System for determining final position of teeth

An apparatus for arranging a computer model of teeth, the apparatus comprising:

• means for generating an archform representing an arrangement of teeth;
• means for placing a plurality of teeth according to the archform;
• means for determining a differential distance for a tooth positioned between at least two neighbors;
• means for moving the tooth according to the differential distance;
• and
• means for generating a plurality of appliances based on the differential distance, wherein said means for generating a plurality of appliances includes means for generating appliances comprising polymeric shells having cavities and wherein the cavities of successive shells have different geometries shaped to receive and resiliently reposition teeth from one arrangement to a successive arrangement.

A computer program product, tangibly stored on a computer-readable medium, for arranging a computer model of teeth, comprising instructions operable to cause a programmable processor to:

• generate an archform representing an arrangement of teeth;
• place a plurality of teeth according to the archform;
• determine a differential distance for a tooth positioned between at least two neighbors;
• move the tooth according to the differential distance;
• and
• generate a plurality of appliances based on the differential distance, wherein the appliances comprise polymeric shells having cavities and wherein the cavities of successive shells have different geometries shaped to receive and resiliently reposition teeth from one arrangement to a successive arrangement.

A system for arranging a computer model of teeth, comprising:

• a processor;
• a display device coupled to the processor;
• and
• a data storage device coupled to the processor, the data storage device storing instructions operable to cause the processor to:
• generate an archform representing an arrangement of the plurality of teeth;
• place a plurality of teeth according to the archform;
• determine a differential distance for a tooth positioned between at least two neighbors;
• move the tooth according to the differential distance;
• repeat the determining and moving steps according to a function of at least one of the differential distances when the sum of differential distances for the plurality of teeth exceeds a predetermined threshold;
• and
• generate a plurality of appliances based on the differential distance, wherein the appliances comprise polymeric shells having cavities and wherein the cavities of successive shells have different geometries shaped to receive and resiliently reposition teeth from one arrangement to a successive arrangement.