“…Systemically healthy patients were included in every study [ 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. Regarding the inclusion of smokers, six studies excluded smokers [ 32 , 33 , 35 , 37 , 38 , 39 ], one included smokers of less than 10 cigarettes per day [ 36 ] and one included smokers [ 34 ]. Concerning the periodontal status, Al Nashar et al [ 32 ] included patients with chronic periodontitis in the mandibular anterior region, Khan et al [ 35 ] excluded patients with severe periodontal bone loss, and six studies [ 33 , 34 , 36 , 37 , 38 , 39 ] included patients with good oral hygiene.…”