Purpose: To review treatment modalities used for pen-implant mucositis and peri-implantitis. Methods: A literature search was performed in PubMed for articles published until May 2013 using peri-implantitis and pen-implant mucositis and different modalities of treatment as search terms. The search was limited to the English literature. Titles and abstracts were searched in order to find studies eligible for the review. Results: The present review reported that treatment of pen-implant mucositis lesions using mechanical therapy is possible. The additional use of professionally delivered antimicrobials has commonly failed to show additional benefits as compared to mechanical debridement alone. The scientific evidence on the efficacy of non-surgical and surgical therapies in the treatment of peri-implantitis is limited. Complete resolution of peri-implantitis using mechanical, laser, or photodynamic therapy does not seem to result in a predictable outcome. Following surgical interventions around implants diagnosed with peri-implantitis, clinical improvements as judged by reductions of probing depths and bleeding on probing have been reported. Bone or bone substitutes have been used in attempts to regenerate bone loss around implants. When regenerative modalities have been employed, radiographic evidence of defect fill has been reported. Few long term follow up studies on the treatment of peri-implantitis are available. Positive treatment results can be maintained over a period of 3-5 years. Regardless of the treatment performed, adequate plaque control by the patient is fundamental to treatment success. If the patient cannot obtain an adequate level of oral hygiene, the infection around the implants will reoccur.