Objectives No recent study has addressed the effect of diving conditions (pressure increase) on adhesive restorations. We evaluated the impact of a simulated hyperbaric environment on microleakage of the dentine-composite resin interface. The ultimate aim was to propose recommendations for restorative dentistry for patients who are divers to limit barodontalgia (dental pain caused by pressure variations of the environment) and may lead to dangerous sequelae.Methods We bonded 20 dentine disks by using an adhesive system (Scothbond Universal) to ten intact composite cylinders and ten composite cylinders with porosity (Ceram X mono). For each group, the samples were divided into two subgroups, one submitted to a simulated hyperbaric environment and the other to an ambient environment. All samples were immersed in a silver nitrate solution to evaluate microleakage at the interface after analysis with a camera.Results Dye percolation for groups in the hyperbaric environment was greater than groups in ambient environment. For each subgroup, dye percolation was greater for samples with than without porosity.Conclusions High percolation percentages demonstrate that our simulated hyperbaric condition led to loss of sealing at the dentine-composite resin interface, especially with porous composites.Clinical significance Respect of the protocol and the quality of condensation for adhesive restorations are important in all clinical situations, especially for patients who are divers. A more interventionist approach must be adopted with these patients.