Aim To study clinical, radiographic, and microbiological outcomes after non‐surgical therapy of peri‐implantitis with or without adjunctive systemic metronidazole. Materials and Methods A randomized placebo‐controlled clinical trial was carried out in 32 subjects (62 implants) diagnosed with peri‐implantitis. Implants received a mechanical non‐surgical debridement session and systemic metronidazole or placebo. Clinical, radiographic, and microbiological outcomes were evaluated at baseline, 3, 6, and 12 months. Results After 12 months, the test treatment resulted in significantly greater PPD reduction (2.53 vs. 1.02 mm) and CAL gain (2.14 vs. 0.53 mm) (p value <.05) in comparison with placebo. The test treatment also resulted in additional radiographic bone gain (2.33 vs. 1.13 mm) compared with placebo (p value <.05). There was a significantly greater decrease in Porphyromonas gingivalis, Tannerella forsythia, and Campylobacter rectus counts compared with the control group (p value <.05). At the end of follow‐up, 56.3% of patients met the success criteria in the test group and 25% in the control group. Conclusions The use of systemic metronidazole as an adjunct to non‐surgical treatment of peri‐implantitis resulted in significant additional improvements in clinical, radiographic, and microbiological parameters after 12 months of follow‐up. This study is registered in https://clinicaltrials.gov (NCT03564301).

Recent systematic reviews have shown that the survival rate of immediate implant placement is similar to those with a delayed approach. However, preclinical models and human studies have shown that immediate implant placement per se does not preserve the anatomy of the alveolus, mainly at the buccal bone crest, leading to bony dehiscences and subsequently to soft‐tissue recession, with a great impact on esthetic outcomes. On the other hand, preclinical and human studies have identified factors that may prevent bone resorption after immediate implant placement, such as anatomical/biological (alveolus, gingival biotype, periapical/periodontal pathology) and surgical/restorative ones (implant diameter and positioning, flap/flapless, bone and connective tissue grafts, immediate loading/provisionalization, antibiotics). Taking these factors together and with a critical treatment plan made by an expert professional, the immediate treatment approach could be possible and beneficial for the patient.

Regenerative periodontal surgery with a deproteinized bovine bone mineral and a collagen membrane offered additional benefits in terms of radiographic resolution of the intrabony defect and predictability of outcomes with respect to papilla preservation flaps alone.