According to most accepted definitions, complex sleep apnea syndrome (CompSAS) is described as an emergence of central apneas in a patient with obstructive sleep apnea (OSA) upon introduction of continuous positive airway pressure therapy (CPAP). We present two patients who developed comparable central apnea activity when treated with either a CPAP device or a mandibular advancement device. As similar findings have been previously documented in patients with OSA treated with maxillofacial surgery or tracheostomy, we propose that the current definition of CompSAS should broaden to include diagnosis of CompSAS in non-PAP-treated patients, who are managed with either a dental appliance or a surgical procedure.