OBJECTIVE: To describe a patient with oro-antral fistula and a literature review. CASE REPORT: A male patient, 43 year-old farmer, residing in Caaguazú, Paraguay, who consulted the department of otolaryngology of the Clinical Hospital of the FCM with a history of seven months of development dental extraction of three teeth contiguous to apical periodontitis chronic suppurative, which began after a pain that radiated the facial region, moreover drainage of purulent nasal cavity and the left area of fistula. CONCLUSION: oro-antral fistula should be treated with the establishment of a physical barrier to prevent maxillary sinus infection. The closing of communications or fistulas with autologous bone graft substitute is a valid alternative to techniques based on REMNANTS. Due to the constant need of rehabilitation with implants and the need for surgical procedures prior to implant such as increase of maxillary sinus; the closing of the usual soft tissue was converted into a major problem.