The Effect of Incorporation Kappa-Carrageenan Powder on the Physical and Mechanical Properties of the Heat-Cured Acrylic-based Soft Denture Lining Material in Clinical Use

Abstract

Background: Soft denture relining materials have been introduced to prosthetic dentistry since long time
to improve the patient’s acceptance to dental prosthesis. However, with the growing need to provide the
patients with dentures that have improved comfort and masticatory efficiency, there is a growing demand to
improve several features of the denture lining materials. Therefore, the aims of this study was to evaluate
the effect of incorporation kappa-carrageenan powder as antifungal agent on the hardness and peel bond
strength of the heat-cured acrylic-based soft denture lining material.
Materials and Methods: Two percentages of kappa-carrageenan powder (1.5wt.% and 2wt.%) have been
selected based on the pilot study that produced the best antifungal effect. A total of sixty samples were
prepared and divided into three equal groups groupA:0.0wt.%, groupB:1.5wt.%, groupC:2wt.% of kappacarrageenan powder additive. Each group was further subdivided into two equal groups for shore-A hardness
test and peel bond strength test. Fourier transform infrared spectroscopy (FTIR) analysis was performed to
investigate if there is any chemical reaction between the soft lining material and the kappa-carrageenan
powder, scanning electron microscope (SEM) was used to determine the distribution of kappa-carrageenan
powder in the soft liner matrix.
Results: All the resulted data were analysed using “one-way analysis of variance (ANOVA) and Dunnet
T3 post-hoc test at a significance level of p<0.05”. The result of shore-A hardness test revealed significant
increase (P<0.05) in the values of hardness of both experimental groups (B and C) when compared with the
control group(A). Peel bond strength test revealed non-significant decrease (P>0.05) in the values of peel
bond strength for experimental group(B), while there was significant decrease (P<0.05) for the experimental
group(C) when compared to the control group. FTIR analysis showed no difference in the spectra between
control group and experimental group this means that there is no chemical interaction between the two
materials. SEM test results showed a degree of agglomeration of the kappa-carrageenan powder into the soft
liner matrix.
Conclusion: Adding kappa-carrageenan powder to the soft liner affected the physical and mechanical
properties of the lining material and the most adverse effect was noted for the group C(2 wt.%) but all effects
was in the acceptable range for clinical use.