## 2 Case Descriptions
### Case 1  
A 73-year-old male was referred due to stage 3 MRONJ of the lower right quadrant, refractory to all previous conservative and surgical therapies. He complained of pain located in the right hemimandible and halitosis. Any signs of hypoesthesia or paresthesia in the maxillofacial region were denied. The patient did not present with a history of head and neck radiotherapy, nor oncological disease. The cause of MRONJ onset was infection and periodontal disease. The patient had a history of hypertension and severe osteoporosis and had previously been medicated with bisphosphonates for a total of six years--three years of yearly intravenouszolendronic acid and three additional years of weekly alendronic acid taken orally. Both drugs were stopped three years before referral. At the moment of referral, an intraoral fistulous tract that probed to bone was noted over the edentulous area of the lower right quadrant, with purulent drainage (Figure 1a). No extraoral fistulae were present. Orthopantomography (OPG) and Computed Tomography (CT) scans revealed a lytic lesion of approximately 30 mm (maximum width) located in the right mandibular body, with the apparent formation of bone sequestrum and the involvement of the inferior alveolar canal (Figure 1b,c). According to the American Association of Oral and Maxillofacial Surgeons (AAOMS) criteria, the patient was diagnosed with stage 3 MRONJ [1]. Figure 1: Case 1 (**a**) Preoperative intraoral view: a fistula that probed to bone was observed in the lower right quadrant. (**b**) Preoperative OPG, demonstrating a lytic lesion of approximately 30 mm (maximum width) on the right mandibular body. (**c**) Pre-operative CT scan (coronal view), revealing a lytic lesion in the right mandibular molar area, with bone sequestrum and extension to the mandibular canal and internal cortical plate. (**d**) Virtual surgical planning for the marginal excision of necrotic bone with a CAD/CAM-designed cutting guide and a customized plate for internal fixation. We calculated 6 mm of reminiscent bone after resection surgery. (**e**) Stereolithographic model of the mandible and CAD/CAM reconstruction plate with 80 mm in length, 8 mm in height, and 2.5 mm thick. (**f**) Intraoral view during the fixation of the cutting guide, after incision and mucoperiosteal flap elevation were carried out, exposing the osteonecrotic lesion. (**g**) Intraoral view after internal fixation with customized reconstruction plate. (**h**) Postoperative OFG at 9 months, showing the ideal adaptation of the plate and signs of bone remodeling. (**i**) Postoperative intraoral view, without signs of bone exposure, fistulae, or purulent discharge. (**j**) Postoperative Computerized Tomography scan at one year post-surgery, showing the adaptation of the plate and the absence of fracture. The patient intervention comprised the pre-treatment phase (VSP and CAD/CAM production one month post-referral), the surgical intervention phase (one month after the pre-treatment), and the follow-up phase (one year post-surgery). During the pre-treatment phase, the patient was submitted for a Computerized Tomography scan using 0.5 mm slices as acquisition parameters. The VSP was performed using KLS Martin Individual Patient Solutions software (KLS Martin IPS Service S.L., San Sebastian, Spain) based on the Digital Imaging and Communications in Medicine (DICOM) files (Figure 1d). Virtual planning was supplemented by videoconferences between the surgical and engineering teams. The surgical team designed the osteotomies and cutting guides. The CAD/CAM guidelines regarding cross-sectional material dimensions for the design and manufacture of the customized reconstruction plate were: titanium \"C\" plate design with a length of 80 mm, height of 8 mm, and thickness of 2.5 mm (Figure 1e). Three-dimensional printed stereolithographic models of the mandibles and cutting guides were received, together with the titanium reconstruction plates.