PRESS and Piezo Microsurgery (Bony Lid): A 7-Year Evolution in a Residency Program Part 1: Surgeon-defined Site Location

Treatment of a failing endodontic procedure via microsurgical revision presents better outcomes due, in part, to the integration of the surgical operating microscope (SOM) and cone-beam computed tomography (CBCT) into clinical practice. But challenges still remain with respect to the operational locations and the techniques required to address them. Posterior sites, with substantial cortical plate thicknesses and sensitive anatomy, present the dichotomy of visualization versus postsurgical regeneration of bone. The bony lid technique bridges the gap between these 2 concepts, and the application of piezosurgery renders a precise and biocompatible osseous incision. The purpose of this paper was to outline, through case reports, the progression of piezo-guided surgery in a postgraduate resident setting. The primary evolution of the bony lid technique relied on the transfer of measurements from defined landmarks in the CBCT volume to the cortical plate of the surgical site. The secondary evolution used the same measurement protocols transferred to a laboratory model of the patients' arch. A vacuformed stent was fabricated with pertinent fiducial markers in gutta percha defining the surgical site parameters, and a scan exposed with the stent in place. These 2 evolutions are designated as the surgeon-defined site location method and are explained in greater detail in this the first of 2 parts of the topic. All surgeries were executed using the piezosurgical method with increasing levels of guidance and precision throughout the evolution process. Each step in the technique implementation enabled the resident to assimilate a new technique and skill set while maintaining bone architecture and minimizing volume loss postoperatively. The patient benefits were an increase in intraoperative safety and postoperative comfort. The resident benefits were accelerated regeneration timetables, and increase in the confidence level of the resident and number of scheduled posterior surgical procedures. The progression from crude on-site measurements to elegant and precise surgical guides enabled the access and manipulations of difficult surgical sites without compromising visibility, postoperative osseous regeneration, or patient comfort.