Time line analysis of dental restorative procedures related to dynamic instrument location.
The detailed timing and recording of the sequence of tasks for dental restorative procedures was used to evaluate the effects of the location of the hand-piece and three-way syringe on the dental team performance. Sixty-four audiovisual tapes of ten dental teams, performing complete, actual restorative procedures, were made in two dental operatories that differed only in the location of the dentist's instrument cabinet. Total treatment sessions were divided into four major divisions and expressed as a percentage of the total time: patient preparation, 14%; tooth preparation, 32%; tooth restoration, 50%; and patient release, 4%. Tooth preparation and restoration took longer with the instruments in the 8-o'clock location than with them in the 12-o'clock location. When the teams were reversed, that is, changed to the other operatory, there was an increase in tooth preparation and restoration time. Instrument transfer and use, especially for the three-way syringe, tended to take longer for the 8-o'clock location. In contrast, the dentist's idle time tended to increase working with the 12-o'clock instrument location because of differences in work loads. Time line analysis provided a means of evaluating the impact of instrument location as well as an approach to assessing individual team performance.