PMC3335612_01
(a) Panoramic radiograph revealing periapical radiolucency in endodontically treated left mandibular premolar, when patient was completely healthy (March 2006). (b) Panoramic radiograph showing dental implants before final restoration. Implants were completely osseointegrated, and no mandibular lesions were observed (September 2006).
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In April 2006, when the patient was completely healthy, he underwent extraction of first left mandibular premolar with failed endodontic treatment (Figure 1(a)) and two intraosseous implants placement in the left mandibular molar region one month after. Dental implants were placed using a two-step process, and, six months after (October 2006), were uncovered and restored, uneventfully (Figure 1(b)). A panoramic radiograph showed a large radiolucency adjacent to the left implant and second left mandibular molar (Figure 1(a)).
(a) Panoramic radiograph showed a large lytic lesion adjacent to the left implant and second left mandibular molar, diagnosed as MM (March 2007). (b) A new panoramic radiograph performed seven months after starting therapy revealed a complete regression of the mandibular lesion, supporting previous diagnosis of mandibular involvement of MM.
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Acid (4 mg/dose, once per month). A new panoramic radiograph performed seven months after starting therapy revealed a complete regression of the mandibular lesion (Figure 2), supporting previous diagnosis of mandibular involvement of MM. 
An extensive area of necrotic bone (arrow) is exposed adjacent to the left implant with purulent discharge (September 2008).
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Intraoral examination revealed that the alveolar bone adjacent to the left implant was exposed with a purulent discharge (Figure 3).
(a) A panoramic radiography showing only low-diffusion radiolucency around the left implant. (b) Computerized tomography image revealing necrotic bone involving left mandibular implant (September 2008).
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The panoramic radiography provided poor diagnostic information, showing only low-diffusion radiolucency in the affected area (Figure 4(a)). Computerized tomography revealed low- and high-density areas in the alveolar process involving left mandibular implant and giving an aspect of necrotic bone (Figure 4(b)).
(a) Exposed necrotic bone around the left implant after three months of antibiotherapy. (b) Image of the resected specimen of bone sequestrum including left implant.
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After 3 months, the pain did not disappear and bone exposure had not reduced (Figure 5(a)). Then, the mobile fragment of exposed necrotic bone including left implant was removed under local anesthesia (Figure 5(b)).