“…Eleven articles were RCTs 14,15,17,18,20,30,31,33,37,38,40 and nine were case series. 16,32,[34][35][36]39,[41][42][43] None of the studies included patients who were smokers. Five articles focused on localized GR defects, 18,36,[38][39][40] three treated both single and multiple GR defects, 15,20,43 and the remaining studies included only multiple GR defects.…”