Rahman NA, et al. - Researchers performed this retrospective cohort study of patients treated regeneratively in at least one infrabony defect in order to appraise the stability of attachment achieved in infrabony defects by regenerative treatment over 60 ± 12 months compared to control teeth. They included 27 patients (age 58 ± 11.7 years; 12 females, five smokers), each contributing one infrabony defect and one control tooth. In infrabony defects, regenerative therapy provided vertical probing attachment level [PAL-V] as stable over 5 years as periodontally reduced but gingivally healthy or gingivitis sites. Attachment loss was noted in correlation to smoking and periodontitis recurrence.