Abstract
Background: The treatment outcome of nasolabial wrinkles or folds (NF) is widely considered a strong criterion for estimating the overall aesthetic results of different types of hyaluronic acid (HA) injectable fillers. These fillers have undergone various modifications and are classified as monophasic or biphasic, with monophasic fillers further divided into monodensified or polydensified. Objectives: This split-face study aimed to compare the effectiveness and safety of two monophasic HA fillers. Methods: A total of 15 facial aesthetic patients (mean age: 52.4 ± 9.39 years) participated in a split-face study to assess the clinical efficacy, long-lasting effect, and overall skin reaction of two different HA injectable fillers for nasolabial wrinkles. The right NF of each patient was treated with a monophasic, polydensified HA filler; however, the left NF was treated with a scientifically modified monophasic monodensified counterpart. The injection technique and HA quantity injected were consistent. The outcome was assessed using both the Wrinkle Severity Rating Scale (WSRS) and the Global Aesthetic Improvement Scale (GAIS) with analysis of variance (ANOVA) statistical methods. Additionally, the post-treatment naturalness feeling was measured using the FACE-Q questionnaire. Baseline photos were taken in standardized settings, and follow-up visits were conducted at the 1st, 6th, and 12th months. Results: Both HA injectables demonstrated similar effectiveness in terms of aesthetic outcome and long-lasting effect, as interpreted from WSRS and GAIS findings. However, the monodensified HA product received better subjective ratings for naturalness, as indicated by the FACE-Q questionnaire (P < 0.05). Conclusions: Although there were no obvious signs of skin irregularity in both treated wrinkles, patients reported a feeling of intracutaneous tension in the right NF (treated with polydensified HA) but not in the left NF (treated with monodensified HA). Although some subjectivity exists in patient responses, the unanimous preference for the monodensified product due to its natural feeling provides strong support for its use in everyday aesthetic clinical practice.