Abstract: It is related to an operatory field barrier used in Dentistry, consisting of a rubber dam with a special design simulating either the left or the right side of the oral environment so that it can be used in both sides of the patients' mouth including their superior and inferior teeth (dental arch), their antagonists up to the canines or pre-molars from the opposite side having along their oclusal surfaces convexities related to the dental crowns of that teeth as well as the partial and total reproductions of their bucal sulcus (superior and inferior), the lingual sulcus (inferior) and or the palate (superior) respectively. The product contains borders that will always be outside the mouth completing its elliptical or square or rectangular shape a little bit bigger that the open mouth and these limits have a thicker rubber as an alternative instead of using the conventional frame.