This is more than an idea. This is an essential component of ClinicalVision, that mysteriously has been altered with the latest version. One of the main reasons to have a digital computerized periodontal charting system is to facilitate comparison of periodontal data over various time intervals. In the past, I was able to quicktly flick between charts taken at different dates to make these comparisons. Now, however, when a tooth or implant is extracted, all previous charts erase the visible data onscreen related to this tooth or implant. We were told that the data could be retrieved by printing the periodontal tables for prior charting dates, but this greatly inconveniences the ability to make quick comparison between multiple dates. This capability needs to be reestablished on ClinicalVision.