Arcuate dental trays have been used for many years to obtain an accurate impression of a tooth formation or a gum contour preparatory to dental repair, replacement or orthodontia. Often the use of these trays, which must be pressed down in the mouth with considerable pressure, cause patient discomfort. In many cases, this discomfort is caused by the presence of what is termed a growth in the mouth called torus mandibularis, slow growing bony protuberances or exostoses which are found on the lingual surface of the lower jaw or mandible, opposite the bicuspid teeth. These occur bilaterally on both sides of the jaw adjacent to the tongue, most usually on the lingual side, and may vary in size or shape. In some cases, the tori mandibularis is unilateral on one side only.
Whether unilateral or bilateral, when a filled standard impression tray is inserted in the mouth and pressed down to obtain an impression of the teeth in the lower jaw, the lower edges of the standard tray will strike the torus mandibularis and cause considerable discomfort. This may also inhibit proper placement of the tray and interfere with the obtaining of a proper and accurate impression.
It is an object of the present invention to provide a dental impression tray which can be used for patients with or without the torus mandibularis. The trays may be made of perforated metal, hydrocolloid, plastic disposable material or cast metal and may be made in different lengths and widths. The lingual and buccal flanges which pass on each side of the dental arch are modified so that the lingual walls are brought closely together into the center of the mandible and thus avoid direct contact with the tori. The outer buccal walls of the tray will center the tray properly, thus placing the lingual walls in a position to avoid contact with the existing tori.
Other objects and features of the invention will be apparent in the following description and claims in which the principles of the invention are set forth together with details to enable persons skilled in the art to practice the invention, all in connection with the best mode presently contemplated for the invention.