Comparison between guided and freehand preparation.

Parallel pin retention is traditional in restorative dentistry and provides a conservative approach to removal of tooth structure, including restorations with supragingival margins. However, the question of whether pinhole preparations should be performed freehand or by using a paralleling instrument has been frequently discussed. This investigation compared the precision of freehand and instrument-guided preparations under simulated clinical conditions. The results indicated that guided preparations provided better paralleling precision than freehand preparations, but did not exclude success by the freehand approach. Both instrument preparation and freehand preparation were influenced by the dentist's dexterity and technical capability.