Rahman NA, et al. - As compared to control teeth, researchers examined the stability of attachment achieved in infrabony defects by regenerative treatment in 27 subjects between 2004 and 2010. They observed significant attachment gain (2.7±1.6 mm) due to regenerative therapy after 1 and (3.0±2.2 mm) 5 years. They found no significant change of PAL-V from 1 to 5 years subsequent to surgery for regenerative (-0.3±2.4 mm) vs control teeth (-0.2±1.4 mm). They noted an association of smoking and generalized recurrence of periodontitis (amount of sites with PPD > 5 mm) with attachment loss.