Ceramic inlays and onlays

CERAMIC INLAYS
AND ONLAYS
Presented by :
Neha Deshpande

CONTENTS
• Introduction
• History
• Indications and contraindications
• Advantages and Disadvantages
• Clinical procedures : INLAYS AND
ONLAYS
• Difference between ceramic and cast
metal inlays and onlays
• Impression
• Try-in and cementation
• Finishing and polishing
• Inlays onlays using Different
ceramic systems
• Common problems and
solutions
• Repair of ceramic inlays and
onlays
• Conclusion

INTRODUCTION
• Dental ceramics are nonmetallic, inorganic structures, primarily containing
compounds of oxygen with one or more metallic or semi-metallic elements
(aluminum, boron, calcium, cerium, lithium, magnesium, phosphorus,
potassium, silicon, sodium, titanium, and zirconium).
• Ceramic inlays offer an aesthetic alternative to metal class I or II
restorations. Their primary use is in compromised posterior teeth with intact
buccal and lingual walls. These restorations offer the opportunity to conserve
tooth structure while taking advantage of the mechanical benefits of modern
adhesive technology, which can strengthen the compromised tooth
• According to Sturdevant, an onlay caps all cusps; an inlay may cap none or
may cap all but one cusp.

HISTORY
• Late 1700s : Ceramic materials were first used in dentistry to fabricate
porcelain denture teeth
• 1887 : Charles H Land, a dentist from Detroit, MI, USA, fabricated the first
ceramic crown
• Early 1970s : Duret pioneered the use of computer-aided
design/manufacturing (CAD/CAM) in dentistry.
• 1980s : Mörmann et al developed the first chair-side economical restoration
of aesthetic ceramics (CEREC) system, which allowed inlays to be
machined from prefired ceramic blocks in the dental office.
• 1980s : the concept of acidetching porcelain to permit use of resin
composite for luting porcelain restorations was developed. At about the
same time, castable glass ceramics were introduced

1. SMALL TO MODERATE CARIOUS
LESIONS
Garber DA, Goldstein RE. Porcelain & composite inlays & onlays: esthetic posterior restorations.
Chicago: Quintessence; 1994 Jan.

2. LARGE CARIOUS OR
TRAUMATIC LESIONS

3. ENDODONTICALLY
COMPROMISED TEETH

4. TEETH WHERE IT IS DIFFICULT TO
DEVELOP RETENTION FORM

5. When metal allergy is a factor
6. The restoration of teeth in an arch opposed by already present
porcelain restorations

CONTRAINDICATIONS
• Parafunctional habits
• Aggressive wear of dentition
• Although technique-sensitivity is itself not a contraindication,
difficulty to maintain a dry operative field and obtaining precisely
fabricated restorations, with attention to detail in placement, can
make this contraindication a reality.

ADVANTAGES
• Improved physical properties
• Variety of materials and techniques
• Wear resistance
• Reduced polymerization shrinkage
• Support of remaining tooth structure
• More precise control of contours and contacts
• Biocompatibility and good tissue response
• Increased auxiliary support
Heymann HO, Swift Jr EJ, Ritter AV. Sturdevant's Art & Science of Operative Dentistry-E-Book. Elsevier Health Sciences; 2014 Mar 12.

DISADVANTAGES
• Increased cost and time
• Technique sensitivity
• Difficult try-in and delivery
• Brittleness of ceramics
• Wear of opposing dentition and restorations
• Short clinical track record
• Low potential for repair

As a first clinical step, the patient is
anesthetized and the area isolated,
preferably using rubber dam.
The compromised restoration (if present)
is completely removed, and all caries is
excavated.
If necessary the walls are restored to a
more nearly ideal form with a light-cured
glass-ionomer liner/base or a composite
restorative material
Occlusal step should be prepared 1.5 to 2
mm in depth.

The carbide bur or diamond used for tooth preparation
should be a tapered instrument that creates occlusally
divergent facial and lingual walls
Isthmus be at least 2 mm wide to decrease the
possibility of fracture of the restoration.
Ideally, there should be no undercuts that would
prevent the insertion or removal of the restoration.Small
undercuts, if present, can be blocked out using a glass-
ionomer liner
Facial and lingual walls should be extended to sound
tooth structure and should go around the cusps in
smooth curves.
The facial, lingual, and gingival margins of the proximal
boxes should be extended to clear the adjacent tooth by
at least 0.5 mm.

TOOTH PREPARATION
• The principles of cavity preparation for esthetic inlays or onlays differ
from those for gold restorations.
• For esthetic inlay or onlay restorations, bevels and retention forms are
not needed.
• Resistance form is generally not necessary but may be required in
very large onlay restorations.
• Retention form is not as critical due to the bonded nature of the
restoration, and bevels are contraindicated.
Freedman GA. Contemporary Esthetic Dentistry-E-Book. Elsevier Health Sciences; 2011 Dec 15.
Hopp CD, Land MF. Considerations for ceramic inlays in posterior teeth: a review. Clinical, cosmetic
and investigational dentistry. 2013;5:21.

Thompson MC, Thompson KM, Swain M. The all‐ceramic, inlay supported fixed partial denture. Part 1.
Ceramic inlay preparation design: a literature review. Australian dental journal. 2010 Jun 1;55(2):120-7.

Freedman GA. Contemporary Esthetic Dentistry-E-Book. Elsevier Health Sciences; 2011 Dec 15.

Garber DA, Goldstein RE. Porcelain & composite
inlays & onlays: esthetic posterior restorations.

RULE FOR CUSP CAPPING

• If cusps must be capped, they should be reduced 1.5 to 2 mm and
should have a 90-degree cavosurface angle.
• When capping cusps, especially centric holding cusps, it may be
necessary to prepare a shoulder to move the facial or lingual
cavosurface margin away from any possible contact with the opposing
tooth, either in maximum intercuspal position or during functional
movements.
• Such contacts directly on margins can lead to premature deterioration
of marginal integrity.
• The axial wall of the resulting shoulder should be sufficiently deep to
allow for adequate thickness of the restorative material and should
have the same path of draw as the main portion of the preparation

• For onlay restorations, nonworking and working cusps are covered with
at least 1.5 mm and 2 mm of material, respectively.
• If the cusp to be onlayed shows in the patient’s smile, a more esthetic
blended margin is achieved by a further 1- to 2-mm reduction with a 1-
mm chamfer

CERAMIC INLAYS
AND ONLAYS
• More bulk needed ,
more clearance
• Bevels
contraindicated
• 6 to 7 degrees of
occlusal divergence
CAST METAL INLAYS
AND ONLAYS
• Less bulk needed
• Bevels necessary
CERAMIC INLAYS AND
ONLAYS
CAST METAL INLAYS
AND ONLAYS
THICKNESS/BULK More bulk needed , more
clearance
Less bulk needed
OCCLUSAL BEVELS Bevels contraindicated Bevels necessary
GINGIVAL BEVELS Not necessary Needed to achieve
minimal marginal gap
CERVICO-OCCLUSAL
DIVERGENCE
6 to 7 degrees of occlusal
divergence
2 to 5 degrees per wall
MARGINAL
ADAPTATION
Rely on adhesion
between tooth
structure/resin
cement/porcelain to
create a gap-free
Rely on close adaptation
(20um);lack of adhesion
between tooth
structure/cement/metal
interface : gingival bevels
are thus needed

CERAMIC INLAYS AND
ONLAYS
CAST METAL INLAYS
AND ONLAYS
PULPAL FLOOR Need not be flat and
perpendicular to the long
axis of the tooth; If the
cavity is shallow ,pulpal
floor should be indented in
central fossa region
parallel to the cuspal
inclines.
Flat and perpendicular to
the long axis of the tooth
INTERNAL LINE ANGLES Rounded internal line and
point angles
Well-defined internal line
and point angles
CAVOSURFACE ANGLE 90 Degrees butt joint 140 to 150 degrees( 30 to
40 degree marginal metal)
CUSP REDUCTION Functional cusp: 1.5mm-
2mm
Non-functional cusp : 1.5
mm
Functional cusp: 1mm-1.5
mm
Non-functional cusp : 1mm

IMPRESSION
• Tooth-colored inlay or onlay systems require an
elastomeric or optical impression of the prepared
tooth and the adjacent teeth and interocclusal records,
which allow the restoration to be fabricated on a
working cast in the laboratory.
• With chairside CAD/CAM systems, no working cast is
necessary.

PROVISIONAL RESTORATION
• For exceptionally nonretentive preparations, or when
the temporary phase is expected to last longer than 2
to 3 weeks, zinc phosphate or polycarboxylate cement
can be used to increase retention of the provisional
restoration.
• Resin-based temporary cements are also available
(e.g., TempBond Clear, Kerr Corporation, Orange, CA)

TRY-IN AND CEMENTATION
• Try-in and bonding of tooth-coloured inlays or onlays are
more demanding than those for cast gold restorations
because of (1) the relatively fragile nature of some ceramic
materials, (2) the requirement of near-perfect moisture
control, and (3) the use of resin cements.
• Occlusal evaluation and adjustment generally are delayed
until after the restoration is bonded, to avoid fracture of the
ceramic material

PRELIMINARY STEPS
• The use of a rubber dam is strongly recommended to
prevent moisture contamination of the conditioned
tooth or restoration surfaces during cementation and
to improve access and visibility during delivery of the
restoration.
• After removing the provisional restoration, all of the
temporary cement is cleaned from the preparation
walls.

RESTORATION TRY-IN AND
PROXIMAL CONTACT ADJUSTMENT
• Passing thin dental floss through the contact reveals tightness and
position of the proximal contact, signifying to the experienced
operator the degree and location of excess contact.
• Articulating paper also can be used successfully to identify overly
tight proximal contacts.
• Abrasive disks or points are used to adjust the proximal contour and
contact relationship.
• While adjusting the intensity and location of the proximal contacts,
increasingly finer grits of abrasive instruments are used to polish the
proximal surfaces because they will be inaccessible for polishing
after cementation.

• Marginal fit is verified after the restoration is completely seated.
• Ceramic inlays and onlays typically have slightly larger marginal
gaps than comparable gold restorations.
• Slight excesses of contour can be removed, if access allows,
using fine-grit diamond instruments or 30-fluted carbide finishing
burs. These adjustments are done preferably after the restoration
is bonded so that marginal fractures are avoided.

MECHANISM OF BONDING
• Bonding of ceramic CAD/CAM restorations is a critical step in
achieving good long-term results.
• Ceramic restorations are bonded to tooth structure by
(1) Etching enamel to increase the bondable surface area
(2) Etching, priming, and applying the bonding agent to dentin
(when appropriate)
(3) Etching (by hydrofluoric acid) and then priming (silanating)
the restoration
(4) cementing the restoration with composite cement

• Ceramic restorations (with the exception of aluminous-core
porcelains, such as In-Ceram High Strength Ceramic [Vita
Zahnfabrik/Vident, Bäd Säckingen, Germany] and zirconia-core
porcelain such as Lava [3M ESPE, St. Paul, Minn]) must be etched
internally with 6% to 10% hydrofluoric acid for 1 to 2 minutes to
create retentive microporosities analogous to those that occur in
enamel on etching with phosphoric acid.
• Hydrofluoric acid must be rinsed off carefully with running water for at
least 2 minutes.
• Sandblasting with aluminum oxide particle can be done in the internal
surface of the restoration.
• Mean bond strengths decrease, however, when hydrofluoric acid
etching is not used.

• The bonding of traditional glass-containing ceramics or silica based
ceramics utilizes mechanical and adhesive way
• Mechanical bonding assumed micromechanical interlocking between the
resin cement and roughen surface of silica-based ceramics.
• Phosphoric acid or hydrofluoric acid etching is the method commonly
used for roughening the silica-based ceramics surfaces
• Chemical adhesion of glass ceramic and resin cements is achieved with
use of bi-functional compounds, silanes that promote connection between
dissimilar organic and inorganic counterparts.
• Also, silanes could influence increasing surface energy and wettabiliy of
ceramic surfaces, which enhances both mechanical and chemical bonding
Obradović-Đuričić K, Medić V, Dodić S, Gavrilov D, Antonijević Đ, Zrilić M. Dilemmas in zirconia bonding: A
review. Srpski arhiv za celokupno lekarstvo. 2013;141(5-6):395-401.

SURFAC
E
PREPAR
A-TION
Grinding
Abrasion with
diamond rotary
instruments
Airborne particle
abrasion with
aluminum oxide
Acid etching
with hydrofluoric
acid or
phosphoric acid
or ammonium
bifluoride
Blatz MB, Sadan A, Kern M. Resin-ceramic bonding: a review of the literature. Journal of Prosthetic
Dentistry. 2003 Mar 1;89(3):268-74.

ACID ETCHING
• Acid etching with solutions of hydrofluoric acid (HF)
or ammonium bifluoride can achieve proper surface
texture and roughness.
• The glassy matrix is selectively removed, and
crystalline structures are exposed.
• HF solutions between 2.5% and 10% applied for 2 to
3 minutes seem to be most successful
Blatz MB, Sadan A, Kern M. Resin-ceramic bonding: a review of the literature. Journal of Prosthetic
Dentistry. 2003 Mar 1;89(3):268-74.

• The well known methods of mechanical and chemical bonding
used on glass-ceramics are not applicable for use with zirconia.
• The most important reason for this is the absence of silica in
the zirconia microstructure which ignores the viability of etching
as a roughening method essential for mechanical bonding, as
well as nullified the use of silanes, forming surfaces hydroxyls
and developing the chemical bond

DIFFERENT APPROCHES IN
ZIRCONIA/CEMENT BONDING
• Surface abrasion or roughening
• Application of a tribochemical silica coating
• Silica coating techniques
Chloro-silane treatment
Selective infiltration etching (SIE)
Nanostructured alumina coating
• Surface treatments: Hot chemical etching solution, Laser application,
Zirconia ceramic powder coating, Application of phosphate ester primers
and phosphate modified resin cements, Gas-phase fluorination process

APPLICATION OF A TRIBOCHEMICAL
SILICA COATING
• This is a technique which uses alumina particles modified with silica for air
abrasion at 0.28 MPa and embedding silica particles in the ceramic
surface.
• Silica particles create a base for micromechanical bonding and interlocking
in ceramic.
• The next step is application of a silane which enables chemical adhesion
between ceramic and resin cement.
• Ex. silica–coated 30 µm aluminum oxide particles, commercial product:
Cojet, Rocatec 3M ESPE

• For intraoral silica-coating applications, the following
can be mentioned: CoJet and Rocatector , Dento-
Prep, and Microetcher
Matinlinna JP, Vallittu PK. Bonding of resin composites to etchable ceramic
surfaces–an insight review of the chemical aspects on surface conditioning.
Journal of oral rehabilitation. 2007 Aug 1;34(8):622-30.

SILICA COATING TECHNIQUES
• Chloro-silane treatment
• Actually, chloro-silane combined with vapor phase technique allowed
pretreatment that deposits a silica-like layer on the zirconia substrate.
• The result is very thin coating (till 2.6 nm) which increased the number of
chemical binding sites (Si x Oy ) for the subsequent organ-saline primer, used
in conventional adhesive technique.
• Application of the chloro-silane film increases the bond strength to resin
cements enabling the values of microtensile bond strength similar to clinically
common bonding technique.

SELECTIVE INFILTRATION
ETCHING (SIE)
• SIE is based on inter-grain metastable tetragonal grains, created during
thermal pre-stressing of the surface grains using a specific thermal
regime. Due to this procedure, the bonding zirconia surface is ready to
accept the adhesive resin which infiltrates and „interlocks“ the bond
• SIE transforms dense, nano-retentive, relatively smooth and low energy
surface of zirconia to highly active and well bonding surface
• In SIE method the surface of zirconia is coated with a glass-containing
conditioning agent silica (65% wt), alumina (15% wt), sodium oxide
(10% wt), potassium oxide (5% wt) and titanium oxide (5% wt) with
closely-matched thermal expansion coefficient to zirconia.

• Later on, the material is heated above glass transition temperature, until
the optimal grain boundary diffusion is achieved.
• After cooling to room temperature, the glass is dissolved in an acidic
bath to eliminate all traces of conditioning agent.
• The cooling and heating rates are controlled by a computer-calibrated
induction furnace
• The resultant effect is of a sealed interface of modified zirconia surface,
which is capable to resist the nano-leakage during artificial aging.

NANOSTRUCTURED ALUMINA COATING
• Nanostructured alumina coating is presented as a new approach which is able to
provide a strong and durable resin bond to Y-TZP.
• It is based on the idea of a rapid precipitation of aluminium hydroxides that originate
from the hydrolysis of AlN (aluminium nitride) powder in a diluted aqueous
suspension.
• The result is heterogeneous nucleation of lamellar boehmite (γAlOOH) onto the
surface of the immersed Y-TZP substrate.
• The nanostructured coatings consist of 6 nm thick and 240 nm long interconnected
polycrystalline γAlOOH lamellas that grow perpendicular to the zirconia surface.
• During a heat treatment up to 900°C, these coatings are transformed into transient
alumina, but without any change in the morphology.
• This non-invasive process can be classified as chemical pretreatment method that
increases the surface area and penetrates the lamellar network, implying good wetting

NANOSTRUCTURED ALUMINA
COATING
• ADVANTAGES :
• It does not create any flaws that can decrease the strength of
zirconia ceramics.
• Functionalization of zirconia surface is more effective compared
to air abraded and polished surface, even after thermo cycling
procedures.
• Technique is simple and can be easily transferred to dental
laboratories

APPLICATION OF PHOSPHATE ESTER
PRIMERS AND PHOSPHATE MODIFIED RESIN
CEMENTS
• This is promising and chair-side method to create a relatively stable bond
zirconia/tooth structure, but alone insufficient to stand long-term intraoral
conditions
• The adhesive functional monomers are believed to have the ability to form
chemical hydrogen bonds with metal oxides at the resin/zirconia interface,
improving the wettability.
• On the other hand, the composition of resin cement, for example, large filler
size and high viscosity could affect the wettability significantly.
• The most frequent phosphate monomer groups used in resin cement or metal
primers are the following: 10-methacryloyl oxydecyl dihydrogen phosphate,
MDP (the adhesive monomer in Panavia F 2.0, Alloy Primer, Clearfil SE
Bond/Porcelain Bond activator, Clearfil Ceramic primer), methacrylated
phosphoric ester (adhesive monomer in RelyX Unicem), and phosphoric acid
acrylate (the adhesive monomer of multilink automix)

• The purpose of this study was to assess the surface topography of
6 different ceramics after treatment with either hydrofluoric acid
etching or airborne aluminum oxide particle abrasion.
• Five copings each of IPS Empress, IPS Empress 2 (0.8 mm thick),
Cergogold (0.7 mm thick), In-Ceram Alumina, In-Ceram Zirconia,
and Procera (0.8 mm thick) were fabricated following the
manufacturer’s instructions.
• Each coping was longitudinally sectioned into 4 equal parts by a
diamond disk.
Borges GA, Sophr AM, De Goes MF, Sobrinho LC, Chan DC. Effect of etching and airborne particle abrasion
on the microstructure of different dental ceramics. Journal of Prosthetic Dentistry. 2003 May 1;89(5):479-88.

• The resulting sections were then randomly divided into 3 groups depending
on subsequent surface treatments: Group 1, specimens without additional
surface treatments, as received from the laboratory (control); Group 2,
specimens treated by use of airborne particle abrasion with 50-µm
aluminum oxide for 5 seconds at 4-bar pressure; and Group 3, specimens
treated with 10% hydrofluoric acid etching (20 seconds for IPS Empress 2;
60 seconds for IPS Empress and Cergogold; and 2 minutes for In-Ceram
Alumina, In-Ceram Zirconia, and Procera)
• Airborne particle abrasion changed the morphologic surface of IPS
Empress, IPS Empress 2, and Cergogold ceramics.
• The surface topography of these ceramics exhibited shallow irregularities
not evident in the control group.

• For Procera, the 50-m aluminum oxide airborne particle abrasion produced a
flattened surface. Airborne particle abrasion of In-Ceram Alumina and In-
Ceram Zirconia did not change the morphologic characteristics and the same
shallows pits found in the control group remained.
• For IPS Empress 2, 10% hydrofluoric acid etching produced elongated
crystals scattered with shallow irregularities. For IPS Empress and
Cergogold, the morphologic characteristic was honeycomb-like on the
ceramic surface.
• The surface treatment of In-Ceram Alumina, In-Ceram Zirconia, and Procera
did not change their superficial structure.
• They concluded that hydrofluoric acid etching and airborne particle abrasion
with 50-m aluminum oxide increased the irregularities on the surface of IPS
Empress, IPS Empress 2, and Cergogold ceramics. Similar treatment of In-
Ceram Alumina, In-Ceram Zirconia, and Procera did not change their
morphologic microstructure.

• The purpose of this study was to compare the dentin bond strengths of 2
different ceramic inlay systems after cementation with 3 different
techniques and 1 bonding system
• One hundred twenty freshly extracted caries- and restoration-free molar
teeth used in this study were stored in saline solution at room
temperature. Standardized Class I preparations were made in all teeth.
• Each preparation had a length of 6 mm, a width of 3 mm, a depth of 2
mm, and 6-degree convergence of the walls. Teeth were randomly
assigned to 2 groups of 60 each to evaluate the bonding of 2 ceramic
systems, Ceramco II (Group I) and IPS Empress 2 (Group II), to dentin.
• Each of the 2 groups were further divided into 3 cementation technique
groups of 20 each (Group I A, B, and C and Group II A, B, and C).
Ozturk N, Aykent F. Dentin bond strengths of two ceramic inlay systems after cementation with three
different techniques and one bonding system. Journal of Prosthetic Dentistry. 2003 Mar 1;89(3):275-81.

• Groups I A and B and Groups II A and B used dentin bonding agent (DBA)
Clearfil Liner Bond 2V, and resin cement (Panavia F). Groups I C and II C
served as control groups and used Panavia F without the dentin-bonding
agent. In Groups I A and II A, the DBA was applied immediately after the
completion of the preparations (D-DBA).
• Impressions were then made, and the ceramic inlays were fabricated
according to the manufacturers’ guidelines. In Groups I B and II B the DBA
was applied just before luting the inlay restorations (I-DBA). In Groups I C
and II C, no bonding agent was used before the cementation of the inlay
restorations (No DBA).
• Cementation procedures followed a standard protocol. After cementation,
specimens were stored in distilled water at 37° C for 24 hours.

• The teeth were sectioned both mesial-distally and buccal-lingually along their
long axis into three 1.2 1.2 mm wide I-shaped sections. The specimens were
then subjected to microtensile testing at a crosshead speed of 1 mm/min, and the
maximum load at fracture (in kilograms) was recorded. Two-way analysis of
variance and Tukey honestly significant difference tests were used to evaluate
the results
• Scanning electron microscopy analysis was used to examine the details of the
bonding interface. The fractured surfaces were observed with a
stereomicroscope at original magnification to identify the mode of fracture.
• The tensile bond strength in the D-DBA technique (40.27 MPa) was significantly
higher than both the I-DBA (30.20 MPa) and No-DBA techniques (32.43 MPa) for
2 different ceramic systems. Also, fracture surfaces of each specimen examined
under stereomicroscopy demonstrated that 98% of the failures were adhesive in
nature. In SEM examination, a distinct and thicker hybrid zone with longer and
more resin tags were found in the D-DBA technique than in the I-DBA and No-
DBA techniques.

• As a result of scanning electron microscopy analysis, a distinct
and thicker hybrid zone with more, and longer resin tags were
found in specimens treated with the D-DBA technique than with
the other 2 techniques.
• Most failures (353 of 360) were adhesive in nature at the
bonding resin/dentin interface. Only 7 specimens showed
cohesive failure within the bonding resin.
• They concluded that, the cementation of the ceramic inlays
tested with the D-DBA technique used resulted in higher bond
strengths to dentin

• The preparation surfaces are etched and treated with the components of an
appropriate enamel/dentin bonding system
• Typically, the final step of the bonding system (e.g., an unfilled resin) also is
applied to the internal surfaces of the restoration previously etched and
silanated. (Self-adhesive, resin based cements have been introduced in recent
years, but whether they are appropriate with tooth-colored inlays/onlays remains
unproven.)
• A dual-cure composite cement is mixed and inserted into the preparation with a
paddle-shaped instrument or a syringe.
• The internal surfaces of the restoration also are coated with the composite
cement , and the inlay is immediately inserted into the prepared tooth, using light
pressure.
• A ball burnisher applied with a slight vibrating motion is usually sufficient to seat
the restoration
• Excess composite cement is removed with thin-bladed composite instruments,
brushes, or an explorer
CEMENTATION

• This review describes the potential of adhesive luting procedures with respect
to (1) material characteristics and classifications, (2) film thickness, (3)
overhang control, (4) bonding to different inlay materials, (5) adhesion to
tooth substrates and the problem of hypersensitivities, (6) wear of luting
composites, and (7) clinical performance.
• A literature review of relevant studies of various in vitro and in vivo studies
enables an overview of possibilities and limitations of adhesively luted indirect
restorations.
• They concluded that :
(1) Resin-based composites are the material of choice for adhesive luting. Both
material properties and wear behavior of fine particle hybrid-type resin-based
composites are superior to other materials. The use of compomers is
questionable due to hygroscopic expansion and possible crack formation as
proven for IPS Empress caps in vitro and in vivo.
Krämer N, Lohbauer U, Frankenberger R. Adhesive luting of indirect restorations. American Journal of Dentistry. 2000 Nov;13(Spec
No):60D-76D.

(2) Recent luting cements exhibit excellent flow characteristics with mean film
thicknesses ranging between 8 microm and 21 microm. The ultrasonic
insertion technique is recommended for viscous luting composites or
conventional restorative composites utilizing their thixotropic properties.
(3) For successful overhang control, good fit of the restoration (during luting)
and high radiopacity of the cement (after luting) are indispensable.
Overhang control is estimated easier when the ultrasonic insertion
technique is applied.
(4) The pre-treatments of ceramic inlays using hydrofluoric acid or silica
coating result in effective bonding; for pre-treatment of resin-based
composite inlays, silica coating is promising as well.
(5) Bonding to enamel and dentin is proven clinically acceptable, but it should
be performed with multi-step systems providing separate primers and
bonding agents producing a perfect internal seal with almost no
hypersensitivities. Dual-cured multi-step bonding agents provide the most
promising potential.

(6) The viscosity and filler content of the resin composite used for luting
does not influence the wear characteristics within the marginal luting
area in vivo. However, the ultrasonic insertion technique involving high
viscosity materials provides enhanced handling characteristics for
luting of tooth-colored inlays.
(7) Clinical results with tooth-colored inlays and veneers are promising
over periods of up to 10 yrs, including use in severely destroyed teeth.

FINISHING AND POLISHING
PROCEDURES
• After light-curing the cement, the plastic matrix strips and the wedges (if
used) are removed, and the setting of the resin cement is verified.
• All marginal areas are checked with an explorer tine

FELDSPATHIC PORCELAIN INLAYS
AND ONLAYS
After tooth preparation, an impression is made, and a
“master” working cast is poured of die stone
The die is duplicated and poured with a refractory
investment capable of withstanding porcelain-firing
temperatures. The duplication method must result in
the master die and the refractory die being
accurately interchangeable
Porcelain is added into the preparation area of the
refractory die and fired in an oven. Multiple
increments and firings are necessary to compensate
for sintering shrinkage
The ceramic restoration is recovered from the
refractory die, cleaned of all investment, and seated
on the master die and working cast for final
adjustments and finishing

FELDSPATHIC PORCELAIN
INLAYS AND ONLAYS
• Advantages : Low startup cost.
• The ceramic powders and investments are relatively inexpensive, and the
technique is compatible with most existing ceramic laboratory equipment
such as firing furnaces.
• Disadvantages :technique sensitivity, both for the technician and the
dentist.
• Inlays and onlays fabricated with this technique must be handled gently
during try-in and bonding to avoid fracture.
• Feldspathic porcelains are weak, so even after bonding, the incidence of
fracture can be relatively high

PRESSED GLASS-CERAMICS
• In 1984, the glass-ceramic material Dicor (DENTSPLY International,
York, PA) was patented and became a popular ceramic for dental
restorations. A major disadvantage of Dicor was its translucency,
which necessitated external application of all shading
• Dicor restorations were made using a lost-wax, centrifugal casting
process. Newer leucite-reinforced glass-ceramic systems (e.g., IPS
Empress, Ivoclar Vivadent, Amherst, NY) also use the lost-wax
method, but the material is heated to a high temperature and
pneumatically pressed, rather than centrifuged, into a mold

• After tooth preparation, an impression is made, and a working cast
is poured in die-stone. A wax pattern of the restoration is made
using conventional techniques
• After spruing, investing, and wax pattern burnout, a shaded ceramic
ingot and aluminum oxide plunger are placed into a special furnace
• The shade and opacity of the selected ingot are based on the
information provided by the clinician, specifically the desired shade
of the final restoration and the shade of the prepared tooth.
• At approximately 2012°F (1100°C), the ceramic ingot becomes
plastic and is slowly pressed into the mold by an automated
mechanism.

• After being separated from the mold, the restoration is seated on the
master die and working cast for final adjustments and finishing.
• To reproduce the tooth shade accurately, a heavily pigmented
surface stain is typically applied.
• The ceramic ingots are relatively translucent and available in a
variety of shades, so staining for hot pressed ceramic inlay and
onlay restorations is typically minimal.

• The advantages of leucite-reinforced pressed ceramics are their
(1) similarity to traditional “wax-up” processes
(2) excellent marginal fit
(3) moderately high strength
(4) surface hardness similar to that of enamel.
Although pressed ceramic inlays and onlays are stronger than
porcelain inlays made on refractory dies, they are still somewhat
fragile during try-in and must be bonded rather than conventionally
cemented.

LITHIUM DISILICATE
• Lithium disilicate (e.max, Ivoclar Vivadent Inc., Amherst, NY), is
available in both pressed (IPS e.max Press) and machinable (IPS
e.max CAD) forms, and either can be used to fabricate inlays and
onlays.
• The two forms of e.max are slightly different in composition, but
lithium disilicate is a moderately high-strength glass ceramic that also
can be used for full crowns or ultra-thin veneers.
• In vitro testing of this ceramic material has shown very positive
results, and it has become a highly popular alternative for inlays and
onlays.
• However, because the material is relatively new, long-term clinical
studies to demonstrate superior performance are lacking.

COMPUTER-AIDED DESIGN/COMPUTER-
ASSISTED MANUFACTURING INLAYS AND
ONLAYS
• Generation of a chairside CAD/CAM restoration begins after the dentist
prepares the tooth and uses a scanning device to collect information
about the shape of the preparation and its relationship with the
surrounding structures
• This step is termed optical impression.
• The system projects an image of the preparation and surrounding
structures on a monitor, allowing the dentist or the auxiliary personnel to
use the CAD portion of the system to design the restoration.
• The operator must input or confirm some of the restoration design such
as the position of the gingival margins

• After the restoration has been designed, the computer
directs a milling device (CAM portion of the system) that
mills the restoration out of a block of high-quality ceramic
or composite in minutes
• The restoration is removed from the milling device and is
ready for try-in, any needed adjustment, bonding, and
polishing

• Several different types of ceramics are available for chairside CAD/CAM
restoration fabrication.
• These include the feldspathic glass ceramics Vitablocs Mark II (Vident,
Brea, CA) and CEREC Blocs (Sirona, manufactured by Vita Zahnfabrik,
Bad Säckingen, Germany).
• The ceramic blocks are available in various shades and opacities, and
some are even layered to mimic the relative opacity or translucency in
different areas of a tooth.
• Two leucite-reinforced glass ceramics are available—IPS Empress CAD
(Ivoclar Vivadent) and Paradigm C (3M ESPE).
• Lithium disilicate also is available in machinable form as IPS e.max CAD
blocks. Although newer materials are stronger than the original ceramics,
less is known about their long-term clinical performance

CERAMIC RECONSTRUCTION
SYSTEM (CEREC-1)
• The Ceramic Reconstruction System (CEREC-1; Siemens,
Germany) was the first commercially available CAD/CAM system
used in dentistry.
• An intraoral video camera images the tooth preparation and the
adjacent tooth surfaces.
• Elevations of the imaged surfaces are calculated by Moiré fringe
displacement.
• Features of the tooth preparation are used to define the limits of
the restoration.

• External surfaces of the restoration are estimated as distances to
adjacent tooth structure in the computer view.
• Occlusal surfaces are designed from a preexisting shape library
and information about the occlusion.
• CEREC-3 displays an extremely high level of sophistication and
can fabricate inlays, onlays, crowns, and veneers.
• It can be operated chairside, but also is being used with remote
milling units in dental laboratories for two-appointment
procedures.
• All other current CAD/CAM systems are employed in dental
laboratories to fabricate a wide range of ceramic restorations

CEREC AC (A) and
E4D (B) computer-
aided design/
computer-assisted
manufacturing
(CAD/CAM) devices.
These chairside units
are compact and
mobile

Hopp CD, Land MF. Considerations for ceramic inlays in posterior teeth: a review.
Clinical, cosmetic and investigational dentistry. 2013;5:21.

COMMON PROBLEMS AND
SOLUTIONS
• The most common cause of failure of tooth-colored inlays/onlays
is bulk fracture.
• Bulk fracture can result from placing the restoration in a tooth
where it should not have been indicated, such as in bruxers and
clenchers, or from lack of appropriate restoration thickness
derived from lack of tooth preparation.
• If bulk fracture occurs, replacement of the restoration is almost
always indicated.

• Microtensile bond strength (microTBS) evaluation and fractographic analysis
were used to compare four luting systems in the cementation of resin-based
composite (RBC) and ceramic disks to dentin.
• Forty freshly-extracted molars were transversally sectioned to expose flat,
deep dentin surfaces. Forty cylindrical specimens (5-mm diameter and 10-
mm height), consisting of 20 RBC disks and 20 leucite-based glass ceramic
disks, were produced.
• The ceramic disks were conditioned with 9.5% hydrofluoric acid gel and
silane application. All the disks were then bonded to dentin surfaces
according to the luting cements to be used: two etch-and-rinse luting agents
(XP bond/CoreXFlow; Dentsply [XP]) (Enabond/EnaCem HF; Micerium
[ENA]), a self-etch luting system (ED Primer II A+B/Panavia F2.0; Kuraray-
Dental [PAN]) and a self-adhesive luting agent (RelyX Unicem; 3M ESPE
[UNI]).

• The adhesive/luting cement systems were applied according to the
manufacturers' instructions. The specimens were sectioned
perpendicular to the adhesive interface to produce multiple beams,
approximately 1 mm2 in area.
• The beams were tested under tension at a crosshead speed of 0.5
mm/minute until failure. The microTBS data were analyzed by two
different one-way-ANOVA and multiple comparison Tukey tests (alpha =
0.05). All the fractured beams were observed using a Scanning Electron
Microscope (SEM) at 200x magnification for fracture mode
determination
D'arcangelo C, De Angelis F, D'amario M, Zazzeroni S, Ciampoli C, Caputi S. The influence of luting systems on
the microtensile bond strength of dentin to indirect resin-based composite and ceramic restorations. Operative
Dentistry. 2009 May;34(3):328-36.

• Type 1: Cohesive failure in dentin • Type 2: Adhesive failure at the luting-
dentin interface • Type 3: Mixed adhesive failure and cohesive failure in
dentin • Type 4: Cohesive failure in the luting agent • Type 5: Mixed adhesive
failure and cohesive failure in RBC (or ceramic) • Type 6: Adhesive failure at
the luting-RBC (or ceramic) interface
D'arcangelo C, De Angelis F, D'amario M, Zazzeroni S, Ciampoli C, Caputi S. The influence of luting systems on
the microtensile bond strength of dentin to indirect resin-based composite and ceramic restorations. Operative
Dentistry. 2009 May;34(3):328-36.

REPAIR OF CERAMIC INLAYS AND
ONLAYS
• Before initiating any repair procedure, the operator should
determine whether replacement rather than repair is the
appropriate treatment
• A small fracture resulting from occlusal trauma might indicate that
some adjustment of the opposing occlusion is required.
• The repair procedure is initiated by mechanical roughening of the
involved surface. Although a coarse diamond may be used, a
better result is obtained with the use of air abrading or grit
blasting with aluminum oxide particles and a special intraoral
device

• For ceramic restorations, the initial mechanical roughening is followed by
brief (typically 2 minutes) application of 10% hydrofluoric acid gel.
• Hydrofluoric acid etches the surface, creating further microdefects to
facilitate mechanical bonding.
• The next step in the repair procedure is application of a silane coupling
agent.
• Silanes mediate chemical bonding between ceramics and resins and
may improve the predictability of resin-resin.
• After the silane has been applied, a resin adhesive is applied and light
cured.
• A composite of the appropriate shade is placed, cured, contoured, and
polished

• This systematic review and meta-analysis aimed to evaluate the survival rate of
ceramic and resin inlays, onlays, and overlays and to identify the complication
types associated with the main clinical outcomes
• In the present study, the pooled estimated survival rate was 95% for 5 y of
follow-up and the survival rate decreased to 91% after 10 y of follow-up (93%
for glass-ceramics and 91% feldspathic porcelain), yet this was not a significant
difference. One explanation for the similar performance of glass-ceramics and
feldspathic porcelain could be the adhesive cementation that likely
compensated for the mechanical differences between the 2 ceramic materials
• This meta-analysis indicates that the survival rate of inlays, onlays, and
overlays remains high, irrespective of the follow-up time (5 y and 10 y) and
regardless of the ceramic material, study design, and study setting.
• Thier results indicate that fractures remain the most frequent type of failure.
• The type of tooth does not seem to affect survival rates, but restorations
survived longer on vital teeth
Morimoto S, Rebello de Sampaio FB, Braga MM, Sesma N, Özcan M. Survival rate of resin and ceramic
inlays, onlays, and overlays: a systematic review and meta-analysis. Journal of dental research. 2016
Aug;95(9):985-94.

Morimoto S, Rebello de Sampaio FB, Braga MM, Sesma N, Özcan M. Survival rate of resin and ceramic
inlays, onlays, and overlays: a systematic review and meta-analysis. Journal of dental research. 2016
Aug;95(9):985-94.

• The objectives of this study were to: (1) compare the fracture resistance of
metal-ceramic inlays with that of all-ceramic inlays; (2) determine the
correlation between the degree of preparation taper and fracture resistance;
and (3) determine the correlation between marginal gap width and fracture
resistance.
• Inlay preparations were made on 60 Dentoform teeth, with 30 teeth allocated
for metal-ceramic inlays and 30 teeth for all-ceramic inlays.
• Each group was further subdivided into 5-, 10-, and 20-degree taper
preparations.
• Metal-ceramic inlays were fabricated using Goldtech Bio 2000 metal and
Ceramco porcelain extending to the margin, while all-ceramic inlays were
made from Empress II ceramic. Marginal gap widths were measured at six
critical areas after fabrication. The load at failure was measured using an
Instron Universal Testing Machine.
Esquivel-Upshaw JF, Anusavice KJ, Reid M, Yang MC, Lee RB. Fracture resistance of all-ceramic and metal-
ceramic inlays. International Journal of Prosthodontics. 2001 Mar 1;14(2).

• The mean fracture load for all-ceramic inlays and metal-ceramic inlays at
5, 10, and 20 degrees was 70+/-40 N, 48+/-37 N, 33+/-7 N, and 40+/-23 N,
29+/-22 N, and 14+/-4 N, respectively.
• The mean gap width was 105 microm and 126 microm for all-ceramic and
metal-ceramic inlays, respectively.
• They concluded that the mean fracture load for Empress inlays was
significantly higher than that for metal-ceramic inlays.
• Inlays with a 5-degree taper were significantly more fracture resistant than
those with a 20-degree taper.
• There was no relation between marginal gap width and fracture resistance.
Esquivel-Upshaw JF, Anusavice KJ, Reid M, Yang MC, Lee RB. Fracture resistance of all-ceramic and metal-
ceramic inlays. International Journal of Prosthodontics. 2001 Mar 1;14(2).

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