This study aimed to determine the characteristics of Hibiscus sabdariffa as a fiber-reinforcement material for denture acrylic resins. The Hibiscus sabdariffa fiber was extracted by hot water retting. The fiber was treated at room temperature in aqueous solution of NaOH for 8 hours at 8% concentration. Micrometre gauge and Field emission scanning electron microscope (FE-SEM), Archimedes principle, Fourier transform infrared (FTIR) spectroscopy, and Thermogravimetric analyser were used to characterize the diameter, morphology, density, water content and absorption, functional chemical component and thermal behaviour of Hibiscus sabdariffa fiber. In addition, the reinforcing characteristics of Hibiscus sabdariffa fiber was evaluated using denture acrylic resin. The flexural strength was measured in line with ASTM D 790 using Lloyd TM three point bending machine. In line with ASTM D 256, the impact strength was measured using Hounsfield TM charpy tester. The Micrometre gauge and FE-SEM analysis confirmed that diameter of Hibiscus sabdariffa fiber is within the range of other established reinforcing lignocellulosic fibers so also are the density, moisture content and absorption. The FTIR spectroscopy and TGA analysis confirmed the presence of cellulose, hemicellulose and other components in the fiber which were modified by treatment resulting in decreased hydrophilicity of the fibers thereby improving the thermal stability of the fiber. Furthermore, the bond fiber/matrix adhesion was improved which resulted in improve mechanical properties of the composite. The salient features of this study indicated that based on the suitable properties, Hibiscus sabdariffa fiber can be applied to reinforcing denture acrylics. In addition, and potentially, the use of Hibiscus sabdariffa fiber in reinforcement of denture acrylic resins can trigger further economic benefit while ensuring sustainable, green and safer environment.

Model for predicting the quantity of water evaporated during the primary

The poor mechanical properties of denture base acrylic resins can cause dentures to fracture either through impact or stress fatigue. Various metal reinforcing materials such as powders, nets, plates and wires together with synthetic fibres are therefore used to improve the strength properties of denture base acrylic resins. Despite their benefits, they are difficult to apply during fabrication, are costly, non-recyclable, and not environmentally friendly. The suitability of Hibiscus sabdariffa (H. sabdariffa) as a fibre reinforcement material for denture base acrylic resins was therefore investigated. A quantitative research paradigm and a two-phased experimental research design was used. The preliminary study used Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and field emission scanning electron microscope (FE-SEM) to assess the characteristics of, and the effect of, mercerisation on H. sabdariffa fibres. In determining the suitability of H. sabdariffa fibres, fibre diameter, fibre density, moisture content and absorption were examined. The main study investigated the mechanical and physical properties of two sample groups namely: the unreinforced (control) group and the H. sabdariffa fibre-reinforced (test) group denture base acrylic resins. The flexural strength, impact strength, specific wear rate, hardness and water absorption behaviour were determined in line with ASTM D 790 and D 256, G 99, D 2583 and D 570 methods of testing, respectively. Parametric and non-parametric tests were used to analyse the mean differences (p = 0.05) between the unreinforced and the H. sabdariffa fibre-reinforced denture base acrylic resins. The preliminary study revealed that H. sabdariffa fibres favourably compared to other lignocellulosic fibres in terms of fibre diameter, fibre density, water content and absorption behaviour. In the main study, a t-test revealed that there were significant differences in flexural strength at 0oC (p < 0.0001) and at 65oC (p < 0.0025) between the two sample groups. Similarly, there were significant differences in the impact strength between the two sample groups at 0oC (p < 0.031) and at 65oC (p < 0.0001). In contrast to the 200g load, there were significant differences (p < 0.044) in the specific wear rate of the unreinforced and the H. sabdariffa fibre-reinforced denture base acrylic resins at the 500g load. The hardness values revealed no significant differences (p > 0.707) between the two sample groups. There were however, significant differences (p < 0.041) in the water absorption rate between the two sample groups. Overall, the prominent features of this study showed that H. sabdariffa fibre is a suitable reinforcement fibre material for denture base acrylic resins and is in compliance with ISO 1567: 1999. Although this study found that H. sabdariffa fibres can be used as reinforcement material for denture base acrylic resins, the results cannot be generalised to clinical conditions, therefore in vitro and in vivo investigations are recommended.

Tapioca is a starch extracted from the root of the cassava plant (Manihot exculenta). Cooks and bakers rely on it for baking and for soup thickener but in dentistry the appropriate mixture in weight and volume of starch, water, glycerin and ethyl alcohol forms separating medium. A separating medium prevents direct contact between the denture based resin and the model surface. This study aimed at production of dental separating medium using tapioca extracted from Manihot exculenta in Enugu, Nigeria. The research was carried out between August and September, 2018 in Enugu, Nigeria. The study adopted a three phased experimental approach using the same procedures but different weight and volume compositions. Structured, pretested Product Evaluation Data Sheet was used to evaluate the product by selected Practicing Dental Technologists in Enugu State, Nigeria. The resultant separating medium from experiment III with the following composition: starch flour 1200g, glycerin 500ml, ethyl alcohol 500ml, colorant 500ml and 4000ml of distilled (hot and cold) water. There was significant agreement among the respondents in the flow ability of the product 8(40%); excellent product effectiveness 8 (40%); smoothness 8 (40%), and color stability of the product 10 (50%). These findings suggests that dental separating medium can be produced locally in Enugu, Nigeria. Therefore, more attention needs to be paid in the production process, which will facilitate easy practice of Dental Technology, and also conserve huge foreign exchange being spent in the importation of separating medium in Nigeria.

Dental inlay wax is a mixture of several waxes, usually containing paraffin wax, ceresin wax, beeswax and other natural and synthetic waxes. It is used to prepare patterns for gold or other metallic materials in the fabrication of inlays, crowns and bridges. Inlay wax is used for the same purpose as casting wax in the formation of pattern mostly for metallic casting in Dental technology. This study aimed at producing dental inlay wax using locally sourced materials in Enugu, Nigeria. The research was carried out between July to September, 2018 in Enugu, Nigeria. The study adopted a three phased experimental approach using the same procedures but different weight compositions. Structured, pretested Product Evaluation Data Sheet was used to evaluate the product by selected Practicing Dental Technologists in Enugu State, Nigeria. The resultant wax from experiment III with the following composition: 60g Paraffin wax, 5g Beeswax, 25g Carnauba wax, 10g Ceresin wax and (35g) of green ketchup colorant gave the best result. Its properties are comparable to the conventional Dental Inlay wax. There was significant agreement among the respondents in the smoothness of the product (40%); excellent dimensional stability and product effectiveness (40%); flow and burnout of the product (35%), and color stability of the product (45%). These findings suggests that dental inlay waxes can be produced locally in Enugu, Nigeria. Therefore, more attention needs to be paid in the production process, which will facilitate easy practice of Dental Technology, and also conserve huge foreign exchange being spent in the importation of inlay wax in Nigeria.