Preparing guide planes for removable partial dentures.

The freehand technique for preparing parallel guide planes offers several advantages. There is a direct transfer of the index from the surveyor to the mouth. The procedure adds little time to routine removable partial denture construction. The method is effective. The only disadvantage of the method is the inability of the dentist to clinically establish perfect parallelism. An occlusal divergence of 3 to 4 degrees from absolute parallelism may result. Care in making the index and increased skill will reduce inaccuracies.