With American Association of Endodontists credentials and a focus on microsurgical retreatment, Brian T. Quesnell, DDS - Mission Hills Endodontics handles operating-microscope-magnified root canal therapy and 3D cone-beam CT-guided diagnosis from the Mission Hills group practice at 1000 W Washington St #2 in 92103. Cases where the tooth is unrestorable or the apex is fractured beyond retreatment are referred for surgical extraction and bone preservation to Center for Oral & Facial Surgery before any implant planning begins. Apicoectomy (root-end resection) microsurgery is performed in-chair when conventional retreatment cannot resolve a periapical lesion. General-dentist referrals from corridor practices including 3rd Avenue Complete Family Dental account for the bulk of new patient flow on the Mission Hills side of the corridor. Same-day emergency endodontic appointments are accommodated for acute irreversible pulpitis, with nitrous oxide analgesia available in addition to local anesthesia. The most demanding cases are microsurgical apicoectomies on previously root-canalled molars where calcified canal anatomy and curved apical roots prevent nonsurgical retreatment from reaching the infection.