Comprehensive Composite Restoration in Cosmetic Dentistry
Posted: Thursday, March 08, 2007
by Jeremiah Lewis
http://www.breastimplants411.com
A comprehensive composite Restoration does not refer to and is not ideal for full-mouth rehabilitation but is ideal for specific restorative situations and smile improvements. This article describes all of the factors that determine when composite is appropriate and what steps are required to maximize results. There are 6 principles used to treatment plan and 6 principles applied to composite restoration. These 12 principles become a checklist to improve composite use and results (Figure 1).
Posterior composites have the least impact on smile design. Replacement of amalgam changes silver to tooth color and minimizes show-through to the buccal aspects. Posterior composite restorations are very technique sensitive and require special attention to the principles presented.9-11
CASE ONE: POSTERIOR COMPOSITES
In this case, the patient presents with failing amalgam restorations and interproximal decay on the first and second molars requiring restoration (Figure 2A). After administration of anesthetic and rubber dam isolation, the amalgam and decay are removed, the enamel is finished, and matrix systems are placed. Enamel and dentin are bonded with etching and application of OptiBond® Solo (Kerr Corp., Orange, CA) to form a resin hybrid layer. (Figures 2B and 2C). Composite (Premise™ body shade, Kerr) is added in layers while touching no more than 2 walls at a time to minimize stress from shrinkage (often referred to as the C-factor) and replicate dentin color. Enamel-shaded composite (Premise translucent) is layered, cured, shaped, custom colored, and polished
Treatment Planning
Patient
care requires comprehensive treatment planning. Smile design is an
important aspect of comprehensive treatment planning and composite
restoration. Dominance, proportion, perspective, symmetry, and balance
produce a pleasing appearance.12-17 Normal contacts, long axis,
gingival apex, incisal and gingival height of contour, parallel anatomy
from tooth to tooth–including the silhouette of the teeth and face
anatomy–define normal pleasing teeth and smile relationships. 5,18,19
It is normal to see all oval or all square teeth but it is not pleasing
to mix them. The ideal relationships can be seen in Figure 3. 
In 1978, Levin described the principle of golden proportion to evaluate
facial features, smile design, and tooth proportions. 20 The golden
rule is an ancient principle used in mathematics, art, and architecture
to provide a guide for esthetically pleasing proportion. A line is
divided into 2 parts so that 1 part is the mean and the other part is
the extreme. The ratio of proportion is 1 to 1.618, as mean to extreme. Interestingly, the same progression of numbers can be achieved by multiplying 1.618 or dividing by 0.618.21
This proportion is applied to buildings, drawings, body parts, and
smiles. In addition, to make a smile pleasing, a line drawn through the
pupils of the eyes should be perpendicular to the midline.The lip line
and overall incisal edges of the teeth within an arch should be
parallel to the line drawn through the pupils. A smile’s fit within a
face must include smile size, shape, position, etc. A line drawn following the outline formed by the incisal edges of the maxillary teeth should be 1 mm to 3 mm parallel/ equidistant to the lower lip line. Variation occurs with age.Older individuals loose elasticity in the lips, which results in sagging. Prominence of the mandibular teeth and diminution of the maxillary teeth results from this sagging.
A masculine smile forms a straight smile while a feminine smile forms a
curved smile.12-15 An anterior tooth compared to the adjacent distal
tooth has an extreme-tomean proportion when looking straight at the
overall smile. Golden proportion exists thoughout a smile, including
the cervical apex of a tooth to the height of the gingival papillae
relative to the height of the gingival papillae to the incisal edge of
a tooth and the mesial of the central incisor to the distal of the
cuspid compared to the distal of the cuspid to the distal of the last
posterior tooth.20 Esthetic treatment planning is important even when
small restorations are anticipated. Completed work may need to be
redone if comprehensive treatment is done later and overlaps with
already completed work. For example, class V and class III restorations
would be part of a veneer and would not be done as 2 separate
procedures on the same tooth. 
Tooth Shape, Position, and Color Tooth position is determined by arch shape, arch position, occlusion, normal tooth height, and orientation. Anterior maxillary teeth tip to the mesial. The long axis of the maxillary cuspid normally tilts to the mesial and appears to have a lingual tilt from the gingival height of contour to the incisal edge. Anatomic features such as line angles, height of contour, gingival contour, embrasure form, contacts, incisal edge, facial contour and texture, and small anatomy such as grooves or dimples define tooth shape. Each anatomic feature varies depending on general tooth shape such as oval, tapered, or square.22 Enamel is translucent and prismatic with slight hue, chroma, and value. Dentin shows through enamel to create tooth color. In the center portion of a tooth, enamel is thickest and shows less dentin. Incisal and interproximal enamel has no dentin behind it when viewed from the facial aspect so it shows through the darkness of the back of the mouth to look gray. Enamel thins in the gingival third of a tooth, which increases yellow color. Color variation occurs from dentin discolorations showing through enamel, maturation defects, staining, hypocalcifications, cracks, and enamel defects.23,24
Composite restorations restore tooth position, structure, and color. Color is a unique science of how the eye and mind see light, including hue, value, chroma, translucency, and fluorescence. Hue is the color quality determined by the color’s wavelength (such as red or blue). Value is the lightness or darkness of a color. Chroma is the saturation or brightness of a color. Translucency is the ability of light to pass through material. Fluorescence is light emitted during absorption of radiation or other invisible light.
Light changes with reflection, refraction, and absorption caused by composite surfaces, matrix, and fillers.25,26 The components of a restoration including composite, tints, opacity, and tooth structure create subtractive, additive, or partitive color. Subtractive color is the process of mixing pigments together. Additive color is the method of creating color by mixing various proportions of 2 or 3 distinct stimulus colors. Partitive color uses small dots or patches of colors placed adjacent to each other. From a distance, the eye mixes them to form a new color.Color change occurs unintentionally if a clinician does not understand these concepts. For example, if a dentist places a blue tint on yellow composite to replicate an incisal edge, green is produced. The dentist and patient together define treatment goals. A perfect Hollywood smile or a natural smile are 2 common, general goals.25,26 A patient decides which smile defects are acceptable when creating a natural smile. Results are further limited by general appearance, emotional influences, and environmental considerations. For example, people in Mongolia would look awkward with the Hollywood smile. There are physical, financial, and psychological limitations as well. Financial and psychological factors limit the materials used, the amount of dentistry done, and a timeline for completing work.27
CASE TWO: COMPOSITE VENEERS
In this case, a patient presents with yellow, chipped, and poorly
restored anterior teeth (Figure 4A). Improper tooth shape, proportion,
position, and color is seen (Figure 4B). The patient requested
composite restorations. The old composite is removed and the teeth
prepared for composite veneering. After bonding and matrix placement,
composite (Point 4TM, Kerr) is placed and shaped with composite
instruments before curing. 
Final contouring and surface texturing is done with finishing burs
after curing. Polishing is completed with sandpaper discs, polishing
cups and points, and polishing pastes (Figures 4C and 4D). Composite Restoration
Composite restoration requires proper tooth preparation, bonding,
composite selection, placement, pre- and postcure shaping, and
finishing. Tooth preparation gains access to caries, removes caries,
increases surface area, creates mechanical retention, and finishes
enamel margins. 28,29 Preparation design improves resistance to forces analyzed by force intensity, frequency, duration, and direction.
30,31 Carbide burs often create access to cavities while diamond burs
are commonly used to increase surface area, create cross-sections of
enamel rods, and remove tooth structure such as sclerotic or carious
dentin for improved bond strength. Bonding supports composite, reduces
sensitivity, minimizes microleakage, and lessens the need for
mechanical retention and resistance form.32,33 Enamel bonding is a
simple procedure and predictable while dentin bonding is technique
sensitive, and varies from manufacturer to manufacturer.
34 Special procedures are required for bonding to materials such as composite, porcelain, and metals. Microetching, silination, and mechanical retention are common techniques. Composite selection is based on esthetic characteristics, material strength and wear, and ease of placement, shaping, and polishing. Composite replicates dentin and enamel with proper hue, chroma, value, translucency, and fluorescence. Additional materials are required to maximize results. Tints and opaques custom colorize composite and block out color.35 Opaque composite is also used to block out defect color when tooth backing exists and block out the darkness from the back of the mouth when no tooth backing exists. No tooth backing exists if there is no tooth structure behind a filling when viewed from the facial.36 The back of the mouth receives little light and appears dark.
A translucent composite placed in a defect with no tooth backing shows through this darkness and appears dark or grey. Defects with tooth backing have different colors, depth, size, and locations. Defect color shows through composite if light intensity is high, the defect depth is shallow (which makes the composite layer thin), or if the composite is very translucent. Composite layering with appropriate opaque and translucent materials, proper defect preparation, and composite surface texturing is done to correct a large color change. Surface texturing creates small areas of light reflection and light refraction that makes composite look lighter.
CASE THREE: CLASS IV RESTORATION
This patient presented with a traumatic fracture of the left central
incisor creating a smile defect (Figure 5A). In this case, composites
(Point 4 body shade and enamel shade) are layered to replace dentin and
enamel. Tooth anatomy replicates a symmetrical view of the right
central incisor. The line angles, tooth contours, long axis, incisal
edge anatomy, surface texture, and color that creates a natural
appearance should be observed (Figure 5B). 
Composite strength is defined by shear, compressive, tensile, and
modulus of elasticity, etc.37,38 Composite is made stronger with
increased thickness, reduction of internal stress from curing shrinkage
by layering techniques, minimizing the C-factor (the number of walls joined over the number or walls not touched),39 and by the ability to stop crack propagation as occurs with larger filler particles. Unfortunately, large filler particles create increased wear. Matrix resin wears to expose more surface area of a large particle, which causes it to dislodge, and makes the composite restoration wear excessively.40-43
Restoration strength is defined by composite strength, composite-to-tooth interface strength, and tooth structure strength. Forces on composite restorations can be internal, mechanical, or thermal.44-47 Internal stress is created by resin matrix shrinkage. Stress is created within the resin matrix and at the resinto- filler interface. Mechanical forces are defined by direction, duration, intensity, and frequency.48 Thermal coefficient of expansion applies force, which is created when hot or cold is applied, and the composite and tooth structure contract and expand.
Composite wear is critical to composite selection particularly if forces are strong and direct. Adhesive, abrasive, chemical, and fatigue wear increase with increased contact.49-51Wear causes functional or esthetic failure. Many composite characteristics (such as wear) are harder to quantify because there is variation from in vivo versus in vitro studies. Composite is selected by placement characteristics. Proper composite placement produces ideal tooth color. Proper matrix techniques confine material within the restoration boundaries. A material that is too firm will displace a matrix. Composite needs to be able to flow enough to wet surfaces so that air is not trapped at the tooth-to-composite or composite-to-composite interfaces and yet be firm enough that it can be shaped before curing. Composite cannot be so light sensitive that it sets before intentional curing. Layers must join using the oxygen inhibited layer as occurs during layering techniques.38,52 Composites such as packable composites minimize joining of layers because the highly filled material has less resin exposure.
Composite shaping, finishing, texturing, and polishing should be easy. Different composites require different instrumentation and techniques,53-55 which are usually defined by the manufacturer. Selection of instruments, sandpaper discs, polishing cups and points, brushes, cloth wheels, finishing burs, diamond burs, and pastes are critical to proper polishing and finishing.
CASE FOUR: PEG LATERALS
A 15-year-old adolescent boy presents with peg laterals (Figures 6A and
6B). The peg laterals are prepared with a diamond bur to clean the
enamel surface and increase surface area. Enamel bonding is completed
by acid etching and application of OptiBond Solo. Composite (Point 4
body shade) is added freehand to provide general shaping without
touching the adjacent teeth, which helps support the matrix. Composite
is cured and a clear plastic matrix is placed. A final composite layer
(Point 4 translucent) is added, shaped, and cured. Final shaping and
smoothing is done with sandpaper discs. Surface texturing is
accomplished with a diamond bur and final polishing is accomplished
with polishing cups and paste (Figures 6C and 6D).CONCLUSION
Composite restoration involves 12 major areas of knowledge. A dentist needs to understand each aspect of restoration or the results may be imperfect.These restorations may in turn require replacement if they are esthetically inadequate, fracture, wear, leak, change appearance, or are painful.
ACKNOWLEDGMENTS
Photos are published with the permission of www.dentalcomposites.com.
DISCLOSURE
The author received financial/materials support from Kerr Corporation.
Cosmetic Dentist 411 is a comprehensive website on cosmetic dentists and cosmetic dentistry, including dental implants, veneers, and teeth whitening. Visit Cosmetic Dentist 411 for more information.
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