A dental impression injection tray (10, 10a, 10b, 100, 120, 140, 160, 180) for forming a dental impression of a dental structure (1, 2, 3) includes a tray body (12, 102, 122, 142, 166, 182) defining an impression cavity (14, 103, 123, 149, 168, 184) sized to receive the dental structure. At least one injection port (16, 20, 105, 150, 170, 186) is formed on the tray body and communicates with the impression cavity, and is adapted to direct a supply of impression material into the impression cavity. A plurality of gingival sealing elements (30-36, 30a-36a, 30b-36b, 106-112, 126-132, 154-158, 185, 194, 196) are coupled to the tray body and are adapted to sealingly engage gum surfaces adjacent to the dental structure and block the impression material from escaping the impression cavity during injection of the impression material into the impression cavity. A system (210) for forming a dental impression may include the dental impression injection tray (212), an impression material delivery device (214), and a pressure control mechanism (214, 218, 220) that controls a pressure of the impression material inside of the impression cavity.