Apical surgery in mx molars Flashcards
What are the indications and contraindications to apicoectomy in maxillary molars?
Performing an apicoectomy on maxillary molars is indicated when the following circumstances or conditions exist (Merino 2009; Gutmann & Lovdahl 2011a, 2011b):
• Extremely calcified canals due to aging, trauma and large restorations that prevent negotiating the canal to reach the apical foramen.
• Root canal anatomy (such as extremely curved roots) that is impossible to manage non‐surgically.
• An irregular‐shaped apical foramen that prevents a complete seal by non‐surgical procedures such as apical external root resorptions.
• Failure of non‐surgical root canal treatment or persistent apical radiolucencies.
• Reaction to foreign bodies in the periapical tissues such as extrusion of obturation materials beyond the apical foramen.
• Presence of silver cones (Figure 21.5), separated instruments, large/long cast posts or fiber posts (Figure 21.6) which are not retrievable without damaging the root structure.
• Apical transportation, ledges, and zips resulting in root perforations or blockages.
• Post perforations located at the apical third that cannot be treated by non‐surgical techniques.
• Necrotic root fragments in horizontal or oblique
root fractures that are preventing the coronal
fragment from healing.
• Lesions caused by lateral canals at apical third.
• Iatrogenic obstructions
The suggested contraindications to periradicular surgery/apicoectomy on maxillary molars include (Merino 2009; Johnson, Fayad & Witherspoon 2011; Little et al. 2013):
• Medical conditions not allowing surgical intervention such as uncontrolled diabetes and hypertension, alcoholism, IV Bisphosphonates, recent radiation, active infectious oral disease, cancer, or blood disorders.
• Insufficient alveolar bone to support the remaining root structure or poor crown‐to‐root ratio jeopardizing the longevity of the tooth in the long term.
• Significant tooth mobility.
• Non‐restorable remaining tooth structure after
surgery.
• Defective coronal restoration or coronal leakage
as a factor for failure of an endodonic treatment.
• Lack of tooth’s importance in prosthetic plan.
• Poor obturation and good prognosis for successful
retreatment.
• Surgery causing endo–perio defect with difficult
closure.
• Difficult access of the periapical area during
surgery.
• Postoperative care compromised or not
maintainable.
What are the anatomical features in the posterior maxillary region that are considered during radio- graphic evaluation?
The anatomical features in the posterior maxillary region that are considered during radiographic evaluation are as follows (Johnson et al. 2011):
• The proximity of the roots of maxillary molars to
the maxillary sinus.
• Zygomatic process and its radiographic superimposition on surgical area.
• The height and architecture of the alveolar bone.
• The convergence or divergence of the roots of
teeth to be treated and the proximity of roots of
adjacent teeth.
• Presence of lamina dura and periodontal ligament
space.
• Length of roots to be treated.
• Tuberosity.
Is cone beam‐computed tomography (CBCT) recommended as an additional tool for planning of periradicular surgery of maxillary molars?
CBCT may play an important role in planning for surgical endodontic re‐treatment on the palatal roots of the maxillary 1st molar (Rigolone et al. 2003). CBCT allows the clinician to calculate the distance between the cortical plate and the palatal root apex, and to discern the presence or absence of the maxillary sinus between the roots in maxillary molars (Patel et al. 2016; Figure 21.7). Root morphol- ogy, bony topography, existing buccal alveolar bone perforations or fenestrations, and the inclination of roots of teeth planned for surgical intervention can be analyzed and assessed precisely (Nakata et al.
2006; Lofthag‐Hansen et al. 2007; Low et al. 2008). CBCT may also aid in the localization of overex- tended root canal obturation materials, and the localization of perforations and root resorptions. It has been shown that 34% of periapical lesions detected by CBCT were not detected with periapical radiographs.The likelihood of detecting periapical lesions with periapical radiographs was reduced when the root apices were in close proximity to the floor of the maxillary sinus and when there was less than 1 mm of bone between the periapical lesion and the sinus floor.Therefore, CBCT is more sensi- tive for detecting periapical lesions associated with maxillary molar teeth (Low et al. 2008). In general, the information obtained from a CBCT scan in complex anatomic cases may influence the treat- ment plan and the treatment outcome (Ee, Fayad & Johnson 2014). Use of CBCT may also prevent procedural errors such as perforations to the maxil- lary sinus, thus improving the management of apicoectomy of roots of maxillary molars. However, CBCT should only be considered when conventional radiographic techniques do not provide adequate information for the diagnosis and management of endodontic problems (Patel et al. 2015).
What is the best apical bevel of roots undergoing apicoectomy?
Once the apex is exposed, the apical bevel is prepared so that the canal is visible and centered in the beveled surface. Since 98% of apical canal anomalies and 93% of lateral canals exist in the apical 3 mm, it is important to resect at least 3 mm of the root end (Gutmann & Pitt Ford 1993; Stropko, Doyon & Gutmann 2005). However, if a dye discloses the presence of an accessory canal, a greater length of root must be removed (Roy & Chandler 2007). An ideal bevel would be close to perpendicular to the long axis of the root, in order to decrease dentin tubules peripheral microfiltration (Gilheany, Figdor &Tyas 1994); often 30° or 45° bevels are needed for better access and visualization without compromising tooth structure. If the bevel is too great, there is a spatial disorientation that is difficult to overcome and the root‐end preparation and retrofill may fall short of ideal.The smallest bevel possible is favorable, but for posterior teeth, because of anatomy, changes in bevel are inevitable. Once the root has been resected, it should be carefully examined for cracks or fractures as well as for the presence of isthmuses, fins, and anastomoses. These anatomic variations will then dictate the extension of the resection or beveling of the root end (Gutmann & Pitt Ford 1993; Stropko et al. 2005; Gutmann & Lovdahl 2011a).
What is the best approach when the Schneiderian membrane of maxillary sinus is exposed or perforated during periradicular surgery/ apicoectomy
In an event of perforation of the Schneiderian membrane, a resorbable membrane can be placed against the membrane and over the perforated area. If the perforation is small, which is usually the case during apicoectomy, repair may not be needed as long as the Schneiderian membrane “folds over itself” (Fugazzotto & Vlassis 2003).
