Please assess the completion status of the following clinical trial:

Trial Title: Effect of Postsurgical Systemic Doxycycline After Regenerative Periodontal Therapy

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

Eligibility Criteria:
Inclusion Criteria:~* Adult patients (at least 18 years of age) with moderate to severe periodontal disease (chronic and aggressive periodontitis) to be recruited from the Dept. of Periodontology, Centre for Dental, Oral, and Maxillofacial Medicine, Hospital of the Johann Wolfgang Goethe-University Frankfurt/Main and from the Section of Periodontology, Dept. of Conservative Dentistry, Clinic for Oral, Dental, and Maxillofacial Diseases, University Hospital Heidelberg~* completed initial periodontal treatment consisting of oral hygiene instruction, scaling and root planing under local anesthesia according the concept of full-mouth disinfection and re evaluation of the tissue response and the patient's plaque control 3 months later. Sites with infrabony defects and persisting pockets (PD \> 5 mm and bleeding on probing, BOP) that occur at re evaluation or supportive periodontal treatment (SPT) are subjected to surgical therapy.~* at least one radiographically detectable infrabony lesion~* good physical health and with effective individual plaque control (Full-mouth-plaque score PCR \</= 30% \[O'Leary et al. 1972\])~* interproximal angular defects on single-rooted teeth or multi-rooted teeth without furcation involvement, radiographic infrabony component \>/= 4 mm, vertical clinical attachment loss (CAL-V) \> 6 mm and PPD \>/= 6 mm~* Only women in childbearing age (\< 45 years) who provide contraception from screening to U2~* informed written consent~Exclusion Criteria:~* known allergies to tetracyclines or any components of the active drug or placebo~* severe liver dysfunction~* local or systemic antibiotic treatment during the last 3 months before surgery~* ineffective individual plaque control (PCR \> 30%)~* kidney dysfunction~* medication with barbiturate, carbamazepin, diphenyhydantoine, sulfonyl-urea, methoxyflurane, ciclosporin A, theophylline, isotretionin~* chronic alcohol abuse~* anticoagulative therapy~* need for antibiotic endocarditis prophylaxis~* pregnancy~* lactation

- Gender: ALL
- Minimum Age: 18 Years
- Maximum Age: None
- Healthy Volunteers: f

Study Arms:
- doxycycline (Type: EXPERIMENTAL): The patients of the doxycycline group will take 200 mg doxycycline once a day for 7 days after regenerative therapy of an infrabony defects~* modified/simplified papilla preservation flap; scaling~* Prefgel/Emdogain~* 0.12% chlorhexidine gluconate solution~* Ibuprofen 400 mg (if necessary)~* 1% chlorhexidine gluconate gel (if necessary)
- placebo (Type: PLACEBO_COMPARATOR): The patients of the control group will take placebo once a day for 7 days after regenerative therapy of an infrabony defect~* modified/simplified papilla preservation flap; scaling~* Prefgel/Emdogain~* 0.12% chlorhexidine gluconate solution~* Ibuprofen 400 mg (if necessary)~* 1% chlorhexidine gluconate gel (if necessary)

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