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:

* ≥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.
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:

1. diagnosis of GAgP (AAP, 1999);
2. presence of ≥20 teeth;
3. presence of ≥ 6 sites presenting PD ≥ 5mm with bleeding on probing (BOP) and ≥2 sites with PD ≥7mm (including incisors and first molars, in addition to other two non-contiguous teeth);
4. good general health;
5. ≤ 35 years old; and
6. agree to participate in the study and sign a written informed consent. All subjects will be individually informed about the objectives, probable risks and benefits of the protocol treatment (according to Resolution nº196 of October 1996 and to the Professional Code of Dental Ethics - 179/93).

Exclusion Criteria:

1. pregnancy or lactating;
2. suffer from any systemic disease (e.g. cardiovascular disorders, diabetes, blood dyscrasias, immunodeficiency, etc) which could alter the course of periodontal disease;
3. took antimicrobials in the previous 6 months;
4. taking long-term anti-inflammatory drugs;
5. previous periodontal treatment within the last 12 months;
6. smokers.
D: Inclusion Criteria:

* diagnosis of Generalized Aggressive Periodontitis
* presence of ≥20 teeth
* presence of ≥ 6 sites presenting probing depth (PD) ≥5mm with bleeding on probing (BOP) and ≥2 sites with PD ≥7mm (including incisors and first molars, in addition to two other non-contiguous teeth between them)
* good general health
* \<35 years of age
* agree to participate in the study and sign a written consent

Exclusion Criteria:

* pregnant or lactating
* suffering from any other systemic disease (e.g. cardiovascular, diabetes, blood dyscrasias, immunodeficiency, etc) which could alter the course of periodontal disease
* received antimicrobials in the previous 6 months
* taking long-term anti-inflammatory drugs
* received a course of periodontal treatment within the last 12 months
* smoked

Answer: B