Clinical tissue response to different concentrations of chlorhexidine applied to hybrid and chitosan-based dermal fillers: An in vivo study

Objective: The study investigated how different chlorhexidine concentrations affect tissue reactions in living animals through an in vivo animal study. Methods: Twelve healthy adult New Zealand white rabbits were allocated into two groups according to filler type: hybrid filler and chitosan-based filler (n = 6 each). The researchers performed subcutaneous injections of dermal fillers and applied chlorhexidine solution at three different strengths of 0.2% and 2.0% and 2.2% to different injection areas. The semi-quantitative inflammation scoring system allowed researchers to evaluate local tissue reactions at three different time points (7, 12 and 20 days post-application). The researchers used appropriate statistical methods to determine which chlorhexidine concentrations and filler materials influenced tissue tolerance. Results: The 0.2% chlorhexidine solution caused brief and slight inflammatory reactions, which occurred in both hybrid and chitosan-based filler materials. The tissue showed increased inflammation at higher concentration levels of 2.0% and 2.2%, which resulted in prolonged skin redness and swelling. The chitosan-based fillers produced higher inflammation scores than hybrid fillers during tests which used identical chlorhexidine concentrations (P < 0.05). Conclusions: The study findings demonstrate that tissue tolerance depends on two main elements, which are chlorhexidine concentration and filler material composition. The 0.2% chlorhexidine solution demonstrates potential for medical applications with hybrid and chitosan-based dermal fillers, but it causes inflammatory responses when used at elevated concentrations, which damages chitosan-based materials. The study results show that dermal filler procedures require individualised antiseptic protocols to achieve the best possible tissue protection.