Quality Resource Guide

Posterior Composites 6th Edition

www.metdental.com

adjacent proximal surface while the contact-

related increment of composite is cured. A hand

instrument with a large surface area (

e.g.,

a small

football- or round-shaped burnisher) is well suited

for that purpose. Once this increment is cured,

the proximal contact is established and remaining

increments can be inserted and polymerized.

Research has indicated that efficient light curing

requires a curing device with a minimum energy

output of 300 mW/cm2. The energy output of

any curing device should be monitored regularly

with a curing radiometer. Even though composite

increments of up to 2 mm can be appropriately

cured with modern curing lights, this can be

affected by (1) the composite’s shade and opacity,

(2) the composite’s distance from the light source,

and (3) the power of the light source. The number

and distribution of increments varies with the

preparation’s geometric shape and size.

Figure 3

illustrates the recommended incremental insertion

and polymerization technique that should be used

to restore proximal boxes. Once the proximal

box(es) is(are) restored, the occlusal box can be

approached as a Class I preparation.

In the technique illustrated in

Figure 4

and

used to complete the restorations illustrated in

Figure 2

, the composite application is guided

by dental anatomy. Shaping the entire anatomy,

or most of it, during insertion of the composite

minimizes the need for burs during the finishing

phase, eliminating complications associated

with this procedure. The occlusal sculpture is

guided by the remaining cusp inclines, similarly

to the technique used for sculpting amalgam

restorations. Uncured composite can be effectively

carved, shaped, and smoothed with a variety of

instruments and brushes to establish contour and

surface smoothness.

In the cases that illustrate this review, a composite

with low value (darker overall shade) was used

to restore the dentin aspect of the preparation.

This stage is typically completed using two

increments of composite, cured individually for

40s. (It is important to thoroughly cure these

increments due to their distance from the light

source and to their relatively dark shade.) The

final occlusal stratum of the restoration is built

in segments, with a more translucent and/or

high-value shade. In the technique described,

each increment of the enamel stratum is cured

initially for 5s; after all occlusal elements have

been developed, a thorough 40s light-curing

cycle is performed with a layer of glycerin gel

covering the surface of the restoration to avoid

formation of an oxygen-inhibited resin layer. The

most efficient and predictable result is obtained

when each cusp area is restored independently,

as illustrated in

Figures 4K and 4L

. Because

this technique respects the anatomical elements

present in the unprepared tooth structure, a

physiological contour is “naturally” reproduced in

the restoration, minimizing occlusal adjustments.

As noted earlier, bulk-fill composites have

gained considerable attention recently.

While

the clinical research on these composites is

not abundant, preliminary laboratory and short-

term clinical studies indicate that when correctly

used (meaning correct case selection, tooth

preparation, insertion and adequate light-curing)

bulk-fill composites can be successful.

Bulk-filling

will make it more difficult to develop the occlusal

anatomy than when an incremental technique

is used as described previously, but will be

expeditious in that all (or most) of the composite

is inserted and cured in one single increment.

skilled operator can develop effective occlusal

anatomy using a bulk-fill composite approach.

No more than two or three hand instruments are

needed in the posterior composite armamentarium.

One thin, round-ended composite spatula, and

one double-sided composite condenser, both

metallic, are enough for inserting and shaping

posterior composites. The sharp end of an

explorer tine can be used to sculpt primary and

secondary grooves on the composite before it is

cured.

Contemporary posterior composites have

much better handling properties when compared

to earlier composites. Still, some composites

might feel “sticky” and difficult to handle.

The

best technique to avoid having the composite

stick to the instrument and not to the tooth is to

use a clean, dry instrument. The instrument can

be wiped with a piece of dry gauze often during

the procedure. Lubricating the composite spatula

or condenser with bonding agent will compromise

the restoration by imbedding fluid resin in it, and

alcohol should also be avoided.

Finishing, Polishing and Occlusal

Adjustment

Ideally, composite restorations should not have

to be finished. The use of cutting instruments on

the polymerized resin can induce flaws on the

tooth-restoration interface and on the restoration

surface, compromising its performance. When

the described stratified incremental technique is

utilized, and an anatomical matrix is used when

a proximal box is involved, the need for finishing

with hand or rotary instruments is minimized

because the restoration will have the required

morphology upon curing.

However, it is virtually impossible to insert the

composite to the exact desired final contour with

available materials and instruments, particularly

when a proximal surface is restored. As

necessary, flashes of composite can be trimmed

with a surgical blade or reciprocating diamond

blades. Sequential aluminum oxide-impregnated

finishing discs are good instruments to contour

and polish the accessible facial and lingual

embrasures and marginal ridges of posterior

composites. If necessary, the anatomy of the

restoration can be refined with medium, fine and

super-fine diamonds applied intermittently with a

high-speed handpiece running at reduced RPM.

These instruments should be used in a dry field

to facilitate visualization and avoid inadvertent

cutting of marginal enamel.

Figure 3

Diagrammatic representation of recommended

incremental insertion and polymerization technique

for posterior composite restorations.