By:

Dr. R. Seshan Rakkesh B.D.S

• Introduction

• Defenition

• Types• Metal

• Esthetic

• Advantages

• Disadvantages

• Method of fabrication

• 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.

•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.

•The onlay restoration is of two types,

• Cast metal onlay restorations.• Esthetic onlay reastorations.

• Eliminates the fracture of tooth as in

cast inlay.

• More conservative than a full crown

restoration.

• 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.

• Dovetailed internally

• Follow cuspal anatomy anatomy externally.

• Proximally – Box shaped or cone shaped.

• Shoeing of the non – functional cusp.

• 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.

• 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.

• 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.

Indicating the

Concavity

• 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.

• 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)

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

•Direct Systems• Composite Inlays & Onlays

• 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.

• 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).

• 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.

• 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.

• Mainly for one or two surface cavity restorations.

• Sufficient taper of minimum 15°.• Walls smooth with interlocking.• Proper separating medium to be used.

• 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.

• 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.

• Same as in cast restoration.

• Tapered carbied bur/diamond bur used.

• A rougher preparation aids in bonding of the final

restoration.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.