Please select the eligibility criteria that correspond to the clinical trial below.
Title: Impact of Different Dosages and Time of Administration of Metronidazole and Amoxicillin in the Treatment of Generalized Chronic Periodontitis: A Randomized Clinical Trial
Brief Summary: The aim of this study was to compare the clinical and microbiological outcomes of different dosages of metronidazole (MTZ) and of the duration of the systemic administration of MTZ and amoxicillin as adjunct to scaling and root planing (SRP) in the treatment of generalized chronic periodontitis (GChP).


Options:
A: Inclusion Criteria:

* periodontal screening index (PSI) of IV in at least one sextant;
* range from 18 to 75 years of age;
* clinical and radiographic signs of moderate (clinical attachment loss \[CAL\] of 3 to 4 mm) to severe (CAL 5 mm or more) chronic or aggressive periodontitis;
* at least 10 natural teeth in situ;
* pocket probing depths (PPDs) of ≥ 6 mm at a minimum of four teeth;
* willingness to participate and to be available at all times required for participation;
* willingness to abstain from using antimicrobial mouth-rinses during the study except for those explicitly prescribed;
* informed consent signed by the patient;
* sufficient knowledge of German language.

Exclusion Criteria:

* if they (or parents or siblings) show confirmed or assumed allergies or hyper-sensitive skin reactions against amoxicillin (or other penicillins or other ingredients of Amoxicillin-ratiopharm® 500mg as listed in the "summary of product characteristics, Version Juli 2005"), metronidazole (or other 5-nitroimidazoles and ingredients of Flagyl® 400mg as listed in the "summary of product characteristics, Version Juli 2007"), systemic diseases or conditions as listed in the above mentioned "summary of product characteristics", or show confirmed lactose intolerance;
* have Down's syndrome;
* known AIDS/HIV;
* regularly take systemic medication affecting the periodontal conditions, e.g. phenytoin, nifedipine, and/or steroid drugs;
* professional periodontal therapy during 6 months prior to baseline;
* require antibiotic treatment for dental appointments;
* are undergoing or require extensive dental or orthodontic treatment;
* are pregnant or breastfeeding;
* have rampant caries;
* any oral or extraoral piercing in or around the oral cavity with ornaments or accessory jewelry;
* are dental students or dental professionals;
* have participated in a clinical dental trial in the six months preceding the study;
* cognitive deficits.
B: Inclusion Criteria:

* ≥30 years of age;
* at least 15 teeth (excluding third molars and teeth with advanced decay indicated for extraction)
* a minimum of 6 teeth with at least one site each with probing depth (PD) and clinical \* attachment level (CAL) ≥5 mm;
* at least 30% of the sites with PD and CAL ≥4 mm and bleeding on probing (BOP).

Exclusion Criteria:

* pregnancy
* breastfeeding
* current smoking and former smoking within the past 5 years;
* systemic diseases that could affect the progression of periodontitis (e.g. diabetes, immunological disorders, osteoporosis);
* scaling and root planing an in the previous 12 months;
* antibiotic therapy in the previous 6 months;
* long-term intake of anti-inflammatory medications;
* need for antibiotic pre-medication for routine dental therapy;
* allergy to metronidazole and/or amoxicillin.
C: Inclusion Criteria:

* ≥35 years of age;
* at least 15 teeth (excluding third molars and teeth with advanced decay indicated for extraction);
* a minimum of 6 teeth with at least one site each with probing depth (PD) and clinical attachment level (CAL) ≥5 mm;
* at least 30% of the sites with PD and CAL ≥4 mm and bleeding on probing (BOP).

Exclusion Criteria:

* pregnancy;
* breastfeeding;
* current smoking and former smoking within the past 5 years;
* systemic diseases that could affect the progression of periodontitis (e.g. diabetes, immunological disorders, osteoporosis);
* scaling and root planing an in the previous 6 months;
* antibiotic therapy in the previous 6 months;
* long-term intake of anti-inflammatory medications;
* need for antibiotic pre-medication for routine dental therapy;
* use of orthodontic appliances;
* extensive dental prosthetic rehabilitation;
* allergy to metronidazole and/or amoxicillin.
D: Inclusion Criteria:

* \> 20 teeth
* \> 5% sites (approx. 8 sites) with pocket depth \> 4 mm and / or 5% sites with attachment level \> 4 mm and mean AL \< 4.5 mm and mean PD \< 3.9 mm (not including tooth brush abrasions).

Exclusion Criteria:

* \> 50% of sites with pocket depth or attachment level \> 4 mm
* Pregnancy or nursing
* Periodontal or antibiotic therapy in the previous 6 months
* Any systemic condition which might influence the course of periodontal disease or treatment (e.g. diabetes, AIDS)
* Any systemic condition which requires antibiotic coverage for routine periodontal procedures (e.g. heart conditions, joint replacements etc.)
* Liver disease
* Any known allergy to amoxicillin, metronidazole or doxycycline
* Lactose intolerance

Answer: B