Quantifying adhesive residue on skin: a randomized pilot in vivo comparison of five maxillofacial prosthetic adhesives and their failure modes

Maxillofacial prosthetic adhesives are widely used for retention, but their removal can result in adhesive residue on the skin, contributing to patient burden and potential skin injury. Despite its clinical relevance, adhesive residue has not been quantitatively evaluated in vivo. This study aimed to assess and compare adhesive residue according to adhesive type and to infer the predominant failure mode from the observed residue pattern. A randomized, double-blind experimental in vivo study was conducted on 30 skin sites across 5 healthy volunteers ( n = 6 sites per adhesive group). As this was an exploratory pilot study intended to generate preliminary effect size estimates and feasibility data, a formal a priori sample size calculation was not performed. Five commercially available maxillofacial adhesives, including two silicone-based adhesives (SBAs) and three water-based adhesives (WBAs), were applied to standardized silicone elastomer strips on the volar forearm. After 8 h of functional wear, the strips were removed, and the mass of adhesive residue remaining on the skin was quantified using gravimetric analysis (analytical balance precision: 0.01 mg). Normality was assessed using the Shapiro–Wilk test and homogeneity of variance using Levene’s test. Normality assumptions were satisfied (Shapiro–Wilk test, all P > 0.05). Although Levene’s test indicated unequal variances ( P < 0.05), one-way ANOVA was considered appropriate because the study had equal group sizes ( n = 6 per group), for which one-way ANOVA is generally considered robust to moderate departures from the homogeneity of variance assumption. Duncan’s multiple range test was subsequently used for post hoc comparisons as the study was exploratory in nature and aimed to maximize sensitivity for detecting differences among adhesive groups. Significant differences were observed among adhesives (ANOVA, F = 748.465, P < 0.001). SBAs demonstrated minimal residue on skin (SAR: 0.21%; SAE: 22.54%), suggesting a predominantly adhesive failure pattern. In contrast, WBAs retained a substantial proportion of adhesive on the skin (DAR: 93.64%; PAA: 83.39%; DAH: 52.91%), consistent with an inferred cohesive or mixed-mode failure pattern. Adhesive residue may provide a clinically relevant indicator of the practical burden associated with adhesive removal and may help infer predominant failure patterns. Silicone-based adhesives demonstrated significantly lower adhesive residue on the skin than water-based adhesives in this pilot study. These findings provide preliminary evidence to support consideration of residue characteristics during adhesive selection and warrant confirmation in larger clinical studies. Clinical Trials Registry–India (CTRI/2026/06/112264), prospectively registered.