Please select the eligibility criteria that correspond to the clinical trial below.
Title: Effect of Three Periodontal Therapies in Current Smokers and Non-Smokers
Brief Summary: The purpose of this study is to determine in current and non-smokers the clinical and microbiological effects of 3 therapies: scaling and root planing (SRP) alone; SRP in combination with the orally administered antibiotic metronidazole; and SRP with the orally administered antibiotics metronidazole and amoxicillin along with the locally delivered antibiotic doxycycline at periodontal pockets \>= 4 mm.


Options:
A: Inclusion Criteria:

* 18 years of age and up
* clinical and radiographic signs of severe (CAL 5 mm or more) chronic periodontitis.
* at least 20 natural teeth in situ
* pocket probing depths (PPDs) of ≥ 5 mm at a minimum of eight tooth sites
* willingness to participate and to be available at all times required for participation
* over 30% of the teeth present must have a PPDs)≥ 4 mm and insertion loss ≥ 5 mm evaluated by an experienced periodontist
* informed consent signed by the patient

Exclusion Criteria:

* if they (or parents or siblings) show confirmed or assumed allergies or hyper-sensitive skin reactions against moxifloxacin, ciprofloxacin (or other quinolones 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"
* subjects who have undergone antibiotic therapy three months before the start of the study under interrogation
* 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 pregnant or breastfeeding
B: 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
C: Inclusion Criteria:

* under 30 years old and systemically healthy, with at least 20 teeth present. Be willing to participate in the study which is corroborated by signing the informed consent form.

Commit to attend post-therapeutic controls and stop drinking alcohol during the time of ingestion of antibiotics.

Exclusion Criteria:

* Subjects in whom are contraindicated or with hypersensitivity to quinolones - Subjects who have undergone periodontal, surgical or mechanical antibiotic therapy six months before the start of the study according to interrogation.

Women in pregnancy or lactation, corroborated with previous medical history and medical consultation.
D: 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.

Answer: B