Patient KR, a 45-year-old man. (a) The missing lower-right molars were replaced with 2 hollow-screw implants. (b) After 3 years, a bony defect developed around the most posterior implant. (c) Conservative measures (ultrasonic curettage and chlorhexidine irrigation) failed to arrest the lesion's development, which, in 3 months, progressed to the state as shown. At that time, an open-flap debridement and disinfection was performed. (d) Eventually, the lesion healed to about 80% of the original bone level

Patient JL, a 46-year-old woman. (a) A postanchored restoration had been placed about 10 years earlier. Then the mesial root fractured (b) and an implant was placed (c). Within 1 week, the patient developed an acute osteomyelitis, which motivated the removal of the implant after 14 days. (d) The pain subsided rapidly, but the 3-months postoperative exam disclosed a fistula as well as a radiolucency at the site of the former implant. (e, f) The patient was placed on several courses of antibiotics and underwent 2 sessions of surgical bone curettage. (g, h) Finally, the infection subsided and the site healed to near-previous levels

Patient GL, a 78-year-old woman. (a) Nine years after placement of a postanchored restoration, the upper-left lateral incisor developed pain on pressure, indicating a fissure of the root. (b) Five months after the tooth's extraction, a hollow-screw implant was placed, which allowing healing without complications. (c) After 6 months, a bluish coloration of the gingiva was noted and a radiograph revealed a lateral and periapical radiolucency. The implant was painless and clinically functional; hence, the implant was fitted with a provisional crown. However, 2 months after being informed of her situation, the patient elected not to pursue treatment at our office and was lost to follow-up

Patient NU, a 68-year-old woman. (a) An implant was inserted into the mesial root alveolus of a lower-left molar extracted 4 months earlier. (b) After 3 months, the site developed symptomatologies (pain and swelling) and a radiograph disclosed a periapical radiolucency. The site was surgically debrided and disinfected and finally healed. (c) A 1.5-year postoperative radiograph

Patient SA, a 20-year-old man with multiple ageneses. (a) Among other implants, two 3.3-mm diameter implants were placed on each side of the symphysis. (b) After 2 weeks, the site became painful and, radiographically, a 10-mm lacuna had appeared. The patient was placed on antibiotics and the symptoms disappeared. (c) After 5 months, the site had remineralized

Patient GA, a 51-year-old woman. (a) Three implants were placed in the lower-right sextant. (b) At 1-month postoperatively, a radiograph disclosed a radiolucency located midlevel of the root, and the patient remained symptom free. (c) No specific treatment was initiated, and the lesion disappeared spontaneously after 8 months

Patient LE, a 45-year-old man. (a) Three fixtures were anchored into the lower-left molar area and (b) were loaded after 9 months via provisional restorations. (c) After 4 months, an increased mobility of the implants was noted clinically, and signs of loss of osseointegration were apparent. At this point, the provisional splint was altered to provide a 1- to 2-mm clearance. (d) Three months later, the implants had become firm and osseointegration had progressed. (e) After 6 months, the bone had healed close to its initial levels. (f) After 9 months, the patient was fitted with a 3-unit metalceramic restoration and provided with an occlusal splint