Salian Kiran Kumar Krishanappa, Prashanti Eachempati, Sumanth Kumbargere Nagraj, Naresh Yedthare Shetty, Soe Moe, Himanshi Aggarwal, Rebecca J Mathew

An oro-antral communication is an unnatural opening between the oral cavity and maxillary sinus. When it fails to close spontaneously, it remains patent and is epithelialized to develop into an oro-antral fistula. Various surgical and non-surgical techniques have been used for treating the condition. Surgical procedures include flaps, grafts and other techniques like re-implantation of third molars. Non-surgical techniques include allogenic materials and xenografts. This is an update of a review first published in May 2016. To assess the effectiveness and safety of various interventions for the treatment of oro-antral communications and fistulae due to dental procedures. Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 23 May 2018), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2018, Issue 4), MEDLINE Ovid (1946 to 23 May 2018), and Embase Ovid (1980 to 23 May 2018). The US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. We also searched the reference lists of included and excluded trials for any randomised controlled trials (RCTs). We included RCTs evaluating any intervention for treating oro-antral communications or oro-antral fistulae due to dental procedures. We excluded quasi-RCTs and cross-over trials. We excluded studies on participants who had oro-antral communications, fistulae or both related to Caldwell-Luc procedure or surgical excision of tumours. Two review authors independently selected trials. Two review authors assessed trial risk of bias and extracted data independently. We estimated risk ratios (RR) for dichotomous data, with 95% confidence intervals (CI). We assessed the overall quality of the evidence using the GRADE approach. We included only one study in this review, which compared two surgical interventions: pedicled buccal fat pad flap and buccal flap for the treatment of oro-antral communications. The study involved 20 participants. The risk of bias was unclear. The relevant outcome reported in this trial was successful (complete) closure of oro-antral communication.The quality of the evidence for the primary outcome was very low. The study did not find evidence of a difference between interventions for the successful (complete) closure of an oro-antral communication (RR 1.00, 95% Cl 0.83 to 1.20) one month after the surgery. All oro-antral communications in both groups were successfully closed so there were no adverse effects due to treatment failure.We did not find trials evaluating any other intervention for treating oro-antral communications or fistulae due to dental procedures. We found very low quality evidence from a single small study that compared pedicled buccal fat pad and buccal flap. The evidence was insufficient to judge whether there is a difference in the effectiveness of these interventions as all oro-antral communications in the study were successfully closed by one month after surgery. Large, well-conducted RCTs investigating different interventions for the treatment of oro-antral communications and fistulae caused by dental procedures are needed to inform clinical practice.