Download - DEFINITION: Any type of device used for stabilization or retention of prosthesis -- GPT RETAINERS
DEFINITION:DEFINITION:Any type of device
used for stabilization or retention of
prosthesis -- GPT
RETAINERS
Retainer for an FPD…Retainer for an FPD… That component of an FPD That component of an FPD
which takes support from the which takes support from the abutment tooth and provides abutment tooth and provides retention to the prosthesisretention to the prosthesis
SELECTION OF RETAINERSSELECTION OF RETAINERS Retainer selection for abutment is Retainer selection for abutment is
critical and is dictated by the critical and is dictated by the followings:followings:
1)1) AgeAge2)2) DMF rateDMF rate3)3) Edentulous space-Partial veneer crown Edentulous space-Partial veneer crown
contraindicated in long span FPDcontraindicated in long span FPD4)4) Periodontal supportPeriodontal support5)5) Arch position of the toothArch position of the tooth6)6) Skeletal relationship Skeletal relationship
7)7) Inter occlusal & intraocclusal Inter occlusal & intraocclusal condition such as crown lengthcondition such as crown length
8)8) Oral hygiene of the patientOral hygiene of the patient
9)9) Vitality of the abutment teeth---Vitality of the abutment teeth---endodontically treated teeth may endodontically treated teeth may have to be restored with core & have to be restored with core & post before designing the retainerpost before designing the retainer
10)10) Condition of the abutment teethCondition of the abutment teeth
11)11) CostCost
12)12) Preservation of the tooth Preservation of the tooth structure----Buccal surface should be structure----Buccal surface should be conserved. Partial veneer crown is conserved. Partial veneer crown is more conservative than full crown . more conservative than full crown . All ceramic crowns are least All ceramic crowns are least conservativeconservative
Types of retainersTypes of retainers Classified as:Classified as:
I.I. Based on tooth coverageBased on tooth coverage Full veneer crownFull veneer crown
Partial veneer crownPartial veneer crown
Conservative (minimal prep.) Conservative (minimal prep.) retainersretainers
II.II. Based on material usedBased on material usedAll metal retainersAll metal retainers
Metal ceramic retainersMetal ceramic retainers
All ceramic retainersAll ceramic retainers
All acrylic retainersAll acrylic retainers
Full veneer Full veneer crownscrowns
Covers all 5 surfaces of abutmentCovers all 5 surfaces of abutment Most retentive of the veneer Most retentive of the veneer
preparationspreparations Compared to partial veneer Compared to partial veneer
designs,full veneer crown exhibits designs,full veneer crown exhibits superior resistance nd retentionsuperior resistance nd retention
Used on those teeth whose Used on those teeth whose restoration demands max. retention.restoration demands max. retention.
Variations—Metal ceramic crowns and Variations—Metal ceramic crowns and all ceramic crowns used in situations all ceramic crowns used in situations that requires a good cosmetic resultsthat requires a good cosmetic results
The full veneer crown should be used The full veneer crown should be used when less extensive and less when less extensive and less destructive design have been destructive design have been considered and found lacking in considered and found lacking in retention ,resistance ,coverage or retention ,resistance ,coverage or esthetics to properly restore the toothesthetics to properly restore the tooth
Partial veneer Partial veneer crowncrown
Preferred than full veneer crown because Preferred than full veneer crown because they requires less tooth reductionthey requires less tooth reduction
Crown does not cover the entire abutmentCrown does not cover the entire abutment Facial surface is left intact for superior Facial surface is left intact for superior
estheticsesthetics Used when minimal retention is sufficient Used when minimal retention is sufficient
and when abutment tooth is healthyand when abutment tooth is healthy
Contra indicationsContra indications
In long span FPDsIn long span FPDs Endodontically treated toothEndodontically treated tooth Dentition with active caries or Dentition with active caries or
periodontal diseaseperiodontal disease Poorly aligned abutment toothPoorly aligned abutment tooth
AdvantagesAdvantages
Conservation of tooth structureConservation of tooth structure Reduced pulpal and periodontal Reduced pulpal and periodontal
insult during tooth prepinsult during tooth prep Improved access for finishing by Improved access for finishing by
dentist & oral hygiene by patientdentist & oral hygiene by patient
Less of margin approximate soft Less of margin approximate soft tissues subgingivally and hence less tissues subgingivally and hence less gingival involvement than complete gingival involvement than complete coveragecoverage
Remaining intact facial or buccal Remaining intact facial or buccal tooth surface permits electric vitality tooth surface permits electric vitality testtest
DisadvantagesDisadvantages Less retention & resistance than Less retention & resistance than
complete crownscomplete crowns Some metal displayed in completed Some metal displayed in completed
restoration—unaestheticrestoration—unaesthetic Tooth prep is difficult because only Tooth prep is difficult because only
limitedlimited
adjustments can be made in the path adjustments can be made in the path of placementof placement
Resin bonded retainersResin bonded retainers(Maryland bridges)(Maryland bridges)
Require minimal tooth Require minimal tooth preparationpreparation
Acid etchedAcid etched Esthetically appealingEsthetically appealing Economical , conservative , Economical , conservative ,
functional & do not irritate soft or functional & do not irritate soft or hard tissueshard tissues
IndicationIndication
As retainers of FPD for abutment As retainers of FPD for abutment with sufficient enamel to etchwith sufficient enamel to etch
Splinting of periodontally Splinting of periodontally compromised teethcompromised teeth
Stabilizing dentition after Stabilizing dentition after orthodontic treatmentorthodontic treatment
ContraindicationContraindication In patients with sensitivity to base In patients with sensitivity to base
metal alloysmetal alloys When facial esthetic of abutment When facial esthetic of abutment
require improvementrequire improvement Inadequate enamel surface to bond Inadequate enamel surface to bond
eg;caries,existing restorationeg;caries,existing restoration Incisor with extremely thin facio-Incisor with extremely thin facio-
lingual dimensionlingual dimension
AdvantagesAdvantages Non invasive to dentin with lingual and Non invasive to dentin with lingual and
proximal tooth preparation including proximal tooth preparation including occlusal restocclusal rest
Conservative with undeniable patient Conservative with undeniable patient appearanceappearance
Tissue tolerant because of Tissue tolerant because of Supragingival margin,without pulpal Supragingival margin,without pulpal irritationirritation
Reduced cost and less chair side timeReduced cost and less chair side time
DisadvantageDisadvantage Demanding technique and tooth Demanding technique and tooth
prep.prep. Plaque accumulationPlaque accumulation Bulky contourBulky contour Restricted to single pontic placementRestricted to single pontic placement Graying out of teeth that are thin Graying out of teeth that are thin
labiolinguallylabiolingually
Based on material usedBased on material used
All metal retainers All metal retainers Metal ceramic retainersMetal ceramic retainers All ceramic retainersAll ceramic retainers
All metal retainersAll metal retainers
Partial or full veneer crownPartial or full veneer crown Require minimal tooth Require minimal tooth
reductionreduction Strong even in thin Strong even in thin
sectionssections
Metal ceramic retainersMetal ceramic retainers
Indicated on teeth that require Indicated on teeth that require complete coverage & esthetic complete coverage & esthetic demanddemand
Can accommodate cast or Can accommodate cast or soldered connectorssoldered connectors
Can afford high force—metalCan afford high force—metal Require more teeth reductionRequire more teeth reduction
IndicationIndication
Extensive tooth destruction as a Extensive tooth destruction as a result of caries or traumaresult of caries or trauma
Existing previous restoration that Existing previous restoration that precludes the use of a more precludes the use of a more conservative restorationconservative restoration
Need for superior retention and Need for superior retention and strengthstrength
Endodontically treated toothEndodontically treated tooth
ContraindicationContraindication
Whenever a more Whenever a more conservative retainer conservative retainer is feasibleis feasible
All ceramicAll ceramic Primary purpose ---to achieve Primary purpose ---to achieve
best possible esthetic resultsbest possible esthetic results Risk of reduced restoration Risk of reduced restoration
longevity—potential for longevity—potential for fracture ,inferior marginal fracture ,inferior marginal adaptation than PFM retaineradaptation than PFM retainer
Telescopic Telescopic retainersretainers
Used when path of insertion of FPD does Used when path of insertion of FPD does not coincide with long axis of abutmentnot coincide with long axis of abutment
Design involves fabricatin of two copings Design involves fabricatin of two copings one over the otherone over the other
Internal or primary coping function to Internal or primary coping function to modify the morphology of tooth –path pf modify the morphology of tooth –path pf insrtn changedinsrtn changed
Secondary coping designed to fit over Secondary coping designed to fit over primary primary
REFERENCESREFERENCES
1.1. Fundamentals of Fixed ProsthodonticsFundamentals of Fixed Prosthodontics Herber T.ShillingburgHerber T.Shillingburg2.2. Contemporary Fixed ProsthodonticsContemporary Fixed Prosthodontics Rosenstiel,Land,FujimotoRosenstiel,Land,Fujimoto3.3. Tylmans Theory and Practice of Fixed Tylmans Theory and Practice of Fixed
ProsthodonticsProsthodontics4.4. Textbook of Prosthodontics-Deepak Textbook of Prosthodontics-Deepak
NallaswamyNallaswamy