Operative dentistry aje qualtrough, jd satterthwaite la morrow, pa brunton

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Chapter 1
Fig. 1.10
Rubber dam.
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Types of clamps for use with rubber dam
A vast array of rubber dam clamps is available, but there are prin-
cipally four design factors that differ between them. First, and most 
obvious, is that of size – small clamps are designed to be used on small
single-rooted teeth whereas the larger clamps are for use with molar
teeth. Clamps are available in a wide variety of sizes reflecting the
broad range of sizes of teeth (especially molars) that may be encoun-
tered. It is important to realise that if too small a clamp is used then
damage to the tooth structure may occur during placement or
removal and sensitivity may occur because of pulpal irritation arising
from the increased pressure on the tooth with too small a clamp. In
addition, if a clamp is too small for a particular tooth, then the bow of
the clamp will be stretched to such an extent that fracture of the bow
may occur either during, or after, placement. It is for this reason that
many clinicians secure one jaw to the other with a floss ligature before
application of the dam (though if the floss is left in situ after dam
placement it may cause leakage).
The jaws of clamps differ in two aspects, namely the presence or
absence of ‘wings’ and the orientation of the jaws. Winged clamps 
are designed with an extension to the jaws so that the clamp may be
positioned into the rubber dam, and clamp and dam applied simul-
taneously. Winged clamps also have the added advantage that the
working area is increased as the wings displace the rubber dam.
Wingless clamps do not have extension of the jaws and are placed at a
separate stage to the rubber dam, either before or after.
Clamps are retained on the tooth either through engaging the tooth
below the maximum bulbosity of the crown, or by actively ‘gripping’
the tooth surface. The former may be termed bland (or passive)
clamps and the jaws have a fairly flat orientation, the latter may be
termed ‘active’ clamps and these often have jaws that are angled 
gingivally with the points of the jaw closer together than a bland
clamp. Active clamps are usually more stable as they are more likely
to achieve four-point contact with the tooth. However, the tight fit
may cause some post-placement sensitivity and the gingival orienta-
tion of the jaws may traumatise the gingivae, as the area of engage-
ment with the tooth is more apical (though this may be an advantage
if some gingival retraction is required).
The final design difference relates to clamps that are specifically for
retaining rubber dam on anterior teeth while also having the ability to
retract the gingivae. These clamps, termed ferrier or butterfly clamps,
have a double bow and fine jaws that may be bent to alter the amount
Basic principles


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of soft tissue retraction that is provided. As the jaws of these clamps
are fine, they are not particularly stable and may require support (e.g.
with impression compound) to prevent scraping and damaging of the
tooth surface.
Thus, clamps for use with rubber dam (Fig. 1.11) may be:
• Various sizes depending on which tooth they are intended for
• Winged or wingless
• Bland or active
• Specifically for anterior teeth and gingival retraction