Erratum to: Effects of periodontal treatment on exacerbation frequency and lung function in patients with chronic periodontitis: study protocol of a 1-year randomized controlled trial - Romero, Sergio dos Santos; Pinto, Erika Horácio; Longo, Priscila Larcher; Corso, Simone Dal; Lanza, Fernanda Cordoba; Stelmach, Rafael; Rached, Samia Zahi; Franco, Adriana Lino dos Santos; Mayer, Marcia Pinto Alves; Bussadori, Sandra Kalil; Fernandes, Kristianne Porta Santos; Ferrari, Raquel Agnelli Mesquita; et al. (BMC Pulmonary Medicine, 2017)