This presentation is about the onlays indications , Types, Steps in preparation etc

1. By:
Dr. R. Seshan Rakkesh B.D.S

2. • Introduction
• Defenition
• Types
• Metal
• Esthetic
• Advantages
• Disadvantages
• Method of fabrication

3. •When decay or fracture
incorporate areas of a tooth that
make amalgam or composite
restorations inadequate, such as
cuspal fracture or remaining
tooth structure that undermines
perimeter walls of a tooth, an
onlay might be indicated.

4. •It is the type of restoration
which caps all the cusps of a
posterior tooth,can be
thoughtfully designed to
strengthena tooth that has
been weakened by caries or
previous restorative
experiences.

5. •The onlay restoration is of
two types,
•Cast metal onlay restorations.
•Esthetic onlay reastorations.

7. • Eliminates the fracture of tooth as in
cast inlay.
• More conservative than a full crown
restoration.

8. • Cuspal protection for all cusps is needed.
• Lenght : Width ratio is 2 : 1
• Need to cahange the occlusal relationship of the
maxillary and mandibula teeth.
• For abutment teeth in partial dentures.
• When excessive tooth wear of occlusal surfaces include
cuspal tips.

9. • Dovetailed internally
• Follow cuspal anatomy anatomy externally.
• Proximally – Box shaped or cone shaped.
• Shoeing of the non – functional cusp.

10. • OCCLUSO – FACIO – LINGUAL PORTION :
• Capped Cusp side :
• Margins located far gingivally.
• Involve 1/3rd or 1/4th of the facial or lingual walls.
• Gingivally :
• Include all the facial and lingual grooves
• Margins parallel to the cusp tips and crest of the adjacent
ridges.
• Shoed Side :
• Margins located just gingival to the tip and ridge crests of the
involved cusps.
• Away from occlusal contact.

12. • Greater occlusal reduction for more bulk
• All circumferential tie constituents must be hollow ground.
• All cusps must be capped rather than shoed.
• Due to possibility of shortening the cavity walls maximum
parallelism should be strived for.
• Preparation should not feature any small, complicated
internal or external details.
• Concavity of hollow ground bevels must include enamel
and dentin.

14. • Cuspal capping rather than shoeing.
• Counter bevel must extend more gingivally to provide
retention.
• Embracing angle for counter bevel must be more acute.
• There is more occlusal reduction for the table and
counter bevel to accommodate more bulk of cast ceramic
(1.5 – 2 mm).
• The gingival, buccal and lingual walls , proximally should
be similar to those for inlay cast ceramics.
• Preparation must be deeper.
• No taper for walls, only parallelism must be achieved.

15. Indicating the
Concavity

16. • Preparation walls should be 6-10° occlusally divergent.
• Cuspal reduction of 1.5-2 mm in functional cusp and 1-
1.5 mm on non-functional cusp.
• All line angles and bevels are smoothly joined with no
interruption.
• Gingival, occlusal bevels and flares are prepared in a
manner such that a marginal cast gold metal of 40° is
obtained.

18. • The various other esthetic restorations for class I
and class II tooth preparations are
• Indirect Composite Inlay and Onlay
• Ceramic Inlay and Onlay
• CAD / CAM or CAD / CIM
(Computer Aided Designing/
Computer Aided Machining)

19. • Esthetic Restorative Systems :
• Direct Composites
• Indirect Systems
• Composite Inlays & Onlays
• Ceramimc Inlays &Onlays
• Direct Systems
• Composite Inlays & Onlays

20. • Same as in cast restoration without bevel / flares.
• Occlusal reduction be 2mm and axial reduction
be 1.5mm
• All internal line angles are rounded to prevent
stress formation.
• Occlusal divergence of 10°.
• Occlusal step depth 1.5 - 2mm
• Pulpal floor Flat & Smooth.

21. • The preparation is etched for 15 - 20
secs then dried.
• Bonding agent applied and cured for 30
secs.
• Then Silane Applied cderamic restorations
or air abraided composite restoration is
applied with dual cure resin luting cement
and placed in preparation. excess is
removed and cured.
• Self etchind dual cure resins are available
e.g. Rely X(3M ESPE).

23. • Direct composite for small – medium cavities.
• Restoration involving the cusp best done by indirect
composite.
• Single/limited teeth with wider restorations best done with
semi direct composite.
• If several teeth are to be restored best done with indirect
composites.
• If a amalgam restored teeth then go for direct composite.

26. • A water soluble separating medium & matrix
band is placed on tooth after preparation.
• Then it is filled by composite cements and light
cured.
• The restoration is teased out of the preparation
so all undercuts in preparation must be remove
for easy removal.
• The restoration is light cured extraorally
(Secondary polymerization)
• Then finished and polished extraorally.
• Finally Luted onto the tooth.

27. • Mainly for one or two surface cavity restorations.
• Sufficient taper of minimum 15°.
• Walls smooth with interlocking.
• Proper separating medium to be used.

29. • In direct/ indirect procedure the impression is made of the
prepared tooth and master cast is fabricated.
• Direct hybrid resin is used to build-up the restoration in
cast, and light cured and additional secondary
polymerization is done.
• Finishing and polishing is done last.
• Tooth Preparation:
• Same as direct resin onlay
• Shallow undercuts need not be worried of.

31. • Available through commercial labs.
• Fabricated on the die.
• Either microfilled / Hybrid composites.
• New generation polymers like ceromers or ceramic
optimised polymers can be used.
• Ceromers – ArtGlass( Heraeus Kulzer ), Targis( Ivoclar
Vivadent)
• Polymerized in specialized unit to achieve a high degree of
polymerization.

32. • Same as in cast restoration.
• Tapered carbied bur/diamond bur used.
• A rougher preparation aids in bonding of the final
restoration.

33. • Open contact and improper proximal contact avoided.
• Marginal leakage dose not occur as polymerization done
extra orally.
• Superior physical properties as done extra orally.
• Increased cost and time factor.
• Requires adequate laboratory skill for fabricating these.

34. • Esthetic requirement of the patient.
• Large cavities.
• Teeth with large restorations.
• Heavy or abnormal occlusal forces.
• Inability to obtain moisture free environment.
• Deep subgingival preparations.

35. • Initially formed on the die.
• Initially light cured for 1min with LED curing unit.
• Secondary polymerization by placing restoration in the
curing oven.( exposing the restoration to additional light
and heat for 7 mins.
• Removed and cooled.
• Finishing and polishing done.

37. • Modern generation ceramic restoration where introduced
in 1983 by Horn JR.
• Ceramic materials employed for ceramic inlays and
onlays are all ceramic materials, these include:
Aluminous porcelain e.g Hi-ceram.
Glass ceramics e.g DICOR(Dentsply)
Pressable glass ceramics, e.g IPS Empress, IPS Empress 2
(Ivoclar-Vivadent)
Slip casting ceramics, e.g In-Ceram.
CAD/CAM ceramics, e.g Procera, Cerec.

38. • Esthetic requirement of the patient.
• Large cavities.
• Teeth with large restorations.
• Heavy or abnormal occlusal forces.
• Inability to obtain moisture free environment.
• Deep subgingival preparations.

39. • Adhesion of resin luting cement to ceramics is far better
than to composite.
• It has long term occlusal stability.
• Better physical properties.
• Better shade matching capability.
• Repair of fractured ceramic restoration is difficult.
• Time consuming laboratory process and difinite two
appointment treatment procedure.
• Expensive restoration.

40. • Preparation walls should be 6-10° occlusally divergent.
• Cuspal reduction of 1.5-2 mm in functional cusp and 1-
1.5 mm on non-functional cusp.
• All line angles and bevels are smoothly joined with no
interruption.
• Gingival, occlusal bevels and flares are prepared in a
manner such that a marginal cast gold metal of 40° is
obtained.
• A carbide bur or diamond bur is used to create a rougher
preparation to aid in bonding of the final restoration.

41. • It involves impression taking either with rubber based
material or alginate.
• Ceramic restoration is fabricated using any one of
following techniques:
 Firing
Pressing
Casting
Machining.
• The finished and glazed ceramic inlay/onlay is etched
with hydrofluoric acid and luted onto preparation using
dual cure resin cements.

43. • CEREC (Ceramic reconstruction system)
1980.
• CELAY System.
• Resin wax pattern fabricated and external
surface of pattern traced mechanically with a
probe and diamentions are given to the
computer to fabricate final ceramic
restoration.

45. • Time saving procedure.
• High quality.
• High esthetics.
• High strength.
• Minimum voids in restoration.
• Marginal gap of about 52 micron(min 25 micron) is
present.
• Minimum staining can be applied externally.
• Costly procedure.
• Special gadget like optical scanner.

46. • Consist of,
• Intraoral camera,
• Video monitor,
• Computer,
• Milling chamber.
• Process,
• Scan tooth preparation.
• Feed data.
• Computer analyses the preparation.
• Restoration is desiged.
• Milling unit cuts the design from a ceramic block.

48. • TOOTH PREPARATION:
• Similar to conventional indirect ceramic onlay
restoration.
• Occlusal aspect reduced to 2mm for clearance.
• All cavosurface margins are prepared to butt
joint(90˚).
• Bevels and chamfers are avoided.

50. • A dry field for proper scanning with precision.
• Tooth preparation is scanned using intra oral camera –
optical impression.
• Tooth surface coated with reflective medium for better
scanning.
• Software designs the restoration, transferred to milling
unit.
• Milling unit has a diamond disk and cylindrical diamond to
cut the ceramic block.
• Removed from milling unit.
• Ceramic restoration is etched and silanated.
• Luted using dual cure resin cement.