A patient needs an occlusal guard. Which phase of treatment is this?

In the PERIODONTAL TREATMENT SEQUENCE: Phase I = Preliminary/Systemic (emergency, occlusal guard/splint for TMD, controlled systemic conditions). Phase II = Non-surgical (SRP, OHI). Phase III = Surgical (if needed). Phase IV = Maintenance. An OCCLUSAL GUARD for bruxism/parafunctional habits or TMD is placed in the PRELIMINARY PHASE (Phase I) to stabilize the occlusion and control etiological factors BEFORE definitive periodontal treatment begins. A is correct.