A root canal filling per se does not have a significant negative effect on the marginal periodontium.

Aim: To evaluate the periodontal status of single-rooted endodontically treated teeth (ET), correcting for patient- and tooth-related factors.

Methods: Clinical parameters (BoP,PD,CAL) of 240 ET and 240 contralateral vital teeth (VT), before and after non-surgical periodontal treatment, were extracted retrospectively from the journals of 175 patients. Possible patient-related (age, gender, smoking status) and tooth-related (interproximal restoration, root canal filling's extent, post, tooth type) confounders were tested.