There are several protocols for loading dental implants after surgery based on bone density and healing time requirements. Protocols include Brånemark's loading protocol, progressive loading, and immediate/early loading. The density of the bone where the implant is placed determines the appropriate loading protocol, as less dense bone requires more healing time before loading to allow for sufficient bone mineralization and strength. Progressive loading gradually increases stress on the implant over time to allow the bone to adapt, reducing risks of failure. It is particularly important for lower density bone which is weaker.