Local and systemic tissue response submitted to injection of 2 and 30% polymethylmethacrylate in rats' tongue.

Introduction: Adverse effects on the oral mucosa after the use of dermal fillers have been reported due to their increased use for facial aesthetics.

Objective: This study aimed to evaluate, clinically and histologically, the local and systemic effects of two concentrations of polymethylmethacrylate (PMMA) dermal filler in rats.

Material And Methods: Fifty-four female rats were allocated into three treatment groups (2% PMMA, 30% PMMA and 0.9% NaCl), according to the substance injected in the tongue, and three experimental periods: 7, 60 and 90 days. The rats were clinically evaluated and then euthanised, and their tongue and right kidney removed. The histological sections were stained with haematoxylin/eosin and picrosirius.

Results: Clinically, significant differences were found between test groups as to the occurrence of nodules (Kruskal-Wallis; p < 0.001). Histologically, there was greater inflammatory response in the PMMA compared with control (Kruskal-Wallis; p < 0.001). 30% PMMA had greater collagen formation (anova mixed models; p < 0.01). No migration of the material towards kidney was found.

Conclusion: Polymethylmethacrylate induced intense reaction in the initial period of observation (7 days), followed by gradual decrease during the study, favouring the presence of fibroplasia adjacent to the material.