The effect of aloe vera oil addition on the mechanical properties of soft denture liners: an in vitro study

Huda Jaafar Naser

doi:10.17126/joralres.2026.012

Huda Jaafar Naser Department of Orthodontics, University of Misan, College of Dentistry, Maysan, Iraq http://orcid.org/0000-0001-8719-9013

DOI: https://doi.org/10.17126/joralres.2026.012

Keywords: Aloe, Denture liners, Tensile strength, Hardness tests, Viscoelastic substances, Materials testing

Abstract

Background: Soft denture liners are used to improve comfort and stress distribution in edentulous patients, yet their mechanical durability remains a major limitation. Natural additives such as Aloe vera oil have gained interest for their potential to enhance biological compatibility and modify the viscoelastic performance of these materials. Objective: This study aimed to investigate how incorporating different concentrations of Aloe vera oil affects the mechanical properties of a silicone-based soft liner.
Material and Methods: Silicone soft liner specimens containing the three Aloe vera oil concentrations (0.25%, 0.75%, and 1.25% by weight) and a control group (0%) were prepared according to ISO 10139-2 standards. Each group consisted of ten samples (n = 10). All specimens were stored in distilled water at 37 ± 1 °C for 24 h before testing. Mechanical tests were performed using a universal testing machine and analyzed by one-way and two-way ANOVA (α = 0.05).
Results: The addition of Aloe vera oil produced a concentration-dependent modification of the liner’s properties. Tear resistance and tensile energy absorption significantly increased up to 0.75% (6.42 ± 0.24 N/mm and 135.7 ± 4.8 J/m², respectively; p< 0.001) before slightly decreasing at 1.25%. Shore A hardness decreased gradually with increasing oil content, maintaining desirable softness at 0.75% after 30 days (48.6 ± 1.2). Dynamic mechanical analysis revealed that the 0.75% group exhibited the lowest storage modulus (2.91 MPa) and the highest damping factor (tan δ = 0.40), reflecting improved elasticity and energy dissipation.
Conclusion: Incorporating 0.75% Aloe vera oil into a silicone-based soft liner optimally enhanced its flexibility, resilience, and damping capacity without compromising dimensional stability.

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