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