How Dental Restoration Materials Compare


Robert Baratz, M.D., D.D.S., Ph.D., Stephen Barrett, M.D.
October 30, 2008

Dental restorations can be classified into two types. Direct restorations are done by inserting filling material directly into the tooth. Indirect restorations are fabricated outside of the mouth.

In recent years, there has been a marked increase in the development of aesthetic materials made of ceramic and plastic. These mimic the appearance of natural teeth and are more aesthetically pleasing where they will be visible. But the strength and durability of traditional materials still make them useful, particularly in the back of the mouth where they must withstand the extreme forces that result from chewing. The traditional materials include gold, base metal alloys, and dental amalgam.

Amalgam, produced by mixing mercury and other metals, is still the most commonly used filling material. Some people have expressed concern about amalgam because of its alleged mercury content. In fact, amalgam is composed mostly of complex compounds where the mercury is bound chemically to the other ingredients. Although mercury by itself is classified as a toxic material, the mercury in amalgam is chemically bound to other metals to make it stable and therefore safe for use in dental applications. In fact, amalgam is the most thoroughly studied and tested restorative material now used. Compared to the rest, it is durable, easy to use, and inexpensive. The safety and effectiveness of amalgam have been reviewed by major U.S. and international scientific and health bodies, including the American Dental Association; the National Institutes of Health; the U.S. Public Health Service; the Centers for Disease Control and Prevention; the Food and Drug Administration; and the World Health Organization. All have concluded that amalgam is a safe and effective material for restoring teeth.

The 2007 American Dental Association Survey of Current Issues in Dentstry found that dentists’ satisfaction with amalgam increased between 2000 and 2007. The data show:

Satisfaction level
2000
2007
Very satisfied
54.9%
67.9%
Somewhat satisfied
28.5%
26.2%
Somewhat dissatisfied
  7.4%
  5.2%
Very dissatisfied
  9.1%
  0.8%

 

The charts below are reproduced with the kind permission of the American Dental Association, which developed them to help dentists explain the relative advantages and disadvantages of the materials used in fillings, crowns, bridges and inlays. They provide a simple overview of the subject based on the current dental literature and are not intended to be comprehensive. The attributes of a particular restorative material can vary from case to case depending on a number of factors.

Direct Restorative Dental
Materials

FACTORS

AMALGAM

COMPOSITES
Direct and Indirect

GLASS
IONOMERS

RESIN-
IONOMERS

General
Description

A
mixture of mercury and silver alloy powder that forms a hard
solid metal filling. Self-hardening at mouth temperature.

A
mixture of submicron glass filler and acrylic that forms a solid
tooth-colored restoration. Self- or light-hardening at mouth
temperature.

Self-hardening
mixture of fluoride containing glass powder and organic acid
that forms a solid tooth colored restoration able to release
fluoride.

Self
or light- hardening mixture of sub-micron glass filler with fluoride
containing glass powder and acrylic resin that forms a solid
tooth colored restoration able to release fluoride.

Principal Uses Dental
fillings and heavily loaded back tooth restorations.
Esthetic
dental fillings and veneers.
Small
non-load bearing fillings, cavity liners and cements for crowns
and bridges.
Small
non-load bearing fillings, cavity liners and cements for crowns
and bridges.

Leakage
and
Recurrent
Decay
Leakage
is moderate, but recurrent decay is no more prevalent than other
materials.
Leakage
low when properly bonded to underlying tooth; recurrent decay
depends on maintenance of the tooth-material bond.
Leakage
is generally low; recurrent decay is comparable to other direct
materials, fluoride release may be beneficial for patients at
high risk for decay.
Leakage
is low when properly bonded to the underlying tooth; recurrent
decay is comparable to other direct materials, fluoride release
may be beneficial for patients at high risk for decay.

 Overall
Durability

 

Good
to excellent in large load-bearing restorations.
Good
in small-to-moderate size restorations.
Moderate
to good in non load-bearing restorations poor in load-bearing.
Moderate
to good in non load-bearing restorations; poor in load-bearing.

Cavity
Preparation Considerations
Requires
removal of tooth structure for adequate retention and thickness
of the filling.

Adhesive
bonding permits removing less tooth structure.
Adhesive
bonding permits removing less tooth structure.
Adhesive
bonding permits removing less tooth structure.
Clinical
Considerations
Tolerant
to a wide range of clinical placement conditions, moderately
tolerant to the presence of moisture during placement.

Must
be placed in a well-controlled field of operation; very little
tolerance to presence of moisture during placement.

 

 

Resistance
to Wear
Highly
resistant to wear.
Moderately
resistant, but less so than amalgam.

High
wear when placed on chewing surfaces.
Resistance
to Fracture
Brittle,
subject to chipping on filling edges, but good bulk strength
in larger high- load restorations.

Moderate
resistance to fracture in high-load restorations.
Low
resistance to fracture.
Low
to moderate resistance to fracture.
Biocompatibility
Well-tolerated with rare occurrences of allergenic response.

Post-Placement
Sensitivity
Early
sensitivity to hot and cold possible.
Occurrence
of sensitivity highly dependent on ability to adequately bond
the restoration to the underlying tooth.
Low. Occurrence
of sensitivity highly dependent on ability to adequately bond
the restoration to the underlying tooth.

Esthetics Silver
or gray metallic color does not mimic tooth color.
Mimics
natural tooth color and translucency, but can be subject to staining
and discoloration over time.

Mimics
natural tooth color, but lacks natural translucency of enamel.
Mimics
natural tooth color, but lacks natural translucency of enamel.
Relative Cost
to Patient
Generally
lower; actual cost of fillings depends
on
their size.
Moderate;
actual cost of fillings depends
on
their size and technique.

Moderate;
actual cost of fillings depends
on
their size and technique.
Moderate;
actual cost of fillings depends
on
their size and technique.

Average
Number of Visits To Complete
One. One
for direct fillings; 2+ for indirect inlays, veneers and crowns
.
One. One.

Indirect Restorative Dental
Material
s


FACTORS

ALL-PORCELAIN
(ceramic)

PORCELAIN Fused
to metaL

GOLD
ALLOYS (high noble)

BASE
METAL ALLOYS(non-noble)

General
Description

Porcelain,
ceramic or glass-like fillings and crowns.

Porcelain
is fused to an underlying metal structure to provide strength
to a filling, crown or bridge.


Alloy
of gold, copper and other metals resulting in a strong, effective
filling, crown or bridge.

Alloys
of non-noble metals with silver appearance resulting in high
strength crowns and bridges.
Principal Uses Inlays,
onlays, crowns and aesthetic veneers.

Crowns
and fixed bridges.
Inlays,
onlays, crowns and fixed bridges.
Crowns,
fixed bridges and partial dentures.
Leakage
and Recurrent Decay
Sealing
ability depends on materials, underlying tooth structure and
procedure used for placement.

The
commonly used methods used for placement provide a good seal
against leakage.  The
incidence of recurrent decay is similar to other restorative
procedures.
Durability Brittle
material, may fracture under heavy biting loads. Strength depends
greatly on quality of bond to underlying tooth structure.

Very
strong and durable.
High
corrosion resistance prevents tarnishing; high strength and toughness
resist fracture and wear.
Cavity
Preparation Considerations

 

Because
strength depends on adequate porcelain thickness, it requires
more aggressive tooth reduction during preparation.

Including
both porcelain and metal creates a stronger restoration than
porcelain alone; moderately aggressive tooth reduction is required.
The
relative high strength of metals in thin sections requires the
least amount of healthy tooth structure removal.
Clinical
Considerations
These
are multiple step procedures requiring highly accurate clinical
and laboratory processing. Most restorations require multiple
appointments and laboratory fabrication.

Resistance
to Wear
Highly
resistant to wear, but porcelain can rapidly wear opposing teeth
if its surface becomes rough.

Highly
resistant to wear, but porcelain can rapidly wear opposing teeth
if its surface becomes rough.
Resistant
to wear and gentle to opposing teeth.
Resistant
to wear and gentle to opposing teeth.
Resistance
to Fracture
Prone
to fracture when placed under tension or on impact.
Porcelain
is prone to impact fracture; the metal has high strength.

Highly
resistant to fracture.
Biocompatibility Well
tolerated.
Well
tolerated, but some patients may show allergenic sensitivity
to base metals.
 
Well
tolerated.
Well
tolerated, but some patients may show allergenic sensitivity
to base metals.
Post-Placement
Sensitivity
Sensitivity,
if present, is usually not material specific.

Low
thermal conductivity reduces the likelihood of discomfort from
hot and cold. 

High
thermal conductivity may result in early post-placement discomfort
from hot and cold.
 
Esthetics Color
and translucency mimic natural tooth appearance.
Porcelain
can mimic natural tooth appearance, but metal limits translucency.

Metal
colors do not mimic natural teeth.
Relative
Cost to Patient
Higher;
requires at least two office visits and laboratory services.

Higher;
requires at least two office visits and laboratory services.
Higher;
requires at least two office visits and laboratory services.
Average
Number of Visits To Complete
Minimum
of two; matching esthetics of teeth may require more visits.
Minimum
of two; matching esthetics of  teeth
may require more visits.
Minimum
of two

© American Dental Association. Updated, February 21, 2002

This article was revised on October 30, 2008.