Please assess the completion status of the following clinical trial:

Trial Title: Antimicrobial Therapy as Adjunct to Periodontal Treatment: Effect of Timing

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: CROSSOVER
- Observational Model: None
- Primary Purpose: TREATMENT
- Time Perspective: None
- Masking: TRIPLE
- Phase: PHASE4
- Number of Arms: 2.0

Eligibility Criteria:
Inclusion Criteria:~* Untreated moderate to advanced periodontitis (at least 4 teeth with a probing pocket depth (PD) \>4 mm, clinical attachment loss of at least 2 mm and radiographic evidence of bone loss)~* Presence of at least 12 scorable teeth (not including 3rd molars, teeth with orthodontic appliances, bridges, crowns or implants)~* Aggregatibacter actinomycetemcomitans-positive~Exclusion Criteria:~* Systemic illnesses (i.e. diabetes mellitus, cancer, HIV, bone metabolic diseases or disorders that compromise wound healing, radiation or immunosuppressive therapy)~* Pregnancy or lactation~* Systemic antibiotics taken within the previous two months~* Use of non-steroid anti-inflammatory drugs~* Confirmed or suspected intolerance to 5-nitroimidazole-derivatives or amoxicillin subgingival SRP or surgical periodontal therapy in the last year

- Gender: ALL
- Minimum Age: 25 Years
- Maximum Age: 70 Years
- Healthy Volunteers: f

Study Arms:
- Protocol A (Type: EXPERIMENTAL): Antibiotics (3/d 500 mg metronidazole plus 375 mg amoxicillin for 7 days) during the first, non-surgical phase of periodontal therapy (T1), and placebo during the second, surgical phase (T2)
- Protocol B (Type: ACTIVE_COMPARATOR): Placebo during the first, non-surgical phase of periodontal therapy (T1), and antibiotics (3/d 500 mg metronidazole plus 375 mg amoxicillin for 7 days) during the second, surgical phase (T2)

Based on this trial design, predict the completion outcome and termination type (if applicable).