Applied Mechanics and Materials Vol. 910

Abstract: Restorative material is exposed to oral fluid and may have its color stability affected. Oral fluids may be influenced by beverages, such as red dragon fruit juice, which has low pH. The aim of this study is to investigate the effects of red dragon fruit juice on color stability of self-adhesive flowable composite (SAFC). In this study, 50 samples of SAFC discs (diameter = 6mm, height = 3mm) were divided into 5 groups (n=10); sample 1 was control immersed in distilled water for 24 hours, sample 2 was immersed for 8 hours in red dragon fruit juice and 16 hours in distilled water (37°C) for total 6 days (sample 2A) and for total 12 days (sample 2B), sample 3 was immersed in distilled water for 24 hours in distilled water (37°C) for total 6 days (sample 3A) and for total 12 days (sample 3B). Color stability was tested using VITA Easy-shade V. The value of color deviation (ÄE), value of lightness (ÄL), value of chrome (ÄC), and value of hue (Äh). Samples were then categorized to group A by substracting the scores between sample 1 and 2A; group B between sample 1 and 2B; group C between sample 1 and 3A; and group D between sample 1 and 3B. One way ANOVA test showed there was significant differences (p<0.05) of ÄE, ÄL, ÄC value, while Äh values showed no significant differences (p>0.05). The difference between group 1 and group 3B has the largest overall color changes with ÄE 1.01 ± 0.099. Discoloration of self-adhesive flowable composite can be influenced by water sorption, polymerization, composition, immersion time and the type of soaking solution which is red dragon fruit juice and distilled water. This study concluded that red dragon fruit juice as also distilled water affects color stability of SAFC.

Abstract: Chronic apical abscesses are triggered by bacteria belonging to the Staphylococcus and Streptococcus genus. The use of adequate endodontic treatments and materials is essential for long-term performance treatment. Camphorated parachlorophenol has high antibacterial activity, evaporating continuously and diffusing throughout the root canals. This study aims to determine the inhibitory effect of camphorated parachlorophenol on Staphylococcus and Streptococcus in a chronic apical abscess. This experimental study using the well-diffusion test and the Davis and Stout inhibitory zone classification. Six Staphylococcus and one Streptococcus isolated from the apical abscess root canal are used in this study. The 50% and 75% camphorated parachlorophenol with chlorhexidine gluconate 2% as a positive control and Dimethyl sulfoxide (DMSO) as a negative control were test the sensitivity of bacteria Staphylococcus cohnii, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus saprophyticus, Staphylococcus warneri and Streptococcus salivarius. The inhibitory zone diameter was calculated for each concentration and bacteria. Staphylococcus and Streptococcus genus were found to be 100 percent highly susceptible to camphorated parachlorophenol, while Staphylococcus genus were 50 percent and 75 percent extremely susceptible. The inhibitory zone of camphorated parachlorophenol 50 percent was slightly higher than the inhibitor zone of camphorated parachlorophenol 75 percent. The highest significant ratios of camphorated parachlorophenol 50 percent and 75 percent inhibitory zone were found in Staphylococcus hominis, Staphylococcus warneri, and Staphylocccus saprophyticus. Antibacterials in chemical compounds affect bacteria through three mechanisms: damaging cell membranes containing lipids, modifying proteins, or modifying DNA. In conclusion, camphorated parachlorophenol as a medicament has an inhibitory effect to Staphylococcus and Streptococcus genus. Staphylococcus epidermidis, Staphylococcus warneri, Staphlyococcus saprofiticus, Staphlococcus haemoliticus, Staphlyococcus cohnii, Staphlyococcus hominis, and Streptococcus salivarius were highly susceptible to camphorated parachlorophenol 50% and 75%.

Abstract: Fluoride varnish is commonly used as topical fluoride therapy to prevent dental caries. Dental caries is a dissolution of tooth surface caused by the metabolic activity of Streptococcus mutans in the presence of carbohydrates. Fluoride varnishes containing antibacterial agents significantly affect the inhibition zone of Streptococcus mutans. Prior studies also note the inhibitory effect of wuluh starfruit (Averrhoa bilimbi L.) leaves extracts and fast release fluoride varnish containing red betel (Piper crocatum) leaves extracts on Streptococcus mutans. The purpose of this study was to evaluate the antibacterial effect of adding wuluh starfruit leaves extracts, and red betel leaves extracts to a formulation of fluoride varnish on the growth inhibition of Streptococcus mutans, the fluoride ion release, and the pH obtained from the fluoride varnish. The concentration of antibacterial extracts used was 0.1 g/mL each and MI Varnish served as control. The growth inhibition zone of Streptococcus mutans was measured using disk-diffusion agar method with 3 repetitions. The data produced were analyzed using the Kruskal-Wallis and Mann-Whitney U-tests. Fluoride varnishes containing antibacterial agents used in this study resulted in greater inhibition zone of Streptococcus mutans than control (P < 0.05). The addition of red betel leaves extracts resulted in greater mean diameter of inhibition zone (14.22 mm) than that of wuluh starfruit leaves extracts (13.75 mm), but there was no significant difference (P > 0.05). The fluoride ion release of fluoride varnish containing red betel leaves extracts and wuluh starfruit leaves extracts after 360 minutes is 269.08 mg/L and 229.32 mg/L, respectively. The pH of both fluoride varnishes is above the critical pH of hydroxyapatite. Thus, wuluh starfruit leaves extracts, and red betel leaves extracts have the potential to be used as one of the ingredients in the formulation of fluoride varnish to achieve better growth inhibition of Streptococcus mutans.

Abstract: Most of the materials used in dentistry contain fillers as part of their composition to modify their chemical and mechanical properties. Filler size reduction needs economic and environmentally friendly materials to control the viscosity on a simple precipitation method using surfactant. Technical surfactants with more affordable prices also could develop filler size reduction. The study aims to analyse different technical surfactant effects on the glutinous rice flour precipitation method of filler size reduction used as an organic filler in dental applications. Precipitation technique is used by preparing the mixture by adding glutinous rice solution of bi-distilled water or sodium hydroxide with different 4% technical surfactant (Span 80 and Tween 80) dropwise to absolute ethanol. Samples were centrifuged at 3000 and 6000 rpm, then washed and characterized using Scanning Electron Microscope (SEM), Fourier Transform Infra-Red (FTIR), X-ray Diffraction (XRD), and Dynamic Light Scattering (DLS). As the result of this study, a size reduction of 714.8 nm with spherical and rod-like shapes could be generated from glutinous rice flour with the addition of Span 80 technical surfactant in 3000 rpm centrifugation speed for organic filler materials using sodium hydroxide solvent. This study suggested an opportunity for the country’s available source improvement in determining dental materials viscosity and its reinforcement.

Abstract: Artificial teeth are components in removable partial dentures or complete dentures. The denture will be exposed to various liquids from food and beverages in daily use. On the other hand, dentures should also be cleaned regularly with various cleaning methods, either mechanically or chemically. Exposure to various things can result in changes in the surface structure of artificial teeth. The purpose of this study was to evaluate the surface roughness of the denture elements that had been exposed to coffee and then cleaned mechanically and chemically. A total of 30 artificial teeth were immersed in the coffee solution for 2.5 days in an incubator at 37 ° C. Then, the samples were divided into three groups (n = 10) according to the cleaning treatment. Group A was cleaned mechanically using an electric toothbrush and toothpaste for 2 minutes, group B was cleaned chemically by soaking in a solution of alkaline peroxide for 3 minutes, and Group C was the control group and cleaned through immersion in distilled water for 3 minutes. All samples were measured for surface roughness before and after immersion in coffee solution and after cleaning treatment using a Profilometer (Surfcorder SE 1700). Data were analyzed using a paired-sample t-test and ANOVA. The surface roughness of artificial teeth (3.62 µm) increases to 4.092 µm after immersion in coffee solution (p<0.05). After the denture cleaning procedure was carried out, although group B show the highest values (3.32 µm), but the difference in the mean surface roughness between the cleaning treatment groups did not show a significant difference (p> 0.05). As the conclusion, the denture cleaning method in this study (mechanical and chemical) did not give negative results on the surface roughness of the artificial teeth that had been exposed to the coffee solution.

Abstract: One of the problems in orthodontic treatment is friction. Some of the factors that support friction are archwire material, archwire dimensions, bracket material, surface roughness, type of ligation, environmental humidity, and bracket position, angulation angle between bracket and wire, changes in the surface of the archwire and bracket. The aim of this study is to analyse the difference in friction between the two branded bracket designs and a new patented bracket (patent no. IDP000069597). The production method for this new bracket is different, however, uses the same material of 17-4 PH stainless steel. There are three groups in this research, one sample of bracket each from two different branded and one sample of a new bracket design. All three groups were tested for microstructure, then tested for measurement of friction between bracket slots and archwire. The microstructure of the two branded brackets has a martensitic phase that is not as dense as the new bracket, which is due to the different manufacturing method processes. The two branded brackets use the metal injection molding method, while the new brackets use the investment casting method. The friction test results show that there are significant differences between the three groups of brackets. One of the branded brackets (A) has the lowest friction, but branded bracket (B) does not have different friction with the new bracket. Differences in design and manufacturing methods of orthodontic bracket affect the friction between orthodontic brackets and archwires even though they use the same material.