Analysis of the Hardness of Soft Relining Materials for Removable Dentures

Ewa Białożyt-Bujak,Magdalena Orczykowska,Aleksandra Czelakowska,Agata Białożyt,Małgorzata Skucha-Nowak,Jacek Kasperski,Magdalena Wyszyńska,Grzegorz Chladek,Andrzej Gala

doi:10.3390/ijerph18189491

Abstract

The main functional feature of elastomeric soft linings materials is the ability to discharge loads in the tissues of the mucosa. As a result, there are fewer injuries to the mucosa and chewing ability increases. In addition, these prostheses are more comfortable in the patient’s opinion. To obtain the equal distribution of forces on the muco-bone basis and to reduce the traumatizing effect of the denture plate for patients using full dentures, soft lining materials can be used. Aim of the study: the aim of the work was a comparative laboratory study of ten materials used for soft lining of acrylic complete dentures. Methodology: Materials based on acrylates (Vertex Soft, Villacryl Soft, Flexacryl Soft) and on silicones (Sofreliner Tough Medium, Sofreliner Tough Medium, Ufi Gel SC, GC Reline Soft, Elite Soft Relining, Molloplast) were compared. Laboratory tests include tests of changes in Shore’a A hardness of soft lining material. The tests were conducted taking into account 90 day term aging in the distilled water environment based on the methodology presented in the European Standard ISO 10139-2. Results: For most silicone materials, only small changes in hardness were found in the range of 0.7 (Ufi Gel SC) to 3.3 (Sofreliner Tough Medium) on the Shore A scale. The exception was GC Reline Soft, for which a marked increase in hardness was noted. All materials based on acrylates were characterized by successive increase in hardness over time. However, in the case of the Vertex Soft material, the increase in hardness was relatively small (5.5 ShA).

Highlights

The use of acrylic full and partial removable dentures as well as postoperative dentures can be extremely difficult for patients
The requirements of the standard in this respect were not met by the Flexacryl Soft material, for which the hardness values exceeded the acceptable criteria
In the case of Vertex Soft material, the increase in hardness was relatively small and amounted to 10.5%. These results clearly show that acrylic materials are much less stable in terms of hardness over time than silicone materials

Summary

Introduction

The use of acrylic full and partial removable dentures as well as postoperative dentures can be extremely difficult for patients. The most common problems reported by patients were those related to reduced functioning, such as difficulty in chewing, swallowing freely, and the occurrence of pain and discomfort [1–6]. Despite the correct construction of the prosthesis and its good fit, patients often report pain related to the transfer of occlusive forces to the prosthetic base. The long-term traumatizing effect of the prosthesis plate results mucosal injuries in the form of difficult to heal abrasions and bedsores [7–10]. In order to support prosthetic treatment and restore the physiological function of the stomatognathic system, soft relining materials can be used to cover the mucosal surface of the prosthesis [11]. The flexible lining layer affects the distribution of chewing forces

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Conclusion