegingivaltissues disadvantages: Ifitisnotproperlydesigneditmaynotberigid.
lingualplate-2 Half–pearshapedlingualbarwithathin,solidpieceofmetalextendingfromitssuperiorborder.thisthinprojectionofmetaliscarriedontothelingualsurfacesoftheteethandpresentsascallopedappearance.
Theinferiorborderofalingualplateshouldbepositionedaslowinthefloorofthemouthaspossible.butshouldnotinterferewiththefunctionalmovementsofthetongueandsofttissues.
Thesuperiorborderofalingualplatemustbecontouredtointimatelycontactthelingualsurfacesoftheteethabovethecingula.
Tikrit University College of Dentistry – Dr. Reem Ahmed Shehab Lec-6- prosthodontics 3rd class
cden.tu.edu.iq
s:Indication 1-usedwhenthereisinsufficientverticalspaceforalingualbar(distancefromfreegingivalmargintofloorofthemouthlessthan8mm)
2-whenthereisgingivalrecession,highmuscleattachmentsorhighfrenumattachmentsonthelingualaspectofthemandibulararch.
3-whentheremainingteethhavelostmuchoftheirperiodontalsupportandrequiresplinting.Lingualplateusedtostabilizetheremainingteethandtodistributeappliedforcesovertheremainingteethandsofttissue.
4-lingualtoriispresent.
esadvantag 1.Themostrigidmandibularmajorconnector.
2.Itgivesindirectretentiontothepartialdenture.
3.Deflectfoodfromimpactingonlingualtissues.
4.Provideresistanceagainsthorizontalorlateralforces.
5.Permitsthereplacementoflostteethwithoutremakingthepartialdenture. 6.Helpinsplintingandpreventupper-eruptionoftheanteriorteeth
Disadvantages: Inpatientwithpoororalhygiene,lingualplateextensivecoveragemaycontributetodecalcificationofenamelsurfacesandirritationofthesofttissueinpatientswithpoororalhygiene.
withcingulumbarlingualbar-Double-3 :Indications
1.Whenindirectretentionisrequired.
Tikrit University College of Dentistry – Dr. Reem Ahmed Shehab Lec-6- prosthodontics 3rd class
cden.tu.edu.iq
2.Whenperiodontallyaffectedteeththatrequiresplintingarepresent. :Design
1.Itismadeoftwobars;cingulambar(Kennedybar)andtheconventionallingualbar.Arigidminorconnectorattheembrasurebetweenthecanineandfirstpremolarsjoinsthetwobars.Restsareplacedateachendoftheupperbarattachedtotheminorconnector. 2.Thelowerbarhasthesamedesignasasinglelingualbar. 3.Theupperbarisscalloped,andhalf-ovalincrosssection(2-3mmhigh,and1mmthickatitsgreatestdiameter.
Advantages 1-provideindirectretention.
2-contributetohorizontalstabilization
3-nogingivalmargincoverage.
-:DISADVANTAGES
Tongueannoyance1
ntimatecontactwiththeteeth.foodimpactioniftheupperbarisnoti-2
Cingulumbar-4
Tikrit University College of Dentistry – Dr. Reem Ahmed Shehab Lec-6- prosthodontics 3rd class
cden.tu.edu.iq
Indications 1-heightofactivatedlingualfrenumandfloorofthemouthatthesamelevelasmarginalgingiva
2-inoperabletoriorexostosisatthesamelevelasthemarginalgingiva
3-severlyundercutlingualalveolus
4-considerablegingivalrecession.
SCONTRAINDICATION
1-anteriorteethseverelytiltedtothelingual
2-diastemaandopencervicalembrasureswherethemetalwillshow.
Advantages:
1-canbeusedwherelingualbarandlingualplatecannot.
2-doesnottransversethemarginalgingivaoroverlythelingualalveolus.
3-easytoaddprostheticteethtoframework.
-Disadvantages:
Tikrit University College of Dentistry – Dr. Reem Ahmed Shehab Lec-6- prosthodontics 3rd class
cden.tu.edu.iq
Mustbebulkytohavesufficientrigidityandthusmaybeobjectionabletothepatient.
labialbar-5 Indications:
1.Whenthemandibularteetharesoseverelyinclinedlinguallyastopreventtheuseoflingualmajorconnector.
.contraindicatedexistandtheirremovalis2.Whenlargelingualtori
Design:
1.Itisahalfpearshapedbar,runsacrossthemucosalabialtotheanteriorteeth.
2.Labialvestibuleshouldbeadequatetoallowthesuperiorbordertobeplacedatleast3mmbelowthefreegingivalmargins. 3.Reliefisrequiredbeneaththebar.
:Advantages
1-itsolvedtheproblemoflinguallyinclinedteeth&avoidsurgicalinterventiontoremovelargelingualtori
-:Disadvantages
lackofrigidity-1
leastcomfortabletopatient.-2
Tikrit University College of Dentistry – Dr. Reem Ahmed Shehab Lec-6- prosthodontics 3rd class
cden.tu.edu.iq