PA surgery maxillary premolar Flashcards
What are some advantages of using cone beam‐ computed technology (CBCT) during surgery?
CBCT offers a great surgical guide for root end procedures. By knowing the correct location of the root end, lesion size, anatomy of tooth, and distance to important anatomical landmarks, the clinician can avoid procedural mishaps and accomplish a complete and predictable surgical seal of the root end. In a study that compared anatomic landmarks using CBCT imaging and periapical radiographs (PRs) before apical surgery, the distance from the lower molars to the mandibular canal could be measured only in 24 of the 64 PR radiographs analyzed (Venskutonis et al. 2014). Furthermore, there have been reports that in 70% of cases, CBCT imaging revealed clinically relevant information that was missed by PRs, and bone defects measured on PRs were approximately 10% smaller than on CBCT images (Christiansen et al. 2009). Studies also have shown that of 58 detected PA lesions, 15 (25.9%) lesions diagnosed with sagittal CBCT slices were missed with PA radiography (Bornstein et al. 2011).
What are some differences between traditional and modern microsurgery?
Endodontic microsurgery combines magnification and illumination provided by the microscope with the proper use of new microinstruments (Kim & Kratchman 2006). With these new advantages, predictability and precision have increased.The advantages of microsurgery include easier identification of root apices, smaller osteotomies and shallower resection angles that conserve cortical bone and root length. In addition, a resected root surface under high magnification and illumination readily reveals anatomical details such as isthmuses, canal fins, microfractures, and lateral canals. Combined with the microscope, the ultrasonic instrument permits conservative, coaxial root‐end preparations and precise root‐end fillings that satisfy the requirements for mechanical and biological principles of endodontic surgery (Kim & Kratchman 2006). SeeTable 19.1 for a brief summary.
What is the appropriate management of soft tissue?
Previous popular flap designs, such as the semilunar design in the anterior region, are no longer recommended because of scar formation and lack of proper access to root end (Kim & Kratchman 2006). Today, esthetics play a crucial role, and the practitioner must minimize any scar formation or recession, when feasible. With modern techniques, flap designs are very similar to those of the traditional techniques: the sulcular full‐thickness flap, the muco‐gingival flap, and vertical releasing incisions. The once popular semilunar flap design and the Lüebke‐Ochsenbein flap design are no longer recommended. In both the sulcular full‐thickness flap and the muco‐gingival flap designs, the wider base of the flap to improve microcirculatory perfusion was an unnecessary procedure, and it created a lasting scar as a result of cutting the mucosal tissue across the fiber lines. With the current method the base of the flap is as wide as the top, and the vertical incisions follow the vertical blood vessel alignment.This facilitates nearly scar‐free healing while still providing more than adequate access to the surgical site. It has been customary to remove 4‐0 silk sutures after one week. With the microsurgery technique, monofilament sutures are removed within 48 to 72 hours for best results.This is enough time for reattachment to take place and the suture removal is easy and painless. After 72 hours, the tissues tend to grow over the sutures, especially with mucosal tissues, and thus removal of sutures may be more uncomfortable (Kim & Kratchman 2006).
How much root resection is needed and why?
Studies that evaluate the root apex show that at least 3 mm of the root‐end must be removed to reduce 98% of the apical ramifications and 93% of the lateral canals (Kim, Pecora & Rubinstein 2001). As these percentages are very similar at 4 mm from the apex, they recommend root‐end amputation of 3 mm, since this leaves 7–9 mm of the root on aver- age, providing sufficient strength and stability. A
root‐end amputation of less than 3 mm most likely does not remove all of the lateral canals and apical ramifications, therefore posing a risk of reinfection and eventual failure (Kim et al. 2001).
What types of isthmuses are seen during root end surgery?
Five different types of isthmuses have been described.
Type I was defined as either two or three canals with no noticeable communication.
Type II exhibited two canals that had a definite connection between the two main canals.
Type III differed from the latter only in that there were three canals instead of two. Incomplete C‐shapes with three canals were also included in this category.
When canals extended into the isthmus area, this was named TypeIV.
TypeV was recognized as a true connection or corridor throughout the section (Hsu & Kim 1997).
