Differentiation of NASHA and OBT Hyaluronic Acid Gels According to Strength, Flexibility, and Associated Clinical Significance.

BACKGROUND: With a wide range of hyaluronic acid (HA) filler products available, knowledge of gel characteristics is a key part of tailoring treatments to each patient's aesthetic goals. This paper presents 2 main gel characteristics - strength/firmness and flexibility - for HA fillers produced using NASHA® and OBT™ and their clinical significance for tissue performance. METHODS: Three NASHA gels (Restylane®; Restylane Silk; Restylane Lyft) and 4 OBT gels (Restylane Refyne; Restylane Kysse; Restylane Volyme; Restylane Defyne) were studied in dynamic mode using a PP25 rheometric measuring system at 25 degrees C. Gel strength/firmness was measured using frequency sweep, with G prime evaluated at 0.1 Hz. Flexibility assessments used amplitude sweep measurements between 0.1% and 10,000% strain at 1 Hz, with xStrain being the strain value at the crossover point where G prime and G double prime have the same value.  Results: Restylane, Restylane Silk, and Restylane Lyft had G primes of 701, 416, and 799 Pa, respectively. OBT G primes for Restylane Refyne, Restylane Kysse, Restylane Volyme, and Restylane Defyne were 70, 160, 171, and 271 Pa, respectively. The xStrain values were 1,442% (Restylane Refyne), 908% (Restylane Kysse), 930% (Restylane Volyme), 761% (Restylane Defyne), 7% (Restylane), 19% (Restylane Silk), and 17% (Restylane Lyft).  Conclusions: OBT products had high flexibility (tolerance to deformation) and low to intermediate strength/firmness, which make them appropriate for dynamic facial areas. NASHA products showed greater strength/firmness, with the potential to create lift and projection. Altogether, NASHA and OBT HA gels covered a wide range of strength and flexibility. J Drugs Dermatol. 2024;23(1):1332-1336.     doi:10.36849/JDD.7648.

A randomized, split-face, double-blind, comparative study of the safety and efficacy of small- and large-particle hyaluronic acid fillers for the treatment of nasolabial folds.

BACKGROUND: Injections of hyaluronic acid (HA) for tissue augmentation are one of the most common aesthetic treatments performed worldwide. However, few studies have compared the safety and efficacy of small- and large-particle HA (SP-HA; LP-HA). AIM: To assess and compare the safety and efficacy of SP-HA and LP-HA for the correction of nasolabial folds (NLFs). METHODS: A prospective, split-face, triple-blind study design was used. Ten female subjects were recruited. Patients underwent treatment at baseline, an optional touch up at Week 2, and a follow-up visit at Week 4. At weeks 2 and 4, a blinded reviewer assessed the patients using the Global Aesthetic Improvement Scale (GAIS) and Wrinkle Severity Rating Scale (WSRS); and subjects completed the Patient Satisfaction Questionnaire (PSQ). At all visits, 3-dimensional imagery and ultrasonography of patients' NLFs were captured. Adverse events (AEs) were evaluated by the Investigator and recorded by subjects in diaries. RESULTS: The GAIS response rate, defined as ≥ "improved" from baseline, was between 90 (2 weeks) and 100% (1 month) for SP-HA and was 100% for LP-HA, at both visits. Paired-samples t tests revealed significant differences in the change in WSRS scores between groups, at both visits (P < .01). Differences in the clinical effect and lifting capacity of both products were observed in 3-dimensional imagery and ultrasonography. Treatment volumes varied, with 61.32% more SP-HA being required than LP-HA for achieving a ≥ one-grade WSRS improvement. There were no severe AEs throughout the trial, nor AEs related to the investigational device. CONCLUSIONS: LP-HA demonstrates better efficacy for correcting bony resorption in the nasal pyriform region.