an elastomeric foam composition is useful in dentistry for separating the gingiva from the adjacent teeth , for cleaning , as a pressure pack and wound dressing and as a cushion between dental appliances and the gums of a dental patient . the composition is made from a paste - like system of components which expands at least about 150 % to produce a uniformly fine - grained foam composition having a resistance to compression such that a force of at least about 50 g per square cm . is required to result in 10 % deflection . in a preferred embodiment , the elastomeric foam composition is formed from a system of components which includes silicone fluids , siliceous fillers , crosslinkers , hydrogen , sources and a catalyst , all present in amounts which provide a paste - like consistency before foaming and a resistance to compression after foaming such that 80 g . per square cm . is required to produce a 10 % deflection .