INTRODUCTION
Over the past two decades, hyaluronic acid (HA) has gradually become the benchmark product for wrinkle-filling and face volumetry.1,2 With the market booming, HA is one of the most in-demand beauty treatments in the United States, Europe, and Asia. Considering this development, many laboratories now manufacture HA for the purposes of beauty treatments. For some years now, several gels benefit from the FDA approval.Others, including the ones presented here, are currently in the process of being registered. Few manufacturers offer more than one range of dermal fillers, meaning that they offer different products with the same indication for use. The rationale behind this is often not very clear since the manufacturers usually avoid to present comparative data between dermal fillers from the different ranges.We have selected two dermal fillers from the same manufacturer based in Geneva, Switzerland, with the same indication for use: “filling of line wrinkles on the face, damaged skin such as mild or moderate nasolabial folds, peribuccal, and glabella wrinkles.” Interestingly, the manufacturer states that both products are made from the same type of high-molecular weight HA crosslinked with butane diglycidyl ether (BDDE). The new product includes less BDDE cross-linker than the previous one. To assess if there was a real advantage of the newer product (RHA 2) compared to the existing range (PS-GA), the two products were submitted to various laboratory tests for cohesivity, resistance to stretching, and spreading, as well as to histology and ultrasound monitoring. In a second part of the article, the personal experience of the first author with the new range of products (RHA 1-4) is described based on the 6-month follow-up of 27 treated patients. Data about PS-GA are subject of a poster.3 This article also acts as a supplement to previously published articles.4-6
MATERIALS
Examined GelsButane diglycidyl ether is the crosslinking agent for both gels. Both are manufactured with 0.3% lidocaine.Teosyal® PureSense Global Action (PS-GA): batch number: TS30L134103C (TEOXANE). The gel was examined in a previous comparative study.4-6 The gel HA concentration is 25 mg/mL. The crosslinking process aims to yield an “homogeneous crosslinking network” (isotropic distribution of crosslinking bridges; Personal communication, S. Meunier, TEOXANE).Teosyal® RHA 2 (RHA 2): batch number: TP30L-143601B (ultrasound monitoring), TP30L-151705B (histological tests). This gel HA concentration is 23 mg/mL. The crosslinking technology aims to minimize the degradation of the hyaluronic acid chains during the manufacturing process and also to reduce the crosslinking degree of HA in the final product (Personal communication, S. Meunier, TEOXANE).Instruments and ProductsFor laboratory testing: Petri dish, jar for urine samples, tape measure, NaCl 0.9% in water (B. Braun), colorant: Royal Talens
