Quality Resource Guide

Posterior Composites 6th Edition

www.metdental.com

rubber dam and the papillae, prevents bleeding

that

could

jeopardize

bonding

procedures,

and promotes slight teeth separation favoring

matrix application and achievement of adequate

proximal contacts. Anatomical wooden wedges

are most appropriate, but plastic WedgeGuards®

(Ultradent Products, Inc. South Jordan, UT) or

FenderWedges® (Garrison Dental Solutions,

Spring Lake, MI) are appropriate as well and

provide additional protection of the adjacent tooth

surface while cutting the adjacent proximal box.

Matrix Application

(for Occlusoproximal Preparations)

Matrices are often needed to restore proximal

surfaces of posterior preparations. Matrix selection

and placement is critical when restoring with

composite, which is a non-rigid, non-condensable

material.

Individual, thin precontoured metallic

matrices are very suitable to obtain good contour and

effective interproximal contacts without composite

overhangs in most situations. Care should be taken

to avoid collapse of the matrix in the preparation,

which would generate inappropriate contour.

Various excellent sectional matrix systems are

available (

e.g.

, V3 Triodent System, Ultradent,

South Jordan, UT; Composi-Tight 3D, Garrison

Dental Solutions, Spring Lake, MI; Palodent,

Dentsply International, York, PA) and include a

metallic ring to stabilize the matrix system and

promote additional tooth separation. Such rings

should be used only when (1) there is no remaining

proximal contact between the tooth being restored

and the adjacent tooth, (2) they do not interfere

with the matrix contour, (3) the remaining tooth

structure is strong enough to support the ring, and

(4) they can be placed securely not interfering with

the wedge.

Matrix application techniques vary depending

on the proximal box faciolingual extension. In

conservative preparations where the faciolingual

extension does not break contact with the

adjacent tooth, a conventional metallic matrix

can be used. For these cases these bands

are easier to apply than sectional matrices.

In larger preparations where the faciolingual

extension does break contact with the adjacent

tooth, sectional, precontoured matrices are

recommended. However, very wide faciolingual

preparations should be restored with composite

infrequently as discussed in previous sections.

Regardless of the type of matrix used, the

clinician should always stabilize the matrix with

an anatomic wooden or plastic wedge. The

wedge should be positioned gingival to the

preparation’s gingival margin, as not to interfere

with the restoration’s contour. After the matrix

is secured with a wedge, it should be burnished

internally against the adjacent surface to provide

for appropriate contour and proximal contact.

Because light-cured composites are plastic, non-

rigid materials, matrix installation and modeling

prior to insertion of composite is essential in order

to obtain a proper restoration.

Application of Dental Adhesive

Regardless of the type of adhesive used, it

should be applied and polymerized after matrix

application and wedging, which prevents etching

and bonding of adjacent surfaces/teeth. Care

should be taken to avoid adhesive pooling in areas

adjacent to the matrix and on internal angles on

the preparation.

As discussed previously, the use of liners and

bases under posterior composites is controversial.

It is generally accepted that hybridization of

the prepared tooth substrates with an adhesive

system is the optimal treatment to seal the

preparation and protect the pulp-dentin complex

under composite restorations. Liners and/or bases

are recommended only when the preparation

is deemed deep. In small, non-contaminated,

non-hemorrhagic mechanical pulp exposures, the

pulp and immediate surrounding dentin should

be covered with a thin layer of hard-set calcium

hydroxide cement or an MTA medicament. Then,

a 1-2 mm thick layer of a resin modified glass-

ionomer cement (RMGI) should be placed to

protect the pulp dressing material. In deep, non-

exposed preparations the RMGI can also be used

as the initial increment of the restoration. Liners

and/or bases, if used, should in general not be

exposed at the restoration’s margins.

Composite Placement and

Polymerization Technique

Techniques for insertion and polymerization of

posterior composites have been extensively

researched. Horizontal, oblique, vertical, bulk,

and incremental techniques have all been

recommended.

Microleakage

assessments

comparing different insertion and polymerization

techniques are not conclusive, and no single

technique has been universally accepted.

Several manufacturers claim that a more profound

depth of cure can be achieved with some

composites, but this assertion has been disputed.

Incompletely cured composites can cause adverse

pulp reactions when in direct contact with vital

dentin, through leakage of unreacted monomers

via dentinal tubules. In addition, the material’s

properties and bond strengths are substantially

compromised when the composite is not fully

cured. High-intensity curing lights and new curing

technologies are promising in providing faster and

more thorough composite polymerization, as was

discussed earlier. However, initial research on

high-intensity curing lights demonstrate that the

high energy output per unit of time might lead to

more shrinkage stress than when conventional

curing techniques are used. Polymerization-

derived stresses can disrupt the composite-

preparation bond, and/or diffuse stresses to the

tooth structure, compromising the integrity of the

tooth-restoration unit.

The incremental insertion and polymerization

technique

provides

enhanced

control

over

application and polymerization of individual

increments

composite.

The

incremental

technique also allows for (1) orientation of the

light beam according to the position of each

increment of composite, enhancing the curing

potential, (2) intrinsic restoration characterization

with darker or pigmented composites, and (3)

sculpture of the restoration occlusal stratum with

a more translucent material simulating the natural

enamel.

Tight proximal contacts can also be better

achieved when composite is applied in increments.

The matrix can be held in close contact with the