Bio-Active Denture Soft Liner Materials from Design to Application: In Vitro Approach

Abstract

Background: Denture soft liners are mainly used in order to decrease pain as well as improve compliance in patients who are not able to tolerate denture induced stresses. Soft liner materials are currently used as dynamic impression materials and also as adjuncts in prosthodontics for management of traumatized oral mucosa due to their accuracy and stability. The use of the soft liners as an addition to the acrylic denture and prolonged use has a significant problem which is accumulation and colonization of Candida albicans and other microorganisms which are a main cause of denture stomatitis. Aim Due to our interest in design and evaluation of bio-active materials such as copaiba oil, Propolis (Red, Brazilian) and Propolis (Chilean, Rotterdam Laboratory) as the bio-active materials has been shown to be promising as a topical antifungal agent, with recent clinical data indicating efficacy in the treatment of oral candidiasis [1]. The major advantages of natural medicinal plant extracts as antimicrobial agents include enhanced safety and stability without any side effects, which lack with both organic and inorganic antimicrobial agents. This in vitro study is undertaken with the aim to test the efficacy of the bio-active denture soft liner combined with Copaiba oil, Propolis (Red, Brasilian) and Propolis (Chilean, Rotterdam Laboratory) as well as combination of Chitosan/ Copaiba oil, Chitosan/Propolis (Red) and Chitosan/Propolis (Chilean, Rotterdam Laboratories) by investigating several biomechanical as well as effectiveness the against Candida albicans growth. Results: It has been reported that the bonding between resilient lining materials and denture base materials is affected by aging in water, the nature of the denture base material and the temperature. Resilient denture liners immersed in water leach out plasticizers and absorb water. These two mechanisms affect the denture compliance and dimensional stability. The results of the mechanical testing of resilient lining materials are important and help determining which materials have the better resistance under tensile or shear loading. The experiments are currently on the way in our laboratory to evaluate the tensile strength of the bio-active modified soft re-liner materials as well as asses the performance of the materials under thermocycling conditions. All the test samples gave an average inhibition zone larger than the tetracycline control disc, thereby confirming the antibacterial activity of the different bio-active containing combinations against Candida albicans. Using the Student's T-test (p<0.01), there was a significant difference between the rest of the samples when compared to each other and the positive control. The amount of bio-actives (such as Propolis (Brazilian, Red), Propolis (Chilean) and Copaiba oil) release in swelling media was analyzed after 1, 2, 24, and 96 h of immersion. The amount of bio-actives (such as Propolis (Brazilian, Red), Propolis (Chilean) and Copaiba oil) release in swelling media was analyzed after 1, 2, 24, and 96 h of immersion. The propolis release by polymeric systems usually occurs in two steps: the release of certain amounts of propolis in the first day of swelling as well as a prolonged release in some cases. A trend could be observed in all curves after 4 days of immersion: there was a high bioactive release in the initial hours and the cumulative release reached constant values up to 1 day of immersion. No prolonged release was observed. Nonetheless, the samples released more bioactive to PBS than to Solution pH 4.0, probably indicating that the propolis release can be influenced by the media pH. Conclusion: The major advantages of natural medicinal plant extracts as antimicrobial agents include enhanced safety and stability without any side effects, which lack with both organic and inorganic antimicrobial agents. This in vitro study is undertaken and evaluated the efficacy of the bio-active denture soft liner combined with Copaiba oil, Propolis (Red, Brazilian) and Propolis (Chilean, Rotterdam Laboratory) as well as combination of Chitosan/Copaiba oil, Chitosan/Propolis (Red, Brazilian) and Chitosan/Propolis (Chilean, Rotterdam Laboratories) and demonstrated that the designed materials are suitable for further development of bio-active soft reliner materials.