DENTAL MODELING METHOD AND APPARATUS USING APERTURED MATRIX PLATE

An improved method and apparatus for making cast dental models having integral dowel pins permitting segments or dies of a model to be attached and re-attached to a base plate in a precise location, by means of holes in the base plate adapted to insertably receive the dowel pins, is disclosed. The apparatus includes a base plate having a generally semi-circular shape, the arcuate outer wall surface of which is modified to have flat walls approximating the shape of a circumscribed polygon. A matrix positioning plate has a polygonal aperture through its thickness dimension adapted to insertably receive the base plate. A negative dental impression is attached to a first, lower surface of the matrix plate, and a transparent transfer plate of the same size and shape as the base plate inserted into the aperture of the matrix plate. Marks are placed at those locations of the transfer plate where dowel pins are desired to engage parts of the dental impression viewed through the transfer plate. The marked transfer plate is then clamped in overlying conformal relationship to a base plate, and holes formed in the base plate at the locations indicated by the marks. In another embodiment of the invention which dispenses with the requirement for a transfer plate, a transparent base plate is inserted into the matrix plate, marked and removed. Holes are then formed in the base plate at the marked locations.