Objectives: To assess the influence of two barrier membranes and two bone graft substitutes mixed with autogenous bone (AB) on staged guided bone regeneration and osseointegration of titanium implants in dogs. Materials and methods: Four saddle-type defects each were prepared in the upper jaw of six fox hounds and randomly filled with a natural bone mineral (NBM)+AB and a biphasic calcium phosphate (SBC)+AB and allocated to either an in situ gelling polyethylene glycol- (PEG), or a collagen membrane (CM). At 8 weeks, modSLA titanium implants were inserted and left to heal in a submerged position. At 8+2 weeks, dissected blocks were processed for histomorphometrical analysis [e.g., treated area (TA), bone-to-implant contact (BIC)]. Results: Mean TA values (mm2) and BIC values (%) tended to be higher in the PEG groups [TA: NBM+AB (10.42.5); SBC+AB (10.45.8)/ BIC: NBM+AB (86.420.1); SBC+AB (80.121.5)] when compared with the corresponding CM groups [TA: NBM+AB (9.74.8); SBC+AB (7.84.3)/ BIC: NBM+AB (71.320.8); SBC+AB (72.420.3)]. A significant difference was observed for mean TA values in the SBC+AB groups. Conclusion: It was concluded that all augmentation procedures investigated supported bone regeneration and staged osseointegration of modSLA titanium implants. However, the application of PEG may be associated with increased TA values.