In the present study, only two implants in patients with thin gingival biotypes failed to reach the clinically acceptable PES level. All other patients with both thick and thin biotypes achieved either acceptable or almost perfect scores for both PES and WES. According to the results of Angkaew et al., the PES/WES scores of patients with thick gingival biotype were significantly higher than those with thin gingival biotype; although no such correlation was detected in this study [2]. Peri-implant soft tissue stability is reported to be associated with gingival biotype, which is a significant parameter for the esthetic outcome of the implant restoration in the anterior region [19,20,21]. However, the results from the present study demonstrate that the gingival biotype may not necessarily play a very central role on esthetics in single implant restorations. Therefore, the authors of this study believe that patients with thin gingival biotypes may also expect to have acceptable esthetic results for single implants in the anterior maxilla so long as proper surgical and prosthetic protocols are meticulously designed and implemented.

The smile line is an indispensable element of esthetic dentistry and an important consideration of any oral rehabilitation. A recent study by Antoniazzi et al. among Brazilian population reported that patients with high smile lines were significantly less satisfied with their smile compared to those with lower smile lines [22]. Even though their study consisted of patients with natural teeth, the analyses from this study similarly found a significant negative correlation between VAS and the smile line of patients with anterior implant restorations. Accordingly, the patients with low and medium smile lines had similar levels of concerns regarding the esthetic aspects of their implants. However, the patients with high smiles lines and significantly lower VAS scores had worse perceptions than both groups. Therefore, patients with lower smile lines more frequently reported favorable esthetic outcomes. Patients with high smile lines are considered a challenge in attaining esthetic results, since the restoration and the gingival tissues are displayed more than those with lower smile lines, where these elements are hidden behind the upper lip [23, 24]. Thus, smile line evaluation should not be skipped during implant consultations in order to accurately meet patient expectations.