A disposable, self-inflatable, matrix (tooth dam) used to form a temporary, removeable side wall for the placement of a tooth filling material. It has an array of three concavities (distal, central and proximal) formed in a polymer wrap that has a planar substrate sheet affixed across the front face of the wrap. The distal air chamber has a volume that equals or exceeds the combined volume of the central and proximal air chambers. Directly below the distal concavity on the inner face of the planar substrate is an adhesive region. When the distal air chamber is depressed, the air within inflates the other air chambers and it is retained in its compressed state by the adhesive region. The remaining air chambers press against one tooth and exert enough force to elastically secure the planar panel around the adjacent tooth. It prevents the tooth filling material from leaving the prepared tooth and entering the space between.