Characteristics of the included studies: non-surgical periodontal therapy.

SRP – scaling and root planning, PPD Periodontal probing depth, CAL -clinical attachment level, PD – periodontal disease, MO – microorganisms; BS – blood sample; mm – millimeters; PCR – polymerase chain reaction
Lafaurie [18] - University-based (Colombia) This study was supported by the Instituto Colombiano para la Ciencia y la Tecnologia Francisco Jose de Caldas; Maestre Vera [20] - University-based (Spain); Padilla [21] -University-based (Chile); Forner [17] - University-based (Denmark) This study was supported by the Danish Dental Association, Colgate–Palmolive and the Danish Foundation for Mutual Efforts in Dental Care; Kinane [16] - University- based (United Kingdom), Zhang [55] – University-based (Australia).