Microsurgical instruments for root-end cavity preparation following apicoectomy: a literature review.

Root-end cavities have traditionally been prepared by means of small round or inverted cone burs in a micro-handpiece. Since sonically or ultrasonically driven microsurgical retrotips became commercially available in the early 1990s, this new technique of retrograde root canal instrumentation has been established as an essential adjunct in periradicular surgery. At first glance, the most relevant clinical advantages are the enhanced access to root ends in limited working space and the smaller osteotomy required for surgical access because of the various angled designs and small size of the retrotips. However, a number of experimental studies comparing root-end preparations made with microsurgical tips to those made with burs have demonstrated other advantages of this new technique, such as deeper cavities that follow the original path of the root canal more closely. The more centered root-end preparation also lessens the risk of lateral perforation. In addition, the geometry of the retrotip design does not require a beveled root-end resection for surgical access thus decreasing the number of exposed dentinal tubules. A controversial issue of sonic or ultrasonic root-end preparation is the formation of cracks or microfractures, and its implication on healing success. The present paper reviews experimental and clinical studies about the use of microsurgical retrotips in periradicular surgery and discusses many issues raised in previous papers.