Apical Peri-Implantitis: Possible Predisposing Factors, Case Reports, and Surgical Treatment Suggestions Christer Dahlin, DDS, PhD;* †‡ Hossein Nikfarid, DDS;* Bengt Alsén, DDS;* Hossein Kashani, DDS, PhD* ABSTRACT Background: Apical peri-implantitis is often diagnosed by clinical findings such as pain, redness, tenderness, swelling, and sometimes the presence of a fistulous tract. There are few theories about how such a lesion occurs. Hence, the current clinical treatment protocols are scanty. Purpose: The aim of this report was to evaluate and confer a more extended surgical protocol and to discuss possible predisposing factors for the development of retrograde peri-implantitis. Materials and Methods: Two patients were extensively evaluated with regard to clinical signs, implant treatment, post- operative complications, and surgical treatment. The surgical protocol comprised debridement, with the additional removal of the apical portion of the affected implant. Postoperative checkup included clinical examination and radio- graphs. The follow-up period ranged from 1 to 3 years following surgical debridement. The possible predisposing factors are also discussed in the article. Results: Both cases healed uneventfully with no further symptoms. Radiographs revealed complete bone fill into the resected area and continuous stable bone levels around the previously affected implants. Conclusions: It is concluded that recommendations for treatment of apical peri-implantitis are still minimal. In the present study, a surgical approach with resection of the apical portion of the affected implants in combination with debridement is suggested. Our experience was that partially resected oral implants remain osseointegrated and also function well clinically with a follow-up period up to 3 years. KEY WORDS: implant, implant failure, periapical lesion, peri-implantitis E ndosseous oral implants have successfully been used during the last decades for facilitating the replace- ment of missing teeth in totally or partially edentulous patients. 1–4 Although considered a highly successful treatment modality, concerns have been raised in the literature regarding local infectious conditions in con- junction with oral implants. A more rare site for infec- tion, involving the apical portion of the implants, has been described and named apical peri-implantitis. 5–9 Apical peri-implantitis is often diagnosed by clinical findings such as pain, redness, tenderness, swelling, and sometimes the presence of a fistulous tract. Also, radio- logical findings such as periapical radiolucency around the apical area of the implant can be noted. 10 It should be distinguished from a clinically asymptomatic, peri- apical radiolucency, which is usually caused by implants that are shorter than the drilled implant site or by heat- induced aseptic bone necrosis. 10–12 Inactive lesions only need observation and monitoring. The infected type of lesion can originate from a variety of reasons, such as bacterial contamination during installation, premature loading with subsequent bone microfractures, or the *Department ENT & Oral and Maxillofacial Surgery, NÄL Medical Centre Hospital, Trollhättan, Sweden; † Department of Biomaterials Sciences, Institute for Surgical Sciences, Sahlgrenska Academy Uni- versity of Göteborg, Göteborg, Sweden; ‡ Nicolas & Asp Postgraduate College of Dentistry, Dubai Health Care City, Dubai, United Arab Emirates Reprint requests: Dr. Hossein Kashani, Department of Oral and Max- illofacial Surgery, NÄL Medical Centre Hospital, 461 85 Trollhättan, Sweden; e-mail: hossein.kashani@vgregion.se © 2008, Copyright the Authors Journal Compilation © 2008, Wiley Periodicals, Inc. DOI 10.1111/j.1708-8208.2008.00108.x 222