Test conditions applied. Test conditions applied for each implant (green arrows indicate the possible leakage paths): A) abutment manual screwing. Nitrogen flow may occur at both gaps: between screw and abutment and between abutment and implant collar (assay 1). B) screw hole blocked with wax; manual (assay 2) or key (assay 3) screwing. C) abutment key screwing, screw hole and implant to abutment connection blocked with wax (as a negative test).