An Unusual Case of Early Dental Implant Failure in an Otherwise-Healthy Patient due to Actinomycosis
Actinomyces species are members of normal oral flora that may give rise to a rare disease—oral actinomycosis. Presented herein is a case of early implant failure associated with actinomycosis in an otherwise healthy 43-year-old female and the treatment adopted after explantation. Clinically, 1 month after the implant placement, the peri-implant soft tissues were hyperplastic and associated with an excessive tissue reaction, bleeding, suppuration, deep probing depth, and implant mobility of #19 and #20 implants. Both implants were removed and all granulomatous tissues were thoroughly debrided. Histopathological examination revealed signs of acute ulcerative inflammatory reaction and Actinomyces colonies. The patient was prescribed short-term oral penicillins. Six months after explantation, the deficient bone was augmented using a combination of absorbable collagen membrane, autogenous block bone, and xenograft. The patient was followed for 1 year; and subsequently, 2 implants were re-inserted at the same positions. The patient was followed and no recurrences were observed. Implant failure due to actinomycosis is an extremely rare condition, and a definitive diagnosis is therefore essential for successful treatment.

Buccal (a) and occlusal (b) preoperative views of the edentulous left lower posterior region immediately after the local anesthesia. Preoperative panoramic radiography (c), and preoperative axial images of #20 (d) and #19 (e) regions.

Buccal view after implant insertion (a) and postoperative panoramic radiographic view (b).

(a, b) Erythematous, soft, and hyperplastic gingival tissues around the healing caps; (c, d) Excessive tissue reaction and growth in the mucosa immediately after explantation; (e, f) large bone defect after implant explantation, (g) granulation tissues and a piece of sequestered bone, (h) clinical view after suturation.

Figure 4. (a) Ulcerative mucosal lesion characterized with acute inflammation and granulation tissue (H&E, x100) (b) purple colored, radial filaments of bacteria representing Actinomyces colonies with accompanying neutrophils at the base of the ulcer (H&E, ×400).
Figure 5. Buccal (a) and occlusal (b) views of early healing period after implant explantation

Six months after implant explantation (a, b) the view of gingival tissues, (c) panoramic radiography and axial images of #20 (d) and #19 (e).

Autogenous bone augmentation procedure: (a, b) intraoperative views; (c) view of the adapted autogenous bone graft, bovine bone xenograft graft, and absorbable collagen membrane on the augmented site; (d) primary flap closure. (e, f) Clinical views of early healing after bone augmentation.

(a) Healthy gingival tissues and no recurrence signs 1 year after augmentation. Panoramic radiograph (b), axial images of #20 (c), and #19 (d) 1 year after augmentation. The view of block graft integration (e, f), intraoperative view after re-entry for re-implant placement.

(a, b) Healthy peri-implant tissues 4 months after second implantation, (c, d) clinical view of prosthetic restoration, and peri-implant tissues 8 months after second implantation. Radiographic view around the implant 4 months (e) and 8 months (f) after second implantation.

13-month follow-up postloading of dental implants, (a, b) clinical view of prosthetic restoration, and peri-implant tissues, (c) panoramic radiography.

Timeline of the treatment protocol.
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