Inlay, Onlay, Veneer Flashcards
what are indirect restorations
- restoration is fabricated outside of the mouth
- dental impression taken of prepared tooth then sent to lab or milled in office
what can indirect restorations be used for
- inlays
-onlays - crowns
- bridges
- veneers
what are the materials used for indirect restorations
- gold
- lithium disilicate- eMAX
when do you place indirect restorations
- when margin exceeds 2/3 of the distance between central groove and cusp tip - MUST CAP WEAK CUSPS
- when margins and 1/2 distance between central groove and cusp tip - CONSIDER CAPPING WEAK CUSPS
what is an inlay
indirect restoration that is placed within the cusp tips of a tooth
does an inlay offer protection of the cusp from occlusal forces
no
what are inlays used for
teeth with minimal caries and strong buccal and lingual cusps
- acceptable occlusion
what is an onlay
indirect restoration that covers one or more cusps, extending through and beyond the cusp tip to the facial/lingual and proximal slopes of the covered cusps
what principles does an onlay incorporate
the principles and advantages of both intracoronal and extracoronal indirect restorations
in onlays what is occlusion in all functional positions supported by
restorative material
what are the indications for onlays
- large carious lesions or existing defective restorations
- cracked teeth
- endo treated teeth
when can endo teeth be used for onlays
- sufficient tooth structure to retain the onlay and allow for removal of undercuts
- when enough facial and lingual surfaces are relatively intact- otherwise crown
when do you use an onlay instead of an inlay
- when the bucco-lingual width of the cavity prep is 1/2 way between central groove and cusp tip- consider onlay. OR 2/3 way between central groove and cusp tip- should onlay
- where the cusps are undermined after caries removal
- where the occlusion of the tooth must be altered
what is a crown
indirect restoration that fully covers the occlusal surface of a tooth and uses the external walls for retention
why do we do inlays and onlays
- preference over amalgam
- conserve tooth structure compared to crown
- esthetics
- RPD abutment
why do inlays and onlays for RPD abutments
can better control rest seats and guide planes
what are the disadvantages of indirect restoration
- expense
- requires 2 appointments if sent to a lab
- impression needed
what are the advantages of indirect restorations
- strength of materials
- conservation tooth structure
- better control of restorations contours
what are inlays made of
either gold or porcelain
what are the principles to follow for inlays
- no undercuts; passive fit
- no sharp line angles
what are the advantages of indirect gold
- strength: wont fracture
- wear resistance: will support contact and occlusion
- will maintain smooth surface
- better control of contact and contour
- potential for greater longevity
- conserves cementum and periodontal attachment versus restoring with a crown
what are the contraindications for indirect gold
- facial or lingual caries or previous restorations
- crown is better to restore multiple surfaces
- need to compare margin length with that of a crown - patients with high caries rate
how do you prepare a gold inlay
- divergence: short walls should have 2 degree divergence and long walls can have 5-7 degree divergence
- bevel: 1mm occlusal, axial pulpal line angle, 1mm gingival wall
- no sharp line angles
- dovetail
- no reverse S
- smooth proximal walls
- adequate proximal clearance of 0.5mm
how deep are gold inlay preps
2mm
what is the purpose of dovetail in inlay prep
prevents distal displacement
what is the purpose of the bevel
protects enamel from fracturing
what is the internal form of an indirect onlay
rounded line angles
what are the prep requirements for a ceramic inlay- occlusal depth, isthmus
- occlusal depth: 1.5-2mm
- isthmus: at least 2mm wide
- no undercuts
- pulpal walls = smooth and flat
- facial, lingual and gingival margins should clear contacts by at least 0.5mm
- facial and lingual walls must diverse
- need passive insertion and greater than a 2-5 degree taper
why must the isthmus be so large in ceramic inlays
decreases chance of fracture of restorative material
why can you have diverging walls in ceramic inlays
restoration bonds to preparation walls
what are onlays made with
gold or porcelain
when would you do an onlay instead of an inlay
when prep gets too wide, onlay buccal and/or lingual cusps
what is clearance
the amount of space between teeth
what is reduction
the amount of tooth structure removed
do you need occlusal clearance or reduction with onlays
clearance
what are the depth cuts for gold onlays
- 1.5mm on functional cusp
- 1.0mm on nonfunctional cusp
do you bevel the non functional cusp or functional cusp in gold onlays
both
what are the principles for gold onlays
- cover both facial and lingual cusps of maxillary and mandibular teeth
- minimum of 1.5mm of gold to cover cusps supporting occlusion; 1.0mm for cusps not supporting occlusion
- reverse bevel of 1-2mm on cusps supporting occlusion; 1/2 mm on cusps not supporting occlusion
what are the indications for porcelain onlays
- esthetics
- large defects or previous restorations
what is the exception for cuspal coverage on maxillary tooth
- do not cover the facial cusp of maxillary molar or premolar if supported by strong tooth structure
- modified esthetic coverage of facial cusp if weak
what large defects or previous restorations would indicate a porcelain onlay
- wide labiolingual missing tooth structure
-teeth that require cuspal coverage - contours of large restorations are more easily developed in the lab
- indirect materials are more durable than direct for replacing occlusion and contacts
what are the contraindications for porcelain onlays
- ceramics can fracture if they dont have sufficient bulk or are under excessive stress
- inability to maintain a dry field
- deep subgingival preparations- difficult to get impression, to finish and get good bonding
what are the advantages of porcelain onlays
- improved physical properties
- wear resistance
- reduced polymerization shrinkage
describe the wear resistance of porcelain
- porcelain wears opposing teeth the most and has the most resistance to wear
what is the order of what causes the most wear and wears the least to causes least wear and wears the most out of porcelain, lab processed composite, and direct resin composite
porcelain> lab processed composite > direct resin composite
where does polymerization shrinkage occur in porcleain onlays
- in the lab
- only material that can shink is the resin composite cement used in cementation
what are the disadvantages of porcelain onlays
- increased cost and time
- requires two patient appointments and a lab bill
- technique sensitivity- devotion to detail
- ceramics are brittle
- wear opposing dentition and restorations
- low potential for repair
- difficult try in and delivery
what is the clinical procedure for porcelain onlays
- remove old restorations
- excavate all caries
- undercuts are blocked out with a glass inomer liner/base or resin composite
- want rounded line angles to avoid stress concentration
- need adequate thickness for strength of porcelain
- well defined margins
- all margins should have a 90 degree butt joint cavosurface angle
- no external bevels
what are the reductions for porcelain onlays
- 2.0mm over functional cusps
- 1.5mm reduction over non functional cusp
-bulk of porcelain at margins- no bevel - smooth internal line angles
- no ferrule margins
- ceramic retention base on surface area not opposing walls
- 0.5mm for proximal margins
what are the provisional considerations
- use eugenol free cement
- eugenol interferes with bonding
- if must use cement with eugenol important to pumice the tooth to remove eugenol
when are occlusal evaluations and adjustments done
after cementation because of the fragility of porcelain restorations
what is silanation
porcelain is acid etched with hydrofluoric acid and then silanated before cementation with a resin cement
what instruments are used for finishing and polishing ceramics
- medium to fine grit diamond instrument
- 30 fluted carbide burs
- rubber, abrasive, impregnaated porcelain polishing points
- diamond polishing paste
why do you not want any scratches or rough spots on the porcelain
it will wear enamel severely
what are the types of veneers
- indirect: feldspathic porcelain or lithium disilicate
- direct: composite
what are the indications for veneers
- instrinsic discoloration: tetracycline staining, fluorosis
- extrinsic staining: coffee, smoking, wine
- wear patterns
- poor restorations
- diastema closure
- rotated and misaligned teeth
what are the contraindications for veneers
- severely malpositioned teeth
- denuded dentin
- unavailable enamel
- poor oral hygiene
- beware of highly fluoridated teeth - issues with bonding
- no primary teeth
- adolescents
- pregnancy
- oral habits: bruxism
what are the indications for veneers
- good oral hygiene
- good perio health
- poor esthetics
- proper patient psychology
- caries free
- met dental needs
- informed consent and reasonable expectations
what are the advantages of porcelain veneers
- esthetics are excellent
- color- porcelain is best tooth subsititue
- bond strength - high to enamel
- periodontal health
- low wear and abrasion of porcelain restorations
what are the disadvantages of porcelain veneers
- time: multiple appointments
- cost compared to composite veneers
- some tooth prep, must have adequate room
- requires lab involvement and fee
what is the alternate treatment to porcelain veneers
- bleaching for discoloration
- microabrasion and macroabrasion
- direct composite veneers
- PFM/porcelain jacket crown
- ortho
what composite resin polishes the best
microfill
what are the advantages of direct composite veneers
- mask discolorations on a tooth
- least cost to patient
- usually one appointment
- can correct simple tooth rotation and diastema easily
what are the disadvantages of composite (direct) veneers
- susceptible to wear
- margin fracture and stain
- discoloration
what are the composite veneer procedures
- window preparation
- incisal lapping preparation
describe window preparation
- most often recommened
- remove only enough tooth structure to achieve optimal contours with final restoration
- incisal edge remains intact
- intra enamel preparation
what does intra enamel preparation in window preparation do
- provides space for materials to achieve maximum esthetics
- removes outer, fluoride rich layer of enamel
- roughens surface for improved bonding
- establishes definite finish line
describe incisal lapping prep
- prep includes incisal edge
- indicated when tooth needs to be lengthened or an incisal defect is present
what does minimal tooth prep result in
overcontoured veneers
what is microabrasion
- involves use of acidic and abrasive agents applied to enamel surface
- 37% phosphoric acid and pumic or 6% hydrochloric acid and silica
what is macroabrasion
- removal of enamel defect with bur
- 12 fluted carbide or diamond finishing bur, followed by 30 fluted carbide finishing bur
- polished with rubber point
what is the prep guide for porcelain veneers
made from wax to tell you how much reduction is needed to get ideal
where should prep be for optimal bond strength in veneers
in enamel!!!!
what materials are used for minimal prep veneers
- eMAX
- empress
- feldspathic porcelain
what are the reduction criteria for minimal prep veneers
- 0.3mm chamfer at margin or slightly subg
- thickness is 0.5-0.7mm on labial surface
- 1.5mm at incisal reduction
- 1-2mm reduction acceptable
- 90 degree butt joint is best
what are moderate prep veneers
- moderate alignment corrections, up to 3 step change in chroma or value, diastema correction less than 1 mm
what are the reduction criteria for moderate prep veneers
- 0.3mm chamfer at margin or slightly subgingival
- thickness is 0.8-1.0mm on labial surface
- 1.5mm at incisal reduction
- 1-2mm reeuction acceptable
- 90 degree butt joint
what mateirals are used for moderate prep veneers
- emax
- empress
- feldspathic layered porcelain
where does the gingival tooth prep end
at the gingival crest or 0.3-0.5mm subgingival
when severely discolored enamel how much reduction may be required at gingival margin
0.5mm
how much gingival reduction is necessary when the tooth is in linguoversion
none
contour the ____ amount necessary according to the material that you are using to restore the teeth
minimum
what is the summary of incisal margins
- minimum 1-2mm reduction
- no reduction of incisal if lengthening incisal edge
- rounded at all line angles
- butt shoulder on incisal
- no undercut between lingual and gingival
why is there no lingual margin
- seating issues
- lingual margin failure from inadequate porcelain thickness
- porcelain needs bulk when loaded
- incisal butt margin preferred
what should you provisionalize with
a temporary material such as dentsply
what do you use to fabricate provisionals
wax up
how do you insert veneer
- remove provisional and clean prep with nonfluoridated pumice
- clean interproximally lightly with finishing strip
- isolate with rubber dam and sometimes retraction cord
- etch teeth with 37% phosphoric acid in enamel for 30 seconds and dentin for 15 seconds
- place bonding agent
- place light cured composite cement in veneer and place veneer on tooth
- tack cure to clean cement from margin
- remove excess cement
- light cure full amount of time from buccal and lingual
- polish and check occlusion
why should you only use light cure for veneer insertion
- working time
- no color shift
how do you fix occlusion
diamond bur and water spray
why do you not want to overheat veneers when polishing
excess heat may cause degradation of cement bond
what are the common mistakes with veneers
- failure to address gingival asymmetry
- failure to do a wax up for the case
-failure to work with an experienced esthetic ceramist - using ferric sulfate hemostatic agent to stop bleeding around gingiva
- improper bonding technique
- failure to communicate effectively with patient
- starting a case that should have never been started
why dont you use hemostatic agent
it will stain margins- use aluminum chloride- hemodent instead
what can improper bonding technique lead to
microleakage and bacterial growth under restoration
- black staining
