Intact Cortical Bone Plate
No clues exist in this situation; so in order to prevent excessive bone removal, a small hole is made in the cortical plate over the apex and filled with a small piece of gutta-percha or lead. Then, a parallel radiograph is taken and proper adjustment is made to make the osteotomy right over the apex of the root.
Making the osteotomy high or low has different consequences for the root and bone capital.
During the osteotomy window creation procedure, all the bone removed is lost. If a bone graft is required for regeneration of the bone defect, a trephine instead of a bur can be used in certain anatomical areas. At the end of surgery this bone can be used, in a piece, to block back the osteotomy window, or particu-lated to cover the denuded root surface.
After the osteotomy window has been made, two different situations can be encountered:
- Difficult When there is no granulation tissue around the apex it is difficult to distinguish the root tip from the surrounding bone. The root is harder, more dark and yellow and does not bleed, and the bone is whiter, softer and bleeds when scraped. Methylene blue and the operating microscope can help to distinguish both: the dye stains the connective tissue of the periodontal ligament that surrounds the root apex (described later in this chapter), and the magnification provided by the operating microscope helps to clearly differentiate both and minimize unnecessary bone removal.
- Easy: When there is granulation tissue around the root tip it is better to remove it first, and then the root end will show up clearly and modifications of the osteotomy window can be made, if necessary, to make the apicoectomy easier.