Inclusion Criteria:  Inclusion criteria for part 1 of the study:  Patient age 18 and older Patients that received periodontal regenerative surgical treatment at Barts RLDH from January 2017 to January 2019 with and without the use of any biomaterials, bone graft/substitute and membrane or combinations of those. Available full periodontal examination records after non surgical therapy to serve as a baseline for the study and not beyond 12 months before surgery Available radiographic examination of the tooth treated with surgical regenerative procedure at initial examination or after non surgical therapy to serve as a baseline for the study.  Additional inclusion criteria for part 2:  -Patient able and willing to give informed consent  Exclusion Criteria:  Exclusion criteria for part 1:  All the patients that do not match the inclusion criteria will be excluded from part 1. Patients that received regenerative surgical treatment for the management of gingival recession.  Exclusion criteria for part 2:  Unable or unwilling to give consent Pregnant women