ClassIV Final

8/3/2019 ClassIV Final

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CLASS FOUR FROM CAVITY TO SMILE

Success in restoration is a result in success inknowing the cause and the treatment

Composite resins allow clinicians to create restorationswith improvedbiocompatibility, function, and aesthetics. By ensuring thatthe patients condition is clearly and thoroughly evaluatedpreoperatively, the clinician can develop natural,harmonious integration of the restorative material with thepatients natural tooth structures. The critical informationcaptured during the initial visit can also be used to ensuredevelopment of natural contours, light refraction, andcharacterization. This research describes the fundamentals


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Class four etiology andtreatment modalities .Class four from cavity to smile.

Success in restoration is a result in success in

knowing the causes and treatment.

Done by :Abdulla Hassanien

Amira yehia

Heba lotfy


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Content:1. Definition and classification.

2. Etiology.

3. Shade selection.

4. Peroperative consideration as a modern

technique for better esthetic.

5. Traditional cavity preparation and

restoration.

6. Modified class IV preparation restoration.

7. Specific finishing materials.

8. Uses of pins.

9. Case presentation.

10. Restoration of class IV fracture using

nanocomposite.

11. References.

Black Class IV:


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An extension of a Class III lesion involving the incisal corner or incisal edge of an

anterior tooth. An alternative cause would be traumatic fracture of the incisal corner

now classified Site 2, Size 4 Up to the recent time Profession has used a

classification of cavities proposed by G. V. Black over one hundred years ago. The

classification was designed before the widespread use of radiographs so lesions were

not diagnosed until they were visible to the naked eye and were therefore, by

modern standards, relatively large.A further problem was that ,it was a

classification of cavity designs for amalgam as this was the principal restorative

material available. The result was that regardless of the size of the lesion, a specific

cavity design was required to deal with it. Today current knowledge offers many

alternatives ranging from earlier diagnosis of caries activity, along with effective

methods of control, to the application of adhesive and bioactive restorative

materials. If our patients are to reap the full benefit of these advances it is necessary

to review both the classification and the approach to the surgical treatment of lesionswhen they progress beyond remineralization alone classification However, as caries

can be a progressive disease, it is desirable to be able to define the size and extent of

the lesion at the time of identification and, therefore, the potential complexity of the

restorative procedures required for treatment.

It is possible then to define five separate sizes as the lesion progresses:

Size 0The earliest lesion that can be identified as the initial stages of demineralization.

This needs to be recorded but will be treated by eliminating the cause and should

therefore not require further treatment.Size 1Minimal surface cavitation with involvement of dentine just beyond treatment by

remineralization alone. Some form of restoration is required to restore the smooth

surface and prevent further plaque accumulation.

Size 2Moderate involvement of dentine. Following cavity preparation remaining enamel

is sound, well supported by dentine and not likely to fail under normal occlusal load.

The remaining tooth structure is strong enough to support the restoration.

Size 3The lesion is enlarged beyond moderate. Remaining tooth structure is weakened to

the extent that cusps or incisal edges are split, or are likely to fail if left exposed to

occlusal load. The cavity needs to be further enlarged so the restoration can be

designed to support the remain tooth structure.

Size 4Extensive caries or bulk loss of tooth structure e.g. loss of a complete cusp or

incisal edge, has already occurred.


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Etiology :

A caries induced class 4 restoration is the result of a large class 3 caries lesion that

has undermined the incisal edge.The need for class 4 restoration due to traumatic

fracture occurs most often among children or young adults. The frequency of

fractures of permanent incisors in children is reported to range from 5%to

20%.Traumatic fracture are likely to be more horizontal than vertical.


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Shade selection:

Composite shade is selected by working with a clean, moist tooth prior to placement

of a rubber dam. Once teeth are isolated by a rubber dam they dry out and get lighter

in color, making accurate shade selection difficult.

Since the shade guides provided by many manufacturers are not made of composite,

they may not accurately represent a composite shade. Studies show custom guides

made of composite are considerably more accurate than a manufacturers mock-

composite shade guide. Even better accuracy is achieved if the custom shade tabs

are stored in water, but problems with controlling bacterial growth make this

mpractical. Storing in water hydrates the tabs, maintaining conditions similar to

those of the mouth. Hydrated composite shade tabs are darker than dry ones.

Once a shade is chosen for a discolored tooth, verify the masking ability of the

composite by placing material on the tooth in the same thickness as will be used inthe restoration and then curing.

Placing a color modifier on the tooth under the composite can improve its color or

masking ability.

With auto cured systems, if the shade of the tooth does not match one of the shade

guides, different shades can be mixed to obtain a more accurate match. With light-

cured systems, composites can be layered, placing darker materials underneath and

lighter materials over the surface to provide intermediate shades.

Using a master shade guide system:

All restoratives and chair side shade guides should be matched to a master shade

guide. All materials should be tested to match this master, and restoratives should be

relabeled when discrepancies occur.

Before using a new restorative product, polymerize the material and place the

sample in water for 24 hours. After the sample has rested for 24 hours, match its

color to the office master shade guide. Materials are often a shade or more off of the

master guide. For example, shade A3 of a particular product may match the A2

master shade guide, so it should be relabeled A2. Standardizing all office restorative

materials to a single shade stabilizes restoration esthetics, such that once a patientsshade is determined, all calibrated restoratives will match.

A number of shade guide systems are commercially available. By far the most

common is the Vita Lumin system (Vita Zhnfabrik, Bad Sackingen, Germany),

which breaks shades first into hues and then shows hues with increased chroma and

decreased value. Vitas newer Vitapan system breaks shades into value (darkness),

hue, and chroma (color).

Value is the most important characteristic of a shade since it is not light dependent.

Hence, the new Vita system differentiates shades according to their most importantcharacteristics.

The most common shade used in indirect restorations is A2. It is so popular a shade

that using it for full-mouth reconstruction pleases most patients. With older patients,

this shade may appear light but is still preferred by most patients.


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Preoperative Considerations as a modern technique for

better esthetics:

The aesthetic restoration of a single anterior tooth is extremely difficult to perform

using porcelain or composite resin. Shade selection should be accomplished prior torubber dam isolation to prevent improper color matching that may result from

dehydration and elevated values.

When teeth dehydrate, the air replaces the water between the enamel rods, changing

the refractive index that makes the enamel appear opaque and white.

By using a previsualized mockup and knowledge of composite materials, the

surrounding environment, the modifiers selected, and their shade and orientation, the

definitive restoration can be visualized prior to completion. The transformation of

this vision into an aesthetic creation that replicates natural variations constitutes the

clinicians final challenge.

Consideration of the surrounding environment is crucial for optimal color matching

of composite restorations.

Composite resin, enamel, and dentin cause considerable light scattering, which

produces internal diffusion of incident light and allows the composite restoration to

blend with the tooth appearance. This blending effect (or chameleon effect) occurs

as diffused light enters from the surrounding tooth. When this light is emitted from

the restoration it will absorb color from the tooth and alter it. This color alteration

depends on the scattering and absorption coefficients, which can produce an

undetectable color match by blending with tooth color.Once the shade analysis has been completed, the appropriate composite material can

then be selected.

An ideal composite resin should provide color stability, polishability, and

sculptability; it should also endure functional stress and produce optimal aesthetics.

Traditional cavity preparation:

The standard setup and supplies required are listed later on. Specific additionalmaterials needed for Class IV restorations include:

A light-cured submicron or small-particle composite in a tube, or a material that

can be shaped without slumping. In some clinical situations, a heavily filled

composite is used as a core. Some operators prefer to use a microfilled composite as

the final surface material for these restorations.

A bullet-shaped chamfer diamond

Preparations:

Decide on the tooth shade prior to rubber dam placement. Anesthesia is oftenunnecessary for small fractures where the preparation is limited to enamel. Larger

fractures with exposed dentin may be sensitive to air, cold water, and bur vibration

and often require anesthesia. Determine the tooth shade, then place a rubber dam and

clean the tooth with pumice and water.


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Outline:

. These preparations are appropriate for fractures that run one-third to two-thirds of

the incisal edge, which often expose dentin.

Most anterior teeth have horizontal and vertical grooves that can be used to hide the

margins and increase the color-match and esthetic outcome .

Chamfer design:

Prepare a chamfer 1-mm long (or half the length of the fracture) to half the

depth of the enamel on the labial and lingual surface. This type of preparation results

in the most durable restorative margins . It is important that the chamfer is cut only

halfway through the enamel surface.

Horizontal and vertical lines are easily hidden in anatomy, whereas oblique lines

conflict with natural anatomy and surface texture and are, therefore, more visible.Stair-stepping the labial enamel with a good chamfer cavosurface margin into the

tooth anatomy helps achieve a good esthetic result .

Beveled margins:

An alternative to a stair-step chamfer design is to prepare a 2- to 3-mm bevel in

place of a chamfer . This bevel creates a gradual change of color from the tooth to

the restoration. Although the beveled margin is not as durable as a chamfer, beveled

preparations usually provide more consistent esthetic results. Scalloping the labial

enamel with a beveled cavosurface margin is less important in achieving an esthetic

result. It is best to finish these bevels in a curve, going from horizontal to facial .

The major problem encountered at recall with beveled margins is chipping.

Enamel conditioning:

Clean the preparation of all debris. Make sure the enamel cavosurfaces are clean ofany dentin lining materials. After protecting the adjacent teeth with a Mylar strip,

etch with acid using an enamelresin bonding technique. This technique usually

involves a 20-second etch of the enamel and a 10-second (or less) etch of the dentin,

rinsing for a minimum of 5 seconds, then drying according to the manufacturers

recommendation for the specific bonding agent.

Composite placement

Prepare, etch, and dry the tooth; add bonding agent, and cure. Place a Mylar strip.

Place and form the composite in a minimum of three increments, each 1- to 2-mm

thick . For the first layer, the composite core, use a heavily filled material. Form it to

the proper contour with Mylar, an interproximal carver, and an explorer. Remove the

excess material from the gingival and proximal areas with an explorer. Polymerize

for a minimum of 40 seconds on each side. For darker shades, polymerize for 60

seconds on each side (for materials with an EOP of 16 joules.)


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Step 1. Place the composite core, using a heavily fill material. Wedge the composite

between the Mylar strip and tooth fracture.

Step 2. Shape the composite core by slowly pulling the Mylar through to wrap the

composite to the lingual, which draws the composite around the tooth.

Step 3. Polymerize the composite core.

Step 4. Place the contouring layer, using a submicron material.

Step 5. Slowly pull the Mylar strip through to wrap composite to the lingual.

Step 6. Separate the composite from the Mylar strip, and contour. Remove the strip

quickly.

Step 7. Polymerize for a minimum of 40 seconds on each side (60 seconds for

darker shades).

Step 8. Replace the Mylar strip. Add a final layer of composite, and contour. Slowly

pull the Mylar strip through to wrap composite to the lingual. Pull the Mylar strip

through rapidly to separate the strip from the composite. Remove the strip.

Step 9. Remove excess composite and carefully contour.

Step 10. Polymerize for a minimum of 40 seconds on each side (60 seconds for

darker shades).

Step 11. When set, check for voids and excess material. Repair any voids

.

Step 12. Wait 10 minutes after the last addition of composite before contouring the

restoration.

Most composites do not cure thoroughly if built to a thickness greater than 2 mm. If

the thickness of the fracture is in excess of 4 mm across the center of the restoration

(from labial to lingual), the central area will be more than 2 mm from the surface. Inthis situation, multiple placement in place, add and cure a central core of composite

within 2 mm of the final surface of the restoration.

After this addition, a crown form can be used for composite final placement. If a

crown form is not being used, add the composite in layers with a plastic instrument.

Make sure each layer is less than 2 mm thick, and cure after each addition. The final

layer should be contoured and shaped until it closely resembles the desired shape of

the tooth, and then polymerized.

Finishing

Step 1. Remove flash with a sharp hand instrument or a No. 15 Bard Parker blade.

Step 2. Use fine diamonds for gross reduction. Also use a lubricant to reduce heat

and friction.

Step 3. When approaching the margins, use only micron diamonds or flexible discs.

A finishing strip is a good alternative at the proximal margins.

Step 4. When using a microfill or submicron particle composite, rubber compositefinishing cups and aluminum oxide pastes may be used to place the final finish.

Occlusion plays an important role in the longevity of a restoration. The restoration

should be in light occlusion (especially protrusive), since composites expand slightly

over time.


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Modified Class IV Tooth Preparation:

The modified Class IV preparation for composite is indicated for smallor moderateClass IV lesions or traumatic defects. The objective of the tooth preparation is to

remove as little tooth structure as possible, while removing the fault and providing

for appropriate retention and resistance forms.

Remove any existing lesion or defective restoration with a suitable size round bur or

diamond instrument and prepare the outline form to include weakened, friable

enamel. Usually little or no initial tooth preparation is indicated for fractured incisal

corners, other than roughening the fractured tooth structure.

The cavosurface margins are prepared with a beveled or flared configuration similar

to that previously described. The axial depth is dependent on the extent of the lesion,previous restoration, or fracture, but initially no deeper than 0.2 mm inside the DEJ.

Usually no groove or cove retention form is indicated. Instead, the retention is

obtained primarily from the bonding strength of the composite to the enamel and

dentin.

The treatment of teeth with minor traumatic fractures requires less preparation than

the beveled conventional example. If the fracture is confined to enamel, adequate

retention usually can be attained by simply beveling sharp cavosurface margins in

the fractured area with a flame-shaped diamond instrument followed bybonding.


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SPECIFIC FINISHING MATERIALS:

Burs

Six-fluted burs cut rapidly, are difficult to control, dislodge particles, and cause

fissuring .

They should not be used to finish composites.

Twelve-fluted burs may tear the resin matrix and actually weaken the composite

near the margins.

Use these burs for cutting preparations on indirect restorations. A 12-fluted bur

generally provides a smoother surface than a 15- m

diamond. Thirty-fluted burs effectively finish submicron composites.9

Forty-fluted burs can be used to trim excess composite resin from under gingival

tissues because the burs do not cut tissue and they leave a smooth burnished surface.

The main disadvantage is the slow cutting, which, without copious amounts ofwater, can cause the fine flutes to clog.

Diamonds

Coarse, medium, and fine diamonds are shown in . Coarse diamonds (>125 m) are

particularly useful in resin-to-resin bonding becausethe roughness creates a

mechanical interlock between the old and newly added composites. Fine diamonds

are ideal for gross contouring.

Micron diamonds are designed for use at slow speeds and with copious amounts of

water; however, most practitioners use them at near stall-out

high speed. The finish is slightly less smooth than the finish achieved with flexible

discs. Micron diamonds are suited for the lingual surfaces of incisors and the

occlusal surfaces of posterior composites.

Studies show that these diamonds do not damage the resin matrices and margins as

much as do some finishing burs

.

Stones

White and green stones, if used dry, can loosen fillers from the resin matrix andcause interfacial fractures in a composite, which can weaken a restoration. Since

they produce large amounts of heat, they should be used with large amounts of water as acoolant

Use of pins:

Retentive pins are not needed in resin composite restorations. The adhesive

technique provides sufficient retention, and the use of metallic pins in resin

composite restorations can greatly reduce the esthetic appearance.


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water.


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Case presentation:

A 55-year-old female patient presented with fractured

maxillary right and left central incisors . Upon self-

assessment, the patient requested the most conservative

and aesthetic restorative procedure available.An enamel defect was evident in the maxillary left

central around the middle one third of the tooth. Shade

determination was accomplished using acustomfabricated shade comparison, instrumental

shade, and previsualized color mapping.

To facilitate access to the cervical region of the tooth,the field was first isolated with a rubber dam using a

modified technique. This process involved the creation

of an elongated hole that allowed placement of the

rubber dam over the retainers to achieve adequate fieldcontrol.

Once the extent of the preparation was determined, acervical chamfer 0.3 mm in depth was

placed 2 mm long around the entire margin to increase

the enamel-adhesive surface and to provide sufficientbulk of material at the margins.


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A scalloped bevel on the chamfer was placed to break up the straight chamfer line with a long

tapered diamond. Since the margin was on enamel,a 0.5-mm bevel was placed on the gingival

margin to reduce microleakage with a needle-shaped fine diamond. The lingual aspect of thechamfer was extended 2 mm onto the lingual surface, but not onto the occlusal contact area.

The margin should not end on the occlusal

contact area unless relocating it to a contact-freearea would require excessive reduction of

healthy tooth structure. The preparation was

completed with a finishing disk and polishedwith rubber cups that contained a premixed

slurry of pumice and 2% chlorhexidine. The

preparation was rinsed and lightly air dried, and

a soft metal strip was placed interproximally toisolate the prepared tooth from the adjacent

dentition. A two-component self-etch was

applied to the preparation and light cured . The

Proximal Adaptation Technique in theInterproximal Zone Since composite does not

have hydroxyapatite crystals, enamel rods, anddentinal tubules, the final composite restoration

requires the clinician to create the illusion of the

way light is reflected, refracted, transmitted, and

absorbed by these microstructures of the dentinand enamel.

Therefore, in recreating the proximal surface,a similar orientation of enamel and dentin is

required. Since a silhouette of the cavity form is highlighted by the darkness of the oral cavity, it is

necessary to use an opacious dentin replacement with higher color saturation. This ensures thatwhen light strikes the optically denser dentin with more color saturation, more light is reflected

back to the eyes.

To reproduce the optical effects of the enamel, a

translucent composite encapsulates the inner

dentin core and alters the quantity and quality of

the light as it is reflected back to the eyes. Aninfinitesimal amount of glycerin was applied to

the mesial surface of the maxillary left central

with unwaxed floss. The proximal adaptationtechnique was utilized because it allows optimal

adaptation of the initial composite layer to the

adjacent tooth without using a mylar plasticstrip. Although studies indicate that a smooth

surface can be attained with the mylar strip,

improper proximal adaptation can result in

inadequate contact, improper anatomical formand shape, and surface defects.

Opacious dentin replacement was selected forstrength and color, and the most suitable

restorative material for the core of these

restorations was the hybrids and themicrohybrids. Because these small-particle

hybrids have similar refractive properties to that

of dentin and a variety of color selections, they

imitate the natural tooth structure well and have enough resistance for most occlusal stress-bearingregions in the anterior segment. The Artificial Dentin Core The initial layer the artificial dentin

body of opacious A03-shaded composite resin was applied and contoured with a long-bladed

composite instrument and smoothed out with an artists sable brush. This step was crucial and eachincrement was polymerized for 10 seconds, which allowed placement of subsequent increments

without deforming the underlying composite layer.


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An elliptical increment of opacious A03-shaded hybrid composite was placed from the

incisolingual aspect. Since surface irregularities could have interfered with placement of the tints

for internal characterization, this step was crucial. To prevent overbuilding of the artificial dentinlayer, it is imperative to monitor the composite from the incisal aspect to provide adequate space

for the final artificial enamel layer.

Internal Characterization:

A thin layer of translucent composite was applied and cured to create a light-diffusion layer and

provide an illusion of depth. The translucent layer caused an internal diffusion of light and controlluminosity within the internal aspect of the restoration.

A diluted white tint was applied to specific regions of

the restoration using light brush strokes to create a

cloud effect corresponding to the contralateral centralincisor and shade diagram prior to polymerization .

To alter the chroma and disguise the fracture line, a

yellow tint was diluted with untinted resin and placed

along the fracture line and on specific regions in theincisal third. These techniques utilize color variation

to emphasize the tooth form and instill the restorationwith a threedimensional effect. The Artificial Enamel

Layer To recreate the natural translucency of the

enamel, the artificial enamel layer of white translucent

(WT) shaded composite was applied and contouredwith a long-bladed composite & smoothed with a #4

artists sable brush.

This layer was light cured from the facial and the lingual for 40-second intervals, respectively.Anticipating the final result and developing the restoration in increments while considering the

occlusal morphology and occlusal stops allowed the clinician to minimize finishing procedures and

results in a restoration with improved physical and mechanical characteristics with lessmicrofracture. Once the final layer of composite was placed, and prior to final cure, an oxygen

inhibitor was applied in a thin layer with a brush to the surface of the re storation and light cured

for a 60-second postcure from the facial and lingual aspects.The restoration of the defect in the middle one third of the maxillary left central utilized the

previous described self-etch adhesive protocol and an A-3 artificial enamel layer was applied and

contoured with a long-bladed composite

instrument and smoothed out with a #4 artistssable brush. The same preparation design,

adhesive protocol, and restorative recipe as the

previously restored maxillary right central wasused on the facial and incisal edge of the

maxillary left central incisor. The Final

Restorative Phase Finishing and contouringwas performed to ensure maintenance of a

smooth surface texture.

In this case, particular attention was given not

only to the relationship between the expanseand direction of the marginal ridge, lingual

fossa, and the anatomic variations of the teeth that will be adjacent to the restoration, but also to

the light refraction and surface reflection resulting frommicrostructure of the tooth surface.

To reproduce the shape, color, and gloss of the natural dentition while enhancing the aesthetics and

longevity of the restoration, the following protocolwas implemented.

A long, needle-shaped finishing bur was used on

the labial aspect

to ensure development of proper anatomicalcontours . The lingual surface was contoured and

smoothed with #16 and #30 fluted egg-shaped

finishing burs used dry with light pressure toprevent heat buildup.

This dry finishing allowed the clinician to visualize

the margins and contours with the adjacent toothand the shape of this bur conforms to the

appropriate curvature of the morphological lingual

contours of the tooth and restoration.


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The interproximal region was finished and refined with silicon carbide finishing strips while

contouring and finishing on the proximal, facial, and incisal angles was performed with aluminum

oxide disks. These were used sequentially according to grit and ranged from coarse to extrafine.The extrafine finishing disks were used to impart a high luster while maintaining the existing

texture and surface anatomy.

The final polish was initiated with prepolish and high-shine silicone rubber points composed ofaluminum oxide particles and silicone that permit surface defects to be effectively eliminated. The

definitive polish and high luster was ccomplished with a soft white goat hair brush with composite

paste and a cloth wheel using staccato motion. The contact was tested with unwaxed floss toensure the absence of sealant in the contact zone and to verify adequate contact and the absence of

a gingival overhang and the margins inspected. The rubber dam was removed and the patient was

asked to perform closure without force and then centric, protrusive, and lateral excursions. Any

necessary occlusal equilibration was accomplished with #12 and #30 egg-shaped finishingburs and the final polish was repeated.

The surface quality of the composite is not only influenced by the polishing instruments and

polishing pastes but also by the composition and the filler characteristics of the composite.

The newer formulations of composites with smaller particle size, shape, and orientation provide alevel of polishability that

compares to porcelain andenamel. Although clinical

evidence of polishability with

these new small-particle hybrids

appears promising, the long-termdurability of the polish will need

to be evaluated in future clinical

trials. The postoperative resultsreflect the harmonious

integration of composite resin

with natural tooth structure.

Restoration of Class

IV Fractures using nano composite:

A comprehensive clinical and radiographic examination is first performed , and all goals for the

treatment are determined. Once the patients expectations have been discussed and a diagnosis hasbeen reached, a definitive treatment plan is identified. When direct resins are to be used for the

restorations, composite shades are selected prior to rubber dam placement to prevent improper

shade matching via tooth dehydration. Once anesthesia is administered to the patient, the teeth areisolated to ensure adequate field control and protection against contamination.

For a Class IV fracture, a chamfer preparation (approximately 0.3 mm in depth) is placed aroundthe entire margin to increase the enamel-adhesive surface and provide a sufficient bulk of material

at the margins.

Using a long, tapered diamond bur, a scalloped bevel should be placed on the chamfer to break upthe straight chamfer line. If the margin is confined to the enamel surface, a bevel of 0.5 mm should

be placed on the gingival margin to reduce microleakage.

The lingual aspect of the chamfer is extended 2 mm to the lingual surface. The margin should notend on the occlusal contact area unless the operator is relocating it to a contact-free area that would

require excessive reduction of healthy tooth structure. The preparation is completed with a

finishing disk and polished with rubber cups that contain a premixed slurry of pumice and 2%chlorhexidine. The preparation is rinsed and lightly air dried, and a soft metal strip is placed

interproximally to isolate the prepared tooth from the adjacent dentition.

The total-etch technique is utilized for such fractures due to its ability to minimize the potential of

microleakage and enhance bond strength to dentin and enamel.The preparation is etched for 15 seconds with 37.5% phosphoric acid semi-gel (eg, GEL-Etchant,

Kerr/Sybron, Orange, CA), rinsed for 5 seconds, and gently air-dried for 5 seconds. A hydrophilic

adhesive agent (ie, Optibond Solo Plus, Kerr/Sybron, Orange, CA) is then applied for 20 secondswith a disposable applicator using continuous motion, and excess resin is removed prior to

polymerization.

A small amount of glycerin is applied to the mesial surface of the adjacent tooth with unwaxedfloss. This proximal adaptation technique allows the author to optimally adapt composite resin to

the adjacent tooth without using a mylar plastic strip interproximally. Although the literature has

indicated that a smooth surface can be attained with a mylar strip, improper proximal adaptationcan result in inadequate contact, improper anatomical form and shape, or surface defects.


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The first layerthe artificial dentin bodyof nanoparticle hybrid resin (eg, Premise,

Kerr/Sybron, Orange CA; Filtek Supreme, 3M Espe, St. Paul, MN) is applied, adapted and

contoured to the proximal surface of the adjacent incisor with a long-bladed composite instrumentand smoothed with a sable brush. Each increment is polymerized for 40 seconds, which allows

placement of subsequent increments without fear of deforming the underlying composite layer.

An elliptical-shaped increment of a nanoparticle hybrid composite is then placed from theincisolingual aspect and contoured to form an incisal matrix prior to polymerization from the facial

and lingual aspect .

Since surface irregularities can interfere with the placement of tints required for internal

characterization, this step is crucial. In order to prevent overbuilding of the artificial dentin layer, itis imperative to monitor the composite from the incisal aspect to provide adequate space

for the final artificial enamel layer.

A thin layer of resin can be applied and cured to create a light-diffusion layer and provide an

illusion of depth for restorations of limited thickness. This translucent layer will cause an internaldiffusion of light and control luminosity within the internal aspect of the restoration.

As directed by the color map of the contralateral tooth, tints are placed along the fracture line andon specific regions in the vertical invaginations and light cured for 40 seconds. This internal

characterization technique utilizes color variation to emphasize the tooth form and to instill the

restoration with a threedimensional effect. To re-create the natural translucency of the enamel, the

final enamel layer of composite resin is applied and contoured . A precut mylar strip is placed andadapted over the facial surface and light cured from the facial and the lingual aspects for 40-second

intervals, respectively .

The initial contouring is performed with a series of finishing burs in order to replicate natural formand texture.

The facial contouring is initiated with 30-fluted, needle-shaped. The lingual surfaces are contoured

with 30-fluted football-shaped burs. Finishing the proximal, facial, and incisal angles is performedwith aluminum oxide disks and finishing strips. These are used sequentially according to grit and

range from coarse to extra fine. Finishing burs, diamonds, rubber wheels, and points are used to

create indentations, lobes, and ridges . A soft goat-hair brush is used with composite polishingpaste to impart a high luster for the restoration while maintaining its existing texture and surface

anatomy. The final surface gloss is achieved with a dry cotton buff using an intermittent staccato

motion applied at conventional speed.


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References:

1.Art and science of operative dentistry.

2.Fundemental of operative dentistry.

3.Art and science of porcelain.

4.Tooth colored restoratives.5.Ethetics in dentistry.

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