Method and apparatus for preparing denture

A method of obtaining a gum impression of a patient's mouth and measuring jaw relations using a dental impression tray assembly comprising a lower tray and an upper tray to fabricate a denture, the upper tray comprising a first piece and a second piece and the lower tray comprising a third piece and a pair of fourth pieces, the method comprising:

• loading a first impression material on the lower tray comprising the third piece and the pair of fourth pieces;
• inserting the lower tray comprising the third piece and the pair of fourth pieces and loaded with the first impression material into the patient's mouth to take a lower impression;
• taking out the lower tray from the patient's mouth and cutting the first impression material on the lower tray proximate to a borderline between the third piece and the pair of fourth pieces such that the taken lower impression is divided into a first impression corresponding to the third piece, a second impression corresponding to one of the pair of fourth pieces, and a third impression corresponding to the other one of the pair of fourth pieces;
• separating the third piece from the pair of fourth pieces such that the first impression is retained on the separated third piece and the second impression and the third impression are retained on the separated pair of fourth pieces;
• loading a second impression material on the upper tray comprising the first piece and the second piece;
• inserting the upper tray comprising the first piece and the second piece and loaded with the second impression material into the patient's mouth to take an upper impression;
• taking out the upper tray from the patient's mouth and cutting the second impression material on the upper tray proximate to a borderline between the first piece and the second piece such that the taken upper impression is divided into a fourth impression corresponding to the first piece, a fifth impression corresponding to the second piece;
• separating the first piece from the second piece such that the fourth impression is retained on the separated first piece and the fifth impression is retained on the separated second piece;
• attaching an intra-oral tracer to the separated third piece of the lower tray, the intra-oral tracer comprising an adjustable member that is inserted into a hole formed on the intra-oral tracer;
• inserting the third piece to which the intra-oral tracer is attached and the separated first piece into the patient's mouth together to measure the jaw relations;
• adjusting the adjusting member by raising or lowering the adjusting member to determine a vertical dimension and to adjust a size of a gap between the third piece and the first piece;
• filling the gap with a bite registration material;
• and
• removing the entire piece including the third piece, first piece, and intra-oral tracer from the patient's mouth when the bite registration material is set at the gap.